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Sample records for delivery system design

  1. MAST Propellant and Delivery System Design Methods

    NASA Technical Reports Server (NTRS)

    Nadeem, Uzair; Mc Cleskey, Carey M.

    2015-01-01

    A Mars Aerospace Taxi (MAST) concept and propellant storage and delivery case study is undergoing investigation by NASA's Element Design and Architectural Impact (EDAI) design and analysis forum. The MAST lander concept envisions landing with its ascent propellant storage tanks empty and supplying these reusable Mars landers with propellant that is generated and transferred while on the Mars surface. The report provides an overview of the data derived from modeling between different methods of propellant line routing (or "lining") and differentiate the resulting design and operations complexity of fluid and gaseous paths based on a given set of fluid sources and destinations. The EDAI team desires a rough-order-magnitude algorithm for estimating the lining characteristics (i.e., the plumbing mass and complexity) associated different numbers of vehicle propellant sources and destinations. This paper explored the feasibility of preparing a mathematically sound algorithm for this purpose, and offers a method for the EDAI team to implement.

  2. Design of Educational Delivery Systems for Lifelong Learning.

    ERIC Educational Resources Information Center

    Gibson, R. Oliver; Gilbert, Randall L.

    To clarify delivery system concepts, several topics will be addressed: educational needs of lower-income older people, formulation of a design concept, specification of the system's concrete aspects, and research/development implications. As the proportion of persons over age sixty-four grows and sensitivity to unmet lifelong learning needs rises,…

  3. The ILC Beam Delivery System - Conceptual Design and RD Plans

    SciTech Connect

    Seryi, Andrei; /SLAC

    2005-05-27

    The Beam Delivery System of the ILC has many stringent and sometimes conflicting requirements. To produce luminosity, the beams must be focused to nanometer size. To provide acceptable detector backgrounds, particles far from the beam core must be collimated. Unique beam diagnostics and instrumentation are required to monitor parameters of the colliding beams such as the energy spectrum and polarization. The detector and beamline components must be protected against errant beams. After collision, the beams must also be transported to the beam dumps safely and with acceptable losses. An international team is actively working on the design of the ILC Beam Delivery System in close collaboration. Details of the design, recent progress and remaining challenges will be summarized in this paper.

  4. Designing and assessing a sustainable networked delivery (SND) system: hybrid business-to-consumer book delivery case study.

    PubMed

    Kim, Junbeum; Xu, Ming; Kahhat, Ramzy; Allenby, Braden; Williams, Eric

    2009-01-01

    We attempted to design and assess an example of a sustainable networked delivery (SND) system: a hybrid business-to-consumer book delivery system. This system is intended to reduce costs, achieve significant reductions in energy consumption, and reduce environmental emissions of critical local pollutants and greenhouse gases. The energy consumption and concomitant emissions of this delivery system compared with existing alternative delivery systems were estimated. We found that regarding energy consumption, an emerging hybrid delivery system which is a sustainable networked delivery system (SND) would consume 47 and 7 times less than the traditional networked delivery system (TND) and e-commerce networked delivery system (END). Regarding concomitant emissions, in the case of CO2, the SND system produced 32 and 7 times fewer emissions than the TND and END systems. Also the SND system offer meaningful economic benefit such as the costs of delivery and packaging, to the online retailer, grocery, and consumer. Our research results show that the SND system has a lot of possibilities to save local transportation energy consumption and delivery costs, and reduce environmental emissions in delivery system. PMID:19209604

  5. Current pharmaceutical design on adhesive based transdermal drug delivery systems.

    PubMed

    Ghosh, Animesh; Banerjee, Subham; Kaity, Santanu; Wong, Tin W

    2015-01-01

    Drug-in-adhesive transdermal drug delivery matrix exploits intimate contact of the carrier with stratum corneum, the principal skin barrier to drug transport, to deliver the actives across the skin and into the systemic circulation. The main application challenges of drug-in-adhesive matrix lie in the physicochemical properties of skin varying with age, gender, ethnicity, health and environmental condition of patients. This in turn poses difficulty to design a universal formulation to meet the intended adhesiveness, drug release and drug permeation performances. This review focuses on pressure-sensitive adhesives, and their adhesiveness and drug release/permeation modulation mechanisms as a function of adhesive molecular structure and formulation attributes. It discusses approaches to modulate adhesive tackiness, strength, elasticity, hydrophilicity, molecular suspension capability and swelling capacity, which contribute to the net effect of adhesive on skin bonding, drug release and drug permeation. PMID:25925119

  6. Design and optimization of floating drug delivery system of acyclovir.

    PubMed

    Kharia, A A; Hiremath, S N; Singhai, A K; Omray, L K; Jain, S K

    2010-09-01

    The purpose of the present work was to design and optimize floating drug delivery systems of acyclovir using psyllium husk and hydroxypropylmethylcellulose K4M as the polymers and sodium bicarbonate as a gas generating agent. The tablets were prepared by wet granulation method. A 3(2) full factorial design was used for optimization of drug release profile. The amount of psyllium husk (X1) and hydroxypropylmethylcellulose K4M (X2) were selected as independent variables. The times required for 50% (t(50%)) and 70% (t(70%)) drug dissolution were selected as dependent variables. All the designed nine batches of formulations were evaluated for hardness, friability, weight variation, drug content uniformity, swelling index, in vitro buoyancy, and in vitro drug release profile. All formulations had floating lag time below 3 min and constantly floated on dissolution medium for more than 24 h. Validity of the developed polynomial equation was verified by designing two check point formulations (C1 and C2). The closeness of predicted and observed values for t(50%) and t(70%) indicates validity of derived equations for the dependent variables. These studies indicated that the proper balance between psyllium husk and hydroxypropylmethylcellulose K4M can produce a drug dissolution profile similar to the predicted dissolution profile. The optimized formulations followed Higuchi's kinetics while the drug release mechanism was found to be anomalous type, controlled by diffusion through the swollen matrix. PMID:21694992

  7. Systems approaches to design of targeted therapeutic delivery.

    PubMed

    Myerson, Jacob W; Brenner, Jacob S; Greineder, Colin F; Muzykantov, Vladimir R

    2015-01-01

    Targeted drug delivery aims to improve therapeutic effects and enable mechanisms that are not feasible for untargeted agents (e.g., due to impermeable biological barriers). To achieve targeting, a drug or its carrier should possess properties providing specific accumulation from circulation at the desired site. There are several examples of systems-inspired approaches that have been applied to achieve this goal. First, proteomics analysis of plasma membrane fraction of the vascular endothelium has identified a series of target molecules and their ligands (e.g., antibodies) that deliver conjugated cargoes to well-defined vascular cells and subcellular compartments. Second, selection of ligands binding to cells of interest using phage display libraries in vitro and in vivo has provided peptides and polypeptides that bind to normal and pathologically altered cells. Finally, large-scale high-throughput combinatorial synthesis and selection of lipid- and polymer-based nanocarriers varying their chemical components has yielded a series of carriers accumulating in diverse organs and delivering RNA interference agents to diverse cells. Together, these approaches offer a basis for systems-based design and selection of targets, targeting molecules, and targeting vehicles. Current studies focus on expanding the arsenal of these and alternative targeting strategies, devising drug delivery systems capitalizing on these strategies and evaluation of their benefit/risk ratio in adequate animal models of human diseases. These efforts, combined with better understanding of mechanisms and unintended consequences of these targeted interventions, need to be ultimately translated into industrial development and the clinical domain. PMID:25946066

  8. Systems approaches to design of targeted therapeutic delivery

    PubMed Central

    Myerson, Jacob W.; Brenner, Jacob S.; Greineder, Colin F.; Muzykantov, Vladimir R.

    2016-01-01

    Targeted drug delivery aims to improve therapeutic effects and enable mechanisms that are not feasible for untargeted agents (e.g., due to impermeable biological barriers). To achieve targeting, a drug or its carrier should possess properties providing specific accumulation from circulation at the desired site. There are several examples of systems-inspired approaches that have been applied to achieve this goal. First, proteomics analysis of plasma membrane fraction of the vascular endothelium has identified a series of target molecules and their ligands (e.g., antibodies) that deliver conjugated cargoes to well-defined vascular cells and subcellular compartments. Second, selection of ligands binding to cells of interest using phage display libraries in vitro and in vivo has provided peptides and polypeptides that bind to normal and pathologically altered cells. Finally, large-scale high-throughput combinatorial synthesis and selection of lipid- and polymer-based nanocarriers varying their chemical components has yielded a series of carriers accumulating in diverse organs and delivering RNA interference agents to diverse cells. Together, these approaches offer a basis for systems-based design and selection of targets, targeting molecules, and targeting vehicles. Current studies focus on expanding the arsenal of these and alternative targeting strategies, devising drug delivery systems capitalizing on these strategies and evaluation of their benefit/risk ratio in adequate animal models of human diseases. These efforts, combined with better understanding of mechanisms and unintended consequences of these targeted interventions, need to be ultimately translated into industrial development and the clinical domain. PMID:25946066

  9. NimbleTools: A Universally Designed Test Delivery System

    ERIC Educational Resources Information Center

    Russell, Michael; Hoffmann, Thomas; Higgins, Jennifer

    2009-01-01

    Students with disabilities and special needs have faced challenges in accessing educational content, and in taking traditional pen-and-paper tests. How might technology improve the process, while making statewide tests truly accessible to all students? NimbleTools is the first computer-based test delivery system that incorporates principles of…

  10. Unsteady jet in designing innovative drug delivery system

    NASA Astrophysics Data System (ADS)

    Wang, Cong; Mazur, Paul; Cosse, Julia; Rider, Stephanie; Gharib, Morteza

    2014-11-01

    Micro-needle injections, a promising pain-free drug delivery method, is constrained by its limited penetration depth. This deficiency can be overcome by implementing fast unsteady jet that can penetrate sub-dermally. The development of a faster liquid jet would increase the penetration depth and delivery volume of micro-needles. In this preliminary work, the nonlinear transient behavior of an elastic tube balloon in providing fast discharge is analyzed. A physical model that combines the Mooney Rivlin Material model and Young-Lapalce's Law was developed and used to investigate the fast discharging dynamic phenomenon. A proof of concept prototype was constructed to demonstrate the feasibility of a simple thumb-sized delivery system to generate liquid jet with desired speed in the range of 5-10 m/s. This work is supported by ZCUBE Corporation.

  11. Design of a Multiple Drug Delivery System Directed at Periodontitis

    PubMed Central

    Sundararaj, Sharath C.; Thomas, Mark V.; Peyyala, Rebecca; Dziubla, Thomas D.; Puleo, David A.

    2013-01-01

    Periodontal disease is highly prevalent, with 90% of the world population affected by either periodontitis or its preceding condition, gingivitis. These conditions are caused by bacterial biofilms on teeth, which stimulate a chronic inflammatory response that leads to loss of alveolar bone and, ultimately, the tooth. Current treatment methods for periodontitis address specific parts of the disease, with no individual treatment serving as a complete therapy. The present research sought to demonstrate development of a multiple drug delivery system for stepwise treatment of different stages of periodontal disease. More specifically, multilayered films were fabricated from an association polymer comprising cellulose acetate phthalate and Pluronic F-127 to achieve sequential release of drugs. The four types of drugs used were metronidazole, ketoprofen, doxycycline, and simvastatin to eliminate infection, inhibit inflammation, prevent tissue destruction, and aid bone regeneration, respectively. Different erosion times and adjustable sequential release profiles were achieved by modifying the number of layers or by inclusion of a slower-eroding polymer layer. Analysis of antibiotic and anti-inflammatory bioactivity showed that drugs released from the devices retained 100% bioactivity. The multilayered CAPP delivery system offers a versatile approach for releasing different drugs based on the pathogenesis of periodontitis and other conditions. PMID:23948165

  12. Design of a multiple drug delivery system directed at periodontitis.

    PubMed

    Sundararaj, Sharath C; Thomas, Mark V; Peyyala, Rebecca; Dziubla, Thomas D; Puleo, David A

    2013-11-01

    Periodontal disease is highly prevalent, with 90% of the world population affected by either periodontitis or its preceding condition, gingivitis. These conditions are caused by bacterial biofilms on teeth, which stimulate a chronic inflammatory response that leads to loss of alveolar bone and, ultimately, the tooth. Current treatment methods for periodontitis address specific parts of the disease, with no individual treatment serving as a complete therapy. The present research sought to demonstrate development of a multiple drug delivery system for stepwise treatment of different stages of periodontal disease. More specifically, multilayered films were fabricated from an association polymer comprising cellulose acetate phthalate and Pluronic F-127 to achieve sequential release of drugs. The four types of drugs used were metronidazole, ketoprofen, doxycycline, and simvastatin to eliminate infection, inhibit inflammation, prevent tissue destruction, and aid bone regeneration, respectively. Different erosion times and adjustable sequential release profiles were achieved by modifying the number of layers or by inclusion of a slower-eroding polymer layer. Analysis of antibiotic and anti-inflammatory bioactivity showed that drugs released from the devices retained 100% bioactivity. The multilayered CAPP delivery system offers a versatile approach for releasing different drugs based on the pathogenesis of periodontitis and other conditions. PMID:23948165

  13. Toward a Contingency Model for Designing Interorganizational Service Delivery Systems

    ERIC Educational Resources Information Center

    Whetten, David A.

    1977-01-01

    Presents a model for designing interorganizational coordination (IOC) systems, based on the premise that different contexts support varying degrees of interorganizational coordination. Identifies key contextual dimensions that administrators should consider in designing an IOC program and suggests guidelines for selecting the appropriate level of…

  14. Design, fabrication, delivery, operation and maintenance of a geothermal power conversion system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The design, fabrication, delivery, operation and maintenance of an Hydrothermal Power Company 1250 KVA geothermal power conversion system using a helical screw expander as the prime mover is described. Hydrostatic and acceptance testing are discussed.

  15. Key Considerations in Designing Oral Drug Delivery Systems for Dogs.

    PubMed

    Song, Yunmei; Peressin, Karl; Wong, Pooi Yin; Page, Stephen W; Garg, Sanjay

    2016-05-01

    The present review discusses the pharmaceutical impact of the anatomy and physiology of the canine gastrointestinal tract to provide a comprehensive guide to the theories and challenges associated with the development of oral drug delivery systems for dogs. Novel pharmaceutical technologies applied to veterinary drugs are discussed indicating the advantages and benefits for animals. There are currently immense research and development efforts being funneled into novel canine health products. Such products are being used to overcome limitations of drugs that display site-dependent absorption or possess poor biopharmaceutical properties. Techniques that are employed to increase bioavailability of the Biopharmaceutics Classification System class II drugs are discussed in this article. Furthermore, an overview of palatable oral formulations for dog care is provided as an approach to easy administration. In vitro and in vivo evaluation and correlation of oral drug formulations in dogs are also addressed. This article assesses the outlook of canine oral drug development recognizing substantial growth forecasts of the dog care market. PMID:27056627

  16. Designing polymeric microparticulate drug delivery system for hydrophobic drug quercetin

    PubMed Central

    Hazra, Moumita; Dasgupta Mandal, Dalia; Mandal, Tamal; Bhuniya, Saikat; Ghosh, Mallika

    2015-01-01

    The aim of this study was to investigate pharmaceutical potentialities of a polymeric microparticulate drug delivery system for modulating the drug profile of poorly water-soluble quercetin. In this research work two cost effective polymers sodium alginate and chitosan were used for entrapping the model drug quercetin through ionic cross linking method. In vitro drug release, swelling index, drug entrapment efficiency, Fourier Transforms Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Differential Scanning Calorimetric (DSC) studies were also done for physicochemical characterization of the formulations. Swelling index and drug release study were done at a pH of 1.2, 6.8 and 7.4 to evaluate the GI mimetic action which entails that the swelling and release of the all the Formulation1 (F1), Formulation2 (F2) and Formulation3 (F3) at pH 1.2 were minimal confirming the prevention of drug release in the acidic environment of stomach. Comparatively more sustained release was seen from the formulations F2 & F3 at pH 6.8 and pH 7.4 after 7 h of drug release profiling. Drug entrapment efficiency of the formulations shows in F1 (D:C:A = 2:5:30) was approximately 70% whereas the increase in chitosan concentration in F2 (D:C:A = 2:10:30) has shown an entrapment efficiency of 81%. But the comparative further increase of chitosan concentration in F3 (D:C:A = 2:15:30) has shown a entrapment of 80% which is not having any remarkable difference from F2. The FTIR analysis of drug, polymers and the formulations indicated the compatibility of the drug with the polymers. The smoothness of microspheres in F2 & F3 was confirmed by Scanning Electron Microscopy (SEM). However F1 microsphere has shown more irregular shape comparatively. The DSC studies indicated the absence of drug-polymer interaction in the microspheres. Our XRD studies have revealed that when pure drug exhibits crystalline structure with less dissolution profile

  17. Design strategies and applications of circulating cell-mediated drug delivery systems

    PubMed Central

    Kim, Gloria B.; Dong, Cheng; Yang, Jian

    2015-01-01

    Drug delivery systems, particularly nanomaterial-based drug delivery systems, possess a tremendous amount of potential to improve diagnostic and therapeutic effects of drugs. Controlled drug delivery targeted to a specific disease is designed to significantly improve the pharmaceutical effects of drugs and reduce their side effects. Unfortunately, only a few targeted drug delivery systems can achieve high targeting efficiency after intravenous injection, even with the development of numerous surface markers and targeting modalities. Thus, alternative drug and nanomedicine targeting approaches are desired. Circulating cells, such as erythrocytes, leukocytes, and stem cells, present innate disease sensing and homing properties. Hence, using living cells as drug delivery carriers has gained increasing interest in recent years. This review highlights the recent advances in the design of cell-mediated drug delivery systems and targeting mechanisms. The approaches of drug encapsulation/conjugation to cell-carriers, cell-mediated targeting mechanisms, and the methods of controlled drug release are elaborated here. Cell-based “live” targeting and delivery could be used to facilitate a more specific, robust, and smart payload distribution for the next-generation drug delivery systems. PMID:25984572

  18. Development and Application of a Systems Engineering Framework to Support Online Course Design and Delivery

    ERIC Educational Resources Information Center

    Bozkurt, Ipek; Helm, James

    2013-01-01

    This paper develops a systems engineering-based framework to assist in the design of an online engineering course. Specifically, the purpose of the framework is to provide a structured methodology for the design, development and delivery of a fully online course, either brand new or modified from an existing face-to-face course. The main strength…

  19. Needs Assessment and the Design of Service Delivery Systems.

    ERIC Educational Resources Information Center

    Gill, Stephen Joel; Fruehling, James A.

    1979-01-01

    Current demands on college counselors for systematic, accountable designs for student development services has required action without the necessary tools. One of these necessary tools is a needs assessment methodology. A methodology for needs assessment is discussed. An example is described. (Author)

  20. Learning Resources for Community Education: Design Notes on Delivery Systems.

    ERIC Educational Resources Information Center

    Bhola, H. S.

    A comprehensive and adaptable system of organizational arrangements is proposed in this document that will enable educational planners in Latin American countries to develop and deliver learning resources for community education and community action programs. A three-tier system of learning resources centers for community education is described.…

  1. Computational design of nanoparticle drug delivery systems for selective targeting

    NASA Astrophysics Data System (ADS)

    Duncan, Gregg A.; Bevan, Michael A.

