Viability preserved capture of microorganism by plasma functionalized carbon-encapsulated iron nanoparticles

NASA Astrophysics Data System (ADS)

Viswan, Anchu; Sugiura, Kuniaki; Nagatsu, Masaaki

2015-09-01

Carbon-encapsulated iron nanoparticles (Fe@C NPs) were synthesized by DC arc discharge method. Carbon encapsulation makes the particles hydrophobic, however for most of the biomedical applications they need to be hydrophilic. To attain this, the particles were amino functionalized by RF plasma. Effect of gas mixture ratio (Ar/NH3), pretreatment, post-treatment times and RF power were optimized. By varying the RF plasma conditions, the amino group population on the surface of Fe@C NPs were increased. With conventional chemical method the amino group population on particles, synthesized in different conditions was found to be ranging from 3-7 × 104 per particle. Bioconjugation efficiency of the nanoparticles was examined by biotin-avidin system, which can be simulated for antigen-antibody reactions. Results from the UV absorption and fluorescence spectroscopy shows increment in bioconjugation efficiency, with the increase of amino group population on the nanoparticles. After confirming the bioconjugation efficiency, the amino functionalized Fe@C NPs were modified with antibodies for targeting specific microorganisms. Our aim is to capture the microbes in viable and concentrated form even from less populated samples, with lesser time compared to the presently available methods. This work has been supported in part by Grant-in-Aid for Scientific Research (Nos. 21110010 and 25246029) from the Japan Society for the Promotion of Science (JSPS).

Controlling chitosan-based encapsulation for protein and vaccine delivery

PubMed Central

Koppolu, Bhanu prasanth; Smith, Sean G.; Ravindranathan, Sruthi; Jayanthi, Srinivas; Kumar, Thallapuranam K.S.; Zaharoff, David A.

2014-01-01

Chitosan-based nano/microencapsulation is under increasing investigation for the delivery of drugs, biologics and vaccines. Despite widespread interest, the literature lacks a defined methodology to control chitosan particle size and drug/protein release kinetics. In this study, the effects of precipitation-coacervation formulation parameters on chitosan particle size, protein encapsulation efficiency and protein release were investigated. Chitosan particle sizes, which ranged from 300 nm to 3 μm, were influenced by chitosan concentration, chitosan molecular weight and addition rate of precipitant salt. The composition of precipitant salt played a significant role in particle formation with upper Hofmeister series salts containing strongly hydrated anions yielding particles with a low polydispersity index (PDI) while weaker anions resulted in aggregated particles with high PDIs. Sonication power had minimal effect on mean particle size, however, it significantly reduced polydispersity. Protein loading efficiencies in chitosan nano/microparticles, which ranged from 14.3% to 99.2%, was inversely related to the hydration strength of precipitant salts, protein molecular weight and directly related to the concentration and molecular weight of chitosan. Protein release rates increased with particle size and were generally inversely related to protein molecular weight. This study demonstrates that chitosan nano/microparticles with high protein loading efficiencies can be engineered with well-defined sizes and controllable release kinetics through manipulation of specific formulation parameters. PMID:24560459

Development of native and modified banana starch nanoparticles as vehicles for curcumin.

PubMed

Acevedo-Guevara, Leonardo; Nieto-Suaza, Leonardo; Sanchez, Leidy T; Pinzon, Magda I; Villa, Cristian C

2018-05-01

In recent years, starch nanoparticles have been of great interest for drug delivery due to their relatively easy synthesis, biocompatibility, and vast amount of botanical sources. Native and acetylated starch obtained from green bananas were used for synthesis of curcumin-loaded starch nanoparticles. Mean particle size, encapsulation efficiency, and curcumin release in simulated gastric and intestinal fluids were studied. Both nanosystems showed sizes lower than 250 nm and encapsulation efficiency above 80%, with acetylated banana starch nanoparticles having the capacity to encapsulate more curcumin molecules. Both FTIR and XRD analyses showed that starch acetylation allows stronger hydrogen bond interaction between curcumin and the starch matrix, thus, higher encapsulation efficiency. Finally, curcumin release studies showed that acetylated banana starch nanoparticles allowed more controlled release, probably due to their stronger hydrogen bond interaction with curcumin. Copyright © 2018. Published by Elsevier B.V.

Process optimization by use of design of experiments: Application for liposomalization of FK506.

PubMed

Toyota, Hiroyasu; Asai, Tomohiro; Oku, Naoto

2017-05-01

Design of experiments (DoE) can accelerate the optimization of drug formulations, especially complexed formulas such as those of drugs, using delivery systems. Administration of FK506 encapsulated in liposomes (FK506 liposomes) is an effective approach to treat acute stroke in animal studies. To provide FK506 liposomes as a brain protective agent, it is necessary to manufacture these liposomes with good reproducibility. The objective of this study was to confirm the usefulness of DoE for the process-optimization study of FK506 liposomes. The Box-Behnken design was used to evaluate the effect of the process parameters on the properties of FK506 liposomes. The results of multiple regression analysis showed that there was interaction between the hydration temperature and the freeze-thaw cycle on both the particle size and encapsulation efficiency. An increase in the PBS hydration volume resulted in an increase in encapsulation efficiency. Process parameters had no effect on the ζ-potential. The multiple regression equation showed good predictability of the particle size and the encapsulation efficiency. These results indicated that manufacturing conditions must be taken into consideration to prepare liposomes with desirable properties. DoE would thus be promising approach to optimize the conditions for the manufacturing of liposomes. Copyright © 2017 Elsevier B.V. All rights reserved.

[Preparation of ibuprofen/EC-PVP sustained-release composite particles by supercritical CO2 anti-solvent technology].

PubMed

Cai, Jin-Yuan; Huang, De-Chun; Wang, Zhi-Xiang; Dang, Bei-Lei; Wang, Qiu-Ling; Su, Xin-Guang

2012-06-01

Ibuprofen/ethyl-cellulose (EC)-polyvinylpyrrolidone (PVP) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading as the main evaluation index, orthogonal experimental design was used to optimize the preparation process of EC-PVP/ibuprofen composite particles. The experiments such as encapsulation efficiency, particle size distribution, electron microscope analysis, infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 40 degrees C, crystallization pressure 12 MPa, PVP concentration 4 mgmL(-1), and CO2 velocity 3.5 Lmin(-1). Under the optimal conditions, the drug loading and encapsulation efficiency of ibuprofen/EC-PVP composite particles were 12.14% and 52.21%, and the average particle size of the particles was 27.621 microm. IR and DSC analysis showed that PVP might complex with EC. The experiments of in vitro dissolution showed that ibuprofen/EC-PVP composite particles had good sustained-release effect. Experiment results showed that, ibuprofen/EC-PVP sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Hybrid Encapsulated Ionic Liquids for Post-Combustion Carbon Dioxide (CO 2) Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennecke, Joan; Degnan, Thomas; McCready, Mark

Ionic liquids (ILs) and Phase Change Ionic Liquids (PCILs) are excellent materials for selective removal of carbon dioxide from dilute post-combustion streams. However, they are typically characterized as having high viscosities, which impairs their effectiveness due to mass transfer limitations, caused by the high viscosities. In this project, we are examining the benefits of encapsulating ILs and PCILs in thin polymeric shells to produce particles of approximately 100 to 600 μm in diameter that can be used in a fluidized bed absorber. The particles are produced by microencapsulation of the ILs and PCILs in CO 2-permeable polymer shells. Here wemore » report on the synthesis of the IL and PCIL materials, measurements of thermophysical properties including CO 2 capacity and reprotonation equilibrium and kinetics, encapsulation of the ILs and PCILs, mechanical and thermodynamic testing of the encapsulated materials, development of a rate based model of the absorber, and the design of a laboratory scale unit to test the encapsulated particles for CO 2 capture ability and efficiency. We show that the IL/PCIL materials can be successfully encapsulated, that they retain CO 2 uptake capacity, and that the uptake rates are increased relative to a stagnant sample of IL liquid or PCIL powder.« less

Silica particles encapsulated poly(styrene-divinylbenzene) monolithic stationary phases for micro-high performance liquid chromatography.

PubMed

Bakry, R; Stöggl, W M; Hochleitner, E O; Stecher, G; Huck, C W; Bonn, G K

2006-11-03

In the paper we demonstrate a new approach for the preparation and application of continuous silica bed columns that involve encapsulation (entrapment) of functionalized silica microparticles, which can be used as packing material in micro high performance liquid chromatography (micro-HPLC) and capillary electrochromatography (CEC). Like traditional packed columns, these capillaries possess characterized silica particles that offer high phase ratio and narrow pore size distribution leading to high retention and separation efficiency, respectively. More importantly, immobilization of the microparticles stabilizes the separation bed and eliminates the need for retaining frits. The developed capillary columns were fabricated in exactly the same way as a packed capillary column (slurry packing) but with an additional entrapment step. This immobilization of the packed bed was achieved by in situ polymerization of styrene and divinylbenzene in presence of decanol as a porogen and azobisisobutyronitrile as thermal initiator. Silica particles with different particle sizes and pore sizes ranging from 60 to 4000 A were studied. In addition different modified silica was used, including C-18 reversed phase, anion exchange and chiral stationary phases. Efficient separation of polyphenolic compounds, peptides, proteins and even DNA mutation were achieved using the developed technique depending on the properties of the silica particles used (particles pore size). For example, using 3 microm ProntoSIL C-18 particles with 300 A pore size, separation efficiencies in the range of 120,000-200,000 plates/m were obtained for protein separation, in a 6 cm x 200 microm i.d. capillary column. Using encapsulated silica C-18 with 1000 A pore size, separation of DNA homo and hetero duplexes were achieved under denaturing HPLC conditions for mutation detection. In addition, nucleotides were separated using anion exchange material encapsulated with poly(styrene-divinylbenzene) (PS/DVB), which indicated that the chromatographic properties of the silica packing material were still active after polymerization. The prepared capillary columns were found to be stable and could easily be operated continuously up to a pressure of 350 bar without column damage and capillary can be cut to any desired length.

Determination of silica coating efficiency on metal particles using multiple digestion methods.

PubMed

Wang, Jun; Topham, Nathan; Wu, Chang-Yu

2011-10-15

Nano-sized metal particles, including both elemental and oxidized metals, have received significant interest due to their biotoxicity and presence in a wide range of industrial systems. A novel silica technology has been recently explored to minimize the biotoxicity of metal particles by encapsulating them with an amorphous silica shell. In this study, a method to determine silica coating efficiency on metal particles was developed. Metal particles with silica coating were generated using gas metal arc welding (GMAW) process with a silica precursor tetramethylsilane (TMS) added to the shielding gas. Microwave digestion and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) were employed to solubilize the metal content in the particles and analyze the concentration, respectively. Three acid mixtures were tested to acquire the appropriate digestion method targeting at metals and silica coating. Metal recovery efficiencies of different digestion methods were compared through analysis of spiked samples. HNO(3)/HF mixture was found to be a more aggressive digestion method for metal particles with silica coating. Aqua regia was able to effectively dissolve metal particles not trapped in the silica shell. Silica coating efficiencies were thus calculated based on the measured concentrations following digestion by HNO(3)/HF mixture and aqua regia. The results showed 14-39% of welding fume particles were encapsulated in silica coating under various conditions. This newly developed method could also be used to examine the silica coverage on particles of silica shell/metal core structure in other nanotechnology areas. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparison of non-toxic methods for creating beta-carotene encapsulated in PMMA nanoparticles

NASA Astrophysics Data System (ADS)

Dobrzanski, Christopher D.

Nano/microcapsules are becoming more prevalent in various industries such as drug delivery, cosmetics, etc. Current methods of particle formation often use toxic or carcinogenic/mutagenic/reprotoxic (CMR) chemicals. This study intends to improve upon existing methods of particle formation and compare their effectiveness in terms of entrapment efficiency, mean particle size, and yield utilizing only non-toxic chemicals. In this study, the solvent evaporation (SE), spontaneous emulsification, and spontaneous emulsion solvent diffusion (SESD) methods were compared in systems containing green solvents ethyl acetate, dimethyl carbonate or acetone. PMMA particles containing encapsulated beta carotene, an ultraviolet sensitive substance, were synthesized. It was desired to produce particles with minimum mean size and maximum yield and entrapment of beta carotene. The mass of the water phase, the mass of the polymer and the pumping or blending rate were varied for each synthesis method. The smallest particle sizes for SE and SESD both were obtained from the middle water phase sizes, 200 g and 100 g respectively. The particles obtained from the larger water phase in SESD were much bigger, about 5 microns in diameter, even larger than the ones obtained from SE. When varying the mass of PMMA used in each synthesis method, as expected, more PMMA led to larger particles. Increasing the blending rate in SE from 6,500 to 13,500 rpm had a minimal effect on average particle size, but the higher shear resulted in highly polydisperse particles (PDI = 0.87). By decreasing the pump rate in SESD, particles became smaller and had lower entrapment efficiency. The entrapment efficiencies of the particles were generally higher for the larger particles within a mode. Therefore, we found that minimizing the particle size while maximizing entrapment were somewhat contradictory goals. The solvent evaporation method was very consistent in terms of the values of mean particle size, yield, and entrapment efficiency. Comparing the synthesis methods, the smallest particles with the highest yield and entrapment efficiency were generated by the spontaneous emulsification method.

Ramizol® encapsulation into extended release PLGA micro- and nanoparticle systems for subcutaneous and intramuscular administration: in vitro and in vivo evaluation.

PubMed

Wright, Leah; Rao, Shasha; Thomas, Nicky; Boulos, Ramiz A; Prestidge, Clive A

2018-04-11

Novel antibiotic Ramizol ® is advancing to clinical trials for the treatment of gastrointestinal Clostridium difficile associated disease. Despite this, previous studies have shown a rapid plasma clearance upon intravenous administration and low oral bioavailability indicating pure drug is unsuitable for systemic infection treatment following oral dosing. The current study aims to investigate the development of poly-lactic-(co-glycolic) acid (PLGA) particles to overcome this limitation and increase the systemic half-life following subcutaneous and intramuscular dosing. The development of new antibiotic treatments will help in combatting the rising incidence of antimicrobial resistance. Ramizol ® was encapsulated into PLGA nano and microparticles using nanoprecipitation and emulsification solvent evaporation techniques. Formulations were analyzed for particle size, loading level and encapsulation efficiency as well as in vitro drug release profiles. Final formulation was advanced to in vivo pharmacokinetic studies in Sprague-Dawley rats. Formulation technique showed major influence on particle size and loading levels with optimal loading of 9.4% and encapsulation efficiency of 92.06%, observed using emulsification solvent evaporation. Differences in formulation technique were also linked with subsequent differences in release profiles. Pharmacokinetic studies in Sprague-Dawley rats confirmed extended absorption and enhanced bioavailability following subcutaneous and intramuscular dosing with up to an 8-fold increase in T max and T 1/2 when compared to the oral and IV routes. Subcutaneous and intramuscular dosing of PLGA particles successfully increased systemic half-life and bioavailability of Ramizol ® . This formulation will allow further development of Ramizol ® for systemic infection eradication.

Gelled oil particles: a new approach to encapsulate a hydrophobic metallophthalocyanine.

PubMed

Siqueira-Moura, Marigilson P; Franceschi-Messant, Sophie; Blanzat, Muriel; Ré, Maria Inês; Perez, Emile; Rico-Lattes, Isabelle; Lattes, Armand; Tedesco, Antonio C

2013-07-01

Chloroaluminum phthalocyanine (ClAlPc) is a promising sensitizer molecule for photodynamic therapy, but its hydrophobicity makes it difficult to formulate. In this study, we have efficiently encapsulated ClAlPc into gelled soybean oil particles dispersed in water. 12-Hydroxystearic acid (HSA) and polyethyleneimine (PEI) were the gelling and stabilizing agents, respectively. The preparation process involved hot emulsification above the gelation temperature (Tgel), followed by cooling to room temperature, which gave a colloidal dispersion of gelled particles of oil in aqueous medium. The gelled particles containing ClAlPc had a medium diameter of 280 nm, homogeneous size distribution (polydispersity index ≈0.3) and large positive zeta potential (about +50 mV) and showed a spherical morphology. The gelled oil particle formulations exhibited good physical stability over a 6-month period. ClAlPc interfered with the HSA self-assembly only slightly, and decreased the gelation temperature to a small extent; however it did not affect gelation process of the oil droplets. The amounts of PEI and HSA employed during the preparation allowed us to control particle size and the dispersion stability, a phenomenon that results from complex electrostatic interactions between the positively charged PEI and the negatively charged HSA fibers present on the gelled particles surface. In summary, by using the right ClAlPc, HSA, and PEI proportions, we prepared very stable dispersions of gelled soybean oil particles with excellent ClAlPc encapsulation efficiency. The obtained colloidal formulation of gelled oil particles loaded with ClAlPc shall be very useful for photodynamic therapy protocols. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Characterisation of the Poly-(Vinylpyrrolidone)-Poly-(Vinylacetate-Co-Crotonic Acid) (PVP:PVAc-CA) Interpolymer Complex Matrix Microparticles Encapsulating a Bifidobacterium lactis Bb12 Probiotic Strain.

PubMed

Mamvura, C I; Moolman, F S; Kalombo, L; Hall, A N; Thantsha, M S

2011-06-01

The method of producing poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid) (PVP:PVAc-CA) interpolymer complex matrix microparticles in supercritical carbon dioxide (scCO2), encapsulating bacteria, has recently been developed. This study was aimed at probing the external and internal structure of these microparticles, which can be used in food. The encapsulation efficiency and distribution of encapsulated Bifidobacterium lactis Bb12 within these microparticles were also investigated. Scanning electron microscopy (SEM) revealed irregular, mostly small, smooth microparticles with no visible bacterial cells on the surface. However, some of the microparticles appeared to have porous surfaces. The results of a Microtrac S3500 particle size analyzer showed that the PVP:PVAc-CA interpolymer complex matrix microparticles encapsulating B. lactis Bb12 had an average particle size of 166.1 μm (<350 μm designated standard size for microparticles). The D 10, D 50 and D 90 values for these microparticles were 48.16, 166.06 and 382.55 μm, respectively. Both SEM and confocal laser scanning microscopy showed a high density of bacterial cells within the microparticles. An average encapsulation efficiency of 96% was achieved. Consequently, the microparticles have the potential to be evenly distributed in foods, deliver adequate amounts of probiotics and produce minimal adverse effects on the texture and mouth feel of the foods into which they are incorporated.

Cyclodextrin-insulin complex encapsulated polymethacrylic acid based nanoparticles for oral insulin delivery.

PubMed

Sajeesh, S; Sharma, Chandra P

2006-11-15

Present investigation was aimed at developing an oral insulin delivery system based on hydroxypropyl beta cyclodextrin-insulin (HPbetaCD-I) complex encapsulated polymethacrylic acid-chitosan-polyether (polyethylene glycol-polypropylene glycol copolymer) (PMCP) nanoparticles. Nanoparticles were prepared by the free radical polymerization of methacrylic acid in presence of chitosan and polyether in a solvent/surfactant free medium. Dynamic light scattering (DLS) experiment was conducted with particles dispersed in phosphate buffer (pH 7.4) and size distribution curve was observed in the range of 500-800 nm. HPbetaCD was used to prepare non-covalent inclusion complex with insulin and complex was analyzed by Fourier transform infrared (FTIR) and fluorescence spectroscopic studies. HPbetaCD complexed insulin was encapsulated into PMCP nanoparticles by diffusion filling method and their in vitro release profile was evaluated at acidic/alkaline pH. PMCP nanoparticles displayed good insulin encapsulation efficiency and release profile was largely dependent on the pH of the medium. Enzyme linked immunosorbent assay (ELISA) study demonstrated that insulin encapsulated inside the particles was biologically active. Trypsin inhibitory effect of PMCP nanoparticles was evaluated using N-alpha-benzoyl-L-arginine ethyl ester (BAEE) and casein as substrates. Mucoadhesive studies of PMCP nanoparticles were conducted using freshly excised rat intestinal mucosa and the particles were found fairly adhesive. From the preliminary studies, cyclodextrin complexed insulin encapsulated mucoadhesive nanoparticles appear to be a good candidate for oral insulin delivery.

Hybrid Encapsulated Ionic Liquids for Post-Combustion Carbon Dioxide (CO 2) Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennecke, Joan F; Degnan, Jr, Thomas Francis; McCready, Mark J.

Ionic liquids (ILs) and Phase Change Ionic Liquids (PCILs) are excellent materials for selective removal of carbon dioxide from dilute post-combustion streams. However, they are typically characterized as having high viscosities, which impairs their effectiveness due to mass transfer limitations, caused by the high viscosities. In this project, we are examining the benefits of encapsulating ILs and PCILs in thin polymeric shells to produce particles of approximately 100 to 600 µm in diameter that can be used in a fluidized bed absorber. The particles are produced by microencapsulation of the ILs and PCILs in CO 2-permeable polymer shells. Here wemore » report on the encapsulation of the IL and PCIL materials, thermodynamic testing of the encapsulated materials, mass transfer measurements in both a fluidized bed and a packed bed, determination of the effect of impurities (SO 2, NO x and water) on the free and encapsulated IL and PCIL, recyclability of the CO 2 uptake, selection and synthesis of kg quantities of the IL and PCIL, identification of scale-up methods for encapsulation and production of a kg quantity of the PCIL, construction and shakedown of the laboratory scale unit to test the encapsulated particles for CO 2 capture ability and efficiency, use of our mass transfer model to predict mass transfer and identify optimal properties of the encapsulated particles, and initial testing of the encapsulated particles in the laboratory scale unit. We also show our attempts at developing shell materials that are resistant to water permeation. Overall, we have shown that the selected IL and PCIL can be successfully encapsulated in polymer shells and the methods scaled up to production levels. The IL/PCIL and encapsulated IL/PCIL react irreversibly with SO 2 and NO x so the CO 2 capture unit would need to be placed after the flue gas desulfurization and NO x reduction units. However, the reaction with CO 2 in the presence of water is completely reversible. Therefore, it is not necessary to exclude water from the capsules. Mass transfer in the fluidized and packed beds confirm that the fluidized bed arrangement is preferred and that the mass transfer can be predicted accurately by the rate based model that we have developed. Absorption and desorption experiments in the laboratory scale unit show good uptake and recyclability.« less

Encapsulation of ethylhexyl methoxycinnamate, a light-sensitive UV filter, in lipid nanoparticles.

PubMed

Durand, L; Habran, N; Henschel, V; Amighi, K

2010-01-01

The aim of this study was to encapsulate ethylhexyl methoxycinnamate (EMC), a commonly used UVB filter, in a solid lipid matrix in order to obtain microparticles and then nanoparticles to reduce its photo-instability under UV light exposure. Glyceryl behenate, rice bran wax and ozokerite were investigated for encapsulating EMC. The suspensions of nanoparticles contained 70% encapsulated EMC (relative to the lipid mass). The absorbance level at 310 nm of suspensions containing nanoparticles was more than twice that of those containing microparticles. So, decreasing the size of particles improved the efficiency of light protection, regardless of the lipid material used. Moreover, free EMC presented a 30% loss of its efficiency after 2 h of irradiation, whereas the three NLC formulations showed a loss of absorbency between 10% and 21%. The in vitro cutaneous penetration test did not show a higher potential penetration for EMC contained in nanosuspensions compared to free EMC.

Electrostatic Self-Assembled Chitosan-Pectin Nano- and Microparticles for Insulin Delivery.

PubMed

Maciel, Vinicius B V; Yoshida, Cristiana M P; Pereira, Susana M S S; Goycoolea, Francisco M; Franco, Telma T

2017-10-12

A polyelectrolyte complex system of chitosan-pectin nano- and microparticles was developed to encapsulate the hormone insulin. The aim of this work was to obtain small particles for oral insulin delivery without chemical crosslinkers based on natural and biodegradable polysaccharides. The nano- and microparticles were developed using chitosans (with different degrees of acetylation: 15.0% and 28.8%) and pectin solutions at various charge ratios (n⁺/n - given by the chitosan/pectin mass ratio) and total charge. Nano- and microparticles were characterized regarding particle size, zeta potential, production yield, encapsulation efficiency, stability in different media, transmission electron microscopy and cytotoxicity assays using Caco-2 cells. The insulin release was evaluated in vitro in simulated gastric and intestinal media. Small-sized particles (~240-~1900 nm) with a maximum production yield of ~34.0% were obtained. The highest encapsulation efficiency (~62.0%) of the system was observed at a charge ratio (n⁺/n - ) 5.00. The system was stable in various media, particularly in simulated gastric fluid (pH 1.2). Transmission electron microscopy (TEM) analysis showed spherical shape particles when insulin was added to the system. In simulated intestinal fluid (pH 6.8), controlled insulin release occurred over 2 h. In vitro tests indicated that the proposed system presents potential as a drug delivery for oral administration of bioactive peptides.

Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

NASA Astrophysics Data System (ADS)

Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

2013-03-01

Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide- co-glycolide) (PLGA) microparticles (size 1-4 μm, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

Preparation of uniform-sized PELA microspheres with high encapsulation efficiency of antigen by premix membrane emulsification.

PubMed

Wei, Qiang; Wei, Wei; Tian, Rui; Wang, Lian-Yan; Su, Zhi-Guo; Ma, Guang-Hui

2008-07-15

Relatively uniform-sized poly(lactide-co-ethylene glycol) (PELA) microspheres with high encapsulation efficiency were prepared rapidly by a novel method combining emulsion-solvent extraction and premix membrane emulsification. Briefly, preparation of coarse double emulsions was followed by additional premix membrane emulsification, and antigen-loaded microspheres were obtained by further solidification. Under the optimum condition, the particle size was about 1 mum and the coefficient of variation (CV) value was 18.9%. Confocal laser scanning microscope and flow cytometer analysis showed that the inner droplets were small and evenly dispersed and the antigen was loaded uniformly in each microsphere when sonication technique was occupied to prepare primary emulsion. Distribution pattern of PEG segment played important role on the properties of microspheres. Compared with triblock copolymer PLA-PEG-PLA, the diblock copolymer PLA-mPEG yielded a more stable interfacial layer at the interface of oil and water phase, and thus was more suitable to stabilize primary emulsion and protect coalescence of inner droplets and external water phase, resulting in high encapsulation efficiency (90.4%). On the other hand, solidification rate determined the time for coalescence during microspheres fabrication, and thus affected encapsulation efficiency. Taken together, improving the polymer properties and solidification rate are considered as two effective strategies to yield high encapsulation.

Characteristics of eugenol loaded chitosan-tripolyphosphate particles as affected by initial content of eugenol and their in-vitro release characteristic

NASA Astrophysics Data System (ADS)

Cahyono, B.; A’yun, Qurrotu; Suzery, M.; Hadiyanto

2018-04-01

The aim of this research was to determine encapsulation efficiency, loading capacity and controlled release of eugenol loaded chitosan-tpp products which prepared by coaservation method. The characteristic of eugenol-loaded chitosan showed that %EE and % LC increased by increasing the initial eugenol content. The optimum of %EE (72.63%) and %LC (43.96%) were obtained at the ratio of chitosan to eugenol of 1:1.5. The FTIR spectrum showed the characteristic peaks of eugenol appearing on spectrum of eugenol encapsulated and blue-shift in the hydroxyl band from 3425.58 cm-1 in chitosan-tpp to 3417.86 cm-1 and 3394.72 cm-1 in eugenol loaded chitosan-tpp indicating that eugenol was successfully encapsulated. The surface morphologies of freeze-dried particles with the optimum %EE showed that more surface roughness and porosity than plain particles. Furthermore, the in vitro release of particles with minimum and optimum %EE were also investigated in acid (Simulated Gastric Fluid) and base (Simulated Intestinal Fluid) medium at ambient temperature.

Peptide/protein vaccine delivery system based on PLGA particles.

PubMed

Allahyari, Mojgan; Mohit, Elham

2016-03-03

Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted.

Peptide/protein vaccine delivery system based on PLGA particles

PubMed Central

Allahyari, Mojgan; Mohit, Elham

2016-01-01

abstract Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted. PMID:26513024

A novel alginate-encapsulated system to study biological response to critical-sized wear particles of UHMWPE loaded with alendronate sodium.

PubMed

Liu, Yumei; Shi, Feng; Bo, Lin; Zhi, Wei; Weng, Jie; Qu, Shuxin

2017-10-01

The aim of this study was to develop a novel alginate-encapsulated system (Alg beads) to investigate the cell response to critical-sized wear particles of ultra-high molecular weight polyethylene loaded with alendronate sodium (UHMWPE-ALN), one of the most effective drugs to treat bone resorption in clinic. The extrusion method was used to prepare Alg beads encapsulating rat calvarial osteoblasts (RCOs) and critical-sized UHMWPE-ALN wear particles with spherical morphology and uniform size. The morphology, permeability and stability of Alg beads were characterized. The proliferation, ALP activity, cell apoptosis and distribution of live/dead RCOs co-cultured with wear particles in Alg beads were evaluated. RCOs and critical-sized UHMWPE-ALN wear particles distributed evenly and contacted efficiently in Alg beads. Alg beads were both permeable to trypsin and BSA, while the smaller the molecular was, the larger the diffuse was. The proliferation of RCOs in Alg beads increased with time, which indicated that Alg beads provided suitable conditions for cell culture. The long-term stability of Alg beads indicated the possibility for the longer time of co-cultured cells with wear particles. Critical-sized UHMWPE-ALN and UHMWPE wear particles both inhibited the proliferation and differentiation of RCOs, and induced the apoptosis of RCOs encapsulated in Alg beads. However, these effects could be significantly alleviated by the ALN released from the critical-sized UHMWPE-ALN wear particles. The present results suggested that this novel-developed co-culture system was feasible to evaluate the cell response to critical-sized UHMWPE-ALN wear particles for a longer time. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization and evaluation of 5-fluorouracil-loaded solid lipid nanoparticles prepared via a temperature-modulated solidification technique.

PubMed

Patel, Meghavi N; Lakkadwala, Sushant; Majrad, Mohamed S; Injeti, Elisha R; Gollmer, Steven M; Shah, Zahoor A; Boddu, Sai Hanuman Sagar; Nesamony, Jerry

2014-12-01

The aim of this research was to advance solid lipid nanoparticle (SLN) preparation methodology by preparing glyceryl monostearate (GMS) nanoparticles using a temperature-modulated solidification process. The technique was reproducible and prepared nanoparticles without the need of organic solvents. An anticancer agent, 5-fluorouracil (5-FU), was incorporated in the SLNs. The SLNs were characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), infrared spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), drug encapsulation efficiency, in vitro drug release, and in vitro cell viability studies. Particle size of the SLN dispersion was below 100 nm, and that of redispersed lyophilizates was ~500 nm. DSC and infrared spectroscopy suggested that the degree of crystallinity did not decrease appreciably when compared to GMS. TEM and AFM images showed well-defined spherical to oval particles. The drug encapsulation efficiency was found to be approximately 46%. In vitro drug release studies showed that 80% of the encapsulated drug was released within 1 h. In vitro cell cultures were biocompatible with blank SLNs but demonstrated concentration-dependent changes in cell viability to 5-FU-loaded SLNs. The 5-FU-loaded SLNs can potentially be utilized in an anticancer drug delivery system.

Microencapsulation of vitamin e from palm fatty acid distillate with galactomannan and gum acacia using spray drying method

NASA Astrophysics Data System (ADS)

Tarigan, J. Br.; Kaban, J.; Zulmi, R.

2018-02-01

Vitamin E from palm fatty acid distillate (PFAD) has been encapsulated using spray drying method with gum acacia (GA) and mixed of galactomannan from Arenga pinnata (GAP) with GA as encapsulating agent. Composite films with thickness vary from 0.542 - 0.779 mm were prepared by incorporating vitamin E onto matrix of GA (7 g) with various concentration of GAP (0.1; 0.2; 0.3 and 0.4 g). The film obtained from 0.2 g GAP and 1.3 g vitamin E showed better compatibility and have viscosity similar with standard (ISO 9001:2008 and ISO 22000:2005). That composition was used for spray drying method rendering micro-particle size 11 µm and the particle had spherical shape. Although the increment of GAP decreasing moisture content and the particle size from 16 µm to 11 µm, the yield of microcapsule, encapsulation efficiency, the amount of vitamin E absorbed and oxidation stability of vitamin E were increased.

Encapsulation of ascorbyl palmitate in chitosan nanoparticles by oil-in-water emulsion and ionic gelation processes.

PubMed

Yoksan, Rangrong; Jirawutthiwongchai, Jatesuda; Arpo, Kridsada

2010-03-01

The encapsulation of ascorbyl palmitate (AP) in chitosan particles was carried out by droplet formation via an oil-in-water emulsion, followed by droplet solidification via ionic gelation using sodium triphosphate pentabasic (TPP) as a cross-linking agent. The success of AP encapsulation was confirmed by FT-IR, UV-vis spectrophotometry, TGA, and XRD techniques. The obtained AP-loaded chitosan particles were spherical in shape with an average diameter of 30-100nm as observed by SEM and TEM. Loading capacity (LC) and encapsulation efficiency (EE) of AP in the nanoparticles were about 8-20% and 39-77%, respectively, when the initial AP concentration was in the range of 25-150% (w/w) of chitosan. Augmentation of the initial AP concentration led to an increase of LC and a reduction of EE. The amount of AP released from the nanoparticles in ethanol and tris buffer (pH approximately 8.0) increased with increasing LC and decreasing TPP concentration.

Selective encapsulation by Janus particles

NASA Astrophysics Data System (ADS)

Li, Wei; Ruth, Donovan; Gunton, James D.; Rickman, Jeffrey M.

2015-06-01

We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored, as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.

Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

NASA Technical Reports Server (NTRS)

Pearman, Benjamin Pieter; Li, Wenyan; Buhrow, Jerry; Zhang, Xuejun; Surma, Jan; Fitzpatrick, Lilly; Montgomery, Eliza; Calle, Luz Marina

2014-01-01

Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.

Formation of enriched black tea extract loaded chitosan nanoparticles via electrospraying

NASA Astrophysics Data System (ADS)

Hammond, Samuel James

Creating nanoparticles of beneficial nutraceuticals and pharmaceuticals has had a large surge of research due to the enhancement of absorption and bioavailability by decreasing their size. One of these ways is by electrohydrodynamic atomization, also known as electrospraying. In general, this novel process is done by forcing a liquid through a capillary nozzle and which is subjected to an electrical field. While there are different ways to create nanoparticles, the novel method of electrospraying can be beneficial over other types of nanoparticle formation. Reasons include high control over particle size and distribution by altering electrospray parameters (voltage, flow rate, distance, and time), higher encapsulation efficiency than other methods, and also it is a one step process without exposure to extreme conditions (Gomez-Estaca et. al. 2012, Jaworek and Sobcyzk 2008). The current study aimed to create a chitosan encapsulated theaflavin-2 enriched black tea extract (BTE) nanoparticles via electrospraying. The first step of this process was to create the smallest chitosan nanoparticles possible by altering the electrospray parameters and the chitosan-acetic acid solution parameters. The solution properties altered include chitosan molecular weight, acetic acid concentration, and chitosan concentration. Specifically, the electrospray parameters such as voltage, flow rate and distance from syringe to collector are the most important in determining particle size. After creating the smallest chitosan particles, the TF-2 enriched black tea extract was added to the chitosan-acetic acid solution to be electrosprayed. The particles were assessed with the following procedures: Atomic force microscopy (AFM) and scanning electron microscopy (SEM) for particle morphology and size, and loading efficiency with ultraviolet--visible spectrophotometer (UV-VIS). Chitosan-BTE nanoparticles were successfully created in a one step process. Diameter of the particles on average ranged from 255 nm to 560 nm. Encapsulation efficiency was above 95% for all but one sample set. Future work includes MTT assay and cellular uptake.

Hydrophobic ion pairing of a minocycline/Ca(2+)/AOT complex for preparation of drug-loaded PLGA nanoparticles with improved sustained release.

PubMed

Holmkvist, Alexander Dontsios; Friberg, Annika; Nilsson, Ulf J; Schouenborg, Jens

2016-02-29

Polymeric nanoparticles is an established and efficient means to achieve controlled release of drugs. Incorporation of minocycline, an antibiotic with anti-inflammatory and neuroprotective properties, into biodegradable nanoparticles may therefore provide an efficient means to combat foreign body reactions to implanted electrodes in the brain. However, minocycline is commonly associated with poor encapsulation efficiencies and/or fast release rates due to its high solubility in water. Moreover, minocycline is unstable under conditions of low and high pH, heat and exposure to light, which exacerbate the challenges of encapsulation. In this work drug loaded PLGA nanoparticles were prepared by a modified emulsification-solvent-diffusion technique and characterized for size, drug encapsulation and in vitro drug release. A novel hydrophobic ion pair complex of minocycline, Ca(2+) ions and the anionic surfactant AOT was developed to protect minocycline from degradation and prolong its release. The optimized formulation resulted in particle sizes around 220 nm with an entrapment efficiency of 43% and showed drug release over 30 days in artificial cerebrospinal fluid. The present results constitute a substantial increase in release time compared to what has hitherto been achieved for minocycline and indicate that such particles might provide useful for sustained drug delivery in the CNS. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Selective encapsulation by Janus particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei, E-mail: wel208@mrl.ucsb.edu; Ruth, Donovan; Gunton, James D.

2015-06-28

We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored,more » as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.« less

Antiproliferative effect of Antrodia camphorata polysaccharides encapsulated in chitosan-silica nanoparticles strongly depends on the metabolic activity type of the cell line

NASA Astrophysics Data System (ADS)

Kong, Zwe-Ling; Chang, Jenq-Sheng; Chang, Ke Liang B.

2013-09-01

Chitosan molecules interact with silica and encapsulate the Antrodia camphorata extract (ACE) polysaccharides to form composite nanoparticles. The nanoparticle suspensions of ACE polysaccharides encapsulated in silica-chitosan and silica nanoparticles approach an average particle size of 210 and 294 nm in solution, respectively. The encapsulation efficiencies of ACE polysaccharides are 66 and 63.5 %, respectively. Scanning electron micrographs confirm the formation of near-spherical nanoparticles. ACE polysaccharides solution had better antioxidative capability than ACE polysaccharides encapsulated in silica or silica-chitosan nanoparticles suspensions. The antioxidant capacity of nanoparticles increases with increasing dissolution time. The antitumor effects of ACE polysaccharides, ACE polysaccharides encapsulated in silica, or silica-chitosan nanoparticles increased with increasing concentration of nanoparticles. This is the first report demonstrating the potential of ACE polysaccharides encapsulated in chitosan-silica nanoparticles for cancer chemoprevention. Furthermore, this study suggests that antiproliferative effect of nanoparticle-encapsulated bioactive could significantly depend on the metabolic activity type of the cell line.

Curcumin liposomes prepared with milk fat globule membrane phospholipids and soybean lecithin.

PubMed

Jin, Hong-Hao; Lu, Qun; Jiang, Jian-Guo

2016-03-01

Using thin film ultrasonic dispersion method, the curcumin liposomes were prepared with milk fat globule membrane (MFGM) phospholipids and soybean lecithins, respectively, to compare the characteristics and stability of the 2 curcumin liposomes. The processing parameters of curcumin liposomes were investigated to evaluate their effects on the encapsulation efficiency. Curcumin liposomes were characterized in terms of size distribution, ζ-potential, and in vitro release behavior, and then their storage stability under various conditions was evaluated. The curcumin liposomes prepared with MFGM phospholipids had an encapsulation efficiency of about 74%, an average particle size of 212.3 nm, and a ζ-potential of -48.60 mV. The MFGM liposomes showed higher encapsulation efficiency, smaller particle size, higher absolute value of ζ-potential, and slower in vitro release than soybean liposomes. The retention rate of liposomal curcumin was significantly higher than that of free curcumin. The stability of the 2 liposomes under different pH was almost the same, but MFGM liposomes displayed a slightly higher stability than soybean liposomes under the conditions of Fe(3+), light, temperature, oxygen, and relative humidity. In conclusion, MFGM phospholipids have potential advantages in the manufacture of curcumin liposomes used in food systems. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Preparation, characterization, and in vitro release study of albendazole-encapsulated nanosize liposomes

PubMed Central

Panwar, Preety; Pandey, Bhumika; Lakhera, P C; Singh, K P

2010-01-01

The purpose of the present study was to formulate effective and controlled release albendazole liposomal formulations. Albendazole, a hydrophobic drug used for the treatment of hydatid cysts, was encapsulated in nanosize liposomes. Rapid evaporation method was used for the preparation of albendazole-encapsulated conventional and PEGylated liposomes consisting of egg phosphatidylcholine (PC) and cholesterol (CH) in the molar ratios of (6:4) and PC:CH: polyethylene glycol (PEG) (5:4:1), respectively. In this study, PEGylated and conventional liposomes containing albendazole were prepared and their characteristics, such as particle size, encapsulation efficiency, and in vitro drug release were investigated. The drug encapsulation efficiency of PEGylated and conventional liposomes was 81% and 72%, respectively. The biophysical characterization of both conventional and PEG-coated liposomes were done by transmission electron microscopy and UV-vis spectrophotometry. Efforts were made to study in vitro release of albendazole. The drug release rate showed decrease in albendazole release in descending order: free albendazole, albendazole-loaded conventional liposomes, and least with albendazole-loaded PEG-liposomes. Biologically relevant vesicles were prepared and in vitro release of liposome-entrapped albendazole was determined. PMID:20309396

Photoresponsive cross-linked polymeric particles for phototriggered burst release.

PubMed

Wang, Zhen; Yu, Lili; Lv, Cong; Wang, Peng; Chen, Yedong; Tang, Xinjing

2013-01-01

We synthesized a series of cross-linked photoresponsive polymeric particles with photolabile monomers and cross-linkers through miniemulsion polymerization. These particles are quite stable in dark, while light irradiation caused the breakage of particles and the efficient release of encapsulated contents up to 95% based on Nile red fluorescence. Photoswitches of particle systems were confirmed by fluorescence spectroscopy, SEM and colorimetry. Particle uptake and triggered release in RAW264.7 cells were confirmed by fluorescein diacetate loaded particles. © 2013 The Authors. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

Encapsulation of lutein in liposomes using supercritical carbon dioxide.

PubMed

Zhao, Lisha; Temelli, Feral; Curtis, Jonathan M; Chen, Lingyun

2017-10-01

Liposomes loaded with lutein were prepared utilizing supercritical carbon dioxide (SC-CO 2 ). The effects of pressure, depressurization rate, temperature and lutein-to-lipid ratio on particle size distribution, zeta potential, encapsulation efficiency (EE), bioactive loading, morphology, phase transition and crystallinity were investigated. Liposomes prepared by the SC-CO 2 method had a particle size of 147.6±1.9nm-195.4±2.3nm, an encapsulation efficiency of 56.7±0.7%-97.0±0.8% and a zeta potential of -54.5±1.2mV to -61.7±0.6mV. A higher pressure (200-300bar) and depressurization rate (90-200bar/min) promoted a higher encapsulation of lutein whereas the lutein-to-lipid ratio had the dominant effect on the morphology of vesicles along with size distribution and EE. X-ray diffraction data implied a substantial drop in the crystallinity of lutein upon its redistribution in the liposome membranes. Differential scanning calorimetry indicated a broadened phase transition upon the simultaneous rearrangement of lutein and phospholipid molecules into liposomal vesicles. The SC-CO 2 method resulted in particle characteristics highly associated with the ability of CO 2 to disperse phospholipids and lutein molecules. It offers a promising approach to use dense phase CO 2 to homogenize hydrophobic or amphiphilic aggregates suspended in an aqueous medium and regulate the vesicular characteristics via pressure and depressurization rate. The SC-CO 2 method has potential for scalable production of liposomal nanovesicles with desirable characteristics and free of organic solvents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Delivery of kinesin spindle protein targeting siRNA in solid lipid nanoparticles to cellular models of tumor vasculature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ying, Bo; Campbell, Robert B., E-mail: robert.campbell@mcphs.edu

2014-04-04

Highlights: • siRNA-lipid nanoparticles are solid particles not lipid bilayers with aqueous core. • High, but not low, PEG content can prevent nanoparticle encapsulation of siRNA. • PEG reduces cellular toxicity of cationic nanoparticles in vitro. • PEG reduces zeta potential while improving gene silencing of siRNA nanoparticles. • Kinesin spindle protein can be an effective target for tumor vascular targeting. - Abstract: The ideal siRNA delivery system should selectively deliver the construct to the target cell, avoid enzymatic degradation, and evade uptake by phagocytes. In the present study, we evaluated the importance of polyethylene glycol (PEG) on lipid-based carriermore » systems for encapsulating, and delivering, siRNA to tumor vessels using cellular models. Lipid nanoparticles containing different percentage of PEG were evaluated based on their physical chemical properties, density compared to water, siRNA encapsulation, toxicity, targeting efficiency and gene silencing in vitro. siRNA can be efficiently loaded into lipid nanoparticles (LNPs) when DOTAP is included in the formulation mixture. However, the total amount encapsulated decreased with increase in PEG content. In the presence of siRNA, the final formulations contained a mixed population of particles based on density. The major population which contains the majority of siRNA exhibited a density of 4% glucose, and the minor fraction associated with a decreased amount of siRNA had a density less than PBS. The inclusion of 10 mol% PEG resulted in a greater amount of siRNA associated with the minor fraction. Finally, when kinesin spindle protein (KSP) siRNA was encapsulated in lipid nanoparticles containing a modest amount of PEG, the proliferation of endothelial cells was inhibited due to the efficient knock down of KSP mRNA. The presence of siRNA resulted in the formation of solid lipid nanoparticles when prepared using the thin film and hydration method. LNPs with a relatively modest amount of PEG can sufficiently encapsulate siRNA, improve cellular uptake and the efficiency of gene silencing.« less

Stability of niosomes with encapsulated vitamin D3 and ferrous sulfate generated using a novel supercritical carbon dioxide method.

PubMed

Wagner, Michael E; Spoth, Katherine A; Kourkoutis, Lena F; Rizvi, Syed S H

2016-12-01

Niosomes were prepared using a novel supercritical carbon dioxide based method to simultaneously encapsulate ferrous sulfate and vitamin D3 as hydrophilic and hydrophobic cargo, respectively. Vesicle particle size was determined to be bimodal with peak diameters of 1.44 ± 0.16 μm and 7.21 ± 0.64 μm, with the smaller peak comprising 98.8% of the total niosomal volume. Encapsulation efficiency of ferrous sulfate was 25.1 ± 0.2% and encapsulation efficiency of vitamin D3 was 95.9 ± 1.47%. Physical stability of the produced niosomes was assessed throughout a storage period of 21 days. Niosomes showed good physical stability at 20 °C, but storage at 4 °C showed an initial burst release, indicating possible rupture of the niosomal membrane. The Korsmeyer-Peppas equation was used to model the release of ferrous sulfate over time at both storage temperatures.

Osmotic-pressure-controlled concentration of colloidal particles in thin-shelled capsules

NASA Astrophysics Data System (ADS)

Kim, Shin-Hyun; Park, Jin-Gyu; Choi, Tae Min; Manoharan, Vinothan N.; Weitz, David A.

2014-01-01

Colloidal crystals are promising structures for photonic applications requiring dynamic control over optical properties. However, for ease of processing and reconfigurability, the crystals should be encapsulated to form ‘ink’ capsules rather than confined in a thin film. Here we demonstrate a class of encapsulated colloidal photonic structures whose optical properties can be controlled through osmotic pressure. The ordering and separation of the particles within the microfluidically created capsules can be tuned by changing the colloidal concentration through osmotic pressure-induced control of the size of the individual capsules, modulating photonic stop band. The rubber capsules exhibit a reversible change in the diffracted colour, depending on osmotic pressure, a property we call osmochromaticity. The high encapsulation efficiency and capsule uniformity of this microfluidic approach, combined with the highly reconfigurable shapes and the broad control over photonic properties, make this class of structures particularly suitable for photonic applications such as electronic inks and reflective displays.

Imaging efficiency of an X-ray contrast agent-incorporated polymeric microparticle.

PubMed

Ahn, Sungsook; Jung, Sung Yong; Lee, Jin Pyung; Lee, Sang Joon

2011-01-01

Biocompatible polymeric encapsulants have been widely used as a delivery vehicle for a variety of drugs and imaging agents. In this study, X-ray contrast agent (iopamidol) is encapsulated into a polymeric microparticle (polyvinyl alcohol) as a particulate flow tracer in synchrotron X-ray imaging system. The physical properties of the designed microparticles are investigated and correlated with enhancement in the imaging efficiency by experimental observation and theoretical interpretation. The X-ray absorption ability of the designed microparticle is assessed by Beer-Lambert-Bouguer law. Particle size, either in dried state or in solvent, primarily dominates the X-ray absorption ability under the given condition, thus affecting imaging efficiency of the designed X-ray contrast flow tracers. Copyright © 2011 John Wiley & Sons, Ltd.

Nano and microparticle engineering of water insoluble drugs using a novel spray-drying process.

PubMed

Schafroth, Nina; Arpagaus, Cordin; Jadhav, Umesh Y; Makne, Sushil; Douroumis, Dennis

2012-02-01

In the current study nano and microparticle engineering of water insoluble drugs was conducted using a novel piezoelectric spray-drying approach. Cyclosporin A (CyA) and dexamethasone (DEX) were encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) grades of different molecular weights. Spray-drying studies carried out with the Nano Spray Dryer B-90 employed with piezoelectric driven actuator. The processing parameters including inlet temperature, spray mesh diameter, sample flow rate, spray rate, applied pressure and sample concentration were examined in order to optimize the particle size and the obtained yield. The process parameters and the solute concentration showed a profound effect on the particle engineering and the obtained product yield. The produced powder presented consistent and reproducible spherical particles with narrow particle size distribution. Cyclosporin was found to be molecularly dispersed while dexamethasone was in crystalline state within the PLGA nanoparticles. Further evaluation revealed excellent drug loading, encapsulation efficiency and production yield. In vitro studies demonstrated sustained release patterns for the active substances. This novel spray-drying process proved to be efficient for nano and microparticle engineering of water insoluble active substances. Copyright © 2011 Elsevier B.V. All rights reserved.

Cinnamomum casia Extract Encapsulated Nanochitosan as Antihypercholesterol

NASA Astrophysics Data System (ADS)

Ngadiwiyana; Purbowatiningrum; Fachriyah, Enny; Ismiyarto

2017-02-01

Atherosclerosis vascular disease with clinical manifestations such as cardiovascular disease and stroke are the leading cause of death in Indonesia. One solution to these problems is a natural antihypercholesterol medicine by utilizing Cinnamomum casia extract. However, the use of natural extracts to lower blood cholesterol levels do not provide optimal results because it is possible that the active components of extract have been degraded/damaged during the absorption process. So that, we need to do the research to get a combination of chitosan nanoparticles-Cinnamomum casia. extract as a compound which has an antihypercholesterol activity through the in vitro study. Modification of natural extracts encapsulated nanochitosan be a freshness in this study, which were conducted using the method of inclusion. The combination of both has the dual function of protecting the natural extracts from degradation and deliver the natural extracts to the target site. Analysis of nanochitosan using the Particle Size Analyzer (PSA) shows the particle size of synthesis product that is equal to 64.9 nm. Encapsulation efficiency of Cinnamomum casia extract-Chitosan Nanoparticles known through UV-VIS spectrophotometry test and obtained the efficiency encapsulation percentage of 84.93%. Zeta Potential at 193,3 mv that chitosan appropriate for a delivery drug. Antihypercholesterol activity tested in vitro assay that showed the extract-nanoparticle chitosan in concentration 150 ppm gave the highest cholesterol decreasing level in the amount of 49.66% w/v. So it can be concluded that Cinnamomum casia extract can be encapsulated in nanoparticles of chitosan and proved that it has a cholesterol-lowering effect through the in vitro study.

Novel Biobased Sodium Shellac for Wrapping Disperse Multiscale Emulsion Particles.

PubMed

Luo, Qingming; Li, Kai; Xu, Juan; Li, Kun; Zheng, Hua; Liu, Lanxiang; Zhang, Hong; Sun, Yanlin

2016-12-14

As a result of amphipathic oligomers driven by different forces including hydrophobic interaction, electrostatic interaction, H-bond, and heat, multiscale emulsion particles can be wrapped. In this paper we attempted to use sodium shellac as a novel biobased wrapping material. The H + , Ca + , and spray-drying methods were employed to solidify the complex vitamin E (VE) emulsion with sodium shellac to fabricate the beads. The VE loading and encapsulation efficiency were used to evaluate the wrapping process. The results show that the microscale VE emulsion particles could easily be wrapped by these three means. However, due to the high solid content of the nanoscale emulsion particles, it was difficult to wrap them by spray-drying method. The beads solidified by H + had higher VE loading and encapsulation efficiency than those solidified by other methods and even grabbed the hydrophobic molecule VE from the emulsion micelles. At an R VS of 1:4, these two parameters, which are obtained by the nanoscale emulsion particle wrapping process, could reach 18.9 and 64.3% supported by the single driving force of hydrophobic interaction. Above all, this research introduced a novel wrapping material driven by different forces that can aggregate and wrap the emulsion micelles. It can be widely used in the medical, food, and cosmetics industries.

Coencapsulation of (-)-Epigallocatechin-3-gallate and Quercetin in Particle-Stabilized W/O/W Emulsion Gels: Controlled Release and Bioaccessibility.

PubMed

Chen, Xing; McClements, David Julian; Wang, Jian; Zou, Liqiang; Deng, Sumeng; Liu, Wei; Yan, Chi; Zhu, Yuqing; Cheng, Ce; Liu, Chengmei

2018-04-11

Particle-stabilized W 1 /O/W 2 emulsion gels were fabricated using a two-step procedure: ( i) a W 1 /O emulsion was formed containing saccharose (for osmotic stress balance) and gelatin (as a gelling agent) in the aqueous phase and polyglycerol polyricinoleate (a lipophilic surfactant) in the oil phase; ( ii) this W 1 /O emulsion was then homogenized with another water phase (W 2 ) containing wheat gliadin nanoparticles (hydrophilic emulsifier). The gliadin nanoparticles in the external aqueous phase aggregated at pH 5.5, which led to the formation of particle-stabilized W 1 /O/W 2 emulsion gels with good stability to phase separation. These emulsion gels were then used to coencapsulate a hydrophilic bioactive (epigallocatechin-3-gallate, EGCG) in the internal aqueous phase (encapsulation efficiency = 65.5%) and a hydrophobic bioactive (quercetin) in the oil phase (encapsulation efficiency = 97.2%). The emulsion gels improved EGCG chemical stability and quercetin solubility under simulated gastrointestinal conditions, which led to a 2- and 4-fold increase in their effective bioaccessibility, respectively.

Effect of squalane on mebendazole-loaded Compritol® nanoparticles.

PubMed

Graves, Richard A; Ledet, Grace A; Nation, Cedric A; Pramar, Yashoda V; Bostanian, Levon A; Mandal, Tarun K

2015-01-01

The objective of this study is to develop nanostructured lipid formulations of Compritol for the delivery of mebendazole. The formulations were prepared with Compritol 888 ATO, squalane, and Pluronic F68. Nine batches with different amounts of modifier, squalane, and drug were prepared. The formulations were characterized by evaluating particle size, morphology, and zeta potential. The thermal properties of the formulations were analyzed by differential scanning calorimetry (DSC). The encapsulation efficiency of each formulation and the drug release rates from each formulation were quantified by UPLC. The particles were spherical and had median particle sizes between 300 and 600 nm (50th percentile). A linear relationship was observed between Compritol/squalane composition and the melting point of the mixture. The DSC scans of the formulations revealed some recrystallization of the drug from the formulations, and the amount of recrystallization correlated with the amount of squalane in the formulation. Approximately, 70% efficiency of encapsulation was observed in the formulations with 30% (w/w) squalane, and these formulations also had faster dissolution rates compared to the other formulations. Overall, the formulations with 30% squalane are the preferred formulation for future testing.

Novel method of niosome generation using supercritical carbon dioxide part I: process mechanics.

PubMed

Wagner, Michael E; Rizvi, Syed S H

2015-01-01

A novel method for the production of non-ionic surfactant vesicles (niosomes) using an rapid expansion of supercritical solution (RESS)-based process coupled with a gas ejector is presented along with an investigation of parameters affecting niosome morphology, size and encapsulation efficiency of a 0.2 M D-glucose solution in Tris buffer at physiological pH. The solubility of the non-ionic surfactant polyoxyethylene(4) sorbitan monostearate in SC-CO2 was determined at three pressures (10, 15 and 20 MPa) and three temperatures (40, 50 and 60 °C). Mole fraction of Tween61 in the vapor phase increased with pressure at 40 °C, but did not change with pressure at 50 or 60 °C. Solubility data were correlated using the Peng-Robinson equation of state (PREOS) with the Panagiotopoulos and Reid mixing rule. Vesicles were either multilamellar or unilamellar, depending on the degree of precipitation of the lipid formulation at the point of aqueous cargo introduction. Vesicle particle size distributions were bimodal, with the 80-99% of the liposomal volume contributed niosomes ranging in size from 3 to 7 μm and the remaining niosomes ranging from 239 to 969 nm, depending on the system configuration. Encapsulation efficiency as high as 28% using the gas ejector to introduce the glucose cargo solution was achieved. Vesicle particle size and encapsulation efficiency were shown to be dependent on cargo droplet formation.

One-to-one encapsulation based on alternating droplet generation

NASA Astrophysics Data System (ADS)

Hirama, Hirotada; Torii, Toru

2015-10-01

This paper reports the preparation of encapsulated particles as models of cells using an alternating droplet generation encapsulation method in which the number of particles in a droplet is controlled by a microchannel to achieve one-to-one encapsulation. Using a microchannel in which wettability is treated locally, the fluorescent particles used as models of cells were successfully encapsulated in uniform water-in-oil-in-water (W/O/W) emulsion droplets. Furthermore, 20% of the particle-containing droplets contained one particle. Additionally, when a surfactant with the appropriate properties was used, the fluorescent particles within each inner aqueous droplet were enclosed in the merged droplet by spontaneous droplet coalescence. This one-to-one encapsulation method based on alternating droplet generation could be used for a variety of applications, such as high-throughput single-cell assays, gene transfection into cells or one-to-one cell fusion.

One-to-one encapsulation based on alternating droplet generation.

PubMed

Hirama, Hirotada; Torii, Toru

2015-10-21

This paper reports the preparation of encapsulated particles as models of cells using an alternating droplet generation encapsulation method in which the number of particles in a droplet is controlled by a microchannel to achieve one-to-one encapsulation. Using a microchannel in which wettability is treated locally, the fluorescent particles used as models of cells were successfully encapsulated in uniform water-in-oil-in-water (W/O/W) emulsion droplets. Furthermore, 20% of the particle-containing droplets contained one particle. Additionally, when a surfactant with the appropriate properties was used, the fluorescent particles within each inner aqueous droplet were enclosed in the merged droplet by spontaneous droplet coalescence. This one-to-one encapsulation method based on alternating droplet generation could be used for a variety of applications, such as high-throughput single-cell assays, gene transfection into cells or one-to-one cell fusion.

Encapsulated Pseudomonas putida for phenol biodegradation: Use of a structural membrane for construction of a well-organized confined particle.

PubMed

Kurzbaum, Eyal; Raizner, Yasmin; Cohen, Oded; Suckeveriene, Ran Y; Kulikov, Anatoly; Hakimi, Ben; Iasur Kruh, Lilach; Armon, Robert; Farber, Yair; Menashe, Ofir

2017-09-15

Phenols are toxic byproducts from a wide range of industry sectors. If not treated, they form effluents that are very hazardous to the environment. This study presents the use of a Pseudomonas putida F1 culture encapsulated within a confined environment particle as an efficient technique for phenol biodegradation. The innovative encapsulation technique method, named the "Small Bioreactor Platform" (SBP) technology, enables the use of a microfiltration membrane constructed as a physical barrier for creating a confined environment for the encapsulated culture. The phenol biodegradation rate of the encapsulated culture was compared to its suspended state in order to evaluate the effectiveness of the encapsulation technique for phenol biodegradation. A maximal phenol biodegradation rate (q) of 2.12/d was exhibited by encapsulated P. putida at an initial phenol concentration of 100 mg/L. The biodegradation rate decreased significantly at lower and higher initial phenol concentrations of 50 and up to 3000 mg/L, reaching a rate of 0.1018/d. The results also indicate similar and up to double the degradation rate between the two bacterial states (encapsulated vs. suspended). High resolution scanning electron microscopy images of the SBP capsule's membrane morphology demonstrated a highly porous microfiltration membrane. These results, together with the long-term activity of the SBP capsules and verification that the culture remains pure after 60 days using 16S rRNA gene phylogenetic affiliation tests, provide evidence for a successful application of this new encapsulation technique for bioaugmentation of selected microbial cultures in water treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

High loading efficiency and sustained release of siRNA encapsulated in PLGA nanoparticles: quality by design optimization and characterization.

PubMed

Cun, Dongmei; Jensen, Ditte Krohn; Maltesen, Morten Jonas; Bunker, Matthew; Whiteside, Paul; Scurr, David; Foged, Camilla; Nielsen, Hanne Mørck

2011-01-01

Poly(DL-lactide-co-glycolide acid) (PLGA) is an attractive polymer for delivery of biopharmaceuticals owing to its biocompatibility, biodegradability and outstanding controlled release characteristics. The purpose of this study was to understand and define optimal parameters for preparation of small interfering RNA (siRNA)-loaded PLGA nanoparticles by the double emulsion solvent evaporation method and characterize their properties. The experiments were performed according to a 2(5-1) fractional factorial design based on five independent variables: The volume ratio between the inner water phase and the oil phase, the PLGA concentration, the sonication time, the siRNA load and the amount of acetylated bovine serum albumin (Ac-BSA) in the inner water phase added to stabilize the primary emulsion. The effects on the siRNA encapsulation efficiency and the particle size were investigated. The most important factors for obtaining an encapsulation efficiency as high as 70% were the PLGA concentration and the volume ratio whereas the size was mainly affected by the PLGA concentration. The viscosity of the oil phase was increased at high PLGA concentration, which explains the improved encapsulation by stabilization of the primary emulsion and reduction of siRNA leakage to the outer water phase. Addition of Ac-BSA increased the encapsulation efficiency at low PLGA concentrations. The PLGA matrix protected siRNA against nuclease degradation, provided a burst release of surface-localized siRNA followed by a triphasic sustained release for two months. These results enable careful understanding and definition of optimal process parameters for preparation of PLGA nanoparticles encapsulating high amounts of siRNA with immediate and long-term sustained release properties. Copyright © 2010 Elsevier B.V. All rights reserved.

Sustained release and permeation of timolol from surface-modified solid lipid nanoparticles through bioengineered human cornea.

PubMed

Attama, A A; Reichl, S; Müller-Goymann, C C

2009-08-01

The aim of the study was to formulate and evaluate surface-modified solid lipid nanoparticles sustained delivery system of timolol hydrogen maleate, a prototype ocular drug using a human cornea construct. Surface-modified solid lipid nanoparticles containing timolol with and without phospholipid were formulated by melt emulsification with high-pressure homogenization and characterized by particle size, wide-angle X-ray diffraction, encapsulation efficiency, and in vitro drug release. Drug transport studies through cornea bioengineered from human donor cornea cells were carried out using a modified Franz diffusion cell and drug concentration analyzed by high-performance liquid chromatography. Results show that surface-modified solid lipid nanoparticles possessed very small particles (42.9 +/- 0.3 nm, 47.2 +/- 0.3 nm, 42.7 +/- 0.7 nm, and 37.7 +/- 0.3 nm, respectively for SM-SLN 1, SM-SLN 2, SM-SLN 3, and SM-SLN 4) with low polydispersity indices, increased encapsulation efficiency (> 44%), and sustained in vitro release compared with unmodified lipid nanoparticles whose particles were greater than 160 nm. Permeation of timolol hydrogen maleate from the surface-modified lipid nanoparticles across the cornea construct was sustained compared with timolol hydrogen maleate solution in distilled water. Surface-modified solid lipid nanoparticles could provide an efficient way of improving ocular bioavailability of timolol hydrogen maleate.

Targeted Delivery of Glucan Particle Encapsulated Gallium Nanoparticles Inhibits HIV Growth in Human Macrophages

PubMed Central

Soto, Ernesto R.; O'Connell, Olivia; Dikengil, Fusun; Peters, Paul J.; Clapham, Paul R.

2016-01-01

Glucan particles (GPs) are hollow, porous 3–5 μm microspheres derived from the cell walls of Baker's yeast (Saccharomyces cerevisiae). The 1,3-β-glucan outer shell provides for receptor-mediated uptake by phagocytic cells expressing β-glucan receptors. GPs have been used for macrophage-targeted delivery of a wide range of payloads (DNA, siRNA, protein, small molecules, and nanoparticles) encapsulated inside the hollow GPs or bound to the surface of chemically derivatized GPs. Gallium nanoparticles have been proposed as an inhibitory agent against HIV infection. Here, macrophage targeting of gallium using GPs provides for more efficient delivery of gallium and inhibition of HIV infection in macrophages compared to free gallium nanoparticles. PMID:27965897

Hydrogel Nanoparticles from Supercritical Technology for Pharmaceutical and Seismological Applications

NASA Astrophysics Data System (ADS)

Hemingway, Melinda Graham

This research focuses on hydrogel nanoparticle formation using miniemulsion polymerization and supercritical carbon dioxide. Hydrogel nanopowder is produced by a novel combination of inverse miniemulsion polymerization and supercritical drying (MPSD) methods. Three drying methods of miniemulsions are examined: (1) a conventional freeze drying technique, and (2) two supercritical drying techniques: (2a) supercritical fluid injection into miniemulsions, and (2b) the polymerized miniemulsion injection into supercritical fluid. Method 2b can produce non-agglomerated hydrogel nanoparticles that are free of solvent or surfactant (Chapter 2). The optimized MPSD method was applied for producing an extended release drug formulation with mucoadhesive properties. Drug nanoparticles of mesalamine, were produced using supercritical antisolvent technology and encapsulation within two hydrogels, polyacrylamide and poly(acrylic acid-co-acrylamide). The encapsulation efficiency and release profile of drug nanoparticles is compared with commercial ground mesalamine particles. The loading efficiency is influenced by morphological compatibility (Chapter 3). The MPSD method was extended for encapsulation of zinc oxide nanoparticles for UV protection in sunscreens (Chapter 4). ZnO was incorporated into the inverse miniemulsion during polymerization. The effect of process parameters are examined on absorbency of ultraviolet light and transparency of visible light. For use of hydrogel nanoparticles in a seismological application, delayed hydration is needed. Supercritical methods extend MPSD so that a hydrophobic coating can be applied on the particle surface (Chapter 5). Multiple analysis methods and coating materials were investigated to elucidate compatibility of coating material to polyacrylamide hydrogel. Coating materials of poly(lactide), poly(sulphone), poly(vinyl acetate), poly(hydroxybutyrate), Geluice 50-13, Span 80, octadecyltrichlorosilane, and perfluorobutane sulfate (PFBS) were tested, out of which Gelucire, perfluorobutane sulfate, and poly(vinyl acetate) materials were able to provide some coating and perfluorobutane sulfate, poly(lactide), poly(vinyl acetate) delayed hydration of hydrogel particles, but not to a sufficient extent. The interactions of the different materials with the hydrogel are examined based on phenomena observed during the production processes and characterization of the particles generated. This work provides understanding into the interactions of polyacrylamide hydrogel particles both internally by encapsulation and externally by coating.

Intravenous administration of brain-targeted stable nucleic acid lipid particles alleviates Machado-Joseph disease neurological phenotype.

PubMed

Conceição, Mariana; Mendonça, Liliana; Nóbrega, Clévio; Gomes, Célia; Costa, Pedro; Hirai, Hirokazu; Moreira, João Nuno; Lima, Maria C; Manjunath, N; Pereira de Almeida, Luís

2016-03-01

Others and we showed that RNA interference holds great promise for the treatment of dominantly inherited neurodegenerative disorders such as Machado-Joseph disease (MJD), for which there is no available treatment. However, successful experiments involved intracranial administration of viral vectors and there is a need for a safer and less invasive procedure. In this work, we successfully generated stable nucleic acid lipid particles (SNALPs), incorporating a short peptide derived from rabies virus glycoprotein (RVG-9r) and encapsulating small interfering RNAs (siRNAs), which can target mutant ataxin-3. The developed formulation exhibited important features that make it adequate for systemic administration: high encapsulation efficiency of siRNAs, ability to protect the encapsulated siRNAs, appropriate and homogeneous particle size distribution. Following optimization of the formulation and in vitro validation of its efficacy to silence the MJD-causing protein - mutant ataxin-3 - in neuronal cells, in vivo experiments showed that intravenous administration of RVG-9r-targeted SNALPs efficiently silenced mutant ataxin-3 reducing neuropathology and motor behavior deficits in two mouse models of MJD. To our knowledge, this is the first report showing beneficial impact of a non-viral gene silencing strategy in MJD and the first time that a non-invasive systemic administration proved to be beneficial on a polyglutamine disorder. Our study opens new avenues towards MJD therapy that can also be applied to other neurodegenerative diseases linked to the production of pathogenic proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physical Immobilization Liposomes in Uniform Zwitterionic Microgel Particles Fabricated in Microcapillary Device

NASA Astrophysics Data System (ADS)

Jeong, Eun Seon; Byun, Aram; Kim, Jin Woong

2014-03-01

Lipid molecules have both hydrophilic and hydrophobic properties. Since their packing parameter ranges from 0.5 to 1, they self-assemble to form a vesicle structure, liposome. Thanks to the vesicle structure, liposome is able to encapsulate both hydrophilic and hydrophobic active ingredients, thus widening its applicability to pharmaceutical, cosmetic, and food industry. However, its vesicular structure is readily transferred to micelle in the presence of amphiphilic additives with low packing parameters. Therefore, it is critical to developing a technique to overcome this drawback. This study introduces a microfluidic approach to physically immobilize liposome in microgel particles. For this, we generate a uniform liposome-in-oil-in-water emulsion in a capillary-based microfluidic device. Basically, we observe how the flows in micro-channels affect generation of embryo emulsion drops. Then, the uniform emulsion is solidified by using photo-polymerization. Finally, we characterize the particle morphology, membrane fluidity, and mesh property, encapsulation efficiency and releasing.

Micellization and Single-Particle Encapsulation with Dimethylammoniopropyl Sulfobetaines

PubMed Central

2017-01-01

Sulfobetaines (SBs) are a class of zwitterionic surfactants with a reputation for enhancing colloidal stability at high salt concentrations. Here, we present a systematic study on the self-assembly of SB amphiphiles (sultaines or hydroxysultaines) in aqueous solutions, as a function of chain length and composition, ionic strength, and in the presence of alkanethiol-coated Au nanoparticles (GNPs). The diameters of the micelles assembled from SB and amidosulfobetaine (ASB) generally increase monotonically with chain length, although ASB micelles are smaller relative to alkyl SB micelles with similarly sized tailgroups, and oleyl sulfobetaine (OSB) micelles are slightly larger. SB amphiphiles can stabilize alkanethiol-coated GNPs in physiologically relevant buffers at concentrations well below their CMC, with size increases corresponding to single-particle encapsulation. SB-encapsulated GNPs were prepared by three different methods with SB:GNP weight ratios of 10:1, followed by dispersion in water or 1 M NaCl. The low hydrodynamic size of the SB micelles and SB-coated NPs is within the range needed for efficient renal clearance. PMID:28474008

Micellization and Single-Particle Encapsulation with Dimethylammoniopropyl Sulfobetaines.

PubMed

Wang, Jianxin; Morales-Collazo, Oscar; Wei, Alexander

2017-04-30

Sulfobetaines (SBs) are a class of zwitterionic surfactants with a reputation for enhancing colloidal stability at high salt concentrations. Here, we present a systematic study on the self-assembly of SB amphiphiles (sultaines or hydroxysultaines) in aqueous solutions, as a function of chain length and composition, ionic strength, and in the presence of alkanethiol-coated Au nanoparticles (GNPs). The diameters of the micelles assembled from SB and amidosulfobetaine (ASB) generally increase monotonically with chain length, although ASB micelles are smaller relative to alkyl SB micelles with similarly sized tailgroups, and oleyl sulfobetaine (OSB) micelles are slightly larger. SB amphiphiles can stabilize alkanethiol-coated GNPs in physiologically relevant buffers at concentrations well below their CMC, with size increases corresponding to single-particle encapsulation. SB-encapsulated GNPs were prepared by three different methods with SB:GNP weight ratios of 10:1, followed by dispersion in water or 1 M NaCl. The low hydrodynamic size of the SB micelles and SB-coated NPs is within the range needed for efficient renal clearance.

Elaboration of microparticles of carotenoids from natural and synthetic sources for applications in food.

PubMed

Rutz, Josiane K; Borges, Caroline D; Zambiazi, Rui C; da Rosa, Cleonice G; da Silva, Médelin M

2016-07-01

Carotenoids are susceptible to isomerization and oxidation upon exposure to oxygen, light and heat, which can result in loss of color, antioxidant activity, and vitamin activity. Microencapsulation helps retain carotenoid stability and promotes their release under specific conditions. Thus, the aim of the study was to encapsulate palm oil and β-carotene with chitosan/sodium tripolyphosphate or chitosan/carboxymethylcellulose and to assess the performance of these microparticles in food systems by analyzing their release profile under simulated gastric and intestinal conditions. Encapsulation efficiency was greater than 95%, and the yield of microparticles coated with chitosan/sodium tripolyphosphate was approximately 55%, while that of microparticles coated with chitosan/carboxymethylcellulose was 87%. Particles encapsulated with chitosan/carboxymethylcellulose exhibited ideal release behavior in water and gastric fluid, but showed low release in the intestinal fluid. However, when applied to food systems these particles showed enhanced carotenoid release but showed low release of carotenoids upon storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Control over Silica Particle Growth and Particle–Biomolecule Interactions Facilitates Silica Encapsulation of Mammalian Cells with Thickness Control

DOE PAGES

Johnston, Robert K.; Harper, Jason C.; Tartis, Michaelann S.

2017-07-13

Over the past 20 years, many strategies utilizing sol–gel chemistry to integrate biological cells into silica-based materials have been reported. One such strategy, Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition, shows promise as an efficient encapsulation technique due to the ability to vary the silica encapsulation morphology obtained by this process through variation of SG-CViL reaction conditions. In this report, we develop SG-CViL as a tunable, multi-purpose silica encapsulation strategy by investigating the mechanisms governing both silica particle generation and subsequent interaction with phospholipid assemblies (liposomes and living cells). Using Dynamic Light Scattering (DLS) measurements, linear and exponential silica particlemore » growth dynamics were observed which were dependent on deposition buffer ion constituents and ion concentration. Silica particle growth followed a cluster–cluster growth mechanism at acidic pH, and a monomer-cluster growth mechanism at neutral to basic pH. Increasing silica sol aging temperature resulted in higher rates of particle growth and larger particles. DLS measurements employing PEG-coated liposomes and cationic liposomes, serving as model phospholipid assemblies, revealed that electrostatic interactions promote more stable liposome–silica interactions than hydrogen bonding and facilitate silica coating on suspension cells. However, continued silica reactivity leads to aggregation of silica-coated suspension cells, revealing the need for cell isolation to tune deposited silica thickness. As a result, utilizing these mechanistic study insights, silica was deposited onto adherent HeLa cells under biocompatible conditions with micrometer-scale control over silica thickness, minimal cell manipulation steps, and retained cell viability over several days.« less

Control over Silica Particle Growth and Particle–Biomolecule Interactions Facilitates Silica Encapsulation of Mammalian Cells with Thickness Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Robert K.; Harper, Jason C.; Tartis, Michaelann S.

Over the past 20 years, many strategies utilizing sol–gel chemistry to integrate biological cells into silica-based materials have been reported. One such strategy, Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition, shows promise as an efficient encapsulation technique due to the ability to vary the silica encapsulation morphology obtained by this process through variation of SG-CViL reaction conditions. In this report, we develop SG-CViL as a tunable, multi-purpose silica encapsulation strategy by investigating the mechanisms governing both silica particle generation and subsequent interaction with phospholipid assemblies (liposomes and living cells). Using Dynamic Light Scattering (DLS) measurements, linear and exponential silica particlemore » growth dynamics were observed which were dependent on deposition buffer ion constituents and ion concentration. Silica particle growth followed a cluster–cluster growth mechanism at acidic pH, and a monomer-cluster growth mechanism at neutral to basic pH. Increasing silica sol aging temperature resulted in higher rates of particle growth and larger particles. DLS measurements employing PEG-coated liposomes and cationic liposomes, serving as model phospholipid assemblies, revealed that electrostatic interactions promote more stable liposome–silica interactions than hydrogen bonding and facilitate silica coating on suspension cells. However, continued silica reactivity leads to aggregation of silica-coated suspension cells, revealing the need for cell isolation to tune deposited silica thickness. As a result, utilizing these mechanistic study insights, silica was deposited onto adherent HeLa cells under biocompatible conditions with micrometer-scale control over silica thickness, minimal cell manipulation steps, and retained cell viability over several days.« less

Zinc phthalocyanine-loaded PLGA biodegradable nanoparticles for photodynamic therapy in tumor-bearing mice.

PubMed

Fadel, Maha; Kassab, Kawser; Fadeel, Doa Abdel

2010-03-01

Nanoparticles formulated from the biodegradable copolymer poly(lactic-coglycolic acid) (PLGA) were investigated as a drug delivery system to enhance tissue uptake, permeation, and targeting of zinc(II) phthalocyanine (ZnPc) for photodynamic therapy. Three ZnPc nanoparticle formulations were prepared using a solvent emulsion evaporation method and the influence of sonication time on nanoparticle shape, encapsulation and size distribution, in vitro release, and in vivo photodynamic efficiency in tumor-bearing mice were studied. Sonication time did not affect the process yield or encapsulation efficiency, but did affect significantly the particle size. Sonication for 20 min reduced the mean particle size to 374.3 nm and the in vitro release studies demonstrated a controlled release profile of ZnPc. Tumor-bearing mice injected with ZnPc nanoparticles exhibited significantly smaller mean tumor volume, increased tumor growth delay and longer survival compared with the control group and the group injected with free ZnPc during the time course of the experiment. Histopathological examination of tumor from animals treated with PLGA ZnPc showed regression of tumor cells, in contrast to those obtained from animals treated with free ZnPc. The results indicate that ZnPc encapsulated in PLGA nanoparticles is a successful delivery system for improving photodynamic activity in the target tissue.