    2015-09-01

    Ligand-functionalized nanoparticles capable of selectively binding to diseased versus healthy cell populations are attractive for improved efficacy of nanoparticle-based drug and gene therapies. However, nanoparticles functionalized with high affinity targeting ligands may lead to undesired off-target binding to healthy cells. In this work, Monte Carlo simulations were used to quantitatively determine net surface interactions, binding valency, and selectivity between targeted nanoparticles and cell surfaces. Dissociation constant, KD, and target membrane protein density, ρR, are explored over a range representative of healthy and cancerous cell surfaces. Our findings show highly selective binding to diseased cell surfaces can be achieved with multiple, weaker affinity targeting ligands that can be further optimized by varying the targeting ligand density, ρL. Using the approach developed in this work, nanomedicines can be optimally designed for exclusively targeting diseased cells and tissues.Ligand-functionalized nanoparticles capable of selectively binding to diseased versus healthy cell populations are attractive for improved efficacy of nanoparticle-based drug and gene therapies. However, nanoparticles functionalized with high affinity targeting ligands may lead to undesired off-target binding to healthy cells. In this work, Monte Carlo simulations were used to quantitatively determine net surface interactions, binding valency, and selectivity between targeted nanoparticles and cell surfaces. Dissociation constant, KD, and target membrane protein density, ρR, are explored over a range representative of healthy and cancerous cell surfaces. Our findings show highly selective binding to diseased cell surfaces can be achieved with multiple, weaker affinity targeting ligands that can be further optimized by varying the targeting ligand density, ρL. Using the approach developed in this work, nanomedicines can be optimally designed for exclusively targeting

  2. Conceptual design report for the University of Rochester cryogenic target delivery system

    SciTech Connect

    Fagaly, R.L.; Alexander, N.B.; Bourque, R.F.; Dahms, C.F.; Lindgren, J.R.; Miller, W.J.; Bittner, D.N.; Hendricks, C.D.

    1993-05-01

    The upgrade of the Omega laser at the University of Rochester`s Laboratory for Laser Energetics (UR/LLE) will result in a need for large targets filled with D{sub 2} or Dt and maintained at cryogenic temperatures. This mandates a cryogenic target delivery system capable of filling, layering, characterizing and delivering cryogenic targets to the Omega Upgrade target chamber. The program goal is to design, construct, and test the entire target delivery system by June 1996. When completed (including an operational demonstration), the system will be shipped to Rochester for reassembly and commissioning in time for the Omega Upgrade cryogenic campaign, scheduled to start in 1998. General Atomics has been assigned the task of developing the conceptual design for the cryogenic target delivery system. Design and fabrication activities will be closely coordinated with the University of Rochester, Lawrence Livermore National laboratory (LLNL) and Los Alamos National Laboratory (LANL), drawing upon their knowledge base in fuel layering and cryogenic characterization. The development of a target delivery system for Omega could also benefit experiments at Lawrence Livermore National Laboratory and the other ICF Laboratories in that the same technologies could be applied to NOVA, the National Ignition Facility or the future Laboratory Microfusion Facility.

  3. Conceptual design report for the University of Rochester cryogenic target delivery system

    SciTech Connect

    Fagaly, R.L.; Alexander, N.B.; Bourque, R.F.; Dahms, C.F.; Lindgren, J.R.; Miller, W.J. ); Bittner, D.N.; Hendricks, C.D. )

    1993-05-01

    The upgrade of the Omega laser at the University of Rochester's Laboratory for Laser Energetics (UR/LLE) will result in a need for large targets filled with D[sub 2] or Dt and maintained at cryogenic temperatures. This mandates a cryogenic target delivery system capable of filling, layering, characterizing and delivering cryogenic targets to the Omega Upgrade target chamber. The program goal is to design, construct, and test the entire target delivery system by June 1996. When completed (including an operational demonstration), the system will be shipped to Rochester for reassembly and commissioning in time for the Omega Upgrade cryogenic campaign, scheduled to start in 1998. General Atomics has been assigned the task of developing the conceptual design for the cryogenic target delivery system. Design and fabrication activities will be closely coordinated with the University of Rochester, Lawrence Livermore National laboratory (LLNL) and Los Alamos National Laboratory (LANL), drawing upon their knowledge base in fuel layering and cryogenic characterization. The development of a target delivery system for Omega could also benefit experiments at Lawrence Livermore National Laboratory and the other ICF Laboratories in that the same technologies could be applied to NOVA, the National Ignition Facility or the future Laboratory Microfusion Facility.

  4. Design, Characterization, and Optimization of Controlled Drug Delivery System Containing Antibiotic Drug/s.

    PubMed

    Patel, Apurv; Dodiya, Hitesh; Shelate, Pragna; Shastri, Divyesh; Dave, Divyang

    2016-01-01

    The objective of this work was design, characterization, and optimization of controlled drug delivery system containing antibiotic drug/s. Osmotic drug delivery system was chosen as controlled drug delivery system. The porous osmotic pump tablets were designed using Plackett-Burman and Box-Behnken factorial design to find out the best formulation. For screening of three categories of polymers, six independent variables were chosen for Plackett-Burman design. Osmotic agent sodium chloride and microcrystalline cellulose, pore forming agent sodium lauryl sulphate and sucrose, and coating agent ethyl cellulose and cellulose acetate were chosen as independent variables. Optimization of osmotic tablets was done by Box-Behnken design by selecting three independent variables. Osmotic agent sodium chloride, pore forming agent sodium lauryl sulphate, and coating agent cellulose acetate were chosen as independent variables. The result of Plackett-Burman and Box-Behnken design and ANOVA studies revealed that osmotic agent and pore former had significant effect on the drug release up to 12 hr. The observed independent variables were found to be very close to predicted values of most satisfactory formulation which demonstrates the feasibility of the optimization procedure in successful development of porous osmotic pump tablets containing antibiotic drug/s by using sodium chloride, sodium lauryl sulphate, and cellulose acetate as key excipients. PMID:27610247

  5. Design, Characterization, and Optimization of Controlled Drug Delivery System Containing Antibiotic Drug/s

    PubMed Central

    Shelate, Pragna; Dave, Divyang

    2016-01-01

    The objective of this work was design, characterization, and optimization of controlled drug delivery system containing antibiotic drug/s. Osmotic drug delivery system was chosen as controlled drug delivery system. The porous osmotic pump tablets were designed using Plackett-Burman and Box-Behnken factorial design to find out the best formulation. For screening of three categories of polymers, six independent variables were chosen for Plackett-Burman design. Osmotic agent sodium chloride and microcrystalline cellulose, pore forming agent sodium lauryl sulphate and sucrose, and coating agent ethyl cellulose and cellulose acetate were chosen as independent variables. Optimization of osmotic tablets was done by Box-Behnken design by selecting three independent variables. Osmotic agent sodium chloride, pore forming agent sodium lauryl sulphate, and coating agent cellulose acetate were chosen as independent variables. The result of Plackett-Burman and Box-Behnken design and ANOVA studies revealed that osmotic agent and pore former had significant effect on the drug release up to 12 hr. The observed independent variables were found to be very close to predicted values of most satisfactory formulation which demonstrates the feasibility of the optimization procedure in successful development of porous osmotic pump tablets containing antibiotic drug/s by using sodium chloride, sodium lauryl sulphate, and cellulose acetate as key excipients. PMID:27610247

  6. Systems Analysis and Structural Design of an Unpressurized Cargo Delivery Vehicle

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Cruz, Jonathan N.; Antol, Jeffrey; Sasamoto, Washito A.

    2007-01-01

    The International Space Station will require a continuous supply of replacement parts for ongoing maintenance and repair after the planned retirement of the Space Shuttle in 2010. These parts are existing line-replaceable items collectively called Orbital Replacement Units, and include heavy and oversized items such as Control Moment Gyroscopes and stowed radiator arrays originally intended for delivery aboard the Space Shuttle. Current resupply spacecraft have limited to no capability to deliver these external logistics. In support of NASA's Exploration Systems Architecture Study, a team at Langley Research Center designed an Unpressurized Cargo Delivery Vehicle to deliver bulk cargo to the Space Station. The Unpressurized Cargo Delivery Vehicle was required to deliver at least 13,200 lbs of cargo mounted on at least 18 Flight Releasable Attachment Mechanisms. The Crew Launch Vehicle design recommended in the Exploration Systems Architecture Study would be used to launch one annual resupply flight to the International Space Station. The baseline vehicle design developed here has a cargo capacity of 16,000 lbs mounted on up to 20 Flight Releasable Attachment Mechanisms. Major vehicle components are a 5.5m-diameter cargo module containing two detachable cargo pallets with the payload, a Service Module to provide propulsion and power, and an aerodynamic nose cone. To reduce cost and risk, the Service Module is identical to the one used for the Crew Exploration Vehicle design.

  7. Design and performance of feed delivery systems for simulated radioactive waste slurries

    SciTech Connect

    Perez, J.M. Jr.

    1983-02-01

    Processes for vitrifying simulated high-level radioactive waste have been developed at the Pacific Northwest Laboratory (PNL) over the last several years. Paralleling this effort, several feed systems used to deliver the simulated waste slurry to the melter have been tested. Because there had been little industrial experience in delivering abrasive slurries at feed rates of less than 10 L/min, early experience helped direct the design of more-dependable systems. Also, as feed delivery requirements changed, the feed system was modified to meet these new requirements. The various feed systems discussed in this document are part of this evolutionary process, so they have not been ranked against each other. The four slurry feed systems discussed are: (1) vertical-cantilevered centrifugal pump system; (2) airlift feed systems; (3) pressurized-loop systems; and (4) positive-displacement pump system. 20 figures, 11 tables.

  8. Design of Drug Delivery Methods for the Brain and Central Nervous System

    NASA Astrophysics Data System (ADS)

    Lueshen, Eric

    Due to the impermeability of the blood-brain barrier (BBB) to macromolecules delivered systemically, drug delivery to the brain and central nervous system (CNS) is quite difficult and has become an area of intense research. Techniques such as convection-enhanced intraparenchymal delivery and intrathecal magnetic drug targeting offer a means of circumventing the blood-brain barrier for targeted delivery of therapeutics. This dissertation focuses on three aspects of drug delivery: pharmacokinetics, convection-enhanced delivery, and intrathecal magnetic drug targeting. Classical pharmacokinetics mainly uses black-box curve fitting techniques without biochemical or biological basis. This dissertation advances the state-of-the-art of pharmacokinetics and pharmacodynamics by incorporating first principles and biochemical/biotransport mechanisms in the prediction of drug fate in vivo. A whole body physiologically-based pharmacokinetics (PBPK) modeling framework is engineered which creates multiscale mathematical models for entire organisms composed of organs, tissues, and a detailed vasculature network to predict drug bioaccumulation and to rigorously determine kinetic parameters. These models can be specialized to account for species, weight, gender, age, and pathology. Systematic individual therapy design using the proposed mechanistic PBPK modeling framework is also a possibility. Biochemical, anatomical, and physiological scaling laws are also developed to accurately project drug kinetics in humans from small animal experiments. Our promising results demonstrate that the whole-body mechanistic PBPK modeling approach not only elucidates drug mechanisms from a biochemical standpoint, but offers better scaling precision. Better models can substantially accelerate the introduction of drug leads to clinical trials and eventually to the market by offering more understanding of the drug mechanisms, aiding in therapy design, and serving as an accurate dosing tool. Convection

  9. The design and performance of the exubera pulmonary insulin delivery system.

    PubMed

    Harper, Nancy J; Gray, Steven; De Groot, Jennifer; Parker, Joann M; Sadrzadeh, Negar; Schuler, Carlos; Schumacher, Jacqueline D; Seshadri, Sangita; Smith, Adrian E; Steeno, Gregory S; Stevenson, Cynthia L; Taniere, Romain; Wang, May; Bennett, David B

    2007-06-01

    The Exubera system (Pfizer, New York, NY/Nektar Therapeutics, San Carlos, CA) is an integration of five major new technologies: protein formulation, powder processing, powder filling, drug packaging, and delivery device. The product provides a simple interface, where the patient interacts only with the delivery device and powder packaging. These components were designed together to assure repeatable dosing when used by a wide range of patients under real-world life-style and handling conditions. The device design is purely mechanical, using patient-generated compressed air as the energy source. Upon actuation, a sonic discharge of air through the novel release unit reproducibly extracts, de-agglomerates, and disperses the inhalation powder into a respirable aerosol. A clear holding chamber allows for patient feedback via dose visualization and separates aerosol cloud generation from the inspiratory effort. The Exubera product was tested under a wide range of typical use conditions and potential misuse scenarios and following long-term usage in clinical trials. These comprehensive characterization programs demonstrated robust aerosol and mechanical performance, confirming the design intent of the inhaler. These studies provide assurance of consistent and reliable dose delivery in a real-world use of the product. PMID:17563300

  10. Design of nanoemulsion-based delivery systems of natural antimicrobials: effect of the emulsifier.

    PubMed

    Donsì, Francesco; Annunziata, Marianna; Vincensi, Mariarosaria; Ferrari, Giovanna

    2012-06-30

    This work aims at investigating the effect of the nanoemulsion delivery systems on the antimicrobial activity of different essential oil components. Carvacrol, limonene and cinnamaldehyde were encapsulated in the sunflower oil droplets of nanoemulsions prepared by high pressure homogenization and stabilized by different emulsifiers: (a) lecithin, (b) pea proteins, (c) sugar ester and (d) a combination of Tween 20 and glycerol monooleate. The antimicrobial activity was measured against three different microorganisms, such as Escherichia coli, Lactobacillus delbrueckii and Saccharomyces cerevisiae. The measured antimicrobial activity was significantly affected by the formulation of the nanoemulsion, where the different bioactive compounds were encapsulated. In particular, the effect of the delivery systems on the antimicrobial activity was correlated to the concentration of the essential oil components in the aqueous phase in equilibrium with the nanoemulsion droplets, suggesting that the ability of the active molecules to interact with cell membranes is associated to their dissolution in the aqueous phase. These considerations can lead to a more rational design of the nanoemulsion-based delivery systems for essential oils, based on the opportune choice of the emulsifiers in dependence of the desired function of the antimicrobials within the food system. PMID:21763730

  11. Design and construction of a magnetic resonance compatible multi-injector gas jet delivery system.

    PubMed

    Megias-Alguacil, David; Keller, Thierry; Lutz, Kai; Barlow, Ashley P; Ettlin, Dominik A

    2008-01-01

    We present the design, construction, and performance of a novel multi-injector gas jet delivery capable of operating in a magnetic resonance imaging environment. This apparatus is computer controlled and built with two separate pneumatic circuits enabling gas jet applications at variable sites through four independently activated injectors. Gas jet delivery is fully controllable in terms of pressure, flow rate, gas temperature, application time, and duration of interstimulus interval. We characterized these parameters, considering effects such as pressure drop by flow transport, transient effects, and delays in activation. The system offers new possibilities for use in various biomedical contexts such as, e.g., quantitative sensory testing or dental hypersensitivity assessment. PMID:18248053

  12. Challenges in design and characterization of ligand-targeted drug delivery systems

    PubMed Central

    Muro, Silvia

    2012-01-01

    Targeting of therapeutic agents to molecular markers expressed on the surface of cells requiring clinical intervention holds promise to improve specificity of delivery, enhancing therapeutic effects while decreasing potential damage to healthy tissues. Drug targeting to cellular receptors involved in endocytic transport facilitates intracellular delivery, a requirement for a number of therapeutic goals. However, after several decades of experimental design, there is still considerable controversy on the practical outcome of drug targeting strategies. The plethora of factors contributing to the relative efficacy of targeting makes the success of these approaches hardly predictable. Lack of fully specific targets, along with selection of targets with spatial and temporal expression well aligned to interventional requirements, pose difficulties to this process. Selection of adequate sub-molecular target epitopes determines accessibility for anchoring of drug conjugates and bulkier drug carriers, as well as proper signaling for uptake within the cell. Targeting design must adapt to physiological variables of blood flow, disease status, and tissue architecture by accommodating physicochemical parameters such as carrier composition, functionalization, geometry, and avidity. In many cases, opposite features need to meet a balance, e.g., sustained circulation versus efficient targeting, penetration through tissues versus uptake within cells, internalization within endocytic compartment to avoid efflux pumps versus accessibility to molecular targets within the cytosol, etc. Detailed characterization of these complex physiological factors and design parameters, along with a deep understanding of the mechanisms governing the interaction of targeted drugs and carriers with the biological environment, are necessary steps toward achieving efficient drug targeting systems. PMID:22709588

  13. Design of Drug Delivery Methods for the Brain and Central Nervous System

    NASA Astrophysics Data System (ADS)

    Lueshen, Eric

    Due to the impermeability of the blood-brain barrier (BBB) to macromolecules delivered systemically, drug delivery to the brain and central nervous system (CNS) is quite difficult and has become an area of intense research. Techniques such as convection-enhanced intraparenchymal delivery and intrathecal magnetic drug targeting offer a means of circumventing the blood-brain barrier for targeted delivery of therapeutics. This dissertation focuses on three aspects of drug delivery: pharmacokinetics, convection-enhanced delivery, and intrathecal magnetic drug targeting. Classical pharmacokinetics mainly uses black-box curve fitting techniques without biochemical or biological basis. This dissertation advances the state-of-the-art of pharmacokinetics and pharmacodynamics by incorporating first principles and biochemical/biotransport mechanisms in the prediction of drug fate in vivo. A whole body physiologically-based pharmacokinetics (PBPK) modeling framework is engineered which creates multiscale mathematical models for entire organisms composed of organs, tissues, and a detailed vasculature network to predict drug bioaccumulation and to rigorously determine kinetic parameters. These models can be specialized to account for species, weight, gender, age, and pathology. Systematic individual therapy design using the proposed mechanistic PBPK modeling framework is also a possibility. Biochemical, anatomical, and physiological scaling laws are also developed to accurately project drug kinetics in humans from small animal experiments. Our promising results demonstrate that the whole-body mechanistic PBPK modeling approach not only elucidates drug mechanisms from a biochemical standpoint, but offers better scaling precision. Better models can substantially accelerate the introduction of drug leads to clinical trials and eventually to the market by offering more understanding of the drug mechanisms, aiding in therapy design, and serving as an accurate dosing tool. Convection

  14. Design and evaluation of colon specific drug delivery system containing flurbiprofen microsponges.

    PubMed

    Orlu, Mine; Cevher, Erdal; Araman, Ahmet

    2006-08-01

    The purpose of this study was to design novel colon specific drug delivery system containing flurbiprofen (FLB) microsponges. Microsponges containing FLB and Eudragit RS 100 were prepared by quasi-emulsion solvent diffusion method. Additionally, FLB was entrapped into a commercial Microsponge 5640 system using entrapment method. Afterwards, the effects of drug:polymer ratio, inner phase solvent amount, stirring time and speed and stirrer type on the physical characteristics of microsponges were investigated. The thermal behaviour, surface morphology, particle size and pore structure of microsponges were examined. The colon specific formulations were prepared by compression coating and also pore plugging of microsponges with pectin:hydroxypropylmethyl cellulose (HPMC) mixture followed by tabletting. In vitro dissolution studies were done on all formulations and the results were kinetically and statistically evaluated. The microsponges were spherical in shape, between 30.7 and 94.5microm in diameter and showed high porosity values (61-72%). The pore shapes of microsponges prepared by quasi-emulsion solvent diffusion method and entrapment method were found as spherical and cylindrical holes, respectively. Mechanically strong tablets prepared for colon specific drug delivery were obtained owing to the plastic deformation of sponge-like structure of microsponges. In vitro studies exhibited that compression coated colon specific tablet formulations started to release the drug at the 8th hour corresponding to the proximal colon arrival time due to the addition of enzyme, following a modified release pattern while the drug release from the colon specific formulations prepared by pore plugging the microsponges showed an increase at the 8th hour which was the time point that the enzyme addition made. This study presents a new approach based on microsponges for colon specific drug delivery. PMID:16687222

  15. Nanoparticle Drug Delivery Systems Designed to Improve Cancer Vaccines and Immunotherapy

    PubMed Central

    Fan, Yuchen; Moon, James J.