New Method to Prepare Mitomycin C Loaded PLA-Nanoparticles with High Drug Entrapment Efficiency

NASA Astrophysics Data System (ADS)

Hou, Zhenqing; Wei, Heng; Wang, Qian; Sun, Qian; Zhou, Chunxiao; Zhan, Chuanming; Tang, Xiaolong; Zhang, Qiqing

2009-07-01

The classical utilized double emulsion solvent diffusion technique for encapsulating water soluble Mitomycin C (MMC) in PLA nanoparticles suffers from low encapsulation efficiency because of the drug rapid partitioning to the external aqueous phase. In this paper, MMC loaded PLA nanoparticles were prepared by a new single emulsion solvent evaporation method, in which soybean phosphatidylcholine (SPC) was employed to improve the liposolubility of MMC by formation of MMC-SPC complex. Four main influential factors based on the results of a single-factor test, namely, PLA molecular weight, ratio of PLA to SPC (wt/wt) and MMC to SPC (wt/wt), volume ratio of oil phase to water phase, were evaluated using an orthogonal design with respect to drug entrapment efficiency. The drug release study was performed in pH 7.2 PBS at 37 °C with drug analysis using UV/vis spectrometer at 365 nm. MMC-PLA particles prepared by classical method were used as comparison. The formulated MMC-SPC-PLA nanoparticles under optimized condition are found to be relatively uniform in size (594 nm) with up to 94.8% of drug entrapment efficiency compared to 6.44 μm of PLA-MMC microparticles with 34.5% of drug entrapment efficiency. The release of MMC shows biphasic with an initial burst effect, followed by a cumulated drug release over 30 days is 50.17% for PLA-MMC-SPC nanoparticles, and 74.1% for PLA-MMC particles. The IR analysis of MMC-SPC complex shows that their high liposolubility may be attributed to some weak physical interaction between MMC and SPC during the formation of the complex. It is concluded that the new method is advantageous in terms of smaller size, lower size distribution, higher encapsulation yield, and longer sustained drug release in comparison to classical method.

Induced Förster resonance energy transfer by encapsulation of DNA-scaffold based probes inside a plant virus based protein cage

NASA Astrophysics Data System (ADS)

de Ruiter, Mark V.; Overeem, Nico J.; Singhai, Gaurav; Cornelissen, Jeroen J. L. M.

2018-05-01

Insight into the assembly and disassembly of viruses can play a crucial role in developing cures for viral diseases. Specialized fluorescent probes can benefit the study of interactions within viruses, especially during cell studies. In this work, we developed a strategy based on Förster resonance energy transfer (FRET) to study the assembly of viruses without labeling the exterior of viruses. Instead, we exploit their encapsulation of nucleic cargo, using three different fluorescent ATTO dyes linked to single-stranded DNA oligomers, which are hybridised to a longer DNA strand. FRET is induced upon assembly of the cowpea chlorotic mottle virus, which forms monodisperse icosahedral particles of about 22 nm, thereby increasing the FRET efficiency by a factor of 8. Additionally, encapsulation of the dyes in virus-like particles induces a two-step FRET. When the formed constructs are disassembled, this FRET signal is fully reduced to the value before encapsulation. This reversible behavior makes the system a good probe for studying viral assembly and disassembly. It, furthermore, shows that multi-component supramolecular materials are stabilized in the confinement of a protein cage.

Encapsulating anthocyanins from Hibiscus sabdariffa L. calyces by ionic gelation: Pigment stability during storage of microparticles.

PubMed

de Moura, Sílvia C S R; Berling, Carolina L; Germer, Sílvia P M; Alvim, Izabela D; Hubinger, Míriam D

2018-02-15

Hibiscus extract (HE) has a strong antioxidant activity and high anthocyanin content; it can be used as a natural pigment, also adding potential health benefits. The objective of this work was the microencapsulation of HE anthocyanin by ionic gelation (IG) using two techniques: dripping-extrusion and atomization, both by means of a double emulsion (HE/rapseed oil/pectin) and a cross-linked solution (CaCl 2 ). Particles (77-83% moisture content) were conditioned in acidified solution at 5, 15 and 25°C, absence of light, and evaluated for anthocyanins and color for 50-days. The median diameter (D 50 ) of the particles ranged from 78 to 1100μm and encapsulation efficiency ranged from 67.9 to 93.9%. The encapsulation caused higher temperature stability compared with the free extract. The half-life (t 1/2 ) values of the particles ranged from 7 (25°C) to 180days (5°C) for anthocyanins and from 25 (25°C) to 462days (5°C) for Chroma value. The IG increased the stability of HE anthocyanin. Both the dripping-extrusion and the atomization have shown to be feasible techniques. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phosphatidylcholine nanovesicles coated with chitosan or chondroitin sulfate as novel devices for bacteriocin delivery

NASA Astrophysics Data System (ADS)

da Silva, Indjara Mallmann; Boelter, Juliana Ferreira; da Silveira, Nádya Pesce; Brandelli, Adriano

2014-07-01

There is increased interest on the use of natural antimicrobial peptides in biomedicine and food preservation technologies. In this study, the antimicrobial activity of nisin encapsulated into nanovesicles containing polyanionic polysaccharides was investigated. Nisin was encapsulated in phosphatidylcholine (PC) liposomes containing chitosan or chondroitin sulfate by the thin-film hydration method and tested for antimicrobial activity against Listeria spp. The mean particle size of PC liposomes was 145 nm and varied to 210 and 134 nm with the incorporation of chitosan and chondroitin sulfate, respectively. Nisin-containing nanovesicles with and without incorporation of polysaccharides had a zeta potential values around -20 mV, showing mostly spherical structures when observed by transmission electron microscopy. Encapsulated nisin had similar efficiency as free nisin in inhibiting Listeria spp. isolated from bovine carcass, and greater efficiency in inhibiting Listeria monocytogenes. The formulation containing chitosan was more stable and more efficient in inhibiting L. monocytogenes when compared to the other nanovesicles tested. After 24 h, the viable cell counts were 2 log lower as compared with the other treatments and 7 log comparing to controls.

Nanoparticles Based on Chitosan as Carriers for the Combined Herbicides Imazapic and Imazapyr

PubMed Central

Maruyama, Cintia Rodrigues; Guilger, Mariana; Pascoli, Mônica; Bileshy-José, Natalia; Abhilash, P.C.; Fraceto, Leonardo Fernandes; de Lima, Renata

2016-01-01

The use of lower concentrations and fewer applications of herbicides is one of the prime objectives of the sustainable agriculture as it decreases the toxicity to non-targeted organisms and the risk of wider environmental contamination. In the present work, nanoparticles were developed for encapsulation of the herbicides imazapic and imazapyr. Alginate/chitosan and chitosan/tripolyphosphate nanoparticles were manufactured, and their physicochemical stability was evaluated. Determinations were made of the encapsulation efficiency and release kinetics, and the toxicity of the nanoparticles was evaluated using cytotoxicity and genotoxicity assays. The effects of herbicides and herbicide-loaded nanoparticles on soil microorganisms were studied in detail using real-time polymerase chain reactions. The nanoparticles showed an average size of 400 nm and remained stable during 30 days of storage at ambient temperature. Satisfactory encapsulation efficiencies of between 50 and 70% were achieved for both types of particles. Cytotoxicity assays showed that the encapsulated herbicides were less toxic, compared to the free compounds, and genotoxicity was decreased. Analyses of soil microbiota revealed changes in the bacteria of the soils exposed to the different treatments. Our study proves that encapsulation of the herbicides improved their mode of action and reduced their toxicity, indicating their suitability for use in future practical applications. PMID:26813942

Preparation and characterization of microparticles of β-cyclodextrin/glutathione and chitosan/glutathione obtained by spray-drying.

PubMed

Webber, Vanessa; de Siqueira Ferreira, Daniel; Barreto, Pedro Luis Manique; Weiss-Angeli, Valeria; Vanderlinde, Regina

2018-03-01

Reduced glutathione (GSH) is an efficient antioxidant on limitation of browning, of the loss of aromas and off-flavor formation in white wines. The encapsulation of GSH in a polymer system to be added in white wines may prolong its antioxidant action. The aim of this work was to prepare and characterize spray-dried microparticles using β-cyclodextrin (β-CD) or chitosan as polymers for encapsulation of GSH for its addition to wine to prevent oxidation. The microparticles obtained after the drying process were characterized regarding morphology, chemical interaction between GSH and polymers, thermal stability, microstructure, encapsulation efficiency and in vitro GSH release. SEM showed spherical microparticles, with wrinkled surfaces for β-CD/GSH and smooth surfaces for chitosan/GSH. A wide distribution of particle size was observed. In general, β-CD/GSH showed an average diameter smaller than the chitosan/GSH microparticles. FT-IR showed a possible interaction between GSH and both polymers. DSC and DRX showed that encapsulation process produced a marked decrease in GSH crystallinity. The encapsulation efficiency was 25.0% for chitosan/GSH and 62.4% for β-CD/GSH microparticles. The GSH release profiles from microparticles showed that β-CD can control the release behaviors of GSH better than chitosan in a model wine. Cumulative release data were fitted to an empirical equation to compute diffusional exponent (n), which indicates a trend the non-Fickian release of GSH. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polymeric nano-encapsulation of 5-fluorouracil enhances anti-cancer activity and ameliorates side effects in solid Ehrlich Carcinoma-bearing mice.

PubMed

Haggag, Yusuf A; Osman, Mohamed A; El-Gizawy, Sanaa A; Goda, Ahmed E; Shamloula, Maha M; Faheem, Ahmed M; McCarron, Paul A

2018-05-29

Biodegradable PLGA nanoparticles, loaded with 5-fluorouracil (5FU), were prepared using a double emulsion method and characterised in terms of mean diameter, zeta potential, entrapment efficiency and in vitro release. Poly (vinyl alcohol) was used to modify both internal and external aqueous phases and shown have a significant effect on nanoparticulate size, encapsulation efficiency and the initial burst release. Addition of poly (ethylene glycol) to the particle matrix, as part of the polymeric backbone, improved significantly the encapsulation efficiency. 5FU-loaded NPs were spherical in shape and negatively charged with a size range of 185-350 nm. Biological evaluation was performed in vivo using a solid Ehrlich carcinoma (SEC) murine model. An optimised 5FU-loaded formulation containing PEG as part of a block copolymer induced a pronounced reduction in tumour volume and tumour weight, together with an improved percentage tumour growth inhibition. Drug-loaded nanoparticles showed no significant toxicity or associated changes on liver and kidney function in tested animals, whereas increased alanine aminotransferase, aspartate aminotransferase and serum creatinine were observed in animals treated with free 5FU. Histopathological examination demonstrated enhanced cytotoxic action of 5FU-loaded nanoparticles when compared to the free drug. Based on these findings, it was concluded that nano-encapsulation of 5FU using PEGylated PLGA improved encapsulation and sustained in vitro release. This leads to increased anti-tumour efficacy against SEC, with a reduction in adverse effects. Published by Elsevier Masson SAS.

Preparation and characterization of protein-loaded poly(epsilon-caprolactone) microparticles for oral vaccine delivery.

PubMed

Benoit, M A; Baras, B; Gillard, J

1999-07-05

This paper describes the conditions of preparation of poly(epsilon-caprolactone) (PCL) microparticles with a mean size between 5 and 10 microm, obtained by a double emulsion-solvent evaporation technique, suitable for oral vaccine delivery. Bovine serum albumin (BSA) was used as water-soluble model antigen for encapsulation. Different parameters influencing the microparticle size, the BSA loading and entrapment efficiency were investigated. Spherical, smooth and homogeneously distributed microparticles were produced with a BSA loading and entrapment efficiency reaching, respectively, 5% (w/w) and 30%. Polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (IEF) analyses of BSA released from these particles confirmed that the entrapped protein seemed to remain unaltered by the protein encapsulation process. Copyright.

Effect of liquid-to-solid lipid ratio on characterizations of flurbiprofen-loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) for transdermal administration.

PubMed

Song, Aihua; Zhang, Xiaoshu; Li, Yanting; Mao, Xinjuan; Han, Fei

2016-08-01

The aim of this study is to evaluate the effect of liquid-to-solid lipid ratio on properties of flurbiprofen-loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), and to clarify the superiority of NLCs over SLNs for transdermal administration. Particle size, zeta potential, drug encapsulation efficiency, in vitro occlusion factor, differential scanning calorimetry, X-ray diffractometry, in vitro percutaneous permeation profile, and stability of SLNs and NLCs were compared. Particle size, zeta potential, drug encapsulation efficiency, in vitro occlusion factor, and in vitro percutaneous permeation amount of the developed NLCs were all <200 nm, < -20 mV, >78%, >35, and >240 μg/cm(2), respectively, however, for SLNs were 280 nm, -29.11 mV, 63.2%, 32.54, and 225.9 μg/cm(2), respectively. After 3 months storage at 4 °C and 25 °C, almost no significant differences between the evaluated parameters of NLCs were observed. However, for SLNs, particle size was increased to higher than 300 nm (4 °C and 25 °C), drug encapsulation efficiency was decreased to 51.2 (25 °C), in vitro occlusion factor was also decreased to lower than 25 (4 °C and 25 °C), and the cumulative amount was decreased to 148.9 μg/cm(2) (25 °C) and 184.4 μg/cm(2) (4 °C), respectively. And DSC and XRD studies indicated that not only the crystalline peaks of the encapsulated flurbiprofen disappeared but also obvious difference between samples and bulk Compritol® ATO 888 was seen. It could be concluded that liquid-to-solid lipid ratio has significant impact on the properties of SLNs and NLCs, and NLCs showed better stability than SLNs. Therefore, NLCs might be a better option than SLNs for transdermal administration.

Preparation and characterization of bee venom-loaded PLGA particles for sustained release.

PubMed

Park, Min-Ho; Jun, Hye-Suk; Jeon, Jong-Woon; Park, Jin-Kyu; Lee, Bong-Joo; Suh, Guk-Hyun; Park, Jeong-Sook; Cho, Cheong-Weon

2016-12-14

Bee venom-loaded poly(lactic-co-glycolic acid) (PLGA) particles were prepared by double emulsion-solvent evaporation, and characterized for a sustained-release system. Factors such as the type of organic solvent, the amount of bee venom and PLGA, the type of PLGA, the type of polyvinyl alcohol, and the emulsification method were considered. Physicochemical properties, including the encapsulation efficiency, drug loading, particle size, zeta-potential and surface morphology were examined by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The size of the bee venom-loaded PLGA particles was 500 nm (measured using sonication). Zeta-potentials of the bee venom-loaded PLGA particles were negative owing to the PLGA. FT-IR results demonstrated that the bee venom was completely encapsulated in the PLGA particles, indicated by the disappearance of the amine and amide peaks. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the bee venom in the bee venom-loaded PLGA particles was intact. In vitro release of the bee venom from the bee venom-loaded PLGA particles showed a sustained-release profile over 1 month. Bee venom-loaded PLGA particles can help improve patients' quality of life by reducing the number of injections required.

Preparation of siRNA encapsulated nanoliposomes suitable for siRNA delivery by simply discontinuous mixing.

PubMed

Mokhtarieh, Amir Abbas; Lee, Jieun; Kim, Semi; Lee, Myung Kyu

2018-06-01

Previously a scalable and extrusion-free method has been developed for efficient liposomal encapsulation of DNA by twice stepwise mixing of lipids in ethanol and DNA solution using T-shape mixing chamber. In this study, we prepared nanoliposomes encapsulating siRNA by simply discontinuous mixing of lipids in ethanol/ether/water mixture and acidic siRNA solution without use of special equipment. The simple mixing siRNA/liposomal particles (siRNA/SMLs) prepared using ethanol/ether/water (3:1:1) mixture showed 120.4 ± 20.2 nm particle size, 0.174 ± 0.033 polydispersity and 86.5 ± 2.76% siRNA encapsulation rate. In addition, the SMLs almost completely protected the encapsulated siRNA from RNase A digestion. Coupling of anti-human epidermal growth factor receptor (EGFR) Fab' to siRNA/SMLs enhanced EGFR-specific cell penetration of SMLs and induced siRNA dependent gene silencing. Unexpectedly, the Cy5.5-labeled Fab' showed almost no in vivo targeting to the xenografted A549 tumors in SCID-NOD mice. However, multiple injection of the unmodified siRNA/SMLs accumulated in the tumors and induced siRNA-dependent in vivo gene silencing. These results demonstrate that the siRNA/SMLs can be used as a siRNA delivery tool for gene therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of barrier properties of zein colloidal particles and oil-in-water emulsions on oxidative stability of encapsulated bioactive compounds

USDA-ARS?s Scientific Manuscript database

Oxidation of encapsulated bioactive compounds is a key challenge that limits shelf-life of bioactive containing products. The objectives of this study were to compare differences between the oxidative barrier properties of biopolymer particle based encapsulation system (zein colloidal particles) and...

Enhanced drug encapsulation and extended release profiles of calcium-alginate nanoparticles by using tannic acid as a bridging cross-linking agent.

PubMed

Abulateefeh, Samer R; Taha, Mutasem O

2015-01-01

Calcium alginate nanoparticles (NPs) suffer from sub-optimal stability in bio-relevant media leading to low drug encapsulation efficiency and uncontrolled release profiles. To sort out these drawbacks, a novel approach is proposed herein based on introducing tannic acid into these NPs to act as a bridging cross-linking aid agent. Calcium-alginate NPs were prepared by the ionotropic gelation method and loaded with diltiazem hydrochloride as a model drug. These NPs were characterized in terms of particle size, zeta potential, and morphology, and results were explained in accordance with Fourier-transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The incorporation of tannic acid led to more than four folds increase in drug encapsulation efficiency (i.e. from 15.3% to 69.5%) and reduced burst drug release from 44% to around 10% within the first 30 min. These findings suggest the possibility of improving the properties of Ca-alginate NPs by incorporating cross-linking aid agents under mild conditions.

The preparation and the sustained release of titanium dioxide hollow particles encapsulating L-ascorbic acid

NASA Astrophysics Data System (ADS)

Tominaga, Yoko; Kadota, Kazunori; Shimosaka, Atsuko; Yoshida, Mikio; Oshima, Kotaro; Shirakawa, Yoshiyuki

2018-05-01

The preparation of the titanium dioxide hollow particles encapsulating L-ascorbic acid via sol-gel process using inkjet nozzle has been performed, and the sustained release and the effect protecting against degradation of L-ascorbic acid in the particles were investigated. The morphology of titanium dioxide particles was evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The sustained release and the effect protecting against degradation of L-ascorbic acid were estimated by dialysis bag method in phosphate buffer saline (PBS) (pH = 7.4) as release media. The prepared titanium dioxide particles exhibited spherical porous structures. The particle size distribution of the titanium dioxide particles was uniform. The hollow titanium dioxide particles encapsulating L-ascorbic acid showed the sustained release. It was also found that the degradation of L-ascorbic acid could be inhibited by encapsulating L-ascorbic acid in the titanium dioxide hollow particles.

Formulation and evaluation of lidocaine base ethosomes for transdermal delivery.

PubMed

Zhu, Xiaoliang; Li, Fuli; Peng, Xuebiao; Zeng, Kang

2013-08-01

Although transdermal preparations of local anesthetics have been used to reduce pain caused by skin surgery, these preparations cannot effectively penetrate through the epidermis because of the barrier formed by the stratum corneum and the thick epidermis. Ethosomes can effectively transport drugs across the skin because of their thermodynamic stability, small size, high encapsulation efficiency, and percutaneous penetration. We evaluated lidocaine base ethosomes by measuring their loading efficiency, encapsulation efficiency, thermodynamic stability, and percutaneous penetration capability in vitro, and their effectiveness and cutaneous irritation in vivo. Lidocaine base ethosomes were prepared using the injection-sonication-filter method. Size, loading efficiency, encapsulation efficiency, and stability were evaluated using a Zetasizer and high performance liquid chromatography. Formulation was determined by measuring the maximum encapsulation efficiency in the orthogonal test. Percutaneous penetration efficiency in vitro was analyzed using a Franz-type diffusion cell experiment. In vivo effectiveness was analyzed using the pinprick test. Cutaneous irritancy tests were performed on white guinea pigs, followed by histopathologic analysis. The results were compared with lidocaine liposomes as well as lidocaine delivered in a hydroethanolic solution. Lidocaine base ethosomes composed of 5% (w/w) egg phosphatidyl choline, 35% (w/w) ethanol, 0.2% (w/w) cholesterol, 5% (w/w) lidocaine base, and ultrapure water had a mean maximum encapsulation of 51% ± 4%, a mean particle size of 31 ± 3 nm, and a mean loading efficiency of 95.0% ± 0.1%. The encapsulation efficiency of lidocaine base ethosomes remained stable for 60 days at 25°C ± 1°C (95% confidence interval [CI], -1.12% to 1.34%; P = 0.833). The transdermal flux of lidocaine base differed significantly for the 3 preparations (F = 120, P < 0.001), being significantly greater from ethosomes than from liposomes (95% corrected CI, 1129-1818 µg/(cm(2)·h); P < 0.001), and from hydroethanolic solution (95% corrected CI, 1468-2157 µg/(cm(2)·h); P < 0.001). Lidocaine base ethosomes had a shorter onset time and longer duration in vivo than did lidocaine base liposomes or lidocaine delivered in a hydroethanolic solution. Lidocaine base ethosomes showed no evidence of dermal irritation in guinea pigs. Ethosomes are potential carriers of local anesthetics across the skin and may have applicability for other percutaneous drugs that require rapid onset.

Encapsulation and controlled release of retinol from silicone particles for topical delivery.

PubMed

Shields, C Wyatt; White, John P; Osta, Erica G; Patel, Jerishma; Rajkumar, Shashank; Kirby, Nickolas; Therrien, Jean-Philippe; Zauscher, Stefan

2018-05-28

Retinol, a derivative of vitamin A, is a ubiquitous compound used to treat acne, reduce wrinkles and protect against conditions like psoriasis and ichthyosis. While retinol is used as the primary active ingredient (AI) in many skin care formulations, its efficacy is often limited by an extreme sensitivity to degrade and toxicity at high concentrations. While microencapsulation is an appealing method to help overcome these issues, few microencapsulation strategies have made a major translational impact due to challenges with complexity, cost, limited protection of the AI and poor control of the release of the AI. We have developed a class of silicone particles that addresses these challenges for the encapsulation, protection and controlled release of retinol and other hydrophobic compounds. The particles are prepared by the sol-gel polymerization of silane monomers, which enables their rapid and facile synthesis at scale while maintaining a narrow size distribution (i.e., CV < 20%). We show that our particles can: (i) encapsulate retinol with high efficiency (>85%), (ii) protect retinol from degradation (yielding a half-life 9× greater than unencapsulated retinol) and (iii) slowly release retinol over several hours (at rates from 0.14 to 0.67 μg cm -2  s -1/2 ). To demonstrate that the controlled release of retinol from the particles can reduce irritation, we performed a double blind study on human subjects and found that formulations containing our particles were 12-23% less irritating than identical formulations containing Microsponge® particles (an industry standard by Amcol, Inc.). To show that the silicone particles can elicit a favorable biological response, similar to the Microsponge® particles, we applied both formulations to reconstructed human epidermal tissues and found an upregulation of keratin 19 (K19) and a downregulation of K10, indicating that the reduced irritation observed in the human study was not caused by reduced activity. We also found a decrease in the production of interleukin-1α (IL-1α) compared to formulations containing the Microsponge particles, suggesting lower irritation levels and supporting the findings from the human study. Finally, we show that the silicone particles can encapsulate other AIs, including betamethasone, N, N-diethyl-meta-toluamide (DEET), homosalate and ingenol mebutate, establishing these particles as a true platform technology. Copyright © 2018. Published by Elsevier B.V.

Simultant encapsulation of vitamin C and beta-carotene in sesame (Sesamum indicum l.) liposomes

NASA Astrophysics Data System (ADS)

Hudiyanti, D.; Fawrin, H.; Siahaan, P.

2018-04-01

In this study sesame liposomes were used to encapsulate both vitamin C and beta-carotene simultaneously. Liposomes were prepared with addition of cholesterol. The encapsulation efficiency (EE) of sesame liposomes for vitamin C in the present of beta-carotene was 77%. The addition of cholesterol increased the encapsulation efficiency. The highest encapsulation efficiency was 89% obtained in liposomes with 10% and 20% cholesterol. Contrary to that, the highest beta-carotene encapsulation efficiency of 78%, was found in the sesame liposomes prepared without the added cholesterol. Results showed that sesame liposomes can be used to encapsulate beta-carotene and vitamin C simultaneously. When beta-carotene and vitamin C were encapsulated concurrently, cholesterol intensified the efficiency of vitamin C encapsulation on the contrary it diminished the efficiency of beta-carotene encapsulation.

Development and characterization of polymer-oil nanostructured carrier (PONC) for controlled delivery of all-trans retinoic acid (ATRA)

NASA Astrophysics Data System (ADS)

Narvekar, Mayuri M.

The commonly used PLGA-based delivery systems are often limited by their inadequate drug loading and release properties. This study reports the integration of oil into PLGA to form the prototype of a hybrid drug carrier PONC. Our primary goal is to confer the key strength of lipid-based drug carriers, i.e. efficient encapsulation of lipophilic compounds, to a PLGA system without taking away its various useful qualities. The PONC were formulated by emulsification solvent evaporation technique, which were then characterized for particle size, encapsulation efficiency, drug release and anticancer efficacy. The ATRA loaded PONC showed excellent encapsulation efficiency and release kinetics. Even after surface functionalization with PEG , controlled drug release kinetics was maintained, with 88.5% of the encapsulated ATRA released from the PEG-PONC in a uniform manner over 120 hours. It also showed favorable physicochemical properties and serum stability. PEG-PONC has demonstrated substantially superior activity over the free ATRA in ovarian cancer cells that are non-responsive to the standard chemotherapy. The newly developed PEG-PONC significantly reduced the IC50 values (p<0.05) in the chemoresistant cells in both MTT and colony formation assays. Hence, this new ATRA-nanoformulation may offer promising means for the delivery of lipophilic compounds like all-trans retinoic acid to treat highly resistant ovarian cancer.

Fabrication of composite poly(d,l-lactide)/montmorillonite nanoparticles for controlled delivery of acetaminophen by solvent-displacement method using glass capillary microfluidics.

PubMed

Othman, Rahimah; Vladisavljević, Goran T; Thomas, Noreen L; Nagy, Zoltan K

2016-05-01

Paracetamol (PCM)-loaded composite nanoparticles (NPs) composed of a biodegradable poly(d,l-lactide) (PLA) polymer matrix filled with organically modified montmorillonite (MMT) nanoparticles were fabricated by antisolvent nanoprecipitation in a microfluidic co-flow glass capillary device. The incorporation of MMT in the polymer improved both the drug encapsulation efficiency and the drug loading, and extended the rate of drug release in simulated intestinal fluid (pH 7.4). The particle size increased on increasing both the drug loading and the concentration of MMT in the polymer matrix, and decreased on increasing the aqueous to organic flow rate ratio. The drug encapsulation efficiency in the NPs was higher at higher aqueous to organic flow rate ratio due to faster formation of the NPs. The PCM-loaded PLA NPs containing 2 wt% MMT in PLA prepared at an aqueous to organic flow rate ratio of 10 with an orifice size of 200 μm exhibited a spherical shape with a mean size of 296 nm, a drug encapsulation efficiency of 38.5% and a drug loading of 5.4%. The encapsulation of MMT and PCM in the NPs was confirmed by transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and attenuated total reflection-Fourier transform infrared spectroscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative studies on exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles prepared by a novel ultra-fine particle processing system and spray drying.

PubMed

Zhu, Chune; Huang, Ying; Zhang, Xiaoying; Mei, Liling; Pan, Xin; Li, Ge; Wu, Chuanbin

2015-08-01

The purpose of this study was to compare the properties of exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles (Ex-PLGA-MPs) prepared by a novel ultra-fine particle processing system (UPPS) and spray drying. UPPS is a proprietary technology developed by our group based on the disk rotation principle. Characteristics of the MPs including morphology, particle size distribution, drug content, encapsulation efficiency and in vitro release were comparatively studied. Cytotoxicity of the MPs was examined on A549 cells and the pharmacodynamics was investigated in vivo in type 2 diabetes Sprague-Dawley (SD) rats. Ex-PLGA-MPs prepared by UPPS showed larger particle size, denser surface, greater encapsulation efficiency, less initial burst release, and stable sustained release for more than one month in vitro as compared with the spray drying MPs. Meanwhile, the UPPS MPs effectively controlled the body growth rate and blood glucose in diabetes rats for at least three weeks after a single injection, while the spray drying MPs showed effective control period of about two weeks. UPPS technology was demonstrated to manufacture Ex-PLGA-MPs as a potential sustained release protein/polypeptide delivery system, which is an alternative method for the most commonly used spray drying. This comparative research provides a new guidance for microparticle preparation technology. Copyright © 2015 Elsevier B.V. All rights reserved.

Curcumin loaded pH-sensitive nanoparticles for the treatment of colon cancer.

PubMed

Prajakta, Dandekar; Ratnesh, Jain; Chandan, Kumar; Suresh, Subramanian; Grace, Samuel; Meera, Venkatesh; Vandana, Patravale

2009-10-01

The investigation was aimed at designing pH-sensitive, polymeric nanoparticles of curcumin, a natural anti-cancer agent, for the treatment of colon cancer. The objective was to enhance the bioavailability of curcumin, simultaneously reducing the required dose through selective targeting to colon. Eudragit S100 was chosen to aid targeting since the polymer dissolves at colonic pH to result in selective colonic release of the entrapped drug. Solvent emulsion-evaporation technique was employed to formulate the nanoparticles. Various process parameters were optimized and the optimized formulation was evaluated for particle size distribution and encapsulation efficiency before subjecting to freeze-drying. The freeze dried product was characterized for particle size, drug content, DSC studies, particle morphology. Anti-cancer potential of the formulation was demonstrated by MTT assay in HT-29 cell line. Nanometric, homogeneous, spherical particles were obtained with encapsulation efficiency of 72%. Freeze-dried nanoparticles exhibited a negative surface charge, drug content of > 99% and presence of drug in amorphous form which may result in possible enhanced absorption. MTT assay demonstrated almost double inhibition of the cancerous cells by nanoparticles, as compared to curcumin alone, at the concentrations tested. Enhanced action may be attributed to size influenced improved cellular uptake, and may result in reduction of overall dose requirement. Results indicate the potential for in vivo studies to establish the clinical application of the formulation.

Encapsulation of methotrexate loaded magnetic microcapsules for magnetic drug targeting and controlled drug release

NASA Astrophysics Data System (ADS)

Chakkarapani, Prabu; Subbiah, Latha; Palanisamy, Selvamani; Bibiana, Arputha; Ahrentorp, Fredrik; Jonasson, Christian; Johansson, Christer

2015-04-01

We report on the development and evaluation of methotrexate magnetic microcapsules (MMC) for targeted rheumatoid arthritis therapy. Methotrexate was loaded into CaCO3-PSS (poly (sodium 4-styrenesulfonate)) doped microparticles that were coated successively with poly (allylamine hydrochloride) and poly (sodium 4-styrenesulfonate) by layer-by-layer technique. Ferrofluid was incorporated between the polyelectrolyte layers. CaCO3-PSS core was etched by incubation with EDTA yielding spherical MMC. The MMC were evaluated for various physicochemical, pharmaceutical parameters and magnetic properties. Surface morphology, crystallinity, particle size, zeta potential, encapsulation efficiency, loading capacity, drug release pattern, release kinetics and AC susceptibility studies revealed spherical particles of ~3 μm size were obtained with a net zeta potential of +24.5 mV, 56% encapsulation and 18.6% drug loading capacity, 96% of cumulative drug release obeyed Hixson-Crowell model release kinetics. Drug excipient interaction, surface area, thermal and storage stability studies for the prepared MMC was also evaluated. The developed MMC offer a promising mode of targeted and sustained release drug delivery for rheumatoid arthritis therapy.

Near-Infrared-Induced Heating of Confined Water in Polymeric Particles for Efficient Payload Release

PubMed Central

2015-01-01

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution. PMID:24717072

Near-infrared-induced heating of confined water in polymeric particles for efficient payload release.

PubMed

Viger, Mathieu L; Sheng, Wangzhong; Doré, Kim; Alhasan, Ali H; Carling, Carl-Johan; Lux, Jacques; de Gracia Lux, Caroline; Grossman, Madeleine; Malinow, Roberto; Almutairi, Adah

2014-05-27

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution.

Development of a balloon-borne device for analysis of high-altitude ice and aerosol particulates: Ice Cryo Encapsulator by Balloon (ICE-Ball)

NASA Astrophysics Data System (ADS)

Boaggio, K.; Bandamede, M.; Bancroft, L.; Hurler, K.; Magee, N. B.

2016-12-01

We report on details of continuing instrument development and deployment of a novel balloon-borne device for capturing and characterizing atmospheric ice and aerosol particles, the Ice Cryo Encapsulator by Balloon (ICE-Ball). The device is designed to capture and preserve cirrus ice particles, maintaining them at cold equilibrium temperatures, so that high-altitude particles can recovered, transferred intact, and then imaged under SEM at an unprecedented resolution (approximately 3 nm maximum resolution). In addition to cirrus ice particles, high altitude aerosol particles are also captured, imaged, and analyzed for geometry, chemical composition, and activity as ice nucleating particles. Prototype versions of ICE-Ball have successfully captured and preserved high altitude ice particles and aerosols, then returned them for recovery and SEM imaging and analysis. New improvements include 1) ability to capture particles from multiple narrowly-defined altitudes on a single payload, 2) high quality measurements of coincident temperature, humidity, and high-resolution video at capture altitude, 3) ability to capture particles during both ascent and descent, 4) better characterization of particle collection volume and collection efficiency, and 5) improved isolation and characterization of capture-cell cryo environment. This presentation provides detailed capability specifications for anyone interested in using measurements, collaborating on continued instrument development, or including this instrument in ongoing or future field campaigns.

Magnetic properties and transmission electron microscopy studies of Ni nanoparticles encapsulated in carbon nanocages and carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

He Chunnian; Zhao Naiqin; Shi Chunsheng

2008-08-04

Three types of carbon nanomaterials, including bamboo-shaped carbon nanotubes with Ni encapsulated and hollow and Ni catalytic particles filled carbon nanocages, have been prepared by methane catalytic decomposition at a relatively low temperature. Transmission electron microscopy observations showed that fascinating fullerene-like Ni-C (graphitic) core-shell nanostructures predominated. Detailed examination of high-resolution transmission electron microscopy showed that the walls of bamboo-shaped carbon nanotubes with quasi-cone catalytic particles encapsulated consisted of oblique graphene planes with respect to the tube axis. The Ni particles encapsulated in the carbon nanocages were larger than that encapsulated in carbon nanotubes, but the diameters of the cores ofmore » hollow carbon nanocages were less than that of Ni particles encapsulated in carbon nanotubes, suggesting that the sizes of catalyst particles played an important role during carbon nanomaterial growth. The magnetic properties of the carbon nanomaterials were measured, which showed relatively large coercive force (H{sub c} = 138.4 O{sub e}) and good ferromagnetism (M{sub r}/M{sub s} = 0.325)« less

Biocompatible microemulsions for fabrication of glyceryl monostearate solid lipid nanoparticles (SLN) of tretinoin.

PubMed

Shah, Kumar A; Joshi, Medha D; Patravale, Vandana B

2009-08-01

The objective of the present investigation was to fabricate glyceryl monostearate SLN by employing a biocompatible microemulsion as a template. Biocompatible excipients such as Tween 20 (as a surfactant) and Transcutol P (a cosourfactant) (at different K(m) ratios) were selected for the fabrication of microemulsions. Pseudo-ternary phase diagrams were plotted to identify the area of the microemulsion existence. Glyceryl monostearate SLN were fabricated by dispersing the microemulsion (maintained at 65 degrees C) into cold water (maintained at 2-3 degrees C). The particle size of the SLN was determined by photon correlation spectroscopy. Tretinoin, a lipophilic anti-acne agent was incorporated into SLN as a model drug. The encapsulation efficiency of tretinoin in the SLN was determined by using Nanosep ultrafilteration device at different lipid loads viz. 1%, 1.5% and 2%. Glyceryl monostearate SLN fabricated from biocompatible microemulsion template exhibited average particle size of 175 nm and polydispersity index of 0.833. Tretinoin could be successfully incorporated into SLN and the encapsulation efficiency ranged from 37-48% at different lipid loads.

UV-screening chitosan nanocontainers: increasing the photostability of encapsulated materials and controlled release

NASA Astrophysics Data System (ADS)

Anumansirikul, Nattaporm; Wittayasuporn, Mayura; Klinubol, Patcharawalai; Tachaprutinun, A.; Wanichwecharungruang, Supason P.

2008-05-01

Methyl ether terminated poly(ethylene glycol)-4-methoxycinnamoylphthaloylchitosan (PCPLC), a UV absorptive polymer, and methyl ether terminated poly(ethylene glycol)-phthaloylchitosan (PPLC) were synthesized, characterized and self-assembled into stable water-dispersible spherical nanoparticles. The encapsulation of a model compound, 2-ethylhexyl-4-methoxycinnamate (EHMC), was carried out to give particles with 67% (w/w) EHMC loading. The E to Z photoisomerization of EHMC encapsulated inside both particles was monitored and compared to non-encapsulated EHMC. Minimal E to Z photoisomerization was observed when EHMC was encapsulated in PCPLC particles prepared from a polymer with a maximum degree of 4-methoxycinnamoyl substitution. The results indicated that the grafted UVB absorptive chromophore, 4-methoxycinnamoyl moieties, situated at the shell of PCPLC nanoparticles acted as a UV-filtering barrier, protecting the encapsulated EHMC from the UVB radiation, thus minimizing its photoisomerization. In vitro experiments revealed the pH-dependent controlled release of EHMC from PCPLC and PPLC particles. Ex vivo experiments, using a Franz diffusion cell with baby mouse skin, indicated that neither PPLC nor PCPLC particles could penetrate the skin into the receptor medium after a 24 h topical application. When applied on the baby mouse skin, both EHMC-encapsulated PPLC and EHMC-encapsulated PCPLC showed comparable controlled releases of the EHMC. The released EHMC could transdermally penetrate the baby mouse skin.

[Preparation and in vitro release characteristics of vincristine sulphate loaded poly (butylcyanoacrylate) nanoparticles].

PubMed

Tan, Rong; Liu, Ying; Feng, Nianping; Zhao, Jihui

2011-06-01

To prepare vincristine sulphate loaded poly (butylcyanoacrylate) nanoparticles (VCR-PBCA-NPs) and to investigate the in vitro release charactersitics. VCR-PBCA-NPs were prepared by emulsion polymerization method, and characterized for morphology, particle size, drug encapsulation efficiency and loading efficiency. The formulation was optimized using central composite design and response surface methodology. In vitro release study of VCR-PBCA-NPs was performed by dialysis technique. Model fitting was used to determine the kinetics and to discuss the mechanism. The nanoparticles were spherical and uniform with a mean diameter of (98.9 +/- 3.05) nm. The drug encapsulation efficiency and loading efficiency were (55.23 +/- 0.96)% and (7.87 +/- 0.11)%, respectively. In vitro release results showed that 63.66% of VCR was released from VCR-PBCA-NPs in 4 h, and the Weibull model fitted VCR release pattern best. The VCR-PBCA-NPs prepared in this study showed sustained release compared with VCR solution.

A detailed view of microparticle formation by in-process monitoring of the glass transition temperature.

PubMed

Vay, Kerstin; Frieß, Wolfgang; Scheler, Stefan

2012-06-01

Biodegradable poly(D,L-lactide-co-glycolide) microspheres were prepared by a well-controlled emulsion solvent extraction/evaporation process. The objective of this study was to investigate how drug release can be modified by changing the morphology of the polymer matrix. The matrix structure was controlled by the preparation temperature which was varied between 10 and 35 °C, thus changing the 4 weeks release pattern from almost linear kinetics to a sigmoidal profile with a distinct lag phase and furthermore decreasing the encapsulation efficiency. By monitoring the glass transition temperature during the extraction process, it was shown that the preparation temperature determines the particle morphology by influencing the time span in which the polymer chains were mobile and flexible during the extraction process. Further factors determining drug release were found to be the molecular weight of the polymer and the rate of solvent removal. The latter, however, has also influence on the encapsulation efficiency with slow removal causing a higher drug loss. A secondary modification of the outer particle structure could be achieved by ethanolic post-treatment of the particles, which caused an extension of the lag phase and subsequently an accelerated drug release. Copyright © 2012. Published by Elsevier B.V.

Development of a Controlled Release of Salicylic Acid Loaded Stearic Acid-Oleic Acid Nanoparticles in Cream for Topical Delivery

PubMed Central

Woo, J. O.; Misran, M.; Lee, P. F.; Tan, L. P.

2014-01-01

Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs) with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release. PMID:24578624

Nano-particle modified stationary phases for high-performance liquid chromatography.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Connolly, Damian; He, Xiaoyun; Floris, Patrick; Duffy, Emer; Paull, Brett

2013-08-07

This review covers the latest developments and applications of nano-materials in stationary phase development for various modes of high-performance liquid chromatography. Specific attention is placed upon the development of new composite phases, including the synthetic and immobilisation strategies used, to produce either encapsulated nano-particles, or surface attached nano-particles, layers, coatings and other structures. The resultant chromatographic applications, where applicable, are discussed with comment upon enhanced selectivity and/or efficiency of the nano-particle modified phases, where such effects have been identified. In the main this review covers developments over the past five years and is structured according to the nature of the nano-particles themselves, including carbonaceous, metallic, inorganic, and organopolymer based materials.

Effect of a controlled-release drug delivery system made of oleanolic acid formulated into multivesicular liposomes on hepatocellular carcinoma in vitro and in vivo

PubMed Central

Luo, Yuling; Liu, Zhongbing; Zhang, Xiaoqin; Huang, Juan; Yu, Xin; Li, Jinwei; Xiong, Dan; Sun, Xiaoduan; Zhong, Zhirong

2016-01-01

The aim of the present study was to develop a novel dosage form of multivesicular liposomes for oleanolic acid (OA) to overcome its poor solubility, prolong therapeutic drug levels in the blood, and enhance the antitumor effect on hepatocellular carcinoma. OA-encapsulated multivesicular liposomes (OA-MVLs) were prepared by a double-emulsion method, and the formulation was optimized by the central composite design. The morphology, particle size, and drug-loading efficiency of OA-MVLs were investigated. Furthermore, OA-MVLs were also characterized both in vitro and in vivo. The results showed that OA-MVLs were spherical particles with an average particle size of 11.57 μm and an encapsulation efficiency of 82.3%±0.61%. OA-MVLs exhibited a sustained-release pattern in vitro, which was fitted to Ritger–Peppas equation. OA-MVLs inhibited the growth of human HepG2 cells which was confirmed by the MTT assay and fluorescence microscopy detection. The in vivo release of OA from OA-MVLs exhibited a sustained manner, indicating a longer circulation time compared to OA solution. The in vivo toxicity study indicated that medium-dose OA-MVLs exerted no toxic effect on the hosts. Importantly, OA-MVLs suppressed the growth of murine H22 hepatoma and prolonged the survival of tumor-bearing mice. In conclusion, the poorly soluble OA could be encapsulated into MVLs to form a novel controlled-release drug delivery system. The present study may hold promise for OA-MVLs as a new dosage form for sustained-release drug delivery in cancer therapy. PMID:27471381

Effect of Encapsulation on Antimicrobial Activity of
Herbal Extracts with Lysozyme

PubMed Central

Matouskova, Petra; Bokrova, Jitka; Benesova, Pavla

2016-01-01

Summary Resistance of microorganisms to antibiotics has increased. The use of natural components with antimicrobial properties can be of great significance to reduce this problem. The presented work is focused on the study of the effect of encapsulation of selected plant and animal antimicrobial substances (herbs, spices, lysozyme and nisin) on their activity and stability. Antimicrobial components were packaged into liposomes and polysaccharide particles (alginate, chitosan and starch). Antimicrobial activity was tested against two Gram-positive (Bacillus subtilis and Micrococcus luteus) and two Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Encapsulation was successful in all types of polysaccharide particles and liposomes. The prepared particles exhibited very good long-term stability, especially in aqueous conditions. Antimicrobial activity was retained in all types of particles. Liposomes with encapsulated herb and spice extracts exhibited very good inhibitory effect against all tested bacterial strains. Most of herbal extracts had very good antimicrobial effect against the tested Gram-negative bacterial strains, while Gram-positive bacteria were more sensitive to lysozyme particles. Thus, particles with co-encapsulated herbs and lysozyme are more active against different types of bacteria, and more stable and more effective during long-term storage. Particles with encapsulated mixture of selected plant extracts and lysozyme could be used as complex antimicrobial preparation with controlled release in the production of food and food supplements, pharmaceutical and cosmetic industries. PMID:27956862

AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery.

PubMed

Aravind, Athulya; Jeyamohan, Prashanti; Nair, Remya; Veeranarayanan, Srivani; Nagaoka, Yutaka; Yoshida, Yasuhiko; Maekawa, Toru; Kumar, D Sakthi

2012-11-01

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery. Copyright © 2012 Wiley Periodicals, Inc.

Asymmetrical Polyhedral Configuration of Giant Vesicles Induced by Orderly Array of Encapsulated Colloidal Particles

PubMed Central

Natsume, Yuno; Toyota, Taro

2016-01-01

Giant vesicles (GVs) encapsulating colloidal particles by a specific volume fraction show a characteristic configuration under a hypertonic condition. Several flat faces were formed in GV membrane with orderly array of inner particles. GV shape changed from the spherical to the asymmetrical polyhedral configuration. This shape deformation was derived by entropic interaction between inner particles and GV membrane. Because a part of inner particles became to form an ordered phase in the region neighboring the GV membrane, free volume for the other part of particles increased. Giant vesicles encapsulating colloidal particles were useful for the model of “crowding effect” which is the entropic interaction in the cell. PMID:26752650

Asymmetrical Polyhedral Configuration of Giant Vesicles Induced by Orderly Array of Encapsulated Colloidal Particles.

PubMed

Natsume, Yuno; Toyota, Taro

2016-01-01

Giant vesicles (GVs) encapsulating colloidal particles by a specific volume fraction show a characteristic configuration under a hypertonic condition. Several flat faces were formed in GV membrane with orderly array of inner particles. GV shape changed from the spherical to the asymmetrical polyhedral configuration. This shape deformation was derived by entropic interaction between inner particles and GV membrane. Because a part of inner particles became to form an ordered phase in the region neighboring the GV membrane, free volume for the other part of particles increased. Giant vesicles encapsulating colloidal particles were useful for the model of "crowding effect" which is the entropic interaction in the cell.

Aerosol delivery of liposome-encapsulated ciprofloxacin: aerosol characterization and efficacy against Francisella tularensis infection in mice.

PubMed

Conley, J; Yang, H; Wilson, T; Blasetti, K; Di Ninno, V; Schnell, G; Wong, J P

1997-06-01

The aerosol delivery of liposome-encapsulated ciprofloxacin by using 12 commercially available jet nebulizers was evaluated in this study. Aerosol particles containing liposome-encapsulated ciprofloxacin generated by the nebulizers were analyzed with a laser aerodynamic particle sizer. Mean mass aerodynamic diameters (MMADs) and geometric standard deviations (GSDs) were determined, and the drug contents of the sampling filters from each run onto which aerosolized liposome-encapsulated ciprofloxacin had been deposited were analyzed spectrophotometrically. The aerosol particles of liposome-encapsulated ciprofloxacin generated by these nebulizers ranged from 1.94 to 3.5 microm, with GSDs ranging from 1.51 to 1.84 microm. The drug contents of the sampling filters exposed for 1 min to aerosolized liposome-encapsulated ciprofloxacin range from 12.7 to 40.5 microg/ml (0.06 to 0.2 mg/filter). By using the nebulizer selected on the basis of most desirable MMADs, particle counts, and drug deposition, aerosolized liposome-encapsulated ciprofloxacin was used for the treatment of mice infected with 10 times the 50% lethal dose of Francisella tularensis. All mice treated with aerosolized liposome-encapsulated ciprofloxacin survived the infection, while all ciprofloxacin-treated or untreated control mice succumbed to the infection (P < 0.001). These results suggest that aerosol delivery of liposome-encapsulated ciprofloxacin to the lower respiratory tract is feasible and that it may provide an effective therapy for the treatment of respiratory tract infections.

Enhanced in Vitro Anti-Tumor Activity of 5-Azacytidine by Entrapment into Solid Lipid Nanoparticles

PubMed Central

Jahanfar, Farhad; Hasani, Akbar; Shanebandi, Dariush; Rahmati, Mohammad; Hamishehkar, Hamed

2016-01-01

Purpose: In this study the effectiveness of encapsulating of 5-azacytidine into the lipid nanoparticles was investigated and in vitro effect of encapsulated 5-azacytidine studied on MCF-7 cell lines Methods: 5-azacytidine -loaded solid lipid nanoparticles were produced by double emulsification (w/o/w) method by using stearic acid as lipid matrix, soy lecithin and poloxamer 407 as surfactant and co-surfactant respectively. Particle size, zeta potential, surface morphology, entrapment efficiency and kinetic of drug release were studied. In vitro effect of 5-azacytidine on MCF-7 cell line studied by MTT assay, DAPI staining, Rhodamine B relative uptake, and also Real time RT-PCR was performed for studying difference effect of free and encapsulated drug on expression of RARß2 gene. Results: The formulation F5 with 55.84±0.46 % of entrapment efficiency shows zero order kinetic of drug release and selected for in vitro studies; the cytotoxicity of free drug and encapsulated drug in 48 h of incubation have significant difference. DAPI staining shows morphology of apoptotic nucleus in both free and encapsulated drug, Rhodamine B labeled SLNs show time dependency and accumulation of SLNs in cytoplasm. Real time qRT-PCR doesn’t show any significant difference (p>0.05) in expression of RARß2 gene in both cells treated with free or encapsulated drug. Conclusion: The results of the present study indicated that the entrapment of 5-azacytidine into SLNs enhanced its cytotoxicity performance and may pave a way for the future design of a desired dosage form for 5-azacytidine. PMID:27766220

Spray-dried structured lipid containing long-chain polyunsaturated fatty acids for use in infant formulas.

PubMed

Nagachinta, Supakana; Akoh, Casimir C

2013-10-01

Human milk fat (HMF) analogs are structured lipids (SLs) modified to have palmitic acid content at the sn-2 position of the triacylglycerol (TAG) and fatty acid composition comparable to HMF. Some of these SLs are also designed to incorporate long-chain polyunsaturated fatty acids (LCPUFAs) because of their important role in infant development. In this study, Maillard reaction products (MRPs), obtained from heated whey protein isolates and corn syrup solids (CSS) solution, were used as encapsulants for microencapsulation of 2 enzymatically synthesized SLs for infant formula applications. The encapsulated SL powders were obtained through spray-drying and evaluated in terms of their microencapsulation efficiency, chemical and physical properties, oxidative stability, and dispersibility. The microencapsulation efficiency of the SLs was 90%. Dispersibility test using particle size measurement demonstrated that these powders dispersed quickly into a homogeneous suspension. The encapsulated SL powders had low peroxide and thiobarbituric acid-reactive substances values. Lower oxidative stability was obtained in the powder containing SL with a higher degree of unsaturation and a lower concentration of tocopherols. The results demonstrated that the degree of fatty acid unsaturation and concentration of endogenous antioxidant in starting oils influenced the oxidative stability of the encapsulated SLs. © 2013 Institute of Food Technologists®

Fluorescence Characterization of Gold Modified Liposomes with Antisense N-myc DNA Bound to the Magnetisable Particles with Encapsulated Anticancer Drugs (Doxorubicin, Ellipticine and Etoposide).

PubMed

Skalickova, Sylvie; Nejdl, Lukas; Kudr, Jiri; Ruttkay-Nedecky, Branislav; Jimenez, Ana Maria Jimenez; Kopel, Pavel; Kremplova, Monika; Masarik, Michal; Stiborova, Marie; Eckschlager, Tomas; Adam, Vojtech; Kizek, Rene

2016-02-25

Liposome-based drug delivery systems hold great potential for cancer therapy. The aim of this study was to design a nanodevice for targeted anchoring of liposomes (with and without cholesterol) with encapsulated anticancer drugs and antisense N-myc gene oligonucleotide attached to its surface. To meet this main aim, liposomes with encapsulated doxorubicin, ellipticine and etoposide were prepared. They were further characterized by measuring their fluorescence intensity, whereas the encapsulation efficiency was estimated to be 16%. The hybridization process of individual oligonucleotides forming the nanoconstruct was investigated spectrophotometrically and electrochemically. The concentrations of ellipticine, doxorubicin and etoposide attached to the nanoconstruct in gold nanoparticle-modified liposomes were found to be 14, 5 and 2 µg·mL(-1), respectively. The study succeeded in demonstrating that liposomes are suitable for the transport of anticancer drugs and the antisense oligonucleotide, which can block the expression of the N-myc gene.

Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo

NASA Astrophysics Data System (ADS)

Gou, Maling; Men, Ke; Shi, Huashan; Xiang, Mingli; Zhang, Juan; Song, Jia; Long, Jianlin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, Zhiyong

2011-04-01

Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 +/- 0.011) with a mean particle size of 27.3 +/- 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 +/- 1.02%, and drug loading of 12.95 +/- 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t1/2 and AUC of curcuminin vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesisin vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cellsin vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg-1curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

Development of PEG-PLGA based Intravenous Low Molecular Weight Heparin (LMWH) Nanoparticles Intended to Treat Venous Thrombosis.

PubMed

Jogala, Satheesh; Rachamalla, Shyam Sunder; Aukunuru, Jithan

2016-01-01

Anticoagulant therapy is effective in the treatment of DVT. In this regard, LMWH demonstrated significant promise. It is widely used clinically. The goal of this study was to prepare and evaluate intravenous sustained release stealth nanoparticles encapsulating LMWH using PLGA (polylactidecoglycolide) and different grades of PEG (poly ethylene glycols). The nanoparticles were prepared using w/o/w solvent evaporation technique. Prepared nanoparticles were evaluated for particle size, encapsulation efficiency, in-vitro drug release, anti-thrombotic activity in venous thrombosis rat model, estimation of aPTT, tissue bio-distribution studies and stability. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies confirmed the formation of smooth spherical particles. FTIR study reveals successful coating of PEG on the nanoparticles. DSC and XRD results demonstrated that drug changed its physical form in the formulation. The encapsulation efficiency was 63-74%. In vitro drug release was 57-75% for 48 hrs. Macrophage uptake of LMWH with pegylated nanoparticles was less compared to conventional PLGA nanoparticles. In vivo drug release was sustained for 48hrs; Optimized formulation exhibited good enhancement in pharmacokinetic parameters when compared to free drug solution. In vivo sustained release was also demonstrated with antithrombotic activity as well aPTT activity. Optimized formulation demonstrated significant stability, excellent antithrombotic activity in venous thrombosis rat model, improved aPTT levels when compared to free drug solution. An effective stealth LMWH nanoparticle formulation to treat venous thrombosis was successfully developed using w/o/w solvent evaporation technique.

Influence of the Formulation Parameters on the Particle Size and Encapsulation Efficiency of Resveratrol in PLA and PLA-PEG Blend Nanoparticles: A Factorial Design.

PubMed

Lindner, Gabriela da Rocha; Dalmolin, Luciana Facco; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

2015-12-01

Polymeric nanoparticles are colloidal systems that promote protection and modification of physicochemical characteristics of a drug and that also ensure controlled and extended drug release. This paper reports a 2(3) factorial design study to optimize poly(lactide) (PLA) and poly(lactide)-polyethylene glycol (PLA-PEG) blend nanoparticles containing resveratrol (RVT) for prolonged release. The independent variables analyzed were solvent composition, surfactant concentration and ratio of aqueous to organic phase (two levels each factor). Mean particle size and RVT encapsulation efficiency were set as the dependent variables. The selected optimized parameters were set as organic phase comprised of a mixture of dichloromethane and ethyl acetate, 1% of surfactant polyvinyl alcohol and a 3:1 ratio of aqueous to organic phase, for both PLA and PLA-PEG blend nanoparticles. This formulation originated nanoparticles with size of 228 ± 10 nm and 185 ± 70 nm and RVT encapsulation efficiency of 82 ± 10% and 76 ± 7% for PLA and PLA-PEG blend nanoparticles, respectively. The in vitro release study showed a biphasic pattern with prolonged RVT release and PEG did not influence the RVT release. The in vitro release data were in favor of Higuchi-diffusion kinetics for both nanoformulations and the Kossmeyer-Peppas coefficient indicated that anomalous transport was the main release mechanism of RVT. PLA and PLA-PEG blend nanoparticles produced with single emulsion-solvent evaporation technology were found to be a promising approach for the incorporation of RVT and promoted its controlled release. The factorial design is a tool of great value in choosing formulations with optimized parameters.

Synthesis of protein-coated biocompatible methotrexate-loaded PLA-PEG-PLA nanoparticles for breast cancer treatment

PubMed Central

Massadeh, Salam; Alaamery, Manal; Al-Qatanani, Shatha; Alarifi, Saqer; Bawazeer, Shahad; Alyafee, Yusra

2016-01-01

Background PLA-PEG-PLA triblock polymer nanoparticles are promising tools for targeted dug delivery. The main aim in designing polymeric nanoparticles for drug delivery is achieving a controlled and targeted release of a specific drug at the therapeutically optimal rate and choosing a suitable preparation method to encapsulate the drug efficiently, which depends mainly on the nature of the drug (hydrophilic or hydrophobic). In this study, methotrexate (MTX)-loaded nanoparticles were prepared by the double emulsion method. Method Biodegradable polymer polyethylene glycol-polylactide acid tri-block was used with poly(vinyl alcohol) as emulsifier. The resulting methotrexate polymer nanoparticles were coated with bovine serum albumin in order to improve their biocompatibility. This study focused on particle size distribution, zeta potential, encapsulation efficiency, loading capacity, and in vitro drug release at various concentrations of PVA (0.5%, 1%, 2%, and 3%). Results Reduced particle size of methotrexate-loaded nanoparticles was obtained using lower PVA concentrations. Enhanced encapsulation efficiency and loading capacity was obtained using 1% PVA. FT-IR characterization was conducted for the void polymer nanoparticles and for drug-loaded nanoparticles with methotrexate, and the protein-coated nanoparticles in solid state showed the structure of the plain PEG-PLA and the drug-loaded nanoparticles with methotrexate. The methotrexate-loaded PLA-PEG-PLA nanoparticles have been studied in vitro; the drug release, drug loading, and yield are reported. Conclusion The drug release profile was monitored over a period of 168 hours, and was free of burst effect before the protein coating. The results obtained from this work are promising; this work can be taken further to develop MTX based therapies.

Identifying lipidic emulsomes for improved oxcarbazepine brain targeting: In vitro and rat in vivo studies.

PubMed

El-Zaafarany, Ghada M; Soliman, Mahmoud E; Mansour, Samar; Awad, Gehanne A S

2016-04-30

Lipid-based nanovectors offer effective carriers for brain delivery by improving drug potency and reducing off-target effects. Emulsomes are nano-triglyceride (TG) carriers formed of lipid cores supported by at least one phospholipid (PC) sheath. Due to their surface active properties, PC forms bilayers at the aqueous interface, thereby enabling encapsulated drug to benefit from better bioavailability and stability. Emulsomes of oxcarbazepine (OX) were prepared, aimed to offer nanocarriers for nasal delivery for brain targeting. Different TG cores (Compritol(®), tripalmitin, tristearin and triolein) and soya phosphatidylcholine in different amounts and ratios were used for emulsomal preparation. Particles were modulated to generate nanocarriers with suitable size, charge, encapsulation efficiency and prolonged release. Cytotoxicity and pharmacokinetic studies were also implemented. Nano-spherical OX-emulsomes with maximal encapsulation of 96.75% were generated. Stability studies showed changes within 30.6% and 11.2% in the size and EE% after 3 months. MTT assay proved a decrease in drug toxicity by its encapsulation in emulsomes. Incorporation of OX into emulsomes resulted in stable nanoformulations. Tailoring emulsomes properties by modulating the surface charge and particle size produced a stable system for the lipophilic drug with a prolonged release profile and mean residence time and proved direct nose-to-brain transport in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

Development, Characterization and Evaluation of Solid Lipid Nanoparticles as a potential Anticancer Drug Delivery System

NASA Astrophysics Data System (ADS)

Patel, Meghavi

Solid lipid nanoparticles (SLNs) consist of spherical solid lipid particles in the nanometer size range, which are dispersed in water or in an aqueous surfactant solution. SLN technology represents a promising new approach to deliver hydrophilic as well as lipophilic drugs. The commercialization of SLN technology remains limited despite numerous efforts from researchers. The purpose of this research was to advance SLN preparation methodology by investigating the feasibility of preparing glyceryl monostearate (GMS) nanoparticles by using three preparation methods namely microemulsion technique, magnetic stirring technique and temperature modulated solidification technique of which the latter two were developed in our laboratory. An anticancer drug 5-fluorouracil was incorporated in the SLNs prepared via the temperature modulated solidification process. Optimization of the magnetic stirring process was performed to evaluate how the physicochemical properties of the SLN was influenced by systematically varying process parameters including concentration of the lipid, concentration of the surfactant, type of surfactant, time of stirring and temperature of storage. The results demonstrated 1:2 GMS to tween 80 ratio, 150 ml dispersion medium and 45 min stirring at 4000 RPM speed provided an optimum formulation via the temperature modulated solidification process. SLN dispersions were lyophilized to stabilize the solid lipid nanoparticles and the lyophilizates exhibited good redispersibility. The SLNs were characterized by particle size analysis via dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), drug encapsulation efficiency and in vitro drug release studies. Particle size of SLN dispersion prepared via the three preparation techniques was approximately 66 nm and that of redispersed lyophilizates was below 500 nm. TEM images showed spherical to oval particles that were less dense in the core with a well-defined shell and the particle size was in agreement with the particle size analysis data obtained by DLS. DSC thermograms of the lyophilized SLNs indicate a reduction in the crystallinity order of GMS particles. The drug encapsulation efficiency was found to be approximately 30%. In vitro drug release studies from redispersed lyophilized SLNs showed that 17 % of the encapsulated drug was released within 2 h. The SLNs prepared in our lab demonstrated characteristics that can potentially be utilized in an anticancer drug delivery system. Future in vitro cell culture and in vivo animal model studies will delineate compatibility and utility of these formulations in biological systems.

Aerosol delivery of liposome-encapsulated ciprofloxacin: aerosol characterization and efficacy against Francisella tularensis infection in mice.

PubMed Central

Conley, J; Yang, H; Wilson, T; Blasetti, K; Di Ninno, V; Schnell, G; Wong, J P

1997-01-01

The aerosol delivery of liposome-encapsulated ciprofloxacin by using 12 commercially available jet nebulizers was evaluated in this study. Aerosol particles containing liposome-encapsulated ciprofloxacin generated by the nebulizers were analyzed with a laser aerodynamic particle sizer. Mean mass aerodynamic diameters (MMADs) and geometric standard deviations (GSDs) were determined, and the drug contents of the sampling filters from each run onto which aerosolized liposome-encapsulated ciprofloxacin had been deposited were analyzed spectrophotometrically. The aerosol particles of liposome-encapsulated ciprofloxacin generated by these nebulizers ranged from 1.94 to 3.5 microm, with GSDs ranging from 1.51 to 1.84 microm. The drug contents of the sampling filters exposed for 1 min to aerosolized liposome-encapsulated ciprofloxacin range from 12.7 to 40.5 microg/ml (0.06 to 0.2 mg/filter). By using the nebulizer selected on the basis of most desirable MMADs, particle counts, and drug deposition, aerosolized liposome-encapsulated ciprofloxacin was used for the treatment of mice infected with 10 times the 50% lethal dose of Francisella tularensis. All mice treated with aerosolized liposome-encapsulated ciprofloxacin survived the infection, while all ciprofloxacin-treated or untreated control mice succumbed to the infection (P < 0.001). These results suggest that aerosol delivery of liposome-encapsulated ciprofloxacin to the lower respiratory tract is feasible and that it may provide an effective therapy for the treatment of respiratory tract infections. PMID:9174185

Transgene and immune gene expression following intramuscular injection of Atlantic salmon (Salmo salar L.) with DNA-releasing PLGA nano- and microparticles.

PubMed

Hølvold, Linn Benjaminsen; Fredriksen, Børge N; Bøgwald, Jarl; Dalmo, Roy A

2013-09-01

The use of poly-(D,L-lactic-co-glycolic) acid (PLGA) particles as carriers for DNA delivery has received considerable attention in mammalian studies. DNA vaccination of fish has been shown to elicit durable transgene expression, but no reports exist on intramuscular administration of PLGA-encapsulated plasmid DNA (pDNA). We injected Atlantic salmon (Salmo salar L.) intramuscularly with a plasmid vector containing a luciferase (Photinus pyralis) reporter gene as a) naked pDNA, b) encapsulated into PLGA nano- (~320 nm) (NP) or microparticles (~4 μm) (MP), c) in an oil-based formulation, or with empty particles of both sizes. The ability of the different pDNA-treatments to induce transgene expression was analyzed through a 70-day experimental period. Anatomical distribution patterns and depot effects were determined by tracking isotope labeled pDNA. Muscle, head kidney and spleen from all treatment groups were analyzed for proinflammatory cytokines (TNF-α, IL-1β), antiviral genes (IFN-α, Mx) and cytotoxic T-cell markers (CD8, Eomes) at mRNA transcription levels at days 1, 2, 4 and 7. Histopathological examinations were performed on injection site samples from days 2, 7 and 30. Injection of either naked pDNA or the oil-formulation was superior to particle treatments for inducing transgene expression at early time-points. Empty particles of both sizes were able to induce proinflammatory immune responses as well as degenerative and inflammatory pathology at the injection site. Microparticles demonstrated injection site depots and an inflammatory pathology comparable to the oil-based formulation. In comparison, the distribution of NP-encapsulated pDNA resembled that of naked pDNA, although encapsulation into NPs significantly elevated the expression of antiviral genes in all tissues. Together the results indicate that while naked pDNA is most efficient for inducing transgene expression, the encapsulation of pDNA into NPs up-regulates antiviral responses that could be of benefit to DNA vaccination. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of droplet microfluidic platforms for the synthesis of monodisperse lipid vesicles and polymer particles

NASA Astrophysics Data System (ADS)

Teh, Shia-Yen

This body of work presents my approaches to the design and development of microfluidic platforms for synthesizing monodisperse polymer particles and phospholipid vesicles. There is interest in both of these particles for use in a variety of biomedical applications. Poly(D,L-lactide-co-glycolic acid) (PLGA) particles in particular have been sought out as vehicles for drug delivery due to their biocompatibility and because the rate of degradation -- hence cargo release - can be controlled. On the other hand, liposomes possess membrane structures resembling that of cells, an ability to adopt both hydrophilic and hydrophobic molecules, and are easily functionalized, which make lipid vesicles the ideal candidate for applications ranging from targeted therapeutic delivery to formation of artificial cells. However, current methods of production for both of these particles result in a wide range of sizes and poor cargo uptake efficiency. We address these challenges by utilizing a flow focusing droplet generation design, which allows for fine control over droplet size and improves encapsulation efficiencies. The size of these droplets can be determined by channel geometry and the ratio of fluid flow rates. I will discuss the work I have done to improve upon current technologies to form nano- to micrometer sized PLGA particles and cell-sized lipid vesicles. Solvent evaporation and solvent extraction methods were implemented and tested in several device designs to optimize the formation process. The particles produced were characterized for their stability, size variation, and ability to encapsulate a model drug. The release profiles of PLGA particles were also measured to determine the length of delivery. In addition, I worked on the generation of monodisperse lipid vesicles to investigate the application of liposomes as an artificial cell. As a proof of principle, expression of green fluorescent protein (GFP) was successfully carried out in the lipid vesicles. This demonstrates the versatility of the microfluidic device for generating a range of particles of controlled size for therapeutic agent delivery and artificial cell applications.

High-oil-load encapsulation of medium-chain triglycerides and D-limonene mixture in modified starch by spray drying.

PubMed

Paramita, Vita; Furuta, Takeshi; Yoshii, Hidefumi

2012-02-01

Oil mixtures of medium-chain triglycerides (MCT) and D-limonene in mixing ratios from 10 to 100 wt% were encapsulated in modified starch (wall material) by spray drying to produce oil-rich powders. The oil load (mass ratio of oil mixture to wall material) of the infeed emulsion markedly influenced the properties of the infeed liquid and the characteristics of the resulting powder. The viscosity of the infeed liquid and the particle size of the powder exponentially decreased with increasing oil load, while the emulsion droplet size in the infeed liquid increased. In addition, retention of D-limonene during spray drying also decreased markedly with increasing oil load. Irrespective of the different oil loads and concentrations of the wall material, D-limonene retention was well correlated with the emulsion droplet diameter of the infeed liquid. The encapsulation efficiency of the oil mixture exhibited a maximum value (almost 100%) at an oil load between 0.5 and 1.0, before decreasing at higher oil loads. At an oil load of 2.0, the encapsulation efficiency of D-limonene was reduced to almost zero, while around 40% of the initial MCT was encapsulated in the powder. The increase in oil load also led to increased amounts of surface oil of MCT and D-limonene in the resulting powder due to the increasing emulsion droplet diameter of the infeed liquids. This study proposes the microencapsulation of medium-chain triglycerides under high-oil-load conditions by spray drying. The powders prepared by this process provide significant benefits in terms of rapid energy conversion after consumption without accumulation in the body. Important quality factors of the powder products such as the encapsulation efficiency and the amount of surface oil were examined to understand the optimum process conditions for spray drying. © 2012 Institute of Food Technologists®

Solidification of liposomes by freeze-drying: the importance of incorporating gelatin as interior support on enhanced physical stability.

PubMed

Guan, Peipei; Lu, Yi; Qi, Jianping; Niu, Mengmeng; Lian, Ruyue; Wu, Wei

2015-01-30

The main purpose of this study was to investigate the effect of gelatin as interior support on the physical stability of freeze-dried liposomes. Anticancer agent paclitaxel (PTX) was selected as a model drug. Freeze-dried liposomes containing interior gelatin support (GLs) were prepared by thin-film dispersion/freeze-drying method. Several properties of the GLs, including entrapment efficiency, particle size and gelation temperature, were extensively characterized. Encapsulation efficiency of conventional liposomes (CLs) and liposomes containing lyoprotectants as interior support dropped to lower than 20% after reconstitution, while GLs still maintained an entrapment efficiency of over 84%. Scanning electron microscopy revealed well preserved liposomal structure of GLs after reconstitution. Meanwhile, the particle size and entrapment efficiency of GLs were also well preserved after reconstitution. In contrary, deformation of CLs and recrystallization of PTX were observed, as well as significant changes in particle size and entrapment efficiency. Taken together, interior gelatin support obviously enhanced the physical stability of liposomes against the lyophilization stress. Copyright © 2014 Elsevier B.V. All rights reserved.

Fabrication, characterization, and evaluation of microsponge delivery system for facilitated fungal therapy

PubMed Central

Moin, Afrasim; Deb, Tamal K.; Osmani, Riyaz Ali M.; Bhosale, Rohit R.; Hani, Umme

2016-01-01

Objective: The rationale behind present research vocation was to develop and investigate a novel microsponge based gel as a topical carrier for the prolonged release and cutaneous drug deposition of fluconazole (FLZ); destined for facilitated fungal therapy. Materials and Methods: Microsponges were prepared using quasi-emulsion solvent diffusion method using Eudragit S-100. In the direction of optimization, the effect of formulation variables (drug-polymer ratio and amount of emulsifier) and diverse factors affecting physical characteristics of microsponge were investigated as well. Fabricated microsponges were characterized by differential scanning calorimetry, Fourier transform-infrared, scanning electron microscopy (SEM), particle size analysis, and also evaluated for drug content, encapsulation efficiency, in vitro drug release and in vitro antifungal activity. Results: Compatibility studies results reflected no sign of any chemical interaction between the drug and polymers used. Whereas, varied drug-polymer ratios and emulsifier concentration indicated significant effect on production yield, drug content, encapsulation efficiency, particle size and drug release. Spherical microsponges with a porous surface and 29.327 ± 0.31 μm mean particle size were evident from SEM micrographs. In vitro release outcomes, from microsponge loaded gels depicted that F1 formulation was more efficient to give extended drug release of 85.38% at the end of 8 h, while conventional formulation by releasing 83.17% of drug got exhausted incredibly earlier at the end of 4 h merely. Moreover, microsponge gels demonstrated substantial spreadability and extrudability along with promising antifungal activity. Conclusions: Fabricated microsponges would be impending pharmaceutical topical carriers of FLZ and a leading alternative to conventional therapy for efficient, safe and facilitated eradication of fungal infections. PMID:27057125

Facile fabrication of core-in-shell particles by the slow removal of the core and its use in the encapsulation of metal nanoparticles.

PubMed

Choi, Won San; Koo, Hye Young; Kim, Dong-Yu

2008-05-06

Core-in-shell particles with controllable core size have been fabricated from core-shell particles by means of the controlled core-dissolution method. These cores in inorganic shells were employed as scaffolds for the synthesis of metal nanoparticles. After dissolution of the cores, metal nanoparticles embedded in cores were encapsulated into the interior of shell, without any damage or change. This article describes a very simple method for deriving core-in-shell particles with controllable core size and encapsulation of nanoparticles into the interior of shell.

Drug particle size influence on enteric beads produced by a droplet extrusion/precipitation method.

PubMed

Cerdeira, A M; Gouveia, L F; Goucha, P; Almeida, A J

2000-01-01

The influence of drug particle size on the production of enteric beads by a polymer precipitation technique was investigated. Drug particle dimensions are known to play an important role in most microencapsulation techniques. Bead morphology was greatly influenced by drug particle size, and spherical shaped beads could only be obtained after size reduction of nimesulide crystals. This is confirmed by the angle of repose measurements, which show a significant decrease in theta values when beads are formulated with smaller drug particles. Furthermore, results show that drug encapsulation efficiency and in vitro drug release rates are also greatly dependent on both drug particle size and drug/polymer ratio in the initial suspension. Preparations containing 10.2 microm drug particles show a two-fold increase in the release rates when compared to those prepared with 40 microm particles.

Applying quality by design (QbD) concept for fabrication of chitosan coated nanoliposomes.

PubMed

Pandey, Abhijeet P; Karande, Kiran P; Sonawane, Raju O; Deshmukh, Prashant K

2014-03-01

In the present investigation, a quality by design (QbD) strategy was successfully applied to the fabrication of chitosan-coated nanoliposomes (CH-NLPs) encapsulating a hydrophilic drug. The effects of the processing variables on the particle size, encapsulation efficiency (%EE) and coating efficiency (%CE) of CH-NLPs (prepared using a modified ethanol injection method) were investigated. The concentrations of lipid, cholesterol, drug and chitosan; stirring speed, sonication time; organic:aqueous phase ratio; and temperature were identified as the key factors after risk analysis for conducting a screening design study. A separate study was designed to investigate the robustness of the predicted design space. The particle size, %EE and %CE of the optimized CH-NLPs were 111.3 nm, 33.4% and 35.2%, respectively. The observed responses were in accordance with the predicted response, which confirms the suitability and robustness of the design space for CH-NLP formulation. In conclusion, optimization of the selected key variables will help minimize the problems related to size, %EE and %CE that are generally encountered when scaling up processes for NLP formulations. The robustness of the design space will help minimize both intra-batch and inter-batch variations, which are quite common in the pharmaceutical industry.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes.

PubMed

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy ( 1 H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1 H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes

PubMed Central

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

Design, characterization, and in vitro cellular inhibition and uptake of optimized genistein-loaded NLC for the prevention of posterior capsular opacification using response surface methodology.

PubMed

Zhang, Wenji; Li, Xuedong; Ye, Tiantian; Chen, Fen; Sun, Xiao; Kong, Jun; Yang, Xinggang; Pan, Weisan; Li, Sanming

2013-09-15

This study was to design an innovative nanostructured lipid carrier (NLC) for drug delivery of genistein applied after cataract surgery for the prevention of posterior capsular opacification. NLC loaded with genistein (GEN-NLC) was produced with Compritol 888 ATO, Gelucire 44/14 and Miglyol 812N, stabilized by Solutol(®) HS15 by melt emulsification method. A 2(4) central composite design of 4 independent variables was performed for optimization. Effects of drug concentration, Gelucire 44/14 concentration in total solid lipid, liquid lipid concentration, and surfactant concentration on the mean particle size, polydispersity index, zeta potential and encapsulation efficiency were investigated. Analysis of variance (ANOVA) statistical test was used to assess the optimization. The optimized GEN-NLC showed a homogeneous particle size of 90.16 nm (with PI=0.33) of negatively charged surface (-25.08 mv) and high encapsulation efficiency (91.14%). Particle morphology assessed by TEM revealed a spherical shape. DSC analyses confirmed that GEN was mostly entrapped in amorphous state. In vitro release experiments indicated a prolonged and controlled genistein release for 72 h. In vitro growth inhibition assay showed an effective growth inhibition of GEN-NLCs on human lens epithelial cells (HLECs). Preliminary cellular uptake test proved a enhanced penetration of genistein into HLECs when delivered in NLC. Copyright © 2013 Elsevier B.V. All rights reserved.

Sustained Release of Green Tea Polyphenols from Liposomal Nanoparticles; Release Kinetics and Mathematical Modelling.

PubMed

Prakash Upputuri, Ravi Theaj; Azad Mandal, Abul Kalam

2017-01-01

Background: Green tea polyphenols (GTP) are known to have several health benefits. In spite of these benefits, its application as a therapeutic agent is limited due to some of its limitations such as stability, bioavailability, and biotransformation. To overcome these limitations, liposomal nanoparticles have been used as a carrier of the GTP. Objective: Encapsulation of GTP to the liposomal nanoparticles in order to achieve a sustained release of the GTP and to determine the drug release kinetics and the mechanism of the release. Materials and Methods: GTP encapsulated liposomal nanoparticles were prepared using phosphatidyl choline and cholesterol. The synthesized particles were characterized for their particle size and morphology. In vitro release studies were carried out, followed by drug release kinetics, and determining the mechanism of release. In vitro , antioxidant assay was determined following 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results: Atomic force microscope (AFM) and high resolution scanning electron microscope (HR SEM) images showed spherical particles of the size of 64.5 and 252 nm. An encapsulation efficiency as high as 77.7% was observed with GTP concentration of 5 mg.mL -1 . In vitro release studies showed that the loading concentrations of GTP were independent to the cumulative percentage of the drug release. GTP release by varying the pH and temperature showed a direct correlation between the release parameter and the percentage of drug release. The higher the pH and temperature, the higher was the percentage of the drug release. The release data showed a good correlation with Zero order kinetics and the mechanism of the release being anomalous mode. Radical scavenging activity of the released GTP showed a potent scavenging activity. Conclusion: GTP encapsulated liposomal nanoparticles could be used as a delivery vehicle for achieving a sustained release.

Preparation and Characterization of SN-38-Encapsulated Phytantriol Cubosomes Containing α-Monoglyceride Additives.

PubMed

Ali, Md Ashraf; Noguchi, Shuji; Iwao, Yasunori; Oka, Toshihiko; Itai, Shigeru

2016-01-01

SN-38 is a potent active metabolite of irinotecan that has been considered as an anticancer candidate. However, the clinical development of this compound has been hampered by its poor aqueous solubility and chemical instability. In this study, we developed SN-38-encapsulated cubosomes to resolve these problems. Six α-monoglyceride additives, comprising monocaprylin, monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin, were used to prepare phytantriol (PHYT) cubosomes by probe sonication. The mean particle size, polydispersity index, and zeta potential values of these systems were around 190-230 nm, 0.19-0.25 and -17 to -22 mV, respectively. Small-angle X-ray scattering analyses confirmed that the SN-38-encapsulated cubosomes existed in the Pn̄3m space group both with and without the additives. The monoglyceride additives led to around a two-fold increase in the solubility of SN-38 compared with the PHYT cubosome. The drug entrapment efficiency of PHYT cubosomes with additives was greater than 97%. The results of a stability study at 25°C showed no dramatic changes in the particle size or polydispersity index characteristics, with at least 85% of the SN-38 existing in its active lactone form after 10 d, demonstrating the high stability of the cubosome nanoparticles. Furthermore, approximately 55% of SN-38 was slowly released from the cubosomes with additives over 96 h in vitro under physiological conditions. Taken together, these results show that the SN-38-encapsulated PHYT cubosome particles are promising drug carriers that should be considered for further in vivo experiments, including drug delivery to tumor cells using the enhanced permeability and retention effect.

Color-Tunable and High-Efficiency Dye-Encapsulated Metal-Organic Framework Composites Used for Smart White-Light-Emitting Diodes.

PubMed

Chen, Wenwei; Zhuang, Yixi; Wang, Le; Lv, Ying; Liu, Jianbin; Zhou, Tian-Liang; Xie, Rong-Jun

2018-05-25

Luminescent metal-organic frameworks (MOFs) (typically dye-encapsulated MOFs) are considered as one kind of interesting downconversion materials for white-light-emitting diodes (LEDs), but their quantum efficiency (QE) is not sufficient and thus needs to be significantly enhanced for practical applications. In this study, we successfully synthesized a series of Rh@bio-MOF-1 (Rh = rhodamine) with an internal QE as high as ∼79% via a solvothermal reaction followed by cation exchanges. The high efficiency of the Rh@bio-MOF-1 composites was attributable to the high intrinsic luminescent efficiency of the selected Rh dyes, the confinement effect in the bio-MOF-1 host, and the uniform particle morphology. The emission maximum could be continuously tuned from 550 to 610 nm by controlling the species and concentration of encapsulated dye molecules, showing great color tunability of the dye-encapsulated MOFs. The emission lifetime of ∼7 ns was 1 or 2 magnitude orders shorter than that of Ce 3+ - or Eu 2+ -doped inorganic phosphors, allowing for visible light communication (VLC). White LEDs, fabricated by using the synthesized Rh@bio-MOF-1 composite and inorganic phosphors of green (Ba,Sr) 2 SiO 4 :Eu 2+ and red CaAlSiN 3 :Eu 2+ , exhibited a high color rendering index of 80-94, a luminous efficacy of 94-156 lm/W, and an excellent stability in color point against drive current. The Rh@bio-MOF-1 composites with tunable colors, short emission lifetime, and high QE are expected to be used for smart white LEDs with multifunctions of both lighting and VLC.

Enhanced encapsulation and bioavailability of breviscapine in PLGA microparticles by nanocrystal and water-soluble polymer template techniques.

PubMed

Wang, Hong; Zhang, Guangxing; Ma, Xueqin; Liu, Yanhua; Feng, Jun; Park, Kinam; Wang, Wenping

2017-06-01

Poly (lactide-co-glycolide) (PLGA) microparticles are widely used for controlled drug delivery. Emulsion methods have been commonly used for preparation of PLGA microparticles, but they usually result in low loading capacity, especially for drugs with poor solubility in organic solvents. In the present study, the nanocrystal technology and a water-soluble polymer template method were used to fabricate nanocrystal-loaded microparticles with improved drug loading and encapsulation efficiency for prolonged delivery of breviscapine. Breviscapine nanocrystals were prepared using a precipitation-ultrasonication method and further loaded into PLGA microparticles by casting in a mold from a water-soluble polymer. The obtained disc-like particles were then characterized and compared with the spherical particles prepared by an emulsion-solvent evaporation method. X-ray powder diffraction (XRPD) and confocal laser scanning microscopy (CLSM) analysis confirmed a highly-dispersed state of breviscapine inside the microparticles. The drug form, loading percentage and fabrication techniques significantly affected the loading capacity and efficiency of breviscapine in PLGA microparticles, and their release performance as well. Drug loading was increased from 2.4% up to 15.3% when both nanocrystal and template methods were applied, and encapsulation efficiency increased from 48.5% to 91.9%. But loading efficiency was reduced as the drug loading was increased. All microparticles showed an initial burst release, and then a slow release period of 28days followed by an erosion-accelerated release phase, which provides a sustained delivery of breviscapine over a month. A relatively stable serum drug level for more than 30days was observed after intramuscular injection of microparticles in rats. Therefore, PLGA microparticles loaded with nanocrystals of poorly soluble drugs provided a promising approach for long-term therapeutic products characterized with preferable in vitro and in vivo performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Cellular trafficking and anticancer activity of Garcinia mangostana extract-encapsulated polymeric nanoparticles

PubMed Central

Pan-In, Porntip; Wanichwecharungruang, Supason; Hanes, Justin; Kim, Anthony J

2014-01-01

Garcinia mangostana Linn extract (GME) is a natural product that has received considerable attention in cancer therapy, and has the potential to reduce side effects of chemotherapeutics and improve efficacy. We formulated GME-encapsulated ethyl cellulose (GME-EC) and a polymer blend of ethyl cellulose and methyl cellulose (GME-EC/MC) nanoparticles. We achieved high drug-loading and encapsulation efficiency using a solvent-displacement method with particle sizes around 250 nm. Cellular uptake and accumulation of GME was higher for GME-encapsulated nanoparticles compared to free GME. In vitro cytotoxicity analysis showed effective anticancer activity of GME-EC and GME-EC/MC nanoparticles in HeLa cells in a dose-dependent manner. GME-EC/MC nanoparticles showed approximately twofold-higher anticancer activity compared to GME-EC nanoparticles, likely due to their enhanced bioavailability. GME-encapsulated nanoparticles primarily entered HeLa cells by clathrin-mediated endocytosis and trafficked through the endolysosomal pathway. As far as we know, this is the first report on the cellular uptake and intracellular trafficking mechanism of drug-loaded cellulose-based nanoparticles. In summary, encapsulation of GME using cellulose-derivative nanoparticles – GME-EC and GME-EC/MC nanoparticles – successfully improved the bioavailability of GME in aqueous solution, enhanced cellular uptake, and displayed effective anticancer activity. PMID:25125977

Fabrication and magnetic properties of Ni nanospheres encapsulated in a fullerene-like carbon.

PubMed

Pol, S V; Pol, V G; Frydman, A; Churilov, G N; Gedanken, A

2005-05-19

A very simple, efficient, and economical synthetic technique, which produces fascinating fullerene-like Ni-C (graphitic) core-shell nanostructures at a relatively low temperature, is reported. The thermal dissociation of Ni acetylacetonate is carried out in a closed vessel cell (Swagelok) that was heated at 700 degrees C for 3 h. The encapsulation of ferromagnetic Ni nanospheres into the onion structured graphitic layers is obtained in a one-stage, single precursor reaction, without a catalyst, that possesses interesting magnetic properties. The magnetoresistance (MR) property of Ni nanospheres encapsulated in a fullerene-like carbon was measured, which shows large negative MR, of the order of 10%. The proposed mechanism for the formation of the Ni-C core-shell system is based on the segregation and the surface flux formed in the Ni and carbon particles during the reaction under autogenic pressure at elevated temperature.

Magnetic separation of carbon-encapsulated Fe nanoparticles from thermally-treated wood char

Treesearch

Sung Phil Mun; Zhiyong Cai; Jilei Zhang

2013-01-01

Wood char,a by-product from the fast-pyrolysis process of southern yellow pine wood for bio-oil production, was carbonized with Fenano particles (FeNPs) as a catalyst to prepare carbon-encapsulated Fe nanoparticles. A magnetic separation method was tested to isolate carbon-encapsulated Fe nano particles from the carbonized char. X-ray diffraction pattern clearly shows...

Thermosensitive gemcitabine-magnetoliposomes for combined hyperthermia and chemotherapy

NASA Astrophysics Data System (ADS)

Ferreira, Roberta V.; da Mata Martins, Thaís Maria; Goes, Alfredo Miranda; Fabris, José D.; Cavalcante, Luis Carlos D.; Eugenio Fernandez Outon, Luis; Domingues, Rosana Z.

2016-02-01

The combination of magnetic hyperthermia therapy with the controlled release of chemotherapeutic agents in tumors may be an efficient therapeutic with few side effects because the bioavailability, tolerance and amount of the drug can be optimized. Here, we prepared magnetoliposomes consisting of magnetite nanoparticle cores and the anticancer drug gemcitabine encapsulated by a phospholipid bilayer. The potential of these magnetoliposomes for controlled drug release and cancer treatment via hyperthermic behavior was investigated. The magnetic nanoparticle encapsulation efficiency was dependent on the initial amount of magnetite nanoparticles present at the encapsulation stage; the best formulation was 66%. We chose this formulation to characterize the physicochemical properties of the magnetoliposomes and to encapsulate gemcitabine. The mean particle size and distribution were determined by dynamic light scattering (DLS), and the zeta potential was measured. The magnetoliposome formulations all had acceptable characteristics for systemic administration, with a mean size of approximately 150 nm and a polydispersity index <0.2. The magnetoliposomes were stable in aqueous suspension for at least one week, as determined by DLS. Temperature increases due to the dissipation energy of magnetoliposome suspensions subjected to an applied alternating magnetic field (AMF) were measured at different magnetic field intensities, and the values were appropriated for cancer treatments. The drug release profile at 37 °C showed that 17% of the gemcitabine was released after 72 h. Drug release from magnetoliposomes exposed to an AMF for 5 min reached 70%.

Formulation and characterization of nanoencapsulated curcumin using sodium caseinate and its incorporation in ice cream.

PubMed

Kumar, Deep Diyuti; Mann, Bimlesh; Pothuraju, Ramesh; Sharma, Rajan; Bajaj, Rajesh; Minaxi

2016-01-01

In the present investigation, the preparation and characterization of a curcumin nanoemulsion with milk protein (sodium caseinate) and its incorporation into ice cream were undertaken. Among the different combinations, the most stable formulation was observed using milk fat (8%), medium chain triglycerides (2%), curcumin (0.24%) and sodium caseinate (6%) with a mean particle size of 333.8 ± 7.18 nm, a zeta potential of -44.1 ± 0.72 mV and an encapsulation efficiency of 96.9 ± 0.28%. The effect of different processing conditions (heating, pH and ionic strength) on the particle size distribution and zeta potential of the nanoemulsion was evaluated. During heat treatment, the particle size of the nanoemulsion was increased from 333.8 ± 7.18 to 351.1 ± 4.04 nm. The nanoemulsion was destabilized at pH 4.6 and the particle size increased above and below pH 5.0. However, there was a slight increase in the particle size with a change in the ionic concentration. The release kinetics data suggested that in simulated gastro-intestinal digestion, the nanoemulsion was stable against pepsin digestion (a 5.25% release of curcumin), while pancreatic action led to a 16.12% release of curcumin from the nanoemulsion. Finally, our formulation was successfully incorporated into ice cream and the sensory attributes were evaluated. No significant difference was observed in the scores of the sensory attributes between the control and ice cream prepared with a curcumin nanoemulsion. Moreover, the encapsulation efficiency of the curcumin incorporated into the ice cream was 93.7%, which indicates that it can withstand the processing conditions. The findings suggest that ice cream is a suitable dairy product for the delivery of lipophilic bioactive components (curcumin) which can be used for therapeutic purposes.

Statistical optimization of controlled release microspheres containing cetirizine hydrochloride as a model for water soluble drugs.

PubMed

El-Say, Khalid M; El-Helw, Abdel-Rahim M; Ahmed, Osama A A; Hosny, Khaled M; Ahmed, Tarek A; Kharshoum, Rasha M; Fahmy, Usama A; Alsawahli, Majed

2015-01-01

The purpose was to improve the encapsulation efficiency of cetirizine hydrochloride (CTZ) microspheres as a model for water soluble drugs and control its release by applying response surface methodology. A 3(3) Box-Behnken design was used to determine the effect of drug/polymer ratio (X1), surfactant concentration (X2) and stirring speed (X3), on the mean particle size (Y1), percentage encapsulation efficiency (Y2) and cumulative percent drug released for 12 h (Y3). Emulsion solvent evaporation (ESE) technique was applied utilizing Eudragit RS100 as coating polymer and span 80 as surfactant. All formulations were evaluated for micromeritic properties and morphologically characterized by scanning electron microscopy (SEM). The relative bioavailability of the optimized microspheres was compared with CTZ marketed product after oral administration on healthy human volunteers using a double blind, randomized, cross-over design. The results revealed that the mean particle sizes of the microspheres ranged from 62 to 348 µm and the efficiency of entrapment ranged from 36.3% to 70.1%. The optimized CTZ microspheres exhibited a slow and controlled release over 12 h. The pharmacokinetic data of optimized CTZ microspheres showed prolonged tmax, decreased Cmax and AUC0-∞ value of 3309 ± 211 ng h/ml indicating improved relative bioavailability by 169.4% compared with marketed tablets.

Intracellular cargo delivery by virus capsid protein-based vehicles: From nano to micro.

PubMed

Gao, Ding; Lin, Xiu-Ping; Zhang, Zhi-Ping; Li, Wei; Men, Dong; Zhang, Xian-En; Cui, Zong-Qiang

2016-02-01

Cellular delivery is an important concern for the efficiency of medicines and sensors for disease diagnoses and therapy. However, this task is quite challenging. Self-assembly virus capsid proteins might be developed as building blocks for multifunctional cellular delivery vehicles. In this work, we found that SV40 VP1 (Simian virus 40 major capsid protein) could function as a new cell-penetrating protein. The VP1 protein could carry foreign proteins into cells in a pentameric structure. A double color structure, with red QDs (Quantum dots) encapsulated by viral capsids fused with EGFP, was created for imaging cargo delivery and release from viral capsids. The viral capsids encapsulating QDs were further used for cellular delivery of micron-sized iron oxide particles (MPIOs). MPIOs were efficiently delivered into live cells and controlled by a magnetic field. Therefore, our study built virus-based cellular delivery systems for different sizes of cargos: protein molecules, nanoparticles, and micron-sized particles. Much research is being done to investigate methods for efficient and specific cellular delivery of drugs, proteins or genetic material. In this article, the authors describe their approach in using self-assembly virus capsid proteins SV40 VP1 (Simian virus 40 major capsid protein). The cell-penetrating behavior provided excellent cellular delivery and should give a new method for biomedical applications. Copyright © 2015 Elsevier Inc. All rights reserved.

Insulin-egg yolk dispersions in self microemulsifying system.

PubMed

Singnurkar, P S; Gidwani, S K

2008-11-01

Formulation of insulin into a microemulsion very often presents a physicochemical instability during their preparation and storage. In order to overcome this lack of stability and facilitate the handling of these colloidal systems, stabilization of insulin in presence of hydrophobic components of a microemulsion appears as the most promising strategy. The present paper reports the use of egg yolk for stabilization of insulin in self microemulsifying dispersions. Insulin loaded egg yolk self microemulsifying dispersions were prepared by lyophilization followed by dispersion into self microemulsifying vehicle. The physicochemical characterization of selfmicroemulsifying dispersions includes such as insulin encapsulation efficiency, in vitro stability of insulin in presence of proteolytic enzymes and in vitro release. The biological activity of insulin from the dispersion was estimated by enzyme-linked immunosorbant assay and in vivo using Wistar diabetic rats. The particle size ranged 1.023±0.316 μm in diameter and insulin encapsulation efficiency was 98.2±0.9 %. Insulin hydrophobic self microemulsifying dispersions suppressed insulin release in pH 7.4 phosphate buffer and shown to protect insulin from enzymatic degradation in vitro in presence of chymotripsin. Egg yolk encapsulated insulin was bioactive, demonstrated through both in vivo and in vitro.

Paclitaxel loaded folic acid targeted nanoparticles of mixed lipid-shell and polymer-core: in vitro and in vivo evaluation.

PubMed

Zhao, Peiqi; Wang, Hanjie; Yu, Man; Liao, Zhenyu; Wang, Xianhuo; Zhang, Fei; Ji, Wei; Wu, Bing; Han, Jinghua; Zhang, Haichang; Wang, Huaqing; Chang, Jin; Niu, Ruifang

2012-06-01

A functional drug carrier comprised of folic acid modified lipid-shell and polymer-core nanoparticles (FLPNPs) including poly(D,L-lactide-co-glycolide) (PLGA) core, PEGylated octadecyl-quaternized lysine modified chitosan (PEG-OQLCS) as lipid-shell, folic acid as targeting ligand and cholesterol was prepared and evaluated for targeted delivery of paclitaxel (PTX). Confocal microscopy analysis confirmed the coating of the lipid-shell on the polymer-core. Physicochemical characterizations of FLPNPs, such as particle size, zeta potential, morphology, encapsulation efficiency, and in vitro PTX release, were also evaluated. The internalization efficiency and targeting ability of FLPNPs were demonstrated by flow cytometry and confocal microscopy. PTX loaded FLPNPs showed a significantly higher cytotoxicity than the commercial PTX formulation (Taxol®). The intravenous administration of PTX encapsulated FLPNPs led to tumor regression and improvement of animal survival in a murine model, compared with that observed with Taxol® and biodistribution study showed that PTX concentration in tumor for PTX encapsulated FLPNPs was higher than other PTX formulations. Our data indicate that PTX loaded FLPNPs are a promising nano-sized drug formulation for cancer therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

Dorzolamide Loaded Niosomal Vesicles: Comparison of Passive and Remote Loading Methods.

PubMed

Hashemi Dehaghi, Mohadeseh; Haeri, Azadeh; Keshvari, Hamid; Abbasian, Zahra; Dadashzadeh, Simin

2017-01-01

Glaucoma is a common progressive eye disorder and the treatment strategies will benefit from nanoparticulate delivery systems with high drug loading and sustained delivery of intraocular pressure lowering agents. Niosomes have been reported as a novel approach to improve drug low corneal penetration and bioavailability characteristics. Along with this, poor entrapment efficiency of hydrophilic drug in niosomal formulation remains as a major formulation challenge. Taking this perspective into consideration, dorzolamide niosomes were prepared employing two different loading methodologies (passive and remote loading methods) and the effects of various formulation variables (lipid to drug ratio, cholesterol percentage, drug concentration, freeze/thaw cycles, TPGS content, and external and internal buffer molarity and pH) on encapsulation efficiency were assessed. Encapsulation of dorzolamide within niosomes increased remarkably by the incorporation of higher cholesterol percentage as well as increasing the total lipid concentration. Remote loading method showed higher efficacy for drug entrapment compared to passive loading technique. Incorporation of TPGS in bilayer led to decrease in EE; however, retarded drug release rate. Scanning electron microscopy (SEM) studies confirmed homogeneous particle distribution, and spherical shape with smooth surface. In conclusion, the highest encapsulation can be obtained using phosphate gradient method and 50% cholesterol in Span 60 niosomal formulation.

Development and characterization of phosphatidylcholine nanovesicles, containing garlic extract, with antilisterial activity in milk.

PubMed

Pinilla, Cristian Mauricio Barreto; Noreña, Caciano Pelayo Zapata; Brandelli, Adriano

2017-04-01

Phospholipid nanovesicles were developed to improve the stability of garlic (Allium sativum L.) extract. Electron microscopy of liposomes revealed nanometric and spherical-shaped vesicles with a mean particle size of 174.6±17.3nm and polydispersity index of 0.26±0.02. The entrapment efficiency was 47.5±7.3% and the nanoliposomes had a zeta potential of -16.2±5.5mV. The antimicrobial activity of free and encapsulated garlic extract was evaluated against different strains of Listeria spp. in milk at 37°C for 24h. For free and encapsulated garlic extracts at 5% concentration, a decrease of 4log cycles in viable cell counts was observed at 10h, against four of the five strains of Listeria spp. tested. The results indicate that liposomes constitute a suitable system for encapsulation of unstable garlic active compounds and the encapsulation of garlic extract proves to be a promising technology for multiple applications, including antimicrobial agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Injectable chitosan microparticles incorporating bone morphogenetic protein-7 for bone tissue regeneration

PubMed Central

Mantripragada, Venkata P.; Jayasuriya, Ambalangodage C.

2014-01-01

This study investigates the influence of the controlled release of bone morphogenetic protein 7 (BMP-7) from cross-linked chitosan microparticles on pre-osteoblasts (OB-6) in vitro. BMP-7 was incorporated into microparticles by encapsulation during the particle preparation and coating after particle preparation. Chitosan microparticles had an average diameter of 700 μm containing ~100 ng of BMP-7. The release study profile indicates that nearly 98% of the BMP-7 coated on the microparticles was released in a period of 18 days while only 36% of the BMP-7 encapsulated in the microparticles was released in the same time period. Cell attachment study indicated that the BMP-7 coated microparticles have many cells adhered on the microparticles in comparison with microparticles without growth factors on day 10. DNA assay indicated a statistical significant increase (p<0.05) in the amount of DNA obtained from BMP-7 encapsulated and coated microparticles in comparison with microparticles without any growth factors. A real time RT-PCR experiment was performed to determine the expression of a few osteoblast specific genes - Dlx5, runx2, osterix, osteopontin, osteocalcin, and bone sialoprotein. The results thus suggest that chitosan microparticles obtained by coacervation method are biocompatible and helps in improving the encapsulation efficiency of BMP-7. Also BMP-7 incorporated in the microparticles is being released in a controlled fashion to support attachment, proliferation and differentiation of pre-osteoblasts, thus acting as a good scaffold for bone tissue regeneration. PMID:24497318

Biodegradable Chitosan Magnetic Nanoparticle Carriers for Sub-Cellular Targeting Delivery of Artesunate for Efficient Treatment of Breast Cancer

NASA Astrophysics Data System (ADS)

Subramanian, Natesan; Abimanyu, Sugumaran; Vinoth, Jeevanesan; Sekar, Ponnusamy Chandra

2010-12-01

Artesunate is a semi-synthetic derivative of artemisinin, the active principle extracted from Artemisia annua. It possesses good anti-proliferative activity and anti-angiogenic activity with very low toxicity to normal healthy cells. The drawback of most cancer drugs is their inability to accumulate selectively in the cancerous cells. So, large quantities of doses have to be administered to get the required therapeutic concentration in the target site and it resulted in many serious side effects due to the exposure of healthy cells to higher concentrations of cytotoxic drugs. The problem may be solved by selectively and quantitatively accumulating the drug at target site using magnetic nanoparticles guided by an externally applied magnetic field. A modest attempt has been made in this present study, the artesunate magnetic nanoparticle was successfully formulated using two forms of chitosan and evaluated for its in-vitro characteristics like surface morphology, particle size and distribution, zeta potential, magnetic susceptibility, encapsulation efficiency, loading capacity and in-vitro drug release. The synthesized magnetite size was 73 nm and the size of developed magnetic nanoparticles of artesunate was in the range of 90 to 575 nm. Acetic acid soluble chitosan at low concentration exhibit highest encapsulation efficiency and drug loading whereas increase in water soluble chitosan concentration increases the encapsulation efficiency and drug loading in formulations. The developed chitosan magnetic nanoparticles of artesunate shows better release characteristics and may be screened for its in-vivo breast cancer activity.

Biocompatible Polyelectrolyte Complex Nanoparticles from Lactoferrin and Pectin as Potential Vehicles for Antioxidative Curcumin.

PubMed

Yan, Jing-Kun; Qiu, Wen-Yi; Wang, Yao-Yao; Wu, Jian-Yong

2017-07-19

Polyelectrolyte complex nanoparticles (PEC NPs) were fabricated via electrostatic interactions between positively charged heat-denatured lactoferrin (LF) particles and negatively charged pectin. The obtained PEC NPs were then utilized as curcumin carriers. PEC NPs were prepared by mixing 1.0 mg/mL solutions of heat-denatured LF and pectin at a mass ratio of 1:1 (w/w) in the absence of NaCl at pH 4.50. PEC NPs that were prepared under optimized conditions were spherical in shape with a particle size of ∼208 nm and zeta potential of ∼-32 mV. Hydrophobic curcumin was successfully encapsulated into LF/pectin PEC NPs with high encapsulation efficiency (∼85.3%) and loading content (∼13.4%). The in vitro controlled release and prominent antioxidant activities of curcumin from LF/pectin PEC NPs were observed. The present work provides a facile and fast method to synthesize nanoscale food-grade delivery systems for the improved water solubility, controlled release, and antioxidant activity of hydrophobic curcumin.

Platinum-coated non-noble metal-noble metal core-shell electrocatalysts

DOEpatents

Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir

2015-04-14

Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.

Preparation of mesoporous silica microparticles by sol-gel/emulsion route for protein release.

PubMed

Vlasenkova, Mariya I; Dolinina, Ekaterina S; Parfenyuk, Elena V

2018-04-06

Encapsulation of therapeutic proteins into particles from appropriate material can improve both stability and delivery of the drugs, and the obtained particles can serve as a platform for development of their new oral formulations. The main goal of this work was development of sol-gel/emulsion method for preparation of silica microcapsules capable of controlled release of encapsulated protein without loss of its native structure. For this purpose, the reported in literature direct sol-gel/W/O/W emulsion method of protein encapsulation was used with some modifications, because the original method did not allow to prepare silica microcapsules capable for protein release. The particles were synthesized using sodium silicate and tetraethoxysilane as silica precursors and different compositions of oil phase. In vitro kinetics of bovine serum albumin (BSA) release in buffer (pH 7.4) was studied by Fourier transform infrared (FTIR) and fluorescence spectrometry, respectively. Structural state of encapsulated BSA and after release was evaluated. It was found that the synthesis conditions influenced substantially the porous structure of the unloaded silica particles, release properties of the BSA-loaded silica particles and structural state of the encapsulated and released protein. The modified synthesis conditions made it possible to obtain the silica particles capable of controlled release of the protein during a week without loss of the protein native structure.

Preparation and characterization of isoniazid-loaded crude soybean lecithin liposomes.

PubMed

Nkanga, Christian Isalomboto; Krause, Rui Werner; Noundou, Xavier Siwe; Walker, Roderick Bryan

2017-06-30

Tuberculosis (TB) is a poverty related infectious disease that is rapidly giving rise to public health concerns. Lengthy drug administration and frequent adverse side-effects associated with TB treatment make anti-tubercular drugs (ATDs) good candidates for drug delivery studies. This work aimed to formulate and prepare liposomes as a cost-effective option for ATD delivery. Liposomes were prepared by film hydration using crude soybean lecithin (CL) and not pure phospholipids as in the normal practice. Cholesterol was also used (up to 25% mass ratio), and isoniazid (INH) was encapsulated as model drug using a freeze-thaw loading technique. Purified soybean lecithin (PL) was also used for comparative purposes, under the same conditions. INH-loaded liposomes were characterized for particle size, Zeta Potential (ZP), encapsulation efficiency (EE) and drug release. Physicochemical properties were investigated using thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared. INH-loaded CL-based liposomes showed high EE (79±2.45%). The average particle size (813.00±9.21nm) and ZP (-42.80±4.31mV) of this formulation are promising for the treatment of TB by pulmonary delivery. These findings suggest the possibility of encapsulating ATDs in liposomes made of crude soybean lecithin that is cheap and readily available. Copyright © 2017 Elsevier B.V. All rights reserved.

Highly selective oxidation of styrene to benzaldehyde over a tailor-made cobalt oxide encapsulated zeolite catalyst.

PubMed

Liu, Jiangyong; Wang, Zihao; Jian, Panming; Jian, Ruiqi

2018-05-01

A tailor-made catalyst with cobalt oxide particles encapsulated into ZSM-5 zeolites (Co 3 O 4 @HZSM-5) was prepared via a hydrothermal method with the conventional impregnated Co 3 O 4 /SiO 2 catalyst as the precursor and Si source. Various characterization results show that the Co 3 O 4 @HZSM-5 catalyst has well-organized structure with Co 3 O 4 particles compatibly encapsulated in the zeolite crystals. The Co 3 O 4 @HZSM-5 catalyst was employed as an efficient catalyst for the selective oxidation of styrene to benzaldehyde with hydrogen peroxide as a green and economic oxidant. The effect of various reaction conditions including reaction time, reaction temperature, different kinds of solvents, styrene/H 2 O 2 molar ratio and catalyst dosage on the catalytic performance were systematically investigated. Under the optimized reaction condition, the yield of benzaldehyde can achieve 78.9% with 96.8% styrene conversion and 81.5% benzaldehyde selectivity. Such an excellent catalytic performance can be attributed to the synergistic effect between the confined reaction environment and the proper acidic property. In addition, the reaction mechanism with Co 3 O 4 @HZSM-5 as the catalyst for the selective oxidation of styrene to benzaldehyde was reasonably proposed. Copyright © 2018 Elsevier Inc. All rights reserved.

Development of Metronidazole-Loaded Colon-Targeted Microparticulate Drug Delivery System.

PubMed

Kumar, Manoj; Awasthi, Rajendra

2015-01-01

Crohn’s disease and ulcerative colitis are the main autoimmune inflammatory bowel diseases. Metronidazole is the most commonly used drug for the treatment of Crohn’s disease. However, the pharmacokinetic profile of this drug indicates that the largest amount of the drug is absorbed from the upper part of the intestines and very little concentration of the drugs reaches the colon.Objectives: The aim of this investigation was to formulate metronidazole loaded microspheres for the efficient therapy of inflammatory bowel diseases.Material and Methods: Microspheres were prepared using the emulsification-solvent evaporation method. The effect of Eudragit S100 concentration and the ratio of liquid paraffin (light: heavy) on percentage yield, particle size, morphology, drug encapsulation and in vitro drug release was examined. Drug-polymer interaction was investigated using Fourier Transformed Infrared Spectroscopy (FTIR). The results showed that the particle had good flow properties, encapsulation efficiency (56.11 ・} 1.51–81.02 ・} 2.14%)and cumulative drug release (64.14 ・} 0.83–79.69 ・} 2.45%) in a phosphate buffer (pH 6.8) after 10 h of the dissolution study.An increased particle size was observed with an increasing polymer concentration. It was observed that the Eudragit had a positive effect on the drug encapsulation and negative effect on drug release. Aggregation of drug-polymer droplets was observed at a lower level of magnesium stearate during microsphere preparation. The results of FTIR spectroscopy revealed the absence of any drug-polymer interactions. However, slight peak shifting and suppression in peak height was observed.This might be due to the minor ionic interactions. The microspheres were discrete, spherical and free-flowing. The spherical shape of the microspheres was confirmed from SEM photomicrographs. The developed microspheres showed a controlled drug release and were found to follow Higuchi’s model. The release mechanism of metronidazole from the microspheres was Fickian diffusion without swelling. The results suggest that the developed microspheres could enhance drug entrapment, and inflect the drug release.

Self-assembled virus-like particles with magnetic cores.

PubMed

Huang, Xinlei; Bronstein, Lyudmila M; Retrum, John; Dufort, Chris; Tsvetkova, Irina; Aniagyei, Stella; Stein, Barry; Stucky, Galen; McKenna, Brandon; Remmes, Nicholas; Baxter, David; Kao, C Cheng; Dragnea, Bogdan

2007-08-01

Efficient encapsulation of functionalized spherical nanoparticles by viral protein cages was found to occur even if the nanoparticle is larger than the inner cavity of the native capsid. This result raises the intriguing possibility of reprogramming the self-assembly of viral structural proteins. The iron oxide nanotemplates used in this work are superparamagnetic, with a blocking temperature of about 250 K, making these virus-like particles interesting for applications such as magnetic resonance imaging and biomagnetic materials. Another novel feature of the virus-like particle assembly described in this work is the use of an anionic lipid micelle coat instead of a molecular layer covalently bound to the inorganic nanotemplate. Differences between the two functionalization strategies are discussed.

Preparation and in vitro evaluation of simvastatin ethosome.

PubMed

An, Keyao; Sun, Yong; Xu, Lisa; Cui, Xiangzhen

2011-12-01

To prepare ethosome loading simvastatin,an orthogonal test was applied to optimize the prescriptions, and the qualities of simvastatin ethosome were characterized by the shape, particle size, encapsulation efficiency (EE), and stability. The formation of 40% (v/v) ethanol, 0.02% (m/v) cholesterol, 2.0% (m/v) soy lecithin, and 5% (m/v) polyoxyethylene hydrogenated castor oil showed the maximal EE (69.3%). We observed the shape of simvastatin ethosome through TEM. The average size of the particles was 52.4 ± 3.24 nm, which was detected by a N5 submicron particle size analyzer. After 120 days storage in 4? and at room temperature, the simvastatin ethosome had no significant change.

Novel Transparent Phosphor Conversion Matrix with High Thermal Conductivity for Next Generation Phosphor-Converted LED-based Solid State Lighting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bockstaller, Michael

The low thermal conductivity of state-of-the-art polymer encapsulants (k ~ 0.15 Wm-1K-1) limits the efficiency and power density of current phosphor conversion light emitting diodes (pc-LEDs). The technical objective of this project was to demonstrate synthesis and processing schemes for the fabrication of polymer hybrid encapsulants with a thermal conductivity exceeding k = 0.4 Wm-1K-1 for LED applications. The ‘hybrid polymer’ approach encompasses the dispersion of high thermal conductivity particle fillers (zinc oxide, ZnO as well as the alpha-polymorph of alumina, Al2O3) within a polysiloxane matrix (poly(dimethylsiloxane), PDMS as well as poly(phenyl methyl siloxane), PPMS) to increase the thermal conductivitymore » while maintaining optical transparency and photothermal stability at levels consistent with LED applications. To accomplish this goal, a novel synthesis method for the fabrication of nanosized ZnO particles was developed and a novel surface chemistry was established to modify the surface of zinc oxide particle fillers and thus to enable their dispersion in poly(dimethyl siloxane) (PDMS) matrix polymers. Molecular dynamics and Mie simulations were used to optimize ligand structure and to enable the concurrent mixing of particles in PDMS/PPMS embedding media while also minimizing the thermal boundary resistance as well as optical scattering of particle fillers. Using this approach the synthesis of PDMS/ZnO hybrid encapsulants exhibiting a thermal conductivity of 0.64 Wm-1K-1 and optical transparency > 0.7 mm-1 was demonstrated. A forming process based on micromolding was developed to demonstrate the forming of particle filled PDMS into film and lens shapes. Photothermal stability testing revealed stability of the materials for approximately 4000 min when exposed to blue light LED (450 nm, 30 W/cm2). One postgraduate and seven graduate students were supported by the project. The research performed within this project led to fifteen publications in peer-reviewed journals and one patent application. The grant stimulated a multi-investigator research collaborations among seven investigators at Carnegie Mellon University to address the challenge of encapsulants in pc-LED applications. The grant also catalyzed the future collaboration between researchers at Carnegie Mellon University and OSRAM Sylvania to address challenges associated with the use if polymers in LED applications.« less

Effects of Formulation Variables on the Particle Size and Drug Encapsulation of Imatinib-Loaded Solid Lipid Nanoparticles.

PubMed

Gupta, Biki; Poudel, Bijay Kumar; Pathak, Shiva; Tak, Jin Wook; Lee, Hee Hyun; Jeong, Jee-Heon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

2016-06-01

Imatinib (IMT), an anticancer agent, inhibits receptor tyrosine kinases and is characterized by poor aqueous solubility, extensive first-pass metabolism, and rapid clearance. The aims of the current study are to prepare imatinib-loaded solid lipid nanoparticles (IMT-SLN) and study the effects of associated formulation variables on particle size and drug encapsulation on IMT-SLN using an experimental design. IMT-SLN was optimized by use of a "combo" approach involving Plackett-Burman design (PBD) and Box-Behnken design (BBD). PBD screening resulted in the determination of organic-to-aqueous phase ratio (O/A), drug-to-lipid ratio (D/L), and amount of Tween® 20 (Tw20) as three significant variables for particle size (S z), drug loading (DL), and encapsulation efficiency (EE) of IMT-SLN, which were used for optimization by BBD, yielding an optimized criteria of O/A = 0.04, D/L = 0.03, and Tw20 = 2.50% w/v. The optimized IMT-SLN exhibited monodispersed particles with a size range of 69.0 ± 0.9 nm, ζ-potential of -24.2 ± 1.2 mV, and DL and EE of 2.9 ± 0.1 and 97.6 ± 0.1% w/w, respectively. Results of in vitro release study showed a sustained release pattern, presumably by diffusion and erosion, with a higher release rate at pH 5.0, compared to pH 7.4. In conclusion, use of the combo experimental design approach enabled clear understanding of the effects of various formulation variables on IMT-SLN and aided in the preparation of a system which exhibited desirable physicochemical and release characteristics.

Deformable microparticles with multiple functions for drug delivery and device testing

NASA Astrophysics Data System (ADS)

Thula, Taili T.

Since the HIV epidemic of the 1990s, researchers have attempted to develop a red blood cell analog. Even though some of these substitutes are now in Phase III of clinical trials, their use is limited by side effects and short half-life in the human body. As a result, there is still a need for an effective erythrocyte analog with minimum immunogenic and side effects, so that it can be used for multiple applications. Finding new approaches to develop more efficient blood substitutes will not only bring valuable advances in the clinical approach, but also in the area of in vitro testing of medical devices. We examined the feasibility of creating a deformable multi-functional, biodegradable, biocompatible particle for applications in drug delivery and device testing. As a preliminary evaluation, we synthesized different types of microcapsules using natural and synthetic polymers, various cross-linking agents, and diverse manufacturing techniques. After fully characterizing of each system, we determined the most promising red blood cell analog in terms of deformability, stability and toxicity. We also examined the encapsulation and release of bovine serum albumin (BSA) within these deformable particles. After removal of cross-linkers, zinc- and copper-alginate microparticles surrounded by multiple polyelectrolyte layers of chitosan oligosaccharide and alginate were deformable and remained stable under physiological pressures applied by the micropipette technique. In addition, multiple coatings decreased toxicity of heavy-metal crosslinked particles. BSA encapsulation and release from chitosan-alginate microspheres were contingent on the crosslinker and number of polyelectrolyte coatings, respectively. Further rheological studies are needed to determine how closely these particles simulate the behavior of erythrocytes. Also, studies on the encapsulation and release of different proteins, including hemoglobin, are needed to establish the desired controlled release of bioactive agents for the proposed delivery system.

Study of Structural and Magnetic Properties of Silica and Polyethylene Glycol (PEG-4000)-Encapsulated Magnesium Nickel Ferrite (Mg0.5Ni0.5Fe2O4) Nanoparticles

NASA Astrophysics Data System (ADS)

Deswardani, F.; Maulia, R.; Suharyadi, E.

2017-05-01

Mg0.5Ni0.5Fe2O4 has been successfully synthesized by using co-precipitation method. Two series of Mg0.5Ni0.5Fe2O4 silica encapsulated have been prepared by varying the concentration of silica and variation of PEG-4000 concentration. Analysis of X-Ray Diffraction (XRD) pattern showed that nanoparticles contained Mg0.5Ni0.5Fe2O4 spinel phase and γ-Fe2O3 phase with a particle size of 5.1 nm. The various of silica encapsulation give rise to produce a new phase of SiO2 and increase the particle size to 16.1 nm. PEG-4000 encapsulation affected to create a new phase of γ-FeO(OH), and reduce the particle size down to 4.5 nm. Fourier Transform Infra Red (FTIR) for Mg0.5Ni0.5Fe2O4 showed absorption peaks around 300-600 cm-1 which are M-O bond vibration. After silica encapsulation, there was new bond vibration typical of silica such as Si-O-Si (1049.28 cm-1), Si-OH (779.24 cm-1), and Si-O-Fe (570.93 cm-1). The PEG-4000 encapsulation creates a new vibration for typical of PEG-like of C-O (1103.28 cm-1) and C-H (925.83, 1481.33, and 2924.09 cm-1). Both of encapsulations series have M-O bond vibration indicating the presence of Mg0.5Ni0.5Fe2O4. After silica encapsulation, the coercivity of Mg0.5Ni0.5Fe2O4 decreased from 47 Oe to 10 Oe due to the decrease of particle size. Even though, the discrepancy of particle size as the effect of PEG-4000 encapsulation, the coercivity just slightly reduced to 46 Oe. The saturation magnetization of Mg0.5Ni0.5Fe2O4 decreased from 4.7 emu/g to 1 emu/g after silica encapsulation because diamagnetic SiO2. Otherwise, the saturation magnetization increased to 7.7 emu/g after PEG-4000 encapsulation because of domination of Mg0.5Ni0.5Fe2O4 phase ratio.

Brain targeted oral delivery of doxycycline hydrochloride encapsulated Tween 80 coated chitosan nanoparticles against ketamine induced psychosis: behavioral, biochemical, neurochemical and histological alterations in mice.

PubMed

Yadav, Monu; Parle, Milind; Sharma, Nidhi; Dhingra, Sameer; Raina, Neha; Jindal, Deepak Kumar

2017-11-01

To develop statistically optimized brain targeted Tween 80 coated chitosan nanoparticulate formulation for oral delivery of doxycycline hydrochloride for the treatment of psychosis and to evaluate its protective effect on ketamine induced behavioral, biochemical, neurochemical and histological alterations in mice. 3 2 full factorial design was used to optimize the nanoparticulate formulation to minimize particle size and maximize entrapment efficiency, while independent variables chosen were concentration of chitosan and Tween 80. The optimized formulation was characterized by particle size, drug entrapment efficiency, Fourier transform infrared, Transmission electron microscopy analysis and drug release behavior. Pure doxycycline hydrochloride (25 and 50 mg/kg, p.o.) and optimized doxycycline hydrochloride encapsulated Tween 80 coated chitosan nanoparticles (DCNP opt ) (equivalent to 25 mg/kg doxycycline hydrochloride, p.o.) were explored against ketamine induced psychosis in mice. The experimental studies for DCNP opt , with mean particle size 237 nm and entrapment efficiency 78.16%, elucidated that the formulation successfully passed through blood brain barrier and exhibited significant antipsychotic activity. The underlying mechanism of action was further confirmed by behavioral, biochemical, neurochemical estimations and histopathological study. Significantly enhanced GABA and GSH level and diminished MDA, TNF-α and dopamine levels were observed after administration of DCNP opt at just half the dose of pure doxycycline hydrochloride, showing better penetration of doxycyline hydrochloride in the form of Tween 80 coated nanoparticles through blood brain barrier. This study demonstrates the hydrophilic drug doxycycline hydrochloride, loaded in Tween 80 coated chitosan nanoparticles, can be effectively brain targeted through oral delivery and therefore represents a suitable approach for the treatment of psychotic symptoms.

Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo.

PubMed

Gou, MaLing; Men, Ke; Shi, HuaShan; Xiang, MingLi; Zhang, Juan; Song, Jia; Long, JianLin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, ZhiYong

2011-04-01

Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 ± 0.011) with a mean particle size of 27.3 ± 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 ± 1.02%, and drug loading of 12.95 ± 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t(1/2) and AUC of curcumin in vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesis in vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cells in vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg(-1) curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

Transferrin liposomes of docetaxel for brain-targeted cancer applications: formulation and brain theranostics.

PubMed

Sonali; Singh, Rahul Pratap; Singh, Nitesh; Sharma, Gunjan; Vijayakumar, Mahalingam R; Koch, Biplob; Singh, Sanjay; Singh, Usha; Dash, Debabrata; Pandey, Bajarangprasad L; Muthu, Madaswamy S

2016-05-01

Diagnosis and therapy of brain cancer was often limited due to low permeability of delivery materials across the blood-brain barrier (BBB) and their poor penetration into the brain tissue. This study explored the possibility of utilizing theranostic d-alpha-tocopheryl polyethylene glycol 1000 succinate mono-ester (TPGS) liposomes as nanocarriers for minimally invasive brain-targeted imaging and therapy (brain theranostics). The aim of this work was to formulate transferrin conjugated TPGS coated theranostic liposomes, which contain both docetaxel and quantum dots (QDs) for imaging and therapy of brain cancer. The theranostic liposomes with and without transferrin decoration were prepared and characterized for their particle size, polydispersity, morphology, drug encapsulation efficiency, in-vitro release study and brain theranostics. The particle sizes of the non-targeted and targeted theranostic liposomes were found below 200 nm. Nearly, 71% of drug encapsulation efficiency was achieved with liposomes. The drug release from transferrin conjugated theranostic liposomes was sustained for more than 72 h with 70% of drug release. The in-vivo results indicated that transferrin receptor-targeted theranostic liposomes could be a promising carrier for brain theranostics due to nano-sized delivery and its permeability which provided an improved and prolonged brain targeting of docetaxel and QDs in comparison to the non-targeted preparations.

Effect of polymer architecture on curcumin encapsulation and release from PEGylated polymer nanoparticles: Toward a drug delivery nano-platform to the CNS.

PubMed

Rabanel, Jean-Michel; Faivre, Jimmy; Paka, Ghislain Djiokeng; Ramassamy, Charles; Hildgen, Patrice; Banquy, Xavier

2015-10-01

We developed a nanoparticles (NPs) library from poly(ethylene glycol)-poly lactic acid comb-like polymers with variable amount of PEG. Curcumin was encapsulated in the NPs with a view to develop a delivery platform to treat diseases involving oxidative stress affecting the CNS. We observed a sharp decrease in size between 15 and 20% w/w of PEG which corresponds to a transition from a large solid particle structure to a "micelle-like" or "polymer nano-aggregate" structure. Drug loading, loading efficacy and release kinetics were determined. The diffusion coefficients of curcumin in NPs were determined using a mathematical modeling. The higher diffusion was observed for solid particles compared to "polymer nano-aggregate" particles. NPs did not present any significant toxicity when tested in vitro on a neuronal cell line. Moreover, the ability of NPs carrying curcumin to prevent oxidative stress was evidenced and linked to polymer architecture and NPs organization. Our study showed the intimate relationship between the polymer architecture and the biophysical properties of the resulting NPs and sheds light on new approaches to design efficient NP-based drug carriers. Copyright © 2015 Elsevier B.V. All rights reserved.

Monte Carlo Simulation of Nanoparticle Encapsulation in Flames

NASA Technical Reports Server (NTRS)

Sun, Z.; Huertas, J. I.; Axelbaum, R. L.

1999-01-01

Two critical challenges facing the application of flames for synthesis of nanopowder materials are: (1) overcoming formation of agglomerates and (2) ensuring that the highly reactive nanopowders that are synthesized in flames can be produced in such a manner that their purity is maintained during subsequent processing. Agglomerates are produced in flames because particle formation occurs in a high temperature and high number density environment. They are undesirable in most advanced applications of powders. For example, agglomerates have a deleterious effect on compaction density, leading to voids when nanopowders are consolidated. Efforts to avoid agglomeration in flames without substantially reducing particle number density and, consequently, production rate, have had limited success. Powder purity must also be maintained during subsequent handling of nanopowders and this poses a significant challenge for any synthesis route because nanopowders, particularly metals and non-oxide ceramic powders, are inherently reactive. Impurities acquired during handling of nanopowders have slowed the advancement of the nanostructured materials industry. One promising approach that has been proposed to address these problems is nano-encapsulation. In this approach, the core particles are encapsulated in a removable material while they are within the flame but before excessive agglomeration has occurred. Condensation can be very rapid so that core particles are trapped within the condensed material and agglomeration is limited. Nano-encapsulation also addresses the handling concerns for post-synthesis processing. Results have shown that when nano-encapsulated powders are exposed to atmosphere the core particles are protected from oxidation and/or hydrolysis. Thus, handling of the powders does not require extreme care. If, for example, at the time of consolidation the encapsulation material is removed by vacuum annealing, the resulting powder remains unagglomerated and free of impurities. In this work, we described a novel aerosol model that has been developed to simulate particle encapsulation in flames. The model will ultimately be coupled to a one-dimensional spherical flame code and compared to results from microgravity flame experiments.

Nano spray drying for encapsulation of pharmaceuticals.

PubMed

Arpagaus, Cordin; Collenberg, Andreas; Rütti, David; Assadpour, Elham; Jafari, Seid Mahdi

2018-05-17

Many pharmaceuticals such as pills, capsules, or tablets are prepared in a dried and powdered form. In this field, spray drying plays a critical role to convert liquid pharmaceutical formulations into powders. In addition, in many cases it is necessary to encapsulate bioactive drugs into wall materials to protect them against harsh process and environmental conditions, as well as to deliver the drug to the right place and at the correct time within the body. Thus, spray drying is a common process used for encapsulation of pharmaceuticals. In view of the rapid progress of nanoencapsulation techniques in pharmaceutics, nano spray drying is used to improve drug formulation and delivery. The nano spray dryer developed in the recent years provides ultrafine powders at nanoscale and high product yields. In this paper, after explaining the concept of nano spray drying and understanding the key elements of the equipment, the influence of the process parameters on the final powders properties, like particle size, morphology, encapsulation efficiency, drug loading and release, will be discussed. Then, numerous application examples are reviewed for nano spray drying and encapsulation of various drugs in the early stages of product development along with a brief overview of the obtained results and characterization techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

[Preparation of Oenothera biennis Oil Solid Lipid Nanoparticles Based on Microemulsion Technique].

PubMed

Piao, Lin-mei; Jin, Yong; Cui, Yan-lin; Yin, Shou-yu

2015-06-01

To study the preparation of Oenothera biennis oil solid lipid nanoparticles and its quality evaluation. The solid lipid nanoparticles were prepared by microemulsion technique. The optimum condition was performed based on the orthogonal design to examine the entrapment efficiency, the mean diameter of the particles and so on. The optimal preparation of Oenothera biennis oil solid lipid nanoparticles was as follows: Oenothera biennis dosage 300 mg, glycerol monostearate-Oenothera biennis (2: 3), Oenothera biennis -RH/40/PEG-400 (1: 2), RH-40/PEG-400 (1: 2). The resulting nanoparticles average encapsulation efficiency was (89.89 ± 0.71)%, the average particle size was 44.43 ± 0.08 nm, and the Zeta potential was 64.72 ± 1.24 mV. The preparation process is simple, stable and feasible.

Encapsulation of albumin in self-assembled layer-by-layer microcapsules: comparison of co-precipitation and adsorption techniques.

PubMed

Labala, Suman; Mandapalli, Praveen Kumar; Bhatnagar, Shubhmita; Venuganti, Venkata Vamsi Krishna

2015-01-01

The objective of this study is to prepare and characterize polymeric self-assembled layer-by-layer microcapsules (LbL-MC) to deliver a model protein, bovine serum albumin (BSA). The aim is to compare the BSA encapsulation in LbL-MC using co-precipitation and adsorption methods. In co-precipitation method, BSA was co-precipitated with growing calcium carbonate particles to form a core template. Later, poly(styrene sulfonate) and poly(allylamine hydrochloride) were sequentially adsorbed onto the CaCO3 templates. In adsorption method, preformed LbL-MC were incubated with BSA and encapsulation efficiency is optimized for pH and salt concentration. Free and BSA-encapsulated LbL-MC were characterized using Zetasizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimeter. Later, in vitro release studies were performed using dialysis membrane method at pH 4, 7.4 and 9. Results from Zetasizer and SEM showed free LbL-MC with an average size and zeta-potential of 2.0 ± 0.6 μm and 8.1 ± 1.9 mV, respectively. Zeta-potential of BSA-loaded LbL-MC was (-)7.4 ± 0.7 mV and (-)5.7 ± 1.0 mV for co-precipitation and adsorption methods, respectively. In adsorption method, BSA encapsulation in LbL-MC was found to be greater at pH 6.0 and 0.2 M NaCl. Co-precipitation method provided four-fold greater encapsulation efficiency (%) of BSA in LbL-MC compared with adsorption method. At pH 4, the BSA release from LbL-MC was extended up to 120 h. Polyacrylamide gel electrophoresis showed that BSA encapsulated in LBL-MC through co-precipitation is stable toward trypsin treatment. In conclusion, co-precipitation method provided greater encapsulation of BSA in LbL-MC. Furthermore, LbL-MC can be developed as carriers for pH-controlled protein delivery.

Treating acute cystitis with biodegradable micelle-encapsulated quercetin

PubMed Central

Wang, Bi Lan; Gao, Xiang; Men, Ke; Qiu, Jinfeng; Yang, Bowen; Gou, Ma Ling; Huang, Mei Juan; Huang, Ning; Qian, Zhi Yong; Zhao, Xia; Wei, Yu Quan

2012-01-01

Intravesical application of an anti-inflammatory drug is an efficient strategy for acute cystitis therapy. Quercetin (QU) is a potent anti-inflammatory agent; however, its poor water solubility restricts its clinical application. In an attempt to improve water solubility of QU, biodegradable monomethoxy poly(ethylene glycol)-poly(ɛ-caprolactone) (MPEG-PCL) micelles were used to encapsulate QU by self-assembly methods, creating QU/MPEG-PCL micelles. These QU/MPEG-PCL micelles with DL of 7% had a mean particle size of <34 nm, and could release QU for an extended period in vitro. The in vivo study indicated that intravesical application of MPEG-PCL micelles did not induce any toxicity to the bladder, and could efficiently deliver cargo to the bladder. Moreover, the therapeutic efficiency of intravesical administration of QU/MPEG-PCL micelles on acute cystitis was evaluated in vivo. Results indicated that QU/MPEG-PCL micelle treatment efficiently reduced the edema and inflammatory cell infiltration of the bladder in an Escherichia coli-induced acute cystitis model. These data suggested that MPEG-PCL micelle was a candidate intravesical drug carrier, and QU/MPEG-PCL micelles may have potential application in acute cystitis therapy. PMID:22661886

Preparation and characterization of essential oil-loaded starch nanoparticles formed by short glucan chains.

PubMed

Qiu, Chao; Chang, Ranran; Yang, Jie; Ge, Shengju; Xiong, Liu; Zhao, Mei; Li, Man; Sun, Qingjie

2017-04-15

Essential oils (EOs), including menthone, oregano, cinnamon, lavender, and citral, are natural products that have antimicrobial and antioxidant activities. However, extremely low water solubility, and easy degradation by heat, restrict their application. The aim of this work was to evaluate the enhancement in antioxidative and antimicrobial activities of EOs encapsulated in starch nanoparticles (SNPs) prepared by short glucan chains. For the first time, we have successfully fabricated menthone-loaded SNPs (SNPs-M) at different complexation temperatures (30, 60, and 90°C) by an in situ nanoprecipitation method. The SNPs-M displayed spherical shapes, and the particle sizes ranged from 93 to 113nm. The encapsulation efficiency (EE) of SNPs-M increased significantly with an increase in complexation temperature, and the maximum EE was 86.6%. The SNPs-M formed at 90°C had high crystallization and thermal stability. The durations of the antioxidant and antimicrobial activities of EOs was extended by their encapsulation in the SNPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nano-preparation of Andrographis paniculata extract by casein micelle for antidiabetic agent

NASA Astrophysics Data System (ADS)

Arbianti, Rita; Dewi, Veronica; Imansari, Farisa; Hermansyah, Heri; Sahlan, Muhamad

2017-02-01

Side effects caused by oral medications for person with diabetic are the background of the development of alternative treatments by traditional medicine, herbs. Andrographis paniculata (AP) is one of the herbs that is potent to be anti-diabetic agent. The active compound of AP, andrographolide have been examined to have anti-diabetic activity as α-glucosidase enzyme inhibitor. This research aims to encapsulate sambiloto's extract with casein micelle and produce nanoparticles which have anti-diabetic activity as α-glucosidase inhibitor. Extract of AP is encapsulated by casein micelle and made into nano size using sonicator. The dominant active compounds in AP extract coated by casein are andrographolide, neoandrographolide, 14-deoxy-11,12didehydroandrographolide with encapsulation efficiency of 68.83%, 89.15% and 81.69%, the average diameter of the particles is about 120.57 nm and its loading capacity is 28.85%. AP's extract has antidiabetic activity as α-glucosidase inhibitor with percent inhibition of 95%. The morphology of nanoencapsulated AP's extract analyzed by FE-SEM, were similar with casein micelle.

Formulation of Nanoliposomal Vitamin D3 for Potential Application in Beverage Fortification

PubMed Central

Mohammadi, Maryam; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2014-01-01

Purpose: Vitamin D, a liposoluble vitamin has many benefits on health. Encapsulation of bioactives in lipid-based carrier systems like nanoliposomes preserves their native properties against oxidation over time along with providing its stable aqueous dispersion. Methods: In the current study, vitamin D3 nanoliposomes were prepared using thin-film hydration-sonication method and fully characterized by different instrumental techniques. Results: According to FTIR and DSC results, no interaction was observed between encapsulated nutraceutical and liposome constituents. The particle size and size distribution (Span value) were calculated 82–90 nm and 0.70–0.85, respectively. TEM analysis showed nano sized globular and bilayer vesicles. In all formations, the encapsulation efficiency of vitamin D3 was calculated more than 93%. Addition of cholesterol to lecithin bilayer increased the negative zeta potential from -29 to -43mV. Conclusion: The results of this study concluded that the liposomal nanoparticles may be introduced as a suitable carrier for fortification of beverages with vitamin D3. PMID:25671191

Doxycycline delivery from PLGA microspheres prepared by a modified solvent removal method.

PubMed

Patel, Roshni S; Cho, Daniel Y; Tian, Cheng; Chang, Amy; Estrellas, Kenneth M; Lavin, Danya; Furtado, Stacia; Mathiowitz, Edith

2012-01-01

We report on the development of a modified solvent removal method for the encapsulation of hydrophilic drugs within poly(lactic-co-glycolic acid) (PLGA). Using a water/oil/oil double emulsion, hydrophilic doxycycline was encapsulated within PLGA spheres with particle diameters ranging from approximately 600 nm to 19 µm. Encapsulation efficiencies of up to 74% were achieved for theoretical loadings from 1% to 10% (w/w), with biphasic release over 85 days with nearly complete release at the end of this time course. About 1% salt was added to the formulations to examine its effects on doxycycline release; salt modulated release only by increasing the magnitude of initial release without altering kinetics. Fourier transform infrared spectroscopy indicated no characteristic differences between doxycycline-loaded and control spheres. Differential scanning calorimetry and X-ray diffraction suggest that there may be a molecular dispersion of the doxycycline within the spheres and the doxycycline may be in an amorphous state, which could explain the slow, prolonged release of the drug.

Encapsulation and release studies of strawberry polyphenols in biodegradable chitosan nanoformulation.

PubMed

Pulicharla, Rama; Marques, Caroline; Das, Ratul Kumar; Rouissi, Tarek; Brar, Satinder Kaur

2016-07-01

Polyphenols (negative groups) of strawberry extract interacts with positively protonated amino groups of chitosan which helps in maximum encapsulation. This approach can improve the bioavailability and sustained release of phytochemicals having lower bioavailability. The optimum mass ratio of chitosan-tripolyphosphate and polyphenols (PPs) loading was investigated to be 3:1 and 0.5mg/ml of strawberry extract, respectively. Prepared nanoformulation were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The formed particles size ranged between 300 and 600nm and polydispersity index (PDI) of≈0.5. The optimized formulation showed encapsulation efficiency of 58.09% at 36.47% of polyphenols loading. Initial burst and continuous release of PPs was observed at pH 7.4 of in vitro release studies. PPs release profile at this pH was found to be non-Fickian analomous diffusion and the release was followed first order kinetics. And at pH 1.4, diffusion-controlled Fickian release of PPs was observed. Copyright © 2016 Elsevier B.V. All rights reserved.

A study of properties of "micelle-enhanced" polyelectrolyte capsules: Structure, encapsulation and in vitro release.

PubMed

Li, Xiaodong; Lu, Tian; Zhang, Jianxiang; Xu, Jiajie; Hu, Qiaoling; Zhao, Shifang; Shen, Jiacong

2009-07-01

"Micelle-enhanced" polyelectrolyte capsules were fabricated via a layer-by-layer technique, templated on hybrid calcium carbonate particles with built-in polymeric micelles based on polystyrene-b-poly(acrylic acid). Due to the presence of a large number of negatively charged micelles inside the polyelectrolyte capsule, which were liberated from templates, the capsule wall was reconstructed and had properties different to those of conventional polyelectrolyte capsules. This type of capsule could selectively entrap positively charged water-soluble substances. The encapsulation efficiency of positively charged substances was dependent on their molecular weight or size. For some positively charged compounds, such as rhodamine B and lysozyme, the concentration in the capsules was orders of magnitude higher than that in the incubation solution. In addition, in vitro release study suggested that the encapsulated compounds could be released through a sustained manner to a certain degree. All these results point to the fact that these capsules might be used as novel delivery systems for some water-soluble compounds.

Fabrication, characterization and antimicrobial activities of thymol-loaded zein nanoparticles stabilized by sodium caseinate-chitosan hydrochloride double layers.

PubMed

Zhang, Yaqiong; Niu, Yuge; Luo, Yangchao; Ge, Mei; Yang, Tian; Yu, Liangli Lucy; Wang, Qin

2014-01-01

Thymol-loaded zein nanoparticles stabilized with sodium caseinate (SC) and chitosan hydrochloride (CHC) were prepared and characterized. The SC stabilized nanoparticles had well-defined size range and negatively charged surface. Due to the presence of SC, the stabilized zein nanoparticles showed a shift of isoelectric point from 6.18 to 5.05, and had a desirable redispersibility in water at neutral pH after lyophilization. Coating with CHC onto the SC stabilized zein nanoparticles resulted in increased particle size, reversal of zeta potential value from negative to positive, and improved encapsulation efficiency. Both thymol-loaded zein nanoparticles and SC stabilized zein nanoparticles had a spherical shape and smooth surface, while the surfaces of CHC-SC stabilized zein nanoparticles seemed rough and had some clumps. Encapsulated thymol was more effective in suppressing gram-positive bacterium than un-encapsulated thymol for a longer time period. Copyright © 2013 Elsevier Ltd. All rights reserved.

New trends in encapsulation of liposoluble vitamins.

PubMed

Gonnet, M; Lethuaut, L; Boury, F

2010-09-15

Liposoluble vitamins (A, D, E, and K) and carotenoids have many benefits on health. They are provided mainly by foods. At pharmacological doses, they can also be used to treat skin diseases, several types of cancer or decrease oxidative stress. These molecules are sensitive to oxidation, thus encapsulation might constitute an appropriate mean to preserve their properties during storage and enhance their physiological potencies. Formulation processes have been adapted for sensitive molecule, limiting their exposure to high temperature, light or oxygen. Each administration pathway, oral, systemic, topical, transdermal and local, requires different particle sizes and release profile. Encapsulation can lead to greater efficiency allowing smaller administration doses thus diminishing potential hypervitaminosis syndrome appearance and side effects. Carrier formulation can be based on vitamin dissolution in lipid media and its stabilization by surfactant mixture, on its entrapment in a matrix or molecular system. Suitability of each type of carrier will be discussed for each pathway. 2010 Elsevier B.V. All rights reserved.

Preparation and optimization of matrix metalloproteinase-1-loaded poly(lactide- co-glycolide- co-caprolactone) nanoparticles with rotatable central composite design and response surface methodology

NASA Astrophysics Data System (ADS)

Sun, Ping; Song, Hua; Cui, Daxiang; Qi, Jun; Xu, Mousheng; Geng, Hongquan

2012-07-01

Matrix metalloproteases are key regulatory molecules in the breakdown of extracellular matrix and in inflammatory processes. Matrix metalloproteinase-1 (MMP-1) can significantly enhance muscle regeneration by promoting the formation of myofibers and degenerating the fibrous tissue. Herein, we prepared novel MMP-1-loaded poly(lactide-co-glycolide-co-caprolactone) (PLGA-PCL) nanoparticles (NPs) capable of sustained release of MMP-1. We established quadratic equations as mathematical models and employed rotatable central composite design and response surface methodology to optimize the preparation procedure of the NPs. Then, characterization of the optimized NPs with respect to particle size distribution, particle morphology, drug encapsulation efficiency, MMP-1 activity assay and in vitro release of MMP-1 from NPs was carried out. The results of mathematical modeling show that the optimal conditions for the preparation of MMP-1-loaded NPs were as follows: 7 min for the duration time of homogenization, 4.5 krpm for the agitation speed of homogenization and 0.4 for the volume ratio of organic solvent phase to external aqueous phase. The entrapment efficiency and the average particle size of the NPs were 38.75 ± 4.74% and 322.7 ± 18.1 nm, respectively. Further scanning electron microscopy image shows that the NPs have a smooth and spherical surface, with mean particle size around 300 nm. The MMP-1 activity assay and in vitro drug release profile of NPs indicated that the bioactivity of the enzyme can be reserved where the encapsulation allows prolonged release of MMP-1 over 60 days. Taken together, we reported here novel PLGA-PCL NPs for sustained release of MMP-1, which may provide an ideal MMP-1 delivery approach for tissue reconstruction therapy.

Gravity-induced encapsulation of liquids by destabilization of granular rafts

NASA Astrophysics Data System (ADS)

Abkarian, Manouk; Protière, Suzie; Aristoff, Jeffrey M.; Stone, Howard A.

2013-05-01

Droplets and bubbles coated by a protective armour of particles find numerous applications in encapsulation, stabilization of emulsions and foams, and flotation techniques. Here we study the role of a body force, such as in flotation, as a means of continuous encapsulation by particles. We use dense particles, which self-assemble into rafts, at oil-water interfaces. We show that these rafts can be spontaneously or controllably destabilized into armoured oil-in-water droplets, which highlights a possible role for common granular materials in environmental remediation. We further present a method for continuous production and discuss the generalization of our approach towards colloidal scales.

Preparation and encapsulation of white/yellow dual colored suspensions for electrophoretic displays

NASA Astrophysics Data System (ADS)

Han, Jingjing; Li, Xiaoxu; Feng, Yaqing; Zhang, Bao

2014-11-01

C.I. Pigment Yellow 181 (PY181) composite particles encapsulated by polyethylene (PE) were prepared by dispersion polymerization method, and C.I. Pigment Yellow 110 (PY110) composite particles encapsulated by polystyrene (PS) with mini-emulsion polymerization method were achieved, respectively. The modified pigments were characterized by fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope. Compared with the PE-coated PY 181 pigments, the PS-coated PY-110 particles had a narrow particle size distribution, regular spherical and average particle size of 450 nm. Suspension 1 and suspension 3 were prepared by the two composite particles dispersed in isopar M. A chromatic electrophoretic display cell consisting of yellow particles was successfully fabricated using dispersions of yellow ink particles in a mixed dielectric solvent with white particles as contrast. The response behavior and the contrast ratio to the electric voltage were also examined. The contrast ratio of pigments modified by polystyrene was 1.48, as well as the response time was 2 s, which were better than those of pigments modified by polyethylene.

Application of cashew tree gum on the production and stability of spray-dried fish oil.

PubMed

Botrel, Diego Alvarenga; Borges, Soraia Vilela; Fernandes, Regiane Victória de Barros; Antoniassi, Rosemar; de Faria-Machado, Adelia Ferreira; Feitosa, Judith Pessoa de Andrade; de Paula, Regina Celia Monteiro

2017-04-15

Evaluation of cashew gum compared to conventional materials was conducted regarding properties and oxidative stability of spray-dried fish oil. Emulsions produced with cashew gum showed lower viscosity when compared to Arabic gum. The particle size was larger (29.9μm) when cashew gum was used, and the encapsulation efficiency reached 76%, similar to that of modified starch but higher than that for Arabic gum (60%). The oxidation process for the surface oil was conducted and a relative lower formation of oxidation compounds was observed for the cashew gum treatment. GAB model was chosen to describe the moisture adsorption isotherm behaviours. Microparticles produced using Arabic and cashew gums showed greater water adsorption when exposed to higher relative humidities. Microparticles produced using cashew gum were more hygroscopic however encapsulation efficiency were higher and surface oil oxidation were less pronounced. Cashew gum can be further explored as an encapuslant material for spray drying processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis and characterization of chitosan quaternary ammonium salt and its application as drug carrier for ribavirin.

PubMed

Li, Si-Dong; Li, Pu-Wang; Yang, Zi-Ming; Peng, Zheng; Quan, Wei-Yan; Yang, Xi-Hong; Yang, Lei; Dong, Jing-Jing

2014-11-01

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is hydro-soluble chitosan (CS) derivative, which can be obtained by the reaction between epoxypropyl trimethyl ammonium chloride (ETA) and CS. The preparation parameters for the synthesis of HTCC were optimized by orthogonal experimental design. ETA was successfully grafted into the free amino group of CS. Grafting of ETA with CS had great effect on the crystal structure of HTCC, which was confirmed by the XRD results. HTCC displayed higher capability to form nanoparticles by crosslinking with negatively charged sodium tripolyphosphate (TPP). Ribavrin- (RIV-) loaded HTCC nanoparticles were positively charged and were spherical in shape with average particle size of 200 nm. More efficient drug encapsulation efficiency and loading capacity were obtained for HTCC in comparison with CS, however, HTCC nanoparticles displayed faster release rate due to its hydro-soluble properties. The results suggest that HTCC is a promising CS derivative for the encapsulation of hydrophilic drugs in obtaining sustained release of drugs.

Microfluidic Encapsulation of Prickly Zinc-Doped Copper Oxide Nanoparticles with VD1142 Modified Spermine Acetalated Dextran for Efficient Cancer Therapy.

PubMed

Zhang, Hongbo; Liu, Dongfei; Wang, Liang; Liu, Zehua; Wu, Runrun; Janoniene, Agne; Ma, Ming; Pan, Guoqing; Baranauskiene, Lina; Zhang, Linlin; Cui, Wenguo; Petrikaite, Vilma; Matulis, Daumantas; Zhao, Hongxia; Pan, Jianming; Santos, Hélder A

2017-06-01

Structural features of nanoparticles have recently been explored for different types of applications. To explore specific particles as nanomedicine and physically destroy cancer is interesting, which might avoid many obstacles in cancer treatment, for example, drug resistance. However, one key element and technical challenge of those systems is to selectively target them to cancer cells. As a proof-of-concept, Prickly zinc-doped copper oxide (Zn-CuO) nanoparticles (Prickly NPs) have been synthesized, and subsequently encapsulated in a pH-responsive polymer; and the surface has been modified with a novel synthesized ligand, 3-(cyclooctylamino)-2,5,6-trifluoro-4-[(2-hydroxyethyl)sulfonyl] benzenesulfonamide (VD1142). The Prickly NPs exhibit very effective cancer cell antiproliferative capability. Moreover, the polymer encapsulation shields the Prickly NPs from unspecific nanopiercing and, most importantly, VD1142 endows the engineered NPs to specifically target to the carbonic anhydrase IX, a transmembrane protein overexpressed in a wide variety of cancer tumors. Intracellularly, the Prickly NPs disintegrate into small pieces that upon endosomal escape cause severe damage to the endoplasmic reticulum and mitochondria of the cells. The engineered Prickly NP is promising in efficient and targeted cancer treatment and it opens new avenue in nanomedication. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Curcumin-encapsulated polymeric micelles suppress the development of colon cancer in vitro and in vivo.

PubMed

Yang, Xi; Li, Zhaojun; Wang, Ning; Li, Ling; Song, Linjiang; He, Tao; Sun, Lu; Wang, Zhihan; Wu, Qinjie; Luo, Na; Yi, Cheng; Gong, Changyang

2015-05-18

To develop injectable formulation and improve the stability of curcumin (Cur), Cur was encapsulated into monomethyl poly (ethylene glycol)-poly (ε-caprolactone)-poly (trimethylene carbonate) (MPEG-P(CL-co-TMC)) micelles through a single-step solid dispersion method. The obtained Cur micelles had a small particle size of 27.6 ± 0.7 nm with polydisperse index (PDI) of 0.11 ± 0.05, drug loading of 14.07 ± 0.94%, and encapsulation efficiency of 96.08 ± 3.23%. Both free Cur and Cur micelles efficiently suppressed growth of CT26 colon carcinoma cells in vitro. The results of in vitro anticancer studies confirmed that apoptosis induction and cellular uptake on CT26 cells had completely increased in Cur micelles compared with free Cur. Besides, Cur micelles were more effective in suppressing the tumor growth of subcutaneous CT26 colon in vivo, and the mechanisms included the inhibition of tumor proliferation and angiogenesis and increased apoptosis of tumor cells. Furthermore, few side effects were found in Cur micelles. Overall, our findings suggested that Cur micelles could be a stabilized aqueous formulation for intravenous application with improved antitumor activity, which may be a potential treatment strategy for colon cancer in the future.

Dorzolamide Loaded Niosomal Vesicles: Comparison of Passive and Remote Loading Methods

PubMed Central

Hashemi Dehaghi, Mohadeseh; Haeri, Azadeh; Keshvari, Hamid; Abbasian, Zahra; Dadashzadeh, Simin

2017-01-01

Glaucoma is a common progressive eye disorder and the treatment strategies will benefit from nanoparticulate delivery systems with high drug loading and sustained delivery of intraocular pressure lowering agents. Niosomes have been reported as a novel approach to improve drug low corneal penetration and bioavailability characteristics. Along with this, poor entrapment efficiency of hydrophilic drug in niosomal formulation remains as a major formulation challenge. Taking this perspective into consideration, dorzolamide niosomes were prepared employing two different loading methodologies (passive and remote loading methods) and the effects of various formulation variables (lipid to drug ratio, cholesterol percentage, drug concentration, freeze/thaw cycles, TPGS content, and external and internal buffer molarity and pH) on encapsulation efficiency were assessed. Encapsulation of dorzolamide within niosomes increased remarkably by the incorporation of higher cholesterol percentage as well as increasing the total lipid concentration. Remote loading method showed higher efficacy for drug entrapment compared to passive loading technique. Incorporation of TPGS in bilayer led to decrease in EE; however, retarded drug release rate. Scanning electron microscopy (SEM) studies confirmed homogeneous particle distribution, and spherical shape with smooth surface. In conclusion, the highest encapsulation can be obtained using phosphate gradient method and 50% cholesterol in Span 60 niosomal formulation. PMID:28979296

Ibuprofen-in-cyclodextrin-in-W/O/W emulsion - Improving the initial and long-term encapsulation efficiency of a model active ingredient.

PubMed

Hattrem, Magnus N; Kristiansen, Kåre A; Aachmann, Finn L; Dille, Morten J; Draget, Kurt I

2015-06-20

A challenge in formulating water-in-oil-in-water (W/O/W) emulsions is the uncontrolled release of the encapsulated compound prior to application. Pharmaceuticals and nutraceuticals usually have amphipathic nature, which may contribute to leakage of the active ingredient. In the present study, cyclodextrins (CyDs) were used to impart a change in the relative polarity and size of a model compound (ibuprofen) by the formation of inclusion complexes. Various inclusion complexes (2-hydroxypropyl (HP)-β-CyD-, α-CyD- and γ-CyD-ibuprofen) were prepared and presented within W/O/W emulsions, and the initial and long-term encapsulation efficiency was investigated. HP-β-CyD-ibuprofen provided the highest encapsulation of ibuprofen in comparison to a W/O/W emulsion with unassociated ibuprofen confined within the inner water phase, with a four-fold increase in the encapsulation efficiency. An improved, although lower, encapsulation efficiency was obtained for the inclusion complex γ-CyD-ibuprofen in comparison to HP-β-CyD-ibuprofen, whereas α-CyD-ibuprofen had a similar encapsulation efficiency to that of unassociated ibuprofen. The lower encapsulation efficiency of ibuprofen in combination with α-CyD and γ-CyD was attributed to a lower association constant for the γ-CyD-ibuprofen inclusion complex and the ability of α-CyD to form inclusion complexes with fatty acids. For the W/O/W emulsion prepared with HP-β-CyD-ibuprofen, the highest encapsulation of ibuprofen was obtained at hyper- and iso-osmotic conditions and by using an excess molar ratio of CyD to ibuprofen. In the last part of the study, it was suggested that the chemical modification of the HP-β-CyD molecule did not influence the encapsulation of ibuprofen, as a similar encapsulation efficiency was obtained for an inclusion complex prepared with mono-1-glucose-β-CyD. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization Methods of Encapsulates

NASA Astrophysics Data System (ADS)

Zhang, Zhibing; Law, Daniel; Lian, Guoping

Food active ingredients can be encapsulated by different processes, including spray drying, spray cooling, spray chilling, spinning disc and centrifugal co-extrusion, extrusion, fluidized bed coating and coacervation (see Chap. 2 of this book). The purpose of encapsulation is often to stabilize an active ingredient, control its release rate and/or convert a liquid formulation into a solid which is easier to handle. A range of edible materials can be used as shell materials of encapsulates, including polysaccharides, fats, waxes and proteins (see Chap. 3 of this book). Encapsulates for typical industrial applications can vary from several microns to several millimetres in diameter although there is an increasing interest in preparing nano-encapsulates. Encapsulates are basically particles with a core-shell structure, but some of them can have a more complex structure, e.g. in a form of multiple cores embedded in a matrix. Particles have physical, mechanical and structural properties, including particle size, size distribution, morphology, surface charge, wall thickness, mechanical strength, glass transition temperature, degree of crystallinity, flowability and permeability. Information about the properties of encapsulates is very important to understanding their behaviours in different environments, including their manufacturing processes and end-user applications. E.g. encapsulates for most industrial applications should have desirable mechanical strength, which should be strong enough to withstand various mechanical forces generated in manufacturing processes, such as mixing, pumping, extrusion, etc., and may be required to be weak enough in order to release the encapsulated active ingredients by mechanical forces at their end-user applications, such as release rate of flavour by chewing. The mechanical strength of encapsulates and release rate of their food actives are related to their size, morphology, wall thickness, chemical composition, structure etc. Hence, reliable methods which can be used to characterize these properties of encapsulates are vital. In this chapter, the state-of-art of these methods, their principles and applications, and release mechanisms are described as follows.

Dual-modality, fluorescent, PLGA encapsulated bismuth nanoparticles for molecular and cellular fluorescence imaging and computed tomography

NASA Astrophysics Data System (ADS)

Swy, Eric R.; Schwartz-Duval, Aaron S.; Shuboni, Dorela D.; Latourette, Matthew T.; Mallet, Christiane L.; Parys, Maciej; Cormode, David P.; Shapiro, Erik M.

2014-10-01

Reports of molecular and cellular imaging using computed tomography (CT) are rapidly increasing. Many of these reports use gold nanoparticles. Bismuth has similar CT contrast properties to gold while being approximately 1000-fold less expensive. Herein we report the design, fabrication, characterization, and CT and fluorescence imaging properties of a novel, dual modality, fluorescent, polymer encapsulated bismuth nanoparticle construct for computed tomography and fluorescence imaging. We also report on cellular internalization and preliminary in vitro and in vivo toxicity effects of these constructs. 40 nm bismuth(0) nanocrystals were synthesized and encapsulated within 120 nm Poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles by oil-in-water emulsion methodologies. Coumarin-6 was co-encapsulated to impart fluorescence. High encapsulation efficiency was achieved ~70% bismuth w/w. Particles were shown to internalize within cells following incubation in culture. Bismuth nanocrystals and PLGA encapsulated bismuth nanoparticles exhibited >90% and >70% degradation, respectively, within 24 hours in acidic, lysosomal environment mimicking media and both remained nearly 100% stable in cytosolic/extracellular fluid mimicking media. μCT and clinical CT imaging was performed at multiple X-ray tube voltages to measure concentration dependent attenuation rates as well as to establish the ability to detect the nanoparticles in an ex vivo biological sample. Dual fluorescence and CT imaging is demonstrated as well. In vivo toxicity studies in rats revealed neither clinically apparent side effects nor major alterations in serum chemistry and hematology parameters. Calculations on minimal detection requirements for in vivo targeted imaging using these nanoparticles are presented. Indeed, our results indicate that these nanoparticles may serve as a platform for sensitive and specific targeted molecular CT and fluorescence imaging.Reports of molecular and cellular imaging using computed tomography (CT) are rapidly increasing. Many of these reports use gold nanoparticles. Bismuth has similar CT contrast properties to gold while being approximately 1000-fold less expensive. Herein we report the design, fabrication, characterization, and CT and fluorescence imaging properties of a novel, dual modality, fluorescent, polymer encapsulated bismuth nanoparticle construct for computed tomography and fluorescence imaging. We also report on cellular internalization and preliminary in vitro and in vivo toxicity effects of these constructs. 40 nm bismuth(0) nanocrystals were synthesized and encapsulated within 120 nm Poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles by oil-in-water emulsion methodologies. Coumarin-6 was co-encapsulated to impart fluorescence. High encapsulation efficiency was achieved ~70% bismuth w/w. Particles were shown to internalize within cells following incubation in culture. Bismuth nanocrystals and PLGA encapsulated bismuth nanoparticles exhibited >90% and >70% degradation, respectively, within 24 hours in acidic, lysosomal environment mimicking media and both remained nearly 100% stable in cytosolic/extracellular fluid mimicking media. μCT and clinical CT imaging was performed at multiple X-ray tube voltages to measure concentration dependent attenuation rates as well as to establish the ability to detect the nanoparticles in an ex vivo biological sample. Dual fluorescence and CT imaging is demonstrated as well. In vivo toxicity studies in rats revealed neither clinically apparent side effects nor major alterations in serum chemistry and hematology parameters. Calculations on minimal detection requirements for in vivo targeted imaging using these nanoparticles are presented. Indeed, our results indicate that these nanoparticles may serve as a platform for sensitive and specific targeted molecular CT and fluorescence imaging. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01405g

On the temporal variation of leaf magnetic parameters: seasonal accumulation of leaf-deposited and leaf-encapsulated particles of a roadside tree crown.