    2015-01-01

    Recent studies have demonstrated great therapeutic potential of educating and unleashing our own immune system for cancer treatment. However, there are still major challenges in cancer immunotherapy, including poor immunogenicity of cancer vaccines, off-target side effects of immunotherapeutics, as well as suboptimal outcomes of adoptive T cell transfer-based therapies. Nanomaterials with defined physico-biochemical properties are versatile drug delivery platforms that may address these key technical challenges facing cancer vaccines and immunotherapy. Nanoparticle systems have been shown to improve targeted delivery of tumor antigens and therapeutics against immune checkpoint molecules, amplify immune activation via the use of new stimuli-responsive or immunostimulatory materials, and augment the efficacy of adoptive cell therapies. Here, we review the current state-of-the-art in nanoparticle-based strategies designed to potentiate cancer immunotherapies, including cancer vaccines with subunit antigens (e.g., oncoproteins, mutated neo-antigens, DNA and mRNA antigens) and whole-cell tumor antigens, dendritic cell-based vaccines, artificial antigen-presenting cells, and immunotherapeutics based on immunogenic cell death, immune checkpoint blockade, and adoptive T-cell therapy. PMID:26350600

  16. Terplex Gene Delivery System.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16243067

  17. Terplex gene delivery system.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16240997

  18. Design and evaluation of an innovative floating and bioadhesive multiparticulate drug delivery system based on hollow structure.

    PubMed

    Zhang, Chungang; Tang, Jingya; Liu, Dechun; Li, Xuetao; Cheng, Lan; Tang, Xing

    2016-04-30

    In this study a gastric-retentive delivery system was prepared by a novel method which is reported here for the first time. An innovative floating and bioadhesive drug delivery system with a hollow structure was designed and prepared. The floating and bioadhesive drug delivery system was composed of a hollow spherical shell, a waterproof layer (Stearic acid), a drug layer (Ofloxacin), a release retarding film (the novel blended coating materials) and a bioadhesive layer (Carbomer 934P) prepared by using a liquid multi-layering process. A novel blended coating material was designed and investigated to solve the problem of the initial burst release of the formulation and the release mechanism of the novel material was analyzed in this study. The optimized formulation provided the sustained release characteristic and was able to float for 24h. The SEM cross-section images showed that the particulates were hollow with a spherical shell. X-ray images and pharmacokinetic studies (Frel = 124.1 ± 28.9%) in vivo showed that the gastric-retentive delivery system can be retained in the stomach for more than 6h. The floating and bioadhesive particulate drug delivery system based on a hollow structure with a dual function presented here is a viable alternative to other for gastroretentive drug delivery system. PMID:26943975

  19. Self-microemulsifying drug delivery system for improved oral bioavailability of oleanolic acid: design and evaluation

    PubMed Central

    Yang, Rui; Huang, Xin; Dou, Jinfeng; Zhai, Guangxi; Su, Lequn

    2013-01-01

    Oleanolic acid is a poorly water-soluble drug with low oral bioavailability. A self-microemulsifying drug delivery system (SMEDDS) has been developed to enhance the solubility and oral bioavailability of oleanolic acid. The formulation design was optimized by solubility assay, compatibility tests, and pseudoternary phase diagrams. The morphology, droplet size distribution, zeta potential, viscosity, electrical conductivity, and refractive index of a SMEDDS loaded with oleanolic acid were studied in detail. Compared with oleanolic acid solution, the in vitro release of oleanolic acid from SMEDDS showed that the drug could be released in a sustained manner. A highly selective and sensitive high-performance liquid chromatographymass spectrometry method was developed for determination of oleanolic acid in rat plasma. This method was used for a pharmacokinetic study of an oleanolic acid-loaded SMEDDS compared with the conventional tablet in rats. Promisingly, a 5.07-fold increase in oral bioavailability of oleanolic acid was achieved for the SMEDDS compared with the marketed product in tablet form. Our studies illustrate the potential use of a SMEDDS for delivery of oleanolic acid via the oral route. PMID:23966781

  20. 3D printing in pharmaceutics: A new tool for designing customized drug delivery systems.

    PubMed

    Jonathan, Goole; Karim, Amighi

    2016-02-29

    Three-dimensional printing includes a wide variety of manufacturing techniques, which are all based on digitally-controlled depositing of materials (layer-by-layer) to create freeform geometries. Therefore, three-dimensional printing processes are commonly associated with freeform fabrication techniques. For years, these methods were extensively used in the field of biomanufacturing (especially for bone and tissue engineering) to produce sophisticated and tailor-made scaffolds from patient scans. This paper aims to review the processes that can be used in pharmaceutics, including the parameters to be controlled. In practice, it not straightforward for a formulator to be aware of the various technical advances made in this field, which is gaining more and more interest. Thus, a particular aim of this review is to give an overview on the pragmatic tools, which can be used for designing customized drug delivery systems using 3D printing. PMID:26757150

  1. Design and Development of a Novel Dual Gas Delivery System in a Plasma Reactor

    NASA Astrophysics Data System (ADS)

    Gani, Nicolas; Shen, Meihua; Du, Yan; Pau, Wilfred; Holland, John; Panagopoulus, Theodoros; Todorow, Valentin; Leahey, Patrick; Nguyen, Hoan

    2003-10-01

    As the IC technology rapidly approaches sub 0.10um geometry, requirements for features critical dimensions (CD) and profile control in gate etch across the wafer become increasingly stringent. Profile and CD uniformity control are related not only to a uniform distribution of etch species (ionic and neutral species) but also more importantly to a uniform distribution of passivation sources (by-products related). While the etch species distribution across the wafer can be effectively controlled through center to edge plasma source power ratio, the etch-byproducts distribution is governed by gas flow dynamics through the balance of convection flux versus diffusion flux. It is therefore critical to design a gas delivery system in a plasma reactor that can offer the flexibility to control the by-products distribution over a wide process region for various applications. This paper presents the development of the tunable gas nozzle design for a decoupled plasma source reactor. Detailed experimental as well as simulations results will be discussed in order to reach an optimal configuration. The process performance for advanced sub 100nm gate etching application on the system will be also presented.

  2. Novel antigen delivery systems.

    PubMed

    Trovato, Maria; De Berardinis, Piergiuseppe

    2015-08-12

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the "E2 scaffold" of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  3. Design and construction of a DNA origami drug delivery system based on MPT64 antibody aptamer for tuberculosis treatment

    PubMed Central

    Ranjbar, Reza; Hafezi-Moghadam, Mohammad Sadegh

    2016-01-01

    Introduction With all of the developments on infectious diseases, tuberculosis (TB) remains a cause of death among people. One of the most promising assembly techniques in nano-technology is “scaffolded DNA origami” to design and construct a nano-scale drug delivery system. Because of the global health problems of tuberculosis, the development of potent new anti-tuberculosis drug delivery system without cross-resistance with known anti-mycobacterial agents is urgently needed. The aim of this study was to design a nano-scale drug delivery system for TB treatment using the DNA origami method Methods In this study, we presented an experimental research on a DNA drug delivery system for treating Tuberculosis. TEM images were visualized with an FEI Tecnai T12 BioTWIN at 120 kV. The model was designed by caDNAno software and computational prediction of the 3D solution shape and its flexibility was calculated with a CanDo server. Results Synthesizing the product was imaged using transmission electron microscopy after negative-staining by uranyl formate. Conclusion We constructed a multilayer 3D DNA nanostructure system by designing square lattice geometry with the scaffolded-DNA-origami method. With changes in the lock and key sequences, we recommend that this system be used for other infectious diseases to target the pathogenic bacteria. PMID:27053991

  4. Systems and Components Fuel Delivery System, Water Delivery System, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  5. Mucoadhesive drug delivery systems

    PubMed Central

    Shaikh, Rahamatullah; Raj Singh, Thakur Raghu; Garland, Martin James; Woolfson, A David; Donnelly, Ryan F.

    2011-01-01

    Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Over the past few decades, mucosal drug delivery has received a great deal of attention. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal). PMID:21430958

  6. Design challenges in nanoparticle-based platforms: Implications for targeted drug delivery systems

    NASA Astrophysics Data System (ADS)

    Mullen, Douglas Gurnett

    Characterization and control of heterogeneous distributions of nanoparticle-ligand components are major design challenges for nanoparticle-based platforms. This dissertation begins with an examination of poly(amidoamine) (PAMAM) dendrimer-based targeted delivery platform. A folic acid targeted modular platform was developed to target human epithelial cancer cells. Although active targeting was observed in vitro, active targeting was not found in vivo using a mouse tumor model. A major flaw of this platform design was that it did not provide for characterization or control of the component distribution. Motivated by the problems experienced with the modular design, the actual composition of nanoparticle-ligand distributions were examined using a model dendrimer-ligand system. High Pressure Liquid Chromatography (HPLC) resolved the distribution of components in samples with mean ligand/dendrimer ratios ranging from 0.4 to 13. A peak fitting analysis enabled the quantification of the component distribution. Quantified distributions were found to be significantly more heterogeneous than commonly expected and standard analytical parameters, namely the mean ligand/nanoparticle ratio, failed to adequately represent the component heterogeneity. The distribution of components was also found to be sensitive to particle modifications that preceded the ligand conjugation. With the knowledge gained from this detailed distribution analysis, a new platform design was developed to provide a system with dramatically improved control over the number of components and with improved batch reproducibility. Using semi-preparative HPLC, individual dendrimer-ligand components were isolated. The isolated dendrimer with precise numbers of ligands were characterized by NMR and analytical HPLC. In total, nine different dendrimer-ligand components were obtained with degrees of purity ≥80%. This system has the potential to serve as a platform to which a precise number of functional molecules

  7. Drug delivery system design and development for boron neutron capture therapy on cancer treatment.

    PubMed

    Sherlock Huang, Lin-Chiang; Hsieh, Wen-Yuan; Chen, Jiun-Yu; Huang, Su-Chin; Chen, Jen-Kun; Hsu, Ming-Hua

    2014-06-01

    We have already synthesized a boron-containing polymeric micellar drug delivery system for boron neutron capture therapy (BNCT). The synthesized diblock copolymer, boron-terminated copolymers (Bpin-PLA-PEOz), consisted of biodegradable poly(D,l-lactide) (PLA) block and water-soluble polyelectrolyte poly(2-ethyl-2-oxazoline) (PEOz) block, and a cap of pinacol boronate ester (Bpin). In this study, we have demonstrated that synthesized Bpin-PLA-PEOz micelle has great potential to be boron drug delivery system with preliminary evaluation of biocompatibility and boron content. PMID:24447933

  8. Polymers for Drug Delivery Systems

    PubMed Central

    Liechty, William B.; Kryscio, David R.; Slaughter, Brandon V.; Peppas, Nicholas A.

    2012-01-01

    Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. From early beginnings using off-the-shelf materials, the field has grown tremendously, driven in part by the innovations of chemical engineers. Modern advances in drug delivery are now predicated upon the rational design of polymers tailored for specific cargo and engineered to exert distinct biological functions. In this review, we highlight the fundamental drug delivery systems and their mathematical foundations and discuss the physiological barriers to drug delivery. We review the origins and applications of stimuli-responsive polymer systems and polymer therapeutics such as polymer-protein and polymer-drug conjugates. The latest developments in polymers capable of molecular recognition or directing intracellular delivery are surveyed to illustrate areas of research advancing the frontiers of drug delivery. PMID:22432577

  9. Intracochlear Drug Delivery Systems

    PubMed Central

    Borenstein, Jeffrey T.

    2011-01-01

    Introduction Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear, are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. Areas covered in this review Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices, and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development, and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. Expert Opinion Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases. PMID:21615213

  10. Capsaicin-loaded vesicular systems designed for enhancing localized delivery for psoriasis therapy.

    PubMed

    Gupta, Ruchi; Gupta, Madhu; Mangal, Sharad; Agrawal, Udita; Vyas, Suresh Prasad

    2016-05-01

    The aim of the current investigation is to evaluate the potential of capsaicin (CAP)-containing liposomes, niosomes and emulsomes in providing localized and controlled delivery, to improve the topical delivery of drug. CAP-bearing systems were prepared by the film hydration method and compared through various in vitro and in vivo parameters. The TEM photographs suggested that the carrier systems were spherical in shape and nanometric in size range. Skin retention studies of CAP from in vitro and in vivo experiments revealed significantly higher accumulation of drug in the case of the emul-gel formulation. Based on the results, we concluded that the emul-gel may be a potential approach for the topical delivery of CAP, for an effective therapy for psoriasis. PMID:25465045

  11. Role of particle size, shape, and stiffness in design of intravascular drug delivery systems: insights from computations, experiments, and nature.

    PubMed

    Sen Gupta, Anirban

    2016-03-01

    Packaging of drug molecules within microparticles and nanoparticles has become an important strategy in intravascular drug delivery, where the particles are designed to protect the drugs from plasma effects, increase drug residence time in circulation, and often facilitate drug delivery specifically at disease sites. To this end, over the past few decades, interdisciplinary research has focused on developing biocompatible materials for particle fabrication, technologies for particle manufacture, drug formulation within the particles for efficient loading, and controlled release and refinement of particle surface chemistries to render selectivity toward disease site for site-selective action. Majority of the particle systems developed for such purposes are spherical nano and microparticles and they have had low-to-moderate success in clinical translation. To refine the design of delivery systems for enhanced performance, in recent years, researchers have started focusing on the physicomechanical aspects of carrier particles, especially their shape, size, and stiffness, as new design parameters. Recent computational modeling studies, as well as, experimental studies using microfluidic devices are indicating that these design parameters greatly influence the particles' behavior in hemodynamic circulation, as well as cell-particle interactions for targeted payload delivery. Certain cellular components of circulation are also providing interesting natural cues for refining the design of drug carrier systems. Based on such findings, new benefits and challenges are being realized for the next generation of drug carriers. The current article will provide a comprehensive review of these findings and discuss the emerging design paradigm of incorporating physicomechanical components in fabrication of particulate drug delivery systems. WIREs Nanomed Nanobiotechnol 2016, 8:255-270. doi: 10.1002/wnan.1362 For further resources related to this article, please visit the WIREs

  12. An Information Push-Delivery System Design for Personal Information Service on the Internet.

    ERIC Educational Resources Information Center

    Chen, Chen-Tung; Tai, Wei-Shen

    2003-01-01

    Discussion of information overload from the Internet focuses on an information push-delivery system, which applies fuzzy information retrieval and fuzzy similarity measurement to avoid the information overload problem. Describes an empirical investigation conducted with students at Da-Yeh University (Taiwan) that investigated satisfaction with a…

  13. Drug delivery systems.

    PubMed

    Robinson, D H; Mauger, J W

    1991-10-01

    New and emerging drug delivery systems for traditional drugs and the products of biotechnology are discussed, and the role of the pharmacist in ensuring the appropriate use of these systems is outlined. Advantages of advanced drug delivery systems over traditional systems are the ability to deliver a drug more selectively to a specific site; easier, more accurate, less frequent dosing; decreased variability in systemic drug concentrations; absorption that is more consistent with the site and mechanism of action; and reductions in toxic metabolites. Four basic strategies govern the mechanisms of advanced drug delivery: physical, chemical, biological, and mechanical. Oral drug delivery systems use natural and synthetic polymers to deliver the product to a specific region in the gastrointestinal tract in a timely manner that minimizes adverse effects and increases drug efficacy. Innovations in injectable and implantable delivery systems include emulsions, particulate delivery systems, micromolecular products and macromolecular drug adducts, and enzymatic-controlled delivery. Options for noninvasive drug delivery include the transdermal, respiratory, intranasal, ophthalmic, lymphatic, rectal, intravaginal, and intrauterine routes as well as topical application. Rapid growth is projected in the drug delivery systems market worldwide in the next five years. Genetic engineering has mandated the development of new strategies to deliver biotechnologically derived protein and peptide drugs and chemoimmunoconjugates. The role of the pharmacist in the era of advanced drug delivery systems will be broad based, including administering drugs, compounding, calculating dosages based on pharmacokinetic and pharmacodynamic monitoring, counseling, and research. The advent of advanced drug delivery systems offers pharmacists a new opportunity to assume an active role in patient care. PMID:1772110

  14. Emerging hydrogel designs for controlled protein delivery.

    PubMed

    Bae, Ki Hyun; Kurisawa, Motoichi

    2016-08-19

    Hydrogels have evolved into indispensable biomaterials in the fields of drug delivery and regenerative medicine. This minireview aims to highlight the recent advances in the hydrogel design for controlled release of bioactive proteins. The latest developments of enzyme-responsive and externally regulated drug delivery systems are summarized. The design strategies and applications of phase-separated hydrogel systems are also described. We expect that these emerging approaches will enable expanded use of hydrogels in biomedicine and healthcare. PMID:27374633

  15. Design and optimization of self-nanoemulsifying drug delivery systems for improved bioavailability of cyclovirobuxine D

    PubMed Central

    Ke, Zhongcheng; Hou, Xuefeng; Jia, Xiao-bin

    2016-01-01

    Background The main purpose of this research was to design a self-nanoemulsifying drug delivery system (SNEDDS) for improving the bioavailability of cyclovirobuxine D as a poorly water-soluble drug. Materials and methods Solubility trials, emulsifying studies, and pseudo-ternary phase diagrams were used to screen the SNEDDS formulations. The optimized drug-loaded SNEDDS was prepared at a mass ratio of 3:24:38:38 for cyclovirobuxine D, oleic acid, Solutol SH15, and propylene glycol, respectively. The optimized formulation was characterized in terms of physicochemical and pharmacokinetic parameters compared with marketed cyclovirobuxine D tablets. Results The optimized cyclovirobuxine-D-loaded SNEDDS was spontaneously dispersed to form a nanoemulsion with a globule size of 64.80±3.58 nm, which exhibited significant improvement of drug solubility, rapid absorption rate, and enhanced area under the curve, together with increased permeation and decreased efflux. Fortunately, there was a nonsignificant cytotoxic effect toward Caco-2 cells. The relative bioavailability of SNEDDS was 200.22% in comparison with market tablets, in rabbits. Conclusion SNEDDS could be a potential candidate for an oral dosage form of cyclovirobuxine D with improved bioavailability. PMID:27418807

  16. Transmembrane heme delivery systems

    PubMed Central

    Goldman, Barry S.; Beck, David L.; Monika, Elizabeth M.; Kranz, Robert G.