PubMed

Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Samson, Roeland

2014-09-15

Understanding the accumulation behaviour of atmospheric particles inside tree leaves is of great importance for the interpretation of biomagnetic monitoring results. In this study, we evaluated the temporal variation of the saturation isothermal remanent magnetisation (SIRM) of leaves of a roadside urban Platanus × acerifolia Willd. tree in Antwerp, Belgium. We hereby examined the seasonal development of the total leaf SIRM signal as well as the leaf-encapsulated fraction of the deposited dust, by washing the leaves before biomagnetic analysis. On average 38% of the leaf SIRM signal was exhibited by the leaf-encapsulated particles. Significant correlations were found between the SIRM and the cumulative daily average atmospheric PM10 and PM2.5 measurements. Moreover, a steady increase of the SIRM throughout the in-leaf season was observed endorsing the applicability of biomagnetic monitoring as a proxy for the time-integrated PM exposure of urban tree leaves. Strongest correlations were obtained for the SIRM of the leaf-encapsulated particles which confirms the dynamic nature of the leaf surface-accumulated particles. Copyright © 2014 Elsevier B.V. All rights reserved.

PEG-PLA-PEG block copolymeric nanoparticles for oral immunization against hepatitis B.

PubMed

Jain, Arvind K; Goyal, Amit K; Mishra, Neeraj; Vaidya, Bhuvaneshwar; Mangal, Sharad; Vyas, Suresh P

2010-03-15

PLA/PLGA nanoparticles are well known as efficient vaccine delivery systems, but they have got limitation in oral vaccine delivery because of their sensitivity to harsh gastric environment. The aim of present study was to improve the stability of PLA nanoparticles in such environment by copolymerizing PLA with PEG. Nanoparticles were formulated using different block copolymers AB, ABA and BAB (where 'A' is PLA and 'B' is PEG) encapsulating hepatitis B surface antigen (HBsAg) to evaluate their efficacy as oral vaccine delivery system. The results of in vitro studies engrave the efficiency of copolymeric nanoparticles to retain encapsulated antigen and average particle size even after 2 h incubation in simulated gastric fluid and simulated intestinal fluid. Fluorescence microscopic studies indicated efficient uptake of copolymeric nanoparticles by gut mucosa of immunized mice model as compared to control. Finally copolymeric and PLA nanoparticles, encapsulating HBsAg, were evaluated for their adjuvancity in generating immune response after oral administration. PLA nanoparticles could not generate an effective immune response due to stability issues. On the other hand, oral administration of copolymeric nanoparticles exhibited effective levels of humoral immunity along with the mucosal (sIgA) and cellular immune response (T(H)1). The results of in vitro and in vivo studies demonstrate that BAB nanoparticles depict enhanced mucosal uptake leading to effective immune response as compared to other copolymeric nanoparticles. Present study indicates the efficacy of BAB nanoparticles as a promising carrier for oral immunization. 2009 Elsevier B.V. All rights reserved.

Development of biodegradable drug delivery system to treat addiction.

PubMed

Mandal, T K

1999-06-01

Opiate addiction is a serious problem that has now spread worldwide to all levels of society. Buprenorphine has been used for several years for the treatment of opiate addiction. The objective of this project was to develop sustained-release biodegradable microcapsules for the parenteral delivery of buprenorphine. Biodegradable microcapsules of buprenorphine/poly(lactide-co-glycolide) were prepared using two main procedures based on an in-water drying process in a complex emulsion system. These procedures differ in the way the organic solvent was eliminated: evaporation or extraction. The effect of drug loading and the effect of partial saturation of the aqueous phase with the core material during the in-water solvent evaporation were also studied. The efficiency of encapsulation increased from 11% to 34% when the drug loading was decreased from 20% to 5%. There was no significant change in the efficiency of encapsulation when the aqueous phase was partially saturated with buprenorphine. In changing the solvent removal process from evaporation to extraction, no significant change in the efficiency of encapsulation was observed. The microcapsules prepared by the solvent evaporation were smooth and spherical. However, the microcapsules prepared by the extraction of the organic solvent lost their surface smoothness and became slightly irregular and porous compared with the other batches. The average particle size of the microcapsules was between 14 and 49 microns. The cumulative drug release was between 2% and 4% within the first 24 hr. A sustained drug release continued over 45 days.

In situ forming biodegradable poly(ε-caprolactone) microsphere systems: a challenge for transarterial embolization therapy. In vitro and preliminary ex vivo studies.

PubMed

Salis, Andrea; Porcu, Elena P; Gavini, Elisabetta; Fois, Giulia R; Icaro Cornaglia, Antonia; Rassu, Giovanna; Diana, Marco; Maestri, Marcello; Giunchedi, Paolo; Nikolakakis, Ioannis

2017-04-01

In situ forming biodegradable poly(ε-caprolactone) (PCL) microspheres (PCL-ISM) system was developed as a novel embolic agent for transarterial embolization (TAE) therapy of hepatocellular carcinoma (HCC). Ibuprofen sodium (Ibu-Na) was loaded on this platform to evaluate its potential for the treatment of post embolization syndrome. The influence of formulation parameters on the size/shape, encapsulation efficiency and drug release was investigated using mixture experimental design. Regression models were derived and used to optimize the formulation for particle size, encapsulation efficiency and drug release profile for TAE therapy. An ex vivo model using isolated rat livers was established to assess the in situ formation of microspheres. All PCL-ISM components affected the studied properties and fitting indices of the regression models were high (Radj 2  = 0.810 for size, 0.964 encapsulation efficiency, and 0.993 or 0.971 for drug release at 30 min or 48 h). The optimized composition was: PCL = 4%, NMP = 43.1%, oil = 48.9%, surfactant = 2% and drug = 2%. Ex vivo studies revealed that PCL-ISM was able to form microspheres in the hepatic arterial bed. PCL-ISM system provides a novel tool for the treatment of HCC and post-embolization syndrome. It is capable of forming microspheres with desirable size and Ibu-Na release profile after injection into blood vessels.

Positively Charged Nanostructured Lipid Carriers and Their Effect on the Dissolution of Poorly Soluble Drugs.

PubMed

Choi, Kyeong-Ok; Choe, Jaehyeog; Suh, Seokjin; Ko, Sanghoon

2016-05-20

The objective of this study is to develop suitable formulations to improve the dissolution rate of poorly water soluble drugs. We selected lipid-based formulation as a drug carrier and modified the surface using positively charged chitosan derivative (HTCC) to increase its water solubility and bioavailability. Chitosan and HTCC-coated lipid particles had higher zeta-potential values than uncoated one over the whole pH ranges and improved encapsulation efficiency. In vitro drug release showed that all NLC formulations showed higher in vitro release efficiency than drug particle at pH 7.4. Furthermore, NLC formulation prepared with chitosan or HTCC represented good sustained release property. The results indicate that chitosan and HTCC can be excellent formulating excipients of lipid-based delivery carrier for improving poorly water soluble drug delivery.

Preparation of a nano emodin transfersome and study on its anti-obesity mechanism in adipose tissue of diet-induced obese rats

PubMed Central

2014-01-01

Objective To describe the preparation of nano emodin transfersome (NET) and investigate its effect on mRNA expression of adipose triglyceride lipase (ATGL) and G0/G1 switch gene 2 (G0S2) in adipose tissue of diet-induced obese rats. Methods NET was prepared by film-ultrasonic dispersion method. The effects of emodin components at different ratios on encapsulation efficiency were investigated.The NET envelopment rate was determined by ultraviolet spectrophotometry. The particle size and Zeta potential of NET were evaluated by Zetasizer analyzer. Sixty male SD rats were assigned to groups randomly. After 8-week treatment, body weight, wet weight of visceral fat and the percentage of body fat (PBF) were measured. Fasting blood glucose and serum lipid levels were determined. The adipose tissue section was HE stained, and the cellular diameter and quantity of adipocytes were evaluated by light microscopy. The mRNA expression of ATGL and G0S2 from the peri-renal fat tissue was assayed by RT-PCR. Results The appropriate formulation was deoxycholic acid sodium salt vs. phospholipids 1:8, cholesterol vs. phospholipids 1:3, vitamin Evs. phospholipids 1:20, and emodin vs. phospholipid 1:6. Zeta potential was −15.11 mV, and the particle size was 292.2 nm. The mean encapsulation efficiency was (69.35 ± 0.25)%. Compared with the obese model group, body weight, wet weight of visceral fat, PBF and mRNA expression of G0S2 from peri-renal fat tissue were decreased significantly after NET treatment (all P < 0.05), while high-density lipoprotein cholesterol (HDL-C), the diameter of adipocytes and mRNA expression of ATGL from peri-renal fat tissue were increased significantly (all P < 0.05). Conclusion The preparation method is simple and reasonable. NET with negative electricity was small and uniform in particle size, with high encapsulation efficiency and stability. NET could reduce body weight and adipocyte size, and this effect was associated with the up-regulation of ATGL, down-regulation of G0S2 expression in the adipose tissue, and improved insulin sensitivity. PMID:24641917

Annatto Polymeric Microparticles: Natural Product Encapsulation by the Emulsion-Solvent Evaporation Method

ERIC Educational Resources Information Center

Teixeira, Zaine; Duran, Nelson; Guterres, Silvia S.

2008-01-01

In this experiment, the extract from annatto seeds was encapsulated in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) particles by the emulsion-solvent evaporation method. The particles were washed and centrifuged to remove excess stabilizer and then freeze-dried. The main compound of annatto seeds, bixin, has antioxidant properties as well…

Melatonin releasing PLGA micro/nanoparticles and their effect on osteosarcoma cells.

PubMed

Altındal, Damla Çetin; Gümüşderelioğlu, Menemşe

2016-02-01

Melatonin loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles and microparticles in the diameter of ∼200 nm and 3.5 μm, respectively, were prepared by emulsion-diffusion-evaporation method. Melatonin entrapment into the particles was significantly improved with the addition of 0.2% (w/v) melatonin into the aqueous phase and encapsulation efficiencies were found as 14 and 27% for nanoparticles and microparticles, respectively. At the end of 40 days, ∼70% of melatonin was released from both of particles, with high burst release. Both blank and melatonin loaded PLGA nanoparticles caused toxic effect on the MG-63 cells due to their uptake by the cells. However, when 0.05 mg microparticle that is carrying ∼1.7 μg melatonin was added to the cm(2) of culture, inhibitory effect of melatonin on the cells were obviously observed. The results would provide an expectation about the usage of melatonin as an adjunct to the routine chemotherapy of osteosarcoma by encapsulating it into a polymeric carrier system.

Biodegradable nanoparticles for improved kidney bioavailability of rhein: preparation, characterization, plasma, and kidney pharmacokinetics.

PubMed

Wei, Yinghui; Luo, Xiaoting; Guan, Jiani; Ma, Jianping; Zhong, Yicong; Luo, Jingwen; Li, Fanzhu

2017-11-01

The aim of this work is to develop biodegradable nanoparticles for improved kidney bioavailability of rhein (RH). RH-loaded nanoparticles were prepared using an emulsification solvent evaporation method and fully characterized by several techniques. Kidney pharmacokinetics was assessed by implanting a microdialysis probe in rat's kidney cortex. Blood samples were simultaneously collected (via femoral artery) for assessing plasma pharmacokinetics. Optimized nanoparticles were small, with a mean particle size of 132.6 ± 5.95 nm, and homogeneously dispersed. The charge on the particles was nearly zero, the encapsulation efficiency was 62.71 ± 3.02%, and the drug loading was 1.56 ± 0.15%. In vitro release of RH from the nanoparticles showed an initial burst release followed by a sustained release. Plasma and kidney pharmacokinetics showed that encapsulation of RH into nanoparticles significantly increased its kidney bioavailability (AUC kidney /AUC plasma  = 0.586 ± 0.072), clearly indicating that nanoparticles are a promising strategy for kidney drug delivery.

Protein-Containing Multilayer Capsules by Templating on Mesoporous CaCO3 Particles: POST- and PRE-Loading Approaches.

PubMed

Balabushevich, Nadezhda G; Lopez de Guerenu, Anna V; Feoktistova, Natalia A; Skirtach, Andre G; Volodkin, Dmitry

2016-01-01

Encapsulation of model proteins (catalase, insulin, aprotinin) into multilayer dextran sulphate/protamin capsules by templating on CaCO3 microparticles is investigated employing: (i) PRE-loading into CaCO3 particles by adsorption or co-synthesis and (ii) POST-loading into performed capsules. Protein encapsulation is governed by both its size and electrostatic interactions with the carbonate microparticles and multilayer shell. PRE-loading enables improved encapsulation compared to POST-loading (catalase content in capsules 630 and 70 mg · g(-1)). Bioactivity of encapsulated protein is not affected by interaction with multilayers but may be reduced at slightly alkaline pH due to CaCO3 hydrolysis. This study might help to successfully encapsulate fragile bio-macromolecules into multilayer capsules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

pH Reversible Encapsulation of Oppositely Charged Colloids Mediated by Polyelectrolytes

PubMed Central

2017-01-01

We report the first example of reversible encapsulation of micron-sized particles by oppositely charged submicron smaller colloids. The reversibility of this encapsulation process is regulated by pH-responsive poly(acrylic acid) (PAA) present in solution. The competitive adsorption between the small colloids and the poly(acrylic acid) on the surface of the large colloids plays a key role in the encapsulation behavior of the system. pH offers an experimental knob to tune the electrostatic interactions between the two oppositely charged particle species via regulation of the charge density of the poly(acrylic acid). This results in an increased surface coverage of the large colloids by the smaller colloids when decreasing pH. Furthermore, the poly(acrylic acid) also acts as a steric barrier limiting the strength of the attractive forces between the oppositely charged particle species, thereby enabling detachment of the smaller colloids. Finally, based on the pH tunability of the encapsulation behavior and the ability of the small colloids to detach, reversible encapsulation is achieved by cycling pH in the presence of the PAA polyelectrolytes. The role of polyelectrolytes revealed in this work provides a new and facile strategy to control heteroaggregation behavior between oppositely charged colloids, paving the way to prepare sophisticated hierarchical assemblies. PMID:28419800

Formulation and characterization of ORMOSIL particles loaded with budesonide for local colonic delivery.

PubMed

Petrovska-Jovanovska, Vesna; Geskovski, Nikola; Crcarevska, Maja Simonoska; Memed, Oya; Petruševski, Gjorgji; Chachorovska, Marina; Petrusevska, Marija; Poceva-Panovska, Ana; Mladenovska, Kristina; Ugarkovic, Sonja; Glavas-Dodov, Marija

2015-04-30

In this study, hybrid silica xerogel particles were developed as carriers of budesonide (BDS) for efficient local treatment of inflammatory bowel diseases (IBD). Organically modified silica particles (ORMOSILs) were prepared by co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) by an ambient temperature acid catalysed sol-gel process followed by spray-drying. Formulation for preparation of BDS-loaded particles was optimized and their physicochemical parameters and drug release profiles were evaluated in vitro. Optimal formulation had a small particle size (mean diameter of 1.45±0.02μm) with unimodal narrow size distribution and high encapsulation efficiency (98.0 ± 1.85%). Due to the positive surface charge originated from amino group of APTES, ORMOSILs showed excessive mucoadhesiveness in comparison to native TEOS particles. The drug release decreased with increasing pH from 2.0 to 7.4. In order to avoid undesirable erroneous performance in the upper GI tract, particles were additionally coated with Eudragit(®) FS 30D, as a barrier to the drug release at pH range from 2.0 to 7.0. After Eudragit(®) FS 30D coating, the release of BDS in acidic media was sustained, while no significant differences in drug release were observed at pH 7.4. In conclusion, pH-responsive ORMOSILs showed great potential for efficient BDS delivery to the colon region. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimized zein nanospheres for improved oral bioavailability of atorvastatin

PubMed Central

Hashem, Fahima M; Al-Sawahli, Majid M; Nasr, Mohamed; Ahmed, Osama AA

2015-01-01

Background This work focuses on the development of atorvastatin utilizing zein, a natural, safe, and biocompatible polymer, as a nanosized formulation in order to overcome the poor oral bioavailability (12%) of the drug. Methods Twelve experimental runs of atorvastatin–zein nanosphere formula were formulated by a liquid–liquid phase separation method according to custom fractional factorial design to optimize the formulation variables. The factors studied were: weight % of zein to atorvastatin (X1), pH (X2), and stirring time (X3). Levels for each formulation variable were designed. The selected dependent variables were: mean particle size (Y1), zeta potential (Y2), drug loading efficiency (Y3), drug encapsulation efficiency (Y4), and yield (Y5). The optimized formulation was assayed for compatibility using an X-ray diffraction assay. In vitro diffusion of the optimized formulation was carried out. A pharmacokinetic study was also done to compare the plasma profile of the atorvastatin–zein nanosphere formulation versus atorvastatin oral suspension and the commercially available tablet. Results The optimized atorvastatin–zein formulation had a mean particle size of 183 nm, a loading efficiency of 14.86%, and an encapsulation efficiency of 29.71%. The in vitro dissolution assay displayed an initial burst effect, with a cumulative amount of atorvastatin released of 41.76% and 82.3% after 12 and 48 hours, respectively. In Wistar albino rats, the bioavailability of atorvastatin from the optimized atorvastatin–zein formulation was 3-fold greater than that from the atorvastatin suspension and the commercially available tablet. Conclusion The atorvastatin–zein nanosphere formulation improved the oral delivery and pharmacokinetic profile of atorvastatin by enhancing its oral bioavailability. PMID:26150716

Dexamethasone acetate encapsulation into Trojan particles.

PubMed

Gómez-Gaete, Carolina; Fattal, Elias; Silva, Lídia; Besnard, Madeleine; Tsapis, Nicolas

2008-05-22

We have combined the therapeutic potential of nanoparticles systems with the ease of manipulation of microparticles by developing a hybrid vector named Trojan particles. We aim to use this new delivery vehicle for intravitreal administration of dexamethasone. Initialy, dexamethasone acetate (DXA) encapsulation into biodegradable poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was optimized. Then, Trojan particles were formulated by spray drying 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC), hyaluronic acid (HA) and different concentrations of nanoparticle suspensions. The effect of nanoparticles concentration on Trojan particle physical characteristics was investigated as well as the effect of the spray drying process on nanoparticles size. Finally, DXA in vitro release from nanoparticles and Trojan particles was evaluated under sink condition. SEM and confocal microscopy show that most of Trojan particles are spherical, hollow and possess an irregular surface due to the presence of nanoparticles. Neither Trojan particle tap density nor size distribution are significantly modified as a function of nanoparticles concentration. The mean nanoparticles size increase significantly after spray drying. Finally, the in vitro release of DXA shows that the excipient matrix provides protection to encapsulated nanoparticles by slowing drug release.

Encapsulation of bioactive compound from extracted jasmine flower using β-Cyclodextrin via electrospray

NASA Astrophysics Data System (ADS)

Rahmam., S.; Naim., M. N.; Ng., E.; Mokhtar, M. Nn; Abu Bakar, N. F.

2016-06-01

The ability of electrospray to encapsulate the bioactive compound extracted from Jasmine flower with β-Cyclodextrion (β-CD) without any thermal-assisted processing was demonstrated in this study. The extraction of Jasmine compound were conducted using sonicator at 70 000 Hz, for 10 minutes and followed by mixing of the filtered compound with β-CD. Then, the mixture was electrosprayed under a stable Taylor cone jet mode at the voltage of 4 - 5 kV, with flow rate of 0.2 ml/hour. The aluminum substrate that used for collecting the deposit was placed at 30 cm from the needle's tip to allow the occurrence of evaporation and droplet fission until the droplet transform to solid particles. Characteristics of solidified bioactive compound from Jasmine flower (non-encapsulated compound) and solidified bioactive compound with β-CD (encapsulated compound) were studied in this work. From SEM images, it can be observed that the particles size distribution of encapsulated compound deposits have better deposition array and did not aggregate with each other compared to the non-encapsulated compound. FE-SEM images of encapsulated compound deposits indicate more solid crystal looks while non-encapsulated compound was obtained in the porous form. The electrospray process in this work has successfully encapsulated the Jasmine compound with β-CD without any thermal-assisted process. The encapsulation occurrence was determined using FTIR analysis. Identical peaks that referred to the β-CD were found on the encapsulated compound demonstrated that most deposits were encapsulated with β-CD.

TNF-α blocker effect of naringenin-loaded sericin microparticles that are potentially useful in the treatment of psoriasis.

PubMed

Chlapanidas, Theodora; Perteghella, Sara; Leoni, Flavio; Faragò, Silvio; Marazzi, Mario; Rossi, Daniela; Martino, Emanuela; Gaggeri, Raffaella; Collina, Simona

2014-08-06

This study aims to evaluate the effect of combined use of the racemic flavanone Naringenin (NRG) and the protein sericin as TNF-α blockers. Sericin (SMs) and (R/S) NRG-loaded Sericin (SNRGMs) microparticles were prepared by spray-drying, characterized in terms of morphology and particle size distribution, and encapsulation efficiency was determined. Concerning morphology and particle size distribution of microparticles, results indicated that they were not affected by the presence of NRG. The encapsulation efficiency was almost quantitative (93%), thus proving that sericin can be advantageously loaded with (R/S) NRG. Biological evaluation of (R/S) NRG, SMs and SNRGMs was then performed in lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (hPBMC). SNRGMs resulted cytotoxic at the higher dose used (200 μg/mL) and the effect was greater than (R/S) NRG alone. Moreover, even if sericin alone was not effective in suppressing LPS-induced serum TNF-α levels, SNRGMs loaded with 9.3% of (R/S) NRG were significantly more potent than (R/S) NRG alone. In summary, this study provides the proof of concept that sericin-based microspheres loaded with TNF-α-blockers could contribute to the down regulation of the cytokine and represents the starting point for the development of new topical formulations for the treatment of middle-stage psoriasis.

TNF-α Blocker Effect of Naringenin-Loaded Sericin Microparticles that Are Potentially Useful in the Treatment of Psoriasis

PubMed Central

Chlapanidas, Theodora; Perteghella, Sara; Leoni, Flavio; Faragò, Silvio; Marazzi, Mario; Rossi, Daniela; Martino, Emanuela; Gaggeri, Raffaella; Collina, Simona

2014-01-01

This study aims to evaluate the effect of combined use of the racemic flavanone Naringenin (NRG) and the protein sericin as TNF-α blockers. Sericin (SMs) and (R/S) NRG-loaded Sericin (SNRGMs) microparticles were prepared by spray-drying, characterized in terms of morphology and particle size distribution, and encapsulation efficiency was determined. Concerning morphology and particle size distribution of microparticles, results indicated that they were not affected by the presence of NRG. The encapsulation efficiency was almost quantitative (93%), thus proving that sericin can be advantageously loaded with (R/S) NRG. Biological evaluation of (R/S) NRG, SMs and SNRGMs was then performed in lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (hPBMC). SNRGMs resulted cytotoxic at the higher dose used (200 μg/mL) and the effect was greater than (R/S) NRG alone. Moreover, even if sericin alone was not effective in suppressing LPS-induced serum TNF-α levels, SNRGMs loaded with 9.3% of (R/S) NRG were significantly more potent than (R/S) NRG alone. In summary, this study provides the proof of concept that sericin-based microspheres loaded with TNF-α-blockers could contribute to the down regulation of the cytokine and represents the starting point for the development of new topical formulations for the treatment of middle-stage psoriasis. PMID:25101847

Mucoadhesive Microparticles for Gastroretentive Delivery: Preparation, Biodistribution and Targeting Evaluation

PubMed Central

Hou, Jing-Yi; Gao, Li-Na; Meng, Fan-Yun; Cui, Yuan-Lu

2014-01-01

The aim of this research was to prepare and characterize alginate-chitosan mucoadhesive microparticles containing puerarin. The microparticles were prepared by an emulsification-internal gelatin method using a combination of chitosan and Ca2+ as cationic components and alginate as anions. Surface morphology, particle size, drug loading, encapsulation efficiency and swelling ratio, in vitro drug released, in vitro evaluation of mucoadhesiveness and Fluorescence imaging of the gastrointestinal tract were determined. After optimization of the formulation, the encapsulation efficiency was dramatically increased from 70.3% to 99.2%, and a highly swelling ratio was achieved with a change in particle size from 50.3 ± 11.2 μm to 124.7 ± 25.6 μm. In ethanol induced gastric ulcers, administration of puerarin mucoadhesive microparticles at doses of 150 mg/kg, 300 mg/kg, 450 mg/kg and 600 mg/kg body weight prior to ethanol ingestion significantly protected the stomach ulceration. Consequently, significant changes were observed in inflammatory cytokines, such as prostaglandin E2 (PGE2), tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and interleukin1β (IL-1β), in stomach tissues compared with the ethanol control group. In conclusion, core-shell type pH-sensitive mucoadhesive microparticles loaded with puerarin could enhance puerarin bioavailability and have the potential to alleviate ethanol-mediated gastric ulcers. PMID:25470180

Evaluation of the protective effects of curcuminoid (curcumin and bisdemethoxycurcumin)-loaded liposomes against bone turnover in a cell-based model of osteoarthritis.

PubMed

Yeh, Chih-Chang; Su, Yu-Han; Lin, Yu-Jhe; Chen, Pin-Jyun; Shi, Chung-Sheng; Chen, Cheng-Nan; Chang, Hsin-I

2015-01-01

Curcumin (Cur) and bisdemethoxycurcumin (BDMC), extracted from Curcuma longa, are poorly water-soluble polyphenol compounds that have shown anti-inflammatory potential for the treatment of osteoarthritis. To increase cellular uptake of Cur and BDMC in bone tissue, soybean phosphatidylcholines were used for liposome formulation. In this study, curcuminoid (Cur and BDMC)-loaded liposomes were characterized in terms of particle size, encapsulation efficiency, liposome stability, and cellular uptake. The results show that there is about 70% entrapment efficiency of Cur and BDMC in liposomes and that particle sizes are stable after liposome formation. Both types of liposome can inhibit macrophage inflammation and osteoclast differential activities. In comparison with free drugs (Cur and BDMC), curcuminoid-loaded liposomes were less cytotoxic and expressed high cellular uptake of the drugs. Of note is that Cur-loaded liposomes can prevent liposome-dependent inhibition of osteoblast differentiation and mineralization, but BDMC-loaded liposomes could not. With interleukin (IL)-1β stimulation, curcuminoid-loaded liposomes can successfully downregulate the expression of inflammatory markers on osteoblasts, and show a high osteoprotegerin (OPG)/receptor activator of nuclear factor κB ligand (RANKL) ratio to prevent osteoclastogenesis. In the present study, we demonstrated that Cur and BDMC can be successfully encapsulated in liposomes and can reduce osteoclast activity and maintain osteoblast functions. Therefore, curcuminoid-loaded liposomes may slow osteoarthritis progression.

Carbon-encapsulated cobalt nanoparticles: synthesis, properties, and magnetic particle hyperthermia efficiency

NASA Astrophysics Data System (ADS)

Kotoulas, A.; Dendrinou-Samara, C.; Sarafidis, C.; Kehagias, Th.; Arvanitidis, J.; Vourlias, G.; Angelakeris, M.; Kalogirou, Orestis

2017-12-01

A facile and low-cost method for structuring carbon-encapsulated cobalt nanoparticles (Co@C) is presented. Three samples were solvothermally prepared in one step at 220 °C and one in two steps at 200 °C. Three different polyols such as propylene glycol, triethylene glycol, and tetraethylene glycol were used as carbon sources, solvents, and reducing agents. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Concerning the crystal structure of the particles, a mixture of hcp/ fcc Co phases was obtained in three of the samples, independently of the polyol used. The coexistence of cubic and hexagonal phases was revealed both from XRD and high-resolution TEM (HRTEM). The formation of the cubic fcc structure, despite the relatively low reaction temperature, is attributed to the role of the interface between carbon coating and metallic core. The presence of carbon coating was demonstrated by Raman spectrometry, exhibiting the characteristic D and G graphitic bands, and by HRTEM observations. All samples showed ferromagnetic behavior with saturation magnetization up to 158 emu/g and coercivity up to 206 Oe. From the magnetic particle hyperthermia measurements recorded at a frequency of 765 kHz, a maximum SLP value of 241 W/g was obtained.

Synchronous microencapsulation of multiple components in silymarin into PLGA nanoparticles by an emulsification/solvent evaporation method.

PubMed

Xie, Yunchang; Yi, Yueneng; Hu, Xiongwei; Shangguan, Mingzhu; Wang, Lijuan; Lu, Yi; Qi, Jianping; Wu, Wei

2016-09-01

The development of polymeric carriers loaded with extracts suffers from the drawback not to be able to incorporate simultaneously various pharmacological compounds into the formulation. The aim of this study was therefore to achieve synchronous microencapsulation of multiple components of silymarin into poly (lactic-co-glycolic acid) nanoparticle, the most commonly used polymeric carrier with biodegradability and safety. The main strategy taken was to improve the overall entrapment efficiency and to reduce the escaping ratio of the components of different physicochemical properties. The optimized nanoparticles were spherical in morphology with a mean particle size of 150 ± 5 nm. Under common preparative conditions, silybin and isosilybin were entrapped in high efficiency, whereas taxifolin, silychristin and silydianin, especially taxifolin, showed less entrapment because they were more hydrophilic. By changing the pH of the outer aqueous phase and saturating it with silymarin, the entrapment efficiency of taxifolin, silychristin and silydianin could be significantly improved to over 90%, the level similar to silybin and isosilybin, thereby achieving synchronous encapsulation. It could be concluded that synchronous encapsulation of multiple components of silymarin was achieved by optimizing the preparative variables.

Effects of poly(lactic-co-glycolic acid) on preparation and characteristics of plasmid DNA-loaded solid lipid nanoparticles.

PubMed

Zhu, L; Xie, S; Dong, Z; Wang, X; Wang, Y; Zhou, W

2011-09-01

Poly(lactic-co-glycolic acid) (PLGA) was used as a polymeric emulsifier to encapsulate plasmid DNA into hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) by w/o/w double emulsion and solvent evaporation techniques. The effects of PLGA on the preparation, characteristics and transfection efficiency of DNA-loaded SLN were studied. The results showed that PLGA was essential to form the primary w/o emulsion and the stability of the emulsion was enhanced with the increase of PLGA content. DNA-loaded SLN were spherical with smooth surfaces. The SLN had a negative charge in weak acid and alkaline environment but acquired a positive charge in acidic pH and the cationisation capacity of the SLN increased with the increase of PLGA/HCO ratio. Agarose gel electrophoresis demonstrated that the majority of the DNA maintained its structural integrity after preparation and being extracted or released from DNA-loaded SLN. When PLGA/HCO ratio increased from 5 to 15%, the encapsulation efficiency, loading capacity and transfection efficiency of the nanoparticles increased significantly, whereas the changes of particle size and polydispersity index were insignificant. Cytotoxicity study in cell culture demonstrated that the SLN was not toxic.

Non-Covalent Microgel Particles Containing Functional Payloads: Coacervation of PEG-Based Triblocks via Microfluidics.

PubMed

Wang, Cynthia X; Utech, Stefanie; Gopez, Jeffrey D; Mabesoone, Mathijs F J; Hawker, Craig J; Klinger, Daniel

2016-07-06

Well-defined microgel particles were prepared by combining coacervate-driven cross-linking of ionic triblock copolymers with the ability to control particle size and encapsulate functional cargos inherent in microfluidic devices. In this approach, the efficient assembly of PEO-based triblock copolymers with oppositely charged end-blocks allows for bioinspired cross-linking under mild conditions in dispersed aqueous droplets. This strategy enables the integration of charged cargos into the coacervate domains (e.g., the loading of anionic model compounds through electrostatic association with cationic end-blocks). Distinct release profiles can be realized by systematically varying the chemical nature of the payload and the microgel dimensions. This mild and noncovalent assembly method represents a promising new approach to tunable microgels as scaffolds for colloidal biomaterials in therapeutics and regenerative medicine.

Formulation and in vitro characterization of protein-loaded liposomes

NASA Astrophysics Data System (ADS)

Kuzimski, Lauren

Background/Objective: Protein-based drugs are increasingly used to treat a variety of conditions including cancer and cardio-vascular disease. Due to the immune system's innate ability to degrade the foreign particles quickly, protein-based treatments are generally short-lived. To address this limitation, the objective of the study was to: 1) develop protein-loaded liposomes; 2) characterize size, stability, encapsulation efficiency and rate of protein release; and 3) determine intracellular uptake and distribution; and 4) protein structural changes. Method: Liposomes were loaded with a fluorescent-albumin using freeze-thaw (F/T) methodology. Albumin encapsulation and release were quantified by fluorescence spectroscopic techniques. Flow cytometry was used to determine liposome uptake by macrophages. Epifluorescence microscopy was used to determine cellular distribution of liposomes. Stability was determined using dynamic light scattering by measuring liposome size over one month period. Protein structure was determined using circular dichroism (CD). Result: Encapsulation of albumin in liposome was ˜90% and was dependent on F/T rates, with fifteen cycles yielding the highest encapsulation efficacy (p < 0.05). Albumin-loaded liposomes demonstrated consistent size (<300nm). Release of encapsulated albumin in physiological buffer at 25°C was ˜60% in 72 h. Fluorescence imaging suggested an endosomal route of cellular entry for the FITC-albumin liposome with maximum uptake rates in immune cells (30% at 2hour incubation). CD suggested protein structure is minimally impacted by freeze-thaw methodology. Conclusion: Using F/T as a loading method, we were able to successfully achieve a protein-loaded liposome that was under 300nm, had encapsulation of ˜90%. Synthesized liposomes demonstrated a burst release of encapsulate protein (60%) at 72 hours. Cellular trafficking confirmed endosomal uptake, and minimal protein damage was noticed in CD.

Bioactive Encapsulation for Military Food Applications: Request for Enhanced Nano and Micro Particle Fabrication and Characterization Facilities

DTIC Science & Technology

2016-01-25

2013 21-Jul-2014 Approved for Public Release; Distribution Unlimited Final Report: Bioactive Encapsulation for Military Food Applications: Request for...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: Bioactive Encapsulation for Military Food Applications...Total Number: ...... Inventions (DD882) Scientific Progress Equipment was purchased. Technology Transfer 1 Bioactive Encapsulation for Military Food

Preparation, characterization and stability of curcumin-loaded zein-shellac composite colloidal particles.

PubMed

Sun, Cuixia; Xu, Chenqi; Mao, Like; Wang, Di; Yang, Jie; Gao, Yanxiang

2017-08-01

Curcumin-loaded zein-shellac composite particles were prepared by the antisolvent co-precipitation method. The encapsulation efficiency of curcumin was significantly improved from 82.7% in zein particles to 93.2% in zein-shellac complex particles. The result of differential scanning calorimetry suggested that curcumin in the polymeric matrix was in an amorphous state. Fourier transform infrared spectroscopy analysis revealed that curcumin had non-covalently interacted with zein and shellac, mainly through hydrogen bonding and hydrophobic interaction. Aggregates in irregular shapes, with large sizes, were found by atomic force microscopy, and conglutination, integration or fusion of different entities into network structures occurred at a high level of shellac. At the mass ratio of zein to shellac of 1:1, curcumin in the complex particles exhibited improved photochemical and thermal stability. Curcumin-loaded zein-shellac complex particles allowed the controlled release of curcumin in both PBS medium and simulated gastrointestinal fluids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Designing biopolymer microgels to encapsulate, protect and deliver bioactive components: Physicochemical aspects.

PubMed

McClements, David Julian

2017-02-01

Biopolymer microgels have considerable potential for their ability to encapsulate, protect, and release bioactive components. Biopolymer microgels are small particles (typically 100nm to 1000μm) whose interior consists of a three-dimensional network of cross-linked biopolymer molecules that traps a considerable amount of solvent. This type of particle is also sometimes referred to as a nanogel, hydrogel bead, biopolymer particles, or microsphere. Biopolymer microgels are typically prepared using a two-step process involving particle formation and particle gelation. This article reviews the major constituents and fabrication methods that can be used to prepare microgels, highlighting their advantages and disadvantages. It then provides an overview of the most important characteristics of microgel particles (such as size, shape, structure, composition, and electrical properties), and describes how these parameters can be manipulated to control the physicochemical properties and functional attributes of microgel suspensions (such as appearance, stability, rheology, and release profiles). Finally, recent examples of the utilization of biopolymer microgels to encapsulate, protect, or release bioactive agents, such as pharmaceuticals, nutraceuticals, enzymes, flavors, and probiotics is given. Copyright © 2016 Elsevier B.V. All rights reserved.

Microencapsulation by Membrane Emulsification of Biophenols Recovered from Olive Mill Wastewaters

PubMed Central

Piacentini, Emma; Poerio, Teresa; Bazzarelli, Fabio; Giorno, Lidietta

2016-01-01

Biophenols are highly prized for their free radical scavenging and antioxidant activities. Olive mill wastewaters (OMWWs) are rich in biophenols. For this reason, there is a growing interest in the recovery and valorization of these compounds. Applications for the encapsulation have increased in the food industry as well as the pharmaceutical and cosmetic fields, among others. Advancements in micro-fabrication methods are needed to design new functional particles with target properties in terms of size, size distribution, and functional activity. This paper describes the use of the membrane emulsification method for the fine-tuning of microparticle production with biofunctional activity. In particular, in this pioneering work, membrane emulsification has been used as an advanced method for biophenols encapsulation. Catechol has been used as a biophenol model, while a biophenols mixture recovered from OMWWs were used as a real matrix. Water-in-oil emulsions with droplet sizes approximately 2.3 times the membrane pore diameter, a distribution span of 0.33, and high encapsulation efficiency (98% ± 1% and 92% ± 3%, for catechol and biophenols, respectively) were produced. The release of biophenols was also investigated. PMID:27171115

Microencapsulation of betalains obtained from cactus fruit (Opuntia ficus-indica) by spray drying using cactus cladode mucilage and maltodextrin as encapsulating agents.

PubMed

Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Nazareno, Mónica Azucena; Osorio, Coralia

2015-11-15

The microencapsulation of betalains from cactus fruit by spray drying was evaluated as a stabilization strategy for these pigments. The betalains used as active agent were extracted from purple fruits of Opuntia ficus-indica (BE) and encapsulated with maltodextrin and cladode mucilage MD-CM and only with MD. The microcapsulates were characterized by scanning electron microscopy (SEM), thermal analysis (TGA-DSC), tristimulus colorimetry, as well as, their humidity, water activity and dietary fiber content were also determined. The active agent content was measured by UV-Vis spectrophotometry and its composition confirmed by HPLC-ESIMS. A pigment storage stability test was performed at 18 °C and different relative humidities. The addition of CM in the formulation increased the encapsulation efficiency, diminished the moisture content, and allowed to obtain more uniform size and spherical particles, with high dietary fiber content. These microencapsulates are promising functional additive to be used as natural colorant in the food industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of liposomal encapsulation on degradation of anthocyanins of black carrot extract by adding ascorbic acid.

PubMed

Guldiken, Burcu; Gibis, Monika; Boyacioglu, Dilek; Capanoglu, Esra; Weiss, Jochen

2017-03-22

Black carrot anthocyanins are known to be relatively stable because they contain acylated anthocyanins. The degradation of vitamin C (l-ascorbic acid) on anthocyanins is a known fact in beverage systems. In this study, the effects of various liposomal systems, including black carrot extract (0.1%, 0.2%, 0.4% w/w) and lecithin (1%, 2%, 4% w/w), on the color and degradation of anthocyanin in different ascorbic acid (0.01%, 0.025%, 0.05%, 0.1% w/w) concentrations were examined via UV/VIS spectroscopy and visual control of the color. The physical characteristics of the liposomal systems resulted in particle diameters of 41-46 nm and zeta-potentials of (-23)-(-20) mV. The encapsulation efficiencies of the liposomal systems increased up to 50% with increasing lecithin concentrations. The encapsulation of black carrot extract in liposomes enhanced the color and stability of the anthocyanins during storage. This study showed that the degradation of anthocyanins due to ascorbic acid can be reduced by liposomes in aqueous solutions.

Evaluation of hypericin-loaded solid lipid nanoparticles: physicochemical properties, photostability and phototoxicity.

PubMed

Youssef, Tareq; Fadel, Maha; Fahmy, Rania; Kassab, Kawser

2012-01-01

Hypericin (HYP), a natural photosensitizer, has powerful photo-oxidizing ability, tumor-seeking characteristics, and minimal dark toxicity; nevertheless, it has proven high lipid solubility compared to its sparingly water soluble nature. Therefore, its formulation into solid lipid nanoparticles (SLNs) has attracted increasing attention as a potential drug-delivery carrier. Two HYP-loaded SLNs formulations were prepared utilizing microemulsion-based technique. Thereafter, the physicochemical properties of the formulations were investigated and evaluated. HYP-loaded SLNs showed spherical shape with mean particle size ranging from 200-300 nm for both formulations (FA and FB). The encapsulation efficiencies reached above 80% and FA showed significant higher encapsulation than FB (P<0.05), also, the thermal analysis using differential scanning calorimetry (DSC) indicated good compatibility between hypericin and lipids forming the cores in both formulations. Spectroscopic measurements of the photostability study showed that hypericin encapsulation into SLNs improved its photostability, compared to free HYP in 0.1% ethanolic solution. However, photocytotoxicity studies on HepG2 cells revealed an evident inhibition of the photodynamic efficacy of HYP-loaded SLNs, compared to free HYP. In conclusion, although the elevated entrapment efficiency of HYP into SLNs increased its photostability, it decreased its phototoxicity which might be due to the quenching deactivation of HYP molecules resulting from SLN compactness and thickness structure. © 2012 Informa Healthcare USA, Inc.

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

PubMed Central

Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

2014-01-01

A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. PMID:24855351

Formulation for Oral Delivery of Lactoferrin Based on Bovine Serum Albumin and Tannic Acid Multilayer Microcapsules

NASA Astrophysics Data System (ADS)

Kilic, Ece; Novoselova, Marina V.; Lim, Su Hui; Pyataev, Nikolay A.; Pinyaev, Sergey I.; Kulikov, Oleg A.; Sindeeva, Olga A.; Mayorova, Oksana A.; Murney, Regan; Antipina, Maria N.; Haigh, Brendan; Sukhorukov, Gleb B.; Kiryukhin, Maxim V.

2017-03-01

Lactoferrin (Lf) has considerable potential as a functional ingredient in food, cosmetic and pharmaceutical applications. However, the bioavailability of Lf is limited as it is susceptible to digestive enzymes in gastrointestinal tract. The shells comprising alternate layers of bovine serum albumin (BSA) and tannic acid (TA) were tested as Lf encapsulation system for oral administration. Lf absorption by freshly prepared porous 3 μm CaCO3 particles followed by Layer-by-Layer assembly of the BSA-TA shells and dissolution of the CaCO3 cores was suggested as the most efficient and harmless Lf loading method. The microcapsules showed high stability in gastric conditions and effectively protected encapsulated proteins from digestion. Protective efficiency was found to be 76 ± 6% and 85 ± 2%, for (BSA-TA)4 and (BSA-TA)8 shells, respectively. The transit of Lf along the gastrointestinal tract (GIT) of mice was followed in vivo and ex vivo using NIR luminescence. We have demonstrated that microcapsules released Lf in small intestine allowing 6.5 times higher concentration than in control group dosed with the same amount of free Lf. Significant amounts of Lf released from microcapsules were then absorbed into bloodstream and accumulated in liver. Suggested encapsulation system has a great potential for functional foods providing lactoferrin.

Cytotoxicity of solid lipid nanoparticles and nanostructured lipid carriers containing the local anesthetic dibucaine designed for topical application

NASA Astrophysics Data System (ADS)

Barbosa, R. M.; da Silva, C. M. G.; Bella, T. S.; de Araújo, D. R.; Marcato, P. D.; Durán, N.; de Paula, E.

2013-04-01

Dibucaine (DBC) is powerful long-lasting local anesthetic, but it is also considered fairly toxic to the CNS. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have attracted attention as carriers for drug delivery. The aim of this study was to develop and to evaluate the cytotoxic activity of DBC-loaded SLN and NLC against 3T3 fibroblast and HaCat keratinocyte cells. The SLN and NLC had myristyl myristate and Liponate®GC as their lipid matrices, respectively, plus a surfactant. SLN and NLC were characterized in terms in their diameter, size distribution, surface charge and DBC encapsulation efficiency. The particle size of SLN and NLC were around 234.33 and 166.62 nm, respectively. The polydispersity index was kept below 0.2 for both nanomaterials. Negative surface charges were observed for both nanoparticles, which decreased in the presence of the anesthetic. Encapsulation efficiency reached 76% and 90%, respectively, in SLN and NLC. DBC alone was found to be toxic to 3T3 and HaCat cells in culture. However, NLC and SLN loaded DBC decreased its intrinsic cytotoxic effect against 3T3 and HaCat cells. In conclusion, encapsulation of DBC in SLN and NLC decreased the in vitro toxicity of the local anesthetic, indicating the potential of these nanocarriers for clinical applications.

In-vitro studies of enteric coated diclofenac sodium-carboxymethylcellulose microspheres.

PubMed

Arica, B; Arica, M Y; Kaş, H S; Hincal, A A; Hasirci, V

1996-01-01

MIcrospheres containing diclofenac sodium (DS) were prepared using carboxymethylcellulose (CMC) as the main support material (1.0, 2.0, 3.0% (w/v)) and aluminum chloride as the crosslinker. Drug to polymer ratios of 1:1, 1:2 and 1:4 were used to obtain a range of microspheres. The microspheres were then coated with an enteric coating material, Eudragit S-100, efficiency, % yield value, particle sizes an in-vitro dissolution behaviour were investigated. The surface of the enteric coated microspheres seemed to be all covered with Eudragit S-100 from scanning electron microscopy observation. It was also observed that increasing the CMC concentration led to an increase in the encapsulation efficiency, % yield value and particle size and decreased the release rate. Eudragit S-100 coating did not significantly alter the size but the release rate was significantly lower even when the lower concentration solution was used.

Microfluidic Devices for Drug Delivery Systems and Drug Screening

PubMed Central

Kompella, Uday B.; Damiati, Safa A.

2018-01-01

Microfluidic devices present unique advantages for the development of efficient drug carrier particles, cell-free protein synthesis systems, and rapid techniques for direct drug screening. Compared to bulk methods, by efficiently controlling the geometries of the fabricated chip and the flow rates of multiphase fluids, microfluidic technology enables the generation of highly stable, uniform, monodispersed particles with higher encapsulation efficiency. Since the existing preclinical models are inefficient drug screens for predicting clinical outcomes, microfluidic platforms might offer a more rapid and cost-effective alternative. Compared to 2D cell culture systems and in vivo animal models, microfluidic 3D platforms mimic the in vivo cell systems in a simple, inexpensive manner, which allows high throughput and multiplexed drug screening at the cell, organ, and whole-body levels. In this review, the generation of appropriate drug or gene carriers including different particle types using different configurations of microfluidic devices is highlighted. Additionally, this paper discusses the emergence of fabricated microfluidic cell-free protein synthesis systems for potential use at point of care as well as cell-, organ-, and human-on-a-chip models as smart, sensitive, and reproducible platforms, allowing the investigation of the effects of drugs under conditions imitating the biological system. PMID:29462948

Formulation, characterization and cytotoxicity studies of alendronate sodium-loaded solid lipid nanoparticles.

PubMed

Ezzati Nazhad Dolatabadi, Jafar; Hamishehkar, Hamed; Eskandani, Morteza; Valizadeh, Hadi

2014-05-01

Solid lipid nanoparticles (SLNs) are novel drug delivery system for drug targeting in various routs of administration such as parenteral, oral, ophthalmic and topical. These carriers have some advantages such as high drug payload, increased drug stability, the possibility of incorporation of lipophilic and hydrophilic drugs, and low biotoxicity. In this study, alendronate sodium was used as a hydrophilic model drug and was incorporated into SLNs. Hot homogenization method was used for preparation of alendronate sodium-loaded SLN formulations and the encapsulation efficiency of drug in SLNs was determined by ultrafiltration method using centrifugal devices. Scanning electron microscopy (SEM) was carried out to study the morphological behaviors of prepared SLNs like sphericity. Several cytotoxicity studies including MTT, DAPI staining and DNA fragmentation assays were used for biocompatibility assays. High drug encapsulation efficiency (70-85%) was achieved by drug determination through derivatization with o-phthalaldehyde. The physical stability of drug-loaded SLNs in aqueous dispersions was assessed in terms of size and drug leakage during two weeks. Scanning electron microscopy images showed spherical particles in the nanometer range confirming the obtained data from size analyzer. Several cytotoxicity studies including MTT, DAPI staining and DNA fragmentation assays as well as flow cytometry analysis confirmed the low toxicity of alendronate-loaded SLNs. The cost-efficient procedure, the avoidance of organic solvents application, acceptable reproducibility, ease of manufacturing under mild preparation conditions, high level of drug encapsulation, desirable physical stability and biocompatibility are the advantages of the proposed SLN formulations. Copyright © 2014 Elsevier B.V. All rights reserved.

Risk management and statistical multivariate analysis approach for design and optimization of satranidazole nanoparticles.

PubMed

Dhat, Shalaka; Pund, Swati; Kokare, Chandrakant; Sharma, Pankaj; Shrivastava, Birendra

2017-01-01

Rapidly evolving technical and regulatory landscapes of the pharmaceutical product development necessitates risk management with application of multivariate analysis using Process Analytical Technology (PAT) and Quality by Design (QbD). Poorly soluble, high dose drug, Satranidazole was optimally nanoprecipitated (SAT-NP) employing principles of Formulation by Design (FbD). The potential risk factors influencing the critical quality attributes (CQA) of SAT-NP were identified using Ishikawa diagram. Plackett-Burman screening design was adopted to screen the eight critical formulation and process parameters influencing the mean particle size, zeta potential and dissolution efficiency at 30min in pH7.4 dissolution medium. Pareto charts (individual and cumulative) revealed three most critical factors influencing CQA of SAT-NP viz. aqueous stabilizer (Polyvinyl alcohol), release modifier (Eudragit® S 100) and volume of aqueous phase. The levels of these three critical formulation attributes were optimized by FbD within established design space to minimize mean particle size, poly dispersity index, and maximize encapsulation efficiency of SAT-NP. Lenth's and Bayesian analysis along with mathematical modeling of results allowed identification and quantification of critical formulation attributes significantly active on the selected CQAs. The optimized SAT-NP exhibited mean particle size; 216nm, polydispersity index; 0.250, zeta potential; -3.75mV and encapsulation efficiency; 78.3%. The product was lyophilized using mannitol to form readily redispersible powder. X-ray diffraction analysis confirmed the conversion of crystalline SAT to amorphous form. In vitro release of SAT-NP in gradually pH changing media showed <20% release in pH1.2 and pH6.8 in 5h, while, complete release (>95%) in pH7.4 in next 3h, indicative of burst release after a lag time. This investigation demonstrated effective application of risk management and QbD tools in developing site-specific release SAT-NP by nanoprecipitation. Copyright © 2016 Elsevier B.V. All rights reserved.

Color, bioactive compounds and morphological characteristics of encapsulated Asian pear juice powder during spray drying.

PubMed

Lee, Chang-Gon; Ahmed, Maruf; Jiang, Gui-Hun; Eun, Jong-Bang

2017-08-01

Encapsulated Asian pear juice powder was produced through spray drying using three maltodextrin levels (15, 20, and 25% w/v) and three inlet air temperatures (130, 150, and 170 °C). The impact of maltodextrin concentrations and inlet air temperatures on color, bioactive compounds, and morphological characteristics of encapsulated Asian pear juice powder were investigated. Maltodextrin concentrations and inlet air temperatures significantly influenced L * and b * values of encapsulated Asian pear juice powder. Increasing inlet air temperatures increased total phenolic content, whereas the vitamin C content decreased. Vitamin C content was strongly correlated with particle size, inlet air temperature, and maltodextrin concentration. ABTS + radical-scavenging activity was highly correlated with total phenol content while DPPH radical-scavenging activity was highly correlated with vitamin C content. Encapsulated powders made with higher inlet air temperature and higher maltodextrin concentration had lowest median particle diameter with a smoother, more regular and rounded outer surface than those of encapsulated powders produced with lower inlet air temperature and lower maltodextrin concentration. Therefore, the results demonstrate that high-quality encapsulated Asian pear juice powder could be manufactured by adding 15% (w/v) maltodextrin and spray-drying at 170 °C.

Aerosolized Antimicrobial Agents Based on Degradable Dextran Nanoparticles Loaded with Silver Carbene Complexes

PubMed Central

Ornelas-Megiatto, Cátia; Shah, Parth N.; Wich, Peter R.; Cohen, Jessica L.; Tagaev, Jasur A.; Smolen, Justin A.; Wright, Brian D.; Panzner, Matthew J.; Youngs, Wiley J.; Fréchet, Jean M. J.; Cannon, Carolyn L.

2012-01-01

Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH2Cl2 (organic): PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery. PMID:23025592

Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes.

PubMed

Ornelas-Megiatto, Cátia; Shah, Parth N; Wich, Peter R; Cohen, Jessica L; Tagaev, Jasur A; Smolen, Justin A; Wright, Brian D; Panzner, Matthew J; Youngs, Wiley J; Fréchet, Jean M J; Cannon, Carolyn L

2012-11-05

Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH(2)Cl(2) (organic):PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery.

Microchannel emulsification: A promising technique towards encapsulation of functional compounds.

PubMed

Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi

2017-06-13

This review provides an overview of microchannel emulsification (MCE) for production of functional monodispersed emulsion droplets. The main emphasis has been put on functional bioactives encapsulation using grooved-type and straight-through microchannel array plates. MCE successfully encapsulates the bioactives like β-carotene, oleuropein, γ-oryzanol, β-sitosterol, L-ascorbic acid and ascorbic acid derivatives, vitamin D and quercetin. These bioactives were encapsulated in a variety of delivery systems like simple and multiple emulsions, polymeric particles, microgels, solid lipid particles and functional vesicles. The droplet generation process in MCE is based upon spontaneous transformation of interfaces rather than high energy shear stress systems. The scale-up of MCE can increase the productivity of monodispersed droplets >100 L h -1 and makes it a promising tool at industrial level.

Microfluidic-Based Generation of Size-Controlled, Biofunctionalized Synthetic Polymer Microgels for Cell Encapsulation

PubMed Central

Headen, Devon M.; Aubry, Guillaume; Lu, Hang

2014-01-01

Cell and islet microencapsulation in synthetic hydrogels provide an immunoprotective and cell-supportive microenvironment. A microfluidic strategy for the genaration of biofunctionalized, synthetic microgel particles with precise control over particle size and molecular permeability for cell and protein delivery is presented. These engineered capsules support high cell viability and function of encapsulated human stem cells and islets. PMID:24615922

Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery.

PubMed

Gonzalez-Mira, E; Egea, M A; Souto, E B; Calpena, A C; García, M L

2011-01-28

The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol(®) 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween(®) 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (∼90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.

Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery

NASA Astrophysics Data System (ADS)

Gonzalez-Mira, E.; Egea, M. A.; Souto, E. B.; Calpena, A. C.; García, M. L.

2011-01-01

The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol® 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween® 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (~90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.

Graphene Caging Silicon Particles for High-Performance Lithium-Ion Batteries.

PubMed

Nie, Ping; Le, Zaiyuan; Chen, Gen; Liu, Dan; Liu, Xiaoyan; Wu, Hao Bin; Xu, Pengcheng; Li, Xinru; Liu, Fang; Chang, Limin; Zhang, Xiaogang; Lu, Yunfeng

2018-06-01

Silicon holds great promise as an anode material for lithium-ion batteries with higher energy density; its implication, however, is limited by rapid capacity fading. A catalytic growth of graphene cages on composite particles of magnesium oxide and silicon, which are made by magnesiothermic reduction reaction of silica particles, is reported herein. Catalyzed by the magnesium oxide, graphene cages can be conformally grown onto the composite particles, leading to the formation of hollow graphene-encapsulated Si particles. Such materials exhibit excellent lithium storage properties in terms of high specific capacity, remarkable rate capability (890 mAh g -1 at 5 A g -1 ), and good cycling retention over 200 cycles with consistently high coulombic efficiency at a current density of 1 A g -1 . A full battery test using LiCoO 2 as the cathode demonstrates a high energy density of 329 Wh kg -1 . © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wax encapsulation of water-soluble compounds for application in foods.

PubMed

Mellema, M; Van Benthum, W A J; Boer, B; Von Harras, J; Visser, A

2006-11-01

Water-soluble ingredients have been successfully encapsulated in wax using two preparation techniques. The first technique ('solid preparation') leads to relatively large wax particles. The second technique ('liquid preparation') leads to relatively small wax particles immersed in vegetable oil. On the first technique: stable encapsulation of water-soluble colourants (dissolved at low concentration in water) has been achieved making use of beeswax and PGPR. The leakage from the capsules, for instance of size 2 mm, is about 30% after 16 weeks storage in water at room temperature. To form such capsules a minimum wax mass of 40% relative to the total mass is needed. High amounts of salt or acids at the inside water phase causes more leaking, probably because of the osmotic pressure difference. Osmotic matching of inner and outer phase can lead to a dramatic reduction in leakage. Fat capsules are less suitable to incorporate water soluble colourants. The reason for this could be a difference in crystal structure (fat is less ductile and more brittle). On the second technique: stable encapsulation of water-soluble colourants (encapsulated in solid wax particles) has been achieved making use of carnauba wax. The leakage from the capsules, for instance of size 250 mm, is about 40% after 1 weeks storage in water at room temperature.

Physical and biological characterization of sericin-loaded copolymer liposomes stabilized by polyvinyl alcohol.

PubMed

Suktham, Kunat; Koobkokkruad, Thongchai; Saesoo, Somsak; Saengkrit, Nattika; Surassmo, Suvimol

2016-12-01

Sericin protein (SP) is widely used as a nutrient biomaterial for biomedical and cosmeceutical applications although it shows low stability to heat and light. To overcome these problems and add value to wastewater from the silk industry, sericin protein was recovered as sericin-loaded copolymer-liposomes (SP-PVA-LP), prepared through thin film hydration. The size and morphology of the liposomes were investigated using dynamic light scattering (DLS), and electron microscopy (SEM and TEM). The particle size, liposome surface morphology and encapsulation efficiency of SP were dependent on PVA concentration. The hydrodynamic size of the nanoparticles was between 200 and 400nm, with the degree of negative charge contingent on sericin loading. SEM and TEM images confirmed the mono-dispersity, and spherical nature of the particles, with FTIR measurements confirming the presence of surface bound PVA. Exposure of liposomes to 500ppm sericin highlighted a dependence of encapsulation efficiency on PVA content; 2% surface PVA proved the optimal level for sericin loading. Cytotoxicity and viability assays revealed that SP-loaded surface modified liposomes promote cellular attachment and proliferation of human skin fibroblasts without adverse toxic effects. Surface modified copolymer liposomes show high performance in maintaining structural stability, and promoting enhancements in the solubility and bio-viability of sericin. Taken together, these biocompatible constructs allow for effective controlled release, augmenting sericin activity and resulting in effective drug delivery systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation, characterization and cytotoxic evaluation of bovine serum albumin nanoparticles encapsulating 5-methylmellein: A secondary metabolite isolated from Xylaria psidii.

PubMed

Arora, Divya; Kumar, Amit; Gupta, Prasoon; Chashoo, Gousia; Jaglan, Sundeep

2017-12-01

In this study, 5-methylmellein (5-MM) loaded bovine serum albumin nanoparticles (BSA NPs) were developed using desolvation technique. The developed nanoparticles were characterized for their mean particle size, polydispersity, zeta potential, loading efficiency, X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and release profile. The developed nanoparticles were spherical in shape under transmission electron microscopy (TEM) and atomic force microscopy (AFM). The developed 5-MM loaded BSA NPs demonstrated a mean particle size with a diameter of 154.95 ± 4.44 nm. The results from XRD and DSC studies demonstrated that the crystal state of the 5-MM was converted to an amorphous state in polymeric matrix. The encapsulation and loading efficiency was found to be 73.26 ± 4.48% and 7.09 ± 0.43%. The in vitro cytotoxicity in human prostate cancer cell line (PC-3), human colon cancer cells (HCT-116) and human breast adenocarcinoma cell line (MCF-7) cells demonstrated enhanced cytotoxicity of 5-MM BSA NPs as compared to native 5-MM after 72-h treatment. The enhancement in cytotoxicity of 5-MM BSA NPs was also supported by increase in cellular apoptosis, mitochondrial membrane potential loss and generation of high reactive oxygen species (ROS). In conclusion, these findings collectively indicated that BSA nanoparticles may serve as promising drug delivery system for improving the efficacy of 5-methylmellein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brain targeted nanoparticulate drug delivery system of rasagiline via intranasal route.

PubMed

Mittal, Deepti; Md, Shadab; Hasan, Quamrul; Fazil, Mohammad; Ali, Asgar; Baboota, Sanjula; Ali, Javed

2016-01-01

The aim of the present study was to prepare and evaluate a rasagiline-loaded chitosan glutamate nanoparticles (RAS-CG-NPs) by ionic gelation of CG with tripolyphosphate anions (TPP). RAS-loaded CG-NPs were characterized for particle size, size distribution, encapsulation efficiency and in vitro drug release. The mean particles size, polydispersity index (PDI) and encapsulation efficiency was found to be 151.1 ± 10.31, 0.380 ± 0.01 and 96.43 ± 4.23, respectively. Biodistribution of RAS formulations in the brain and blood of mice following intranasal (i.n.) and intravenous (i.v.) administration was performed using HPLC analytical method. The drug concentrations in brain following the i.n. of CG-NPs were found to be significantly higher at all the time points compared to both drug (i.n.) and drug CG-NPs (i.v.). The Cmax (999.25 ng/ml) and AUC (2086.60 ng h/ml) of formulation CG-NPs (i.n) were found to be significantly higher than CG-NPs (i.v.) and RAS solution (i.n.). The direct transport percentage (DTP%) values of RAS-loaded CG-NPs (i.n.) as compared to drug solution (i.n.) increased from 66.27 ± 1.8 to 69.27 ± 2.1%. The results showed significant enhancement of bioavailability in brain, after administration of the RAS-loaded CG-NPs which could be a substantial achievement of direct nose to brain targeting in Parkinson's disease therapy.

Synthesis of silica-PAMAM dendrimer nanoparticles as promising carriers in Neuro blastoma cells.

PubMed

Yesil-Celiktas, Ozlem; Pala, Cansu; Cetin-Uyanikgil, E Oyku; Sevimli-Gur, Canan

2017-02-15

Mesoporous silica carriers are emerging as therapeutic drug delivery systems. The objective of this study was to develop a formulation for synthesizing silica-PAMAM dendrimer hybrid nanoparticles with sol-gel technique. Subsequently, black carrot anthocyanins were encapsulated and investigated for their capability in terms of inhibiting the proliferative effects of neuroblastoma (Neuro 2A). In this context, particle size distributions were ascertained followed by thermal analysis (DSC), scanning electron microscopy and encapsulation efficiency. Subsequently, in vitro release kinetics was determined along with cytotoxicity of empty and anthocyanin doped hybrid nanoparticles. The lowest particle size was 134.8 nm with a zeta potential of +19.78 mV which enhanced electrostatic interaction with the cell membrane in the cytotoxicity analyses. As the anthocyanin content was totally released at the end of 6 days, the cytotoxicity was observed for 134 h, reaching an inhibition of 87.9%. On the other hand, Neuro 2A cells incubated with empty nanoparticles exhibited a high proliferation indicating that hybrid nanoparticles were not toxic to the cells and the inhibitory effect was associated with the anthocyanins. Copyright © 2016 Elsevier Inc. All rights reserved.

Interaction of colistin and colistin methanesulfonate with liposomes: colloidal aspects and implications for formulation.

PubMed

Wallace, Stephanie J; Li, Jian; Nation, Roger L; Prankerd, Richard J; Boyd, Ben J

2012-09-01

Interaction of colistin and colistin methanesulfonate (CMS) with liposomes has been studied with the view to understanding the limitations to the use of liposomes as a more effective delivery system for pulmonary inhalation of this important class of antibiotic. Thus, in this study, liposomes containing colistin or CMS were prepared and characterized with respect to colloidal behavior and drug encapsulation and release. Association of anionic CMS with liposomes induced negative charge on the particles. However, degradation of the CMS to form cationic colistin over time was directly correlated with charge reversal and particle aggregation. The rate of degradation of CMS was significantly more rapid when associated with the liposome bilayer than when compared with the same concentration in aqueous solution. Colistin liposomes carried positive charge and were stable. Encapsulation efficiency for colistin was approximately 50%, decreasing with increasing concentration of colistin. Colistin was rapidly released from liposomes on dilution. Although the studies indicate limited utility of colistin or CMS liposomes for long duration controlled-release applications, colistin liposomes were highly stable and may present a potential opportunity for coformulation of colistin with a second antibiotic to colocalize the two drugs after pulmonary delivery. Copyright © 2012 Wiley Periodicals, Inc.

Interaction of Colistin and Colistin Methanesulfonate with Liposomes: Colloidal Aspects and Implications for Formulation

PubMed Central

WALLACE, STEPHANIE J.; LI, JIAN; NATION, ROGER L.; PRANKERD, RICHARD J.; BOYD, BEN J.

2012-01-01

Interaction of colistin and colistin methanesulfonate (CMS) with liposomes has been studied with the view to understanding the limitations to the use of liposomes as a more effective delivery system for pulmonary inhalation of this important class of antibiotic. Thus, in this study, liposomes containing colistin or CMS were prepared and characterized with respect to colloidal behavior and drug encapsulation and release. Association of anionic CMS with liposomes induced negative charge on the particles. However, degradation of the CMS to form cationic colistin over time was directly correlated with charge reversal and particle aggregation. The rate of degradation of CMS was significantly more rapid when associated with the liposome bilayer than when compared with the same concentration in aqueous solution. Colistin liposomes carried positive charge and were stable. Encapsulation efficiency for colistin was approximately 50%, decreasing with increasing concentration of colistin. Colistin was rapidly released from liposomes on dilution. Although the studies indicate limited utility of colistin or CMS liposomes for long duration controlled-release applications, colistin liposomes were highly stable and may present a potential opportunity for coformulation of colistin with a second antibiotic to colocalize the two drugs after pulmonary delivery. PMID:22623044

Preservation of anthocyanins in solid lipid nanoparticles: Optimization of a microemulsion dilution method using the Placket-Burman and Box-Behnken designs.

PubMed

Ravanfar, Raheleh; Tamaddon, Ali Mohammad; Niakousari, Mehrdad; Moein, Mahmoud Reza

2016-05-15

Anthocyanins are the main polyphenol components from red cabbage (Brassica oleracea L. Var. Capitata f. Rubra) extracts that have inherent antioxidant activities. Anthocyanins are effectively stable in acidic gastric digestion conditions, with nearly 100% phenol content recovery. However, the total phenol content recovery after simulated pancreatic digestion was approximately 25%. To protect anthocyanins against harsh environmental conditions (e.g., pH and temperature), solid lipid nanoparticles were prepared by the dilution of water in oil (w/o) microemulsions containing anthocyanins in aqueous media. The formulations were characterized for particle size and encapsulation efficiency. The formulation parameters (e.g., volume of the internal aqueous phase, homogenization time and the percentages of total lipid, total surfactant or stabilizer) were optimized using the Placket-Burman and Box-Behnken experimental designs. Entrapment efficiency (89.2 ± 0.3%) was calculated when the mean particle size was 455 ± 2 nm. A scanning electron microscopy study revealed the spherical morphology of the particles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative studies on osmosis based encapsulation of sodium diclofenac in porcine and outdated human erythrocyte ghosts.

PubMed

Bukara, Katarina; Drvenica, Ivana; Ilić, Vesna; Stančić, Ana; Mišić, Danijela; Vasić, Borislav; Gajić, Radoš; Vučetić, Dušan; Kiekens, Filip; Bugarski, Branko

2016-12-20

The objective of our study was to develop controlled drug delivery system based on erythrocyte ghosts for amphiphilic compound sodium diclofenac considering the differences between erythrocytes derived from two readily available materials - porcine slaughterhouse and outdated transfusion human blood. Starting erythrocytes, empty erythrocyte ghosts and diclofenac loaded ghosts were compared in terms of the encapsulation efficiency, drug releasing profiles, size distribution, surface charge, conductivity, surface roughness and morphology. The encapsulation of sodium diclofenac was performed by an osmosis based process - gradual hemolysis. During this process sodium diclofenac exerted mild and delayed antihemolytic effect and increased potassium efflux in porcine but not in outdated human erythrocytes. FTIR spectra revealed lack of any membrane lipid disorder and chemical reaction with sodium diclofenac in encapsulated ghosts. Outdated human erythrocyte ghosts with detected nanoscale damages and reduced ability to shrink had encapsulation efficiency of only 8%. On the other hand, porcine erythrocyte ghosts had encapsulation efficiency of 37% and relatively slow drug release rate. More preserved structure and functional properties of porcine erythrocytes related to their superior encapsulation and release performances, define them as more appropriate for the usage in sodium diclofenac encapsulation process. Copyright © 2016 Elsevier B.V. All rights reserved.

Design, characterisation and application of alginate-based encapsulated pig liver esterase.

PubMed

Pauly, Jan; Gröger, Harald; Patel, Anant V

2018-06-05

Encapsulation of hydrolases in biopolymer-based hydrogels often suffers from low activities and encapsulation efficiencies along with high leaching and unsatisfactory recycling properties. Exemplified for the encapsulation of pig liver esterase the coating of alginate and chitosan beads have been studied by creating various biopolymer hydrogel beads. Enzyme activity and encapsulation efficiency were notably enhanced by chitosan coating of alginate beads while leaching remained nearly unchanged. This was caused by the enzymatic reaction acidifying the matrix, which increased enzyme retention through enhanced electrostatic enzyme-alginate interaction but decreased activity through enzyme deactivation. A practical and ready-to-use method for visualising pH in beads during reaction by co-encapsulation of a conventional pH indicator was also found. Our method proves that pH control inside the beads can only be realised by buffering. The resulting beads provided a specific activity of 0.267 μmol ∙ min -1 ∙ mg -1 , effectiveness factor 0.88, encapsulation efficiency of 88%, 5% leaching and good recycling properties. This work will contribute towards better understanding and application of encapsulated hydrolases for enzymatic syntheses. Copyright © 2018 Elsevier B.V. All rights reserved.

Electrocatalysts having platium monolayers on palladium, palladium alloy, and gold alloy core-shell nanoparticles, and uses thereof

DOEpatents

Adzic, Radoslav; Mo, Yibo; Vukmirovic, Miomir; Zhang, Junliang

2010-12-21

The invention relates to platinum-coated particles useful as fuel cell electrocatalysts. The particles are composed of a noble metal or metal alloy core at least partially encapsulated by an atomically thin surface layer of platinum atoms. The invention particularly relates to such particles having a palladium, palladium alloy, gold alloy, or rhenium alloy core encapsulated by an atomic monolayer of platinum. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.

Probing insulin bioactivity in oral nanoparticles produced by ultrasonication-assisted emulsification/internal gelation

PubMed Central

Lopes, Marlene A; Abrahim-Vieira, Bárbara; Oliveira, Claudia; Fonte, Pedro; Souza, Alessandra M T; Lira, Tammy; Sequeira, Joana A D; Rodrigues, Carlos R; Cabral, Lúcio M; Sarmento, Bruno; Seiça, Raquel; Veiga, Francisco; Ribeiro, António J

2015-01-01

Alginate–dextran sulfate-based particles obtained by emulsification/internal gelation technology can be considered suitable carriers for oral insulin delivery. A rational study focused on the emulsification and particle recovery steps was developed in order to reduce particles to the nanosize range while keeping insulin bioactivity. There was a decrease in size when ultrasonication was used during emulsification, which was more pronounced when a cosurfactant was added. Ultrasonication add-on after particle recovery decreased aggregation and led to a narrower nanoscale particle-size distribution. Insulin encapsulation efficiency was 99.3%±0.5%, attributed to the strong pH-stabilizing electrostatic effect between insulin and nanoparticle matrix polymers. Interactions between these polymers and insulin were predicted using molecular modeling studies through quantum mechanics calculations that allowed for prediction of the interaction model. In vitro release studies indicated well-preserved integrity of nanoparticles in simulated gastric fluid. Circular dichroism spectroscopy proved conformational stability of insulin and Fourier transform infrared spectroscopy technique showed rearrangements of insulin structure during processing. Moreover, in vivo biological activity in diabetic rats revealed no statistical difference when compared to nonencapsulated insulin, demonstrating retention of insulin activity. Our results demonstrate that alginate–dextran sulfate-based nanoparticles efficiently stabilize the loaded protein structure, presenting good physical properties for oral delivery of insulin. PMID:26425087

Micro-Encapsulation of Probiotics

NASA Astrophysics Data System (ADS)

Meiners, Jean-Antoine

Micro-encapsulation is defined as the technology for packaging with the help of protective membranes particles of finely ground solids, droplets of liquids or gaseous materials in small capsules that release their contents at controlled rates over prolonged periods of time under the influences of specific conditions (Boh, 2007). The material encapsulating the core is referred to as coating or shell.

Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

NASA Astrophysics Data System (ADS)

Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki; Young Jeong, Hu; Galeano, Carolina; Schüth, Ferdi; Terasaki, Osamu

2014-11-01

Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Effects of melamine formaldehyde resin and CaCO3 diffuser-loaded encapsulation on correlated color temperature uniformity of phosphor-converted LEDs.

PubMed

Yang, Liang; Lv, Zhicheng; Jiaojiao, Yuan; Liu, Sheng

2013-08-01

Phosphor-free dispensing is the most widely used LED packaging method, but this method results in poor quality in angular CCT uniformity. This study proposes a diffuser-loaded encapsulation to solve the problem; the effects of melamine formaldehyde (MF) resin and CaCO3 loaded encapsulation on correlated color temperature (CCT) uniformity and luminous efficiency reduction of the phosphor-converted LEDs are investigated. Results reveal that MF resin loaded encapsulation has better light diffusion performance compared to MF resin loaded encapsulation at the same diffuser concentration, but CaCO3 loaded encapsulation has better luminous efficiency maintenance. The improvements in angular color uniformity for the LEDs emitting with MF resin and CaCO3 loaded encapsulation can be explained by the increase in photon scattering. The utility of this low cost and controllable mineral diffuser packaging method provides a practical approach for enhancing the angular color uniformity of LEDs. The diffuser mass ratio of 1% MF resin or 10% CaCO3 is the optimum condition to obtain low angular CCT variance and high luminous efficiency.

Polyamidoamine dendrimer conjugated chitosan nanoparticles for the delivery of methotrexate.

PubMed

Leng, Zhen-Hua; Zhuang, Qian-Fen; Li, Yan-Chao; He, Zeng; Chen, Zhao; Huang, Sai-Peng; Jia, Hong-Ying; Zhou, Jian-Wei; Liu, Yang; Du, Li-Bo

2013-10-15

Encapsulating anticancer drugs to synthetic polymer is a promising approach to improve the efficiency and reduce the side effects of anticancer drugs. In this study, novel chitosan derivatives with polyamidoamine moieties (CS-PAMAM) were synthesized and characterized by morphology, particle size, and zeta potential. Then the anticancer drug-methotrexate-encapsulated CS-PAMAM was prepared by hydrophobic-hydrophilic interactions. The drug release assay showed that the amount of the methotrexate release from CS-PAMAM was pH depended. Meanwhile, the cell viability assay illustrated that CS-PAMAM was suitable for the drug delivery because of its low cytotoxicity on cells. Moreover, our results showed that the CS-PAMAM could significantly improve the cytotoxicity of free methotrexate on A549 cells. These results demonstrate that CS-PAMAM may provide a suitable platform for the water-insoluble drug delivery. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chitosan/cashew gum nanogels for essential oil encapsulation.

PubMed

Abreu, Flávia O M S; Oliveira, Erick F; Paula, Haroldo C B; de Paula, Regina C M

2012-08-01

Nanogels based on chitosan and cashew gum were prepared and loaded with Lippia sidoides oil. Several parameters such as cashew gum concentration and relative oil content in the matrix had their influence on nanogel properties investigated. Nanogels were characterized regarding their morphologies, particle size distributions, zeta potential, Fourier transform infrared spectroscopy and essential oil contents. The release profile was investigated by UV/vis spectroscopy and its efficacy was determined through bioassays. Results showed that samples designed using relative ratios matrix:oil 10:2, gum:chitosan 1:1 and 5% gum concentration showed high loading (11.8%) and encapsulation efficiency (70%). Nanogels were found to exhibit average sizes in the range 335-558 nm. In vitro release profiles showed that nanoparticles presented slower and sustained release. Bioassays showed that larval mortality was related mainly to oil loading, with samples presenting more effective larvicide efficacies than the pure L. sidoides oil. Copyright © 2012 Elsevier Ltd. All rights reserved.

Drug loading and release on tumor cells using silk fibroin-albumin nanoparticles as carriers

NASA Astrophysics Data System (ADS)

Subia, B.; Kundu, S. C.

2013-01-01

Polymeric and biodegradable nanoparticles are frequently used in drug delivery systems. In this study silk fibroin-albumin blended nanoparticles were prepared using the desolvation method without any surfactant. These nanoparticles are easily internalized by the cells, reside within perinuclear spaces and act as carriers for delivery of the model drug methotrexate. Methotrexate loaded nanoparticles have better encapsulation efficiency, drug loading ability and less toxicity. The in vitro release behavior of methotrexate from the nanoparticles suggests that about 85% of the drug gets released after 12 days. The encapsulation and loading of a drug would depend on factors such as size, charge and hydrophobicity, which affect drug release. MTT assay and conjugation of particles with FITC demonstrate that the silk fibroin-albumin nanoparticles do not affect the viability and biocompatibility of cells. This blended nanoparticle, therefore, could be a promising nanocarrier for the delivery of drugs and other bioactive molecules.

Oil-in-water emulsions for encapsulated delivery of reactive iron particles.