    1998-01-01

    Heme proteins play pivotal roles in a wealth of biological processes. Despite this, the molecular mechanisms by which heme traverses bilayer membranes for use in biosynthetic reactions are unknown. The biosynthesis of c-type cytochromes requires that heme is transported to the bacterial periplasm or mitochondrial intermembrane space where it is covalently ligated to two reduced cysteinyl residues of the apocytochrome. Results herein suggest that a family of integral membrane proteins in prokaryotes, protozoans, and plants act as transmembrane heme delivery systems for the biogenesis of c-type cytochromes. The complete topology of a representative from each of the three subfamilies was experimentally determined. Key histidinyl residues and a conserved tryptophan-rich region (designated the WWD domain) are positioned at the site of cytochrome c assembly for all three subfamilies. These histidinyl residues were shown to be essential for function in one of the subfamilies, an ABC transporter encoded by helABCD. We believe that a directed heme delivery pathway is vital for the synthesis of cytochromes c, whereby heme iron is protected from oxidation via ligation to histidinyl residues within the delivery proteins. PMID:9560218

  17. Optical fiber diffusive tip designs for medical laser-lightguide delivery systems

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis; Pfafrods, Daumants; Stafeckis, Maris

    1994-12-01

    Medical laser radiation delivery instruments with diffusive tips on the distal ends of plastic-clad silica optical fibers have been designed, tested, and manufactured. The instruments are optimized for endoscopic, therapeutic, dermatologic and surgical laser treatment. The diffusive tips provide radial, cylindrical and aside-conical spatial distributions of the output radiation. Optical schemes concerning each type of the tip and the corresponding spatial distribution functions of the output radiation are presented and analyzed. Designs of the lightguide instruments for surgical and dermatological procedures demanding local high-power laser irradiation are also discussed.

  18. Novel antigen delivery systems

    PubMed Central

    Trovato, Maria; Berardinis, Piergiuseppe De

    2015-01-01

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the “E2 scaffold” of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  19. Design and evaluation of oral nanoemulsion drug delivery system of mebudipine.

    PubMed

    Khani, Samira; Keyhanfar, Fariborz; Amani, Amir

    2016-07-01

    A nanoemulsion drug delivery system was developed to increase the oral bioavailability of mebudipine as a calcium channel blocker with very low bioavailability profile. The impact of nano-formulation on the pharmacokinetic parameters of mebudipine in rats was investigated. Nanoemulsion formulations containing ethyl oleate, Tween 80, Span 80, polyethylene glycol 400, ethanol and deionized water were prepared using probe sonicator. The optimum formulation was evaluated for physicochemical properties, such as particle size, morphology and stability. The particle size of optimum formulation was 22.8 ± 4.0 nm. Based on the results of this study, the relative bioavailability of mebudipine nanoemulsion was enhanced by about 2.6-, 2.0- and 1.9-fold, respectively, compared with suspension, ethyl oleate solution and micellar solution. In conclusion, nanoemulsion is an interesting option for the delivery of poorly water soluble molecules, such as mebudipine. PMID:26406153

  20. Design of a platform technology for systemic delivery of siRNA to tumours using rolling circle transcription

    PubMed Central

    Jang, Mihue; Kim, Jong Hwan; Nam, Hae Yun; Kwon, Ick Chan; Ahn, Hyung Jun

    2015-01-01

    For therapeutic applications of siRNA, there are technical challenges with respect to targeted and systemic delivery. We here report a new siRNA carrier, RNAtr NPs, in a way that multiple tandem copies of RNA hairpins as a result of rolling circle transcription (RCT) can be readily adapted in tumour-targeted and systemic siRNA delivery. RNAtr NPs provide a means of condensing large amounts of multimeric RNA transcripts into the compact nanoparticles, especially without the aid of polycationic agents, and thus reduce the risk of immunogenicity and cytotoxicity by avoiding the use of synthetic polycationic reagents. This strategy allows the design of a platform technology for systemic delivery of siRNA to tumour sites, because RCT reaction, which enzymatically generates RNA polymers in multiple copy numbers at low cost, can lead to directly accessible routes to targeted and systemic delivery. Therefore, RNAtr NPs suggest great potentials as the siRNA therapeutics for cancer treatment. PMID:26246279

  1. Conceptual design of a closed loop nutrient solution delivery system for CELSS implementation in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Schwartzkopf, Steven H.; Oleson, Mel W.; Cullingford, Hatice S.

    1990-01-01

    Described here are the results of a study to develop a conceptual design for an experimental closed loop fluid handling system capable of monitoring, controlling, and supplying nutrient solution to higher plants. The Plant Feeder Experiment (PFE) is designed to be flight tested in a microgravity environment. When flown, the PFX will provide information on both the generic problems of microgravity fluid handling and the specific problems associated with the delivery of the nutrient solution in a microgravity environment. The experimental hardware is designed to fit into two middeck lockers on the Space Shuttle, and incorporates several components that have previously been flight tested.

  2. Design, synthesis, and pharmacokinetic evaluation of a chemical delivery system for drug targeting to lung tissue.

    PubMed

    Saah, M; Wu, W M; Eberst, K; Marvanyos, E; Bodor, N

    1996-05-01

    We espouse the application of a novel chemical delivery system (CDS) approach to a delivery mechanism for drug targeting to lung tissue using the 1,2-dithiolane-3-pentyl moiety of lipoic acid as the "targetor moiety". The synthesis and the physicochemical and pharmacokinetic evaluation of a CDS modeling the lipoyl and other ester derivatives of chlorambucil (an antineoplastic agent) and cromolyn (a bischromone used in antiasthma prophylaxis) as compared with their respective parent drugs are described. The chlorambucil CDS was synthesized by esterifying the alcohol derivative of lipoic acid with chlorambucil using dicyclohexylcarbodiimide as the coupling agent. The cromolyn CDS was prepared by a multistep synthetic procedure culminating in the reaction of the alkyl bromide derivative of lipoic acid with the disodium salt of the bischromone compound. All the esters were highly lipophilic unlike the parent compounds. The in-vitro kinetic and in-vivo pharmacokinetic studies showed that the respective CDSs were sufficiently stable in buffer and biological media, hydrolyzed rapidly into the respective active parent drugs, and significantly enhanced delivery and retention of the active compound to lung tissue in comparison with the underivatized parent compounds used in conventional therapy. PMID:8742941

  3. Design and in vitro evaluation of multiparticulate floating drug delivery system of zolpidem tartarate.

    PubMed

    Amrutkar, P P; Chaudhari, P D; Patil, S B

    2012-01-01

    Zolpidem tartarate is a non-benzodiazepine, sedative-hypnotic, which finds its major use in various types of insomnia. The present work relates to development of multiparticulate floating drug delivery system based on gas generation technique to prolong the gastric residence time and to increase the overall bioavailability. Modified release dosage form of zolpidem tartarate adapted to release over a predetermined time period, according to biphasic profile of dissolution, where the first phase is immediate release phase for inducing the sleep and the second phase is modified release phase for maintaining the sleep up to 10 h. The system consists of zolpidem tartarate layered pellets coated with effervescent layer and polymeric membrane. The floating ability and in vitro drug release of the system were dependent on amount of the effervescent agent (sodium bicarbonate) layered onto the drug layered pellets, and coating level of the polymeric membrane (Eudragit(®) NE 30D). The system could float completely within 5 min and maintain the floating over a period of 10 h. The multiparticulate floating delivery system of zolpidem tartarate with rapid floating and modified drug release was obtained. PMID:21974910

  4. Design of a light delivery system for the photodynamic treatment of the Crohn's disease

    NASA Astrophysics Data System (ADS)

    Gabrecht, Tanja; Borle, Francois; van den Bergh, Hubert; Michetti, Pierre; Ortner, Maria-Anna; Wagnières, Georges

    2007-07-01

    Crohn's disease is an inflammatory bowel disease originating from an overwhelming response of the mucosal immune system. Low dose photodynamic therapy (PDT) may modify the mucosal immune response and thus serve as a therapy for Crohn's disease. Most patients with Crohn's disease show inflammatory reactions in the terminal ileum or colon where PDT treatment is feasible by low-invasive endoscopic techniques. However, the tube like geometry of the colon, it's folding, and the presences of multiple foci of Crohn's lesions along the colon require the development of adequate light delivery techniques. We present a prototype light delivery system for endoscopic clinical PDT in patients with Crohn's disease. The system is based on a cylindrical light diffuser inserted into a diffusing balloon catheter. Homogenous irradiation is performed with a 4 W diode laser at 635 nm. Light dosimetry is performed using a calibrated integrating sphere. The system can be used with conventional colonoscopes and colonovideoscopes having a 3.8 mm diameter working channel. The feasibility of PDT in colon with our prototype was demonstrated in first clinical trials.

  5. Peptide and protein delivery using new drug delivery systems.

    PubMed

    Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery. PMID:23662604

  6. Cell-Targeting Cationic Gene Delivery System Based on a Modular Design Rationale.

    PubMed

    Liu, Jia; Xu, Luming; Jin, Yang; Qi, Chao; Li, Qilin; Zhang, Yunti; Jiang, Xulin; Wang, Guobin; Wang, Zheng; Wang, Lin

    2016-06-01

    En route to target cells, a gene carrier faces multiple extra- and intracellular hurdles that would affect delivery efficacy. Although diverse strategies have been proposed to functionalize gene carriers for individually overcoming these barriers, it is challenging to generate a single multifunctional gene carrier capable of surmounting all these barriers. Aiming at this challenge, we have developed a supramolecular modular approach to fabricate a multifunctional cationic gene delivery system. It consists of two prefunctionalized modules: (1) a host module: a polymer (PCD-SS-PDMAEMA) composed of poly(β-cyclodextrin) backbone and disulfide-linked PDMAEMA arms, expectedly acting to compact DNA and release DNA upon cleavage of disulfide linkers in reductive microenvironment; and (2) a guest module: adamantyl and folate terminated PEG (Ad-PEG-FA), expectedly functioning to reduce nonspecific interactions, improve biocompatibility, and provide folate-mediated cellular targeting specificity. Through the host-guest interaction between β-cyclodextrin units of the "host" module and adamantyl groups of the "guest" module, the PCD-SS-PDMAEMA-1 (host) and Ad-PEG-FA (guest) self-assemble forming a supramolecular pseudocopolymer (PCD-SS-PDMAEMA-1/PEG-FA). Our comprehensive analyses demonstrate that the functions preassigned to the two building modules are well realized. The gene carrier effectively compacts DNA into stable nanosized polyplexes resistant to enzymatic digestion, triggers DNA release in reducing environment, possesses significantly improved hemocompatibility, and specifically targets folate-receptor positive cells. Most importantly, endowed with these predesigned functions, the PCD-SS-PDMAEMA-1/PEG-FA supramolecular gene carrier exhibits excellent transfection efficacy for both pDNA and siRNA. Thus, this work represents a proof-of-concept example showing the efficiency and convenience of an adaptable, modular approach for conferring multiple functions to a single

  7. Documenting data delivery: design, deployment, and decision.

    PubMed Central

    Lundy, M. S.; Hammond, W. E.; Lobach, D. F.

    1996-01-01

    Developing and deploying informatics solutions which are useful and acceptable to busy physicians are challenging tasks. We describe the design, deployment, and evaluation process by which the delivery of routine clinical laboratory reports is automated using electronic mail. Data from TMR, an operational computer-based patient record (CPR), are presented to providers using an individualized, modern interface. This system is compared to the existing, paper-based system for delivery of data from the same CPR. Differences between the two systems of data delivery are analyzed, with emphases on 1) electronic documentation of data delivery and receipt, 2) electronic and/or paper documentation of clinical action taken as a result of laboratory reports, 3) timeliness of report availability, 4) costs, 5) workflow compatibility, and 6) physician satisfaction. The new delivery system employs inexpensive, commercially available software applications and entails only trivial changes to the proprietary CPR. Built into the new system are features which allow quantitative measurements of its performance for analysis along with survey-based user satisfaction data. The open systems design is deliberately non-proprietary, inexpensive, and generalizable. Accordingly, it offers practical possibilities for settings in which clinical information systems are just being planned, as well as for those in which such systems are already established. PMID:8947777

  8. Special Delivery Systems. Final Report.

    ERIC Educational Resources Information Center

    Molek, Carol

    The Special Delivery Systems project developed a curriculum for students with learning disabilities (LD) in an adult basic education program. The curriculum was designed to assist and motivate the students in the educational process. Fourteen students with LD were recruited and screened. The curriculum addressed varied learning styles combined…

  9. Design and evaluation of a novel chitosan-based system for colon-specific drug delivery.

    PubMed

    Kavianinia, Iman; Plieger, Paul G; Cave, Nicholas J; Gopakumar, Gayathri; Dunowska, Magdalena; Kandile, Nadia G; Harding, David R K

    2016-04-01

    Tritrichomonas foetus is a flagellated protozoan parasite that colonizes the feline colon causing colitis and chronic foul smelling diarrhoea. Despite the efficacy of Ronidazole in the treatment of T. foetus, Ronidazole has been reported to cause neurotoxicity in some cats due to rapid absorption in the small intestine. A novel amphoteric derivative of chitosan was synthesised and characterized. A combination of time, pH, and an enzyme controlled system was used in a study of a new compression coated tablet for delivery of Ronidazole to the colon. Axial, radial swelling and erosion of selected tablets were carried out in various media. The effect of weight ratio, enzyme and pH on in vitro drug release profile was investigated. The results show that less than 2% of the drug was released in the physiological environment of the stomach and small intestine. PMID:26791585

  10. Design, fabrication, testing, and delivery of a solar energy collector system for residential heating and cooling

    NASA Technical Reports Server (NTRS)

    Holland, T. H.; Borzoni, J. T.

    1976-01-01

    A low cost flat plate solar energy collector was designed for the heating and cooling of residential buildings. The system meets specified performance requirements, at the desired system operating levels, for a useful life of 15 to 20 years, at minimum cost and uses state-of-the-art materials and technology. The rationale for the design method was based on identifying possible material candidates for various collector components and then selecting the components which best meet the solar collector design requirements. The criteria used to eliminate certain materials were: performance and durability test results, cost analysis, and prior solar collector fabrication experience.

  11. Self nanoemulsifying drug delivery system (SNEDDS) of rosuvastatin calcium: design, formulation, bioavailability and pharmacokinetic evaluation.

    PubMed

    Balakumar, Krishnamoorthy; Raghavan, Chellan Vijaya; selvan, Natarajan Tamil; prasad, Ranganathan Hari; Abdu, Siyad

    2013-12-01

    The aim of the present study is to improve solubility and bioavailability of Rosuvastatin calcium using self nanoemulsifying drug delivery system (SNEDDS). Self emulsifying property of various oils including essential oils was evaluated with suitable surfactants and co-surfactants. Ternary phase diagrams were constructed based on Rosuvastatin calcium solubility analysis for optimizing the system. The prepared formulations were evaluated for self emulsifying time, robustness to dilution, droplet size determination and zeta potential analysis. The system was found to be robust in different pH media and dilution volume. The globule size of the optimized system was less than 200nm which could be an acceptable nanoemulsion size range. The zeta potential of the selected CN 7 SNEDDS formulation (cinnamon oil 30%; labrasol 60%; Capmul MCM C8 10%) was -29.5±0.63 with an average particle size distribution of 122nm. In vitro drug release studies showed remarkable increase in dissolution of CN7 SNEDDS compared to marketed formulation. In house developed HPLC method for determination of Rosuvastatin calcium in rat plasma was used in the bioavailability and pharmacokinetic evaluation. The relative bioavailability of self nanoemulsified formulation showed an enhanced bioavailability of 2.45 times greater than that of drug in suspension. The obtained plasma drug concentration data was processed with PKSolver 2.0 and it was best fit into the one compartment model. PMID:24012665

  12. Custom fractional factorial designs to develop atorvastatin self-nanoemulsifying and nanosuspension delivery systems – enhancement of oral bioavailability

    PubMed Central

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

    2015-01-01

    Poor water solubility of a drug is a major challenge in drug delivery research and a main cause for limited bioavailability and pharmacokinetic parameters. This work aims to utilize custom fractional factorial design to assess the development of self-nanoemulsifying drug delivery systems (SNEDDS) and solid nanosuspensions (NS) in order to enhance the oral delivery of atorvastatin (ATR). According to the design, 14 experimental runs of ATR SNEDDS were formulated utilizing the highly ATR solubilizing SNEDDS components: oleic acid, Tween 80, and propylene glycol. In addition, 12 runs of NS were formulated by the antisolvent precipitation–ultrasonication method. Optimized formulations of SNEDDS and solid NS, deduced from the design, were characterized. Optimized SNEDDS formula exhibited mean globule size of 73.5 nm, zeta potential magnitude of −24.1 mV, and 13.5 μs/cm of electrical conductivity. Optimized solid NS formula exhibited mean particle size of 260.3 nm, 7.4 mV of zeta potential, and 93.2% of yield percentage. Transmission electron microscopy showed SNEDDS droplets formula as discrete spheres. The solid NS morphology showed flaky nanoparticles with irregular shapes using scanning electron microscopy. The release behavior of the optimized SNEDDS formula showed 56.78% of cumulative ATR release after 10 minutes. Solid NS formula showed lower rate of release in the first 30 minutes. Bioavailability estimation in Wistar albino rats revealed an augmentation in ATR bioavailability, relative to ATR suspension and the commercial tablets, from optimized ATR SNEDDS and NS formulations by 193.81% and 155.31%, respectively. The findings of this work showed that the optimized nanocarriers enhance the oral delivery and pharmacokinetic profile of ATR. PMID:26150693

  13. Evaluation of critical formulation parameters in design and differentiation of self-microemulsifying drug delivery systems (SMEDDSs) for oral delivery of aciclovir.

    PubMed

    Janković, Jovana; Djekic, Ljiljana; Dobričić, Vladimir; Primorac, Marija

    2016-01-30

    The study investigated the influence of formulation parameters for design of self-microemulsifying drug delivery systems (SMEDDSs) comprising oil (medium chain triglycerides) (10%), surfactant (Labrasol(®), polysorbate 20, or Kolliphor(®) RH40), cosurfactant (Plurol(®) Oleique CC 497) (q.s. ad 100%), and cosolvent (glycerol or macrogol 400) (20% or 30%), and evaluate their potential as carriers for oral delivery of a poorly permeable antivirotic aciclovir (acyclovir). The drug loading capacity of the prepared formulations ranged from 0.18-31.66 mg/ml. Among a total of 60 formulations, three formulations meet the limits for average droplet size (Z-ave) and polydispersity index (PdI) that have been set for SMEDDSs (Z-ave≤100nm, PdI<0.250) upon spontaneous dispersion in 0.1M HCl and phosphate buffer pH 7.2. SMEDDSs with the highest aciclovir loading capacity (24.06 mg/ml and 21.12 mg/ml) provided the in vitro drug release rates of 0.325 mg cm(-2)min(-1) and 0.323 mg cm(-2)min(-1), respectively, and significantly enhanced drug permeability in the parallel artificial membrane permeability assay (PAMPA), in comparison with the pure drug substance. The results revealed that development of SMEDDSs with enhanced drug loading capacity and oral delivery potential, required optimization of hydrophilic ingredients, in terms of size of hydrophilic moiety of the surfactant, surfactant-to-cosurfactant mass ratio (Km), and log P of the cosolvent. PMID:26611669

  14. Design, fabrication and delivery of a miniature Cassegrainian concentrator solar array system

    NASA Technical Reports Server (NTRS)

    Kruer, Mark A.

    1987-01-01

    The optical design of the miniature Cassegrainian concentrator (MCC) element was improved for both offpoint and onpoint power capability. The cell stack design has shown no losses under the high short term thermal stresses imposed by component level test and is projected to be capable of greater than five years thermal cycle life in low Earth orbit. The structural design met all requirements for stiffness and flatness and requires adjustable inserts for fine tuning of the GFRP structure to meet flatness goals. The completed, fully populated small and large MCC panels deliverable under this contract perform electrically as expected. A solid acceptance inspection program to guarantee quality of all purchased parts, and continued manufacturing process improvements will make the MCC design a viable low cost alternative to standard flat panel technology. Minor improvements to the cell stack design of the MCC element can make significant improvements in both the performance and manufacturability of the MCC system.

  15. Technological Delivery Systems.

    ERIC Educational Resources Information Center

    Kennedy, Don; And Others

    A section on technological delivery systems, presented as part of the second Australian National Workshop on Distance Education (Perth, 1983), contains four papers on using technological resources to provide educational services to persons in isolated locations. The first paper, by Don Kennedy, covers the use of satellite broadcasting of course…

  16. Advances in Gene Delivery Systems

    PubMed Central

    Kamimura, Kenya; Suda, Takeshi; Zhang, Guisheng; Liu, Dexi

    2011-01-01

    The transfer of genes into cells, both in vitro and in vivo, is critical for studying gene function and conducting gene therapy. Methods that utilize viral and nonviral vectors, as well as physical approaches, have been explored. Viral vector-mediated gene transfer employs replication-deficient viruses such as retro-virus, adenovirus, adeno-associated virus and herpes simplex virus. A major advantage of viral vectors is their high gene delivery efficiency. The nonviral vectors developed so far include cationic liposomes, cationic polymers, synthetic peptides and naturally occurring compounds. These nonviral vectors appear to be highly effective in gene delivery to cultured cells in vitro but are significantly less effective in vivo. Physical methods utilize mechanical pressure, electric shock or hydrodynamic force to transiently permeate the cell membrane to transfer DNA into target cells. They are simpler than viral- and nonviral-based systems and highly effective for localized gene delivery. The past decade has seen significant efforts to establish the most desirable method for safe, effective and target-specific gene delivery, and good progress has been made. The objectives of this review are to (i) explain the rationale for the design of viral, nonviral and physical methods for gene delivery; (ii) provide a summary on recent advances in gene transfer technology; (iii) discuss advantages and disadvantages of each of the most commonly used gene delivery methods; and (iv) provide future perspectives. PMID:22200988

  17. Design and characterization of an ultrasonic lamb-wave power delivery system.

    PubMed

    Kural, Aleksander; Pullin, Rhys; Holford, Karen; Lees, Jonathan; Naylon, Jack; Paget, Christophe; Featherston, Carol

    2013-06-01

    In this paper, a novel design for an ultrasonic power transmission system designed for use in aircraft structural monitoring systems is described. The prototype system uses ultrasonic Lamb waves to carry energy along plates, such as those used in aircraft structures, and commercially available piezoelectric patch transducers as the transmitter and receiver. This sets it apart from other acoustic power transmission systems reported to date. The optimum configuration transmitted 12.7 mW of power across a distance of 54 cm in a 1.5-mm-thick aluminum plate, while being driven by a 20-Vpp, 35-kHz sinusoidal electric signal. This is in the same order of magnitude as the power required by the wireless sensors nodes of a structural health monitoring system currently being developed by Cardiff University and its partners. Thus, the power transmission system can be considered a viable component of the power source combination considered for the sensor nodes, which will also include vibration and thermal energy harvesting. The paper describes the design and optimization of the transmission and reception circuits with the use of inductive compensation. The use of laser vibrometry to characterize the transducers and to understand the signal propagation between them is also reported. PMID:25004476

  18. A Lindenmayer system-based approach for the design of nutrient delivery networks in tissue constructs.

    PubMed

    Yasar, Ozlem; Lan, Shih-Feng; Starly, Binil

    2009-12-01

    Large thick tissue constructs have reported limited success primarily due to the inability of cells to survive deep within the scaffold. Without access to adequate nutrients, cells placed deep within the tissue construct will die out, leading to non-uniform tissue regeneration. Currently, there is a necessity to design nutrient conduit networks within the tissue construct to enable cells to survive in the matrix. However, the design of complex networks within a tissue construct is challenging. In this paper, we present the Lindenmayer system, an elegant fractal-based language algorithm framework, to generate conduit networks in two- and three-dimensional architecture with several degrees of complexity. The conduit network maintains a parent-child relationship between each branch of the network. Several L-system parameters have been studied-branching angle, branch length, ratio of parent to child branch diameter, etc-to simulate several architectures under a given L-system notation. We have also presented a layered manufacturing-based UV-photopolymerization process using the Texas Instruments DLP system to fabricate the branched structures. This preliminary work showcases the applicability of L-system-based construct designs to drive scaffold fabrication systems. PMID:20811113

  19. Evaluating Learning Management System (LMS)-Facilitated Delivery of Universal Design for Learning (UDL)

    ERIC Educational Resources Information Center

    Bryans Bongey, Sarah

    2012-01-01

    This quantitative study involved 157 students in two sections of an undergraduate class in general biology, as well as one instructor who taught both sections of the course. It used resources from the Center for Applied Special Technologies (CAST) to evaluate the viability of a Learning Management System (LMS) to provide Universal Design for…

  20. Conceptual design of a closed loop nutrient solution delivery system for CELSS implementation in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Schwartzkopf, Steven H.; Oleson, Mel W.; Cullingford, Hatice S.

    1989-01-01

    This paper describes the results of a study to develop a conceptual design for an experimental, closed-loop fluid handling system capable of monitoring, controlling, and supplying nutrient solution to higher plants. The Plant Feeder Experiment (PFX) is designed to be flight tested in a micro-gravity (micro-g) environment and was developed under NASA's In-Space Technology Experiments Program (INSTEP). When flown, PFX will provide information on both the generic problems of micro-g fluid handling and the specific problems associated with the delivery of nutrient solution in a micro-g environment. The experimental hardware is designed to fit into two middeck lockers on the Space Shuttle, and incorporates several components that have previously been flight tested.

  1. Design and in vitro evaluation of a novel vaginal drug delivery system based on gelucire.

    PubMed

    Geeta, M Patel; Madhabhai, M Patel

    2009-04-01

    Carbamazepine indicated for the control of epilepsy, undergoes extensive hepatic first-pass metabolism after oral administration. A vaginal dosage form of carbamazepine is not commercially available. Conventional suppository having poor retention in the vaginal tract, as they are removed in a short time by the tract's self-cleansing action, having poor patient compliance. To overcome such problems, delivery system with mucoadhesive polymers polyox WSR N-60K and Ucarflock 302 that prolong drug permanence on the vaginal mucosa were developed. In the present study the suitability of gelucires to formulate vaginal pesseries was investigated. The possible modification of carbamazepine release kinetics by using gelucires blends and hydrophilic additives in the pesseries was evaluated. It was observed that among gelucire grades melting point higher than 37 degrees C, the release rate proved to be highly dependant on HLB value and matrix composition. In most of the formulations carbamazepine release occurred by disintegration and erosion of the matrices which is depending upon the vehicle employed. The aging study revealed that the formulations containing G50/13 and G50/13-G44/14 blends undergo some changes during one year of shelf aging. From the results obtained it can be concluded that different gelucire grades and their blends along with hydrophilic polymer could be successesively used to formulate prolong release carbamazepine pesseries. PMID:19450222

  2. Caffeic Acid-PLGA Conjugate to Design Protein Drug Delivery Systems Stable to Irradiation

    PubMed Central

    Selmin, Francesca; Puoci, Francesco; Parisi, Ortensia I.; Franzé, Silvia; Musazzi, Umberto M.; Cilurzo, Francesco

    2015-01-01

    This work reports the feasibility of caffeic acid grafted PLGA (g-CA-PLGA) to design biodegradable sterile microspheres for the delivery of proteins. Ovalbumin (OVA) was selected as model compound because of its sensitiveness of γ-radiation. The adopted grafting procedure allowed us to obtain a material with good free radical scavenging properties, without a significant modification of Mw and Tg of the starting PLGA (Mw PLGA = 26.3 ± 1.3 kDa vs. Mw g-CA-PLGA = 22.8 ± 0.7 kDa; Tg PLGA = 47.7 ± 0.8 °C vs. Tg g-CA-PLGA = 47.4 ± 0.2 °C). By using a W1/O/W2 technique, g-CA-PLGA improved the encapsulation efficiency (EE), suggesting that the presence of caffeic residues improved the compatibility between components (EEPLGA = 35.0% ± 0.7% vs. EEg-CA-PLGA = 95.6% ± 2.7%). Microspheres particle size distribution ranged from 15 to 50 µm. The zeta-potential values of placebo and loaded microspheres were −25 mV and −15 mV, respectively. The irradiation of g-CA-PLGA at the dose of 25 kGy caused a less than 1% variation of Mw and the degradation patterns of the non-irradiated and irradiated microspheres were superimposable. The OVA content in g-CA-PLGA microspheres decreased to a lower extent with respect to PLGA microspheres. These results suggest that g-CA-PLGA is a promising biodegradable material to microencapsulate biological drugs. PMID:25569163

  3. Multifunctional SMA-based smart inhaler system for improved aerosol drug delivery: design and fabrication

    NASA Astrophysics Data System (ADS)

    Pausley, Matthew E.; Seelecke, Stefan

    2008-03-01

    This paper documents the development of a prototype smart aerosol drug inhaler system using shape memory alloy (SMA) actuators. Unlike conventional dispersed-release inhalers, the smart inhaler system releases the aerosol drug in a very small area within the mouth inlet. Kleinstreuer and Zhang [1] have found that controlled release in the mouth inlet increases drug efficiency and allows targeting of specific sites within the lung. The methodology has been validated numerically and experimentally using fixed-exit position inhalers. The design presented in this work, however, allows for variation of nozzle exit position using SMA wire actuators in a combined actuator/sensor role. In contrast to other possible mechanisms, SMA wires are lightweight, require low power, and are the least obstructive to the flow of air through the inhaler. The dual actuator/sensor nature of the SMA wires (via resistance measurement) further simplifies the design. Solutions and insights into several SMA actuator design challenges are presented. SMA wire actuator characteristics such as achievable stroke and their effect on the design are highlighted. Consideration of actuator force requirements and the capabilities of SMA wires and studied. The problems posed by the thermal characteristics of SMA wires and innovative solutions are reported.

  4. Transdermal drug delivery systems of a beta blocker: design, in vitro, and in vivo characterization.

    PubMed

    Aqil, M; Sultana, Yasmin; Ali, Asgar; Dubey, Kiran; Najmi, A K; Pillai, K K

    2004-01-01

    The matrix type transdermal drug delivery systems (TDDS) of metoprolol were prepared by film casting technique using a fabricated stainless steel film casting apparatus and characterized in vitro by drug release, skin permeation, skin irritation, and in vivo pharmacodynamic and stability studies. Four formulations were prepared that differed in the ratio of matrix forming polymers. Formulations M-1, M-2, M-3, and M-4 were composed of Eudragit RL-100 and polyvinyl acetate with the following ratios: 2:8, 4:6, 6:4, and 8:2, respectively. All the four formulations carried 10% (w/w) of metoprolol tartrate, 5% (w/w) of dibutylphthalate, and 5% (w/w) of (+/-) menthol in dichloromethane:isopropyl alcohol (80:20 v/v). Cumulative amount of drug released in 48 hr from the four formulations was 79.16%, 81.17%, 85.98%, and 95.04%. The corresponding values for cumulative amount of drug permeated for the said formulations were 59.72%, 66.52%, 77.36%, and 90.38%. On the basis of in vitro drug release and skin permeation performance, formulation M-4 was found to be better than the other three formulations and it was selected as the optimized formulation. The formulation appeared to be stable when stored at 40 degrees C and 75% RH with negligible degradation of the drug. The TDDS was found to be free of any skin irritation as suggested by skin irritation score of 1.16 (<2.00) under Draize score test. Statistically significant reduction in mean blood pressure (p < .01) was achieved in methyl prednisolone-induced hypertensive rats on treatment with the TDDS. PMID:15168788

  5. Engineering Design and Molecular Dynamics of Mucoadhesive Drug Delivery Systems as Targeting Agents

    PubMed Central

    Serra, Laura; Doménech, Josep; Peppas, Nicholas

    2009-01-01

    The goal of this critical review is to provide a critical analysis of the chain dynamics responsible for the action of micro- and nanoparticles of mucoadhesive biomaterials. The objective of using bioadhesive controlled drug delivery devices is to prolong their residence at a specific site of delivery, thus enhancing the drug absorption process. These mucoadhesive devices can protect the drug during the absorption process in addition to protecting it on its route to the delivery site. The major emphasis of recent research on mucoadhesive biomaterials has been on the use of adhesion promoters, which would enhance the adhesion between synthetic polymers and mucus. The use of adhesion promoters such as linear or tethered polymer chains is a natural result of the diffusional characteristics of adhesion. Mucoadhesion depends largely on the structure of the synthetic polymer gels used in controlled release applications. PMID:18976706

  6. Evaluating Learning Management System (LMS)-facilitated Delivery of Universal Design for Learning (UDL)

    NASA Astrophysics Data System (ADS)

    Bryans Bongey, Sarah

    This quantitative study involved 157 students in two sections of an undergraduate class in general biology, as well as one instructor who taught both sections of the course. It used resources from the Center for Applied Special Technologies (CAST) to evaluate the viability of a Learning Management System (LMS) to provide Universal Design for Learning (UDL). It also measured and tracked the instructor's level of efficacy in sustaining UDL approaches throughout the semester. In an effort to identify the UDL's specific outcomes or benefits to students, this study used a pre- and post- test to identify the treatment's impact on student engagement. Findings indicated that the LMS could be designed to comply with UDL guidelines, and the instructor was able to establish a high level of efficacy in maintaining that UDL design. However, based on the statistical analysis of pre- and post-test responses from control vs. treatment groups of students, the treatment was seen to have no significant effect in the area of student engagement. Overall, the study added to the literature by suggesting (a) the viability of the LMS as a means of providing UDL approaches, (b) the promise of the LMS as a tool faculty can use to deliver UDL with a high level of efficacy, and (c) the design's lack of effect in the area of student engagement. The fact that this study was limited to a single brand of LMS (Blackboard), a single instructor, and a single group of students underscores the need for further research.

  7. Continuing Professional Education Delivery Systems.

    ERIC Educational Resources Information Center

    Weeks, James P.

    This investigation of delivery systems for continuing professional education provides an overview of current operational delivery systems in continuing professional education, drawing on experience as found in the literature. Learning theories and conclusions are woven into the descriptive text. Delivery systems profiled in the paper include the…

  8. MEMS: Enabled Drug Delivery Systems.

    PubMed

    Cobo, Angelica; Sheybani, Roya; Meng, Ellis

    2015-05-01

    Drug delivery systems play a crucial role in the treatment and management of medical conditions. Microelectromechanical systems (MEMS) technologies have allowed the development of advanced miniaturized devices for medical and biological applications. This Review presents the use of MEMS technologies to produce drug delivery devices detailing the delivery mechanisms, device formats employed, and various biomedical applications. The integration of dosing control systems, examples of commercially available microtechnology-enabled drug delivery devices, remaining challenges, and future outlook are also discussed. PMID:25703045

  9. Planning health care delivery systems.

    PubMed Central

    Baum, M A; Bergwall, D F; Reeves, P N

    1975-01-01

    The increasing concern and interest in the health delivery system in the United States has placed the health system planners in a difficult position. They are inadequately prepared, in many cases, to deal with the management techniques that have been designed for use with system problems. This situation has been compounded by the failure, until recently, of educational programs to train new health professionals in these techniques. Computer simulation is a technique that allows the planners dynamic feedback on his proposed plans. This same technique provides the planning student with a better understanding of the systems planning process. PMID:1115292

  10. Nanovehicular Intracellular Delivery Systems

    PubMed Central

    PROKOP, ALES; DAVIDSON, JEFFREY M.

    2013-01-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood–brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list “elementary” phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  11. Nanovehicular intracellular delivery systems.

    PubMed

    Prokop, Ales; Davidson, Jeffrey M

    2008-09-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood-brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list "elementary" phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  12. Design of PLGA-based depot delivery systems for biopharmaceuticals prepared by spray drying.

    PubMed

    Wan, Feng; Yang, Mingshi

    2016-02-10

    Currently, most of the approved protein and peptide-based medicines are delivered via conventional parenteral injection (intramuscular, subcutaneous or intravenous). A frequent dosing regimen is often necessary because of their short plasma half-lives, causing poor patient compliance (e.g. pain, abscess, etc.), side effects owing to typical peak-valley plasma concentration time profiles, and increased costs. Among many sustained-release formulations poly lactic-co-glycolic acid (PLGA)-based depot microparticle systems may represent one of the most promising approaches to provide protein and peptide drugs with a steady pharmacokinetic/pharmacodynamic profile maintained for a long period. However, the development of PLGA-based microparticle systems is still impeded by lack of easy, fast, effective manufacturing technologies. The aim of this paper is to review recent advances in spray drying, a one-step, continuous microencapsulation process, for manufacturing of PLGA-based depot microparticle systems with a focus on the recent efforts on understanding of the role of nozzle design in the microencapsulation of proteins/peptides, and the effect of critical solvent properties and process parameters on the critical quality attributes of the spray-dried microparticles. PMID:26688034

  13. Secondary fuel delivery system

    DOEpatents

    Parker, David M.; Cai, Weidong; Garan, Daniel W.; Harris, Arthur J.

    2010-02-23

    A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas. The system delivers a secondary fuel/diluent mixture to a secondary combustion zone located along the length of the transition piece, while reducing the impact of elevated vibration levels found within the transition piece and avoiding the heat dissipation difficulties often associated with traditional vibration reduction methods.

  14. Design and evaluation of mucoadhesive beads of glipizide as a controlled release drug delivery system.

    PubMed

    Bera, K; Khanam, J; Mohanraj, K P; Mazumder, B

    2014-01-01

    The present work aims at the development of a low-cost controlled release system of glipizide beads embedded in pectin to overcome the problem of frequent dosing of drug. The method of preparation has been optimised by experimental design to achieve satisfactory responses with respect to controlling variables. The controlling variables are X1, drug-polymer ratio; X2, surfactant concentration and X3, isooctane-acetone ratio. The most effective combination is X1(1:6), X2(1%), X3(50:50). Various parameters such as mucoadhesivity and swellability of beads, characterisation, dissolution, stability, ex vivo absorption and in vivo (Oral glucose tolerance test in rat) studies were performed with the optimised product. The optimised product was found quiet satisfactory that showed yield of 86.78%, drug entrapment efficiency (DEE) of 87.38% and drug release was extended up to 18 h. The present formulation of glipizide is a promising multiparticulate system of glipizide with significant hypoglycemic effect, and moreover it was prepared rapidly with ease. PMID:24047213

  15. Design and statistical optimization of an effervescent floating drug delivery system of theophylline using response surface methodology.