PubMed

Berge, Nicole D; Ramsburg, C Andrew

2009-07-01

Treatment of dense nonaqueous phase liquid (DNAPL) source zones using suspensions of reactive iron particles relies upon effective transport of the nano- to submicrometer scale iron particles within the subsurface. Recognition that poor subsurface transport of iron particles results from particle-particle and particle-soil interactions permits development of strategies which increase transport. In this work, experiments were conducted to assess a novel approach for encapsulated delivery of iron particles within porous media using oil-in-water emulsions. Objectives of this study included feasibility demonstration of producing kinetically stable, iron-containing, oil-in-water emulsions and evaluating the transport of these iron-containing, oil-in-water emulsions within water-saturated porous media. Emulsions developed in this study have mean droplet diameters between 1 and 2 microm, remain kinetically stable for > 1.5 h, and possess densities (0.996-1.00 g/mL at 22 degrees C) and dynamic viscosities (2.4-9.3 mPa x s at 22 degrees C and 20 s(-1)) that are favorable to transport within DNAPL source zones. Breakthrough curves and post-experiment extractions from column experiments conducted with medium and fine sands suggest little emulsion retention (< 0.20% wt) at a Darcy velocity of 0.4 m/day. These findings demonstrate that emulsion encapsulation is a promising method for delivery of iron particles and warrants further investigation.

Encapsulation of Naproxen in Lipid-Based Matrix Microspheres: Characterization and Release Kinetics

PubMed Central

Bhoyar, PK; Morani, DO; Biyani, DM; Umekar, MJ; Mahure, JG; Amgaonkar, YM

2011-01-01

The objective of this study was to microencapsulate the anti-inflammatory drug (naproxen) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. Naproxen was microencapsulated with lipid-like carnauba wax, hydrogenated castor oil using modified melt dispersion (modified congealable disperse phase encapsulation) technique. Effect of various formulation and process variables such as drug-lipid ratio, concentration of modifier, concentration of dispersant, stirring speed, stirring time, temperature of external phase, on evaluatory parameters such as size, entrapment efficiency, and in vitro release of naproxen were studied. The microspheres were characterized for particle size, scanning electron microscopy (SEM), FT-IR spectroscopy, drug entrapment efficiency, in vitro release studies, for in vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of various batches of microspheres was found to be ranging from 60 to 90 %w/w. In vitro drug release studies were carried out up to 24 h in pH 7.4 phosphate buffer showing 50-65% drug release. In vitro drug release from all the batches showed better fitting with the Korsmeyer-Peppas model, indicating the possible mechanism of drug release to be by diffusion and erosion of the lipid matrix. PMID:21731354

Encapsulation of naproxen in lipid-based matrix microspheres: characterization and release kinetics.

PubMed

Bhoyar, P K; Morani, D O; Biyani, D M; Umekar, M J; Mahure, J G; Amgaonkar, Y M

2011-04-01

The objective of this study was to microencapsulate the anti-inflammatory drug (naproxen) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. Naproxen was microencapsulated with lipid-like carnauba wax, hydrogenated castor oil using modified melt dispersion (modified congealable disperse phase encapsulation) technique. Effect of various formulation and process variables such as drug-lipid ratio, concentration of modifier, concentration of dispersant, stirring speed, stirring time, temperature of external phase, on evaluatory parameters such as size, entrapment efficiency, and in vitro release of naproxen were studied. The microspheres were characterized for particle size, scanning electron microscopy (SEM), FT-IR spectroscopy, drug entrapment efficiency, in vitro release studies, for in vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of various batches of microspheres was found to be ranging from 60 to 90 %w/w. In vitro drug release studies were carried out up to 24 h in pH 7.4 phosphate buffer showing 50-65% drug release. In vitro drug release from all the batches showed better fitting with the Korsmeyer-Peppas model, indicating the possible mechanism of drug release to be by diffusion and erosion of the lipid matrix.

Development and in vivo evaluation of self-microemulsion as delivery system for α-mangostin.

PubMed

Xu, Wen-Ke; Jiang, Hui; Yang, Kui; Wang, Ya-Qin; Zhang, Qian; Zuo, Jian

2017-03-01

α-Mangostin (MG) is a versatile bioactive compound isolated from mangosteen and possesses significant pharmacokinetic shortages. To augment the potential clinical efficacy, MG-loaded self-microemulsion (MG-SME) was designed and prepared in this study, and its potential as a drug loading system was evaluated based on the pharmacokinetic performance and tissue distribution feature. The formula of MG-SME was optimized by an orthogonal test under the guidance of ternary phase diagram, and the prepared MG-SME was characterized by encapsulation efficiency, size distribution, and morphology. Optimized high performance liquid chromatography method was employed to determine concentrations of MG and characterize the pharmacokinetic and tissue distribution features of MG in rodents. It was found that diluted MG-SME was characterized as spherical particles with a mean diameter of 24.6 nm and an encapsulation efficiency of 87.26%. The delivery system enhanced the area under the curve of MG by 4.75 times and increased the distribution in lymphatic organs. These findings suggested that SME as a nano-sized delivery system efficiently promoted the digestive tract absorption of MG and modified its distribution in tissues. The targeting feature and high oral bioavailability of MG-SME promised a good clinical efficacy, especially for immune diseases. Copyright © 2017. Published by Elsevier Taiwan.

Microfabrication of curcumin-loaded microparticles using coaxial electrohydrodynamic atomization

NASA Astrophysics Data System (ADS)

Yuan, Shuai; Si, Ting; Liu, Zhongfa; Xu, Ronald X.

2014-03-01

Encapsulation of curcumin in PLGA microparticles is performed by a coaxial electrohydrodynamic atomization device. To optimize the process, the effects of different control parameters on morphology and size distribution of resultant microparticles are studied systemically. Four main flow modes are identified as the applied electric field intensity increases. The stable cone-jet configuration is found to be available for fabricating monodisperse microparticles with core-shell structures. The results are compared with those observed in traditional emulsion. The drug-loading efficiency is also checked. The present system is advantageous for the enhancement of particle size distribution and drug-loading efficiency in various applications such as drug delivery, biomedicine and image-guided therapy.

PEGylated lipid nanocapsules with improved drug encapsulation and controlled release properties.

PubMed

Hervella, Pablo; Alonso-Sande, Maria; Ledo, Francisco; Lucero, Maria L; Alonso, Maria J; Garcia-Fuentes, Marcos

2014-01-01

Drugs with poor lipid and water solubility are some of the most challenging to formulate in nanocarriers, typically resulting in low encapsulation efficiencies and uncontrolled release profiles. PEGylated nanocapsules (PEG-NC) are known for their amenability to diverse modifications that allow the formation of domains with different physicochemical properties, an interesting feature to address a drug encapsulation problem. We explored this problem by encapsulating in PEG-NC the promising anticancer drug candidate F10320GD1, used herein as a model for compounds with such characteristics. The nanocarriers were prepared from Miglyol(®), lecithin and PEG-sterate through a solvent displacement technique. The resulting system was a homogeneous suspension of particles with size around 200 nm. F10320GD1 encapsulation was found to be very poor (<15%) if PEG-NC were prepared using water as continuous phase; but we were able to improve this value to 85% by fixing the pH of the continuous phase to 9. Interestingly, this modification also improved the controlled release properties and the chemical stability of the formulation during storage. These differences in pharmaceutical properties together with physicochemical data suggest that the pH of the continuous phase used for PEG-NC preparation can modify drug allocation, from the external shell towards the inner lipid core of the nanocapsules. Finally, we tested the bioactivity of the drug-loaded PEG-NC in several tumor cell lines, and also in endothelial cells. The results indicated that drug encapsulation led to an improvement on drug cytotoxicity in tumor cells, but not in non-tumor endothelial cells. Altogether, the data confirms that PEG-NC show adequate delivery properties for F10320GD1, and underlines its possible utility as an anticancer therapy.

Dual-modality, fluorescent, PLGA encapsulated bismuth nanoparticles for molecular and cellular fluorescence imaging and computed tomography.

PubMed

Swy, Eric R; Schwartz-Duval, Aaron S; Shuboni, Dorela D; Latourette, Matthew T; Mallet, Christiane L; Parys, Maciej; Cormode, David P; Shapiro, Erik M

2014-11-07

Reports of molecular and cellular imaging using computed tomography (CT) are rapidly increasing. Many of these reports use gold nanoparticles. Bismuth has similar CT contrast properties to gold while being approximately 1000-fold less expensive. Herein we report the design, fabrication, characterization, and CT and fluorescence imaging properties of a novel, dual modality, fluorescent, polymer encapsulated bismuth nanoparticle construct for computed tomography and fluorescence imaging. We also report on cellular internalization and preliminary in vitro and in vivo toxicity effects of these constructs. 40 nm bismuth(0) nanocrystals were synthesized and encapsulated within 120 nm Poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles by oil-in-water emulsion methodologies. Coumarin-6 was co-encapsulated to impart fluorescence. High encapsulation efficiency was achieved ∼70% bismuth w/w. Particles were shown to internalize within cells following incubation in culture. Bismuth nanocrystals and PLGA encapsulated bismuth nanoparticles exhibited >90% and >70% degradation, respectively, within 24 hours in acidic, lysosomal environment mimicking media and both remained nearly 100% stable in cytosolic/extracellular fluid mimicking media. μCT and clinical CT imaging was performed at multiple X-ray tube voltages to measure concentration dependent attenuation rates as well as to establish the ability to detect the nanoparticles in an ex vivo biological sample. Dual fluorescence and CT imaging is demonstrated as well. In vivo toxicity studies in rats revealed neither clinically apparent side effects nor major alterations in serum chemistry and hematology parameters. Calculations on minimal detection requirements for in vivo targeted imaging using these nanoparticles are presented. Indeed, our results indicate that these nanoparticles may serve as a platform for sensitive and specific targeted molecular CT and fluorescence imaging.

The effect of colloidal silica nanoparticles encapsulated fluorescein dye using micelle entrapment method

NASA Astrophysics Data System (ADS)

Ahmad, Atiqah; Zakaria, Nor Dyana; Lockman, Zainovia; Razak, Khairunisak Abdul

2018-05-01

The advancement of nanoparticle-based approaches such as quantum dots (QDs), metallic (Au and Ag) NPs, silica NPs and other types of nanomaterial have led to a large variety of biomolecular imaging and labelling reagents with controlled size and shaped to overcome the limitation of conventional organic dye. In this study, the yellowish green color of fluorescein dye was encapsulated into colloidal silica nanoparticles by using micelle entrapment approach. Two different size of silica nanoparticles encapsulated fluorescein dye (27.7 ± 5.6 and 46.73 ± 4.3 nm) with spherical and monodispered of nanoparticles were synthesised by varying the volume of co-solvent during the synthesis process. The particles size, particles morphology, absorption spectrum and the photostability of fluorescein dye was measured by using dynamic light scaterring (DLS), Transmission Electron Microscope (TEM) and UV-Vis spectrometer. Furthermore, the effect of photostability of of silica nanoparticles encapsulated fluorescein dye was measured under radiation of 200 W of Halogen lamp for 60 minutes. The silica nanoparticles encapsulated fluorescein dye was more stable compared to bare fluorescein dye after the exposure. In conclusion, the photostability of silica nanoparticles encapsulated fluorescein dye was improved compared to bare fluorescein dye, thus silica nanoparticles encapsulation successfully provides protection from the photobleaching and photodegradation of fluorescein dye.

Adjuvant-carrying synthetic vaccine particles augment the immune response to encapsulated antigen and exhibit strong local immune activation without inducing systemic cytokine release

PubMed Central

Ilyinskii, Petr O.; Roy, Christopher J.; O’Neil, Conlin P.; Browning, Erica A.; Pittet, Lynnelle A.; Altreuter, David H.; Alexis, Frank; Tonti, Elena; Shi, Jinjun; Basto, Pamela A.; Iannacone, Matteo; Radovic-Moreno, Aleksandar F.; Langer, Robert S.; Farokhzad, Omid C.; von Andrian, Ulrich H.; Johnston, Lloyd P.M.; Kishimoto, Takashi Kei

2014-01-01

Augmentation of immunogenicity can be achieved by particulate delivery of an antigen and by its co-administration with an adjuvant. However, many adjuvants initiate strong systemic inflammatory reactions in vivo, leading to potential adverse events and safety concerns. We have developed a synthetic vaccine particle (SVP) technology that enables co-encapsulation of antigen with potent adjuvants. We demonstrate that co-delivery of an antigen with a TLR7/8 or TLR9 agonist in synthetic polymer nanoparticles results in a strong augmentation of humoral and cellular immune responses with minimal systemic production of inflammatory cytokines. In contrast, antigen encapsulated into nanoparticles and admixed with free TLR7/8 agonist leads to lower immunogenicity and rapid induction of high levels of inflammatory cytokines in the serum (e.g., TNF-α and IL-6 levels are 50- to 200-fold higher upon injection of free resiquimod (R848) than of nanoparticle-encapsulated R848). Conversely, local immune stimulation as evidenced by cellular infiltration of draining lymph nodes and by intranodal cytokine production was more pronounced and persisted longer when SVP-encapsulated TLR agonists were used. The strong local immune activation achieved using a modular self-assembling nanoparticle platform markedly enhanced immunogenicity and was equally effective whether antigen and adjuvant were co-encapsulated in a single nanoparticle formulation or co-delivered in two separate nanoparticles. Moreover, particle encapsulation enabled the utilization of CpG oligonucleotides with the natural phosphodiester backbone, which are otherwise rapidly hydrolyzed by nucleases in vivo. The use of SVP may enable clinical use of potent TLR agonists as vaccine adjuvants for indications where cellular immunity or robust humoral responses are required. PMID:24593999

ENGINEERING BULLETIN: SOLIDIFICATION/STABILIZATION OF ORGANICS AND INORGANICS

EPA Science Inventory

Solidification refers to techniques that encapsulate hazardous waste into a solid material of high structural integrity. Encapsulation involves either fine waste particles (microencapsulation) or a large block or container of wastes (macroencapsulation). Stabilization refe...

Encapsulation of NF-κ B Decoy Oligonucleotides within Echogenic Liposomes and Ultrasound-Triggered Release

PubMed Central

Buchanan, Kyle D.; Huang, Shao-Ling; Kim, Hyunggun; McPherson, David D.; MacDonald, Robert C.

2011-01-01

Echogenic liposomes (ELIP) have additional promise, beyond diagnostic agents, as vehicles for delivering oligonucleotides (ODN), especially if the release of the agent can be triggered and its uptake can be enhanced by ultrasound application at a specific site. The purpose of this study was to co-encapsulate air and NF-κB decoy ODN within ELIP allowing ultrasound to release encapsulated ODN from ELIP, and to accurately quantify release of encapsulated ODN from ELIP upon ultrasound application. FITC-labeled sense ODN (2 mM) was incorporated within ELIP using freeze/thaw method. Encapsulation efficiency of FITC-ODN was spectrofluorometrically analyzed by quenching fluorescence of unencapsulated FITC-ODN using a complementary strand tagged with Iowa Black FQ-ODN. Quenching of FITC-ODN (0.05 μM) with Iowa Black FQ-ODN (0.1 μM) was found to be efficient (92.4 ± 0.2 %), allowing accurate determination of encapsulated ODN. Encapsulation efficiency of ODN was 14.2 ± 2.5 % in DPPC/DOPC/DPPG/CH liposomes and 29.6 ± 1.5 % in DPPC/DOPE/DPPG/CH liposomes. Application of ultrasound (1 MHz continuous wave, 0.26 MPa peak-to-peak pressure amplitude, 60 seconds.) to the latter formulation triggered 41.6 ± 4.3 % release of ODN from ODN-containing ELIP. We have thus demonstrated that ODN can be encapsulated into ELIP and released efficiently upon ultrasound application. These findings suggest potential applications for gene therapy in atherosclerosis treatment. PMID:19804805

Curcumin drug delivery by vanillin-chitosan coated with calcium ferrite hybrid nanoparticles as carrier.

PubMed

Kamaraj, Sriram; Palanisamy, Uma Maheswari; Kadhar Mohamed, Meera Sheriffa Begum; Gangasalam, Arthanareeswaran; Maria, Gover Antoniraj; Kandasamy, Ruckmani

2018-04-30

The aim of the present investigation is the development, optimization and characterization of curcumin-loaded hybrid nanoparticles of vanillin-chitosan coated with super paramagnetic calcium ferrite. The functionally modified vanillin-chitosan was prepared by the Schiff base reaction to enhance the hydrophobic drug encapsulation efficiency. Calcium ferrite (CFNP) nano particles were added to the vanillin modified chitosan to improve the biocompatibility. The vanillin-chitosan-CFNP, hybrid nanoparticle carrier was obtained by ionic gelation method. Characterizations of the hybrid materials were performed by XRD, FTIR, 1 H NMR, TGA, AFM and SEM techniques to ensure the modifications on the chitosan material. Taguchi method was applied to optimize the drug (curcumin) encapsulation efficiency by varying the drug to chitosan-vanillin, CFNP to chitosan-vanillin and TPP (sodium tripolyphospate) to chitosan-vanillin ratios. The maximum encapsulation efficiency was obtained as 98.3% under the conditions of 0.1, 0.75 and 1.0 for the drug to chitosan-vanillin, CFNP to chitosan-vanillin and TPP to chitosan-vanillin ratios, respectively. The curcumin release was performed at various pH, initial drug loading concentrations and magnetic fields. The drug release mechanism was predicted by fitting the experimental kinetic data with various drug release models. The drug release profiles showed the best fit with Higuchi model under the most of conditions. The drug release mechanism followed both non-Fickian diffusion and case II transport mechanism for chitosan, however the non-Fickian diffusion mechanism was followed for the vanillin modified chitosan. The biocompatibility of the hybrid material was tested using L929 fibroblast cells. The cytotoxicity test was performed against MCF-7 breast cancer cell line to check the anticancer property of the hybrid nano carrier with the curcumin drug. Copyright © 2018 Elsevier B.V. All rights reserved.

Self-Assembled Lipid Nanoparticles for Oral Delivery of Heparin-Coated Iron Oxide Nanoparticles for Theranostic Purposes.

PubMed

Truzzi, Eleonora; Bongio, Chiara; Sacchetti, Francesca; Maretti, Eleonora; Montanari, Monica; Iannuccelli, Valentina; Vismara, Elena; Leo, Eliana

2017-06-09

Recently, solid lipid nanoparticles (SLNs) have attracted increasing attention owing to their potential as an oral delivery system, promoting intestinal absorption in the lymphatic circulation which plays a role in disseminating metastatic cancer cells and infectious agents throughout the body. SLN features can be exploited for the oral delivery of theranostics. Therefore, the aim of this work was to design and characterise self-assembled lipid nanoparticles (SALNs) to encapsulate and stabilise iron oxide nanoparticles non-covalently coated with heparin (Fe@hepa) as a model of a theranostic tool. SALNs were characterised for physico-chemical properties (particle size, surface charge, encapsulation efficiency, in vitro stability, and heparin leakage), as well as in vitro cytotoxicity by methyl thiazole tetrazolium (MTT) assay and cell internalisation in CaCo-2, a cell line model used as an indirect indication of intestinal lymphatic absorption. SALNs of about 180 nm, which are stable in suspension and have a high encapsulation efficiency (>90%) were obtained. SALNs were able to stabilise the heparin coating of Fe@hepa, which are typically unstable in physiological environments. Moreover, SALNs-Fe@hepa showed no cytotoxicity, although their ability to be internalised into CaCo-2 cells was highlighted by confocal microscopy analysis. Therefore, the results indicated that SALNs can be considered as a promising tool to orally deliver theranostic Fe@hepa into the lymphatic circulation, although further in vivo studies are needed to comprehend further potential applications.

Dorzolamide-loaded PLGA/vitamin E TPGS nanoparticles for glaucoma therapy: Pharmacoscintigraphy study and evaluation of extended ocular hypotensive effect in rabbits.

PubMed

Warsi, Musarrat H; Anwar, Mohammed; Garg, Vaidehi; Jain, Gaurav K; Talegaonkar, Sushama; Ahmad, Farhan J; Khar, Roop K

2014-10-01

Poor drug penetration and rapid clearance after topical instillation of a drug formulation into the eyes are the major causes for the lower ocular bioavailability from conventional eye drops. Along with this, poor encapsulation efficiency of hydrophilic drug in polymeric nanoparticles remains a major formulation challenge. Taking this perspective into consideration, dorzolamide (DZ)-loaded PLGA nanoparticles were developed employing two different emulsifiers (PVA and vitamin E TPGS) and the effects of various formulation and process variables on particle size and encapsulation efficiency were assessed. Nanoparticles emulsified with vitamin E TPGS (DZ-T-NPs) were found to possess enhanced drug encapsulation (59.8±6.1%) as compared to those developed with PVA as emulsifier (DZ-P-NPs). Transcorneal permeation study revealed a significant enhancement in permeation (1.8-2.5 fold) as compared to solution. In addition, ex vivo biodistribution study showed a higher concentration of drug in the aqueous humour (1.5-2.3 fold). Histological and IR-camera studies proved the non-irritant potential of the formulations. Pharmacoscintigraphic studies revealed the reduced corneal clearance, as well as naso-lachrymal drainage in comparison to drug solution. Furthermore, efficacy study revealed that DZ-P-NPs and DZ-T-NPs significantly reduced the intraocular pressure by 22.81% and 29.12%, respectively, after a single topical instillation into the eye. Copyright © 2014 Elsevier B.V. All rights reserved.

Fluorescence imaging of antibiotic clofazimine encapsulated within mesoporous silica particle carriers: relevance to drug delivery and the effect on its release kinetics.

PubMed

Angiolini, Lorenzo; Valetti, Sabrina; Cohen, Boiko; Feiler, Adam; Douhal, Abderrazzak

2018-05-03

We report on the encapsulation of the antibiotic clofazimine (CLZ) within the pores of mesoporous silica particles having hydrophilic (CBET value of 137) and more hydrophobic (CBET value of 94 after calcination at 600 °C) surfaces. We studied the effect of pH on the released amount of CLZ in aqueous solutions and observed a maximum at pH 4.1 in correlation with the solubility of the drug. Less release of the drug was observed from the more hydrophobic particles which was attributed to a difference in the affinity of the drug to the carrier particles. Fluorescence lifetime imaging microscopy, emission spectra, and fluorescence lifetimes of single drug loaded particles provided detailed understanding and new knowledge of the physical form of the encapsulated drug and the distribution within the particles. The distribution of CLZ within the particles was independent of the surface chemistry of the particles. The confirmation of CLZ molecules as monomers or aggregates was revealed by controlled removal of the drug with solvent. Additionally, the observed optical "halo effect" in the fluorescent images was interpreted in terms of specific quenching of high concentration of molecules. The emission lifetime experiments suggest stronger interaction of CLZ with the more hydrophobic particles, which is relevant to its release. The results reported in this work demonstrate that tuning the hydrophilicity/hydrophobicity of mesoporous silica particles can be used as a tool to control the release without impacting their loading ability.

Fabrication of uniform multi-compartment particles using microfludic electrospray technology for cell co-culture studies.

PubMed

Liu, Zhou; Shum, Ho Cheung

2013-01-01

In this work, we demonstrate a robust and reliable approach to fabricate multi-compartment particles for cell co-culture studies. By taking advantage of the laminar flow within our microfluidic nozzle, multiple parallel streams of liquids flow towards the nozzle without significant mixing. Afterwards, the multiple parallel streams merge into a single stream, which is sprayed into air, forming monodisperse droplets under an electric field with a high field strength. The resultant multi-compartment droplets are subsequently cross-linked in a calcium chloride solution to form calcium alginate micro-particles with multiple compartments. Each compartment of the particles can be used for encapsulating different types of cells or biological cell factors. These hydrogel particles with cross-linked alginate chains show similarity in the physical and mechanical environment as the extracellular matrix of biological cells. Thus, the multi-compartment particles provide a promising platform for cell studies and co-culture of different cells. In our study, cells are encapsulated in the multi-compartment particles and the viability of cells is quantified using a fluorescence microscope after the cells are stained for a live/dead assay. The high cell viability after encapsulation indicates the cytocompatibility and feasibility of our technique. Our multi-compartment particles have great potential as a platform for studying cell-cell interactions as well as interactions of cells with extracellular factors.

Fabrication of uniform multi-compartment particles using microfludic electrospray technology for cell co-culture studies

PubMed Central

Liu, Zhou; Shum, Ho Cheung

2013-01-01

In this work, we demonstrate a robust and reliable approach to fabricate multi-compartment particles for cell co-culture studies. By taking advantage of the laminar flow within our microfluidic nozzle, multiple parallel streams of liquids flow towards the nozzle without significant mixing. Afterwards, the multiple parallel streams merge into a single stream, which is sprayed into air, forming monodisperse droplets under an electric field with a high field strength. The resultant multi-compartment droplets are subsequently cross-linked in a calcium chloride solution to form calcium alginate micro-particles with multiple compartments. Each compartment of the particles can be used for encapsulating different types of cells or biological cell factors. These hydrogel particles with cross-linked alginate chains show similarity in the physical and mechanical environment as the extracellular matrix of biological cells. Thus, the multi-compartment particles provide a promising platform for cell studies and co-culture of different cells. In our study, cells are encapsulated in the multi-compartment particles and the viability of cells is quantified using a fluorescence microscope after the cells are stained for a live/dead assay. The high cell viability after encapsulation indicates the cytocompatibility and feasibility of our technique. Our multi-compartment particles have great potential as a platform for studying cell-cell interactions as well as interactions of cells with extracellular factors. PMID:24404050

Syntheses and self-assembly of novel asparagine-derived amphiphiles: Applications in the encapsulation of proteins, hydrophobic, and hydrophilic drug models

NASA Astrophysics Data System (ADS)

Mfuh, Adelphe Mbufung

This thesis focuses mainly on the synthesis, characterization, and self-assembly of a novel series of asparagine-derived amphiphiles and their use in the preparation and stabilization of nano and microcapsules for the encapsulation of proteins, and hydrophilic and hydrophobic drug models. Chapter 1 gives a brief literature overview of lipid molecular assembly, which covers some aspects of morphological analyses, encapsulation of chemical entity and some reported characterization techniques of supramolecular assemblies. It introduces the scope of this dissertation and contains some information on stimulus responsive liposomal systems for controlled release of drug models. Chapter 2 introduces a novel asparagine-derived lipid bearing two fatty chains (C11 and C17) and a tetrahydropyrimidinone head group. It presents information on the synthesis and characterization of this lipid and describes the self-assembly and effects of this lipid in distearoyl phosphatidyl choline bilayer. Chapter 3 presents the synthesis and characterization of a series of ALAn,m (where n and m represent the length of the hydrocarbon chains on the asparagine-derived, heterocyclic head group). It contains data on the effect of chain length, solvent media and head group ionization on the conformational equilibrium about a tertiary amide bond in ALAn,m. The chapter also examines the influence of chain length on ALAn,m on the colloidal stability of DSPC liposomes. Chapter 4 presents the first example of an N,N-acetal linkage in a novel pH responsive nanocarrier system obtained from the cyclocondensation of dodecanal with sodium asparaginate. Data is presented on the spontaneous self-assembly, encapsulation studies and morphological characterization of the nano-systems with the inclusion of cholesterol as additive. Chapter 5 presents the development of a photoresponsive nanocarrier via the self- assembly of an asparagine-derived lipid containing a coumarin unit in the hydrophobic domain. The supramolecular assemblies of this lipid were examined for the ability to encapsulate and release chemical entity in response to UV-assisted [2+2]-photodimerization. Chapter 6 presents the fabrication of an organic core/inorganic shell microcapsules from the catanionic self-assemblies of a series of symmetrical asparagine-derived bolaamphiphiles and polyallyl amine, followed by surfacing coating with silica nanoparticles. Unlike layer-by-layer or polymer salt aggregates (PSA) capsules reported in the chemical literature, these particles show encapsulation for wider range of chemical entities with different solubility properties. Studies suggest that these particles efficiently encapsulated protoporphyrin IX. dimethylester, doxorubicin and a fluorescently labeled bovine serum albumin (FITC-BSA).

Application of supercritical antisolvent method in drug encapsulation: a review

PubMed Central

Kalani, Mahshid; Yunus, Robiah

2011-01-01

The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution. PMID:21796245

Technological process for cell disruption, extraction and encapsulation of astaxanthin from Haematococcus pluvialis.

PubMed

Machado, Francisco R S; Trevisol, Thalles C; Boschetto, Daiane L; Burkert, Janaína F M; Ferreira, Sandra R S; Oliveira, J Vladimir; Burkert, Carlos André V

2016-01-20

In this work, the effectiveness of different enzymatic techniques for cell wall disruption of Haematococcus pluvialis for the extraction of carotenoids and subsequent encapsulation of extracts in the co-polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) using the Solution Enhanced Dispersion by Supercritical fluids (SEDS) technique was investigated. Glucanex(®) performed best compared with Lyticase(®) and Driselase(®). The conditions for enzymatic lysis using this enzyme preparation were established as a pH of 4.5, a temperature of 55 °C, an initial activity of β-1,3-glucanase of 0.6 U mL(-1) and a reaction time of 30 min. Enzymatic lysis assisted by ultrasound without biomass freezing was shown to be a promising and simple one-step technique for cell wall disruption, reaching 83.90% extractability. In the co-precipitation experiments, the highest encapsulation efficiency (51.21%) was obtained when using a higher biomass to dichloromethane ratio (10 mg mL(-1)) at the carotenoid extraction step and a lower pressure of precipitation (80 bar). In these conditions, spherical particles in the micrometer range (0.228 μm) were obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

Atorvastatin calcium encapsulated eudragit nanoparticles with enhanced oral bioavailability, safety and efficacy profile.

PubMed

Kumar, Nagendra; Chaurasia, Sundeep; Patel, Ravi R; Khan, Gayasuddin; Kumar, Vikas; Mishra, Brahmeshwar

2017-03-01

Atorvastatin calcium (ATR), a second generation statin drug, was encapsulated in eudragit RSPO-based polymeric nanoparticles. The effect of independent variables (polymer content, stabilizer concentration, volume of chloroform and homogenization speed) on response variables (mean diameter particle size and entrapment efficiency) were investigated by employing central composite experimental design. All the independent variables were found to be significant for determining the response variables. Solid-state characterization study indicated the absence of physicochemical interaction between drug and polymer in formulation. Morphological study exhibited homogenous spherical shape of formulated nanoparticles. In vitro release study in phosphate buffer (pH 7.4) demonstrated sustained release profile over 24 h. Pharmacokinetic study in Charles Foster rats showed significant enhancement in oral bioavailability as compared to pure drug suspension. Efficacy study (lipid profile and blood glucose level) significantly justified the effectiveness of formulation having 50% less dose of ATR as compared to pure drug suspension. The effectiveness of formulation was further justified with an improved plasma safety profile of treated rats. Hence, ATR encapsulated eudragit RSPO nanoparticles can serve as potential drug delivery approach to enhance drug bioavailability, efficacy and safety profiles to alter existing marketed drug products.

Hepatitis Virus Capsid Polymorphs Respond Differently to Changes in Encapsulated Cargo Size

PubMed Central

He, Li; Porterfield, J. Zachary; van der Schoot, Paul; Zlotnick, Adam; Dragnea, Bogdan

2017-01-01

A templated assembly approach for Hepatitis B virus-like particles was employed to determine how the T = 3 and T = 4 polymorphs of the Hepatitis B virus (HBV) icosahedral cores respond to a systematic, gradual change in the encapsulated cargo size. It was found that assembly into complete virus-like particles occurs cooperatively around a variety of core diameters, albeit the degree of cooperativity varies. Among these virus-like particles, it was found that those of an outer diameter similar to T = 4 are able to accommodate the widest range of cargo sizes. PMID:24010404

Comparison of anti-EGFR-Fab’ conjugated immunoliposomes modified with two different conjugation linkers for siRNa delivery in SMMC-7721 cells

PubMed Central

Deng, Li; Zhang, Yingying; Ma, Lulu; Jing, Xiaolong; Ke, Xingfa; Lian, Jianhao; Zhao, Qiang; Yan, Bo; Zhang, Jinfeng; Yao, Jianzhong; Chen, Jianming

2013-01-01

Background Targeted liposome-polycation-DNA complex (LPD), mainly conjugated with antibodies using functionalized PEG derivatives, is an effective nanovector for systemic delivery of small interference RNA (siRNA). However, there are few studies reporting the effect of different conjugation linkers on LPD for gene silencing. To clarify the influence of antibody conjugation linkers on LPD, we prepared two different immunoliposomes to deliver siRNA in which DSPE-PEG-COOH and DSPE-PEG-MAL, the commonly used PEG derivative linkers, were used to conjugate anti-EGFR Fab’ with the liposome. Methods First, 600 μg of anti-EGFR Fab’ was conjugated with 28.35 μL of a micelle solution containing DSPE-PEG-MAL or DSPE-PEG-COOH, and then post inserted into the prepared LPD. Various liposome parameters, including particle size, zeta potential, stability, and encapsulation efficiency were evaluated, and the targeting ability and gene silencing activity of TLPD-FPC (DSPE-PEG-COOH conjugated with Fab’) was compared with that of TLPD-FPM (DSPE-PEG-MAL conjugated with Fab’) in SMMC-7721 hepatocellular carcinoma cells. Results There was no significant difference in particle size between the two TLPDs, but the zeta potential was significantly different. Further, although there was no significant difference in siRNA encapsulation efficiency, cell viability, or serum stability between TLPD-FPM and TLPD-FPC, cellular uptake of TLPD-FPM was significantly greater than that of TLPD-FPC in EGFR-overexpressing SMMC-7721 cells. The luciferase gene silencing efficiency of TLPD-FPM was approximately three-fold high than that of TLPD-FPC. Conclusion Different conjugation linkers whereby antibodies are conjugated with LPD can affect the physicochemical properties of LPD and antibody conjugation efficiency, thus directly affecting the gene silencing effect of TLPD. Immunoliposomes prepared by DSPE-PEG-MAL conjugation with anti-EGFR Fab’ are more effective than TLPD containing DSPE-PEG-COOH in targeting hepatocellular carcinoma cells for siRNA delivery. PMID:24023515

Evaluating Trichloroethylene Degradation Using Differing Nano- and Micro-Scale Iron Particles

NASA Technical Reports Server (NTRS)

Berger, Cristina M.; Geiger, Cherie L.; Clausen, Christian A.; Billow, Alexa M.; Quinn, Jacqueline W.; Brooks, Kathleen B.

2006-01-01

Trichioroethylene, or TCE, is a central nervous system depressant and possible carcinogen, as well as a persistent groundwater pollutant. TCE exists in the aquifer either as free product in the form of a dense non-aqueous phase liquid (DNAPL) or as a dissolved-phase constituent. It is only slightly soluble in water, so dissolution of the contaminant is a long-term process and in-situ remediation is difficult. To remedy this, NASA and the University of Central Florida developed Emulsified Zero-Valent Iron, or EZVI. The emulsion droplet contains ZVI particles and water encapsulated by an oil/surfactant membrane, and effectively penetrates to degrade DNAPL-phase TCE. To maximize the efficiency of this process, several commercially available ZVIs of radically different particle sizes and morphologies both in emulsion and as neat (unemulsified) metal were evaluated for relative effectiveness at TCE degradation.

T1-Weighted MR imaging of liver tumor by gadolinium-encapsulated glycol chitosan nanoparticles without non-specific toxicity in normal tissues

NASA Astrophysics Data System (ADS)

Na, Jin Hee; Lee, Sangmin; Koo, Heebeom; Han, Hyounkoo; Lee, Kyung Eun; Han, Seung Jin; Choi, Seung Hong; Kim, Hyuncheol; Lee, Seulki; Kwon, Ick Chan; Choi, Kuiwon; Kim, Kwangmeyung

2016-05-01

Herein, we have synthesized Gd(iii)-encapsulated glycol chitosan nanoparticles (Gd(iii)-CNPs) for tumor-targeted T1-weighted magnetic resonance (MR) imaging. The T1 contrast agent, Gd(iii), was successfully encapsulated into 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-modified CNPs to form stable Gd(iii)-encapsulated CNPs (Gd(iii)-CNPs) with an average particle size of approximately 280 nm. The stable nanoparticle structure of Gd(iii)-CNPs is beneficial for liver tumor accumulation by the enhanced permeation and retention (EPR) effect. Moreover, the amine groups on the surface of Gd(iii)-CNPs could be protonated and could induce fast cellular uptake at acidic pH in tumor tissue. To assay the tumor-targeting ability of Cy5.5-labeled Gd(iii)-CNPs, near-infrared fluorescence (NIRF) imaging and MR imaging were used in a liver tumor model as well as a subcutaneous tumor model. Cy5.5-labeled Gd(iii)-CNPs generated highly intense fluorescence and T1 MR signals in tumor tissues after intravenous injection, while DOTAREM®, the commercialized control MR contrast agent, showed very low tumor-targeting efficiency on MR images. Furthermore, damaged tissues were found in the livers and kidneys of mice injected with DOTAREM®, but there were no obvious adverse effects with Gd(iii)-CNPs. Taken together, these results demonstrate the superiority of Gd(iii)-CNPs as a tumor-targeting T1 MR agent.Herein, we have synthesized Gd(iii)-encapsulated glycol chitosan nanoparticles (Gd(iii)-CNPs) for tumor-targeted T1-weighted magnetic resonance (MR) imaging. The T1 contrast agent, Gd(iii), was successfully encapsulated into 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-modified CNPs to form stable Gd(iii)-encapsulated CNPs (Gd(iii)-CNPs) with an average particle size of approximately 280 nm. The stable nanoparticle structure of Gd(iii)-CNPs is beneficial for liver tumor accumulation by the enhanced permeation and retention (EPR) effect. Moreover, the amine groups on the surface of Gd(iii)-CNPs could be protonated and could induce fast cellular uptake at acidic pH in tumor tissue. To assay the tumor-targeting ability of Cy5.5-labeled Gd(iii)-CNPs, near-infrared fluorescence (NIRF) imaging and MR imaging were used in a liver tumor model as well as a subcutaneous tumor model. Cy5.5-labeled Gd(iii)-CNPs generated highly intense fluorescence and T1 MR signals in tumor tissues after intravenous injection, while DOTAREM®, the commercialized control MR contrast agent, showed very low tumor-targeting efficiency on MR images. Furthermore, damaged tissues were found in the livers and kidneys of mice injected with DOTAREM®, but there were no obvious adverse effects with Gd(iii)-CNPs. Taken together, these results demonstrate the superiority of Gd(iii)-CNPs as a tumor-targeting T1 MR agent. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06673e

High-efficiency single cell encapsulation and size selective capture of cells in picoliter droplets based on hydrodynamic micro-vortices.

PubMed

Kamalakshakurup, Gopakumar; Lee, Abraham P

2017-12-05

Single cell analysis has emerged as a paradigm shift in cell biology to understand the heterogeneity of individual cells in a clone for pathological interrogation. Microfluidic droplet technology is a compelling platform to perform single cell analysis by encapsulating single cells inside picoliter-nanoliter (pL-nL) volume droplets. However, one of the primary challenges for droplet based single cell assays is single cell encapsulation in droplets, currently achieved either randomly, dictated by Poisson statistics, or by hydrodynamic techniques. In this paper, we present an interfacial hydrodynamic technique which initially traps the cells in micro-vortices, and later releases them one-to-one into the droplets, controlled by the width of the outer streamline that separates the vortex from the flow through the streaming passage adjacent to the aqueous-oil interface (d gap ). One-to-one encapsulation is achieved at a d gap equal to the radius of the cell, whereas complete trapping of the cells is realized at a d gap smaller than the radius of the cell. The unique feature of this technique is that it can perform 1. high efficiency single cell encapsulations and 2. size-selective capturing of cells, at low cell loading densities. Here we demonstrate these two capabilities with a 50% single cell encapsulation efficiency and size selective separation of platelets, RBCs and WBCs from a 10× diluted blood sample (WBC capture efficiency at 70%). The results suggest a passive, hydrodynamic micro-vortex based technique capable of performing high-efficiency single cell encapsulation for cell based assays.

Preparation and modification of N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride nanoparticle as a protein carrier.

PubMed

Xu, Yongmei; Du, Yumin; Huang, Ronghua; Gao, Leping

2003-12-01

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is water-soluble derivative of chitosan (CS), synthesized by the reaction between glycidyl-trimethyl-ammonium chloride and CS. HTCC nanoparticles have been formed based on ionic gelation process of HTCC and sodium tripolyphosphate (TPP). Bovine serum albumin (BSA), as a model protein drug, was incorporated into the HTCC nanoparticles. HTCC nanoparticles were 110-180 nm in size, and their encapsulation efficiency was up to 90%. In vitro release studies showed a burst effect and a slow and continuous release followed. Encapsulation efficiency was obviously increased with increase of initial BSA concentration. Increasing TPP concentration from 0.5 to 0.7 mg/ml promoted encapsulation efficiency from 46.7% to 90%, and delayed release. As for modified HTCC nanoparticles, adding polyethylene glycol (PEG) or sodium alginate obviously decreased the burst effect of BSA from 42% to 18%. Encapsulation efficiency was significantly reduced from 47.6% to 2% with increase of PEG from 1.0 to 20.0 mg/ml. Encapsulation efficiency was increased from 14.5% to 25.4% with increase of alginate from 0.3 to 1.0 mg/ml.

Encapsulation of adenovirus serotype 5 in anionic lecithin liposomes using a bead-based immunoprecipitation technique enhances transfection efficiency.

PubMed

Mendez, Natalie; Herrera, Vanessa; Zhang, Lingzhi; Hedjran, Farah; Feuer, Ralph; Blair, Sarah L; Trogler, William C; Reid, Tony R; Kummel, Andrew C

2014-11-01

Oncolytic viruses (OVs) constitute a promising class of cancer therapeutics which exploit validated genetic pathways known to be deregulated in many cancers. To overcome an immune response and to enhance its potential use to treat primary and metastatic tumors, a method for liposomal encapsulation of adenovirus has been developed. The encapsulation of adenovirus in non-toxic anionic lecithin-cholesterol-PEG liposomes ranging from 140 to 180 nm in diameter have been prepared by self-assembly around the viral capsid. The encapsulated viruses retain their ability to infect cancer cells. Furthermore, an immunoprecipitation (IP) technique has shown to be a fast and effective method to extract non-encapsulated viruses and homogenize the liposomes remaining in solution. 78% of adenovirus plaque forming units were encapsulated and retained infectivity after IP processing. Additionally, encapsulated viruses have shown enhanced transfection efficiency up to 4 × higher compared to non-encapsulated Ads. Extracting non-encapsulated viruses from solution may prevent an adverse in vivo immune response and may enhance treatment for multiple administrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Encapsulation of Adenovirus Serotype 5 in Anionic Lecithin Liposomes using a Bead-Based Immunoprecipitation Technique Enhances Transfection Efficiency

PubMed Central

Mendez, N.; Herrera, V.; Zhang, L.; Hedjran, F.; Feuer, R.; Blair, S.; Trogler, W.; Reid, T.

2014-01-01

Oncolytic viruses (OVs) constitute a promising class of cancer therapeutics which exploit validated genetic pathways known to be deregulated in many cancers. To overcome an immune response and to enhance its potential use to treat primary and metastatic tumors, a method for liposomal encapsulation of adenovirus has been developed. The encapsulation of adenovirus in non-toxic anionic lecithin-cholesterol-PEG liposomes ranging from 140–180nm in diameter have been prepared by self-assembly around the viral capsid. The encapsulated viruses retain their ability to infect cancer cells. Furthermore, an immunoprecipitation (IP) technique has shown to be a fast and effective method to extract non-encapsulated viruses and homogenize the liposomes remaining in solution. 78% of adenovirus plaque forming units were encapsulated and retained infectivity after IP processing. Additionally, encapsulated viruses have shown enhanced transfection efficiency up to 4× higher compared to non-encapsulated Ads. Extracting non-encapsulated viruses from solution may prevent an adverse in vivo immune response and may enhance treatment for multiple administrations. PMID:25154663

Encapsulation optimization of lemon balm antioxidants in calcium alginate hydrogels.

PubMed

Najafi-Soulari, Samira; Shekarchizadeh, Hajar; Kadivar, Mahdi

2016-11-01

Calcium alginate hydrogel beads were used to encapsulate lemon balm extract. Chitosan layer was used to investigate the effect of hydrogel coating. To determine the interactions of antioxidant compounds of extract with encapsulation materials and its stability, microstructure of hydrogel beads was thoroughly monitored using scanning electron microscopy and Fourier transform infrared (FTIR). Total polyphenols content and antiradical activity of lemon balm extract were also evaluated before and after encapsulation. Three significant parameters (lemon balm extract, sodium alginate, and calcium chloride concentrations) were optimized by response surface methodology to obtain maximum encapsulation efficiency. The FTIR spectra showed no interactions between extract and polymers as there were no new band in spectra of alginate hydrogel after encapsulation of active compounds of lemon balm extract. The antioxidant activity of lemon balm extract did not change after encapsulation. Therefore, it was found that alginate is a suitable material for encapsulation of natural antioxidants. Sodium alginate solution concentration, 1.84%, lemon balm extract concentration, 0.4%, and calcium chloride concentration, 0.2% was determined to be the optimum condition to reach maximum encapsulation efficiency.

Self-assembly of amphiphilic janus particles into monolayer capsules for enhanced enzyme catalysis in organic media.

PubMed

Cao, Wei; Huang, Renliang; Qi, Wei; Su, Rongxin; He, Zhimin

2015-01-14

Encapsulation of enzymes during the creation of an emulsion is a simple and efficient route for enhancing enzyme catalysis in organic media. Herein, we report a capsule with a shell comprising a monolayer of silica Janus particles (JPs) (referred to as a monolayer capsule) and a Pickering emulsion for the encapsulation of enzyme molecules for catalysis purposes in organic media using amphiphilic silica JPs as building blocks. We demonstrate that the JP capsules had a monolayer shell consisting of closely packed silica JPs (270 nm). The capsules were on average 5-50 μm in diameter. The stability of the JP capsules (Pickering emulsion) was investigated with the use of homogeneous silica nanoparticles as a control. The results show that the emulsion stabilized via amphiphilic silica JPs presented no obvious changes in physical appearance after 15 days, indicating the high stability of the emulsions and JP capsules. Furthermore, the lipase from Candida sp. was chosen as a model enzyme for encapsulation within the JP capsules during their formation. The catalytic performance of lipase was evaluated according to the esterification of 1-hexanol with hexanoic acid. It was found that the specific activity of the encapsulated enzymes (28.7 U mL(-1)) was more than 5.6 times higher than that of free enzymes in a biphasic system (5.1 U mL(-1)). The enzyme activity was further increased by varying the volume ratio of water to oil and the JPs loadings. The enzyme-loaded capsule also exhibited high stability during the reaction process and good recyclability. In particular, the jellification of agarose in the JP capsules further enhanced their operating stability. We believe that the monolayer structure of the JP capsules, together with their high stability, rendered the capsules to be ideal enzyme carriers and microreactors for enzyme catalysis in organic media because they created a large interfacial area and had low mass transfer resistance through the monolayer shell.

Encapsulated cell bioremediation: Evaluation on the basis of particle tracer tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrich, C.R.; Stormo, K.E.; Ralston, D.R.

1998-09-01

Microencapsulation of degradative organisms enhances microorganism survivability. The use of encapsulated cell microbeads for in situ biodegradation depends not only on microorganism survival but also on microbead transport characteristics. Two forced-gradient, recirculating-loop tracer experiments were conducted to evaluate the feasibility of encapsulated cell transport and bioremediation on the basis of polystyrene microsphere transport results. The tracer tests were conducted in a shallow, confined, unconsolidated, heterogeneous, sedimentary aquifer using bromide ion and 2 {micro}m, 5 {micro}m, and 15{micro}m microsphere tracers. Significant differences were observed in the transport of bromide solute and polystyrene microspheres. Microspheres reached peak concentrations in monitoring wells beforemore » bromide, which was thought to reflect the influence of aquifer heterogeneity. Greater decreases in microsphere C/C{sub 0} ratios were observed with distance from the injection wells than in bromide C/C{sub 0} ratios, which was attributed to particle filtration and/or settling. Several methods might be considered for introducing encapsulated cell microbeads into a subsurface environment, including direct injection into a contaminated aquifer zone, injection through a recirculating ground water flow system, or emplacement in a subsurface microbial curtain in advance of a plume. However, the in situ use of encapsulated cells in an aquifer is probably limited to aquifers containing sufficiently large pore spaces, allowing passage of at least some encapsulated cells. The use of encapsulated cells may also be limited by differences in solute and microbead transport patterns and flowpath clogging by larger encapsulated cell microbeads.« less

Encapsulation of Volatile Citronella Essential Oil by Coacervation: Efficiency and Release Study

NASA Astrophysics Data System (ADS)

Manaf, M. A.; Subuki, I.; Jai, J.; Raslan, R.; Mustapa, A. N.

2018-05-01

The volatile citronella essential oil was encapsulated by simple coacervation and complex coacervation using Arabic gum and gelatin as wall material. Glutaraldehyde was used in the methodology as crosslinking agent. The citronella standard calibration graph obtained with R2 of 0.9523 was used for the accurate determination of encapsulation efficiency and release study. The release kinetic was analysed based on Fick"s law of diffusion for polymeric system and linear graph of Log fraction release over Log time was constructed to determine the release rate constant, k and diffusion coefficient, n. Both coacervation methods in the present study produce encapsulation efficiency around 94%. The produced capsules for both coacervation processes were discussed based on the capsules morphology and release kinetic mechanisms.

Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system.

PubMed

Katuwavila, Nuwanthi P; Perera, A D L C; Dahanayake, Damayanthi; Karunaratne, V; Amaratunga, Gehan A J; Karunaratne, D Nedra

2016-11-20

A novel, efficient delivery system for iron (Fe 2+ ) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30nm and with a negative zeta potential (-38mV). The in vitro release studies showed a prolonged release profile for 96h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2.The initial burst release upto 8h followed zero order kinetics at all three pH values. All the release profiles beyond 8h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel cyclodextrin nanosponges for delivery of calcium in hyperphosphatemia.

PubMed

Shende, Pravin; Deshmukh, Kiran; Trotta, Fransesco; Caldera, Fabrizio

2013-11-01

Cyclodextrin nanosponges are solid, porous nanoparticulate three dimensional structures, have been used as delivery system of different drugs. In this work, new cyclodextrin-based nanosponges of calcium carbonate were prepared by polymer condensation method to release the calcium in controlled manner in the treatment of hyperphosphatemia as novel carriers. SEM measurements revealed their roughly spherical shape, porous nature and mean particle size of about 400 nm. Zeta potentials of the nanosponges were sufficiently high to obtain stable formulations. The encapsulation efficiencies of calcium in nanosponge formulations were found to be 81-95%. The moisture contents of the nanosponges were in the range of 0.1-0.7%. The optimized formulation produces enteric and controlled release kinetics of calcium in the management and treatment of hyperphosphatemia. It was also observed that calcium ions bound efficiently to free phosphate in a pH-dependent fashion especially at pH 7. In accelerated stability study no significant changes occurred in physical appearance, size and nature of drug in formulation for 3 months. The results of FTIR and DSC confirmed that calcium carbonate was encapsulated in nanosponges structure. Copyright © 2013 Elsevier B.V. All rights reserved.

Bovine Serum Albumin Nanoparticles Containing Amphotericin B: Characterization, Cytotoxicity and In Vitro Antifungal Evaluation.

PubMed

Casa, Diani Meza; Karam, Thaysa Ksiaskiewcz; Alves, Aline de Cristo Soares; Zgoda, Aline Aparecida; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

2015-12-01

In this study, nanoparticles based on bovine serum albumin (BSA) containing amphotericin B (AmB) were obtained by the desolvation method and characterized with respect to size, size distribution, AmB encapsulation efficiency, AmB state of aggregation, and AmB in vitro release profile. After, the effect of nanoparticles on the cytotoxicity of human erythrocytes in vitro and efficacy over strains of Candida spp. were evaluated. The mean particle size was 156 nm and the AmB encapsulation efficiency was over 82%. The in vitro release profile revealed a sustained release of approximately 48% of AmB over 5 days. AmB is present in BSA nanoparticles as monomer. AmB-loaded nanoparticles showed very low index of hemolysis (less than 8%) in 72 h of assay compared to free AmB, which presented 100% of hemolysis in 2 h of incubation. The AmB-loaded BSA nanoparticles were as effective as free AmB against Candida albicans and Candida tropicalis, considering their sustained release profile. Thus, BSA nanoparticles are potential carriers for AmB, reducing its molecular aggregation and prolonging its release, resulting in lower cytotoxicity while maintaining its antifungal activity.

Protein encapsulation and release from PEO-b-polyphosphoester templated calcium carbonate particles.

PubMed

Ergul Yilmaz, Zeynep; Cordonnier, Thomas; Debuigne, Antoine; Calvignac, Brice; Jerome, Christine; Boury, Frank

2016-11-20

Calcium carbonate particles are promising candidates as proteins carriers for their controlled delivery in the body. The present paper aims at investigating the protein encapsulation by in situ precipitation of calcium carbonate particles prepared by a process based on supercritical CO 2 and using a new type of degradable well-defined double hydrophilic block copolymers composed of poly(ethylene oxide) and polyphosphoester blocks acting as templating agent for the calcium carbonate. For this study, lysozyme was chosen as a model for therapeutic protein for its availability and ease of detection. It was found that by this green process, loading into the CaCO 3 microparticles with a diameter about 2μm can be obtained as determined by scanning electron microscopy. A protein loading up to 6.5% active lysozyme was measured by a specific bioassay (Micrococcus lysodeikticus). By encapsulating fluorescent-labelled lysozyme (lysozyme-FITC), the confocal microscopy images confirmed its encapsulation and suggested a core-shell distribution of lysozyme into CaCO 3 , leading to a release profile reaching a steady state at 59% of release after 90min. Copyright © 2016. Published by Elsevier B.V.

Controlled Release from Core-Shell Nanoporous Silica Particles for Corrosion Inhibition of Aluminum Alloys

DOE PAGES

Jiang, Xingmao; Jiang, Ying-Bing; Liu, Nanguo; ...

2011-01-01

Ceriumore » m (Ce) corrosion inhibitors were encapsulated into hexagonally ordered nanoporous silica particles via single-step aerosol-assisted self-assembly. The core/shell structured particles are effective for corrosion inhibition of aluminum alloy AA2024-T3. Numerical simulation proved that the core-shell nanostructure delays the release process. The effective diffusion coefficient elucidated from release data for monodisperse particles in water was 1.0 × 10 − 14  m 2 s for Ce 3+ compared to 2.5 × 10 − 13  m 2 s for NaCl. The pore size, pore surface chemistry, and the inhibitor solubility are crucial factors for the application. Microporous hydrophobic particles encapsulating a less soluble corrosion inhibitor are desirable for long-term corrosion inhibition.« less

Gas-Phase Combustion Synthesis of Nonoxide Nanoparticles in Microgravity

NASA Technical Reports Server (NTRS)

Axelbaum, R. L.; Kumfer, B. M.; Sun, Z.; Chao, B. H.

2001-01-01

Gas-phase combustion synthesis is a promising process for creating nanoparticles for the growing nanostructure materials industry. The challenges that must be addressed are controlling particle size, preventing hard agglomerates, maintaining purity, and, if nonoxides are synthesized, protecting the particles from oxidation and/or hydrolysis during post-processing. Sodium-halide Flame Encapsulation (SFE) is a unique methodology for producing nonoxide nanoparticles that addresses these challenges. This flame synthesis process incorporates sodium and metal-halide chemistry, resulting in nanoparticles that are encapsulated in salt during the early stages of their growth in the flame. Salt encapsulation has been shown to allow control of particle size and morphology, while serving as an effective protective coating for preserving the purity of the core particles. Metals and compounds that have been produced using this technology include Al, W, Ti, TiB2, AlN, and composites of W-Ti and Al-AlN. Oxygen content in SFE synthesized nano- AlN has been measured by neutron activation analysis to be as low as 0.54wt.%, as compared to over 5wt.% for unprotected AlN of comparable size. The overall objective of this work is to study the SFE process and nano-encapsulation so that they can be used to produce novel and superior materials. SFE experiments in microgravity allow the study of flame and particle dynamics without the influence of buoyancy forces. Spherical sodium-halide flames are produced in microgravity by ejecting the halide from a spherical porous burner into a quiescent atmosphere of sodium vapor and argon. Experiments are performed in the 2.2 sec Drop Tower at the NASA-Glenn Research Center. Numerical models of the flame and particle dynamics were developed and are compared with the experimental results.

Stability of lipid encapsulated ferulic acid particles

USDA-ARS?s Scientific Manuscript database

Encapsulation of bioactive compounds by a solid lipid matrix provides stability and a mechanism for controlled release in formulated products. Phenolic compounds exhibit antioxidant and antimicrobial activities and have applications as functional food and feed additives. Ferulic acid, a common pheno...

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics.

PubMed

Ahmed, Osama A A; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid-liquid phase separation method, according to the Box-Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance.

Preparation methods for monodispersed garlic oil microspheres in water using the microemulsion technique and their potential as antimicrobials.

PubMed

Zheng, Hua Ming; Li, Hou Bin; Wang, Da Wei; Liu, Dun

2013-08-01

Garlic oil is considered as a natural broad-spectrum antibiotic because of its well-known antimicrobial activity. However, the characteristics of easy volatility and poor aqueous solubility limit the application of garlic oil in industry. The purpose of the present work is to develop and evaluate an oil-free microemulsion by loading garlic oil in microemulsion system. Microemulsions were prepared with ethoxylated hydrogenated castor (Cremophor RH40) as surfactant, n-butanol (or ethanol) as cosurfactant, oleic acid-containing garlic oil as oil phase, and ultrapure water as water phase. The effects of the ratio of surfactant to cosurfactant and different oil concentration on the area of oil-in-water (O/W) microemulsion region in pseudoternary phase diagrams were investigated. The particle size and garlic oil encapsulation efficiency of the formed microemulsions with different formulations were also investigated. In addition, the antimicrobial activity in vitro against Escherichia coli and Staphylococcus aureus was assessed. The experimental results show that a stable microemulsion region can be obtained when the mass ratio of surfactant to cosurfactant is, respectively, 1:1, 2:1, and 3:1. Especially, when the mixture surfactants of RH40/n-butanol 2/1 (w/w) is used in the microemulsion formulation, the area of O/W microemulsion region is 0.089 with the particle size 13.29 to 13.85 nm and garlic oil encapsulation efficiency 99.5%. The prepared microemulsion solution exhibits remarkable antibacterial activity against S. aureus. © 2013 Institute of Food Technologists®

Influence of some formulation variables on the optimization of pH-dependent, colon-targeted, sustained-release mesalamine microspheres.

PubMed

El-Bary, Ahmed Abd; Aboelwafa, Ahmed A; Al Sharabi, Ibrahim M

2012-03-01

The aim of this work was to understand the influence of different formulation variables on the optimization of pH-dependent, colon-targeted, sustained-release mesalamine microspheres prepared by O/O emulsion solvent evaporation method, employing pH-dependent Eudragit S and hydrophobic pH-independent ethylcellulose polymers. Formulation variables studied included concentration of Eudragit S in the internal phase and the ratios between; internal to external phase, drug to Eudragit S and Eudragit S to ethylcellulose to mesalamine. Prepared microspheres were evaluated by carrying out in vitro release studies and determination of particle size, production yield, and encapsulation efficiency. In addition, morphology of microspheres was examined using optical and scanning electron microscopy. Emulsion solvent evaporation method was found to be sensitive to the studied formulation variables. Particle size and encapsulation efficiency increased by increasing Eudragit S concentration in the internal phase, ratio of internal to external phase, and ratio of Eudragit S to the drug. Employing Eudragit S alone in preparation of the microspheres is only successful in forming acid-resistant microspheres with pulsatile release pattern at high pH. Eudragit S and ethylcellulose blend microspheres were able to control release under acidic condition and to extend drug release at high pH. The stability studies carried out at 40°C/75% RH for 6 months proved the stability of the optimized formulation. From the results of this investigation, microencapsulation of mesalamine in microspheres using blend of Eudragit S and ethylcellulose could constitute a promising approach for site-specific and controlled delivery of drug in colon.

Effect of drug loading method against drug dissolution mechanism of encapsulated amoxicillin trihydrate in matrix of semi-IPN chitosan-poly(N-vinylpyrrolidone) hydrogel with KHCO3 as pore forming agent in floating drug delivery system

NASA Astrophysics Data System (ADS)

Fimantari, Khansa; Budianto, Emil

2018-04-01

Helicobacterpylori infection can be treated using trihydrate amoxicillin. However, this treatment is not effective enough, as the conventional dosage treatment has a relatively short retention time in the human stomach. In the present study, the amoxicillin trihydrate drug will be encapsulated into a semi-IPN K-PNVP hydrogel matrix with 7,5% KHCO3 as a pore-forming agent. The encapsulated drug is tested with in vitro method to see the efficiency of its encapsulation and dissolution. The hydrogel in situ loading produces an encapsulation efficiency value. The values of the encapsulation efficiency are 95% and 98%, while post loading hydrogel yields an encapsulation efficiency value is 77% and the dissolution is 84%. The study of drug dissolution mechanism was done by using mathematical equation model to know its kinetics and its mechanism of dissolution. The post loading hydrogel was done by using thefirst-order model, while hydrogel in situ loading used Higuchi model. The Korsmeyer-Peppas model shows that post loading hydrogel dissolution mechanism is a mixture of diffusion and erosion, and in situ loading hydrogel in the form of diffusion. It is supported by the results of hydrogel characterization, before and after dissolution test with an optical microscope. The results of the optical microscope show that the hydrogel surface before and after the dissolution tested for both methods shows the change becomes rougher.

Binary particle separation in droplet microfluidics using acoustophoresis

NASA Astrophysics Data System (ADS)

Fornell, Anna; Cushing, Kevin; Nilsson, Johan; Tenje, Maria

2018-02-01

We show a method for separation of two particle species with different acoustic contrasts originally encapsulated in the same droplet in a continuous two-phase system. This was realized by using bulk acoustic standing waves in a 380 μm wide silicon-glass microfluidic channel. Polystyrene particles (positive acoustic contrast particles) and in-house synthesized polydimethylsiloxane (PDMS) particles (negative acoustic contrast particles) were encapsulated inside water-in-oil droplets either individually or in a mixture. At acoustic actuation of the system at the fundamental resonance frequency, the polystyrene particles were moved to the center of the droplet (pressure node), while the PDMS particles were moved to the sides of the droplet (pressure anti-nodes). The acoustic particle manipulation step was combined in series with a trifurcation droplet splitter, and as the original droplet passed through the splitter and was divided into three daughter droplets, the polystyrene particles were directed into the center daughter droplet, while the PDMS particles were directed into the two side daughter droplets. The presented method expands the droplet microfluidics tool-box and offers new possibilities to perform binary particle separation in droplet microfluidic systems.

Optofluidic encapsulation and manipulation of silicon microchips using image processing based optofluidic maskless lithography and railed microfluidics.

PubMed

Chung, Su Eun; Lee, Seung Ah; Kim, Jiyun; Kwon, Sunghoon

2009-10-07

We demonstrate optofluidic encapsulation of silicon microchips using image processing based optofluidic maskless lithography and manipulation using railed microfluidics. Optofluidic maskless lithography is a dynamic photopolymerization technique of free-floating microstructures within a fluidic channel using spatial light modulator. Using optofluidic maskless lithography via computer-vision aided image processing, polymer encapsulants are fabricated for chip protection and guiding-fins for efficient chip conveying within a fluidic channel. Encapsulated silicon chips with guiding-fins are assembled using railed microfluidics, which is an efficient guiding and heterogeneous self-assembly system of microcomponents. With our technology, externally fabricated silicon microchips are encapsulated, fluidically guided and self-assembled potentially enabling low cost fluidic manipulation and assembly of integrated circuits.

Design and immunological evaluation of anti-CD205-tailored PLGA-based nanoparticulate cancer vaccine.

PubMed

Jahan, Sheikh Tasnim; Sadat, Sams Ma; Haddadi, Azita

2018-01-01

The aim of this research was to develop a targeted antigen-adjuvant assembled delivery system that will enable dendritic cells (DCs) to efficiently mature to recognize antigens released from tumor cells. It is important to target the DCs with greater efficiency to prime T cell immune responses. In brief, model antigen, ovalbumin (OV), and monophosphoryl lipid A adjuvant were encapsulated within the nanoparticle (NP) by double emulsification solvent evaporation method. Targeted NPs were obtained through ligand incorporation via physical adsorption or chemical conjugation process. Intracellular uptake of the NPs and the maturation of DCs were evaluated with flow cytometry. Remarkably, the developed delivery system had suitable physicochemical properties, such as particle size, surface charge, OV encapsulation efficiency, biphasic OV release pattern, and safety profile. The ligand modified formulations had higher targeting efficiency than the non-tailored NPs. This was also evident when the targeted formulations expressed comparatively higher fold increase in surface activation markers such as CD40, CD86, and major histocompatibility complex class II molecules. The maturation of DCs was further confirmed through secretion of extracellular cytokines compared to control cells in the DC microenvironment. Physicochemical characterization of NPs was performed based on the polymer end groups, their viscosities, and ligand-NP bonding type. In conclusion, the DC stimulatory response was integrated to develop a relationship between the NP structure and desired immune response. Therefore, the present study narrates a comparative evaluation of some selected parameters to choose a suitable formulation useful for in vivo cancer immunotherapy.

Development of magnetic separation system of magnetoliposomes

NASA Astrophysics Data System (ADS)

Nakao, R.; Matuo, Y.; Mishima, F.; Taguchi, T.; Maenosono, S.; Nishijima, S.

2009-10-01

The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe 3O 4 of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe 3O 4 encapsulated with phospholipid liposomes of 200 nm in diameter was also shown to be trapped as external magnetic field of 1.5 T, but not of 0.5 T. We also showed the result of particle trajectory calculation which emulated well the experimental data.

KSC-97PC1232

NASA Image and Video Library

1997-08-13

In KSC’s Spacecraft Assembly and Encapsulation Facility-II (SAEF-II), the Advanced Composition Explorer (ACE) spacecraft is encapsulated and placed into the transporter which will move it to Launch Complex 17A. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 24, ACE will study low-energy particles of solar origin and high-energy galactic particles. The collecting power of instruments aboard ACE is 10 to 1,000 times greater than anything previously flown to collect similar data by NASA

KSC-97PC1234

NASA Image and Video Library

1997-08-13

In KSC’s Spacecraft Assembly and Encapsulation Facility-II (SAEF-II), the Advanced Composition Explorer (ACE) spacecraft is encapsulated and placed into the transporter which will move it to Launch Complex 17A. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 24, ACE will study low-energy particles of solar origin and high-energy galactic particles. The collecting power of instruments aboard ACE is 10 to 1,000 times greater than anything previously flown to collect similar data by NASA

A New Self-Consistent Field Model of Polymer/Nanoparticle Mixture

NASA Astrophysics Data System (ADS)

Chen, Kang; Li, Hui-Shu; Zhang, Bo-Kai; Li, Jian; Tian, Wen-De

2016-02-01

Field-theoretical method is efficient in predicting assembling structures of polymeric systems. However, it’s challenging to generalize this method to study the polymer/nanoparticle mixture due to its multi-scale nature. Here, we develop a new field-based model which unifies the nanoparticle description with the polymer field within the self-consistent field theory. Instead of being “ensemble-averaged” continuous distribution, the particle density in the final morphology can represent individual particles located at preferred positions. The discreteness of particle density allows our model to properly address the polymer-particle interface and the excluded-volume interaction. We use this model to study the simplest system of nanoparticles immersed in the dense homopolymer solution. The flexibility of tuning the interfacial details allows our model to capture the rich phenomena such as bridging aggregation and depletion attraction. Insights are obtained on the enthalpic and/or entropic origin of the structural variation due to the competition between depletion and interfacial interaction. This approach is readily extendable to the study of more complex polymer-based nanocomposites or biology-related systems, such as dendrimer/drug encapsulation and membrane/particle assembly.

Stability of lipid encapsulated phenolic acid particles

USDA-ARS?s Scientific Manuscript database

Phenolic compounds such as ferulic acid and p-coumaric acids are potential bioactive additives for use in animal feeds to replace current antioxidants and antimicrobial compounds. These compounds are ubiquitous in plants and may be obtained from commodity grain crops and waste biomass. Encapsulation...

Molecular Level Coating of Metal Oxide Particles

NASA Technical Reports Server (NTRS)

McDaniel, Patricia R. (Inventor); St.Clair, Terry L. (Inventor)

2002-01-01

Polymer encapsulated metal oxide particles are prepared by combining a polyamide acid in a polar osmotic solvent with a metal alkoxide solution. The polymer was imidized and the metal oxide formed simultaneously in a refluxing organic solvent. The resulting polymer-metal oxide is an intimately mixed commingled blend, possessing, synergistic properties of both the polymer and preceramic metal oxide. The encapsulated metal oxide particles have multiple uses including, being useful in the production of skin lubricating creams, weather resistant paints, as a filler for paper. making ultraviolet light stable filled printing ink, being extruded into fibers or ribbons, and coatings for fibers used in the production of composite structural panels.

Molecular Level Coating for Metal Oxide Particles

NASA Technical Reports Server (NTRS)

McDaniel, Patricia R. (Inventor); Saint Clair, Terry L. (Inventor)

2000-01-01

Polymer encapsulated metal oxide particles are prepared by combining a polyamide acid in a polar aprotic solvent with a metal alkoxide solution. The polymer was imidized and the metal oxide formed simultaneously in a refluxing organic solvent. The resulting polymer-metal oxide is an intimately mixed commingled blend, possessing synergistic properties of both the polymer and preceramic metal oxide. The encapsulated metal oxide particles have multiple uses including, being useful in the production of skin lubricating creams, weather resistant paints, as a filler for paper, making ultraviolet light stable filled printing ink, being extruded into fibers or ribbons, and coatings for fibers used in the production of composite structural panels.

Particle Manipulation Methods in Droplet Microfluidics.

PubMed

Tenje, Maria; Fornell, Anna; Ohlin, Mathias; Nilsson, Johan

2018-02-06

This Feature describes the different particle manipulation techniques available in the droplet microfluidics toolbox to handle particles encapsulated inside droplets and to manipulate whole droplets. We address the advantages and disadvantages of the different techniques to guide new users.

Characterization and Antilisterial Effect of Phosphatidylcholine Nanovesicles Containing the Antimicrobial Peptide Pediocin.

PubMed

de Mello, Michele Brauner; da Silva Malheiros, Patrícia; Brandelli, Adriano; Pesce da Silveira, Nádya; Jantzen, Márcia Monks; de Souza da Motta, Amanda

2013-03-01

Encapsulation may provide increased stability and antimicrobial efficiency to bacteriocins. In this work, the antilisterial peptide pediocin was encapsulated in nanovesicles prepared from partially purified soybean phosphatidylcholine. The maintenance of antimicrobial activity and properties of free and encapsulated pediocin was observed during 13 days at 4 °C, and after this period, the encapsulated pediocin retained 50 % its initial activity. The maintenance of the bioactive properties of free and encapsulated pediocin was observed against different species of Listeria, inhibiting Listeria monocytogenes, Listeria innocua and Listeria ivanovii. The size of vesicles containing pediocin was determined by dynamic light scattering as an average of 190 nm, with little change throughout the observation period. Polydispersity index values were around 0.201 and are considered satisfactory, indicating an adequate size distribution of liposomes. The efficiency of encapsulation was 80 %. Considering these results, the protocol used was appropriate for the encapsulation of this bacteriocin. Results demonstrate the production of stable nanoparticulate material. The maintenance of the properties of pediocin encapsulated in liposomes is fundamental to prospect the stability in different conditions of the food matrix.

Engineering of budesonide-loaded lipid-polymer hybrid nanoparticles using a quality-by-design approach.

PubMed

Leng, Donglei; Thanki, Kaushik; Fattal, Elias; Foged, Camilla; Yang, Mingshi

2017-08-25

Chronic obstructive pulmonary disease (COPD) is a complex disease, characterized by persistent airflow limitation and chronic inflammation. The purpose of this study was to design lipid-polymer hybrid nanoparticles (LPNs) loaded with the corticosteroid, budesonide, which could potentially be combined with small interfering RNA (siRNA) for COPD management. Here, we prepared LPNs based on the biodegradable polymer poly(dl-lactic-co-glycolic acid) (PLGA) and the cationic lipid dioleyltrimethylammonium propane (DOTAP) using a double emulsion solvent evaporation method. A quality-by-design (QbD) approach was adopted to define the optimal formulation parameters. The quality target product profile (QTPP) of the LPNs was identified based on risk assessment. Two critical formulation parameters (CFPs) were identified, including the theoretical budesonide loading and the theoretical DOTAP loading. The CFPs were linked to critical quality attributes (CQAs), which included the intensity-based hydrodynamic particle diameter (z-average), the polydispersity index (PDI), the zeta-potential, the budesonide encapsulation efficiency, the actual budesonide loading and the DOTAP encapsulation efficiency. A response surface methodology (RSM) was applied for the experimental design to evaluate the influence of the CFPs on the CQAs, and to identify the optimal operation space (OOS). All nanoparticle dispersions displayed monodisperse size distributions (PDI<0.2) with z-averages of approximately 150nm, suggesting that the size is not dependent on the investigated CFPs. In contrast, the zeta-potential was highly dependent on the theoretical DOTAP loading. Upon increased DOTAP loading, the zeta-potential reached a maximal point, after which it remained stable at the maximum value. This suggests that the LPN surface is covered by DOTAP, and that the DOTAP loading is saturable. The actual budesonide loading of the LPNs was mainly dependent on the initial amount of budesonide, and a clear positive effect was observed, which shows that the interaction between drug and PLGA increases when increasing the initial amount of budesonide. The OOS was modeled by applying the QTPP. The OOS had a budesonide encapsulation efficiency higher than 30%, a budesonide loading above 15μg budesonide/mg PLGA, a zeta-potential higher than 35mV and a DOTAP encapsulation efficiency above 50%. This study shows the importance of systematic formulation design for understanding the effect of formulation parameters on the characteristics of LPNs, eventually resulting in the identification of an OOS. Copyright © 2017 Elsevier B.V. All rights reserved.

[Optimization of Formulation and Process of Paclitaxel PEGylated Liposomes by Box-Behnken Response Surface Methodology].

PubMed

Shi, Ya-jun; Zhang, Xiao-feil; Guo, Qiu-ting

2015-12-01

To develop a procedure for preparing paclitaxel encapsulated PEGylated liposomes. The membrane hydration followed extraction method was used to prepare PEGylated liposomes. The process and formulation variables were optimized by "Box-Behnken Design (BBD)" of response surface methodology (RSM) with the amount of Soya phosphotidylcholine (SPC) and PEG2000-DSPE as well as the rate of SPC to drug as independent variables and entrapment efficiency as dependent variables for optimization of formulation variables while temperature, pressure and cycle times as independent variables and particle size and polydispersion index as dependent variables for process variables. The optimized liposomal formulation was characterized for particle size, Zeta potential, morphology and in vitro drug release. For entrapment efficiency, particle size, polydispersion index, Zeta potential, and in vitro drug release of PEGylated liposomes was found to be 80.3%, (97.15 ± 14.9) nm, 0.117 ± 0.019, (-30.3 ± 3.7) mV, and 37.4% in 24 h, respectively. The liposomes were found to be small, unilamellar and spherical with smooth surface as seen in transmission electron microscopy. The Box-Behnken response surface methodology facilitates the formulation and optimization of paclitaxel PEGylated liposomes.

Protein encapsulation via porous CaCO3 microparticles templating.

PubMed

Volodkin, Dmitry V; Larionova, Natalia I; Sukhorukov, Gleb B

2004-01-01

Porous microparticles of calcium carbonate with an average diameter of 4.75 microm were prepared and used for protein encapsulation in polymer-filled microcapsules by means of electrostatic layer-by-layer assembly (ELbL). Loading of macromolecules in porous CaCO3 particles is affected by their molecular weight due to diffusion-limited permeation inside the particles and also by the affinity to the carbonate surface. Adsorption of various proteins and dextran was examined as a function of pH and was found to be dependent both on the charge of the microparticles and macromolecules. The electrostatic effect was shown to govern this interaction. This paper discusses the factors which can influence the adsorption capacity of proteins. A new way of protein encapsulation in polyelectrolyte microcapsules is proposed exploiting the porous, biocompatible, and decomposable microparticles from CaCO3. It consists of protein adsorption in the pores of the microparticles followed by ELbL of oppositely charged polyelectrolytes and further core dissolution. This resulted in formation of polyelectrolyte-filled capsules with protein incorporated in interpenetrating polyelectrolyte network. The properties of CaCO3 microparticles and capsules prepared were characterized by scanning electron microscopy, microelectrophoresis, and confocal laser scanning microscopy. Lactalbumin was encapsulated by means of the proposed technique yielding a content of 0.6 pg protein per microcapsule. Horseradish peroxidase saves 37% of activity after encapsulation. However, the thermostability of the enzyme was improved by encapsulation. The results demonstrate that porous CaCO3 microparticles can be applied as microtemplates for encapsulation of proteins into polyelectrolyte capsules at neutral pH as an optimal medium for a variety of bioactive material, which can also be encapsulated by the proposed method. Microcapsules filled with encapsulated material may find applications in the field of biotechnology, biochemistry, and medicine.

Preparation and Surface Property of Fluoroalkyl End-Capped Vinyltrimethoxysilane Oligomer/Talc Composite-Encapsulated Organic Compounds: Application for the Separation of Oil and Water.

PubMed

Oikawa, Yuri; Saito, Tomoya; Yamada, Satoshi; Sugiya, Masashi; Sawada, Hideo

2015-07-01

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R(F)-(CH2-CHSi(OMe)3)n-R(F); n = 2, 3; R(F) = CF(CF3)OC3F7 (R(F)-VM oligomer)] can undergo the sol-gel reaction in the presence of talc particles under alkaline conditions at room temperature to provide the corresponding fluorinated oligomeric silica/talc nanocomposites (RF-VM-SiO2/Talc). A variety of guest molecules such as 2-hydroxy-4-methoxybenzophenone (HMB), bisphenol A (BPA), bisphenol AF, 3-(hydroxysilyl)-1-propanesulfonic acid (THSP), and perfluoro-2-methyl-3-oxahexanoic acid (R(F)-COOH) are effectively encapsulated into the R(F)-VM-SiO2/Talc composite cores to afford the corresponding fluorinated nanocomposites-encapsulated these guest molecules. The R(F)-VM-SiO2/Talc composites encapsulated low molecular weight aromatic compounds such as HMB and BPA can exhibit a superoleophilic-superhydrophobic characteristic on the surfaces; however, the R(F)-VM-SiO2/Talc composite-encapsulated THSP and R(F)-COOH exhibit a superoleophobic-superhydrophilic characteristic on the modified surfaces. In these nanocomposites, the R(F)-VM-SiO2/Talc/THSP composites are applicable to the surface modification of polyester fabric, and the modified polyester fabric possessing a superoleophobic-superhydrophilic characteristic on the surface can be used for the membrane for oil (dodecane)/water separation. In addition, the R(F)-VM-SiO2/Talc composites-encapsulated micrometer-size controlled cross-linked polystyrene particles can be also prepared under similar conditions, and the obtained composite white-colored particle powders are applied to the packing material for the column chromatography to separate water-in-oil (W/O) emulsion.