    PubMed

    Srikanth Meka, Venkata; Ee Li, Chew; Sheshala, Ravi

    2016-03-01

    The aim of this research was to formulate effervescent floating drug delivery systems of theophylline using different release retarding polymers such as ethyl cellulose, Eudragit® L100, xanthan gum and polyethylene oxide (PEO) N12K. Sodium bicarbonate was used as a gas generating agent. Direct compression was used to formulate floating tablets and the tablets were evaluated for their physicochemical and dissolution characteristics. PEO based formulations produced better drug release properties than other formulations. Hence, it was further optimized by central composite design. Further subjects of research were the effect of formulation variables on floating lag time and the percentage of drug released at the seventh hour (D7h). The optimum quantities of PEO and sodium bicarbonate, which had the highest desirability close to 1.0, were chosen as the statistically optimized formulation. No interaction was found between theophylline and PEO by Fourier Transformation Infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) studies. PMID:26959542

  16. Designing Paclitaxel Drug Delivery Systems Aimed at Improved Patient Outcomes: Current Status and Challenges

    PubMed Central

    Surapaneni, Madhu S.; Das, Sudip K.; Das, Nandita G.

    2012-01-01

    Paclitaxel is one of the most widely used and effective antineoplastic agents derived from natural sources. It has a wide spectrum of antitumor activity, particularly against ovarian cancer, breast cancer, nonsmall cell lung cancer, head and neck tumors, Kaposi's sarcoma, and urologic malignancies. It is a highly lipophilic compound with a log P value of 3.96 and very poor aqueous solubility of less than 0.01 mg/mL. In addition, the compound lacks functional groups that are ionizable which could potentially lead to an increase in its solubility with the alteration in pH. Therefore, the delivery of paclitaxel is associated with substantial challenges. Until the introduction of Abraxane, only commercial formulation was solution of paclitaxel in cremophor, which caused severe side effects. However, in recent years, a number of approaches have been reported to solubilize paclitaxel using cosolvents and inclusion complexes. In addition, innovative approaches have been reported for passive targeting of tumors using nanoparticles, nanosuspensions, liposomes, emulsions, micelles, implants, pastes and gels. All approaches for delivery of improved therapeutic outcome have been discussed in this paper. PMID:22934190

  17. Design, development, and optimization of polymeric based-colonic drug delivery system of naproxen.

    PubMed

    Sharma, Pooja; Chawla, Anuj; Pawar, Pravin

    2013-01-01

    The aim of present investigation deals with the development of time-dependent and pH sensitive press-coated tablets for colon specific drug delivery of naproxen. The core tablets were prepared by wet granulation method then press coated with hydroxypropyl cellulose (HPC) or Eudragit RSPO : RLPO mixture and further coated with Eudragit S-100 by dip immerse method. The in vitro drug release study was conducted in different dissolution media such as pH 1.2, 6.8, and 7.4 with or without rat caecal content to simulate GIT conditions. Surface morphology and cross-sectional view of the tablets were visualized by scanning electron microscopy (SEM). All prepared batches were in compliance with the pharmacopoeial standards. The tablets which are compression coated with HPC followed by Eudragit S-100 coated showed highest in vitro drug release of 98.10% in presence of rat caecal content. The SEM of tablets suggested that the number of pores got increased in pH 7.4 medium followed by dissolution of coating layer. The tablets coat erosion study suggested that the lag time depends upon the coating concentrations of polymers. A time-dependent hydrophilic polymer and pH sensitive polymer based press-coated tablets of naproxen were promising delivery for colon targeting. PMID:24198725

  18. Drug Delivery Through the Skin: Molecular Simulations of Barrier Lipids to Design more Effective Noninvasive Dermal and Transdermal Delivery Systems for Small Molecules Biologics and Cosmetics

    SciTech Connect

    J Torin Huzil; S Sivaloganathan; M Kohandel; M Foldvari

    2011-12-31

    The delivery of drugs through the skin provides a convenient route of administration that is often preferable to injection because it is noninvasive and can typically be self-administered. These two factors alone result in a significant reduction of medical complications and improvement in patient compliance. Unfortunately, a significant obstacle to dermal and transdermal drug delivery alike is the resilient barrier that the epidermal layers of the skin, primarily the stratum corneum, presents for the diffusion of exogenous chemical agents. Further advancement of transdermal drug delivery requires the development of novel delivery systems that are suitable for modern, macromolecular protein and nucleotide therapeutic agents. Significant effort has already been devoted to obtain a functional understanding of the physical barrier properties imparted by the epidermis, specifically the membrane structures of the stratum corneum. However, structural observations of membrane systems are often hindered by low resolutions, making it difficult to resolve the molecular mechanisms related to interactions between lipids found within the stratum corneum. Several models describing the molecular diffusion of drug molecules through the stratum corneum have now been postulated, where chemical permeation enhancers are thought to disrupt the underlying lipid structure, resulting in enhanced permeability. Recent investigations using biphasic vesicles also suggested a possibility for novel mechanisms involving the formation of complex polymorphic lipid phases. In this review, we discuss the advantages and limitations of permeation-enhancing strategies and how computational simulations, at the atomic scale, coupled with physical observations can provide insight into the mechanisms of diffusion through the stratum corneum.

  19. Use of the Systems Approach to Training Design and Delivery in Japanese Corporations.

    ERIC Educational Resources Information Center

    Keller, John M.; Taguchi, Mina

    1996-01-01

    Surveyed 45 Japanese corporations to determine common training methods and use of systematic design and development processes. Results indicate that overall there was more internal classroom training than on-the-job training and that only two of the companies had a formal, systematic approach to instruction design and development. (JMV)

  20. Novel mucoadhesion tests for polymers and polymer-coated particles to design optimal mucoadhesive drug delivery systems.

    PubMed

    Takeuchi, Hirofumi; Thongborisute, Jringjai; Matsui, Yuji; Sugihara, Hikaru; Yamamoto, Hiromitsu; Kawashima, Yoshiaki

    2005-11-01

    To design an effective particulate drug delivery system having mucoadhesive function, several mucoadhesion tests for polymers and the resultant particulate systems were developed. Mucin particle method is a simple mucoadhesion test for polymers, in which the commercial mucin particles are used. By measuring the change in particle size or zeta potential of the mucin particle in a certain concentration of polymer solution, we could estimate the extent of their mucoadhesive property. BIACORE method is also a novel mucoadhesion test for polymers. On passing through the mucin suspension on the polymer-immobilized chip of BIACORE instrument, the interaction was quantitatively evaluated with the change in its response diagram. By using these mucoadhesion tests, we detected a strong mucoadhesive property of several types of chitosan and Carbopol. Evaluation of mucoadhesive property of polymer-coated particulate systems was demonstrated with the particle counting method developed by us. To detect the mucoadhesive phenomena in the intestinal tract, we observed the rat intestine with the confocal laser scanning microscope (CLSM) after oral administration of the particulate systems. The resultant photographs clearly showed a longer retention of submicron-sized chitosan-coated liposomes (ssCS-Lip) in the intestinal tract than other liposomal particles tested such as non-coated liposomes and chitosan-coated multilamellar one. These observations explained well the superiority of the ssCS-Lip as drug carrier in oral administration of calcitonin in rats than other liposomal particles. PMID:16169120

  1. Dynamic modeling, simulation and control design of a parafoil-payload system for ship launched aerial delivery system (SLADS)

    NASA Astrophysics Data System (ADS)

    Puranik, Anand S.

    The objective of this research was to develop a high-fidelity dynamic model of a parafoil-payload system with respect to its application for the Ship Launched Aerial Delivery System (SLADS). SLADS is a concept in which cargo can be transfered from ship to shore using a parafoil-payload system. It is accomplished in two phases: An initial towing phase when the glider follows the towing vessel in a passive lift mode and an autonomous gliding phase when the system is guided to the desired point. While many previous researchers have analyzed the parafoil-payload system when it is released from another airborne vehicle, limited work has been done in the area of towing up the system from ground or sea. One of the main contributions of this research was the development of a nonlinear dynamic model of a towed parafoil-payload system. After performing an extensive literature review of the existing methods of modeling a parafoil-payload system, a five degree-of-freedom model was developed. The inertial and geometric properties of the system were investigated to predict accurate results in the simulation environment. Since extensive research has been done in determining the aerodynamic characteristics of a paraglider, an existing aerodynamic model was chosen to incorporate the effects of air flow around the flexible paraglider wing. During the towing phase, it is essential that the parafoil-payload system follow the line of the towing vessel path to prevent an unstable flight condition called 'lockout'. A detailed study of the causes of lockout, its mathematical representation and the flight conditions and the parameters related to lockout, constitute another contribution of this work. A linearized model of the parafoil-payload system was developed and used to analyze the stability of the system about equilibrium conditions. The relationship between the control surface inputs and the stability was investigated. In addition to stability of flight, one more important objective

  2. Engineering strategies for the design of plant nutrient delivery systems for use in space: approaches to countering microbiological contamination

    NASA Technical Reports Server (NTRS)

    Gonzales, A. A.; Schuerger, A. C.; Barford, C.; Mitchell, R.

    1996-01-01

    Microbiological contamination of crops within space-based plant growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growth systems in space habitats. Microorganisms transported into space most likely will occur as surface contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests, and technology developments, structured to allow the development of prudent engineering solutions also will be presented.

  3. Engineering Strategies for the Design of Plant Nutrient Delivery Systems for Use in Space: Approaches to Countering Microbiological Contamination

    NASA Technical Reports Server (NTRS)

    Gonzales, A. A.; Schuerger, A. C.; Mitchell, R.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Microbiological contamination of crops within space-based crop growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms, have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growing systems in space habitats. Microorganisms transported into space will most likely occur as contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests and technology developments, structured to allow the development of prudent engineering solutions, will also be presented.

  4. Engineering strategies for the design of plant nutrient delivery systems for use in space: approaches to countering microbiological contamination

    NASA Astrophysics Data System (ADS)

    Gonzales, A. A.; Schuerger, A. C.; Barford, C.; Mitchell, R.

    Microbiological contamination of crops within space-based plant growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growth systems in space habitats. Microorganisms transported into space most likely will occur as surface contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests, and technology developments, structured to allow the development of prudent engineering solutions also will be presented.

  5. Design of Chronomodulated Drug Delivery System of Valsartan: In Vitro Characterization

    PubMed Central

    Sokar, M.; Hanafy, A.; Elkamel, A.; El-Gamal, S.

    2015-01-01

    The aim of the present study was to design and evaluate a chronomodulated time-clock pulsatile tablets of valsartan to release it after a certain lag time, independent of the gastrointestinal pH, in its absorption window to cope with the circadian rhythm of human body for blood pressure elevation. Core tablets were prepared by direct compression of a homogenous mixture of valsartan, Avicel PH101, croscarmellose sodium, magnesium stearate and Aerosil. The core tablets were then sprayed coated with a sealing layer formed of ethyl cellulose that was subsequently coated with a release-controlling layer. Three different aqueous dispersions namely; carnauba wax or beeswax or a mixture in a ratio of 2.5:1, respectively, were used to form five time-clock tablet formulations having the release controlling layer with different thickness {B5, B10, B20, BW5 and CW5}. Quality control testing were carried out to the core tablets. Differential scanning calorimetry was also performed to detect the possible drug excipient interaction in the core tablet formulation. The release was carried out, for the prepared time-clock tablet formulations, in 0.1 N hydrochloric acid for the first 2 h, followed by phosphate buffer (pH 6.8) for 4.5 h. The effect of pH on valsartan release was studied through a release study in 0.1 N hydrochloric acid for 6.5 h. Two phase dissolution study was performed to the selected time-clock tablet formulation to predict the drug permeation through the gastrointestinal tract. Stability study of the selected formula was performed at 25°/60% RH and at 40°/75% RH for 3 months. Results showed that a release-controlling layer composed of a mixture of carnauba wax and beeswax in a ratio of 2.5:1 showed a reasonable release lag time. The release lag time of the tablets increased with the increase of the coat thickness, thus B20>B10>B5 with corresponding lag time values of 4.5, 3 and 2.5 h, respectively. Selected B5 tablet formula exhibited a reasonable lag time

  6. Design of Chronomodulated Drug Delivery System of Valsartan: In Vitro Characterization.

    PubMed

    Sokar, M; Hanafy, A; Elkamel, A; El-Gamal, S

    2015-01-01

    The aim of the present study was to design and evaluate a chronomodulated time-clock pulsatile tablets of valsartan to release it after a certain lag time, independent of the gastrointestinal pH, in its absorption window to cope with the circadian rhythm of human body for blood pressure elevation. Core tablets were prepared by direct compression of a homogenous mixture of valsartan, Avicel PH101, croscarmellose sodium, magnesium stearate and Aerosil. The core tablets were then sprayed coated with a sealing layer formed of ethyl cellulose that was subsequently coated with a release-controlling layer. Three different aqueous dispersions namely; carnauba wax or beeswax or a mixture in a ratio of 2.5:1, respectively, were used to form five time-clock tablet formulations having the release controlling layer with different thickness {B5, B10, B20, BW5 and CW5}. Quality control testing were carried out to the core tablets. Differential scanning calorimetry was also performed to detect the possible drug excipient interaction in the core tablet formulation. The release was carried out, for the prepared time-clock tablet formulations, in 0.1 N hydrochloric acid for the first 2 h, followed by phosphate buffer (pH 6.8) for 4.5 h. The effect of pH on valsartan release was studied through a release study in 0.1 N hydrochloric acid for 6.5 h. Two phase dissolution study was performed to the selected time-clock tablet formulation to predict the drug permeation through the gastrointestinal tract. Stability study of the selected formula was performed at 25°/60% RH and at 40°/75% RH for 3 months. Results showed that a release-controlling layer composed of a mixture of carnauba wax and beeswax in a ratio of 2.5:1 showed a reasonable release lag time. The release lag time of the tablets increased with the increase of the coat thickness, thus B20>B10>B5 with corresponding lag time values of 4.5, 3 and 2.5 h, respectively. Selected B5 tablet formula exhibited a reasonable lag time

  7. Resistive-wall wake effect in the beam delivery system

    SciTech Connect

    J.R. Delayen; Juhao Wu; T.O. Raubenheimer; Jiunn-Ming Wang

    2004-08-16

    General formulae for resistive-wall induced beam dilution are presented and then applied to the final beam delivery system of linear colliders. Criteria for the design of final beam delivery systems are discussed.

  8. Design of optimal light delivery system for co-registered transvaginal ultrasound and photoacoustic imaging of ovarian tissue

    PubMed Central

    Salehi, Hassan S.; Kumavor, Patrick D.; Li, Hai; Alqasemi, Umar; Wang, Tianheng; Xu, Chen; Zhu, Quing

    2015-01-01

    A hand-held transvaginal probe suitable for co-registered photoacoustic and ultrasound imaging of ovarian tissue was designed and evaluated. The imaging probe consists of an ultrasound transducer and four 1-mm-core multi-mode optical fibers both housed in a custom-made sheath. The probe was optimized for the highest light delivery output and best beam uniformity on tissue surface, by simulating the light fluence and power output for different design parameters. The laser fluence profiles were experimentally measured through chicken breast tissue and calibrated intralipid solution at various imaging depths. Polyethylene tubing filled with rat blood mimicking a blood vessel was successfully imaged up to ∼30 mm depth through porcine vaginal tissue at 750 nm. This imaging depth was achieved with a laser fluence on the tissue surface of 20 mJ/cm2, which is below the maximum permissible exposure (MPE) of 25 mJ/cm2 recommended by the American National Standards Institute (ANSI). Furthermore, the probe imaging capability was verified with ex vivo imaging of benign and malignant human ovaries. The co-registered images clearly showed different vasculature distributions on the surface of the benign cyst and the malignant ovary. These results suggest that our imaging system has the clinical potential for in vivo imaging and characterization of ovarian tissues. PMID:26640774

  9. Design and development of ethosomal transdermal drug delivery system of valsartan with preclinical assessment in Wistar albino rats.

    PubMed

    Bhosale, Sagar S; Avachat, Amelia M

    2013-06-01

    Valsartan (VLT) is a highly selective and orally active antihypertensive drug. However, its oral administration is associated with drawbacks like low bioavailability. The objective of this study was to design and develop a transdermal delivery system for VLT using ethosomal carriers to investigate their enhanced transdermal delivery potential. VLT ethosomes were prepared by cold method. VLT ethosomes were characterized by scanning electron microscopy. The prepared ethanolic liposomes were characterized to be spherical having low polydispersity of nano-size range with good entrapment efficiency. ETC5 ethosomal suspension with 4% of phospholipon 90H and 40% of ethanol was found to have highest entrapment efficiency, i.e. 80.230 ± 0.8748%. The permeation study of ethosomes was evaluated by ex vivo diffusion study through rat abdominal skin using Franz's diffusion cells and ETC5 ethosomal suspension was found to have highest permeation with flux of 92.819 ± 1.539 µg/cm²/h, when compared to the permeation profiles of drug solutions either in water or in a water-ethanol mixture. Transdermal application of ethosomal VLT on Wistar rats showed better and prolonged antihypertensive activity in comparison to orally administered VLT suspension by virtue of transdermal permeation through Wistar rat skin. Histopathological study of skin applied with ETC5 showed intercellular permeation across skin by dissolving intercellular lipids in epidermis without causing any rigorous changes in the skin cellular structure. In conclusion, ethosomes enabled the transdermal permeation of VLT, which amply proves its superiority over oral administration for antihypertensive treatment. PMID:23324030

  10. Enterprise Systems (ES) Software in Business School Curriculum--Evaluation of Design and Delivery

    ERIC Educational Resources Information Center

    Seethamraju, Ravi

    2007-01-01

    Considering the increasing importance of enterprise systems in business, and their pedagogical value in demonstrating business process orientation and concepts of integration, several universities have incorporated popular enterprise system (ES) software products such as SAP R/3 into their business school curricula. This paper describes an attempt…

  11. Designer protein delivery: From natural to engineered affinity-controlled release systems.

    PubMed

    Pakulska, Malgosia M; Miersch, Shane; Shoichet, Molly S

    2016-03-18

    Exploiting binding affinities between molecules is an established practice in many fields, including biochemical separations, diagnostics, and drug development; however, using these affinities to control biomolecule release is a more recent strategy. Affinity-controlled release takes advantage of the reversible nature of noncovalent interactions between a therapeutic protein and a binding partner to slow the diffusive release of the protein from a vehicle. This process, in contrast to degradation-controlled sustained-release formulations such as poly(lactic-co-glycolic acid) microspheres, is controlled through the strength of the binding interaction, the binding kinetics, and the concentration of binding partners. In the context of affinity-controlled release--and specifically the discovery or design of binding partners--we review advances in in vitro selection and directed evolution of proteins, peptides, and oligonucleotides (aptamers), aided by computational design. PMID:26989257

  12. Characterization and design of a low-power wireless power delivery system

    NASA Astrophysics Data System (ADS)

    Falkenstein, Erez Avigdor

    There is an increased demand for wireless sensors for data gathering and transmission where running wires to power a device or changing/charging batteries is difficult. Often the data is gathered at locations that are difficult to access, that need to be covert, and/or where the sensors cannot be easily maintained. Some examples are implanted sensors for medical diagnostics and therapy, structural monitoring sensors, sensors inside hazardous manufacturing or other hazardous environments, etc. For any low power sensor that operates at a low duty cycle, and in an environment with low levels of light or vibration, RF wireless powering offers the potential for maintenance-free operation. The thesis focuses on a design methodology for low-power non-directional far-field wireless powering. The power receiver consists of one or more antennae which receive plane waves transmitted by the powering source, and deliver the RF power to a rectifying element. The resulting DC power is optimally transferred to the electronic application via a power management circuit. The powering is independent of the electronic application which can include wireless transmission of sensor data. The design and implementation of an integrated rectifier-antenna at low incident power densities (from 25--200 muW/cm2) is presented. Nonlinear source-pull measurements and harmonic balance simulations are used for finding the optimal rectifying device RF and DC impedances for efficient rectification. Experimental results show that an antenna design with a specific complex impedance reaches the highest rectification efficiency. Several examples of the design methodology will be shown. In specific, characterization of a rectifying patch antenna at frequency of 2.45GHz will be detailed, with an optimal RF impedance of 137+j149O and an optimal DC load of 365O resulting in RF to DC conversion efficiency of 63% for the rectifier alone and 56% for the total rectifying antenna.

  13. Design and In Vivo Anti-Inflammatory Effect of Ketoprofen Delayed Delivery Systems.

    PubMed

    Cerciello, Andrea; Auriemma, Giulia; Morello, Silvana; Pinto, Aldo; Del Gaudio, Pasquale; Russo, Paola; Aquino, Rita P

    2015-10-01

    For the treatment of inflammatory-based diseases affected by circadian rhythms, the development of once-daily dosage forms is required to target early morning symptoms. In this study, Zn-alginate beads containing ketoprofen (K) were developed by a tandem technique prilling/ionotropic gelation. The effect of main critical variables on particles micromeritics, inner structure as well as on drug loading and in vitro drug release was studied. The in vivo anti-inflammatory efficacy was evaluated using a modified protocol of carrageenan-induced edema in rat paw administering beads to rats by oral gavage at 0, 3, or 5 h before edema induction. Good drug loading and desired particle size and morphology were obtained for the optimized formulation F20. In vitro dissolution studies showed that F20 had a gastroresistant behavior and delayed release of the drug in simulated intestinal fluid. The in vitro delayed release pattern was clearly reflected in the prolonged anti-inflammatory effect in vivo of F20, compared to pure ketoprofen; F20, administered 3 h before edema induction, showed a significant anti-inflammatory activity, reducing maximum paw volume in response to carrageenan injection, whereas no response was observed for ketoprofen. The designed beads appear a promising platform suitable for a delayed release of anti-inflammatory drugs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3451-3458, 2015. PMID:26088065

  14. Delivery methods for LVSD systems

    NASA Astrophysics Data System (ADS)

    Kasner, James H.; Brower, Bernard V.

    2011-06-01

    In this paper we present formats and delivery methods of Large Volume Streaming Data (LVSD) systems. LVSD systems collect TBs of data per mission with aggregate camera sizes in the 100 Mpixel to several Gpixel range at temporal rates of 2 - 60 Hz. We present options and recommendations for the different stages of LVSD data collection and delivery, to include the raw (multi-camera) data, delivery of processed (stabilized mosaic) data, and delivery of user-defined region of interest windows. Many LVSD systems use JPEG 2000 for the compression of raw and processed data. We explore the use of the JPEG 2000 Interactive Protocol (JPIP) for interactive client/server delivery to thick-clients (desktops and laptops) and MPEG-2 and H.264 to handheld thin-clients (tablets, cell phones). We also explore the use of 3D JPEG 2000 compression, defined in ISO 15444-2, for storage and delivery as well. The delivery of raw, processed, and region of interest data requires different metadata delivery techniques and metadata content. Beyond the format and delivery of data and metadata we discuss the requirements for a client/server protocol that provides data discovery and retrieval. Finally, we look into the future as LVSD systems perform automated processing to produce "information" from the original data. This information may include tracks of moving targets, changes of the background, snap shots of targets, fusion of multiple sensors, and information about "events" that have happened.

  15. Mucoadhesive microparticulate drug delivery system of curcumin against Helicobacter pylori infection: Design, development and optimization

    PubMed Central

    Ali, Mohd Sajid; Pandit, Vinay; Jain, Mahendra; Dhar, Kanhiya Lal

    2014-01-01

    The purpose of the present research was to develop and characterize mucoadhesive microspheres of curcumin for the potential use of treating gastric adenocarcinoma, gastric and duodenal ulcer associated with Helicobacter pylori. Curcumin mucoadhesive microspheres were prepared using ethyl cellulose as a matrix and carbopol 934P as a mucoadhesive polymer by an emulsion-solvent evaporation technique. Response surface methodology was used for optimization of formulation using central composite design (CCD) for two factors at three levels each was employed to study the effect of independent variables, drug:polymer:polymer ratio (curcumin:ethylcellulose:carbopol 934P)(X1) and surfactant concentration (X2) on dependent variables, namely drug entrapment efficiency (DEE), percentage mucoadhesion (PM), in vitro drug release and particle size (PS). Optimized formulation was obtained using desirability approach of numerical optimization. The experimental values of DEE, PM, % release and PS after 8 h for the optimized formulation were found to be 50.256 ± 1.38%, 66.23%±0.06, 73.564 ± 1.32%, and 139.881 ± 2.56 μm, respectively, which were in close agreement with those predicted by the mathematical models. The drug release was also found to be slow and extended more than 8 h and release rates were fitted to the Power law equation and Higuchi model to compute the diffusional parameters. The prolonged stomach residence time of curcumin mucoadhesive microspheres might make a contribution to H. pylori complete eradication in combination with other antimicrobial agents. PMID:24696817

  16. Formulation and optimization of gastric floating drug delivery system using Central composite design and its biopharmaceutical evaluation.

    PubMed

    Meka, Venkata Srikanth; Thing, Lim Kee; Gorajana, Adinarayana; Kolapalli, Venkata Ramana-Murthy

    2015-07-01

    The present work investigates the formulation and biopharmaceutical estimation of gastric floating drug delivery system (GFDDS) of propranolol HCl using semi-synthetic polymer carboxymethyl ethyl cellulose (CMEC) and a synthetic polymer polyethylene oxide (PEO). A central composite design was applied for optimization of polymer quantity (CMEC or PEO) and sodium bicarbonate concentration as independent variables. The dependent variables evaluated were: % of drug release at 1 hr (D1hr), % drug release at 3 hr (D3hr) and time taken for 95% of drug release (t95). Numerical optimization and graphical optimization were conducted to optimize the response variables. All observed responses of statistically optimized formulations were in high treaty with predicted values. Accelerated stability studies were conducted on the optimized formulations at 40 ± 2°C/75% ± 5% RH and confirm that formulations were stable. Optimized formulations were evaluated for in vivo buoyancy characterization in human volunteers and were found buoyant in gastric fluid. Gastric residence time was enhanced in the fed but not the fasted state. The optimized formulations and marketed formulation were administered to healthy human volunteers and evaluated for pharmacokinetic parameters. Mean residence time (MRT) was prolonged and AUC levels were increased for both optimized floating tablets when compared with marketed product. High relative bioavailability obtained with optimized gastric floating tablets compared to commercial formulation, indicated the improvement of bioavailability. PMID:26142528

  17. Hydrogen storage and delivery system development

    SciTech Connect

    Handrock, J.L.; Wally, K.; Raber, T.N.

    1995-09-01

    Hydrogen storage and delivery is an important element in effective hydrogen utilization for energy applications and is an important part of the FY1994-1998 Hydrogen Program Implementation Plan. The purpose of this project is to develop a platform for the engineering evaluation of hydrogen storage and delivery systems with an added focus on lightweight hydride utilization. Hybrid vehicles represent the primary application area of interest, with secondary interests including such items as existing vehicles and stationary uses. The near term goal is the demonstration of an internal combustion engine/storage/delivery subsystem. The long term goal is optimization of storage technologies for both vehicular and industrial stationary uses. In this project an integrated approach is being used to couple system operating characteristics to hardware development. A model has been developed which integrates engine and storage material characteristics into the design of hydride storage and delivery systems. By specifying engine operating parameters, as well as a variety of storage/delivery design features, hydride bed sizing calculations are completed. The model allows engineering trade-off studies to be completed on various hydride material/delivery system configurations. A more generalized model is also being developed to allow the performance characteristics of various hydrogen storage and delivery systems to be compared (liquid, activated carbon, etc.). Many of the features of the hydride storage model are applicable to the development of this more generalized model.

  18. Transmucosal delivery systems for calcitonin: a review.

    PubMed

    Torres-Lugo, M; Peppas, N A

    2000-06-01

    The commercial availability of peptides and proteins and their advantages as therapeutic agents have been the basis for tremendous efforts in designing delivery systems for such agents. The protection of these agents from biological fluids and physiological interactions is crucial for the treatment efficacy. One such agent is salmon calcitonin, a 32 amino-acid polypeptide hormone used in the treatment of bone diseases such as Paget's disease, hypercalcemia and osteoporosis. Researchers have studied different routes to deliver salmon calcitonin more effectively, including nasal, oral, vaginal and rectal delivery. These systems are designed to protect the polypeptide from the biological barriers that each delivery route imposes. Oil-based and polymer-based delivery systems are discussed. PMID:10811300

  19. Radiation sterilization of new drug delivery systems

    PubMed Central

    Abuhanoğlu, Gürhan

    2014-01-01

    Radiation sterilization has now become a commonly used method for sterilization of several active ingredients in drugs or drug delivery systems containing these substances. In this context, many applications have been performed on the human products that are required to be sterile, as well as on pharmaceutical products prepared to be developed. The new drug delivery systems designed to deliver the medication to the target tissue or organ, such as microspheres, nanospheres, microemulsion, and liposomal systems, have been sterilized by gamma (γ) and beta (β) rays, and more recently, by e-beam sterilization. In this review, the sterilization of new drug delivery systems was discussed other than conventional drug delivery systems by γ irradiation. PMID:24936306

  20. The application of design principles to innovate clinical care delivery.

    PubMed

    Brennan, Michael D; Duncan, Alan K; Armbruster, Ryan R; Montori, Victor M; Feyereisn, Wayne L; LaRusso, Nicholas F

    2009-01-01

    Clinical research centers that support hypothesis-driven investigation have long been a feature of academic medical centers but facilities in which clinical care delivery can be systematically assessed and evaluated have heretofore been nonexistent. The Institute of Medicine report "Crossing the Quality Chasm" identified six core attributes of an ideal care delivery system that in turn relied heavily on system redesign. Although manufacturing and service industries have leveraged modern design principles in new product development, healthcare has lagged behind. In this article, we describe a methodology utilized by our facility to study the clinical care delivery system that incorporates modern design principles. PMID:19343895

  1. Electronic Nicotine Delivery Systems

    PubMed Central

    Adkison, Sarah E.; O’Connor, Richard J.; Bansal-Travers, Maansi; Hyland, Andrew; Borland, Ron; Yong, Hua-Hie; Cummings, K. Michael; McNeill, Ann; Thrasher, James F.; Hammond, David; Fong, Geoffrey T.

    2013-01-01

    Background Electronic nicotine delivery systems (ENDS) initially emerged in 2003 and have since become widely available globally, particularly over the Internet. Purpose Data on ENDS usage patterns are limited. The current paper examines patterns of ENDS awareness, use, and product-associated beliefs among current and former smokers in four countries. Methods Data come from Wave 8 of the International Tobacco Control Four-Country Survey, collected July 2010 to June 2011 and analyzed through June 2012. Respondents included 5939 current and former smokers in Canada (n=1581); the U.S. (n=1520); the United Kingdom (UK; n=1325); and Australia (n=1513). Results Overall, 46.6% were aware of ENDS (U.S.: 73%, UK: 54%, Canada: 40%, Australia: 20%); 7.6% had tried ENDS (16% of those aware of ENDS); and 2.9% were current users (39% of triers). Awareness of ENDS was higher among younger, non-minority smokers with higher incomes who were heavier smokers. Prevalence of trying ENDS was higher among younger, nondaily smokers with a high income and among those who perceived ENDS as less harmful than traditional cigarettes. Current use was higher among both nondaily and heavy (≥20 cigarettes per day) smokers. In all, 79.8% reported using ENDS because they were considered less harmful than traditional cigarettes; 75.4% stated that they used ENDS to help them reduce their smoking; and 85.1% reported using ENDS to help them quit smoking. Conclusions Awareness of ENDS is high, especially in countries where they are legal (i.e., the U.S. and UK). Because trial was associated with nondaily smoking and a desire to quit smoking, ENDS may have potential to serve as a cessation aid. PMID:23415116

  2. Transcutaneous antigen delivery system

    PubMed Central

    Lee, Mi-Young; Shin, Meong-Cheol; Yang, Victor C.

    2013-01-01

    Transcutaneous immunization refers to the topical application of antigens onto the epidermis. Transcutaneous immunization targeting the Langerhans cells of the skin has received much attention due to its safe, needle-free, and noninvasive antigen delivery. The skin has important immunological functions with unique roles for antigen-presenting cells such as epidermal Langerhans cells and dermal dendritic cells. In recent years, novel vaccine delivery strategies have continually been developed; however, transcutaneous immunization has not yet been fully exploited due to the penetration barrier represented by the stratum corneum, which inhibits the transport of antigens and adjuvants. Herein we review recent achievements in transcutaneous immunization, focusing on the various strategies for the enhancement of antigen delivery and vaccination efficacy. [BMB Reports 2013; 46(1): 17-24] PMID:23351379

  3. Radiation delivery system and method

    DOEpatents

    Sorensen, Scott A.; Robison, Thomas W.; Taylor, Craig M. V.

    2002-01-01

    A radiation delivery system and method are described. The system includes a treatment configuration such as a stent, balloon catheter, wire, ribbon, or the like, a portion of which is covered with a gold layer. Chemisorbed to the gold layer is a radiation-emitting self-assembled monolayer or a radiation-emitting polymer. The radiation delivery system is compatible with medical catheter-based technologies to provide a therapeutic dose of radiation to a lesion following an angioplasty procedure.

  4. Fluid delivery control system

    SciTech Connect

    Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad

    2006-06-06

    A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.

  5. Formulation considerations in the design of topical, polymeric film-forming systems for sustained drug delivery to the skin.

    PubMed

    Frederiksen, Kit; Guy, Richard H; Petersson, Karsten

    2015-04-01

    Polymeric film-forming systems (FFSs) are potential drug delivery systems for topical application to the skin. The FFSs form thin and transparent polymeric films in situ upon solvent evaporation. Their application convenience and cosmetic attributes, superior to conventional semi-solids, may offer improved patient compliance. This study represents the first phase of an investigation into the use of FFSs for prolonged dermal drug delivery. FFS formulations were distinguished based on their ability to sustain the release of betamethasone 17-valerate (BMV) in vitro over 72 h. The effect of film-forming polymer (hydrophilic: hydroxypropyl cellulose (Klucel™ LF); hydrophobic: polymethacrylate copolymers (Eudragit® NE and Eudragit® RS), and polyacrylate copolymer (Dermacryl® 79) was first determined, and then the impact of incorporation of plasticisers (triethyl citrate, tributyl citrate, and dibutyl sebacate) was examined. The Klucel film released a significantly higher amount of BMV than the hydrophobic FFS, 42 versus 4 μg/cm(2), respectively. The release was increased when a plasticiser was incorporated, and with higher enhancement ratios achieved with the more lipophilic plasticisers. In conclusion, the results show that FFSs can sustain drug release (hence representing useful systems for prolonged dermal therapy) and emphasise the importance of the formulation on drug delivery, with the type of polymer being of greatest significance. PMID:25595740

  6. Adenosine-Associated Delivery Systems

    PubMed Central

    Kazemzadeh-Narbat, Mehdi; Annabi, Nasim; Tamayol, Ali; Oklu, Rahmi; Ghanem, Amyl; Khademhosseini, Ali

    2016-01-01

    Adenosine is a naturally occurring purine nucleoside in every cell. Many critical treatments such as modulating irregular heartbeat (arrhythmias), regulation of central nervous system (CNS) activity, and inhibiting seizural episodes can be carried out using adenosine. Despite the significant potential therapeutic impact of adenosine and its derivatives, the severe side effects caused by their systemic administration have significantly limited their clinical use. In addition, due to adenosine’s extremely short half-life in human blood (less than 10 s), there is an unmet need for sustained delivery systems to enhance efficacy and reduce side effects. In this paper, various adenosine delivery techniques, including encapsulation into biodegradable polymers, cell-based delivery, implantable biomaterials, and mechanical-based delivery systems, are critically reviewed and the existing challenges are highlighted. PMID:26453156

  7. Viral and nonviral delivery systems for gene delivery.

    PubMed

    Nayerossadat, Nouri; Maedeh, Talebi; Ali, Palizban Abas

    2012-01-01

    Gene therapy is the process of introducing foreign genomic materials into host cells to elicit a therapeutic benefit. Although initially the main focus of gene therapy was on special genetic disorders, now diverse diseases with different patterns of inheritance and acquired diseases are targets of gene therapy. There are 2 major categories of gene therapy, including germline gene therapy and somatic gene therapy. Although germline gene therapy may have great potential, because it is currently ethically forbidden, it cannot be used; however, to date human gene therapy has been limited to somatic cells. Although numerous viral and nonviral gene delivery systems have been developed in the last 3 decades, no delivery system has been designed that can be applied in gene therapy of all kinds of cell types in vitro and in vivo with no limitation and side effects. In this review we explain about the history of gene therapy, all types of gene delivery systems for germline (nuclei, egg cells, embryonic stem cells, pronuclear, microinjection, sperm cells) and somatic cells by viral [retroviral, adenoviral, adeno association, helper-dependent adenoviral systems, hybrid adenoviral systems, herpes simplex, pox virus, lentivirus, Epstein-Barr virus)] and nonviral systems (physical: Naked DNA, DNA bombardant, electroporation, hydrodynamic, ultrasound, magnetofection) and (chemical: Cationic lipids, different cationic polymers, lipid polymers). In addition to the above-mentioned, advantages, disadvantages, and practical use of each system are discussed. PMID:23210086

  8. Gantries and dose delivery systems

    NASA Astrophysics Data System (ADS)

    Meer, David; Psoroulas, Serena

    2015-04-01

    Particle therapy is a field in remarkable development, with the goal of increasing the number of indications which could benefit from such treatments and the access to the therapy. The therapeutic usage of a particle beam defines the technical requirements of all the elements of the therapy chain: we summarize the main characteristics of accelerators, the beam line, the treatment room, the integrated therapy and imaging systems used in particle therapy. Aiming at a higher flexibility in the choice of treatments, an increasing number of centers around the world have chosen to equip their treatment rooms with gantries, rotating beam line structures that allow a complete flexibility in the choice of the treatment angle. We review the current designs. A particle therapy gantry though is a quite expensive structure, and future development will increasingly consider reducing the cost and the footprint. Increasing the number of indications also means development in the delivery techniques and solving some of the issues which traditionally affected particle therapy, for example the precision of the delivery in presence of motion and the large penumbras for low depths. We show the current strategies in these fields, focusing on pencil beam scanning (PBS), and give some hints about future developments.