Hypericin encapsulated in solid lipid nanoparticles: phototoxicity and photodynamic efficiency.

PubMed

Lima, Adriel M; Pizzol, Carine Dal; Monteiro, Fabíola B F; Creczynski-Pasa, Tânia B; Andrade, Gislaine P; Ribeiro, Anderson O; Perussi, Janice R

2013-08-05

The hydrophobicity of some photosensitizers can induce aggregation in biological systems, which consequently reduces photodynamic activity. The conjugation of photosensitizers with nanocarrier systems can potentially be used to overcome this problem. The objective of this study was to prepare and characterise hypericin-loaded solid lipid nanoparticles (Hy-SLN) for use in photodynamic therapy (PDT). SLN were prepared using the ultrasonication technique, and their physicochemical properties were characterised. The mean particle size was found to be 153 nm, with a low polydispersity index of 0.28. One of the major advantages of the SLN formulation is its high entrapment efficiency (EE%). Hy-SLN showed greater than 80% EE and a drug loading capacity of 5.22% (w/w). To determine the photodynamic efficiency of Hy before and after encapsulation in SLN, the rate constants for the photodecomposition of two (1)O2 trapping reagents, DPBF and AU, were determined. These rate constants exhibited an increase of 60% and 50% for each method, respectively, which is most likely due to an increase in the lifetime of the triplet state caused by the increase in solubility. Hy-SLN presented a 30% increase in cell uptake and a correlated improvement of 26% in cytotoxicity. Thus, all these advantages suggest that Hy-loaded SLN has potential for use in PDT. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluating the Properties of Poly(lactic-co-glycolic acid) Nanoparticle Formulations Encapsulating a Hydrophobic Drug by Using the Quality by Design Approach.

PubMed

Kozaki, Masato; Kobayashi, Shin-Ichiro; Goda, Yukihiro; Okuda, Haruhiro; Sakai-Kato, Kumiko

2017-01-01

We applied the Quality by Design (QbD) approach to the development of poly(lactic-co-glycolic acid) (PLGA) nanoparticle formulations encapsulating triamcinolone acetonide, and the critical process parameters (CPPs) were identified to clarify the correlations between critical quality attributes and CPPs. Quality risk management was performed by using an Ishikawa diagram and experiments with a fractional factorial design (ANOVA). The CPPs for particle size were PLGA concentration and rotation speed, and the CPP for relative drug loading efficiency was the poor solvent to good solvent volume ratio. By assessing the mutually related factors in the form of ratios, many factors could be efficiently considered in the risk assessment. We found a two-factor interaction between rotation speed and rate of addition of good solvent by using a fractional factorial design with resolution V. The system was then extended by using a central composite design, and the results obtained were visualized by using the response surface method to construct a design space. Our research represents a case study of the application of the QbD approach to pharmaceutical development, including formulation screening, by taking actual production factors into consideration. Our findings support the feasibility of using a similar approach to nanoparticle formulations under development. We could establish an efficient method of analyzing the CPPs of PLGA nanoparticles by using a QbD approach.

A Comparative Cytotoxic Evaluation of Disulfiram Encapsulated PLGA Nanoparticles on MCF-7 Cells.

PubMed

Fasehee, Hamidreza; Ghavamzadeh, Ardeshir; Alimoghaddam, Kamran; Ghaffari, Seyed-Hamidollah; Faghihi, Shahab

2017-04-01

Background: Disulfiram is oral aldehyde dehydrogenase (ALDH) inhibitor that has been used in the treatment of alcoholism. Recent studies show that this drug has anticancer properties; however, its rapid degradation has limited its clinical application. Encapsulation of disulfiram polymeric nanoparticles (NPs) may improve its anticancer activities and protect rapid degradation of the drug. Materials and Methods: A poly (lactide-co-Glycolide) (PLGA) was developed for encapsulation of disulfiram and its delivery into breast cancer cells. Disulfiram encapsulated PLGA NPs were prepared by nanoprecipitation method and were characterized by Scanning Electron Microscopy (SEM). The loading and encapsulation efficiency of NPs were determined using UV-Visible spectroscopy. Cell cytotoxicity of free and encapsulated form of disulfiram is also determined using MTT assay. Results: Disulfiram encapsulated PLGA NPs had uniform size with 165 nm. Drug loading and entrapment efficiency were 5.35 ±0.03% and 58.85±1.01%. The results of MTT assay showed that disulfiram encapsulated PLGA NPs were more potent in induction of apoptosis compare to free disulfiram. Conclusion: Based on the results obtained in the present study it can be concluded that encapsulation of disulfiram with PLGA can protect its degradation in improve its cytotoxicity on breast cancer cells.

Toroidal-spiral particles for codelivery of anti-VEGFR-2 antibody and irinotecan: a potential implant to hinder recurrence of glioblastoma multiforme.

PubMed

Sharma, Vishal; Köllmer, Melanie; Szymusiak, Magdalena; Nitsche, Ludwig C; Gemeinhart, Richard A; Liu, Ying

2014-03-10

Heterogeneous toroidal-spiral particles (TSPs) were generated by polymer droplet sedimentation, interaction, and cross-linking. TSPs provide a platform for encapsulation and release of multiple compounds of different sizes and physicochemical properties. As a model system, we demonstrate the encapsulation and independently controlled release of an anti-VEGFR-2 antibody and irinotecan for the treatment of glioblastoma multiforme. The anti-VEGFR-2 antibody was released from the TS channels and its binding to HUVECs was confirmed by confocal microscopy and flow cytometry, suggesting active antibody encapsulation and release. Irinotecan, a small molecule drug, was released from the dense polymer matrix of poly(ethylene glycol) diacrylate (MW ~ 700 g/mol; PEGDA 700). Released irinotecan inhibited the proliferation of U251 malignant glioma cells. Since the therapeutic compounds are released through different pathways, specifically diffusion through the polymer matrix versus TS channels, the release rate can be controlled independently through the design of the structure and material of particle components.

Development and optimization of doxorubicin loaded poly(lactic-co-glycolic acid) nanobubbles for drug delivery into HeLa cells.

PubMed

Deng, Liwei; Li, Li; Yang, Hong; Li, Li; Zhao, Fenglong; Wu, Chunhui; Liu, Yiyao

2014-04-01

Microbubbles (MBs, usually 2-8 microm) as ultrasound contrast agent and drug carrier are promising for ultrasonic imaging and drug delivery. However, MBs posed some limitations due to their large diameters. In the current study, we developed a nanoscale bubbles (nanobubbles, NBs) by encapsulating the doxorubicin (DOX) into poly(lactic-co-glycolic acid) (PLGA) shells (denoted as DOX-PLGA NBs) for drug delivery into cancer cells. The size, morphology, particle stability, drug encapsulation efficiency, and drug payload were determined. The results showed that the DOX-PLGA NBs were uniform (270 +/- 3 nm) and spherical with a smooth surface, and were well dispersed and stable in water. The encapsulation efficiency and payload of DOX increased with its initial loading concentrations. The release behavior of DOX from the DOX-PLGA NBs exhibited a biphasic pattern characterized by an initial burst release followed by a slower and continuous release at both pH 7.4 and pH 4.4, and also presented in a pH-triggered releasing profile. The qualitative analysis of cellular internalization into HeLa cells by inverted fluorescence microscope showed that the cellular uptake of DOX-PLGA NBs was both concentration- and time-dependent. Moreover, the cell viability was also investigated using CCK-8 assay. It was found that DOX-PLGA NBs showed greater HeLa cell growth inhibition effect in vitro compared with free DOX. It was concluded that the DOX-PLGA NBs were biocompatible and appropriate for anti-cancer drug delivery, and were potentially promising as a new therapeutic system for cancer treatment.

Release behavior and signaling effect of vitamin D3 in layered double hydroxides-hydroxyapatite/gelatin bone tissue engineering scaffold: An in vitro evaluation.

PubMed

Fayyazbakhsh, Fateme; Solati-Hashjin, Mehran; Keshtkar, Abbas; Shokrgozar, Mohammad Ali; Dehghan, Mohammad Mehdi; Larijani, Bagher

2017-10-01

Incorporating the controlled release of vitamin D3 (VD3) into biodegradable porous scaffolds is a new approach to equipping multifunctional therapeutics for osteoporosis. The current investigation involves the encapsulation of VD3 into gelatin through the one-step desolvation method. The layered double hydroxides-hydroxyapatite nanocomposite (LDH-HAp) and pure LDH were combined with the gelatin-VD3 complex to reinforce the porous biodegradable structure and enhance the biological response. Afterwards, glutaraldehyde was used to form crosslinks within the gelatin chains. The encapsulation efficiency and loading capacity showed approximately 40% and 50% reduction after crosslinking, respectively. The particle size, zeta potential, contact angle, Young's modulus and porosity were measured to find the effect of VD3 on the scaffolds' physiochemical properties. To explore the bioactivity and degradation behavior, the scaffolds were immersed in simulated body fluid. The VD3 release kinetics followed the Korsmeyer-Peppas model and non-Fickian release pattern. The greater osteblastic expression was observed in VD3-containing scaffolds due to the higher alkaline phosphatase activity which was excited more by HAp (P<0.05). Alizarin red staining illustrated that VD3 induced more calcium deposition, which indicates the signaling role of VD3 on osteoconductivity and biomineralization. The findings provide new insights on the VD3 encapsulation within hydrophilic matrices to protect VD3 and enable the signaling ability for bone tissue engineering scaffolds, which could improve the bone healing efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

Biological evaluation of N-2-hydroxypropyl trimethyl ammonium chloride chitosan as a carrier for the delivery of live Newcastle disease vaccine.

PubMed

Zhao, Kai; Sun, Yanwei; Chen, Gang; Rong, Guangyu; Kang, Hong; Jin, Zheng; Wang, Xiaohua

2016-09-20

Mucosal immune system plays a very important role in antiviral immune response. We prepared Newcastle disease viruses (NDV) encapsulated in N-2-hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) nanoparticles (NDV/La Sota-N-2-HACC-NPs) by an ionic cross linking method, and assessed the potential of N-2-HACC-NPs as a mucosal immune delivery carrier. The properties of the nanoparticles were determined by transmission electron microscopy, Zeta potential and particle size analysis, encapsulation efficiency and loading capacity. NDV/La Sota-N-2-HACC-NPs have regular spherical morphologies and high stability; with 303.88±49.8nm mean diameter, 45.77±0.75mV Zeta potential, 94.26±0.42% encapsulation efficiency and 54.06±0.21% loading capacity. In vitro release assay indicated that the release of NDV from NDV/La Sota-N-2-HACC-NPs is slow. The NDV/La Sota-N-2-HACC-NPs have good biological characteristics, very low toxicity and high level of safety. Additionally, specific pathogen-free chickens immunized with NDV/La Sota-N-2-HACC-NPs showed much stronger cellular, humoral and mucosal immune responses than commercial attenuated live Newcastle disease vaccine, and NDV/La Sota-N-2-HACC-NPs reached the sustainable release effect. Our study here provides a foundation for the further development of mucosal vaccines and drugs, and the N-2-HACC-NPs should be a potential drug delivery carrier with immense potential in medical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microneedle-assisted permeation of lidocaine carboxymethylcellulose with gelatine co-polymer hydrogel.

PubMed

Nayak, Atul; Das, Diganta B; Vladisavljević, Goran T

2014-05-01

Lidocaine hydrochloride (LidH) was formulated in sodium carboxymethyl cellulose/ gelatine (NaCMC/GEL) hydrogel and a 'poke and patch' microneedle delivery method was used to enhance permeation flux of LidH. The microparticles were formed by electrostatic interactions between NaCMC and GEL macromolecules within a water/oil emulsion in paraffin oil and the covalent crosslinking was by glutaraldehyde. The GEL to NaCMC mass ratio was varied between 1.6 and 2.7. The LidH encapsulation yield was 1.2 to 7% w/w. LidH NaCMC/GEL was assessed for encapsulation efficiency, zeta potential, mean particle size and morphology. Subsequent in vitro skin permeation studies were performed via passive diffusion and microneedle assisted permeation of LidH NaCMC/GEL to determine the maximum permeation rate through full thickness skin. LidH 2.4% w/w NaCMC/GEL 1:1.6 and 1:2.3 respectively, possessed optimum zeta potential. LidH 2.4% w/w NaCMC/GEL 1:2.3 and 1:2.7 demonstrate higher pseudoplastic behaviour. Encapsulation efficiency (14.9-17.2%) was similar for LidH 2.4% w/w NaCMC/GEL 1:1.6-1:2.3. Microneedle assisted permeation flux was optimum for LidH 2.4% w/w NaCMC/GEL 1:2.3 at 6.1 μg/ml/h. LidH 2.4% w/w LidH NaCMC/GEL 1:2.3 crossed the minimum therapeutic drug threshold with microneedle skin permeation in less than 70 min.

Effect of dynamic high pressure on emulsifying and encapsulant properties of cashew tree gum.

PubMed

Porto, Bruna Castro; Cristianini, Marcelo

2018-04-15

Dynamic high pressure (DHP) has been applied in the physical modification of biopolymers as polysaccharides, proteins and gums. It is known that DHP is able to promote degradation of polysaccharides (e.g. molecular weight reduction). However, few studies have assessed the effect of DHP on the emulsifying and encapsulating properties of polysaccharides. Thus, this study aimed to investigate the effect of DHP on the emulsifying (average droplet size and particle size distribution, optical and confocal scanning laser microscopy, rheology, zeta potential and electric conductivity, creaming index, and turbidity) and encapsulating (scanning electronic microscopy, flavor retention, average droplet size, and particle size distribution) properties of cashew tree gum (CG). The application of DHP process improved the emulsifying capacity of cashew tree gum (CG) by reducing the medium droplet size (D3,2 and D4,3), increasing the turbidity and improving the emulsion stability. However, no effect of DHP was observed on the encapsulating capacity of CG. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modified extrusion-spheronization as a technique of microencapsulation for stabilization of choline bitartrate using hydrogenated soya bean oil.

PubMed

Gangurde, Avinash Bhaskar; Sav, Ajay Kumar; Javeer, Sharadchandra Dagadu; Moravkar, Kailas K; Pawar, Jaywant N; Amin, Purnima D

2015-01-01

Choline bitartrate (CBT) is a vital nutrient for fetal brain development and memory function. It is hygroscopic in nature which is associated with stability related problem during storage such as development of fishy odor and discoloration. Microencapsulation method was adopted to resolve the stability problem and for this hydrogenated soya bean oil (HSO) was used as encapsulating agent. Industrially feasible modified extrusion-spheronization technique was selected for microencapsulation. HSO was used as encapsulating agent, hydroxypropyl methyl cellulose E5/E15 as binder and microcrystalline cellulose as spheronization aid. Formulated pellets were evaluated for parameters such as flow property, morphological characteristics, hardness-friability index (HFI), drug content, encapsulation efficiency, and in vitro drug release. The optimized formulations were also characterized for particle size (by laser diffractometry), differential scanning calorimetry, powder X-ray diffractometry (PXRD), Fourier transform infrared spectroscopy, and scanning electron microscopy. The results from the study showed that coating of 90% and 60% CBT was successful with respect to all desired evaluation parameters. Optimized formulation was kept for 6 months stability study as per ICH guidelines, and there was no change in color, moisture content, drug content, and no fishy odor was observed. Microencapsulated pellets of CBT using HSO as encapsulating agent were developed using modified extrusion spheronization technique. Optimized formulations, CBT 90% (F5), and CBT 60% (F10), were found to be stable for 4M and 6M, respectively, at accelerated conditions.

Thyrotropin-Releasing Hormone Loaded and Chitosan Engineered Polymeric Nanoparticles: Towards Effective Delivery of Neuropeptides.

PubMed

Kaur, Sarabjit; Bhararia, Avani; Sharma, Krishna; Mittal, Sherry; Jain, Rahul; Wangoo, Nishima; Sharma, Rohit K

2016-05-01

Thyrotropin-Releasing Hormone (TRH), a tripeptide amide with molecular formula L-pGlu-L-His-L- Pro-NH2, is used in the treatment of brain/spinal injury and certain central nervous system (CNS) disorders, including schizophrenia, Alzheimer's disease, epilepsy, depression, shock and ischemia due to its profound effects on the CNS. However, TRH's therapeutic activity is severely hampered because of instability and hydrophilicity owing to its peptidic nature which results into ineffective penetration into the blood brain barrier. In the present study, we report the synthesis and stability studies of novel chitosan engineered TRH encapsulated poly(lactide-co-glycolide) (PLGA) based nanoformulation. The aim of such an encapsulation is to allow effective delivery of TRH in biological systems as the peptidase degrade naked TRH. The synthesis of TRH was carried out manually in solution phase followed by its encapsulation using PLGA to form polymeric nanoparticles (NPs) via nanoprecipitation technique. Different parameters such as type of organic phase, concentration of stabilizer, ratio of organic phase and aqueous phase, rate of addition of organic phase were optimized, tested and evaluated for particle size, encapsulation efficiency, and stability of NPs. The TRH-PLGA NPs were then surface modified with chitosan to achieve positive surface charge rendering them potential membrane penetrating agents. PLGA, PLGA-TRH, Chitosan-PLGA and Chitosan-PLGA-TRH NPs were characterized and analyzed using Dynamic Light Scattering (DLS), Transmissiom Electron Microscopy (TEM) and Infra-red spectroscopic techniques.

Optimization and physicochemical characterization of a cationic lipid-phosphatidylcholine mixed emulsion formulated as a highly efficient vehicle that facilitates adenoviral gene transfer.

PubMed

Kim, Soo-Yeon; Lee, Sang-Jin; Kim, Jin-Ki; Choi, Han-Gon; Lim, Soo-Jeong

2017-01-01

Cationic lipid-based nanoparticles enhance viral gene transfer by forming electrostatic complexes with adenoviral vectors. We recently demonstrated the superior complexation capabilities of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) emulsion compared with a liposomal counterpart but the cytotoxicity of DOTAP emulsions remained a challenge. The present study is aimed at formulating an emulsion capable of acting as a highly effective viral gene transfer vehicle with reduced cytotoxicity and to physicochemically characterize the structures of virus-emulsion complexes in comparison with virus-liposome complexes when the only difference between emulsions and liposomes was the presence or absence of inner oil core. The emulsion formulation was performed by 1) reducing the content of DOTAP while increasing the content of zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 2) optimizing the oil content. The complexation capability of formulated DOTAP:DMPC mixed emulsions was similar to those of emulsions containing DOTAP alone while displaying significantly lower cytotoxicity. The complexation capabilities of the DOTAP:DMPC mixed emulsion were serum-compatible and were monitored in a variety of cell types, whereas its liposomal counterpart was totally ineffective. Characterization by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and dynamic light scattering studies indicated that the optimized emulsions spontaneously surrounded the virus particles to generate emulsions that encapsulated the viral particles, whereas viral particles merely attached to the surfaces of the counterpart liposomes to form multiviral aggregates. Overall, these studies demonstrated that optimized DOTAP:DMPC mixed emulsions are potentially useful for adenoviral gene delivery due to less cytotoxicity and the unique ability to encapsulate the viral particle, highlighting the importance of nanoparticle formulation.

Optimization and physicochemical characterization of a cationic lipid-phosphatidylcholine mixed emulsion formulated as a highly efficient vehicle that facilitates adenoviral gene transfer

PubMed Central

Kim, Soo-Yeon; Lee, Sang-Jin; Kim, Jin-Ki; Choi, Han-Gon; Lim, Soo-Jeong

2017-01-01

Cationic lipid-based nanoparticles enhance viral gene transfer by forming electrostatic complexes with adenoviral vectors. We recently demonstrated the superior complexation capabilities of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) emulsion compared with a liposomal counterpart but the cytotoxicity of DOTAP emulsions remained a challenge. The present study is aimed at formulating an emulsion capable of acting as a highly effective viral gene transfer vehicle with reduced cytotoxicity and to physicochemically characterize the structures of virus-emulsion complexes in comparison with virus–liposome complexes when the only difference between emulsions and liposomes was the presence or absence of inner oil core. The emulsion formulation was performed by 1) reducing the content of DOTAP while increasing the content of zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 2) optimizing the oil content. The complexation capability of formulated DOTAP:DMPC mixed emulsions was similar to those of emulsions containing DOTAP alone while displaying significantly lower cytotoxicity. The complexation capabilities of the DOTAP:DMPC mixed emulsion were serum-compatible and were monitored in a variety of cell types, whereas its liposomal counterpart was totally ineffective. Characterization by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and dynamic light scattering studies indicated that the optimized emulsions spontaneously surrounded the virus particles to generate emulsions that encapsulated the viral particles, whereas viral particles merely attached to the surfaces of the counterpart liposomes to form multiviral aggregates. Overall, these studies demonstrated that optimized DOTAP:DMPC mixed emulsions are potentially useful for adenoviral gene delivery due to less cytotoxicity and the unique ability to encapsulate the viral particle, highlighting the importance of nanoparticle formulation. PMID:29070949

Development of serratiopeptidase and metronidazole based alginate microspheres for wound healing.

PubMed

Rath, G; Johal, E S; Goyal, Amit K

2011-02-01

The objective of this study was to establish an effective therapy system for wound management. The present work describes preparation of metronidazole/serratiopeptidase loaded alginate microspheres by emulsification method. In vitro characterizations like particle size analysis, % yield, % encapsulation, and in vitro release were carried out. Wound healing assessment was determined by physical, histological, and biochemical methods. Wound healing performance of experimental formulations was compared with marketed product in rabbits. Result obtained for alginate microspheres showed good loading efficiency with spherical in shape. Experimentation suggests wound healing is improved by using serratiopeptidase and metronidazole in full thickness wounds in rabbits.

Microencapsulation of β-Carotene Based on Casein/Guar Gum Blend Using Zeta Potential-Yield Stress Phenomenon: an Approach to Enhance Photo-stability and Retention of Functionality.

PubMed

Thakur, Deepika; Jain, Ashay; Ghoshal, Gargi; Shivhare, U S; Katare, O P

2017-07-01

β-Carotene, abundant majorly in carrot, pink guava yams, spinach, kale, sweet potato, and palm oil, is an important nutrient for human health due to its scavenging action upon reactive free radicals wherever produced in the body. Inclusion of liposoluble β-carotene in foods and food ingredients is a challenging aspect due to its labile nature and low absorption from natural sources. This fact has led to the application of encapsulation of β-carotene to improve stability and bioavailability. The present work was aimed to fabricate microcapsules (MCs) of β-carotene oily dispersion using the complex coacervation technique with casein (CA) and guar gum (GG) blend. The ratio of CA:GG was found to be 1:0.5 (w/v) when optimized on the basis of zeta potential-yield stress phenomenon. These possessed a higher percentage yield (71.34 ± 0.55%), lower particle size (176.47 ± 4.65 μm), higher encapsulation efficiency (65.95 ± 5.33%), and in general, a uniform surface morphology was observed with particles showing optimized release behavior. Prepared MCs manifested effective and controlled release (up to 98%) following zero-order kinetics which was adequately explained by the Korseymer-Peppas model. The stability of the freeze-dried MCs was established in simulated gastrointestinal fluids (SGF, SIF) for 8 h. Antioxidant activity of the MCs was studied and revealed the retention of the functional architecture of β-carotene in freeze-dried MCs. Minimal photolytic degradation upon encapsulation of β-carotene addressed the challenge regarding photo-stability of β-carotene as confirmed via mass spectroscopy.

Optimizing the taste-masked formulation of acetaminophen using sodium caseinate and lecithin by experimental design.

PubMed

Hoang Thi, Thanh Huong; Lemdani, Mohamed; Flament, Marie-Pierre

2013-09-10

In a previous study of ours, the association of sodium caseinate and lecithin was demonstrated to be promising for masking the bitterness of acetaminophen via drug encapsulation. The encapsulating mechanisms were suggested to be based on the segregation of multicomponent droplets occurring during spray-drying. The spray-dried particles delayed the drug release within the mouth during the early time upon administration and hence masked the bitterness. Indeed, taste-masking is achieved if, within the frame of 1-2 min, drug substance is either not released or the released amount is below the human threshold for identifying its bad taste. The aim of this work was (i) to evaluate the effect of various processing and formulation parameters on the taste-masking efficiency and (ii) to determine the optimal formulation for optimal taste-masking effect. Four investigated input variables included inlet temperature (X1), spray flow (X2), sodium caseinate amount (X3) and lecithin amount (X4). The percentage of drug release amount during the first 2 min was considered as the response variable (Y). A 2(4)-full factorial design was applied and allowed screening for the most influential variables i.e. sodium caseinate amount and lecithin amount. Optimizing these two variables was therefore conducted by a simplex approach. The SEM and DSC results of spray-dried powder prepared under optimal conditions showed that drug seemed to be well encapsulated. The drug release during the first 2 min significantly decreased, 7-fold less than the unmasked drug particles. Therefore, the optimal formulation that performed the best taste-masking effect was successfully achieved. Copyright © 2013 Elsevier B.V. All rights reserved.

Silica encapsulation of fluorescent nanodiamonds for colloidal stability and facile surface functionalization.

PubMed

Bumb, Ambika; Sarkar, Susanta K; Billington, Neil; Brechbiel, Martin W; Neuman, Keir C

2013-05-29

Fluorescent nanodiamonds (FNDs) emit in the near-IR and do not photobleach or photoblink. These properties make FNDs better suited for numerous imaging applications compared with commonly used fluorescence agents such as organic dyes and quantum dots. However, nanodiamonds do not form stable suspensions in aqueous buffer, are prone to aggregation, and are difficult to functionalize. Here we present a method for encapsulating nanodiamonds with silica using an innovative liposome-based encapsulation process that renders the particle surface biocompatible, stable, and readily functionalized through routine linking chemistries. Furthermore, the method selects for a desired particle size and produces a monodisperse agent. We attached biotin to the silica-coated FNDs and tracked the three-dimensional motion of a biotinylated FND tethered by a single DNA molecule with high spatial and temporal resolution.

Development of a Sono-Assembled, Bifunctional Soy Peptide Nanoparticle for Cellular Delivery of Hydrophobic Active Cargoes.

PubMed

Zhang, Yuanhong; Zhao, Mouming; Ning, Zhengxiang; Yu, Shujuan; Tang, Ning; Zhou, Feibai

2018-04-25

Soy proteins are prone to aggregate upon proteolysis, hindering their sustainable development in food processing. Here, a continuous work on the large insoluble peptide aggregates was carried out, aiming to develop a new type of soy peptide-based nanoparticle (SPN) for active cargo delivery. Sono-assembled SPN in spherical appearance and core-shell structure maintained by noncovalent interactions was successfully fabricated, exhibiting small particle size (103.95 nm) in a homogeneous distribution state (PDI = 0.18). Curcumin as a model cargo was efficiently encapsulated into SPN upon sonication, showing high water dispersity (129.6 mg/L, 10 4 higher than its water solubility) and storage stability. Additionally, the pepsin-resistant SPN contributed to the controlled release of curcumin at the intestinal phase and thus significantly improved the bioaccessibility. Encapsulated curcumin was effective in protecting glutamate-induced toxicity in PC12 cells, where the matrix SPN can simultaneously reduce lipid peroxidation and elevate antioxidant enzymes levels, innovatively demonstrating its bifunctionality during cellular delivery.

Spray drying of lipid-based systems loaded with Camellia sinensis polyphenols.

PubMed

Secolin, Vanessa A; Souza, Claudia R F; Oliveira, Wanderley P

2017-03-01

In this work, spray-dried lipid systems based on soy phosphatidylcholine, cholesterol and lauroyl polyoxylglycerides for entrapping Green tea polyphenols were produced. The aim was to study the effects of the encapsulating composition and spray drying conditions on the system performance and physicochemical product properties. The spray dryer powder production yield falls around 50.7 ± 2.8%, which is typical for lab scale spray dryers. Wrinkled and rounded particles, with low surface porosities were generated, independent of the drying carriers (trehalose or lactose) used. The product showed high encapsulation efficiency of Green tea polyphenols, which was promptly redispersible in water. It presented low density, and good compressive and flow properties. The results herein reported confirm the feasibility of the entrapment of Green tea polyphenols in lipid-based compositions by spray drying in presence of the drying carriers evaluated. The spray-dried microparticles show high potential to be used as additive in food, nutraceutical and pharmaceutical products.

Core-shell biopolymer nanoparticle delivery systems: synthesis and characterization of curcumin fortified zein-pectin nanoparticles.

PubMed

Hu, Kun; Huang, Xiaoxia; Gao, Yongqing; Huang, Xulin; Xiao, Hang; McClements, David Julian

2015-09-01

Biopolymer core-shell nanoparticles were fabricated using a hydrophobic protein (zein) as the core and a hydrophilic polysaccharide (pectin) as the shell. Particles were prepared by coating cationic zein nanoparticles with anionic pectin molecules using electrostatic deposition (pH 4). The core-shell nanoparticles were fortified with curcumin (a hydrophobic bioactive molecule) at a high loading efficiency (>86%). The resulting nanoparticles were spherical, relatively small (diameter ≈ 250 nm), and had a narrow size distribution (polydispersity index ≈ 0.24). The encapsulated curcumin was in an amorphous (rather than crystalline form) as detected by differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) and Raman spectra indicated that the encapsulated curcumin interacted with zein mainly through hydrophobic interactions. The nanoparticles were converted into a powdered form that had good water-dispersibility. These core-shell biopolymer nanoparticles could be useful for incorporating curcumin into functional foods and beverages, as well as dietary supplements and pharmaceutical products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Safranal-loaded solid lipid nanoparticles: evaluation of sunscreen and moisturizing potential for topical applications

PubMed Central

Khameneh, Bahman; Halimi, Vahid; Jaafari, Mahmoud Reza; Golmohammadzadeh, Shiva

2015-01-01

Objective(s): In the current study, sunscreen and moisturizing properties of solid lipid nanoparticle (SLN)-safranal formulations were evaluated. Materials and Methods: Series of SLN were prepared using glyceryl monostearate, Tween 80 and different amounts of safranal by high shear homogenization, and ultrasound and high-pressure homogenization (HPH) methods. SLN formulations were characterized for size, zeta potential, morphology, thermal properties, and encapsulation efficacy. The Sun Protection Factor (SPF) of the products was determined in vitro using transpore tape. The moisturizing activity of the products was also evaluated by corneometer. Results: The SPF of SLN-safranal formulations was increased when the amount of safranal increased. Mean particle size for all formulas was approximately 106 nm by probe sonication and 233 nm using HPH method. The encapsulation efficiency of safranal was around 70% for all SLN-safranal formulations. Conclusion: The results conclude that SLN-safranal formulations were found to be effective for topical delivery of safranal and succeeded in providing appropriate sunscreen properties. PMID:25810877

Essential oils: from extraction to encapsulation.

PubMed

El Asbahani, A; Miladi, K; Badri, W; Sala, M; Aït Addi, E H; Casabianca, H; El Mousadik, A; Hartmann, D; Jilale, A; Renaud, F N R; Elaissari, A

2015-04-10

Essential oils are natural products which have many interesting applications. Extraction of essential oils from plants is performed by classical and innovative methods. Numerous encapsulation processes have been developed and reported in the literature in order to encapsulate biomolecules, active molecules, nanocrystals, oils and also essential oils for various applications such as in vitro diagnosis, therapy, cosmetic, textile, food etc. Essential oils encapsulation led to numerous new formulations with new applications. This insures the protection of the fragile oil and controlled release. The most commonly prepared carriers are polymer particles, liposomes and solid lipid nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

Encapsulation of Mo₂C in MoS₂ inorganic fullerene-like nanoparticles and nanotubes.

PubMed

Wiesel, Inna; Popovitz-Biro, Ronit; Tenne, Reshef

2013-02-21

Mo(2)C nanoparticles encapsulated within MoS(2) inorganic fullerene-like nanoparticles and nanotubes were produced by carbothermal reaction at 1200-1300 °C inside a vertical induction furnace. The particles were analyzed using various electron microscopy techniques and complementary methods.

Ternary particles for effective vaccine delivery to the pulmonary system

NASA Astrophysics Data System (ADS)

Terry, Treniece La'shay

Progress in the fields of molecular biology and genomics has provided great insight into the pathogenesis of disease and the defense mechanisms of the immune system. This knowledge has lead to the classification of an array of abnormal genes, for which, treatment relies on cellular expression of proteins. The utility of DNA-based vaccines hold great promise for the treatment of genetically based and infectious diseases, which ranges from hemophilia, cystic fibrosis, and HIV. Synthetic delivery systems consisting of cationic polymers, such as polyethylenimine (PEI), are capable of condensing DNA into compact structures, maximizing cellular uptake of DNA and yielding high levels of protein expression. To date, short term expression is a major obstacle in the development of gene therapies and has halted their expansion in clinical applications. This study intends to develop a sustained release vaccine delivery system using PLA-PEG block copolymers encapsulating PEI:DNA polyplexes. To enhance the effectiveness of such DNA-based vaccines, resident antigen presenting cells, macrophages and dendritic cells, will be targeted within the alveoli regions of the lungs. Porous microspheres will be engineered with aerodynamic properties capable of achieving deep lung deposition. A fabrication technique using concentric nozzles will be developed to produce porous microspheres. It was observed that modifications in the dispersed to continuous phase ratios have the largest influence on particle size distributions, release rates and encapsulation efficiency which ranged form 80--95% with fourteen days of release. Amphiphilic block copolymers were also used to fabricate porous microspheres. The confirmation of PEG within the biodegradable polymer backbone was found to have a tremendous impact on the microsphere morphology and encapsulation efficiency which varied from 50--90%. Porous microspheres were capable of providing sustained gene expression when tested in vitro using the luciferase reporter gene plasmid DNA. Prolonged expression was obtained for 9 days. PLGA and PLA-PEG microspheres were administered in vivo by intra-tracheal instillation and produced an acute inflammatory response, as observed from the large presence of neutrophils. The response using PLA-PEG microspheres yielded a lower total cell count signifying the incorporation of PEG into the copolymer backbone enhances the biocompatibility of the delivery system.

Rational Design of Multifunctional Polymeric Nanoparticles Based on Poly(l-histidine) and d-α-Vitamin E Succinate for Reversing Tumor Multidrug Resistance.

PubMed

Li, Zhen; Chen, Qixian; Qi, Yan; Liu, Zhihao; Hao, Tangna; Sun, Xiaoxin; Qiao, Mingxi; Ma, Xiaodong; Xu, Ting; Zhao, Xiuli; Yang, Chunrong; Chen, Dawei

2018-04-11

A multifunctional nanoparticulate system composed of methoxy poly(ethylene glycol)-poly(l-histidine)-d-α-vitamin E succinate (MPEG-PLH-VES) copolymers for encapsulation of doxorubicin (DOX) was elaborated with the aim of circumventing the multidrug resistance (MDR) in breast cancer treatment. The MPEG-PLH-VES nanoparticles (NPs) were subsequently functionalized with biotin motif for targeted drug delivery. The MPEG-PLH-VES copolymer exerts no obvious effect on the P-gp expression level of MCF-7/ADR but exhibited a significant influence on the loss of mitochondrial membrane potential, the reduction of intracellular ATP level, and the inhibition of P-gp ATPase activity of MCF-7/ADR cells. The constructed MPEG-PLH-VES NPs exhibited an acidic pH-induced increase on particle size in aqueous solution. The DOX-encapsulated MPEG-PLH-VES/biotin-PEG-VES (MPEG-PLH-VES/B) NPs were characterized to possess high drug encapsulation efficiency of approximate 90%, an average particle size of approximately 130 nm, and a pH-responsive drug release profile in acidic milieu. Confocal laser scanning microscopy (CLSM) investigations revealed that the DOX-loaded NPs resulted in an effective delivery of DOX into MCF-/ADR cells and a notable carrier-facilitated escape from endolysosomal entrapment. Pertaining to the in vitro cytotoxicity evaluation, the DOX-loaded MPEG-PLH-VES/B NPs resulted in more pronounced cytotoxicity to MCF-/ADR cells compared with DOX-loaded MPEG-PLH-VES NPs and free DOX solution. In vivo imaging study in MCF-7/ADR tumor-engrafted mice exhibited that the MPEG-PLH-VES/B NPs accumulated at the tumor site more effectively than MPEG-PLH-VES NPs due to the biotin-mediated active targeting effect. In accordance with the in vitro results, DOX-loaded MPEG-PLH-VES/B NPs showed the strongest inhibitory effect against the MCF-7/ADR xenografted tumors with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The multifunctional MPEG-PLH-VES/B nanoparticulate system has been demonstrated to provide a promising strategy for efficient delivery of DOX into MCF-7/ADR cancerous cells and reversing MDR.

Microsponges based novel drug delivery system for augmented arthritis therapy

PubMed Central

Osmani, Riyaz Ali M.; Aloorkar, Nagesh H.; Ingale, Dipti J.; Kulkarni, Parthasarathi K.; Hani, Umme; Bhosale, Rohit R.; Jayachandra Dev, Dandasi

2015-01-01

The motive behind present work was to formulate and evaluate gel containing microsponges of diclofenac diethylamine to provide prolonged release for proficient arthritis therapy. Quasi-emulsion solvent diffusion method was implied using Eudragit RS-100 and microsponges with varied drug–polymer ratios were prepared. For the sake of optimization, diverse factors affecting microparticles physical properties were too investigated. Microsponges were characterized by SEM, DSC, FT-IR, XRPD and particle size analysis, and evaluated for morphology, drug loading, in vitro drug release and ex vivo diffusion as well. There were no chemical interactions between drug and polymers used as revealed by compatibility studies outcomes. The drug polymer ratio reflected notable effect on drug content, encapsulation efficiency and particle size. SEM results revealed spherical microsponges with porous surface, and had 7.21 μm mean particle size. The microsponges were then incorporated in gel; which exhibited viscous modulus along with pseudoplastic behavior. In vitro drug release results depicted that microsponges with 1:2 drug–polymer ratio were more efficient to give extended drug release of 75.88% at the end of 8 h; while conventional formulation get exhausted incredibly earlier by releasing 81.11% drug at the end of 4 h only. Thus the formulated microsponge-based gel of diclofenac diethylamine would be a promising alternative to conventional therapy for safer and efficient treatment of arthritis and musculoskeletal disorders. PMID:26594124

Microsponges based novel drug delivery system for augmented arthritis therapy.

PubMed

Osmani, Riyaz Ali M; Aloorkar, Nagesh H; Ingale, Dipti J; Kulkarni, Parthasarathi K; Hani, Umme; Bhosale, Rohit R; Jayachandra Dev, Dandasi

2015-10-01

The motive behind present work was to formulate and evaluate gel containing microsponges of diclofenac diethylamine to provide prolonged release for proficient arthritis therapy. Quasi-emulsion solvent diffusion method was implied using Eudragit RS-100 and microsponges with varied drug-polymer ratios were prepared. For the sake of optimization, diverse factors affecting microparticles physical properties were too investigated. Microsponges were characterized by SEM, DSC, FT-IR, XRPD and particle size analysis, and evaluated for morphology, drug loading, in vitro drug release and ex vivo diffusion as well. There were no chemical interactions between drug and polymers used as revealed by compatibility studies outcomes. The drug polymer ratio reflected notable effect on drug content, encapsulation efficiency and particle size. SEM results revealed spherical microsponges with porous surface, and had 7.21 μm mean particle size. The microsponges were then incorporated in gel; which exhibited viscous modulus along with pseudoplastic behavior. In vitro drug release results depicted that microsponges with 1:2 drug-polymer ratio were more efficient to give extended drug release of 75.88% at the end of 8 h; while conventional formulation get exhausted incredibly earlier by releasing 81.11% drug at the end of 4 h only. Thus the formulated microsponge-based gel of diclofenac diethylamine would be a promising alternative to conventional therapy for safer and efficient treatment of arthritis and musculoskeletal disorders.

Programmable In Vitro Coencapsidation of Guest Proteins for Intracellular Delivery by Virus-like Particles.

PubMed

Dashti, Noor H; Abidin, Rufika S; Sainsbury, Frank

2018-05-22

Bioinspired self-sorting and self-assembling systems using engineered versions of natural protein cages are being developed for biocatalysis and therapeutic delivery. The packaging and intracellular delivery of guest proteins is of particular interest for both in vitro and in vivo cell engineering. However, there is a lack of bionanotechnology platforms that combine programmable guest protein encapsidation with efficient intracellular uptake. We report a minimal peptide anchor for in vivo self-sorting of cargo-linked capsomeres of murine polyomavirus (MPyV) that enables controlled encapsidation of guest proteins by in vitro self-assembly. Using Förster resonance energy transfer, we demonstrate the flexibility in this system to support coencapsidation of multiple proteins. Complementing these ensemble measurements with single-particle analysis by super-resolution microscopy shows that the stochastic nature of coencapsidation is an overriding principle. This has implications for the design and deployment of both native and engineered self-sorting encapsulation systems and for the assembly of infectious virions. Taking advantage of the encoded affinity for sialic acids ubiquitously displayed on the surface of mammalian cells, we demonstrate the ability of self-assembled MPyV virus-like particles to mediate efficient delivery of guest proteins to the cytosol of primary human cells. This platform for programmable coencapsidation and efficient cytosolic delivery of complementary biomolecules therefore has enormous potential in cell engineering.

Mechanical Properties of Steel Encapsulated Metal Matrix Composites

NASA Astrophysics Data System (ADS)

Fudger, Sean; Klier, Eric; Karandikar, Prashant; McWilliams, Brandon; Ni, Chaoying

This research evaluates a coefficient of thermal expansion (CTE) mismatch induced residual compressive stress approach as a means of improving the ductility of metal matrix composites (MMCs). MMCs are frequently incorporated into advanced material systems due to their tailorable material properties. However, they often have insufficient strength and ductility for many structural applications. By combining MMCs with high strength steels in a hybridized, macro composite materials system that exploits the CTE mismatch, materials systems with improved strength, damage tolerance, and structural efficiency can be obtained. Macro hybridized systems consisting of steel encapsulated light metal MMCs were produced with the goal of creating a system which takes advantage of the high strength, modulus, and damage tolerance of steels and high specific stiffness and low density of MMCs while mitigating the high density of steels and the poor ductility of MMCs. Aluminum and magnesium based particulate reinforced MMCs combine many of the desirable characteristic of metals and ceramics, particularly the unique ability to tailor their CTE. This work aims to compare the performance of macro hybridized material systems consisting of aluminum or magnesium MMCs reinforced with Al2O3, SiC, or B4C particles and encapsulated by A36 steel, 304 stainless steel, or cold worked Nitronic® 50 stainless steels.

Polymeric micelles encapsulating fisetin improve the therapeutic effect in colon cancer.

PubMed

Chen, Yishan; Wu, Qinjie; Song, Linjiang; He, Tao; Li, Yuchen; Li, Ling; Su, Weijun; Liu, Lei; Qian, Zhiyong; Gong, Changyang

2015-01-14

The natural flavonoid fisetin (3,3',4',7-tetrahydroxyflavone) was discovered to possess antitumor activity, revealing its potential value in future chemotherapy. However, its poor water solubility makes it difficult for intravenous administration. In this study, the monomethyl poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) copolymer was applied to prepare nanoassemblies of fisetin by a self-assembly procedure. The prepared fisetin micelles gained a mean particle size of 22 ± 3 nm, polydisperse index of 0.163 ± 0.032, drug loading of 9.88 ± 0.14%, and encapsulation efficiency of 98.53 ± 0.02%. Compared with free fisetin, fisetin micelles demonstrated a sustained and prolonged in vitro release behavior, as well as enhanced cytotoxicity, cellular uptake, and fisetin-induced apoptosis in CT26 cells. As for in vivo studies, fisetin micelles were more competent for suppressing tumor growth and prolonging survival time than free fisetin in the subcutaneous CT26 tumor model. Furthermore, histological analysis, terminal deoxynucleotidyl transferase-mediated nick-end labeling assay, immunohistochemical detection of Ki-67, and microvessel density detection were conducted, demonstrating that fisetin micelles gained increased tumor apoptosis induction, proliferation suppression, and antiangiogenesis activities. In conclusion, we have successfully produced a MPEG-PCL-based nanocarrier encapsulating fisetin with enhanced antitumor activity.

PLGA nanoparticles introduction into mitoxantrone-loaded ultrasound-responsive liposomes: In vitro and in vivo investigations.

PubMed

Xin, Yuxuan; Qi, Qi; Mao, Zhenmin; Zhan, Xiaoping

2017-08-07

A novel ultrasound-responsive liposomal system for tumor targeting was prepared in order to increase the antitumor efficacy and decrease serious side effects. In this paper, PLGA nanoparticles were used ultrasound-responsive agents instead of conventional microbubbles. The PLGA-nanoparticles were prepared by an emulsion solvent evaporation method. The liposomes were prepared by a lipid film hydration method. Particle size, zeta potential, encapsulation efficiency and drug loading capacity of the liposomes were studied by light scattering analysis and dialysis. Transmission electron microscopy (TEM) and atomic force microscope (AFM) were used to investigate the morphology of liposomes. The release in vitro was carried out in the pH 7.4 phosphate buffer solutions, as a result, liposome L3 encapsulating PLGA-nanoparticles displayed good stability under simulative physiological conditions and quickly responsive release under the ultrasound. The release in vivo was carried out on the rats, as a result, liposome L3 showed higher bioavailability than traditional intravenous injectable administration, and liposome L3 showed higher elimination ratio after stimulation by ultrasound than L3 without stimulation. Thus, the novel ultrasound-responsive liposome encapsulating PLGA-nanoparticles has a potential to be developed as a new drug delivery system for anti-tumor drug. Copyright © 2017 Elsevier B.V. All rights reserved.

Chitosan-Coated Cinnamon/Oregano-Loaded Solid Lipid Nanoparticles to Augment 5-Fluorouracil Cytotoxicity for Colorectal Cancer: Extract Standardization, Nanoparticle Optimization, and Cytotoxicity Evaluation.

PubMed

Kamel, Kamel M; Khalil, Islam A; Rateb, Mostafa E; Elgendy, Hosieny; Elhawary, Seham

2017-09-13

This study aimed to coat lipid-based nanocarriers with chitosan to encapsulate nutraceuticals, minimize opsonization, and facilitate passive-targeting. Phase one was concerned with standardization according to the World Health Organization. Qualitative analysis using liquid chromatography-high-resolution mass spectrometry (LC-HRMS/MS) investigated the active constituents, especially reported cytotoxic agents. Cinnamaldehyde and rosmarinic acid were selected to be quantified using high-performance liquid chromatography. Phase two was aimed to encapsulate both extracts in solid lipid nanoparticles (core) and chitosan (shell) to gain the advantages of both materials properties. The developed experimental model suggested an optimum formulation with 2% lipid, 2.3% surfactant, and 0.4% chitosan to achieve a particle size of 254.77 nm, polydispersity index of 0.28, zeta potential of +15.26, and entrapment efficiency percentage of 77.3% and 69.1% for cinnamon and oregano, respectively. Phase three was focused on the evaluation of cytotoxic activity unencapsulated/encapsulated cinnamon and oregano extracts with/without 5-fluorouracil on HCT-116 cells. This study confirmed the success of the suggested combination with 5-fluorouracil for treating human colon carcinoma with a low dose leading to decreasing side effects and allowing uninterrupted therapy.

Synthetic mast-cell granules as adjuvants to promote and polarize immunity in lymph nodes

NASA Astrophysics Data System (ADS)

St. John, Ashley L.; Chan, Cheryl Y.; Staats, Herman F.; Leong, Kam W.; Abraham, Soman N.

2012-03-01

Granules of mast cells (MCs) enhance adaptive immunity when, on activation, they are released as stable particles. Here we show that submicrometre particles modelled after MC granules augment immunity when used as adjuvants in vaccines. The synthetic particles, which consist of a carbohydrate backbone with encapsulated inflammatory mediators such as tumour necrosis factor, replicate attributes of MCs in vivo including the targeting of draining lymph nodes and the timed release of the encapsulated mediators. When used as an adjuvant during vaccination of mice with haemagglutinin from the influenza virus, the particles enhanced adaptive immune responses and increased survival of mice on lethal challenge. Furthermore, differential loading of the particles with the cytokine IL-12 directed the character of the response towards Th1 lymphocytes. The synthetic MC adjuvants replicate and enhance the functions of MCs during vaccination, and can be extended to polarize the resulting immunity.

Enteric-coated capsules filled with mono-disperse micro-particles containing PLGA-lipid-PEG nanoparticles for oral delivery of insulin.

PubMed

Yu, Fei; Li, Yang; Liu, Chang Sheng; Chen, Qin; Wang, Gui Huan; Guo, Wei; Wu, Xue E; Li, Dong Hui; Wu, Winston Duo; Chen, Xiao Dong

2015-04-30

The success of the oral delivery of insulin (INS) as a therapeutic protein drug would significantly improve the quality of life of diabetic patients who would otherwise receive multiple daily INS injections. The oral delivery of INS, however, is still limited in its delivery efficiency, which could be due to the chemical, enzymatic, and adsorption barriers. In this work, in an attempt to improve the delivery efficiency, the INS-loaded polymer-lipid hybrid nanoparticles (INS-PLGA-lipid-PEG NPs) were designed and constructed through a double-emulsion solvent evaporation technique, followed by formulation of the spherical micro-particles using a spray freeze dryer (SFD). This kind of dryers has a uniquely designed microfluidic aerosol nozzle (MFAN), ensuring the formation of uniform particles. The resulted particles of ∼212 μm could easily be reverted to discrete INS-PLGA-lipid-PEG NPs in an aqueous solution. The INS-PLGA-lipid-PEG NPs created in this work showed a highly negative surface charge, excellent entrapment efficiency (92.3%) and a sustained drug release (∼24 h). Confocal laser scanning microscopy and flow cytometer were used to show that the cellular uptake efficiency for the INS-PLGA-lipid-PEG NPs was more effective than the INS in Caco-2 cells. More importantly, the in vivo pharmacodynamics demonstrated that the orally delivered system induced a prolonged decrease in blood glucose levels among diabetic rats. The relative bioavailability of INS compared with subcutaneous injection in diabetic rats was found to be approximately 12%. These results suggested that the encapsulated INS-PLGA-lipid-PEG NPs are promising and should be investigated further in the near future as an effective INS oral delivery system. Copyright © 2015. Published by Elsevier B.V.

A Comparative Cytotoxic Evaluation of Disulfiram Encapsulated PLGA Nanoparticles on MCF-7 Cells

PubMed Central

Fasehee, Hamidreza; Ghavamzadeh, Ardeshir; Alimoghaddam, Kamran; Ghaffari, Seyed-Hamidollah; Faghihi, Shahab

2017-01-01

Background: Disulfiram is oral aldehyde dehydrogenase (ALDH) inhibitor that has been used in the treatment of alcoholism. Recent studies show that this drug has anticancer properties; however, its rapid degradation has limited its clinical application. Encapsulation of disulfiram polymeric nanoparticles (NPs) may improve its anticancer activities and protect rapid degradation of the drug. Materials and Methods: A poly (lactide-co-Glycolide) (PLGA) was developed for encapsulation of disulfiram and its delivery into breast cancer cells. Disulfiram encapsulated PLGA NPs were prepared by nanoprecipitation method and were characterized by Scanning Electron Microscopy (SEM). The loading and encapsulation efficiency of NPs were determined using UV-Visible spectroscopy. Cell cytotoxicity of free and encapsulated form of disulfiram is also determined using MTT assay. Results: Disulfiram encapsulated PLGA NPs had uniform size with 165 nm. Drug loading and entrapment efficiency were 5.35 ±0.03% and 58.85±1.01%. The results of MTT assay showed that disulfiram encapsulated PLGA NPs were more potent in induction of apoptosis compare to free disulfiram. Conclusion: Based on the results obtained in the present study it can be concluded that encapsulation of disulfiram with PLGA can protect its degradation in improve its cytotoxicity on breast cancer cells. PMID:28875004

Encapsulation of Mo2C in MoS2 inorganic fullerene-like nanoparticles and nanotubes

NASA Astrophysics Data System (ADS)

Wiesel, Inna; Popovitz-Biro, Ronit; Tenne, Reshef

2013-01-01

Mo2C nanoparticles encapsulated within MoS2 inorganic fullerene-like nanoparticles and nanotubes were produced by carbothermal reaction at 1200-1300 °C inside a vertical induction furnace. The particles were analyzed using various electron microscopy techniques and complementary methods.

Encapsulation Efficiency and Micellar Structure of Solute-Carrying Block Copolymer Nanoparticles

PubMed Central

Woodhead, Jeffrey L.; Hall, Carol K.

2011-01-01

We use discontinuous molecular dynamics (DMD) computer simulation to investigate the encapsulation efficiency and micellar structure of solute-carrying block copolymer nanoparticles as a function of packing fraction, polymer volume fraction, solute mole fraction, and the interaction parameters between the hydrophobic head blocks and between the head and the solute. The encapsulation efficiency increases with increasing polymer volume fraction and packing fraction but decreases with increasing head-head interaction strength. The latter is due to an increased tendency for the solute to remain on the micelle surface. We compared two different nanoparticle assembly methods, one in which the solute and copolymer co-associate and the other in which the copolymer micelle is formed before the introduction of solute. The assembly method does not affect the encapsulation efficiency but does affect the solute uptake kinetics. Both head-solute interaction strength and head-head interaction strength affect the density profile of the micelles; increases in the former cause the solute to distribute more evenly throughout the micelle, while increases in the latter cause the solute to concentrate further from the center of the micelle. We explain our results in the context of a model of drug insertion into micelles formulated by Kumar and Prud’homme; as conditions become more conducive to micelle formation, a stronger energy barrier to solute insertion forms which in turn decreases the encapsulation efficiency of the system. PMID:21918582

Capsule-Like Safe Genetic Vectors - Cell-Penetrating Core-Shell Particles Selectively Release Functional Small RNA and Entrap its Encoding DNA.

PubMed

Yu, Han; Pan, Houwen Matthew; Evalin, Fnu; Trau, Dieter Wilhelm; Patzel, Volker

2018-06-05

The breakthrough of genetic therapy is set back by the lack of suitable genetic vector systems. We present the development of permeability-tunable, capsule-like, polymeric, micron-sized, core-shell particles for delivery of recombinant nucleic acids into target cells. These particles were demonstrated to effectively release rod-shaped small hairpin RNA and to selectively retain the RNA-encoding DNA template which was designed to form a bulky tripartite structure. Thus, they can serve as delivery vectors preloaded with cargo RNA or alternatively as RNA producing micro-bioreactors. The internalization of particles by human tissue culture cells inversely correlated with particle size and with the cell to particle ratio, though at a higher than stoichiometric excess of particles over cells, cell viability was impaired. Among primary human peripheral blood mononuclear cells, up to 50% of the monocytes displayed positive uptake of particles. Finally, these particles efficiently delivered siRNA into HEK293T cells triggering functional knockdown of the target gene lamin A/C. Particle-mediated knockdown was superior to that observed after conventional siRNA delivery via lipofection. Core-shell particles protect encapsulated nucleic acids from degradation and target cell genomes from direct contact with recombinant DNA, thus representing a promising delivery vector system that can be explored for genetic therapy and vaccination.

Studies on paclitaxel-loaded glyceryl monostearate nanoparticles.

PubMed

Shenoy, Vikram Subraya; Rajyaguru, Tushar Himmatlal; Gude, Rajiv Phondu; Murthy, Rayasa S Ramchandra

2009-09-01

Solid lipid nanoparticles (SLNs) of Paclitaxel were prepared by modified Hot homogenization method using Glyceryl monostearate (GMS). The SLNs were characterized for its physicochemical characteristics such as mean particle size, percentage entrapment efficiency and zeta potential, which were found to be 226 nm, 92.43% and -29.4 mV, respectively. The Transmission Electron Microscopy (TEM) studies showed that prepared SLNs were of spherical shape. The drug retarding efficiency of the lipid (GMS) was better in pH 7.4 compared to pH 3.5. The release profile showed a tendency to follow Higuchi diffusion pattern at pH 7.4 and Peppas-Korsenmeyer model at pH 3.5. Chemosensitivity assay carried out using B16F10 cell lines showed that anti-proliferative activity of Paclitaxel was not hindered due to encapsulation.

One step effective removal of Congo Red in chitosan nanoparticles by encapsulation

NASA Astrophysics Data System (ADS)

Alver, Erol; Bulut, Mehmet; Metin, Ayşegül Ülkü; Çiftçi, Hakan

2017-01-01

Chitosan nanoparticles (CNPs) were prepared with ionotropic gelation between chitosan and tripolyphosphate for the removal of Congo Red. The production of chitosan nanoparticles and the dye removal process was carried out in one-step. The removal efficiency of Congo Red by encapsulation within chitosan from the aqueous solution and its storage stability are examined at different pH values. The influence of some parameters such as the initial dye concentration, pH value of the dye solution, electrolyte concentration, tripolyphosphate concentration, mixing time and speed on the encapsulation is examined. Congo Red removal efficiency and encapsulation capacity of chitosan nanoparticles were determined as above 98% and 5107 mg Congo Red/g chitosan, respectively.

Nanostructured Lipid Carriers Loaded with Baicalin: An Efficient Carrier for Enhanced Antidiabetic Effects

PubMed Central

Shi, Feng; Wei, Zheng; Zhao, Yingying; Xu, Ximing

2016-01-01

Context: Recent studies have demonstrated that baicalin has antihyperglycemic effects by inhibiting lipid peroxidation. Baicalin is low hydrophilic and poorly absorbed after oral administration. Thus, a suitable formulation is highly desired to overcome the disadvantages of baicalin. Objective: The objective of this work was to prepare baicalin-loaded nanostructured lipid carriers (B-NLCs) for enhanced antidiabetic effects. Materials and Methods: B-NLCs were prepared by high-pressure homogenization method using Precirol as the solid lipid and Miglyol as the liquid lipid. The properties of the NLCs, such as particle size, zeta potential (ZP), and drug encapsulation efficiency (EE), were investigated. The morphology of NLCs was observed by transmission electron microscopy. In addition, drug release and antidiabetic activity were also studied. Results: The results revealed that B-NLCs particles were uniformly in the nanosize range and of spherical morphology with a mean size of 92 ± 3.1 nm, a ZP of −31.35 ± 3.08 mV, and an EE of 85.29 ± 3.42%. Baicalin was released from NLCs in a sustained manner. In addition, B-NLCs showed a significantly higher antidiabetic efficacy compared with baicalin. Conclusion: B-NLCs described in this study are well-suited for the delivery of baicalin. SUMMARY Currently, herbal medicines have attracted increasing attention as a complementary approach for type 2 diabetesBaicalin has antihyperglycemic effects by inhibiting lipid peroxidationA suitable formulation is highly desired to overcome the disadvantages (poor solubility and low bioavailability) of baicalinNanostructured lipid carriers could enhance the antidiabetic effects of baicalin. Abbreviations used: B-NLCs: Baicalin-Loaded Nanostructured Lipid Carriers, B-SUS: Baicalin Water Suspension, EE: Encapsulation Efficiency, FBG: Fasting Blood Glucose, HbAlc: Glycosylated Hemoglobin, HPLC: High-performance Liquid Chromatography; NLCs: Nanostructured Lipid Carriers, PI: Polydispersity Index, SD: Sprague-Dawley, SLNs: Solid lipid nanoparticles, STZ: Streptozotocin, TC: Total cholesterol, TEM: Transmission Electron Microscope, TG: Total Triglyceride, ZP: Zeta Potential. PMID:27601850

Nanostructured Lipid Carriers Loaded with Baicalin: An Efficient Carrier for Enhanced Antidiabetic Effects.

PubMed

Shi, Feng; Wei, Zheng; Zhao, Yingying; Xu, Ximing

2016-01-01

Recent studies have demonstrated that baicalin has antihyperglycemic effects by inhibiting lipid peroxidation. Baicalin is low hydrophilic and poorly absorbed after oral administration. Thus, a suitable formulation is highly desired to overcome the disadvantages of baicalin. The objective of this work was to prepare baicalin-loaded nanostructured lipid carriers (B-NLCs) for enhanced antidiabetic effects. B-NLCs were prepared by high-pressure homogenization method using Precirol as the solid lipid and Miglyol as the liquid lipid. The properties of the NLCs, such as particle size, zeta potential (ZP), and drug encapsulation efficiency (EE), were investigated. The morphology of NLCs was observed by transmission electron microscopy. In addition, drug release and antidiabetic activity were also studied. The results revealed that B-NLCs particles were uniformly in the nanosize range and of spherical morphology with a mean size of 92 ± 3.1 nm, a ZP of -31.35 ± 3.08 mV, and an EE of 85.29 ± 3.42%. Baicalin was released from NLCs in a sustained manner. In addition, B-NLCs showed a significantly higher antidiabetic efficacy compared with baicalin. B-NLCs described in this study are well-suited for the delivery of baicalin. Currently, herbal medicines have attracted increasing attention as a complementary approach for type 2 diabetesBaicalin has antihyperglycemic effects by inhibiting lipid peroxidationA suitable formulation is highly desired to overcome the disadvantages (poor solubility and low bioavailability) of baicalinNanostructured lipid carriers could enhance the antidiabetic effects of baicalin. Abbreviations used: B-NLCs: Baicalin-Loaded Nanostructured Lipid Carriers, B-SUS: Baicalin Water Suspension, EE: Encapsulation Efficiency, FBG: Fasting Blood Glucose, HbAlc: Glycosylated Hemoglobin, HPLC: High-performance Liquid Chromatography; NLCs: Nanostructured Lipid Carriers, PI: Polydispersity Index, SD: Sprague-Dawley, SLNs: Solid lipid nanoparticles, STZ: Streptozotocin, TC: Total cholesterol, TEM: Transmission Electron Microscope, TG: Total Triglyceride, ZP: Zeta Potential.

Development of alginate microspheres containing thyme essential oil using ionic gelation.

PubMed

Benavides, Sergio; Cortés, Pablo; Parada, Javier; Franco, Wendy

2016-08-01

Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000rpm/5min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation and physicochemical of microemulsion based on macadamia nut oil

NASA Astrophysics Data System (ADS)

Tu, Xinghao; Chen, Hong; Du, Liqing

2018-03-01

The objective of the present work was to study the preparation, optimization and characteristic of nanostructured lipid carriers(NLCs) based on macadamia nut oil. NLC with various macadamia nut oil content were successfully prepared by an optimized microfluidization method using stearic acid as solid lipid and pluronic F68 as surfactant. As a result, NLC with particle size about 286nm were obtained, and the polydispersity index(PI) of all developed NLC were below 0.2 which indicate a narrow size distribution. Furthermore, the encapsulation efficiency and loading capability were investigated as well. Physical stability of NLC demonstrated that particles of system were stable at room temperature and low temperature. Differential scanning calorimetry(DSC) investigation show that the inner structure and recrystallinity of lipid matrix within NLC were greatly influenced by the content of macadamia nut oil.

Enhanced tumor targeting of cRGD peptide-conjugated albumin nanoparticles in the BxPC-3 cell line.

PubMed

Yu, Xinzhe; Song, Yunlong; Di, Yang; He, Hang; Fu, Deliang; Jin, Chen

2016-08-12

The emerging albumin nanoparticle brings new hope for the delivery of antitumor drugs. However, a lack of robust tumor targeting greatly limits its application. In this paper, cyclic arginine-glycine-aspartic-conjugated, gemcitabine-loaded human serum albumin nanoparticles (cRGD-Gem-HSA-NPs) were successfully prepared, characterized, and tested in vitro in the BxPC-3 cell line. Initially, 4-N-myristoyl-gemcitabine (Gem-C14) was formed by conjugating myristoyl to the 4-amino group of gemcitabine. Then, cRGD-HSA was synthesized using sulfosuccinimidyl-(4-N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC) cross-linkers. Finally, cRGD-Gem-HSA-NPs were formulated based on the nanoparticle albumin-bound (nab) technology. The resulting NPs were characterized for particle size, zeta potential, morphology, encapsulation efficiency, and drug loading efficiency. In vitro cellular uptake and inhibition studies were conducted to compare Gem-HSA-NPs and cRGD-Gem-HSA-NPs in a human pancreatic cancer cell line (BxPC-3). The cRGD-Gem-HSA-NPs exhibited an average particle size of 160 ± 23 nm. The encapsulation rate and drug loading rate were approximately 83 ± 5.6% and 11 ± 4.2%, respectively. In vitro, the cRGD-anchored NPs exhibited a significantly greater affinity for the BxPC-3 cells compared to non-targeted NPs and free drug. The cRGD-Gem-HSA-NPs also showed the strongest inhibitory effect in the BxPC-3 cells among all the analyzed groups. The improved efficacy of cRGD-Gem-HSA-NPs in the BxPC-3 cell line warrants further in vivo investigations.

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics

PubMed Central

Ahmed, Osama AA; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid–liquid phase separation method, according to the Box–Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance. PMID:25670883

Aerobic TCE degradation by encapsulated toluene-oxidizing bacteria, Pseudomonas putida and Bacillus spp.

PubMed

Kim, Seungjin; Bae, Wookeun; Hwang, Jungmin; Park, Jaewoo

2010-01-01

The degradation rates of toluene and trichloroethylene (TCE) by Pseudomonas putida and Bacillus spp. that were encapsulated in polyethylene glycol (PEG) polymers were evaluated in comparison with the results of exposure to suspended cultures. PEG monomers were polymerized together with TCE-degrading microorganisms, such that the cells were encapsulated in and protected by the matrices of the PEG polymers. TCE concentrations were varied from 0.1 to 1.5 mg/L. In the suspended cultures of P. putida, the TCE removal rate decreased as the initial TCE concentration increased, revealing TCE toxicity or a limitation of reducing power, or both. When the cells were encapsulated, an initial lag period of about 10-20 h was observed for toluene degradation. Once acclimated, the encapsulated P. putida cultures were more tolerant to TCE at an experimental range of 0.6-1.0 mg/L and gave higher transfer efficiencies (mass TCE transformed/mass toluene utilized). When the TCE concentration was low (e.g., 0.1 mg/L) the removal of TCE per unit mass of cells (specific removal) was significantly lower, probably due to a diffusion limitation into the PEG pellet. Encapsulated Bacillus spp. were able to degrade TCE cometabolically. The encapsulated Bacillus spp. gave significantly higher values than did P. putida in the specific removal and the transfer efficiency, particularly at relatively high TCE concentration of approximately 1.0±0.5 mg/L. The transfer efficiency by encapsulated Bacillus spp. in this study was 0.27 mgTCE/mgToluene, which was one to two orders of magnitude greater than the reported values.

A synbiotic multiparticulate microcapsule for enhancing inulin intestinal release and Bifidobacterium gastro-intestinal survivability.

PubMed

Fayed, Bahgat; Abood, Amira; El-Sayed, Hoda S; Hashem, Amal M; Mehanna, Nayra S H

2018-08-01

A novel synbiotic multiparticulate microparticle was produced in the current study to expand the synbiotic industrial applications. Initially, the inulin was fabricated into PLGA nanoparticles. After the inulin entrapment efficiency was boosted to reach 92.9 ± 8.4% by adjusting the formulation parameters, the developed particles were characterized by different techniques such as particle size analyzer, TEM, and TLC. The obtained data showed that the particle size was 115.8 ± 82.7 nm, the particles had smooth surface and round shape, and the fabrication procedure did not affect the integrity of the inulin. Later, the inulin loaded nanoparticles together with selected Bifidobacterium species were double coated with gum arabic and alginate. The maximum survivability of the encapsulated Bifidobacterium in the simulated gastric solution reached 88.29% of the initial population, which was significantly higher than the survivability of the free bacteria. Finally, the inulin release from the multiparticulate microparticles was studied and found to be sustained over three days. Copyright © 2018 Elsevier Ltd. All rights reserved.

Silica encapsulation of fluorescent nanodiamonds for colloidal stability and facile surface functionalization

PubMed Central

Bumb, Ambika; Sarkar, Susanta K.; Billington, Neil; Brechbiel, Martin W.; Neuman, Keir C.

2013-01-01

Fluorescent nanodiamonds (FNDs) emit in the near infrared and do not photo-bleach or photoblink. These properties make FNDs better suited for numerous imaging applications in comparison to commonly used fluorescence agents such as organic dyes and quantum dots. However, nanodiamonds do not form stable suspensions in aqueous buffer, are prone to aggregation, and are difficult to functionalize. Here, we present a method to encapsulate nanodiamonds with silica using an innovative liposome-based encapsulation process that renders the particle surface biocompatible, stable, and readily functionalized through routine linking chemistries. Furthermore, the method selects for a desired particle size and produces a monodisperse agent. We attached biotin to the silica-coated FNDs and tracked the three-dimensional motion of a biotinylated FND tethered by a single DNA molecule with high spatial and temporal resolution. PMID:23581827

Phospholipid Bilayers: Stability and Encapsulation of Nanoparticles

NASA Astrophysics Data System (ADS)

Alipour, Elnaz; Halverson, Duncan; McWhirter, Samantha; Walker, Gilbert C.

2017-05-01

Nanoparticles are widely studied for their potential medical uses in diagnostics and therapeutics. The interface between a nanoparticle and its target has been a focus of research, both to guide the nanoparticle and to prevent it from deactivating. Given nature's frequent use of phospholipid vesicles as carriers, much attention has been paid to phospholipids as a vehicle for drug delivery. The physical chemistry of bilayer formation and nanoparticle encapsulation is complex, touching on fundamental properties of hydrophobicity. Understanding the design rules for particle synthesis and encapsulation is an active area of research. The aim of this review is to provide a perspective on what preparative guideposts have been empirically discovered and how these are related to theoretical understanding. In addition, we aim to summarize how modern theory is beginning to help guide the design of functional particles that can effectively cross biological membranes.

Digital microfluidics and delivery of molecular payloads with magnetic porous silicon chaperones.

PubMed

Dorvee, Jason R; Sailor, Michael J; Miskelly, Gordon M

2008-02-14

Digital microfluidics involves the manipulation of molecules and materials in discrete packages. This paper reviews our work using amphiphilic magnetic microparticles constructed from porous silicon. An individual porous particle can be used to carry a nanomole or smaller quantities of a reagent, and assemblies of the particles can encapsulate and transport microliter droplets of liquid containing inorganic, organic, or biological molecules. The tracking and identification of each particle can be accomplished with spectral labels that are encoded into the particles during their synthesis. When used to chaperone liquid droplets, the labels can identify the separate droplets prior to mixing and also the combined droplets after mixing. Magnetic iron oxide nanoparticles encapsulated in the porous matrix allow the manipulation of the particles or whole droplet assemblies with a magnetic field, and they also allow heating of the particle's payload by means of an externally applied RF field. Examples of organic, inorganic, and biomolecular addition reactions, catalytic reactions, and thermolysis reactions are described.

Encapsulation of organic light emitting diodes

NASA Astrophysics Data System (ADS)

Visweswaran, Bhadri

Organic Light Emitting Diodes (OLEDs) are extremely attractive candidates for flexible display and lighting panels due to their high contrast ratio, light weight and flexible nature. However, the materials in an OLED get oxidized by extremely small quantities of atmospheric moisture and oxygen. To obtain a flexible OLED device, a flexible thin-film barrier encapsulation with low permeability for water is necessary. Water permeates through a thin-film barrier by 4 modes: microcracks, contaminant particles, along interfaces, and through the bulk of the material. We have developed a flexible barrier film made by Plasma Enhanced Chemical Vapor Deposition (PECVD) that is devoid of any microcracks. In this work we have systematically reduced the permeation from the other three modes to come up with a barrier film design for an operating lifetime of over 10 years. To provide quantitative feedback during barrier material development, techniques for measuring low diffusion coefficient and solubility of water in a barrier material have been developed. The mechanism of water diffusion in the barrier has been identified. From the measurements, we have created a model for predicting the operating lifetime from accelerated tests when the lifetime is limited by bulk diffusion. To prevent the particle induced water permeation, we have encapsulated artificial particles and have studied their cross section. A three layer thin-film that can coat a particle at thicknesses smaller than the particle diameter is identified. It is demonstrated to protect a bottom emission OLED device that was contaminated with standard sized glass beads. The photoresist and the organic layers below the barrier film causes sideways permeation that can reduce the lifetime set by permeation through the bulk of the barrier. To prevent the sideways permeation, an impermeable inorganic grid made of the same barrier material is designed. The reduction in sideways permeation due to the impermeable inorganic grid is demonstrated in an encapsulated OLED. In this work, we have dealt with three permeation mechanisms and shown solution to each of them. These steps give us reliable flexible encapsulation that has a lifetime of greater than 10 years.

Optimization of gatifloxacin liposomal hydrogel for enhanced transcorneal permeation.

PubMed

Hosny, Khaled Mohamed

2010-03-01

The aim of this study was to prepare and characterize a topically effective prolonged-release ophthalmic gatifloxacin liposomal hydrogel formulation. Reverse-phase evaporation was used for the preparation of liposomes consisting of phosphatidylcholine (PC) and cholesterol (CH). The effect of PC:CH molar ratio on the percentage of drug encapsulated was investigated. The effect of additives, such as stearylamine (SA) or dicetyl phosphate (DP), as positive and negative charge inducers, respectively, was studied. Morphology, mean size, encapsulation efficiency, and in vitro release of gatifloxacin from liposomes were evaluated. For hydrogel preparation, carbopol 940 was applied. In vitro transcorneal permeation through excised albino rabbit cornea was also determined. Optimal encapsulation efficiency was found at the 5:3 PC:CH molar ratio; by increasing CH content above this limit, the encapsulation efficiency decreased. Positively charged liposomes showed superior entrapment efficiency over other liposomes. Hydrogel-containing liposomes with lipid content PC, CH, and SA in a molar ratio of 5:3:1, respectively, showed best release and transcorneal permeation. These results suggest that the encapsulation of gatifloxacin into liposomes prolonged the in vitro release, depending on composition of the vesicles. In addition, the polymer hydrogel used in the preparation ensured steady, prolonged transcorneal permeation. In conclusion, gatifloxacin liposomal hydrogel is a suitable delivery system for the improvement of the ocular bioavailability of gatifloxacin.

Dendrimer-encapsulated nanoparticle-core micelles as a modular strategy for particle-in-a-box-in-a-box nanostructures.

PubMed

Ten Hove, J B; Wang, J; van Leeuwen, F W B; Velders, A H

2017-12-07

The hierarchically controlled synthesis and characterization of self-assembling macromolecules and particles are key to explore and exploit new nanomaterials. Here we present a versatile strategy for constructing particle-in-a-box-in-a-box systems by assembling dendrimer-encapsulated gold nanoparticles (DENs) into dendrimicelles. This is realized by combining positively charged PAMAM dendrimers with a negative-neutral block copolymer. The number of particles per dendrimicelle can be controlled by mixing DENs with empty PAMAM dendrimers. The dendrimicelles are stable in solution for months and provide improved resistance for the nanoparticles against degradation. The dendrimicelle strategy provides a flexible platform with a plethora of options for variation in the type of nanoparticles, dendrimers and block copolymers used, and hence is tunable for applications ranging from nanomedicine to catalysis.

Storage of nuclear materials by encapsulation in fullerenes

DOEpatents

Coppa, Nicholas V.

1994-01-01

A method of encapsulating radioactive materials inside fullerenes for stable long-term storage. Fullerenes provide a safe and efficient means of disposing of nuclear waste which is extremely stable with respect to the environment. After encapsulation, a radioactive ion is essentially chemically isolated from its external environment.

Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1

PubMed Central

Derikvand, Peyman; Etemadifar, Zahra

2014-01-01

Background: Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. Objectives: The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Materials and Methods: Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. Results: The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. Conclusions: The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels. PMID:25147685

Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1.

PubMed

Derikvand, Peyman; Etemadifar, Zahra

2014-03-01

Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels.

Self-aggregation of cationically modified poly(ε-caprolactone)2-co-poly(ethylene glycol) copolymers: Effect of cationic grafting ligand and poly(ε-caprolactone) chain length.

PubMed

Charoongchit, Pimchanok; Suksiriworapong, Jiraphong; Sripha, Kittisak; Mao, Shirui; Sapin-Minet, Anne; Maincent, Philippe; Junyaprasert, Varaporn Buraphacheep

2017-03-01

Cationic copolymers have been attractive to investigate due to their potential to complexation with anionic drugs and expected to use in the pharmaceutical application. In this study, the modified poly(ε-caprolactone) 2 -co-poly(ethylene glycol) copolymers (P(CL) 2 -PEG) were successfully synthesized by click reaction. The amount of small molecular cationic ligand, propargyltrimethyl ammonium iodide, was varied and grafted onto various mole ratios of P(CL) to PEG. The effects of P(CL) chain length and amount of the grafting cationic ligand on physicochemical properties of polymers and particles were studied. The number-average molecular weights of the copolymers grafted with cationic ligand were found ranging between 10,000 and 23,000g/mol as investigated by NMR. From DSC study, the results showed that the grafting ligand affected thermal behaviors of the copolymers by increasing the glass transition temperature and decreasing the melting temperature of the copolymers. Furthermore, these cationic copolymers could self-aggregate with their critical aggregation concentration depending on mole ratios of hydrophilic to hydrophobic portions. The particles containing higher amounts of the cationic ligand tended to aggregate in both acidic and basic pH environment and at high salt concentration. Additionally, particle size, size distribution (PdI), and morphology of self-assembling particles varied depending on P(CL) chain length and the amount of the grafting cationic ligand. The synthesized cationic copolymer showed a capability to encapsulate a high negatively charged drug, enoxaparin, with an encapsulation efficiency of 87%. After drug incorporation, the particles substantially changed in size, shape, PdI, and zeta potential to become more suitable for drug delivery. These cationic copolymers with flexible properties will be the candidate for further development as carriers for the delivery of negatively charged drugs. Copyright © 2016. Published by Elsevier B.V.

Novel genipin crosslinked atorvastatin loaded sericin nanoparticles for their enhanced antihyperlipidemic activity.

PubMed

Kanoujia, Jovita; Singh, Mahendra; Singh, Pooja; Saraf, Shubhini A

2016-12-01

The objective of this study was to demonstrate the therapeutic as well as biopolymer like characteristics of naturally occurring sericin protein for development of nanoparticulate system of atorvastatin (Atr) to improve therapeutic effect and to reduce toxicity. The sericin encapsulated atorvastatin nanoparticles (Seri-Atr NPs) were prepared by desolvation method utilizing genipin (Gn) as a natural and nontoxic crosslinker. The optimized NPs exhibited small particle size (166±0.30nm), high entrapment efficiency (91±0.69%) and uniform spherical shape with sustained release profile. Moreover, the results of pharmacokinetic studies indicated an increase in AUC0-∞ of NPs (1189.74±52.3hng/ml) compared with Atr (501.84±66hng/ml). The cellular uptake of NPs suggested an interaction of negatively charged particles with the cell surface and considerable reduction in systemic toxicity. Histopathology studies also demonstrated the therapeutic potential of sericin and cytocompatibility. Hence, genipin crosslinked sericin based nanoparticles represents a promising nanoplatform for improved therapeutic efficiency of Atr. Copyright © 2016 Elsevier B.V. All rights reserved.

Engineering M13 for phage display.

PubMed

Sidhu, S S

2001-09-01

Phage display is achieved by fusing polypeptide libraries to phage coat proteins. The resulting phage particles display the polypeptides on their surfaces and they also contain the encoding DNA. Library members with particular functions can be isolated with simple selections and polypeptide sequences can be decoded from the encapsulated DNA. The technology's success depends on the efficiency with which polypeptides can be displayed on the phage surface, and significant progress has been made in engineering M13 bacteriophage coat proteins as improved phage display platforms. Functional display has been achieved with all five M13 coat proteins, with both N- and C-terminal fusions. Also, coat protein mutants have been designed and selected to improve the efficiency of heterologous protein display, and in the extreme case, completely artificial coat proteins have been evolved specifically as display platforms. These studies demonstrate that the M13 phage coat is extremely malleable, and this property can be used to engineer the phage particle specifically for phage display. These improvements expand the utility of phage display as a powerful tool in modern biotechnology.

Single-Particle Tracking of Human Immunodeficiency Virus Type 1 Productive Entry into Human Primary Macrophages.

PubMed

Li, Qin; Li, Wei; Yin, Wen; Guo, Jia; Zhang, Zhi-Ping; Zeng, Dejun; Zhang, Xiaowei; Wu, Yuntao; Zhang, Xian-En; Cui, Zongqiang

2017-04-25

Macrophages are one of the major targets of human immunodeficiency virus (HIV-1), but the viral entry pathway remains poorly understood in these cells. Noninvasive virus labeling and single-virus tracking are effective tools for studying virus entry. Here, we constructed a quantum dot (QD)-encapsulated infectious HIV-1 particle to track viral entry at a single-particle level in live human primary macrophages. QDs were encapsulated in HIV-1 virions by incorporating viral accessory protein Vpr-conjugated QDs during virus assembly. With the HIV-1 particles encapsulating QDs, we monitored the early phase of viral infection in real time and observed that, during infection, HIV-1 was endocytosed in a clathrin-mediated manner; the particles were translocated into Rab5A-positive endosomes, and the core was released into the cytoplasm by viral envelope-mediated endosomal fusion. Drug inhibition assays verified that endosome fusion contributes to HIV-1 productive infection in primary macrophages. Additionally, we observed that a dynamic actin cytoskeleton is critical for HIV-1 entry and intracellular migration in primary macrophages. HIV-1 dynamics and infection could be blocked by multiple different actin inhibitors. Our study revealed a productive entry pathway in macrophages that requires both endosomal function and actin dynamics, which may assist in the development of inhibitors to block the HIV entry in macrophages.

Novel pH responsive polymethacrylic acid-chitosan-polyethylene glycol nanoparticles for oral peptide delivery.

PubMed

Sajeesh, S; Sharma, Chandra P

2006-02-01

In present study, novel pH sensitive polymethacrylic acid-chitosan-polyethylene glycol (PCP) nanoparticles were prepared under mild aqueous conditions via polyelectrolyte complexation. Free radical polymerization of methacrylic acid (MAA) was carried out in presence of chitosan (CS) and polyethylene glycol (PEG) using a water-soluble initiator and particles were obtained spontaneously during polymerization without using organic solvents or surfactants/steric stabilizers. Dried particles were analyzed by scanning electron microscopy (SEM) and particles dispersed in phosphate buffer (pH 7.0) were visualized under transmission electron microscope (TEM). SEM studies indicated that PCP particles have an aggregated and irregular morphology, however, TEM revealed that these aggregated particles were composed of smaller fragments with size less than 1 micron. Insulin and bovine serum albumin (BSA) as model proteins were incorporated into the nanoparticles by diffusion filling method and their in vitro release characteristics were evaluated at pH 1.2 and 7.4. PCP nanoparticles exhibited good protein encapsulation efficiency and pH responsive release profile was observed under in vitro conditions. Trypsin inhibitory effect of these PCP nanoparticles was studied using casein substrate and these particles displayed lesser inhibitory effect than reference polymer carbopol. Preliminary investigation suggests that these particles can serve as good candidate for oral peptide delivery. Copyright 2005 Wiley Periodicals, Inc.

Enhanced optical-to-THz conversion efficiency of photoconductive antenna using dielectric nano-layer encapsulation

NASA Astrophysics Data System (ADS)

Gupta, Abhishek; Rana, Goutam; Bhattacharya, Arkabrata; Singh, Abhishek; Jain, Ravikumar; Bapat, Rudheer D.; Duttagupta, S. P.; Prabhu, S. S.

2018-05-01

Photoconductive antennas (PCAs) are among the most conventional devices used for emission as well as detection of terahertz (THz) radiation. However, due to their low optical-to-THz conversion efficiencies, applications of these devices in out-of-laboratory conditions are limited. In this paper, we report several factors of enhancement in THz emission efficiency from conventional PCAs by coating a nano-layer of dielectric (TiO2) on the active area between the electrodes of a semi-insulating GaAs-based device. Extensive experiments were done to show the effect of thicknesses of the TiO2 layer on the THz power enhancement with different applied optical power and bias voltages. Multiphysics simulations were performed to elucidate the underlying physics behind the enhancement of efficiency of the PCA. Additionally, this layer increases the robustness of the electrode gaps of the PCAs with high electrical insulation as well as protect it from external dust particles.

Study of silicone-based materials for the packaging of optoelectronic devices

NASA Astrophysics Data System (ADS)

Lin, Yeong-Her

The first part of this work is to evaluate the main materials used for the packaging of high power light-emitting diodes (LEDs), i.e., the die attach materials, the encapsulant materials, and high color rendering index(CRI) sol-gel composite materials. All of these materials had been discussed the performance, reliability, and issues in high power LED packages. High power white LEDs are created either from blue or near-ultraviolet chips encapsulated with a yellow phosphor, or from red-green-blue LED light mixing systems. The phosphor excited by blue LED chip was mostly used in experiment of this dissertation. The die attach materials contains filler particles possessing a maximum particle size less than 1.5 mum in diameter blended with epoxy polymer matrix. Such compositions enable thin bond line thickness, which decreases thermal resistance that exists between thermal interface materials and the corresponding mating surfaces. The thermal conductivity of nano silver die attach materials is relatively low, the thermal resistance from the junction to board is just 1.6 KW-1 in the bond line thickness of 5.3 mum, which is much lower than the thermal resistance using conventional die attach materials. The silicone die attach adhesive made in the lab cures through the free radical reaction of epoxy-functional organopolysiloxane and through the hydrosilylation reaction between alkenyl-functional organopolysiloxane and silicone-boned hydrogen-functional organopolysiloxane. By the combination of the free radical reaction and the hydrosilylation reaction, the low-molecular-weight silicone oil will not be out-migrated and not contaminate wire bondability to the LED chip and lead frame. Hence, the silicone die attach adhesive made in the lab can pass all reliability tests, such as operating life test JEDEC 85°C/85RH and room temperature operating life test. For LED encapsulating materials, most of commercial silicone encapsulants still suffer thermal/radiation induced degradations, and thus cause reliability issues and shorten the lifetime. A new high performance silicone has been developed and its performance has been compared with other commercial silicone products in the packaging of high power white LEDs. The high performance silicone also has better results than commercial high refractive index silicone and optical grade epoxy under JEDEC reliability standard for moisture sensitivity test. In synthesis of red dye-doped particles by sol-gel method, it is a novel method to get high color rendering index (CRI) LEDs. These red dye-doped particles, with average diameter of 5 mum, can be mixed with liquid encapsulants to form a uniform distribution in polymer matrix. The red dye-doped particles can be excited by phosphor-emitted yellow light instead of blue light from LED chip. Therefore, warm white LEDs with high CRI can be gotten at high lumen efficiency. The second part of this work is silicone elastomer for biomedical applications, especially in making urological implantable devices. A cross-linked, heat curable, addition-reaction silicone material is prepared. The material may be molded or formed into one or more medical devices. One such medical device could be a catheter used in urological applications. The material is a long term indwelling material that resists encrustation like a metal stent, but is more comfortable because it is silicone-based. The material can be made relatively cheaply compared to metal stents. Furthermore, the material is biocompatible with bladder epithelial cells.

Magnetic separation of encapsulated islet cells labeled with superparamagnetic iron oxide nano particles.

PubMed

Mettler, Esther; Trenkler, Anja; Feilen, Peter J; Wiegand, Frederik; Fottner, Christian; Ehrhart, Friederike; Zimmermann, Heiko; Hwang, Yong Hwa; Lee, Dong Yun; Fischer, Stefan; Schreiber, Laura M; Weber, Matthias M

2013-01-01

Islet cell transplantation is a promising option for the restoration of normal glucose homeostasis in patients with type 1 diabetes. Because graft volume is a crucial issue in islet transplantations for patients with diabetes, we evaluated a new method for increasing functional tissue yield in xenogeneic grafts of encapsulated islets. Islets were labeled with three different superparamagnetic iron oxide nano particles (SPIONs; dextran-coated SPION, siloxane-coated SPION, and heparin-coated SPION). Magnetic separation was performed to separate encapsulated islets from the empty capsules, and cell viability and function were tested. Islets labeled with 1000 μg Fe/ml dextran-coated SPIONs experienced a 69.9% reduction in graft volume, with a 33.2% loss of islet-containing capsules. Islets labeled with 100 μg Fe/ml heparin-coated SPIONs showed a 46.4% reduction in graft volume, with a 4.5% loss of capsules containing islets. No purification could be achieved using siloxane-coated SPIONs due to its toxicity to the primary islets. SPION labeling of islets is useful for transplant purification during islet separation as well as in vivo imaging after transplantation. Furthermore, purification of encapsulated islets can also reduce the volume of the encapsulated islets without impairing their function by removing empty capsules. © 2013 John Wiley & Sons A/S.

Micro-Encapsulated Porphyrins and Phthalocyanines - New Formulations in Photodynamic Therapy

NASA Astrophysics Data System (ADS)

Ion, R. M.

2017-06-01

Photodynamic therapy (PDT), as an innovative method for cancer tretament is based on a concerted action of some drugs, called sensitizers, which generate reactive oxygen species via a photochemical mechanism, leading to cellular necrosis or apoptosis. The present work aims at loading some sensitizers, as porphyrins (P) and phthalocyanines (Pc) into alginate particles. Particles were prepared by dropping alginate into an aqueous solution containing P or Pc and CaCl2, which allows the formation of particles through ionic crosslinking. It was obtained P or Pc loaded alginate beads with an average diameter of about 100 μm. For these systems, this paper analyses the spectroscopic properties, encapsulation into microcapsules, controlled releasing action and their photosensitizer capacity (singlet oxygen generation).

Scalable fabrication of size-controlled chitosan nanoparticles for oral delivery of insulin.

PubMed

He, Zhiyu; Santos, Jose Luis; Tian, Houkuan; Huang, Huahua; Hu, Yizong; Liu, Lixin; Leong, Kam W; Chen, Yongming; Mao, Hai-Quan

2017-06-01

Controlled delivery of protein would find diverse therapeutic applications. Formulation of protein nanoparticles by polyelectrolyte complexation between the protein and a natural polymer such as chitosan (CS) is a popular approach. However, the current method of batch-mode mixing faces significant challenges in scaling up while maintaining size control, high uniformity, and high encapsulation efficiency. Here we report a new method, termed flash nanocomplexation (FNC), to fabricate insulin nanoparticles by infusing aqueous solutions of CS, tripolyphosphate (TPP), and insulin under rapid mixing condition (Re > 1600) in a multi-inlet vortex mixer. In comparison with the bulk-mixing method, the optimized FNC process produces CS/TPP/insulin nanoparticles with a smaller size (down to 45 nm) and narrower size distribution, higher encapsulation efficiency (up to 90%), and pH-dependent nanoparticle dissolution and insulin release. The CS/TPP/insulin nanoparticles can be lyophilized and reconstituted without loss of activity, and produced at a throughput of 5.1 g h -1 when a flow rate of 50 mL min -1 is used. Evaluated in a Type I diabetes rat model, the smaller nanoparticles (45 nm and 115 nm) control the blood glucose level through oral administration more effectively than the larger particles (240 nm). This efficient, reproducible and continuous FNC technique is amenable to scale-up in order to address the critical barrier of manufacturing for the translation of protein nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antibacterial Loaded Spray Dried Chitosan Polyelectrolyte Complexes as Dry Powder Aerosol for the Treatment of Lung Infections

PubMed Central

Mishra, Brahmeshwar; Mishra, Madhusmita; Yadav, Sarita Kumari

2017-01-01

Inhalation delivery of aerosolized antibacterials is preferred over conventional methods of delivery for targeting lung infection. The present study is concerned with the development and characterization of a novel, spray dried, aerosolized, chitosan polyelectrolyte complex (PEC) based microparticles containing antibacterials for the treatment of lung infections. Chitosan polyelectrolyte complex microparticles were formulated by spray drying process. Prepared spray dried chitosan PEC microparticles were studied for surface morphology, drug encapsulation efficiency, moisture content, Carr’s index, solid state interaction by XRD, aerosolization behaviour and in-vitro drug release. In-vitro cytotoxicity studies of microparticles were carried out on H1299 alveolar cell lines. Antibacterial efficacy of microparticles was assessed on the basis of determination of pharmacokinetic parameters in bronchial alveolar lavage (BAL) of rats using PK/PD analysis. The PEC microparticles were mostly spherical and exhibited high drug encapsulation efficiency. Release profiles showed an initial burst phase followed by a secondary sustained release phase. Good aerosolization behaviour as dry powder inhaler was demonstrated by microparticles with high values of recovered dose, emitted dose, and fine particle fraction. No overt cytotoxicity of microparticles was detected against H1299 alveolar cell line. More than 8 to 9 folds higher Cmax values were obtained in BAL fluid with microparticles as compared to intravenously administered antibacterial solution. The findings of the study suggest that chitosan polyelectrolyte complex based microparticles as dry powder inhaler can be an efficient antibacterial delivery system for sustained and effective management of lung infection. PMID:28496463

Production of nanoparticle drug delivery systems with microfluidics tools.

PubMed

Khan, Ikram Ullah; Serra, Christophe A; Anton, Nicolas; Vandamme, Thierry F

2015-04-01

Nowadays the development of composite nano- and microparticles is an extensively studied area of research. This interest is growing because of the potential use of such particles in drug delivery systems. Indeed they can be used in various medical disciplines depending upon their sizes and their size distribution, which determine their final biomedical applications. Amongst the different techniques to produce nanoparticles, microfluidic techniques allow preparing particles having a specific size, a narrow size distribution and high encapsulation efficiency with ease. This review covers the general description of microfluidics, its techniques, advantages and disadvantages with focus on the encapsulation of active principles in polymeric nanoparticles as well as on pure drug nanoparticles. Polymeric nanoparticles constitute the majority of the examples reported; however lipid nanoparticulate systems (DNA, SiRNA nanocarriers) are very comparable and their formulation processes are in most cases exactly similar. Accordingly this review focuses also on active ingredient nanoparticles formulated by nanoprecipitation processes in microfluidic devices in general. It also provides detailed description of the different geometries of most common microfluidic devices and the crucial parameters involved in techniques designed to obtain the desired properties. Although the classical fabrication of nanoparticles drug delivery systems in batch is extremely well-described and developed, their production with microfluidic tools arises today as an emerging field with much more potential. In this review we present and discuss these new possibilities for biomedical applications through the current emerging developments.

The in vitro kinetics of the interactions between PEG-ylated magnetic-fluid-loaded liposomes and macrophages.

PubMed

Martina, Marie-Sophie; Nicolas, Valerie; Wilhelm, Claire; Ménager, Christine; Barratt, Gillian; Lesieur, Sylviane

2007-10-01

Binding and uptake kinetics of magnetic-fluid-loaded liposomes (MFL) by endocytotic cells were investigated in vitro on the model cell-line J774. MFL consisted of unilamellar phosphatidylcholine vesicles (mean hydrodynamic diameter close to 200nm) encapsulating 8-nm nanocrystals of maghemite (gamma-Fe(2)O(3)) and sterically stabilized by introducing 5mol% of distearylphosphatidylcholine poly(ethylene glycol)(2,000) (DSPE-PEG(2,000)) in the vesicle bilayer. The association processes with living macrophages were followed at two levels. On one hand, the lipid vesicles were imaged by confocal fluorescence microscopy. For this purpose 1mol% of rhodamine-marked phosphatidylethanolamine was added to the liposome composition. On the other hand, the iron oxide particles associated with cells were independently quantified by magnetophoresis. All the experiments were similarly performed with PEG-ylated or conventional MFL to point out the role of polymer coating. The results showed cell association with both types of liposomes resulting from binding followed by endocytosis. Steric stabilization by PEG chains reduced binding efficiency limiting the amount of MFL internalized by the macrophages. In contrast, PEG coating did not change the kinetics of endocytosis which exhibited the same first-order rate constant for both conventional and PEG-ylated liposomes. Moreover, lipids and iron oxide particle uptakes were perfectly correlated, indicating that MFL vesicle structure and encapsulation rate were preserved upon cell penetration.

Improvement of citral antimicrobial activity by incorporation into nanostructured lipid carriers: a potential application in food stuffs as a natural preservative.

PubMed

Mokarizadeh, Manijeh; Kafil, Hossein Samadi; Ghanbarzadeh, Saeed; Alizadeh, Ainaz; Hamishehkar, Hamed

2017-10-01

At the present time, utilization of essential oils in food preservation to prevent bacterial and fungal growth and improve shelf life and safety of the food products has notably gained increased interest. The aim of the present study was to improve the antimicrobial efficacy of citral as a natural preservative using nanostructured lipid carriers (NLCs). Formulations of NLCs were characterized using particle size analysis and scanning electron microscopy methods. Possible citral-carrier interaction and citral encapsulation efficiency percent (EE%) were assessed by Fourier transform infrared (FTIR) spectroscopy and gas chromatography techniques, respectively. Antimicrobial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of citral-loaded NLCs were evaluated and compared with the conventional citral emulsion against various gram-positive bacteria ( Staphylococcus aureus , Bacillus cereus ), gram-negative bacteria ( Escherichia coli ), and fungi ( Candida albicans ). Citral-loaded NLCs were spherically shaped nanosized (74.8 nm) particles with narrow size distribution, high EE% (99.84%), and appropriate physical stability during 90 days of storage period. FTIR spectra indicated the interaction between citral and formulation ingredients, which justified the obtained high EE% value. The MIC and MBC values of citral-loaded NLCs were lower than those of citral emulsion for all microorganisms. NLCs formulation showed remarkable capability of encapsulating essential oil and increasing antimicrobial properties to offer effective preservation in food industry.

Synthesis and evaluation of PEG-O-chitosan nanoparticles for delivery of poor water soluble drugs: ibuprofen.

PubMed

Hassani Najafabadi, Alireza; Abdouss, Majid; Faghihi, Shahab

2014-08-01

Current methods for preparation of PEGylated chitosan have limitations such as harsh de protecting step and several purification cycles. In the present study, a facile new method for conjugating methoxy polyethylene glycol (mPEG) to chitosan under mild condition is introduced to improve water solubility of chitosan and control the release of poor water soluble drugs. The method consists of chitosan modification by grafting the C6 position of chitosan to mPEG which is confirmed by Fourier transformed-infrared (FT-IR) and proton nuclear magnetic resonance ((1)HNMR) analyses. The amine groups at the C2 position of chitosan are protected using sodium dodecylsulfate (SDS) which is removed by dialyzing the precipitation against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and (1)HNMR. The synthesized polymer is then employed to prepare nanoparticles which are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) for their size and morphology. The nanoparticles are used for encapsulation of ibuprofen followed by in vitro release investigation in gastrointestinal and simulated biological fluids. The chitosan nanoparticles are used as control. The PEGylated nanoparticles show a particle size of 80 nm with spherical morphology. The results clearly show that drug release from PEGylated chitosan nanoparticles is remarkably slower than chitosan. In addition, drug encapsulation and encapsulation efficiency in PEGylated nanoparticles are dependent on the amount of drug added to the formulation being significantly higher than chitosan nanoparticles. This study provides an efficient, novel, and facile method for preparing a nano carrier system for delivery of water insoluble drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of different desolvating agents on BSA nanoparticle properties and encapsulation of curcumin

NASA Astrophysics Data System (ADS)

Sadeghi, R.; Moosavi-Movahedi, A. A.; Emam-jomeh, Z.; Kalbasi, A.; Razavi, S. H.; Karimi, M.; Kokini, J.

2014-09-01

The desolvation method was successfully used to prepare nanoparticles from bovine serum albumin (BSA) using ethanol, acetone, and their mixtures (70:30 and 50:50, respectively). Ethanol and mixtures of ethanol and acetone led to the most spherical nanoparticles, while using pure acetone resulted in a mixture of spherical and rod shape nanoparticle. Acetone was the solvent with higher encapsulation efficiency equal to 99.2 ± 0.36 %. The polydispersity values of BSA NPs in this study were 0.045 ± 0.007, 0.065 ± 0.013, 0.091 ± 0.012, and 0.120 ± 0.016 for ethanol (100) 4×, Et:Ac (70:30) 4×, Et:Ac (50:50) 4×, and acetone (100) 3×, respectively. Encapsulation efficiencies of curcumin inside BSA NPs were 19.4 ± 2.2 and 19.8 ± 1.6 % for 1.0 and 1.5 molar ratios of curcumin to BSA, respectively. Crosslinking using glutaraldehyde improved the stability of BSA NPs and curcumin-loaded BSA NPs and both groups of nanoparticles were stable for 1 month; the lyophilized curcumin-loaded BSA NPs were able to redisperse in water. The particle size and polydispersity index of redispersed NPs were higher than the original NPs before lyophilization. The size distribution study shows that after 10 s of sonication most nanoparticles were well dispersed; however, a small but significant fraction formed aggregates. Sonication for 10 s decreased the effective diameter and polydispersity of the redispersed nanoparticles, while increasing the sonication time to 20 s did not show significant changes. In vitro release study of curcumin from BSA NPs showed that these biocompatible nanoparticles have the ability to be used as a carrier to improve controlled release of curcumin.

Modified extrusion-spheronization as a technique of microencapsulation for stabilization of choline bitartrate using hydrogenated soya bean oil

PubMed Central

Gangurde, Avinash Bhaskar; Sav, Ajay Kumar; Javeer, Sharadchandra Dagadu; Moravkar, Kailas K; Pawar, Jaywant N; Amin, Purnima D

2015-01-01

Introduction: Choline bitartrate (CBT) is a vital nutrient for fetal brain development and memory function. It is hygroscopic in nature which is associated with stability related problem during storage such as development of fishy odor and discoloration. Aim: Microencapsulation method was adopted to resolve the stability problem and for this hydrogenated soya bean oil (HSO) was used as encapsulating agent. Materials and Methods: Industrially feasible modified extrusion-spheronization technique was selected for microencapsulation. HSO was used as encapsulating agent, hydroxypropyl methyl cellulose E5/E15 as binder and microcrystalline cellulose as spheronization aid. Formulated pellets were evaluated for parameters such as flow property, morphological characteristics, hardness-friability index (HFI), drug content, encapsulation efficiency, and in vitro drug release. The optimized formulations were also characterized for particle size (by laser diffractometry), differential scanning calorimetry, powder X-ray diffractometry (PXRD), Fourier transform infrared spectroscopy, and scanning electron microscopy. Results and Discussions: The results from the study showed that coating of 90% and 60% CBT was successful with respect to all desired evaluation parameters. Optimized formulation was kept for 6 months stability study as per ICH guidelines, and there was no change in color, moisture content, drug content, and no fishy odor was observed. Conclusion: Microencapsulated pellets of CBT using HSO as encapsulating agent were developed using modified extrusion spheronization technique. Optimized formulations, CBT 90% (F5), and CBT 60% (F10), were found to be stable for 4M and 6M, respectively, at accelerated conditions. PMID:26682198

A combined interfacial and in-situ polymerization strategy to construct well-defined core-shell epoxy-containing SiO2-based microcapsules with high encapsulation loading, super thermal stability and nonpolar solvent tolerance

NASA Astrophysics Data System (ADS)

Jia; Wang; Tian; Li; Xu; Jiao; Cao; Wu

2016-10-01

SiO2-based microcapsules containing hydrophobic molecules exhibited potential applications such as extrinsic self-healing, drug delivery, due to outstanding thermal and chemical stability of SiO2. However, to construct SiO2-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue, limiting their further utilization. We herein design a single-batch route, a combined interfacial and in-situ polymerization strategy, to fabricate epoxy-containing SiO2-based microcapsules with both high encapsulation loading and long-term structural stability. The final SiO2-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step. In the subsequent in-situ polymerization step, the initial SiO2-based microcapsules as seeds could efficiently harvest SiO2 precursors and primary SiO2 particles to finely tune the SiO2 wall thickness, thereby enhancing long-term structural stability of the final SiO2-based microcapsules including high thermal stability with almost no any weight loss until 250°C, and strong tolerance against nonpolar solvents such as CCl4 with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days. These SiO2-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.

Effect of particle size of TiO2 and additive materials to improve dye sensitized solar cells efficiency

NASA Astrophysics Data System (ADS)

Ali, Falah H.; Alwan, Dheyaa B.

2018-05-01

It became a great interest Dye-sensitized solar cells (DSSC) as a successful alternative to silicon solar cells in terms of cost and simplicity. These cells rely on a semi-conductive material of electricity TiO2 nanocrystalline which encapsulates glass electrodes from the connected side at a temperature 450°C. In this work, the effect of nanoparticle size shows the size of atoms. The smaller the size of the atoms, the greater the surface area and thus the sufficient absorption of the dye and the stimulation of electrons, where increasing surface area increases efficiency. Then a limited amount was added and at a certain concentration, which led to a reasonable improvement in efficiency. According to this procedure commercially available TiO2 (10 nm,25 nm,33 nm, 50 nm) standard. A TiO2 paste was prepared by mixing commercial TiO2, ethanol, distilled water, F:SnO2 (FTO film thickness 14 μm) conductive glasses. By using Dr. Blade method we got films with appropriate thicknesses, then by using several particle sizes (10 nm, 25 nm, 33 nm, 50 nm),many efficiencies were founded (2.39 %, 2.1 %,1.85 %,1.65%) respectively. Improved solar cell efficiency after addition of several chemical materials and the best that got is Cu (NO3)2. Efficiency became for (10 nm) (2.61 %, 2.34 %,2.1%,1.85%) respectively under 40 mW/cm2.

Encapsulation performance of layer-by-layer microcapsules for proteins.

PubMed

De Temmerman, Marie-Luce; Demeester, Jo; De Vos, Filip; De Smedt, Stefaan C

2011-04-11

This study reports on the encapsulation efficiency of proteins in dextran sulfate/poly-L-arginine-based microcapsules, fabricated via layer-by-layer assembly (LbL). For this purpose, radiolabeled proteins are entrapped in CaCO(3) microparticles, followed by LbL coating of the CaCO(3) cores and subsequent dissolving of the CaCO(3) using EDTA. To allow to improve protein encapsulation in LbL microcapsules, we studied all steps in the preparation of the microcapsules where loss of protein load might occur. The encapsulation efficiency of proteins in LbL microcapsules turns out to be strongly dependent on both the charge and molecular weight of the protein as well as on the number of polyelectrolyte bilayers the microcapsules consist of.

Improving oxidative stability of echium oil emulsions fabricated by Microfluidics: Effect of ionic gelation and phenolic compounds.

PubMed

Comunian, Talita A; Ravanfar, Raheleh; de Castro, Inar Alves; Dando, Robin; Favaro-Trindade, Carmen S; Abbaspourrad, Alireza

2017-10-15

Echium oil is rich in omega-3 fatty acids, which are important because of their benefits to human health; it is, however, unstable. The objective of this work was the coencapsulation of echium oil and quercetin or sinapic acid by microfluidic and ionic gelation techniques. The treatments were analyzed utilizing optical and scanning electron microscopy, encapsulation yield, particle size, thermogravimetry, Fourier transform infrared spectroscopy, stability under stress conditions, and oil oxidative/phenolic compound stability for 30days at 40°C. High encapsulation yield values were obtained (91-97% and 77-90% for the phenolic compounds and oil) and the encapsulated oil was almost seven times more stable than the non-encapsulated oil (0.34 vs 2.42mgMDA/kg oil for encapsulated and non-encapsulated oil, respectively). Encapsulation was shown to promote oxidative stability, allowing new vehicles for the application of these compounds in food without the use of solvents and high temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

Encapsulation and delivery of food ingredients using starch based systems.

PubMed

Zhu, Fan

2017-08-15

Functional ingredients can be encapsulated by various wall materials for controlled release in food and digestion systems. Starch, as one of the most abundant natural carbohydrate polymers, is non-allergenic, GRAS, and cheap. There has been increasing interest of using starch in native and modified forms to encapsulate food ingredients such as flavours, lipids, polyphenols, carotenoids, vitamins, enzymes, and probiotics. Starches from various botanical sources in granular or amorphous forms are modified by chemical, physical, and/or enzymatic means to obtain the desired properties for targeted encapsulation. Other wall materials are also employed in combination with starch to facilitate some types of encapsulation. Various methods of crafting the starch-based encapsulation such as electrospinning, spray drying, antisolvent, amylose inclusion complexation, and nano-emulsification are introduced in this mini-review. The physicochemical and structural properties of the particles are described. The encapsulation systems can positively influence the controlled release of food ingredients in food and nutritional applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

High Resolution NMR Studies of Encapsulated Proteins In Liquid Ethane

PubMed Central

Peterson, Ronald W.; Lefebvre, Brian G.; Wand, A. Joshua

2005-01-01

Many of the difficulties presented by large, aggregation-prone, and membrane proteins to modern solution NMR spectroscopy can be alleviated by actively seeking to increase the effective rate of molecular reorientation. An emerging approach involves encapsulating the protein of interest within the protective shell of a reverse micelle, and dissolving the resulting particle in a low viscosity fluid, such as the short chain alkanes. Here we present the encapsulation of proteins with high structural fidelity within reverse micelles dissolved in liquid ethane. The addition of appropriate co-surfactants can significantly reduce the pressure required for successful encapsulation. At these reduced pressures, the viscosity of the ethane solution is low enough to provide sufficiently rapid molecular reorientation to significantly lengthen the spin-spin NMR relaxation times of the encapsulated protein. PMID:16028922

Purification of complex samples: Implementation of a modular and reconfigurable droplet-based microfluidic platform with cascaded deterministic lateral displacement separation modules

PubMed Central

Pudda, Catherine; Boizot, François; Verplanck, Nicolas; Revol-Cavalier, Frédéric; Berthier, Jean; Thuaire, Aurélie

2018-01-01

Particle separation in microfluidic devices is a common problematic for sample preparation in biology. Deterministic lateral displacement (DLD) is efficiently implemented as a size-based fractionation technique to separate two populations of particles around a specific size. However, real biological samples contain components of many different sizes and a single DLD separation step is not sufficient to purify these complex samples. When connecting several DLD modules in series, pressure balancing at the DLD outlets of each step becomes critical to ensure an optimal separation efficiency. A generic microfluidic platform is presented in this paper to optimize pressure balancing, when DLD separation is connected either to another DLD module or to a different microfluidic function. This is made possible by generating droplets at T-junctions connected to the DLD outlets. Droplets act as pressure controllers, which perform at the same time the encapsulation of DLD sorted particles and the balance of output pressures. The optimized pressures to apply on DLD modules and on T-junctions are determined by a general model that ensures the equilibrium of the entire platform. The proposed separation platform is completely modular and reconfigurable since the same predictive model applies to any cascaded DLD modules of the droplet-based cartridge. PMID:29768490

Fabrication of magnetic and fluorescent chitin and dibutyrylchitin sub-micron particles by oil-in-water emulsification.

PubMed

Blanco-Fernandez, Barbara; Chakravarty, Shatadru; Nkansah, Michael K; Shapiro, Erik M

2016-11-01

Chitin is a carbohydrate polymer with unique pharmacological and immunological properties, however, because of its unwieldy chemistry, the synthesis of discreet sized sub-micron particles has not been well reported. This work describes a facile and flexible method to fabricate biocompatible chitin and dibutyrylchitin sub-micron particles. This technique is based on an oil-in-water emulsification/evaporation method and involves the hydrophobization of chitin by the addition of labile butyryl groups onto chitin, disrupting intermolecular hydrogen bonds and enabling solubility in the organic solvent used as the oil phase during fabrication. The subsequent removal of butyryl groups post-fabrication through alkaline saponification regenerates native chitin while keeping particles morphology intact. Examples of encapsulation of hydrophobic dyes and nanocrystals are demonstrated, specifically using iron oxide nanocrystals and coumarin 6. The prepared particles had diameters between 300-400nm for dibutyrylchitin and 500-600nm for chitin and were highly cytocompatible. Moreover, they were able to encapsulate high amounts of iron oxide nanocrystals and were able to label mammalian cells. We describe a technique to prepare sub-micron particles of highly acetylated chitin (>90%) and dibutyrylchitin and demonstrate their utility as carriers for imaging. Chitin is a polysaccharide capable of stimulating the immune system, a property that depends on the acetamide groups, but its insolubility limits its use. No method for sub-micron particle preparation with highly acetylated chitins have been published. The only approach for the preparation of sub-micron particles uses low acetylation chitins. Dibutyrylchitin, a soluble chitin derivative, was used to prepare particles by oil in water emulsification. Butyryl groups were then removed, forming chitin particles. These particles could be suitable for encapsulation of hydrophobic payloads for drug delivery and cell imaging, as well as, adjuvants for vaccines. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

In silico modelling of drug–polymer interactions for pharmaceutical formulations

PubMed Central

Ahmad, Samina; Johnston, Blair F.; Mackay, Simon P.; Schatzlein, Andreas G.; Gellert, Paul; Sengupta, Durba; Uchegbu, Ijeoma F.

2010-01-01

Selecting polymers for drug encapsulation in pharmaceutical formulations is usually made after extensive trial and error experiments. To speed up excipient choice procedures, we have explored coarse-grained computer simulations (dissipative particle dynamics (DPD) and coarse-grained molecular dynamics using the MARTINI force field) of polymer–drug interactions to study the encapsulation of prednisolone (log p = 1.6), paracetamol (log p = 0.3) and isoniazid (log p = −1.1) in poly(l-lactic acid) (PLA) controlled release microspheres, as well as the encapsulation of propofol (log p = 4.1) in bioavailability enhancing quaternary ammonium palmitoyl glycol chitosan (GCPQ) micelles. Simulations have been compared with experimental data. DPD simulations, in good correlation with experimental data, correctly revealed that hydrophobic drugs (prednisolone and paracetamol) could be encapsulated within PLA microspheres and predicted the experimentally observed paracetamol encapsulation levels (5–8% of the initial drug level) in 50 mg ml−1 PLA microspheres, but only when initial paracetamol levels exceeded 5 mg ml−1. However, the mesoscale technique was unable to model the hydrophilic drug (isoniazid) encapsulation (4–9% of the initial drug level) which was observed in experiments. Molecular dynamics simulations using the MARTINI force field indicated that the self-assembly of GCPQ is rapid, with propofol residing at the interface between micellar hydrophobic and hydrophilic groups, and that there is a heterogeneous distribution of propofol within the GCPQ micelle population. GCPQ–propofol experiments also revealed a population of relatively empty and drug-filled GCPQ particles. PMID:20519214

Enhancement of anti-inflammatory activity of bromelain by its encapsulation in katira gum nanoparticles.

PubMed

Bernela, Manju; Ahuja, Munish; Thakur, Rajesh

2016-06-05

Bromelain-loaded katira gum nanoparticles were synthesized using 3 level optimization process and desirability approach. Nanoparticles of the optimized batch were characterized using particle size analysis, zeta potential, transmission electron microscopy and Fourier-transform infrared spectroscopy. Investigation of their in vivo anti-inflammatory activity by employing carrageenan induced rat-paw oedema method showed that encapsulation of bromelain in katira gum nanoparticles substantially enhanced its anti-inflammatory potential. This may be attributed to enhanced absorption owing to reduced particle size or to protection of bromelain from acid proteases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reducing stress on cells with apoferritin-encapsulated platinum nanoparticles.

PubMed

Zhang, Lianbing; Laug, Linda; Münchgesang, Wolfram; Pippel, Eckhard; Gösele, Ulrich; Brandsch, Matthias; Knez, Mato

2010-01-01

The great potential for medical applications of inorganic nanoparticles in living organisms is severely restricted by the concern that nanoparticles can harmfully interact with biological systems, such as lipid membranes or cell proteins. To enable an uptake of such nanoparticles by cells without harming their membranes, platinum nanoparticles were synthesized within cavities of hollow protein nanospheres (apoferritin). In vitro, the protein-platinum nanoparticles show good catalytic efficiency and long-term stability. Subsequently the particles were tested after ferritin-receptor-mediated incorporation in human intestinal Caco-2 cells. Upon externally induced stress, for example, with hydrogen peroxide, the oxygen species in the cells decreased and the viability of the cells increased.

Synthesis and Applications of Multimodal Hybrid Albumin Nanoparticles for Chemotherapeutic Drug Delivery and Photothermal Therapy Platforms

NASA Astrophysics Data System (ADS)

Peralta, Donna V.

Progress has been made in using human serum albumin nanoparticles (HSAPs) as carrier systems for targeted treatment of cancer. Human serum albumin (HSA), the most abundant human blood protein, can form HSAPs via a desolvation and crosslinking method, with the size of the HSAPs having crucial importance for drug loading and in vivo performance. Gold nanoparticles have also gained medicinal attention due to their ability to absorb near-infrared (NIR) light. These relatively non-toxic particles offer combinational therapy via imaging and photothermal therapy (PPTT) capabilities. A desolvation and crosslinking approach was employed to encapsulate gold nanoparticles (AuNPs), hollow gold nanoshells (AuNSs), and gold nanorods (AuNRs), into efficiently sized HSAPs for future tumor heat ablation via PPTT. The AuNR-HSAPs, AuNP-HSAPs and AuNS-HSAPs had average particle diameters of 222 +/- 5, 195 +/- 9 and 156 +/- 15, respectively. We simultaneously encapsulated AuNRs and the anticancer drug paclitaxel (PAC), forming PAC-AuNR-HSAPs with overall average particle size of 299 +/- 6 nm. Loading of paclitaxel into PAC-AuNR-HSAPs reached 3microg PAC/mg HSA. PAC-AuNR-HSAPs experienced photothermal heating of 46 °C after 15 minutes of NIR laser exposure; the temperature necessary to cause severe cellular hyperthermia. There was a burst release of paclitaxel up to 188 ng caused by the irradiation session, followed by a temporal drug release. AuNR-HSAPs were tested for ablation of renal cell carcinoma using NIR irradiation in vitro. Particles created with the same amount of AuNRs, but varying HSA (1, 5 or 20 mg) showed overall particle size diameters 409 +/- 224, 294 +/- 83 and 167 +/- 4 nm, respectively. Increasing HSAPs causes more toxicity under non-irradiated treatment conditions: AuNR-HSAPs with 20 mg versus 5 mg HSA caused cell viability of 64.5% versus 87%, respectively. All AuNR-HSAPs batches experienced photothermal heating above 42 °C. Coumarin-6, was used to visualize the cellular uptake of AuNR-HSAPs via fluorescence microscopy. Finally, camptothecin (CPT) an antineoplastic agent and BACPT (7-butyl-10-aminocamptothecin) were loaded into HSAPs to combat their aqueous insolubility. BACPT-HSAPs loaded up to 5.25 micrograms BACPT/ mg of HSA. CPT encapsulation could not be determined. BACPT-HSAPs and CPT-HSAPs showed cytotoxicity to human sarcoma cells in vitro. Key words: Hybrid Nanoparticles, Photothermal Therapy, Gold Nanomaterials, Drug Delivery, Combinational Cancer Therapies, Materials, Human Serum Albumin, Colloidal Carriers.

Encapsulation of Alpha-1 antitrypsin in PLGA nanoparticles: In Vitro characterization as an effective aerosol formulation in pulmonary diseases

PubMed Central

2012-01-01

Background Alpha 1- antitrypsin (α1AT) belongs to the superfamily of serpins and inhibits different proteases. α1AT protects the lung from cellular inflammatory enzymes. In the absence of α1AT, the degradation of lung tissue results to pulmonary complications. The pulmonary route is a potent noninvasive route for systemic and local delivery. The aerosolized α1AT not only affects locally its main site of action but also avoids remaining in circulation for a long period of time in peripheral blood. Poly (D, L lactide-co glycolide) (PLGA) is a biodegradable and biocompatible polymer approved for sustained controlled release of peptides and proteins. The aim of this work was to prepare a wide range of particle size as a carrier of protein-loaded nanoparticles to deposit in different parts of the respiratory system especially in the deep lung. Various lactide to glycolide ratio of the copolymer was used to obtain different release profile of the drug which covers extended and rapid drug release in one formulation. Results Nonaqueous and double emulsion techniques were applied for the synthesis of nanoparticles. Nanoparticles were characterized in terms of surface morphology, size distribution, powder X-ray diffraction (XRD), encapsulation efficiency, in vitro drug release, FTIR spectroscopy and differential scanning calorimetry (DSC). To evaluate the nanoparticles cytotoxicity, cell cytotoxicity test was carried out on the Cor L105 human epithelial lung cancer cell line. Nanoparticles were spherical with an average size in the range of 100 nm to 1μ. The encapsulation efficiency was found to be higher when the double emulsion technique was applied. XRD and DSC results indicated that α1AT encapsulated in the nanoparticles existed in an amorphous or disordered-crystalline status in the polymer matrix. The lactic acid to glycolic acid ratio affects the release profile of α1AT. Hence, PLGA with a 50:50 ratios exhibited the ability to release %60 of the drug within 8, but the polymer with a ratio of 75:25 had a continuous and longer release profile. Cytotoxicity studies showed that nanoparticles do not affect cell growth and were not toxic to cells. Conclusion In summary, α1AT-loaded nanoparticles may be considered as a novel formulation for efficient treatment of many pulmonary diseases. PMID:22607686

Biopolymer-prebiotic carbohydrate blends and their effects on the retention of bioactive compounds and maintenance of antioxidant activity.

PubMed

Silva, Eric Keven; Zabot, Giovani L; Cazarin, Cinthia B B; Maróstica, Mário R; Meireles, M Angela A

2016-06-25

The objective of this study was to evaluate the use of inulin (IN), a prebiotic carbohydrate without superficial activity, as an encapsulating matrix of lipophilic bioactive compounds. For achieving the encapsulation, IN was associated with biopolymers that present superficial activity: modified starch (HiCap), whey protein isolate (WPI) and gum acacia (GA). Encapsulation was performed through emulsification assisted by ultrasound followed by freeze-drying (FD) process to dry the emulsions. All blends retained geranylgeraniol. GA-IN blend yielded the highest geranylgeraniol retention (96±2wt.%) and entrapment efficiency (94±3wt.%), whilst WPI-IN blend yielded the highest encapsulation efficiency (88±2wt.%). After encapsulation, composition of geranylgeraniol in the annatto seed oil was maintained (23.0±0.5g/100g of oil). Such findings indicate that the method of encapsulation preserved the active compound. All blends were also effective for maintaining the antioxidant activity of the oil through ORAC and DPPH analyses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of encapsulation of a synthetic long peptide in PLGA nanoparticles: low-burst release is crucial for efficient CD8(+) T cell activation.

PubMed

Silva, A L; Rosalia, R A; Sazak, A; Carstens, M G; Ossendorp, F; Oostendorp, J; Jiskoot, W

2013-04-01

Overlapping synthetic long peptides (SLPs) hold great promise for immunotherapy of cancer. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are being developed as delivery systems to improve the potency of peptide-based therapeutic cancer vaccines. Our aim was to optimize PLGA NP for SLP delivery with respect to encapsulation and release, using OVA24, a 24-residue long synthetic antigenic peptide covering a CTL epitope of ovalbumin (SIINFEKL), as a model antigen. Peptide-loaded PLGA NPs were prepared by a double emulsion/solvent evaporation technique. Using standard conditions (acidic inner aqueous phase), we observed that either encapsulation was very low (1-30%), or burst release extremely high (>70%) upon resuspension of NP in physiological buffers. By adjusting formulation and process parameters, we uncovered that the pH of the first emulsion was critical to efficient encapsulation and controlled release. In particular, an alkaline inner aqueous phase resulted in circa 330 nm sized NP with approximately 40% encapsulation efficiency and low (<10%) burst release. These NP showed enhanced MHC class I restricted T cell activation in vitro when compared to high-burst releasing NP and soluble OVA24, proving that efficient entrapment of the antigen is crucial to induce a potent cellular immune response. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method.

PubMed

Kalani, Mahshid; Yunus, Robiah

2012-01-01

The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks.

Use of lectin-functionalized particles for oral immunotherapy

PubMed Central

Diesner, Susanne C; Wang, Xue-Yan; Jensen-Jarolim, Erika; Untersmayr, Eva; Gabor, Franz

2013-01-01

Immunotherapy, in recent times, has found its application in a variety of immunologically mediated diseases. Oral immunotherapy may not only increase patient compliance but may, in particular, also induce both systemic as well as mucosal immune responses, due to mucosal application of active agents. To improve the bioavailability and to trigger strong immunological responses, recent research projects focused on the encapsulation of drugs and antigens into polymer particles. These particles protect the loaded antigen from the harsh conditions in the GI tract. Furthermore, modification of the surface of particles by the use of lectins, such as Aleuria aurantia lectin, wheatgerm agglutinin or Ulex europaeus-I, enhances the binding to epithelial cells, in particular to membranous cells, of the mucosa-associated lymphoid tissue. Membranous cell-specific targeting leads to an improved transepithelial transport of the particle carriers. Thus, enhanced uptake and presentation of the encapsulated antigen by antigen-presenting cells favor strong systemic, but also local, mucosal immune responses. PMID:22834202

Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method

PubMed Central

Kalani, Mahshid; Yunus, Robiah

2012-01-01

The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks. PMID:22619552

Palladium-tin catalysts for the direct synthesis of H 2O 2 with high selectivity

DOE PAGES

Freakley, Simon J.; He, Qian; Harrhy, Jonathan H.; ...

2016-02-25

The direct synthesis of hydrogen peroxide (H 2O 2 ) from H 2 and O 2 represents a potentially atom-efficient alternative to the current industrial indirect process. We show that the addition of tin to palladium catalysts coupled with an appropriate heat treatment cycle switches off the sequential hydrogenation and decomposition reactions, enabling selectivities of >95% toward H 2O 2 . This effect arises from a tin oxide surface layer that encapsulates small Pd-rich particles while leaving larger Pd-Sn alloy particles exposed. In conclusion, we show that this effect is a general feature for oxide-supported Pd catalysts containing an appropriatemore » second metal oxide component, and we set out the design principles for producing high-selectivity Pd-based catalysts for direct H 2O 2 production that do not contain gold.« less

A polyhedron made of tRNAs.

PubMed

Severcan, Isil; Geary, Cody; Chworos, Arkadiusz; Voss, Neil; Jacovetty, Erica; Jaeger, Luc

2010-09-01

Supramolecular assembly is a powerful strategy used by nature to build nanoscale architectures with predefined sizes and shapes. With synthetic systems, however, numerous challenges remain to be solved before precise control over the synthesis, folding and assembly of rationally designed three-dimensional nano-objects made of RNA can be achieved. Here, using the transfer RNA molecule as a structural building block, we report the design, efficient synthesis and structural characterization of stable, modular three-dimensional particles adopting the polyhedral geometry of a non-uniform square antiprism. The spatial control within the final architecture allows the precise positioning and encapsulation of proteins. This work demonstrates that a remarkable degree of structural control can be achieved with RNA structural motifs for the construction of thermostable three-dimensional nano-architectures that do not rely on helix bundles or tensegrity. RNA three-dimensional particles could potentially be used as carriers or scaffolds in nanomedicine and synthetic biology.

A polyhedron made of tRNAs

PubMed Central

Severcan, Isil; Geary, Cody; Chworos, Arkadiusz; Voss, Neil; Jacovetty, Erica; Jaeger, Luc

2010-01-01

Supra-molecular assembly is a powerful strategy used by nature for building nano-scale architectures with predefined sizes and shapes. Numerous challenges remain however to be solved in order to demonstrate precise control over the synthesis, folding and assembly of rationally designed three-dimensional (3D) nano-objects made of RNA. Using the transfer RNA molecule as a structural building block, we report the design, efficient synthesis and structural characterization of stable, modular 3D particles adopting the polyhedral geometry of a non-uniform square antiprism. The spatial control within the final architecture allows precise positioning and encapsulation of proteins. This work demonstrates that a remarkable degree of structural control can be achieved with RNA structural motifs to build thermostable 3D nano-architectures that do not rely on helix bundles or tensegrity. RNA 3D particles can potentially be used as carriers or scaffolds in nano-medicine and synthetic biology. PMID:20729899

Enhanced bioavailability of orally administered flurbiprofen by combined use of hydroxypropyl-cyclodextrin and poly(alkyl-cyanoacrylate) nanoparticles.

PubMed

Zhao, Xiaoyun; Li, Wei; Luo, Qiuhua; Zhang, Xiangrong

2014-03-01

Flurbiprofen was formulated into nanoparticle suspension to improve its oral bioavailability. Hydroxypropyl-β-cyclodextrin inclusion-flurbiprofen complex (HP-β-CD-FP) was prepared, then incorporating this complex into poly(alkyl-cyanoacrylate) (PACA) nanoparticles. HP-β-CD-FP-PACA nanoparticle was prepared by the emulsion solvent polymerization method. The zeta potential was -26.8 mV, the mean volume particle diameter was 134 nm, drug encapsulation efficiency was 53.3 ± 3.6 % and concentration was 1.5 mg/mL. The bioavailability of flurbiprofen from optimized nanoparticles was assessed in male Wistar rats at a dose of 15 mg/kg. As compared to the flurbiprofen suspension, 211.6 % relative bioavailability was observed for flurbiprofen nanoparticles. The reduced particle size and increased surface area may contribute to improve oral bioavailability of flurbiprofen.

A poly(ethylene glycol)-based surfactant for formulation of drug-loaded mucus penetrating particles

PubMed Central

Mert, Olcay; Lai, Samuel K.; Ensign, Laura; Yang, Ming; Wang, Ying-Ying; Wood, Joseph; Hanes, Justin

2011-01-01

Mucosal surfaces are protected by a highly viscoelastic and adhesive mucus layer that traps most foreign particles, including conventional drug and gene carriers. Trapped particles are eliminated on the order of seconds to hours by mucus clearance mechanisms, precluding sustained and targeted drug and nucleic acid delivery to mucosal tissues. We have previously shown that polymeric coatings that minimize adhesive interactions with mucus constituents lead to particles that rapidly penetrate human mucus secretions. Nevertheless, a particular challenge in formulating drug-loaded mucus penetrating particles (MPP) is that many commonly used surfactants are either mucoadhesive, or do not facilitate efficient drug encapsulation. We tested a novel surfactant molecule for particle formulation composed of Vitamin E conjugated to 5 kDa polyethylene glycol (VP5k). We show that VP5k-coated poly(lactide-co-glycolide) (PLGA) nanoparticles rapidly penetrate human cervicovaginal mucus, whereas PLGA nanoparticles coated with polyvinyl alcohol or Vitamin E conjugated to 1 kDa PEG were trapped. Importantly, VP5k facilitated high loading of paclitaxel, a frontline chemo drug, into PLGA MPP, with controlled release for at least 4 days and negligible burst release. Our results offer a promising new method for engineering biodegradable, drug-loaded MPP for sustained and targeted delivery of therapeutics at mucosal surfaces. PMID:21911015

The therapeutic effect of nano-encapsulated and nano-emulsion forms of carvacrol on experimental liver fibrosis.

PubMed

Hussein, Jihan; El-Banna, Mona; Mahmoud, Khaled F; Morsy, Safaa; Abdel Latif, Yasmin; Medhat, Dalia; Refaat, Eman; Farrag, Abdel Razik; El-Daly, Sherien M

2017-06-01

The present study aimed to compare the therapeutic efficiency of nano-encapsulated and nano-emulsion carvacrol administration on liver injury in thioacetamide (TAA) treated rats. To fulfill our target, we used sixty male albino rats classified into six groups as follow: control, nano-encapsulated carvacrol, nano-emulsion carvacrol, thioacetamide, treated nano-encapsulated carvacrol and treated nano-emulsion carvacrol groups. Blood samples were collected from all groups and the separated serum was used for analysis of the following biochemical parameters; aspartate aminotransferase (AST), alanine aminotransferase (ALT), S100 B protein, alpha fetoprotein (AFP) and caspase-3. The levels of malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), monocyte chemoattractant protein-1(MCP-1) and hydroxyproline content were all evaluated in liver tissue homogenate. Histopathological examinations for liver tissues were also performed. Thioacetamide induced hepatic damage in rats as revealed by the significant increase in the levels of serum ALT, AST and produced oxidative stress as displayed by the significant elevation in the levels of hepatic MDA and NO concomitant with a significant decrease in GSH. In addition, thioacetamide significantly increased serum S100B protein, alpha fetoprotein and caspase-3 along with hepatic MCP-1 and hydroxyproline; these results were confirmed by the histopathological investigation. In contrast, nano-encapsulated and nano-emulsion carvacrol were able to ameliorate these negative changes in the thioacetamide injected rats. However, the effect of the nano-encapsulated form of carvacrol was more prominent than the nano-emulsion form. Nano-encapsulated and nano-emulsion carvacrol can ameliorate thioacetamide induced liver injury. These results could be attributed to the potential anti-inflammatory, antioxidant, and anti-apoptotic activities of carvacrol in addition to the effectiveness of the encapsulation technique that can protect carvacrol structure and increase its efficiency and stability. Moreover, nano-encapsulation of carvacrol is more efficient than nano-emulsion. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Budesonide Loaded PLGA Nanoparticles for Targeting the Inflamed Intestinal Mucosa--Pharmaceutical Characterization and Fluorescence Imaging.

PubMed

Ali, Hussain; Weigmann, Benno; Collnot, Eva-Maria; Khan, Saeed Ahmad; Windbergs, Maike; Lehr, Claus-Michael

2016-05-01

The purpose of this study was to evaluate the specifically targeted efficiency of budesonide loaded PLGA nanoparticles for the treatment of inflammatory bowel disease (IBD). The nanoparticles were prepared by an oil/water (O/W) emulsion evaporation technique. The nanoparticles were characterized for their size, shape and in vitro drug release profile. Solid state characterization was carried out by differential scanning calorimetry (DSC) and X-ray Power diffraction (XPRD). In order to evaluate the targeted efficiency of nanoparticles, a particle localization study in the healthy and in the inflamed colon was determined in vivo. These data were complemented by cryo-sections. Nanoparticles were 200 ± 05 nm in size with a smooth and spherical shape. The encapsulation efficiency was around 85 ± 3.5%, which was find-out by both, direct and indirect methods. Release of budesonide from the nanoparticles showed a biphasic release profile with an initial burst followed by sustained release. XPRD data revealed that the drug in the polymer matrix existed in crystalline state. Nanoparticles accumulation in inflamed tissues was evaluated by in-vivo imaging system and it was found that particles are accumulated in abundance at the site of inflammation when compared to the healthy group. The study demonstrates that the budesonide loaded PLGA nanoparticles are an efficient delivery system for targeted drug delivery to the inflamed intestinal mucosa.

Co-encapsulation of CdSe/ZnS and CeO2 nanoparticles in waterborne polymer dispersions: enhancement of fluorescence emission under sunlight.

PubMed

De San Luis, Alicia; Paulis, Maria; Leiza, Jose Ramon

2017-11-15

Hybrid core/shell polymer particles with co-encapsulated quantum dots (QDs) (CdSe/ZnS) and CeO 2 nanoparticles have been synthesized in a two stage semi-batch emulsion polymerization process. In the first stage, both inorganic nanoparticles are incorporated into cross-linked polystyrene (PS) particles by miniemulsion polymerization. This hybrid dispersion is then used as the seed to produce the core/shell particles by starved feeding of methyl methacrylate and divinylbenzene (MMA/DVB) monomers. The core/shell hybrid dispersions maintained in the dark exhibit stable fluorescence emission over time, and notably their fluorescence intensity increases under sunlight, likely due to the effect of the co-encapsulated CeO 2 nanoparticles that change the optical properties of the environment of the quantum dot particles. The fluorescence increase depends on the QD : CeO 2 ratio, with the 1 : 2 ratio resulting in the highest increase (280%). Furthermore, a film forming hybrid latex has been synthesized using the former core/shell PS/QD/CeO 2 /PMMA particles as seeds and feeding under semi-batch conditions methyl methacrylate, butyl acrylate and acrylic acid. Films cast from this core/shell/shell hybrid dispersion also exhibit fluorescence, and as for the core/shell latex the fluorescence increases under sunlight exposure. Interestingly, the increase in the film is at least two times higher than that in the latex, which is attributed to the additional effect of the neighboring coalesced particles containing CeO 2 affecting the environment of the QDs.

Exergy analysis of encapsulation of photochromic dye by spray drying

NASA Astrophysics Data System (ADS)

Çay, A.; Akçakoca Kumbasar, E. P.; Morsunbul, S.

2017-10-01

Application of exergy analysis methodology for encapsulation of photochromic dyes by spray drying was presented. Spray drying system was investigated considering two subsystems, the heater and the dryer sections. Exergy models for each subsystem were proposed and exergy destruction rate and exergy efficiency of each subsystem and the whole system were computed. Energy and exergy efficiency of the system were calculated to be 5.28% and 3.40%, respectively. It was found that 90% of the total exergy inlet was destroyed during encapsulation by spray drying and the exergy destruction of the heater was found to be higher.

Highly efficient enzyme encapsulation in a protein nanocage: towards enzyme catalysis in a cellular nanocompartment mimic

NASA Astrophysics Data System (ADS)

Schoonen, Lise; Nolte, Roeland J. M.; van Hest, Jan C. M.

2016-07-01

The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions.The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions. Electronic supplementary information (ESI) available: Experimental procedures for the cloning, expression, and purification of all proteins, as well as supplementary figures and calculations. See DOI: 10.1039/c6nr04181g

Effects of pore forming agents of potassium bicarbonate and drug loading method against dissolution mechanisms of amoxicillin drugs encapsulated in hydrogel full-Ipn chitosan-poly(N-vinylcaprolactam) as a floating drug delivery system

NASA Astrophysics Data System (ADS)

Aini, Nurul; Rahayu, Dyah Utami Cahyaning; Budianto, Emil

2018-04-01

The limitation of amoxicillin trihydrate in the treatment of H. pylori bacteria is relatively short retention time in the stomach. The FDDS (Floating Drug Delivery System) amoxicillin trihydrate into a chitosan-poly(N-vinylcaprolactam) full-Ipn hydrogel matrix using a pore-forming agent KHCO3 is expected to overcome these limitations. The pore-forming agent to be used is 15% KHCO3 compound. Chemical kinetics approach is performed to determine the dissolution mechanism of amoxicillin trihydrate from K-PNVCL hydrogel in vitro on gastric pH and characterization using SEM performed to confirm the dissolution mechanism. Hydrogels with the addition of pore-forming agents will be loading in situ loading and post loading. Fourier Transform Infra Red (FTIR) spectroscopy was used to characterize K-PNVCL and UV-Vis hydrogels used to calculate the efficiency of encapsulation and drug dissolution rate in K-PNVCL hydrogel. Hydrogel K-PNVCL / KHCO3 that encapsulated by in situ loading method resulted in an encapsulation efficiency of 93.5% and dissolution of 93.4%. While the Hydrogel K-PNVCL / KHCO3 which is drug encapsulation resulted in an encapsulation efficiency of 87.2% with dissolution of 81.5%. Chemical kinetics approach to in situ encapsulation of loading and post loading shows the dissolution mechanism occurring in the K-PNVCL / KHCO3 hydrogel matrix occurs by diffusion. Observation using optical microscope and SEM showed the mechanism of drug dissolution in Hydrogel K-PNVCL occurred by diffusion.

Self-assembly synthesis of 3D graphene-encapsulated hierarchical Fe3O4 nano-flower architecture with high lithium storage capacity and excellent rate capability

NASA Astrophysics Data System (ADS)

Ma, Yating; Huang, Jian; Lin, Liang; Xie, Qingshui; Yan, Mengyu; Qu, Baihua; Wang, Laisen; Mai, Liqiang; Peng, Dong-Liang

2017-10-01

Graphene-encapsulated hierarchical metal oxides architectures can efficiently combine the merits of graphene and hierarchical metal oxides, which are deemed as the potential anode material candidates for the next-generation lithium-ion batteries due to the synergistic effect between them. Herein, a cationic surfactant induced self-assembly method is developed to construct 3D Fe3O4@reduction graphene oxide (H-Fe3O4@RGO) hybrid architecture in which hierarchical Fe3O4 nano-flowers (H-Fe3O4) are intimately encapsulated by 3D graphene network. Each H-Fe3O4 particle is constituted of rod-shaped skeletons surrounded by petal-like nano-flakes that are made up of enormous nanoparticles. When tested as the anode material in lithium-ion batteries, a high reversible capacity of 2270 mA h g-1 after 460 cycles is achieved under a current density of 0.5 A g-1. More impressively, even tested at a large current density of 10 A g-1, a decent reversible capacity of 490 mA h g-1 can be retained, which is still higher than the theoretical capacity of traditional graphite anode, demonstrating the remarkable lithium storage properties. The reasons for the excellent electrochemical performance of H-Fe3O4@RGO electrode have been discussed in detail.

Fabrication of self-assembled chitosan-dispersed LDL nanoparticles for drug delivery with a one-step green method.

PubMed

Tian, Jing; Xu, Shasha; Deng, Hongbing; Song, Xinxing; Li, Xiujuan; Chen, Jiajia; Cao, Feng; Li, Bin

2017-01-30

Self-assembled nanoparticles (NPs) composed of chitosan (CS) and low density lipoprotein (LDL) of hen eggs were prepared by a one-step green synthesis of mixing CS solution and LDL suspension. The formulated CS-LDL NPs were then applied to encapsulate doxorubicin hydrochloride (DOX) with the encapsulation efficiency of 51.7%. The average particle size and ζ-potential of DOX-loaded CS-LDL NPs (CS-LDL-DOX NPs) were 179nm and +48.3mV, respectively. The encapsulated DOX showed less cytotoxicity than free DOX after 24-h incubation with gastric cancer SGC7901 cells, which may be due to extended release. Cellular uptake of CS-LDL-DOX NPs was significant higher than that of free DOX due to the endocytosis of tumor cells. Thus CS-LDL-DOX NPs showed a potential in reducing cytotoxicity of DOX by extended release behavior and preferential uptake compared to free DOX. In addition, flow cytometry and terminal-deoxynucleotidyl-transferase-mediated dUTP nick-end labeling assay demonstrated that CS-LDL-DOX NPs induced the apoptosis of cancer cells. Autophagy was involved in effects caused by CS-LDL-DOX NPs through blocking AKT/mTOR signaling, which was demonstrated by the analyses of the expression of LC3, p62, AKT, p-AKT, mTOR and p-mTOR. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimizing indomethacin-loaded chitosan nanoparticle size, encapsulation, and release using Box-Behnken experimental design.

PubMed

Abul Kalam, Mohd; Khan, Abdul Arif; Khan, Shahanavaj; Almalik, Abdulaziz; Alshamsan, Aws

2016-06-01

Indomethacin chitosan nanoparticles (NPs) were developed by ionotropic gelation and optimized by concentrations of chitosan and tripolyphosphate (TPP) and stirring time by 3-factor 3-level Box-Behnken experimental design. Optimal concentration of chitosan (A) and TPP (B) were found 0.6mg/mL and 0.4mg/mL with 120min stirring time (C), with applied constraints of minimizing particle size (R1) and maximizing encapsulation efficiency (R2) and drug release (R3). Based on obtained 3D response surface plots, factors A, B and C were found to give synergistic effect on R1, while factor A has a negative impact on R2 and R3. Interaction of AB was negative on R1 and R2 but positive on R3. The factor AC was having synergistic effect on R1 and on R3, while the same combination had a negative effect on R2. The interaction BC was positive on the all responses. NPs were found in the size range of 321-675nm with zeta potentials (+25 to +32mV) after 6 months storage. Encapsulation, drug release, and content were in the range of 56-79%, 48-73% and 98-99%, respectively. In vitro drug release data were fitted in different kinetic models and pattern of drug release followed Higuchi-matrix type. Copyright © 2016 Elsevier B.V. All rights reserved.

Microwave-assisted microemulsion technique for production of miconazole nitrate- and econazole nitrate-loaded solid lipid nanoparticles.

PubMed

Shah, Rohan M; Eldridge, Daniel S; Palombo, Enzo A; Harding, Ian H

2017-08-01

The microwave-assisted production of solid lipid nanoparticles (SLNs) is a novel technique reported recently by our group. The small particle size, solid nature and use of physiologically well-tolerated lipid materials make SLNs an interesting and potentially efficacious drug carrier. The main purpose of this research work was to investigate the suitability of microwave-assisted microemulsion technique to encapsulate selected ionic drug substances such as miconazole nitrate and econazole nitrate. The microwave-produced SLNs had a small size (250-300nm), low polydispersity (<0.20), high encapsulation efficiency (72-87%) and loading capacity (3.6-4.3%). Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies suggested reduced crystallinity of stearic acid in SLNs. The release studies demonstrated a slow, sustained but incomplete release of drugs (<60% after 24h) from microwave-produced SLNs. Data fitting of drug release data revealed that the release of both drugs from microwave-produced SLNs was governed by non-Fickian diffusion indicating that drug release was both diffusion- and dissolution- controlled. Anti-fungal efficacy of drug-loaded SLNs was evaluated on C. albicans. The cell viability studies showed that cytotoxicity of SLNs was concentration-dependent. These encouraging results suggest that the microwave-assisted procedure is suitable for encapsulation of ionic drugs and that microwave-produced SLNs can act as potential carriers of antifungal drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Oxidation catalysts on alkaline earth supports

DOEpatents

Mohajeri, Nahid

2017-03-21

An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

Microfluidic approach for encapsulation via double emulsions.

PubMed

Wang, Wei; Zhang, Mao-Jie; Chu, Liang-Yin

2014-10-01

Double emulsions, with inner drops well protected by the outer shells, show great potential as compartmentalized systems to encapsulate multiple components for protecting actives, masking flavor, and targetedly delivering and controllably releasing drugs. Precise control of the encapsulation characteristics of each component is critical to achieve an optimal therapeutic efficacy for pharmaceutical applications. Such controllable encapsulation can be realized by using microfluidic approaches for producing monodisperse double emulsions with versatile and controllable structures as the encapsulation system. The size, number and composition of the emulsion drops can be accurately manipulated for optimizing the encapsulation of each component for pharmaceutical applications. In this review, we highlight the outstanding advantages of controllable microfluidic double emulsions for highly efficient and precisely controllable encapsulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production methodologies of polymeric and hydrogel particles for drug delivery applications.

PubMed

Lima, Ana Catarina; Sher, Praveen; Mano, João F

2012-02-01

Polymeric particles are ideal vehicles for controlled delivery applications due to their ability to encapsulate a variety of substances, namely low- and high-molecular mass therapeutics, antigens or DNA. Micro and nano scale spherical materials have been developed as carriers for therapies, using appropriated methodologies, in order to achieve a prolonged and controlled drug administration. This paper reviews the methodologies used for the production of polymeric micro/nanoparticles. Emulsions, phase separation, spray drying, ionic gelation, polyelectrolyte complexation and supercritical fluids precipitation are all widely used processes for polymeric micro/nanoencapsulation. This paper also discusses the recent developments and patents reported in this field. Other less conventional methodologies are also described, such as the use of superhydrophobic substrates to produce hydrogel and polymeric particulate biomaterials. Polymeric drug delivery systems have gained increased importance due to the need for improving the efficiency and versatility of existing therapies. This allows the development of innovative concepts that could create more efficient systems, which in turn may address many healthcare needs worldwide. The existing methods to produce polymeric release systems have some critical drawbacks, which compromise the efficiency of these techniques. Improvements and development of new methodologies could be achieved by using multidisciplinary approaches and tools taken from other subjects, including nanotechnologies, biomimetics, tissue engineering, polymer science or microfluidics.

Preparation of Robust Metal-Free Magnetic Nanoemulsions Encapsulating Low-Molecular-Weight Nitroxide Radicals and Hydrophobic Drugs Directed Toward MRI-Visible Targeted Delivery.

PubMed

Nagura, Kota; Takemoto, Yusa; Moronaga, Satori; Uchida, Yoshiaki; Shimono, Satoshi; Shiino, Akihiko; Tanigaki, Kenji; Amano, Tsukuru; Yoshino, Fumi; Noda, Yohei; Koizumi, Satoshi; Komatsu, Naoki; Kato, Tatsuhisa; Yamauchi, Jun; Tamura, Rui

2017-11-07

With a view to developing a theranostic nanomedicine for targeted drug delivery systems visible by magnetic resonance (MR) imaging, robust metal-free magnetic nanoemulsions (mean particle size less than 20 nm) consisting of a biocompatible surfactant and hydrophobic, low molecular weight 2,2,5-trimethyl-5-(4-alkoxy)phenylpyrrolidine-N-oxyl radicals were prepared in pH 7.4 phosphate-buffered saline (PBS). The structure of the nanoemulsions was characterized by electron paramagnetic resonance spectroscopy, and dynamic light scattering and small-angle neutron-scattering measurements. The nanoemulsions showed high colloidal stability, low cytotoxicity, enough reduction resistance to excess ascorbic acid, and sufficient contrast enhancement in the proton longitudinal relaxation time (T 1 ) weighted MR images in PBS in vitro (and preliminarily in vivo). Furthermore, the hydrophobic anticancer drug paclitaxel could be encapsulated inside the nanoparticles, and the resulting paclitaxel-loaded nanoemulsions were efficiently incorporated into HeLa cells to suppress cell growth. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical Stability Studies of Semi-Solid Formulations from Natural Compounds Loaded with Chitosan Microspheres

PubMed Central

Acosta, Niuris; Sánchez, Elisa; Calderón, Laura; Cordoba-Diaz, Manuel; Cordoba-Diaz, Damián; Dom, Senne; Heras, Ángeles

2015-01-01

A chitosan-based hydrophilic system containing an olive leaf extract was designed and its antioxidant capacity was evaluated. Encapsulation of olive leaf extract in chitosan microspheres was carried out by a spray-drying process. The particles obtained with this technique were found to be spherical and had a positive surface charge, which is an indicator of mucoadhesiveness. FTIR and X-ray diffraction results showed that there are not specific interactions of polyphenolic compounds in olive leaf extract with the chitosan matrix. Stability and release studies of chitosan microspheres loaded with olive leaf extract before and after the incorporation into a moisturizer base were performed. The resulting data showed that the developed formulations were stable up to three months. The encapsulation efficiency was around 44% and the release properties of polyphenols from the microspheres were found to be pH dependent. At pH 7.4, polyphenols release was complete after 6 h; whereas the amount of polyphenols released was 40% after the same time at pH 5.5. PMID:26389926

Flower-Like ZnO-Assisted One-Pot Encapsulation of Noble Metal Nanoparticles Supported Catalysts with ZIFs

NASA Astrophysics Data System (ADS)

Lin, Lu; Liu, Haiou; Zhang, Xiongfu

2018-03-01

Rational design of efficient approaches to fabricate MOFs-coated core-shell composites is promising but challenging. We report here the encapsulation of Pd nanoparticles (Pd NPs) supported flower-like ZnO (F-ZnO) microspheres with ZIF-8 shell through a facile strategy, in which the formation and immobilization of Pd NPs on F-ZnO supports and the subsequent growth of ZIF-8 shells over them are effectively integrated into one-pot synthetic route. Importantly, the utilization of ZnO both as support of Pd NPs and Zn2+ source of ZIF-8 is favorable for the implement of one-pot synthesis, due to its functions in anchoring Pd NPs and inducing ZIF-8 formation. Further insights into the morphological influence of zinc oxide particles on the resulting materials indicate that the flower-like microspheres with 2D nanosheets as subunits also benefit the coating of Pd NPs supported cores with ZIF-8, resulting in a well-defined core-shell catalyst. The achieved catalyst deliveries remarkable performance in terms of selectivity, anti-poisoning and recyclability in the liquid hydrogenations of alkenes.

Preparation of liquid-core nanocapsules from poly[(ethylene oxide)-co-glycidol] with multiple hydrophobic linoleates at an oil-water interface and its encapsulation of pyrene.

PubMed

Ren, Yong; Wang, Guowei; Huang, Junlian

2007-06-01

A convenient approach is provided to prepare liquid-core nanocapsules by cross-linking an amphiphilic copolymer at an oil-water interface. The hydrophilic copolymer poly[(ethylene oxide)-co-glycidol] was prepared by anionic polymerization of ethylene oxide and ethoxyethyl glycidyl ether first, then the hydroxyl groups on the backbone were recovered after hydrolysis and partly modified by hydrophobic conjugated linoleic acid. The copolymer with multiple linoleate pendants was absorbed at an oil-water interface and then cross-linked to form stable nanocapsules. The mean diameter of the nanocapsule was below 350 nm, and the size distribution was relatively narrow (<0.2) at low concentrations of oil in acetone (<10 mg/mL). The particle size could be tuned easily by variation of the emulsification conditions. The nanocapsule was stable in water for at least 5 months, and the shell maintained its integrity after removal of the oily core by solvent. Pyrene was encapsulated in these nanocapsules, and a loading efficiency as high as 94% was measured by UV spectroscopy.

Nanospheres Encapsulating Anti-Leishmanial Drugs for Their Specific Macrophage Targeting, Reduced Toxicity, and Deliberate Intracellular Release

PubMed Central

Shukla, Anil Kumar; Patra, Sanjukta

2012-01-01

Abstract The current work focuses on the study of polymeric, biodegradable nanoparticles (NPs) for the encapsulation of doxorubicin and mitomycin C (anti-leishmanial drugs), and their efficient delivery to macrophages, the parasite's home. The biodegradable polymer methoxypoly-(ethylene glycol)-b-poly (lactic acid) (MPEG-PLA) was used to prepare polymeric NPs encapsulating doxorubicin and mitomycin C. The morphology, mean diameter, and surface area of spherical NPs were determined by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and BET surface area analysis. X-ray diffraction was performed to validate drug encapsulation. An in vitro release profile of the drugs suggested a fairly slow release. These polymeric NPs were efficiently capable of releasing drug inside macrophages at a slower pace than the free drug, which was monitored by epi-fluorescence microscopy. Encapsulation of doxorubicin and mitomycin C into NPs also decreases cellular toxicity in mouse macrophages (J774.1A). PMID:22925019

A biomimetic hybrid nanoplatform for encapsulation and precisely controlled delivery of therasnostic agents

NASA Astrophysics Data System (ADS)

Wang, Hai; Agarwal, Pranay; Zhao, Shuting; Yu, Jianhua; Lu, Xiongbin; He, Xiaoming

2015-12-01

Nanoparticles have demonstrated great potential for enhancing drug delivery. However, the low drug encapsulation efficiency at high drug-to-nanoparticle feeding ratios and minimal drug loading content in nanoparticle at any feeding ratios are major hurdles to their widespread applications. Here we report a robust eukaryotic cell-like hybrid nanoplatform (EukaCell) for encapsulation of theranostic agents (doxorubicin and indocyanine green). The EukaCell consists of a phospholipid membrane, a cytoskeleton-like mesoporous silica matrix and a nucleus-like fullerene core. At high drug-to-nanoparticle feeding ratios (for example, 1:0.5), the encapsulation efficiency and loading content can be improved by 58 and 21 times, respectively, compared with conventional silica nanoparticles. Moreover, release of the encapsulated drug can be precisely controlled via dosing near infrared laser irradiation. Ultimately, the ultra-high (up to ~87%) loading content renders augmented anticancer capacity both in vitro and in vivo. Our EukaCell is valuable for drug delivery to fight against cancer and potentially other diseases.

Preparation and in vitro evaluation of heparin-loaded polymeric nanoparticles.

PubMed

Jiao, Y Y; Ubrich, N; Marchand-Arvier, M; Vigneron, C; Hoffman, M; Maincent, P

2001-01-01

Nanoparticles of a highly soluble macromolecular drug, heparin, were formulated with two biodegradable polymers (poly-E-caprolactone [PCL] and poly (D, L-lactic-co-glycolic-acid) 50/50 [PLAGA]) and two nonbiodegradable positively charged polymers (Eudragit RS and RL) by the double emulsion and solvent evaporation method, using a high-pressure homogenization device. The encapsulation efficiency and heparin release profiles were studied as a function of the type of polymers employed (alone or in combination) and the concentration of heparin. Optimal encapsulation efficiency was observed when 5000 IU of heparin were incorporated in the first emulsion. High drug entrapment efficiency was observed in both Eudragit RS and RL nanoparticles (60% and 98%, respectively), compared with PLAGA and PCL nanoparticles (<14%). The use of the two types of Eudragit in combination with PCL and PLAGA increased the encapsulation efficiency compared with these two biodegradable polymers used alone; however, the in vitro drug release was not modified and remained low. On the other hand, the addition of esterase to the dissolution medium resulted in a significant increase in heparin release. The in vitro biological activity of released heparin, evaluated by measuring the anti-Xa activity by a colorimetric assay, was conserved after the encapsulation process.

Peptide- and Amine-Modified Glucan Particles for the Delivery of Therapeutic siRNA

PubMed Central

Aouadi, Myriam; Vangala, Pranitha; Tencerova, Michaela; Amano, Shinya U.; Nicoloro, Sarah M.; Yawe, Joseph C.; Czech, Michael P.

2016-01-01

Translation of siRNA technology into the clinic is limited by the need for improved delivery systems that target specific cell types. Macrophages are particularly attractive targets for RNAi therapy because they promote pathogenic inflammatory responses in a number of important human diseases. We previously demonstrated that a multi-component formulation of β-1,3-D-glucan-encapsulated siRNA particles (GeRPs) can specifically and potently silence genes in mouse macrophages. A major advance would be to simplify the GeRP system by reducing the number of delivery components, thus enabling more facile manufacturing and future commercialization. Here we report the synthesis and evaluation of a simplified glucan-based particle (GP) capable of delivering siRNA in vivo to selectively silence macrophage genes. Covalent attachment of small-molecule amines and short peptides containing weak bases to GPs facilitated electrostatic interaction of the particles with siRNA and aided in the endosomal release of siRNA by the proton-sponge effect. Modified GPs were non-toxic and were efficiently internalized by macrophages in vitro. When injected intraperitoneally (i.p.), several of the new peptide-modified GPs were found to efficiently deliver siRNA to peritoneal macrophages in lean, healthy mice. In an animal model of obesity-induced inflammation, i.p. administration of one of the peptide-modified GPs (GP-EP14) bound to siRNA selectively reduced the expression of target inflammatory cytokines in the visceral adipose tissue macrophages. Decreasing adipose tissue inflammation resulted in an improvement of glucose metabolism in these metabolically challenged animals. Thus, modified GPs represent a promising new simplified system for the efficient delivery of therapeutic siRNAs specifically to phagocytic cells in vivo for modulation of inflammation responses. PMID:26815386

Analysis of uniformity of as prepared and irradiated S.I. GaAs radiation detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nava, F.; Vanni, P.; Canali, C.

1998-06-01

SI (semi-insulating) LEC (Liquid Encapsulated Czochralsky) GaAs (gallium arsenide) Schottky barrier detectors have been irradiated with high energy protons (24 GeV/c, fluence up to 16.45 {times} 10{sup 13} p/cm{sup 2}). The detectors have been characterized in terms of I/V curves, charge collection efficiency (cce) for incident 5.48 MeV {alpha}-, 2 MeV proton and minimum ionizing {beta}-particles and of cce maps by microprobe technique IBIC (Ion Beam Induced Charge). At the highest fluence a significant degradation of the electron and hole collection efficiencies and a remarkable improvement of the Full Width Half Maximum (FWHM) energy resolution have been measured with {alpha}-more » and proton particles. Furthermore, the reduction in the cce is greater than the one measured with {beta}-particles and the energy resolution worsens with increasing the applied bias, V{sub a}, above the voltage V{sub d} necessary to extend the electric field al the way to the ohmic contact. On the contrary, in the unirradiated detectors the charge collection efficiencies with {alpha}-, {beta}- and proton particles are quite similar and the energy resolution improves with increasing V{sub a} > V{sub d}. IBIC spectra and IBIC space maps obtained by scanning a focused (8 {micro}m{sup 2}) 2 MeV proton microbeam on front (Schottky) and back (ohmic) contacts, support the observed electric field dependence of the energy resolution both in unirradiated and most irradiated detectors. The results obtained let them explain the effect of the electric field strength and the plasma on the collection of the charge carriers and the FWHM energy resolution.« less

The Poisson distribution and beyond: methods for microfluidic droplet production and single cell encapsulation.

PubMed

Collins, David J; Neild, Adrian; deMello, Andrew; Liu, Ai-Qun; Ai, Ye

2015-09-07

There is a recognized and growing need for rapid and efficient cell assays, where the size of microfluidic devices lend themselves to the manipulation of cellular populations down to the single cell level. An exceptional way to analyze cells independently is to encapsulate them within aqueous droplets surrounded by an immiscible fluid, so that reagents and reaction products are contained within a controlled microenvironment. Most cell encapsulation work has focused on the development and use of passive methods, where droplets are produced continuously at high rates by pumping fluids from external pressure-driven reservoirs through defined microfluidic geometries. With limited exceptions, the number of cells encapsulated per droplet in these systems is dictated by Poisson statistics, reducing the proportion of droplets that contain the desired number of cells and thus the effective rate at which single cells can be encapsulated. Nevertheless, a number of recently developed actively-controlled droplet production methods present an alternative route to the production of droplets at similar rates and with the potential to improve the efficiency of single-cell encapsulation. In this critical review, we examine both passive and active methods for droplet production and explore how these can be used to deterministically and non-deterministically encapsulate cells.

Method for extracting metals from aqueous waste streams for long term storage

DOEpatents

Chaiko, D.J.

1995-03-07

A liquid-liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average individual particle sizes of approximately 40 nanometers. 2 figs.

Method for extracting metals from aqueous waste streams for long term storage

DOEpatents

Chaiko, D.J.

1993-01-01

A liquid-liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average. individual particle sizes of approximately 40 manometers.

Method for extracting metals from aqueous waste streams for long term storage

DOEpatents

Chaiko, David J.

1995-01-01

A liquid--liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average individual particle sizes of approximately 40 nanometers.

A solid colloidal drug delivery system for the eye: encapsulation of pilocarpin in nanoparticles.

PubMed

Harmia, T; Speiser, P; Kreuter, J

1986-01-01

The present study was undertaken in order to encapsulate pilocarpin into nanoparticles. Two principally different methods for manufacturing these particles were investigated. Firstly, pilocarpin was dissolved in an aqueous medium in which the polymerization was carried out, and secondly, the polymerizing monomer was kept saturated with the drug solution under acidic conditions resulting in an incorporation into the nanoparticles in an aqueous environment. The amount of pilocarpin that could be incorporated into the nanoparticles was found to be largely influenced by the temperature at which the nanoparticles were produced and by the stabilizers used. At low temperatures, up to 60 per cent of pilocarpin nitrate could be encapsulated into butylcyanoacrylate nanoparticles using emulsion polymerization techniques. Larger amounts of pilocarpin could not be incorporated because of the hydrophilicity of the salts of this drug. The physico-chemical characteristics of the nanoparticles are reported: the particle size and morphology were determined by scanning and transmission electron microscopy and photon correlation spectrometry. The average particle size was about 100 nm. The results obtained in this study show that photon correlation spectrometry is a suitable method for the sizing of nanoparticles.

Design and characterization of emulsified spray dried alginate microparticles as a carrier for the dually acting drug roflumilast.

PubMed

Mahmoud, Azza A; Elkasabgy, Nermeen A; Abdelkhalek, Abdel Fatah A

2018-06-18

Roflumilast is a selective inhibitor of phosphodiesterase-4 isoenzyme in lung cells. Having psychiatric adverse reactions when administered orally affects negatively the patients' adherence to the drug. This work aimed to prepare emulsified spray dried alginate microparticles for the pulmonary delivery of roflumilast. Sodium alginate was used as microparticle-forming material, isopropyl myristate as an oil, Tween®80 as surfactant and calcium beta-glycerophosphate as cross-linking agent to enhance the mechanical properties of the particles. The prepared particles were evaluated for their encapsulation efficiency, particle size and in-vitro release. From the studied carriers, beta-cyclodextrin (CD) was the best regarding giving formulation smaller particle size and more sustained drug release. The inhalation profile of CD-based microparticles was investigated using Anderson cascade impactor. The aerosolization profile of CD-based microparticles suggested their efficiency to deliver the drug deep in the lung. The CD-based microparticles possessed more inhibitory effects on the viability of A549 cells and on the pro-inflammatory cytokines (TNF-α, IL-6 and IL-10) compared to the pure drug. Hence, CD-based microparticles could regulate the tumorigenesis besides tumor-associated inflammation. Finally, CD-based microparticles showed more sustained bronchodilatation properties in healthy human volunteers when compared to Ventolin®HFA. CD-based microparticles proved to be a promising carrier for inhaled roflumilast in human. Copyright © 2018. Published by Elsevier B.V.

Development of DBD plasma actuators: The double encapsulated electrode

NASA Astrophysics Data System (ADS)

Erfani, Rasool; Zare-Behtash, Hossein; Hale, Craig; Kontis, Konstantinos

2015-04-01

Plasma actuators are electrical devices that generate a wall bounded jet without the use of any moving parts. For aerodynamic applications they can be used as flow control devices to delay separation and augment lift on a wing. The standard plasma actuator consists of a single encapsulated (ground) electrode. The aim of this project is to investigate the effect of varying the number and distribution of encapsulated electrodes in the dielectric layer. Utilising a transformer cascade, a variety of input voltages are studied for their effect. In the quiescent environment of a Faraday cage the velocity flow field is recorded using particle image velocimetry. Through understanding of the mechanisms involved in producing the wall jet and the importance of the encapsulated electrode a novel actuator design is proposed. The actuator design distributes the encapsulated electrode throughout the dielectric layer. The experiments have shown that actuators with a shallow initial encapsulated electrode induce velocities greater than the baseline case at the same voltage. Actuators with a deep initial encapsulated electrode are able to induce the highest velocities as they can operate at higher voltages without breakdown of the dielectric.

In vitro determination of the efficacy of scorpion venoms as anti-cancer agents against colorectal cancer cells: a nano-liposomal delivery approach.

PubMed

Al-Asmari, Abdulrahman K; Ullah, Zabih; Al Balowi, Ali; Islam, Mozaffarul

2017-01-01

The use of liposomes in biological and medicinal sciences is a relatively new approach. The liposomal strategy greatly depends on the technological advancement in the formation of vesicles of various sizes and properties. In the current study, we encapsulated the venoms obtained from medically important scorpions such as Androctonus bicolor (AB), Androctonus crassicauda (AC), and Leiurus quinquestriatus (LQ). To begin with, our first and foremost aim was to prepare biocompatible and biodegradable nanovesicles. Additionally, we intended to enhance the anti-cancer potential of these encapsulated venoms. The liposomal venoms were prepared by rehydration and dehydration methods. Morphology, particle size, and size distribution of the liposomes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Zetasizer. We found that the prepared liposomes had a smooth surface and a spherical/ovoid shape and existed mainly as single unilamellar vesicles (SUVs). Furthermore, the liposomal formulation of all three venoms exhibited excellent stability and good encapsulation efficiency (EE). Additionally, the anti-cancer potential of the encapsulated venoms was also evaluated on a colorectal cancer cell line (HCT-8). The venom-loaded liposomes showed elevated anti-cancer properties such as low rate of cell survival, higher reactive oxygen species (ROS) generation, and enhancement in the number of apoptotic cells. In addition to this, cell cycle analysis revealed G0/G1 enrichment upon venom treatment. The effect of treatment was more pronounced when venom-liposome was used as compared to free venom on the HCT-8 cell line. Furthermore, we did not observe any interference of liposomal lipids used in these preparations on the progression of cancer cells. Considering these findings, we can conclude that the encapsulated scorpion venoms exhibit better efficacy and act more vigorously as an anti-cancer agent on the colorectal cancer cell line when compared with their free counterpart.

In vitro determination of the efficacy of scorpion venoms as anti-cancer agents against colorectal cancer cells: a nano-liposomal delivery approach

PubMed Central

Al-Asmari, Abdulrahman K; Ullah, Zabih; Al Balowi, Ali; Islam, Mozaffarul

2017-01-01

The use of liposomes in biological and medicinal sciences is a relatively new approach. The liposomal strategy greatly depends on the technological advancement in the formation of vesicles of various sizes and properties. In the current study, we encapsulated the venoms obtained from medically important scorpions such as Androctonus bicolor (AB), Androctonus crassicauda (AC), and Leiurus quinquestriatus (LQ). To begin with, our first and foremost aim was to prepare biocompatible and biodegradable nanovesicles. Additionally, we intended to enhance the anti-cancer potential of these encapsulated venoms. The liposomal venoms were prepared by rehydration and dehydration methods. Morphology, particle size, and size distribution of the liposomes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Zetasizer. We found that the prepared liposomes had a smooth surface and a spherical/ovoid shape and existed mainly as single unilamellar vesicles (SUVs). Furthermore, the liposomal formulation of all three venoms exhibited excellent stability and good encapsulation efficiency (EE). Additionally, the anti-cancer potential of the encapsulated venoms was also evaluated on a colorectal cancer cell line (HCT-8). The venom-loaded liposomes showed elevated anti-cancer properties such as low rate of cell survival, higher reactive oxygen species (ROS) generation, and enhancement in the number of apoptotic cells. In addition to this, cell cycle analysis revealed G0/G1 enrichment upon venom treatment. The effect of treatment was more pronounced when venom–liposome was used as compared to free venom on the HCT-8 cell line. Furthermore, we did not observe any interference of liposomal lipids used in these preparations on the progression of cancer cells. Considering these findings, we can conclude that the encapsulated scorpion venoms exhibit better efficacy and act more vigorously as an anti-cancer agent on the colorectal cancer cell line when compared with their free counterpart. PMID:28144138

Encapsulation of enzyme via one-step template-free formation of stable organic-inorganic capsules: A simple and efficient method for immobilizing enzyme with high activity and recyclability.

PubMed

Huang, Renliang; Wu, Mengyun; Goldman, Mark J; Li, Zhi

2015-06-01

Enzyme encapsulation is a simple, gentle, and general method for immobilizing enzyme, but it often suffers from one or more problems regarding enzyme loading efficiency, enzyme leakage, mechanical stability, and recyclability. Here we report a novel, simple, and efficient method for enzyme encapsulation to overcome these problems by forming stable organic-inorganic hybrid capsules. A new, facile, one-step, and template-free synthesis of organic-inorganic capsules in aqueous phase were developed based on PEI-induced simultaneous interfacial self-assembly of Fmoc-FF and polycondensation of silicate. Addition of an aqueous solution of Fmoc-FF and sodium silicate into an aqueous solution of PEI gave a new class of organic-inorganic hybrid capsules (FPSi) with multi-layered structure in high yield. The capsules are mechanically stable due to the incorporation of inorganic silica. Direct encapsulation of enzyme such as epoxide hydrolase SpEH and BSA along with the formation of the organic-inorganic capsules gave high yield of enzyme-containing capsules (∼1.2 mm in diameter), >90% enzyme loading efficiency, high specific enzyme loading (158 mg protein g(-1) carrier), and low enzyme leakage (<3% after 48 h incubation). FPSi-SpEH capsules catalyzed the hydrolysis of cyclohexene oxide to give (1R, 2R)-cyclohexane-1,2-diol in high yield and concentration, with high specific activity (6.94 U mg(-1) protein) and the same high enantioselectivity as the free enzyme. The immobilized SpEH demonstrated also excellent operational stability and recyclability: retaining 87% productivity after 20 cycles with a total reaction time of 80 h. The new enzyme encapsulation method is efficient, practical, and also better than other reported encapsulation methods. © 2015 Wiley Periodicals, Inc.

Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery

PubMed Central

Lu, Ying; Sturek, Michael; Park, Kinam

2014-01-01

Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2 % and 92 % for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles. PMID:24333903

Transcriptional transactivator peptide modified lidocaine-loaded nanoparticulate drug delivery system for topical anesthetic therapy.

PubMed

Wang, Yan; Wang, Shenhui; Shi, Pengcai

2016-11-01

For the topical anesthetic, transcriptional transactivator peptide (TAT) modified lidocaine (LID) loaded nanostructured lipid carriers (TAT-NLCs-LID) were prepared and then used for improving transdermal delivery of local anesthetic drug. In this study, TAT was conjugated with Distearoyl phosphatidylethanolamine-(polyethylene glycol) 2000 -maleimide (DSPE-PEG 2000 -Mal) to obtain TAT-PEG 2000 -DSPE. TAT-NLCs-LID were successfully prepared and characterized by determination of their particle size, morphology, drug encapsulation efficiency and in vitro drug release behavior. The skin permeation of LID-LNPs was examined using a Franz diffusion cell mounted with depilated mouse skin in vitro and in vivo anesthesia effect was evaluated on mice. The results showed that TAT-NLCs-LID have substantially small mean diameter (157.9 nm) and high encapsulation efficiency (81.8%). From the in vitro skin permeation results, transdermal flux of TAT-NLCs-LID was about several times higher than that of LID solution and NLCs-LID. In vivo anesthesia effect evaluation illustrated that TAT-NLCs-LID can enhance the transdermal delivery of LID by reducing the pain threshold in mice. These results indicate that the novel TAT containing drug delivery system is very useful for overcoming the barrier function of the skin and could deliver anesthetic through the skin. TAT-NLCs-LID could function as promising topical anesthetic system.

Development of pH Sensitive Nanoparticles for Intestinal Drug Delivery Using Chemically Modified Guar Gum Co-Polymer.

PubMed

Varma, Vegesna Naga Sravan Kumar; Shivakumar, Hosakote Gurumalappa; Balamuralidhara, Veerna; Navya, Manne; Hani, Umme

2016-01-01

The aim of the research work was to chemically modify guargum (GG) as a pH sensitive co-polymer and formulating intestinal targeting ESO nanoparticles (NPs) using the synthesized co-polymer. Poly acrylamide-grafted-guar gum (PAAm-g-GG) co-polymer was synthesized by free radical polymerization. Chemical modification of PAAm-g-GG by alkaline hydrolysis results in formation of a pH-sensitive co-polymer. The effect of GG and acryl amide (AAm) on grafting was studied. Esomeprazole magnesium (ESO) loaded pH sensitive NPs were prepared by nano-emulsification polymer crosslinking method and characterized. Sixteen formulations were prepared and the concentration of process variables wasvaried to obtain nanoparticles of 200-600 nm. The NPs were found to be homogenous in size distribution. The encapsulation efficiency and drug loading ranged from 33.2% to 50.1% and 12.2% to 17.2% respectively. Particle size, encapsulation efficiency and drug loading increasedalong with co-polymer concentration. In-vitro release studies at pH 1.2 for 2 h, followed by pH 6.8 showed that environment pH significantly affected the drug release. SEM has shown that NPsare spherical with smooth surface. The pH sensitive PAAm-g-GGNPs resisted the initial release of the drug from the drug loaded NPs in acidic pH and delayed the release process to a longer period in alkaline environment.

Development of pH Sensitive Nanoparticles for Intestinal Drug Delivery Using Chemically Modified Guar Gum Co-Polymer

PubMed Central

Varma, Vegesna Naga Sravan Kumar; Shivakumar, Hosakote Gurumalappa; Balamuralidhara, Veerna; Navya, Manne; Hani, Umme

2016-01-01

The aim of the research work was to chemically modify guargum (GG) as a pH sensitive co-polymer and formulating intestinal targeting ESO nanoparticles (NPs) using the synthesized co-polymer. Poly acrylamide-grafted-guar gum (PAAm-g-GG) co-polymer was synthesized by free radical polymerization. Chemical modification of PAAm-g-GG by alkaline hydrolysis results in formation of a pH-sensitive co-polymer. The effect of GG and acryl amide (AAm) on grafting was studied. Esomeprazole magnesium (ESO) loaded pH sensitive NPs were prepared by nano-emulsification polymer crosslinking method and characterized. Sixteen formulations were prepared and the concentration of process variables wasvaried to obtain nanoparticles of 200-600 nm. The NPs were found to be homogenous in size distribution. The encapsulation efficiency and drug loading ranged from 33.2% to 50.1% and 12.2% to 17.2% respectively. Particle size, encapsulation efficiency and drug loading increasedalong with co-polymer concentration. In-vitro release studies at pH 1.2 for 2 h, followed by pH 6.8 showed that environment pH significantly affected the drug release. SEM has shown that NPsare spherical with smooth surface. The pH sensitive PAAm-g-GGNPs resisted the initial release of the drug from the drug loaded NPs in acidic pH and delayed the release process to a longer period in alkaline environment. PMID:27610149

Improved insulin loading in poly(lactic-co-glycolic) acid (PLGA) nanoparticles upon self-assembly with lipids.

PubMed

García-Díaz, María; Foged, Camilla; Nielsen, Hanne Mørck

2015-03-30

Polymeric nanoparticles are widely investigated as drug delivery systems for oral administration. However, the hydrophobic nature of many polymers hampers effective loading of the particles with hydrophilic macromolecules such as insulin. Thus, the aim of this work was to improve the loading of insulin into poly(lactic-co-glycolic) acid (PLGA) nanoparticles by pre-assembly with amphiphilic lipids. Insulin was complexed with soybean phosphatidylcholine or sodium caprate by self-assembly and subsequently loaded into PLGA nanoparticles by using the double emulsion-solvent evaporation technique. The nanoparticles were characterized in terms of size, zeta potential, insulin encapsulation efficiency and loading capacity. Upon pre-assembly with lipids, there was an increased distribution of insulin into the organic phase of the emulsion, eventually resulting in significantly enhanced encapsulation efficiencies (90% as compared to 24% in the absence of lipids). Importantly, the insulin loading capacity was increased up to 20% by using the lipid-insulin complexes. The results further showed that a main fraction of the lipid was incorporated into the nanoparticles and remained associated to the polymer during release studies in buffers, whereas insulin was released in a non-complexed form as a burst of approximately 80% of the loaded insulin. In conclusion, the protein load in PLGA nanoparticles can be significantly increased by employing self-assembled protein-lipid complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and evaluation of nanoparticles based on mPEG-PLA for controlled delivery of vinpocetine: in vitro and in vivo studies.

PubMed

Wang, Run; Xu, Yong

2017-02-01

The aim of present study was to develop VIN-loaded mPEG-PLA nanoparticle systems. The VIN mPEG-PLA nanoparticles were prepared using an emulsion solvent evaporation method, and studied their particle size, morphology, encapsulation efficiency and drug-loading coefficient. Moreover, the nanoparticles were evaluated on the drug release behaviors in vitro and bioavailability in vivo. The results show that the spherical nanoparticles obtained were negatively charged with a zeta potential of about -23.4 mV and characterized ∼110 nm with a narrow size distribution. The encapsulation efficiency and drug loading of prepared NPs were 76.4 ± 6.3 and 9.2 ± 2.2% (n=5), respectively. The in vitro release showed that the percent of accumulated dissolution of VIN NPs in phosphate-buffered saline 6.8 over 24 h was <80%, which was almost 100% of VIN in commercial injections. The in vivo study indicated that systemic absorption of VIN was significantly enhanced by incorporating into mPEG-PLA NPs compared with VIN injection (2.87-fold in AUC 0- t ). The results suggested that the form of VIN in mPEG-PLA NPs could enter the body circulation to perform sustained release in vitro and in vivo.

Formation of methotrexate-PLLA-PEG-PLLA composite microspheres by microencapsulation through a process of suspension-enhanced dispersion by supercritical CO2

PubMed Central

Chen, Ai-Zheng; Wang, Guang-Ya; Wang, Shi-Bin; Li, Li; Liu, Yuan-Gang; Zhao, Chen

2012-01-01

Background The aim of this study was to improve the drug loading, encapsulation efficiency, and sustained-release properties of supercritical CO2-based drug-loaded polymer carriers via a process of suspension-enhanced dispersion by supercritical CO2 (SpEDS), which is an advanced version of solution-enhanced dispersion by supercritical CO2 (SEDS). Methods Methotrexate nanoparticles were successfully microencapsulated into poly (L-lactide)-poly(ethylene glycol)-poly(L-lactide) (PLLA-PEG-PLLA) by SpEDS. Methotrexate nanoparticles were first prepared by SEDS, then suspended in PLLA-PEG-PLLA solution, and finally microencapsulated into PLLA-PEG-PLLA via SpEDS, where an “injector” was utilized in the suspension delivery system. Results After microencapsulation, the composite methotrexate (MTX)-PLLA-PEG-PLLA microspheres obtained had a mean particle size of 545 nm, drug loading of 13.7%, and an encapsulation efficiency of 39.2%. After an initial burst release, with around 65% of the total methotrexate being released in the first 3 hours, the MTX-PLLA-PEG-PLLA microspheres released methotrexate in a sustained manner, with 85% of the total methotrexate dose released within 23 hours and nearly 100% within 144 hours. Conclusion Compared with a parallel study of the coprecipitation process, microencapsulation using SpEDS offered greater potential to manufacture drug-loaded polymer microspheres for a drug delivery system. PMID:22787397

Development and evaluation of paclitaxel nanoparticles using a quality-by-design approach.

PubMed

Yerlikaya, Firat; Ozgen, Aysegul; Vural, Imran; Guven, Olgun; Karaagaoglu, Ergun; Khan, Mansoor A; Capan, Yilmaz

2013-10-01

The aims of this study were to develop and characterize paclitaxel nanoparticles, to identify and control critical sources of variability in the process, and to understand the impact of formulation and process parameters on the critical quality attributes (CQAs) using a quality-by-design (QbD) approach. For this, a risk assessment study was performed with various formulation and process parameters to determine their impact on CQAs of nanoparticles, which were determined to be average particle size, zeta potential, and encapsulation efficiency. Potential risk factors were identified using an Ishikawa diagram and screened by Plackett-Burman design and finally nanoparticles were optimized using Box-Behnken design. The optimized formulation was further characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, and gas chromatography. It was observed that paclitaxel transformed from crystalline state to amorphous state while totally encapsulating into the nanoparticles. The nanoparticles were spherical, smooth, and homogenous with no dichloromethane residue. In vitro cytotoxicity test showed that the developed nanoparticles are more efficient than free paclitaxel in terms of antitumor activity (more than 25%). In conclusion, this study demonstrated that understanding formulation and process parameters with the philosophy of QbD is useful for the optimization of complex drug delivery systems. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-08-31

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-12-01

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017. Published by Elsevier B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

LAGASSE,ROBERT R.; THOMPSON,KYLE R.

The goal of this work is to develop techniques for measuring gradients in particle concentration within filled polymers, such as encapsulant. A high concentration of filler particles is added to such materials to tailor physical properties such as thermal expansion coefficient. Sedimentation and flow-induced migration of particles can produce concentration gradients that are most severe near material boundaries. Therefore, techniques for measuring local particle concentration should be accurate near boundaries. Particle gradients in an alumina-filled epoxy resin are measured with a spatial resolution of 0.2 mm using an x-ray beam attenuation technique, but an artifact related to the finite diametermore » of the beam reduces accuracy near the specimen's edge. Local particle concentration near an edge can be measured more reliably using microscopy coupled with image analysis. This is illustrated by measuring concentration profiles of glass particles having 40 {micro}m median diameter using images acquired by a confocal laser fluorescence microscope. The mean of the measured profiles of volume fraction agrees to better than 3% with the expected value, and the shape of the profiles agrees qualitatively with simple theory for sedimentation of monodisperse particles. Extending this microscopy technique to smaller, micron-scale filler particles used in encapsulant for microelectronic devices is illustrated by measuring the local concentration of an epoxy resin containing 0.41 volume fraction of silica.« less

Encapsulation efficiency of CdSe/ZnS quantum dots by liposomes determined by thermal lens microscopy

PubMed Central

Batalla, Jessica; Cabrera, Humberto; San Martín-Martínez, Eduardo; Korte, Dorota; Calderón, Antonio; Marín, Ernesto

2015-01-01

In this study the encapsulation of core shell carboxyl CdSe/ZnS quantum dots (QDs) by phospholipids liposome complexes is presented. It makes the quantum dots water soluble and photo-stable. Fluorescence self-quenching of the QDs inside the liposomes was observed. Therefore, the thermal lens microscopy (TLM) was found to be an useful tool for measuring the encapsulation efficiency of the QDs by the liposomes, for which an optimum value of 36% was determined. The obtained limit of detection (LOD) for determining QDs concentration by TLM was 0.13 nM. Moreover, the encapsulated QDs showed no prominent cytotoxicity toward Breast cancer cells line MDA-MB-231. This study was supported by UV-visible spectroscopy, high resolution transmission electron microscopy (HRTEM) and dynamic light scattering measurements (DLS). PMID:26504640

Encapsulation of docetaxel into PEGylated gold nanoparticles for vectorization to cancer cells.

PubMed

François, Alison; Laroche, Audrey; Pinaud, Noël; Salmon, Lionel; Ruiz, Jaime; Robert, Jacques; Astruc, Didier

2011-11-04

Encapsulation of docetaxel and its solubilization in water was carried out in PEGylated gold nanoparticles (AuNPs) as shown by 1H NMR (600 MHz) and UV/Vis spectroscopy and dynamic light scattering. Vectorization of PEGylated AuNP-encapsulated docetaxel was probed in vitro toward human colon carcinoma (HCT15) and human breast cancer (MCF7) cells. AuNPs alone presented no cytotoxicity toward either MCF7 or HCT15 adenocarcinoma cells. AuNP-docetaxel was found to be 2.5-fold more efficient than docetaxel alone against MCF7 cells, and the IC50 value of AuNP-docetaxel against HCT15 cells was lower than that of free docetaxel; the increased efficiency brought about by AuNP drug encapsulation was ∼1.5-fold. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced encapsulation of metoprolol tartrate with carbon nanotubes as adsorbent

NASA Astrophysics Data System (ADS)

Garala, Kevin; Patel, Jaydeep; Patel, Anjali; Dharamsi, Abhay

2011-12-01

A highly water-soluble antihypertensive drug, metoprolol tartrate (MT), was selected as a model drug for preparation of multi-walled carbon nanotubes (MWCNTs)-impregnated ethyl cellulose (EC) microspheres. The present investigation was aimed to increase encapsulation efficiency of MT with excellent adsorbent properties of MWCNTs. The unique surface area, stiffness, strength and resilience of MWCNTs have drawn much anticipation as carrier for highly water-soluble drugs. Carbon nanotubes drug adsorbate (MWCNTs:MT)-loaded EC microspheres were further optimized by the central composite design of the experiment. The effects of independent variables (MWCNTs:MT and EC:adsorbate) were evaluated on responses like entrapment efficiency (EE) and t 50 (time required for 50% drug release). The optimized batch was compared with drug alone EC microspheres. The results revealed high degree of improvement in encapsulation efficiency for MWCNTs:MT-loaded EC microspheres. In vitro drug release study exhibited complete release form drug alone microspheres within 15 h, while by the same time only 50-60% drug was released for MWCNTs-impregnated EC microspheres. The optimized batch was further characterized by various instrumental analyses such as scanning electron microscopy, powder X-ray diffraction and differential scanning calorimetry. The results endorse encapsulation of MWCNTs:MT adsorbate inside the matrix of EC microspheres, which might have resulted in enhanced encapsulation and sustained effect of MT. Hence, MWCNTs can be utilized as novel carriers for extended drug release and enhanced encapsulation of highly water-soluble drug, MT.

Production of solid lipid submicron particles for protein delivery using a novel supercritical gas-assisted melting atomization process.

PubMed

Salmaso, Stefano; Elvassore, Nicola; Bertucco, Alberto; Caliceti, Paolo

2009-02-01

A supercritical carbon dioxide micronization technique based on gas-assisted melting atomization has been designed to prepare protein-loaded solid lipid submicron particles. The supercritical process was applied to homogeneous dispersions of insulin in lipid mixtures: (1) tristearin, Tween-80, phosphatidylcholine and 5 kDa PEG (1:0.1:0.9:1 and 1:0.1:0.9:2 weight ratio); and (2) tristearin, dioctyl sulfosuccinate and phosphatidylcholine (1:1:0.5 weight ratio). Optimized process conditions yielded dry nonagglomerated powders with high product recovery (70%, w/w). Dynamic light scattering and transmission electron microscopy showed that two size fractions of particles, with 80-120 and 200-400 nm diameters, were produced. In all final products, dimethylsulfoxide used to prepare the insulin/lipid mixture was below 20 ppm. Protein encapsulation efficiency increased up to 80% as the DMSO content in the insulin/lipid mixture increased. Compared to the particles without PEG, the polymer-containing particles dispersed rapidly in water, and the dispersions were more stable under centrifugation as less than 20% of suspended particles precipitated after extensive centrifugation. In vitro, the protein was slowly released from the formulation without PEG, while a burst and faster release were obtained from the formulations containing PEG. Subcutaneous injection to diabetic mice of insulin extracted from the particles showed that the supercritical process did not impair the protein hypoglycemic activity.

Optimisation of preparation conditions and properties of phytosterol liposome-encapsulating nattokinase.

PubMed

Dong, Xu-Yan; Kong, Fan-Pi; Yuan, Gang-You; Wei, Fang; Jiang, Mu-Lan; Li, Guang-Ming; Wang, Zhan; Zhao, Yuan-Di; Chen, Hong

2012-01-01

Phytosterol liposomes were prepared using the thin film method and used to encapsulate nattokinase (NK). In order to obtain a high encapsulation efficiency within the liposome, an orthogonal experiment (L9 (3)(4)) was applied to optimise the preparation conditions. The molar ratio of lecithin to phytosterols, NK activity and mass ratio of mannite to lecithin were the main factors that influenced the encapsulation efficiency of the liposomes. Based on the results of a single-factor test, these three factors were chosen for this study. We determined the optimum extraction conditions to be as follows: a molar ratio of lecithin to phytosterol of 2 : 1, NK activity of 2500 U mL⁻¹ and a mass ratio of mannite to lecithin of 3 : 1. Under these optimised conditions, an encapsulation efficiency of 65.25% was achieved, which agreed closely with the predicted result. Moreover, the zeta potential, size distribution and microstructure of the liposomes prepared were measured, and we found that the zeta potential was -51 ± 3 mV and the mean diameter was 194.1 nm. From the results of the scanning electron microscopy, we observed that the phytosterol liposomes were round and regular in shape and showed no aggregation.

Effect of drug loading method against the dissolution mechanism of encapsulated amoxicillin trihidrate drug in matrix of semi-IPN chitosan-poly (N-vinyl pyrrolidone) hydrogel with pore forming agent CaCO3

NASA Astrophysics Data System (ADS)

Nurjannah, Yanah; Budianto, Emil

2018-04-01

Heliobacter pylori (H.pylori) is a type of bacteria that causes inflammation in the lining of the stomach. The treatment of the bacterial infection by using conventional medicine which is amoxicillin trihidrate has a very short retention time in the stomach which is about 1-1,5 hours. Floating drug delivery system is expected to have a long retention time in the stomach so the efficiency of drug can be achieved. In this study, has been synthesized matrix of semi-IPN chitosan-Poly(N-vinil pyrrolidone) hydrogel with a pore-forming agent of CaCO3 under optimum conditions. Amoxicillin is encapsulated in a matrix hydrogel to be applied as a floating drug delivery system by in situ loading and post loading methods. The encapsulation efficiency and dissolution of in situ loading and post loading hydrogels are performed in vitro on gastric pH. In situ loading hydrogel shows higer percentage of encapsulation efficiency and dissolution compared to post loading hydrogel. The encapsulation efficiency of in situ and post loading hydrogels were 92,1% and 89,4%, respectively. The aim of drug dissolution by mathematical equation model is to know kinetics and the mecanism of dissolution. The kinetics release of in situ hydrogel tends to follow first order kinetics, while the post loading hydrogel follow the Higuchi model. The dissolution mecanism of hydrogels is erosion.

Antibiotic release from biodegradable PHBV microparticles.

PubMed

Sendil, D; Gürsel, I; Wise, D L; Hasirci, V

1999-05-20

For the treatment of periodontal diseases, design of a controlled release system seemed very appropriate for an effective, long term result. In this study a novel, biodegradable microbial polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV of various valerate contents containing a well established antibiotic, tetracycline, known to be effective against many of the periodontal disease related microorganisms, was used in the construction of a controlled release system. Tetracycline was loaded in the PHBV microspheres and microcapsules both in its acidic (TC) and in neutral form (TCN). Microcapsules of PHBV were prepared under different conditions using w/o/w double emulsion and their properties such as encapsulation efficiency, loading, release characteristics, and morphological properties were investigated. It was found that concentration of emulsifiers polyvinyl alcohol (PVA) and gelatin (varied between 0-4%) influenced the encapsulation efficiency appreciably. In order to increase encapsulation efficiency (from the obtained range of 18.1-30.1%) and slow down the release of the highly soluble tetracycline.HCl, it was neutralized with NaOH. Encapsulation efficiency of neutralized tetracycline was much higher (51.9-65.3%) due to the insoluble form of the drug used during encapsulation. The release behaviour of neither of the drugs was found to be of zero order. Rather the trends fitted reasonably well to Higuchi's approach for release from spherical micropheres. Biodegradability was not an appreciable parameter in the release from microcapsules because release was complete before any signs of degradation were observed.

Bioadhesive chitosan-coated cyclodextrin-based superamolecular nanomicelles to enhance the oral bioavailability of doxorubicin

NASA Astrophysics Data System (ADS)

Liu, Yuhai; Zhai, Yinglei; Han, Xiaopeng; Liu, Xiaohong; Liu, Wanjun; Wu, Chunnuan; Li, Lin; Du, Yuqian; Lian, He; Wang, Yongjun; He, Zhonggui; Sun, Jin

2014-10-01

In order to improve the oral bioavailability of doxorubicin (Dox), a novel bioadhesive nanomicelle based on host-guest interaction was developed in this study. Hyaluronic acid-linked β-cyclodextrin (HA-CD) was synthesized. The primary nanomicelles were formed through the self-assemble of HA-CD and retinoic acid (RA) which was included as the hydrophobic core to anchor CD cavity by host-guest interaction. Chitosan (CS) was then coated on the surface of primary nanomicelles by ionic interaction with the negatively charged HA. The critical micellar concentration of HA-CD-RA was as low as 22.5 μg/mL. Dox was successfully encapsulated into the hydrophobic core of CS-coated HA-CD-RA nanomicelles (CS/HA-CD-RA-Dox), with encapsulation efficiency as high as 89.2 %. The CS/HA-CD-RA-Dox particle size was 234 nm and was stable over 30 days. In vitro Dox release showed that CS/HA-CD-RA nanomicelles were more sustained than HA-CD-RA nanomicelles, and Dox encapsulated into CS-coated nanomicelles was stable at low pH. The in situ single pass intestinal perfusion revealed that encapsulation of Dox into CS/HA-CD-RA nanomicelles could significantly improve the intestinal permeability of Dox. The mucoadhesion results indicated that the retention percentage of CS/HA-CD-RA nanomicelles was significantly higher than that of HA-CD-RA nanomicelles in gastrointestinal tract. In vivo pharmacokinetic study revealed that AUC(0-∞) of CS/HA-CD-RA nanomicelles was about fourfold higher than that of Dox solution. The present study suggested that CS/HA-CD-RA nanomicelles as biodegradable, biocompatible, and bioadhesive nanostructure can be a promising nanocarrier in improving the bioavailability of anticancer drugs to facilitate the oral chemotherapy.

Preserving catalytic activity and enhancing biochemical stability of the therapeutic enzyme asparaginase by biocompatible multilayered polyelectrolyte microcapsules.

PubMed

Karamitros, Christos S; Yashchenok, Alexey M; Möhwald, Helmuth; Skirtach, Andre G; Konrad, Manfred

2013-12-09

The present study focuses on the formation of microcapsules containing catalytically active L-asparaginase (L-ASNase), a protein drug of high value in antileukemic therapy. We make use of the layer-by-layer (LbL) technique to coat protein-loaded calcium carbonate (CaCO3) particles with two or three poly dextran/poly-L-arginine-based bilayers. To achieve high loading efficiency, the CaCO3 template was generated by coprecipitation with the enzyme. After assembly of the polymer shell, the CaCO3 core material was dissolved under mild conditions by dialysis against 20 mM EDTA. Biochemical stability of the encapsulated L-asparaginase was analyzed by treating the capsules with the proteases trypsin and thrombin, which are known to degrade and inactivate the enzyme during leukemia treatment, allowing us to test for resistance against proteolysis by physiologically relevant proteases through measurement of residual l-asparaginase activities. In addition, the thermal stability, the stability at the physiological temperature, and the long-term storage stability of the encapsulated enzyme were investigated. We show that encapsulation of l-asparaginase remarkably improves both proteolytic resistance and thermal inactivation at 37 °C, which could considerably prolong the enzyme's in vivo half-life during application in acute lymphoblastic leukemia (ALL). Importantly, the use of low EDTA concentrations for the dissolution of CaCO3 by dialysis could be a general approach in cases where the activity of sensitive biomacromolecules is inhibited, or even irreversibly damaged, when standard protocols for fabrication of such LbL microcapsules are used. Encapsulated and free enzyme showed similar efficacies in driving leukemic cells to apoptosis.

Preparation and characterization of monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) micelles for the solubilization and in vivo delivery of luteolin

PubMed Central

Qiu, Jin-Feng; Gao, Xiang; Wang, Bi-Lan; Wei, Xia-Wei; Gou, Ma-Ling; Men, Ke; Liu, Xing-Yu; Guo, Gang; Qian, Zhi-Yong; Huang, Mei-Juan

2013-01-01

Luteolin (Lu) is one of the flavonoids with anticancer activity, but its poor water solubility limits its use clinically. In this work, we used monomethoxy poly(ethylene glycol)-poly(e-caprolactone) (MPEG-PCL) micelles to encapsulate Lu by a self-assembly method, creating a water-soluble Lu/MPEG-PCL micelle. These micelles had a mean particle size of 38.6 ± 0.6 nm (polydispersity index = 0.16 ± 0.02), encapsulation efficiency of 98.32% ± 1.12%, and drug loading of 3.93% ± 0.25%. Lu/MPEG-PCL micelles could slowly release Lu in vitro. Encapsulation of Lu in MPEG-PCL micelles improved the half-life (t½; 152.25 ± 49.92 versus [vs] 7.16 ± 1.23 minutes, P = 0.007), area under the curve (0-t) (2914.05 ± 445.17 vs 502.65 ± 140.12 mg/L/minute, P = 0.001), area under the curve (0–∞) (2989.03 ± 433.22 vs 503.81 ± 141.41 mg/L/minute, P = 0.001), and peak concentration (92.70 ± 11.61 vs 38.98 ± 7.73 mg/L, P = 0.003) of Lu when the drug was intravenously administered at a dose of 30 mg/kg in rats. Also, Lu/MPEG-PCL micelles maintained the cytotoxicity of Lu on 4T1 breast cancer cells (IC50 = 6.4 ± 2.30 μg/mL) and C-26 colon carcinoma cells (IC50 = 12.62 ± 2.17 μg/mL) in vitro. These data suggested that encapsulation of Lu into MPEG-PCL micelles created an aqueous formulation of Lu with potential anticancer effect. PMID:23990719

Efficiencies of Dye-Sensitized Solar Cells using Ferritin-Encapsulated Quantum Dots with Various Staining Methods

NASA Astrophysics Data System (ADS)

Perez, Luis

Dye-sensitized solar cells (DSSC) have the potential to replace traditional and cost-inefficient crystalline silicon or ruthenium solar cells. This can only be accomplished by optimizing DSSC's energy efficiency. One of the major components in a dye-sensitized solar cell is the porous layer of titanium dioxide. This layer is coated with a molecular dye that absorbs sunlight. The research conducted for this paper focuses on the different methods used to dye the porous TiO2 layer with ferritin-encapsulated quantum dots. Multiple anodes were dyed using a method known as SILAR which involves deposition through alternate immersion in two different solutions. The efficiencies of DSSCs with ferritin-encapsulated lead sulfide dye deposited using SILAR were subsequently compared against the efficiencies produced by cells using the traditional immersion method. It was concluded that both methods resulted in similar efficiencies (? .074%) however, the SILAR method dyed the TiO2 coating significantly faster than the immersion method. On a related note, our experiments concluded that conducting 2 SILAR cycles yields the highest possible efficiency for this particular binding method. National Science Foundation.

Neuroprotective effect of curcumin-loaded lactoferrin nano particles against rotenone induced neurotoxicity.

PubMed

Bollimpelli, V Satish; Kumar, Prashant; Kumari, Sonali; Kondapi, Anand K

2016-05-01

Curcumin is known to have neuroprotective role and possess antioxidant, anti-inflammatory activities. Rotenone, a flavonoid induced neurotoxicity in dopaminergic cells is being widely studied in Parkinson's Disease (PD) research. In the present study, curcumin loaded lactoferrin nano particles prepared by sol-oil chemistry were used to protect dopaminergic cell line SK-N-SH against rotenone induced neurotoxicity. These curcumin loaded nano particles were of 43-60 nm diameter size and around 100 nm hydrodynamic size as assessed by transmission electron microscopy, atomic force microscopy and dynamic light scattering analysis respectively. The encapsulation efficiency was 61.3% ± 2.4%. Cellular uptake of curcumin through these nano particles was confirmed by confocal imaging and spectrofluorimetric analysis. The curcumin loaded lactoferrin nanoparticles showed greater intracellular drug uptake, sustained retention and greater neuroprotection than soluble counterpart. Neuroprotective activity was characterized through viability assays and by estimating ROS levels. Furthermore rotenone induced PD like features were characterized by decrease in tyrosine hydroxylase expression and increase in α-synuclein expression. Taken together curcumin loaded lactoferrin nanoparticles could be a promising drug delivery strategy against neurotoxicity in dopaminergic neurons. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microencapsulation of Garcinia fruit extract by spray drying and its effect on bread quality.

PubMed

Ezhilarasi, Perumal Natarajan; Indrani, Dasappa; Jena, Bhabani Sankar; Anandharamakrishnan, Chinnaswamy

2014-04-01

(-)-Hydroxycitric acid (HCA) is the major acid present in the fruit rinds of certain species of Garcinia. HCA has been reported to have several health benefits. As HCA is highly hygroscopic in nature and thermally sensitive, it is difficult to incorporate in foodstuffs. Hence, Garcinia cowa fruit extract was microencapsulated using three different wall materials such as whey protein isolate (WPI), maltodextrin (MD) and a combination of whey protein isolate and maltodextrin (WPI + MD) by spray drying. Further, these microencapsulated powders were evaluated for their impact on bread quality and HCA retention. Maltodextrin (MD) encapsulates had higher free (86%) and net HCA (90%) recovery. Microencapsulates incorporated breads had enhanced qualitative characteristics and higher HCA content than water extract incorporated bread due to efficient encapsulation during bread baking. Comparatively, bread with MD encapsulates showed softer crumb texture, desirable sensory attributes with considerable volume and higher HCA content. The higher HCA contents of encapsulate incorporated breads were sufficient to claim for functionality of HCA in bread. Comparatively, MD had efficiently encapsulated Garcinia fruit extract during spray drying and bread baking. Spray drying proved to be an excellent encapsulation technique for incorporation into the food system. © 2013 Society of Chemical Industry.

Impact of culture conditions on β-carotene encapsulation using Yarrowia lipolytica cells

NASA Astrophysics Data System (ADS)

Dang, Tran Hai; Minh, Ho Thi Thu; Van Nhi, Tran Nguyen; Ngoc, Ta Thi Minh

2017-09-01

Yeast cell was reported as an effective natural preformed material for use in encapsulation of hydrophobic compounds. The encapsulation process was normally considered as passive transfer through cellular wall and cellular membrane. Beside solubility of hydrophobic compound in phospholipid membrane or plasmolysis, membrane characteristics of yeast cell which are differed between strains and influenced by culture conditions are main factors involving the accumulation of hydrophobic compound into yeast cell. In this study, the oleaginous yeast Yarrowia lipolytica was used as micro-container shell to encapsulate a high hydrophobic compound - β-carotene. Yeast cell was cultured under different conditions and wet yeast biomass was incubated with β-carotene which was dissolved in soybean oil overnight. β-carotene accumulation was then extracted and evaluated by UV-VIS spectrometry. Optimization of culture condition was investigated using the Box-Behnken model. β-carotene encapsulation efficiency in Y. lipolytica was showed to be affected by both pH of medium and agitation conditions. The highest β-carotene encapsulation efficiency was optimized at 42.8 μg/g with Y. lipolytica cultured at pH 4.5, medium volume equal to 115 ml and agitation speed at 211 rpm.

Investigation on Physicochemical Characteristics of a Nanoliposome-Based System for Dual Drug Delivery

NASA Astrophysics Data System (ADS)

Nam, Jae Hyun; Kim, So-Yeon; Seong, Hasoo

2018-04-01

Synergistic effects of multiple drugs with different modes of action are utilized for combinatorial chemotherapy of intractable cancers. Translation of in vitro synergistic effects into the clinic can be realized using an efficient delivery system of the drugs. Despite a few studies on nano-sized liposomes containing erlotinib (ERL) and doxorubicin (DOX) in a single liposome vesicle, reliable and reproducible preparation methods as well as physicochemical characteristics of a non-PEGylated nanoliposome co-encapsulated with ERL and DOX have not been yet elucidated. In this study, ERL-encapsulated nanoliposomes were prepared using the lipid film-hydration method. By ultrasonication using a probe sonicator, the liposome diameter was reduced to less than 200 nm. DOX was loaded into the ERL-encapsulated nanoliposomes using ammonium sulfate (AS)-gradient or pH-gradient method. Effects of DOX-loading conditions on encapsulation efficiency (EE) of the DOX were investigated to determine an efficient drug-loading method. In the EE of DOX, AS-gradient method was more effective than pH gradient. The dual drug-encapsulated nanoliposomes had more than 90% EE of DOX and 30% EE of ERL, respectively. Transmission electron microscopy and selected area electron diffraction analyses of the dual drug-encapsulated nanoliposomes verified the highly oriented DOX-sulfate crystals inside the liposome as well as the less oriented small crystals of ERL in the outermost region of the nanoliposome. The nanoliposomes were stable at different temperatures without an increase of the nanoliposome diameter. The dual drug-encapsulated nanoliposomes showed a time-differential release of ERL and DOX, implying proper sequential releases for their synergism. The preparation methods and the physicochemical characteristics of the dual drug delivery system contribute to the development of the optimal process and more advanced systems for translational researches.

Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

NASA Astrophysics Data System (ADS)

Li, Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

2009-02-01

Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

Microencapsulation by spray drying of lemon essential oil: Evaluation of mixtures of mesquite gum-nopal mucilage as new wall materials.

PubMed

Cortés-Camargo, Stefani; Cruz-Olivares, Julian; Barragán-Huerta, Blanca E; Dublán-García, Octavio; Román-Guerrero, Angélica; Pérez-Alonso, César

2017-06-01

Mesquite gum (MG) and nopal mucilage (NM) mixtures were used for microencapsulation of lemon essential oil (LEO) by spray drying. Emulsions of MG, NM and MG-NM mixtures (25-75, 50-50, 75-25) were evaluated according to the droplet size (1.49-9.16 μm), viscosity and zeta potential (-16.07 to -20.13 mV), and microcapsules were characterised in particle size (11.9-44.4 μm), morphology, volatile oil retention (VOR) (45.9-74.4%), encapsulation efficiency (EE) (70.9-90.6%), oxidative stability and thermal analysis. The higher concentration of MG led to smaller droplet sizes and lower viscosity in the emulsions, and smaller particle sizes with the highest VOR in microcapsules. The higher concentration of NM induced to higher viscosity in the emulsions, and larger particle sizes with the highest values of EE and oxidative stability in microcapsules. This work shows evidence that MG-NM mixtures can have synergic effect in desirable characteristics such as retention and shelf life extension of LEO in microcapsules.

Structure and stability of human hemoglobin microparticles prepared with a double emulsion technique.

PubMed

Cedrati, N; Bonneaux, F; Labrude, P; Maincent, P

1997-09-01

Hemoglobin solutions can be used as blood substitutes but they present some disadvantages often due to their rapid removal from the bloodstream after injection. A possible way of overcoming this problem is to trap hemoglobin inside particles. This study deals with the preparation, structure and stability of poly(lactic acid) and ethylcellulose microparticles containing human hemoglobin obtained with a double emulsion technique. We investigated the manufacturing process of these particles in order to increase the encapsulation ratio of hemoglobin. For this purpose, some parameters involved in the procedure were optimized, such as hemoglobin concentration and duration of stirring: hemoglobin loading increases with its concentration in the preparation and well-defined stirring time avoids a leakage of hemoglobin. Hemoglobin concentration, surfactant concentration i.e. poly(vinylic alcohol), amounts of polymer and solvent (methylene chloride), duration and speed of stirring. The microparticles were prepared with satisfactory yields (60 to 73%). They were spherical and their mean size was lower than 200 microns. The functional properties of entrapped hemoglobin were studied. The encapsulation did not alter hemoglobin and the oxygen affinity of the hemoglobin remained unmodified (P50 about 13.9 mm Hg in a Bis-Tris buffer pH 7.4 at 37 degrees C). Moreover, only low levels of methemoglobin could be detected (less than 3%). Besides, about 90% of encapsulated hemoglobin could be released from microparticles, with a speed related to the internal structure of the particles. The prepared microparticles were stored during one month at +4 degrees C. No degradation of the particle structure occurred and the functional properties of hemoglobin were preserved. These particles could provide a potential source of oxygen in the field of biotechnologies but any application for a transfusional purpose would first require a drastic reduction in particle size.

Microencapsulation of Nigella sativa oleoresin by spray drying for food and nutraceutical applications.

PubMed

Edris, Amr E; Kalemba, Danuta; Adamiec, Janusz; Piątkowski, Marcin

2016-08-01

Oleoresin of Nigella sativa L. (Black cumin) was obtained from the seeds using hexane extraction at room temperature. The oleoresin was emulsified in an aqueous solution containing gum Arabic/maltodextrin (1:1 w/w) and then encapsulated in powder form by spray drying. The characteristics of the obtained powder including moisture content, bulk density, wettability, morphology, encapsulation efficiency were evaluated. The effect of the spray drying on the chemical composition of the volatile oil fraction of N. sativa oleoresin was also evaluated using gas chromatographic-mass spectroscopic analysis. Results indicated that the encapsulation efficiency of the whole oleoresin in the powder can range from 84.2±1.5% to 96.2±0.2% depending on the conditions of extracting the surface oil from the powder. On the other hand the encapsulation efficiency of the volatile oil fraction was 86.2% ±4.7. The formulated N. sativa L. oleoresin powder can be used in the fortification of processed food and nutraceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Formulation, characterization and evaluation of cyclodextrin-complexed bendamustine-encapsulated PLGA nanospheres for sustained delivery in cancer treatment.

PubMed

Gidwani, Bina; Vyas, Amber

2016-03-01

PLGA nanospheres are considered to be promising drug carrier in the treatment of cancer. Inclusion complex of bendamustine (BM) with epichlorohydrin beta cyclodextrin polymer was prepared by freeze-drying method. Phase solubility study revealed formation of AL type complex with stability constant (Ks = 645 M(-1)). This inclusion complex was encapsulated into PLGA nanospheres using solid-in-oil-in-water (S/O/W) technique. The particle size and zeta potential of PLGA nanospheres loaded with cyclodextrin-complexed BM were about 151.4 ± 2.53 nm and - 31.9 ± (-3.08) mV. In-vitro release study represented biphasic release pattern with 20% burst effect and sustained slow release. DSC studies indicated that inclusion complex incorporated in PLGA nanospheres was not in a crystalline state but existed in an amorphous or molecular state. The cytotoxicity experiment was studied in Z-138 cells and IC50 value was found to be 4.3 ± 0.11 µM. Cell viability studies revealed that the PLGA nanospheres loaded with complex exerts a more pronounced effect on the cancer cells as compared to the free drug. In conclusion, PLGA nanospheres loaded with inclusion complex of BM led to sustained drug delivery. The nanospheres were stable after 3 months of storage conditions with slight change in their particle size, zeta potential and entrapment efficiency.

Development and Characterization of Lecithin-based Self-assembling Mixed Polymeric Micellar (saMPMs) Drug Delivery Systems for Curcumin.

PubMed

Chen, Ling-Chun; Chen, Yin-Chen; Su, Chia-Yu; Wong, Wan-Ping; Sheu, Ming-Thau; Ho, Hsiu-O

2016-11-16

Self-assembling mixed polymeric micelles (saMPMs) were developed for overcoming major obstacles of poor bioavailability (BA) associated with curcumin delivery. Lecithin added was functioned to enlarge the hydrophobic core of MPMs providing greater solubilization capacity. Amphiphilic polymers (sodium deoxycholate [NaDOC], TPGS, CREMOPHOR, or a PLURONIC series) were examined for potentially self-assembling to form MPMs (saMPMs) with the addition of lecithin. Particle size, size distribution, encapsulation efficacy (E.E.), and drug loading (D.L.) of the mixed micelles were optimally studied for their influences on the physical stability and release of encapsulated drugs. Overall, curcumin:lecithin:NaDOC and curcumin:lecithin:PLURONIC P123 in ratios of 2:1:5 and 5:2:20, respectively, were optimally obtained with a particle size of < 200 nm, an E.E. of >80%, and a D.L. of >10%. The formulated system efficiently stabilized curcumin in phosphate-buffered saline (PBS) at room temperature or 4 °C and in fetal bovine serum or PBS at 37 °C and delayed the in vitro curcumin release. In vivo results further demonstrated that the slow release of curcumin from micelles and prolonged duration increased the curcumin BA followed oral and intravenous administrations in rats. Thus, lecithin-based saMPMs represent an effective curcumin delivery system, and enhancing BA of curcumin can enable its wide applications for treating human disorders.

Development and Characterization of Lecithin-based Self-assembling Mixed Polymeric Micellar (saMPMs) Drug Delivery Systems for Curcumin

PubMed Central

Chen, Ling-Chun; Chen, Yin-Chen; Su, Chia-Yu; Wong, Wan-Ping; Sheu, Ming-Thau; Ho, Hsiu-O

2016-01-01

Self-assembling mixed polymeric micelles (saMPMs) were developed for overcoming major obstacles of poor bioavailability (BA) associated with curcumin delivery. Lecithin added was functioned to enlarge the hydrophobic core of MPMs providing greater solubilization capacity. Amphiphilic polymers (sodium deoxycholate [NaDOC], TPGS, CREMOPHOR, or a PLURONIC series) were examined for potentially self-assembling to form MPMs (saMPMs) with the addition of lecithin. Particle size, size distribution, encapsulation efficacy (E.E.), and drug loading (D.L.) of the mixed micelles were optimally studied for their influences on the physical stability and release of encapsulated drugs. Overall, curcumin:lecithin:NaDOC and curcumin:lecithin:PLURONIC P123 in ratios of 2:1:5 and 5:2:20, respectively, were optimally obtained with a particle size of < 200 nm, an E.E. of >80%, and a D.L. of >10%. The formulated system efficiently stabilized curcumin in phosphate-buffered saline (PBS) at room temperature or 4 °C and in fetal bovine serum or PBS at 37 °C and delayed the in vitro curcumin release. In vivo results further demonstrated that the slow release of curcumin from micelles and prolonged duration increased the curcumin BA followed oral and intravenous administrations in rats. Thus, lecithin-based saMPMs represent an effective curcumin delivery system, and enhancing BA of curcumin can enable its wide applications for treating human disorders. PMID:27848996

Development and Characterization of Lecithin-based Self-assembling Mixed Polymeric Micellar (saMPMs) Drug Delivery Systems for Curcumin

NASA Astrophysics Data System (ADS)

Chen, Ling-Chun; Chen, Yin-Chen; Su, Chia-Yu; Wong, Wan-Ping; Sheu, Ming-Thau; Ho, Hsiu-O.

2016-11-01

Self-assembling mixed polymeric micelles (saMPMs) were developed for overcoming major obstacles of poor bioavailability (BA) associated with curcumin delivery. Lecithin added was functioned to enlarge the hydrophobic core of MPMs providing greater solubilization capacity. Amphiphilic polymers (sodium deoxycholate [NaDOC], TPGS, CREMOPHOR, or a PLURONIC series) were examined for potentially self-assembling to form MPMs (saMPMs) with the addition of lecithin. Particle size, size distribution, encapsulation efficacy (E.E.), and drug loading (D.L.) of the mixed micelles were optimally studied for their influences on the physical stability and release of encapsulated drugs. Overall, curcumin:lecithin:NaDOC and curcumin:lecithin:PLURONIC P123 in ratios of 2:1:5 and 5:2:20, respectively, were optimally obtained with a particle size of < 200 nm, an E.E. of >80%, and a D.L. of >10%. The formulated system efficiently stabilized curcumin in phosphate-buffered saline (PBS) at room temperature or 4 °C and in fetal bovine serum or PBS at 37 °C and delayed the in vitro curcumin release. In vivo results further demonstrated that the slow release of curcumin from micelles and prolonged duration increased the curcumin BA followed oral and intravenous administrations in rats. Thus, lecithin-based saMPMs represent an effective curcumin delivery system, and enhancing BA of curcumin can enable its wide applications for treating human disorders.

Chitosan/lecithin liposomal nanovesicles as an oral insulin delivery system.

PubMed

Al-Remawi, Mayyas; Elsayed, Amani; Maghrabi, Ibrahim; Hamaidi, Mohammad; Jaber, Nisrein

2017-05-01

In the present work, insulin-chitosan polyelectrolyte complexes associated to lecithin liposomes were investigated as a new carrier for oral delivery of insulin. The preparation was characterized in terms of particle size, zeta potential and encapsulation efficiency. Surface tension measurements revealed that insulin-chitosan polyelectrolyte complexes have some degree of hydrophobicity and should be added to lecithin liposomal dispersion and not the vice versa to prevent their adsorption on the surface. Stability of insulin was enhanced when it was associated to liposomes. Significant reduction of blood glucose levels was noticed after oral administration of liposomal preparation to streptozotocin diabetic rats compared to control. The hypoglycemic activity was more prolonged compared to subcutaneously administered insulin.

Biomimetic design in microparticulate vaccines.

PubMed

Keegan, Mark E; Whittum-Hudson, Judith A; Mark Saltzman, W

2003-11-01

Current efforts to improve the effectiveness of microparticle vaccines include incorporating biomimetic features into the particles. Many pathogens use surface molecules to target specific cell types in the gut for host invasion. This observation has inspired efforts to chemically conjugate cell-type targeting ligands to the surfaces of microparticles in order to increase the efficiency of uptake, and therefore the effectiveness, of orally administered microparticles. Bio-mimicry is not limited to the exterior surface of the microparticles. Anti-idiotypic antibodies, cytokines or other biological modifiers can be encapsulated for delivery to sites of interest as vaccines or other therapeutics. Direct mucosal delivery of microparticle vaccines or immunomodulatory agents may profoundly enhance mucosal and systemic immune responses compared to other delivery routes.

Preparation and characterisation of alendronate-loaded chitosan microparticles obtained through the spray drying technique.

PubMed

Ochiuz, Lacramioara; Peris, José-Esteban

2009-03-01

Microparticles of chitosan (CHT) containing alendronate sodium (AL) were prepared in four drug:polymer ratios (1:1, 1:2, 1:4, 1:6) using the spray drying technique. The efficiency of the method was evaluated by determining production yield (about 70 %) and microencapsulation efficiency, which was almost 100 % in the case of all four of the formulations studied. Particles had a mean size of between 3.6 and 4.6 microm, and a near-spherical shape. The formulations with the highest content of AL (drug:polymer ratio 1:1 and 1:2) showed an asymmetrical distribution of particles, which were larger in size, and had a higher proportion of irregular particles than the other formulations. FT-IR analysis revealed an ionic interaction between AL and CHT. Differential scanning calorimetry and thermogravimetric analysis confirmed the microencapsulation of AL and the increased thermal stability of encapsulated AL. The dissolution profiles of AL from CHT microspheres, at pH values of 1.2 and 6.8, showed a delayed release of AL from microspheres, and the dissolution rate was dependent on the pH and the drug:polymer ratio. It can be concluded that spray drying is a suitable technique for preparing AL-loaded CHT microspheres, and that the drug:polymer ratio can be used to control the rate of AL release from microspheres.

Wheat germ agglutinin-conjugated chitosan-Ca-alginate microparticles for local colon delivery of 5-FU: development and in vitro characterization.

PubMed

Glavas Dodov, M; Calis, S; Crcarevska, M S; Geskovski, N; Petrovska, V; Goracinova, K

2009-11-03

The aim of this work was to prepare lectin-conjugated chitosan-Ca-alginate microparticles (MPs) loaded with acid-resistant particles of 5-fluorouracil (5-FU) for efficient local treatment of colon cancer. MPs were prepared by a novel one-step spray-drying technique and after wheat germ agglutinin (WGA) conjugation, they were characterized for size, swelling behavior, surface charge, entrapment efficiency and in vitro drug release. Prepared particles were spherical, with 6.73 microg/mg of WGA conjugated onto their surface. The size and zeta potential increased after conjugation, from 6.6 to 14.7 microm and from 9.6 to 15.3 mV, while drug encapsulation was 75.6 and 72.8%, respectively after conjugation. The swelling behavior of beads was mainly determined by properties of the cross-linked chitosan-alginate network. In vitro drug release studies carried out in simulated in vivo conditions with respect to pH, confirmed the potential of the particles to release the drug in a controlled manner. Also, the drug release was not significantly affected by WGA conjugation. The retention of biorecognitive activity of WGA after covalent coupling to MPs was confirmed by haemagglutination test. Functionalized MPs showed excessive mucoadhesiveness in vitro, due to the positive surface charge, pH-dependent swelling of the matrix and lectin-sugar recognition.

Micrometer-sized iron oxide particle labeling of mesenchymal stem cells for magnetic resonance imaging-based monitoring of cartilage tissue engineering.

PubMed

Saldanha, Karl J; Doan, Ryan P; Ainslie, Kristy M; Desai, Tejal A; Majumdar, Sharmila

2011-01-01

To examine mesenchymal stem cell (MSC) labeling with micrometer-sized iron oxide particles (MPIOs) for magnetic resonance imaging (MRI)-based tracking and its application to monitoring articular cartilage regeneration. Rabbit MSCs were labeled using commercial MPIOs. In vitro MRI was performed with gradient echo (GRE) and spin echo (SE) sequences at 3T and quantitatively characterized using line profile and region of interest analysis. Ex vivo MRI of hydrogel-encapsulated labeled MSCs implanted within a bovine knee was performed with spoiled GRE (SPGR) and T(1ρ) sequences. Fluorescence microscopy, labeling efficiency, and chondrogenesis of MPIO-labeled cells were also examined. MPIO labeling results in efficient contrast uptake and signal loss that can be visualized and quantitatively characterized via MRI. SPGR imaging of implanted cells results in ex vivo detection within native tissue, and T(1ρ) imaging is unaffected by the presence of labeled cells immediately following implantation. MPIO labeling does not affect quantitative glycosaminoglycan production during chondrogenesis, but iron aggregation hinders extracellular matrix visualization. This aggregation may result from excess unincorporated particles following labeling and is an issue that necessitates further investigation. This study demonstrates the promise of MPIO labeling for monitoring cartilage regeneration and highlights its potential in the development of cell-based tissue engineering strategies. Published by Elsevier Inc.

Quantum dot-loaded monofunctionalized DNA icosahedra for single-particle tracking of endocytic pathways.

PubMed

Bhatia, Dhiraj; Arumugam, Senthil; Nasilowski, Michel; Joshi, Himanshu; Wunder, Christian; Chambon, Valérie; Prakash, Ved; Grazon, Chloé; Nadal, Brice; Maiti, Prabal K; Johannes, Ludger; Dubertret, Benoit; Krishnan, Yamuna

2016-12-01

Functionalization of quantum dots (QDs) with a single biomolecular tag using traditional approaches in bulk solution has met with limited success. DNA polyhedra consist of an internal void bounded by a well-defined three-dimensional structured surface. The void can house cargo and the surface can be functionalized with stoichiometric and spatial precision. Here, we show that monofunctionalized QDs can be realized by encapsulating QDs inside DNA icosahedra and functionalizing the DNA shell with an endocytic ligand. We deployed the DNA-encapsulated QDs for real-time imaging of three different endocytic ligands-folic acid, galectin-3 (Gal3) and the Shiga toxin B-subunit (STxB). Single-particle tracking of Gal3- or STxB-functionalized QD-loaded DNA icosahedra allows us to monitor compartmental dynamics along endocytic pathways. These DNA-encapsulated QDs, which bear a unique stoichiometry of endocytic ligands, represent a new class of molecular probes for quantitative imaging of endocytic receptor dynamics.

Encapsulation of black carrot juice using spray and freeze drying.

PubMed

Murali, S; Kar, Abhijit; Mohapatra, Debabandya; Kalia, Pritam

2015-12-01

Black carrot juice extracted using pectinase enzyme was encapsulated in three different carrier materials (maltodextrin 20DE, gum arabic and tapioca starch) using spray drying at four inlet temperatures (150, 175, 200 and 225 ℃) and freeze drying at a constant temperature of - 53 ℃ and vacuum of 0.22-0.11 mbar with the constant feed mixture. The products were analyzed for total anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and total colour change. For both the drying methods followed in this study, maltodextrin 20DE as the carrier material has proven to be better in retaining maximum anthocyanin and antioxidant activity compared to gum arabic and tapioca starch. The best spray dried product, was obtained at 150 ℃. The most acceptable was the freeze dried product with maximum anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and colour change. © The Author(s) 2014.

Preparation of inorganic/organic polymer hybrid microcapsules with high encapsulation efficiency by an electrospray technique.

PubMed

Yunoki, Ayumi; Tsuchiya, Eiko; Fukui, Yu; Fujii, Akihiro; Maruyama, Tatsuo

2014-08-13

Microcapsules composed of calcium phosphate and chitosan were prepared in a single step by electrospraying. An aqueous solution containing calcium chloride and chitosan was electrosprayed into a phosphate solution to form a calcium phosphate shell on the sprayed droplets. The resulting microcapsules were 350 μm in average diameter. Investigation using fluorescently labeled chitosan and XRD measurements revealed that the shells of the microcapsules were composed of calcium phosphate (mainly hydroxyapatite) and chitosan. Instead of chitosan, poly(diallyldimethylammonium chloride) and polyethylene glycol were also available for microcapsule production by electrospraying. Variations in the electrospraying conditions resulted in a variety of microcapsule shapes. Various types of substrates were successfully encapsulated in microcapsules with a high encapsulation efficiency (more than 80%). Finally, we succeeded in the encapsulation of living yeast cells in microcapsules, and observed their growth within these microcapsules.

Analysis of Thermal Energy Storage Tank by ANSYS and Comparison with Experimental Results to Improve its Thermal Efficiency

NASA Astrophysics Data System (ADS)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

The discontinuous temperament of the solar power forces to consider about the energy storage. This work is to analyze the tank, amount of energy stored and its storage time. The thermal and flow analysis has been done by ANSYS with different set temperature values. The experimentation is done for various encapsulating materials with different phase change material (PCM). Findings: The results obtained from experimental work are compared with ANSYS output. The competence of the TES is calculated and further improvements are made to enhance its performance. During charging process the temperature distribution from heat transfer fluid (HTF) to PCM is maximum in copper encapsulations followed by aluminium encapsulations and brass encapsulations. The comparison shows only when the electrical power as an input source. The efficient way of captivating solar energy could be a better replacement for electrical input.

Nano-encapsulations liberated from barley protein microparticles for oral delivery of bioactive compounds.

PubMed

Wang, Ruoxi; Tian, Zhigang; Chen, Lingyun

2011-03-15

Novel microparticles (3-5 μm) were created by pre-emulsifying barley proteins with a homogenizer followed a microfluidizer system. These microparticles exhibited a high oil carrying capacity (encapsulation efficiency, 93-97%; loading efficiency, 46-49%). Microparticle degradation and bioactive compound release behaviours were studied in the simulated gastro-intestinal (GI) tract. The data revealed that nano-encapsulations (20-30 nm) were formed as a result of enzymatic degradation of barley protein microparticle bulk matrix in the simulated gastric tract. These nano-encapsulations delivered β-carotene to a simulated human intestinal tract intact, where they were degraded by pancreatic enzymes and steadily released the β-carotene. These uniquely structured microparticles may provide a new strategy for the nutraceutical and pharmaceutical industries to develop targeted delivery systems for lipophilic bioactive compounds. Copyright © 2011 Elsevier B.V. All rights reserved.

A novel system for water soluble protein encapsulation with high efficiency: "micelles enhanced" polyelectrolyte capsules.

PubMed

Li, Xiaodong; Li, Xiaohui; Zhang, Jianxiang; Zhao, Shifang; Shen, Jiacong

2008-06-01

Novel "micelles enhanced" polyelectrolyte (PE) capsules based on functional templates of hybrid calcium carbonate were fabricated. Evidences suggested that the structure of capsule wall was different from that of conventional PE capsules, and the wall permeability of these PE capsules changed significantly. Lysozyme, a positively charged protein in neutral solution, was studied as a model protein to be encapsulated into the "micelles enhanced" PE capsules. Confocal laser scanning microscope was used to observe the entrapping process in real time, while UV-Vis spectroscope and scanning force microscope measurements suggested the high efficiency of encapsulation. In addition, the fluorescence recovery after photobleaching technique was employed to determine the existence form of deposited molecules. Further studies showed even negatively charged water-soluble peptides or proteins can be encapsulated into these hybrid capsules by modulating the pH value in bulk solution under its isoelectronic point as well. Copyright 2007 Wiley Periodicals, Inc.

Encapsulation of basic fibroblast growth factor by polyelectrolyte multilayer microcapsules and its controlled release for enhancing cell proliferation.

PubMed

She, Zhen; Wang, Chunxia; Li, Jun; Sukhorukov, Gleb B; Antipina, Maria N

2012-07-09

Basic fibroblast growth factor (FGF2) is an important protein for cellular activity and highly vulnerable to environmental conditions. FGF2 protected by heparin and bovine serum albumin was loaded into the microcapsules by a coprecipitation-based layer-by-layer encapsulation method. Low cytotoxic and biodegradable polyelectrolytes dextran sulfate and poly-L-arginine were used for capsule shell assembly. The shell thickness-dependent encapsulation efficiency was measured by enzyme-linked immunosorbent assay. A maximum encapsulation efficiency of 42% could be achieved by microcapsules with a shell thickness of 14 layers. The effects of microcapsule concentration and shell thickness on cytotoxicity, FGF2 release kinetics, and L929 cell proliferation were evaluated in vitro. The advantage of using microcapsules as the carrier for FGF2 controlled release for enhancing L929 cell proliferation was analyzed.

Use of Encapsulated Zinc Particles in a Eutectic Chloride Salt to Enhance Thermal Energy Storage Capacity for Concentrated Solar Power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cingarapu, Sreeram; Singh, Dileep; Timofeeva, Elena V.

2015-08-01

Concentrated Solar Power (CSP) is considered as a viable large-scale renewable energy source to produce electricity. However, current costs to produce electricity from CSP are not cost competitive as compared to the traditional energy generation technologies based on fossil fuels and nuclear. It is envisioned that development of high efficiency and high heat capacity thermal storage fluids will increase system efficiency, reduce structural storage volume, and hence, contribute to reducing costs. Particularly, with respect to CSP, current high temperature energy storage fluids, such as molten salts, are relatively limited in terms of their thermal energy storage capacity and thermal conductivity.more » The current work explores possibility of boosting the thermal storage capacity of molten salts through latent heat of added phase change materials. We studied the advantage Of adding coated Zn micron-sized particles to alkali chloride salt eutectic for enhanced thermal energy storage. Zinc particles (0.6 mu m and 5 mu m) obtained from commercial source were coated with an organo-phosphorus shell to improve chemical stability and to prevent individual particles from coalescing with one another during melt/freeze cycles. Thermal cycling tests (200 melt/freeze cycles) showed that coated Zn particles have good thermal stability and are chemically inert to alkali chloride salt eutectic in both N-2 and in air atmospheres. Elemental mapping of the cross-sectional view of coated Zn particles from the composite after thermal cycles showed no signs of oxidation, agglomeration or other type of particle degradation. The measured enhancement in volumetric thermal storage capacity of the composite with just similar to 10 vol% of coated Zn particles over the base chloride salt eutectic varies from 15% to 34% depending on cycling temperature range (Delta T = 50 degrees C -100 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.« less

Photostability effect of silica nanoparticles encapsulated fluorescence dye

NASA Astrophysics Data System (ADS)

Ahmad, Atiqah; Zakaria, Nor Dyana; Razak, Khairunisak Abdul

2017-12-01

Fluorescence dyes are based on small organic molecules have become of interest in chemical biology and widely used for cell and intracellular imaging. However, fluorescence dyes have limitations such as photo bleaching, poor photochemical stability and has a short Stokes shift. It is less valuable for long-term cell tracking strategies and has very short lifetime. In order to overcome the problems, dye-incorporated nanomaterials become of interest. Nanomaterials encapsulation provides a protection layer around the fluorescence dye which improves the stability of fluorescence dye. In this study, silica nanoparticles encapsulated with 1,1%-dioctadecyl-3,3,3%,3%-tetramethylindocarbocyanine perchlorate (Dil) was successfully synthesised by using micelle entrapment method to investigate the effect of encapsulation of nanoparticles towards the properties of fluorescent dye. The synthesised nanoparticles (SiDil) was characterised by particle size analyser, Transmission Electron Microscopy (TEM), UV-Vis spectrometer and Fluorescent spectrometer. Observation using TEM showed spherical shape of nanoparticles with 53 nm diameter. Monodispersed and well nanoparticles distribution was confirmed by low polydispersity index of 0.063 obtained by particle size analyser. Furthermore, the photoluminescence properties of the SiDil were evaluated and compared with bare Dil dye. Both SiDil and bare Dil was radiated under 200 W of Halogen lamp for 60 minutes and the absorbance intensity was measured using UV-Vis spectrometer. The result showed more stable absorbance intensity for SiDil compared to bare Dil dye, which indicated that Si nanoparticles encapsulation improved the photostability property.

The preparation of Cistanche phenylethanoid glycosides liquid proliposomes: Optimized formulation, characterization and proliposome dripping pills in vitro and in vivo evaluation.

PubMed

Li, Meng; Li, Yunjing; Liu, Weiwei; Li, Rongli; Qin, Cuiying; Liu, Nan; Han, Jing

2016-10-10

Water-soluble Cistanche phenylethanoid glycosides (CPhGs) have poor permeability and low bioavailability. However, liposomes can improve the permeability of such drugs and their poor stability, and proliposomes have been used to overcome these problems. Based on this, Cistanche phenylethanoid glycoside liquid proliposomes (CPhGsP) and dripping(?) pills were prepared and optimized using response surface methodology. The properties of CPhGsP were evaluated in terms of their encapsulation efficiency, particle size, zeta potential, and morphology. The results obtained showed that the optimal formulation was drug/soybean phospholipid/poloxamer-188/sodium deoxycholate/propylene glycol 1:22.38:3.52:0.84:80 (w/w/w/w/v). This resulted in an encapsulation efficiency, particle size, and zeta potential of hydrated proliposomes with phosphate buffer solution (pH7.4) of 51.97%, 671.7nm, and -25.49mV, respectively. Stability testing of CPhGsP and CPhGs ordinary liposomes was carried out for 3months at 4±2°C, 25±2°C, 40±2°C, 75±5% RH. The results obtained showed that the stability of the proliposomes was better than that of ordinary liposomes at the same temperature, while a lower temperature of 4°C is ideal for storage. Cistanche phenylethanoid glycoside liquid proliposomes dripping pills (CPhGsPD) are efficiently released in gastrointestinal solution as shown by in vitro release experiments and the structure of the liposomes does not destroy the proliposome dripping pills by hydration. In vivo experiments showed that the areas under the plasma level-time curves and peak concentrations of CPhGsPD and hydrated proliposomes were higher than those of CPhGs. Moreover, with CPhGsPD, the pharmacokinetic parameters were similar to those with hydrated proliposomes. These results showed that CPhGsPD offer a good way to improve the oral delivery of CPhGs. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and Evaluation of Multiple Nanoemulsions Containing Gadolinium (III) Chelate as a Potential Magnetic Resonance Imaging (MRI) Contrast Agent.

PubMed

Sigward, Estelle; Corvis, Yohann; Doan, Bich-Thuy; Kindsiko, Kadri; Seguin, Johanne; Scherman, Daniel; Brossard, Denis; Mignet, Nathalie; Espeau, Philippe; Crauste-Manciet, Sylvie

2015-09-01

The objective was to develop, characterize and assess the potentiality of W1/O/W2 self-emulsifying multiple nanoemulsions to enhance signal/noise ratio for Magnetic Resonance Imaging (MRI). For this purpose, a new formulation, was designed for encapsulation efficiency and stability. Various methods were used to characterize encapsulation efficiency ,in particular calorimetric methods (Differential Scanning Calorimetry (DSC), thermogravimetry analysis) and ultrafiltration. MRI in vitro relaxivities were assessed on loaded DTPA-Gd multiple nanoemulsions. Characterization of the formulation, in particular of encapsulation efficiency was a challenge due to interactions found with ultrafiltration method. Thanks to the specifically developed DSC protocol, we were able to confirm the formation of multiple nanoemulsions, differentiate loaded from unloaded nanoemulsions and measure the encapsulation efficiency which was found to be quite high with a 68% of drug loaded. Relaxivity studies showed that the self-emulsifying W/O/W nanoemulsions were positive contrast agents, exhibiting higher relaxivities than those of the DTPA-Gd solution taken as a reference. New self-emulsifying multiple nanoemulsions that were able to load satisfactory amounts of contrasting agent were successfully developed as potential MRI contrasting agents. A specific DSC protocol was needed to be developed to characterize these complex systems as it would be useful to develop these self-formation formulations.

Modifying the release of leuprolide from spray dried OED microparticles.

PubMed

Alcock, R; Blair, J A; O'Mahony, D J; Raoof, A; Quirk, A V

2002-08-21

A range of oligosaccharide ester derivatives (OEDs) have been designed as drug delivery matrices for controlled release. The synthetic hormone analogue, leuprolide, was encapsulated within these matrices using hydrophobic ion pairing and solvent spray drying. The particles produced modified the release of leuprolide in vitro (dissolution in phosphate buffered saline) and in vivo (subcutaneous and pulmonary delivery in the rat). Release rate was dependent on drug loading and could be manipulated by choice of OED and by combining different OEDs in different ratios. Leuprolide encapsulated in the OEDs retained biological activity as evidenced by elevation in plasma luteinising hormone levels following subcutaneous injection of leuprolide recovered from OED particles in vitro prior to in vivo administration.