  9. Development of insulin delivery systems.

    PubMed

    Siddiqui, N I; Siddiqui, Ni; Rahman, S; Nessa, A

    2008-01-01

    Delivery system of insulin is vital for its acceptance and adherence to therapy for achieving the glycemic targets. Enormous developments have occurred in the delivery system of insulin during the last twenty years and each improvement was aimed at two common goals: patients convenience and better glycemic control. Till to date, the various insulin delivery systems are: syringes/vials, injection aids, jet injectors, transmucosal delivery, transdermal delivery, external insulin infusion pump, implantable insulin pumps, insulin pens and insulin inhalers. Syringe/vial is the oldest and conventional method, still widely used and relatively cheaper. Modern plastic syringes are disposable, light weight with microfine needle for patients convenience and comfort. Oral route could be the most acceptable and viable, if the barriers can be overcome and under extensive trial. Insulin pen device is an important milestone in the delivery system of insulin as it is convenient, discrete, painless, attractive, portable with flexible life style and improved quality of life. More than 80% of European diabetic patients are using insulin pen. Future digital pen will have better memory option, blood glucose monitoring system, insulin dose calculator etc. Insulin infusion pump is a good option for the children, busy patients with flexible lifestyle and those who want to avoid multiple daily injections. Pulmonary route of insulin delivery is a promising, effective, non-invasive and acceptable alternative method. Exubera, the world first insulin inhaler was approved by FDA in 28 January 2006. But due to certain limitations, it has been withdrawn from the market in October 2007. The main concern of inhaled insulin are: long term pulmonary safety issues, cost effectiveness and user friendly device. In future, more acceptable and cost effective insulin inhaler will be introduced. Newer avenues are under extensive trial for better future insulin delivery systems. PMID:18285745

  10. Nanoparticulate systems for polynucleotide delivery

    PubMed Central

    Basarkar, Ashwin; Singh, Jagdish

    2007-01-01

    Nanotechnology has tremendously influenced gene therapy research in recent years. Nanometer-size systems have been extensively investigated for delivering genes at both local and systemic levels. These systems offer several advantages in terms of tissue penetrability, cellular uptake, systemic circulation, and cell targeting as compared to larger systems. They can protect the polynucleotide from a variety of degradative and destabilizing factors and enhance delivery efficiency to the cells. A variety of polymeric and non-polymeric nanoparticles have been investigated in an effort to maximize the delivery efficiency while minimizing the toxic effects. This article provides a review on the most commonly used nanoparticulate systems for gene delivery. We have discussed frequently used polymers, such as, polyethyleneimine, poly (lactide-co-glycolide), chitosan, as well as non-polymeric materials such as cationic lipids and metallic nanoparticles. The advantages and limitations of each system have been elaborated. PMID:18019834

  11. Novel drug delivery systems for glaucoma

    PubMed Central

    Lavik, E; Kuehn, M H; Kwon, Y H

    2011-01-01

    Reduction of intraocular pressure (IOP) by pharmaceutical or surgical means has long been the standard treatment for glaucoma. A number of excellent drugs are available that are effective in reducing IOP. These drugs are typically applied as eye drops. However, patient adherence can be poor, thus reducing the clinical efficacy of the drugs. Several novel delivery systems designed to address the issue of adherence and to ensure consistent reduction of IOP are currently under development. These delivery systems include contact lenses-releasing glaucoma medications, injectables such as biodegradable micro- and nanoparticles, and surgically implanted systems. These new technologies are aimed at increasing clinical efficacy by offering multiple delivery options and are capable of managing IOP for several months. There is also a desire to have complementary neuroprotective approaches for those who continue to show progression, despite IOP reduction. Many potential neuroprotective agents are not suitable for traditional oral or drop formulations. Their potential is dependent on developing suitable delivery systems that can provide the drugs in a sustained, local manner to the retina and optic nerve. Drug delivery systems have the potential to improve patient adherence, reduce side effects, increase efficacy, and ultimately, preserve sight for glaucoma patients. In this review, we discuss benefits and limitations of the current systems of delivery and application, as well as those on the horizon. PMID:21475311

  12. Novel central nervous system drug delivery systems.

    PubMed

    Stockwell, Jocelyn; Abdi, Nabiha; Lu, Xiaofan; Maheshwari, Oshin; Taghibiglou, Changiz

    2014-05-01

    For decades, biomedical and pharmaceutical researchers have worked to devise new and more effective therapeutics to treat diseases affecting the central nervous system. The blood-brain barrier effectively protects the brain, but poses a profound challenge to drug delivery across this barrier. Many traditional drugs cannot cross the blood-brain barrier in appreciable concentrations, with less than 1% of most drugs reaching the central nervous system, leading to a lack of available treatments for many central nervous system diseases, such as stroke, neurodegenerative disorders, and brain tumors. Due to the ineffective nature of most treatments for central nervous system disorders, the development of novel drug delivery systems is an area of great interest and active research. Multiple novel strategies show promise for effective central nervous system drug delivery, giving potential for more effective and safer therapies in the future. This review outlines several novel drug delivery techniques, including intranasal drug delivery, nanoparticles, drug modifications, convection-enhanced infusion, and ultrasound-mediated drug delivery. It also assesses possible clinical applications, limitations, and examples of current clinical and preclinical research for each of these drug delivery approaches. Improved central nervous system drug delivery is extremely important and will allow for improved treatment of central nervous system diseases, causing improved therapies for those who are affected by central nervous system diseases. PMID:24325540

  13. Collagen interactions: Drug design and delivery.

    PubMed

    An, Bo; Lin, Yu-Shan; Brodsky, Barbara

    2016-02-01

    Collagen is a major component in a wide range of drug delivery systems and biomaterial applications. Its basic physical and structural properties, together with its low immunogenicity and natural turnover, are keys to its biocompatibility and effectiveness. In addition to its material properties, the collagen triple-helix interacts with a large number of molecules that trigger biological events. Collagen interactions with cell surface receptors regulate many cellular processes, while interactions with other ECM components are critical for matrix structure and remodeling. Collagen also interacts with enzymes involved in its biosynthesis and degradation, including matrix metalloproteinases. Over the past decade, much information has been gained about the nature and specificity of collagen interactions with its partners. These studies have defined collagen sequences responsible for binding and the high-resolution structures of triple-helical peptides bound to its natural binding partners. Strategies to target collagen interactions are already being developed, including the use of monoclonal antibodies to interfere with collagen fibril formation and the use of triple-helical peptides to direct liposomes to melanoma cells. The molecular information about collagen interactions will further serve as a foundation for computational studies to design small molecules that can interfere with specific interactions or target tumor cells. Intelligent control of collagen biological interactions within a material context will expand the effectiveness of collagen-based drug delivery. PMID:26631222

  14. Design and evaluation of a gastroretentive drug delivery system for metformin HCl using synthetic and semi-synthetic polymers.

    PubMed

    Meka, Venkata Srikanth; Gorajana, Adinaravyana; Dharmanlingam, Senthil Rajan; Kolapalli, Venkata Ramana Murthy

    2013-12-01

    The aim of the present research was to prepare and evaluate a gastroretentive drug delivery system for metformin HCl, using synthetic and semi-synthetic polymers. The floating approach was applied for preparing gastroretentive tablets (GRT) and these tablets were manufactured by the direct compression method. The drug delivery system comprises of synthetic and semi-synthetic polymers such as polyethylene oxide and Carboxymethyl ethyl cellulose (CMEC) as release-retarding polymers. GRT were evaluated for physico-chemical properties like weight variation, hardness, assay friability, in vitro floating behaviour, swelling studies, in vitro dissolution studies and rate order kinetics. Based upon the drug release and floating properties, two formulations (MP04 & MC03) were selected as optimized formulations. The optimized formulations MP04 and MC03 followed zero order rate kinetics, with non-Fickian diffusion and first order rate kinetics with erosion mechanism, respectively. The optimized formulation was characterised with FTIR studies and it was observed that there was no interaction between the drug and polymers. PMID:24502177

  15. Design and evaluation of hydrophobic coated buoyant core as floating drug delivery system for sustained release of cisapride

    PubMed Central

    Jacob, Shery; Nair, Anroop B; Patil, Pandurang N

    2010-01-01

    An inert hydrophobic buoyant coated–core was developed as floating drug delivery system (FDDS) for sustained release of cisapride using direct compression technology. Core contained low density, porous ethyl cellulose, which was coated with an impermeable, insoluble hydrophobic coating polymer such as rosin. It was further seal coated with low viscosity hydroxypropyl methyl cellulose (HPMC E15) to minimize moisture permeation and better adhesion with an outer drug layer. It was found that stable buoyant core was sufficient to float the tablet more than 8 h without the aid of sodium bicarbonate and citric acid. Sustained release of cisapride was achieved with HPMC K4M in the outer drug layer. The floating lag time required for these novel FDDS was found to be zero, however it is likely that the porosity or density of the core is critical for floatability of these tablets. The in vitro release pattern of these tablets in simulated gastric fluid showed the constant and controlled release for prolonged time. It can be concluded that the hydrophobic coated buoyant core could be used as FDDS for gastroretentive delivery system of cisapride or other suitable drugs. PMID:24825997

  16. Design of lipid-based delivery systems for improving lymphatic transport and bioavailability of delta-tocopherol and nobiletin

    NASA Astrophysics Data System (ADS)

    Xia, Chunxin

    Lymphatic drug transport can confer bioavailability advantage by avoiding the first-pass metabolism normally observed in the portal vein hepatic route. It was reported that long chain lipid-based delivery systems can stimulate the formation of chylomicron and thus promote the lymphatic transport of drugs. In this study, a novel delta-tocopherol (delta-T) loaded Solid Lipid Nanoparticle (SLN) system was developed to investigate its effect on promoting the lymphatic transport of delta-T. The delta-T SLN was prepared with hot melt emulsification method by using glyceryl behenate (compritol RTM888) as the lipid phase and lecithin (PC75) as the emulsifier. Formula configuration, processing condition and loading capacity were carefully optimized. Physicochemical properties (particle size, surface charge, morphology) were also characterized. Moreover, excellent stability of the developed delta-T SLN in the gastrointestinal environment was observed by using an in vitro digestion model. Further investigations of the SLN in stimulating delta-T lymphatic transport were performed on mice without cannulation. Compared with the control group (delta-T corn oil dispersion), much lower delta-T levels in both blood and liver indicated reduced portal vein and hepatic transport of delta-T in the form of SLN. On the other hand, significantly higher concentrations of delta-T were observed in thymus, a major lymphatic tissue, indicating improved lymphatic transport of delta-T with the SLN delivery system. Finally, the far less excreted delta-T level in feces further confirmed improved lymphatic transport and overall bioavailability of delta-T by using SLN system. Nobiletin (NOB), one of most abundant polymethoxyflavones (PMFs) found in Citrus genus, has a low solubility in both water and oil at ambient temperatures. Thus it tends to form crystals when the loading exceeds its saturation level in the carrier system. This character greatly impaired its bioavailability and application. To

  17. Delivery System, 2003-2004.

    ERIC Educational Resources Information Center

    Office of Federal Student Aid (ED), Washington, DC.

    This workshop guide for financial aid administrators provides training in the federal student financial aid delivery system. An introduction enables the participant to share some information about his or her responsibilities and to reflect on the relevance of the training to the job. Session 1, "Application Systems," identifies methods of applying…

  18. Waste Feed Delivery Transfer System Analysis

    SciTech Connect

    JULYK, L.J.

    2000-05-05

    This document provides a documented basis for the required design pressure rating and pump pressure capacity of the Hanford Site waste-transfer system in support of the waste feed delivery to the privatization contractor for vitrification. The scope of the analysis includes the 200 East Area double-shell tank waste transfer pipeline system and the associated transfer system pumps for a11 Phase 1B and Phase 2 waste transfers from AN, AP, AW, AY, and A2 Tank Farms.

  19. Novel Solid Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) for Oral Delivery of Olmesartan Medoxomil: Design, Formulation, Pharmacokinetic and Bioavailability Evaluation.

    PubMed

    Nasr, Ali; Gardouh, Ahmed; Ghorab, Mamdouh

    2016-01-01

    The main purpose of this study was to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) of Olmesartan (OLM) for enhancement of its solubility and dissolution rate. In this study, liquid SNEDDS containing Olmesartan was formulated and further developed into a solid form by the spray drying technique using Aerosil 200 as a solid carrier. Based on the preliminary screening of different unloaded SNEDDS formulae, eight formulae of OLM loaded SNEEDS were prepared using Capryol 90, Cremophor RH40 and Transcutol HP as oil, surfactant and cosurfactant, respectively. Results showed that the mean droplet size of all reconstituted SNEDDS was found to be in the nanometric range (14.91-22.97 nm) with optimum PDI values (0.036-0.241). All formulae also showed rapid emulsification time (15.46 ± 1.34-24.17 ± 1.47 s), good optical clarity (98.33% ± 0.16%-99.87% ± 0.31%) and high drug loading efficiency (96.41% ± 1.20%-99.65% ± 1.11%). TEM analysis revealed the formation of spherical and homogeneous droplets with a size smaller than 50 nm. In vitro release of OLM from SNEDDS formulae showed that more than 90% of OLM released in approximately 90 min. Optimized SNEDDS formulae were selected to be developed into S-SNEDDS using the spray drying technique. The prepared S-SNEDDS formulae were evaluated for flow properties, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), reconstitution properties, drug content and in vitro dissolution study. It was found that S-SNEDDS formulae showed good flow properties and high drug content. Reconstitution properties of S-SNEDDS showed spontaneous self-nanoemulsification and no sign of phase separation. DSC thermograms revealed that OLM was in solubilized form and FTIR supported these findings. SEM photographs showed smooth uniform surface of S-SNEDDS with less aggregation. Results of the in vitro drug release showed that there was great enhancement in the dissolution rate of OLM. To clarify the

  20. Design, development and optimization of self-microemulsifying drug delivery system of an anti-obesity drug.

    PubMed

    Desai, Jagruti; Khatri, Nirav; Chauhan, Sachin; Seth, Avinash

    2012-03-01

    The aim of the present work was to formulate a self-microemulsifying drug delivery system (SMEDDS) containing orlistat. The oil, surfactant and co-surfactant were decided based on the solubility studies. Pseudoternary phase diagrams were plotted, microemulsification area was determined and different formulations were prepared. Particle size, zeta potential, dispersibility test and thermodynamic stability studies were measured. In-vitro dissolution test of thermodynamically stable formulations OS-B and OS-C were carried and results were compared with those of plain drug and suspension formulation. Stability studies performed indicated that formulation OS-C remained stable over 12 months period. Thus this investigation concluded that hydrophobic drugs like orlistat can be delivered effectively through the formulation of SMEDDS. PMID:23066191

  1. Design, development and optimization of self-microemulsifying drug delivery system of an anti-obesity drug

    PubMed Central

    Desai, Jagruti; Khatri, Nirav; Chauhan, Sachin; Seth, Avinash

    2012-01-01

    The aim of the present work was to formulate a self-microemulsifying drug delivery system (SMEDDS) containing orlistat. The oil, surfactant and co-surfactant were decided based on the solubility studies. Pseudoternary phase diagrams were plotted, microemulsification area was determined and different formulations were prepared. Particle size, zeta potential, dispersibility test and thermodynamic stability studies were measured. In-vitro dissolution test of thermodynamically stable formulations OS-B and OS-C were carried and results were compared with those of plain drug and suspension formulation. Stability studies performed indicated that formulation OS-C remained stable over 12 months period. Thus this investigation concluded that hydrophobic drugs like orlistat can be delivered effectively through the formulation of SMEDDS. PMID:23066191

  2. Nanofibers based antibacterial drug design, delivery and applications.

    PubMed

    Ulubayram, Kezban; Calamak, Semih; Shahbazi, Reza; Eroglu, Ipek

    2015-01-01

    Infections caused by microorganisms like bacteria, fungi, etc. are the main obstacle in healing processes. Conventional antibacterial administration routes can be listed as oral, intravenous/intramuscular, topical and inhalation. These kinds of drug administrations are faced with critical vital issues such as; more rapid delivery of the drug than intended which can result in bacterial resistance, dose related systemic toxicity, tissue irritation and finally delayed healing process that need to be tackled. Recently, studies have been focused on new drug delivery systems, overcoming resistance and toxicological problems and finally localizing the molecules at the site of action in a proper dose. In this regard, many nanotechnological approaches such as nanoparticulate therapeutic systems have been developed to address accompanying problems mentioned above. Among them, drug loaded electrospun nanofibers propose main advantages like controlled drug delivery, high drug loading capacity, high encapsulation efficiency, simultaneous delivery of multiple drugs, ease of production and cost effectiveness for pharmaceutical and biomedical applications. Therefore, some particular attention has been devoted to the design of electrospun nanofibers as promising antibacterial drug carrier systems. A variety of antibacterials e.g., biocides, antibiotics, quaternary ammonium salts, triclosan, metallic nanoparticles (silver, titanium dioxide, and zinc oxide) and antibacterial polymers (chitosan, polyethyleneimine, etc.) have been impregnated by various techniques into nanofibers that exhibit strong antibacterial activity in standard assays. This review highlights the design and delivery of antibacterial drug loaded nanofibers with particular focus on their function in the fields of drug delivery, wound healing, tissue engineering, cosmetics and other biomedical applications. PMID:25732666

  3. Starch Applications for Delivery Systems

    NASA Astrophysics Data System (ADS)

    Li, Jason

    2013-03-01

    Starch is one of the most abundant and economical renewable biopolymers in nature. Starch molecules are high molecular weight polymers of D-glucose linked by α-(1,4) and α-(1,6) glycosidic bonds, forming linear (amylose) and branched (amylopectin) structures. Octenyl succinic anhydride modified starches (OSA-starch) are designed by carefully choosing a proper starch source, path and degree of modification. This enables emulsion and micro-encapsulation delivery systems for oil based flavors, micronutrients, fragrance, and pharmaceutical actives. A large percentage of flavors are encapsulated by spray drying in today's industry due to its high throughput. However, spray drying encapsulation faces constant challenges with retention of volatile compounds, oxidation of sensitive compound, and manufacturing yield. Specialty OSA-starches were developed suitable for the complex dynamics in spray drying and to provide high encapsulation efficiency and high microcapsule quality. The OSA starch surface activity, low viscosity and film forming capability contribute to high volatile retention and low active oxidation. OSA starches exhibit superior performance, especially in high solids and high oil load encapsulations compared with other hydrocolloids. The submission is based on research and development of Ingredion

  4. Sterile Product Packaging and Delivery Systems.

    PubMed

    Akers, Michael J

    2015-01-01

    Both conventional and more advanced product container and delivery systems are the focus of this brief article. Six different product container systems will be discussed, plus advances in primary packaging for special delivery systems and needle technology. PMID:26891564

  5. Design and evaluation of polymeric coated minitablets as multiple unit gastroretentive floating drug delivery systems for furosemide.

    PubMed

    Meka, Lingam; Kesavan, Bhaskar; Kalamata, Venkatasimhadri Naidu; Eaga, Chandra Mohan; Bandari, Suresh; Vobalaboina, Venkateswarlu; Yamsani, Madhusudan Rao

    2009-06-01

    A gastro retentive floating drug delivery system with multiple-unit minitablets based on gas formation technique was developed for furosemide. The system consists of core units (solid dispersion of furosemide:povidone and other excipients), prepared by direct compression process, which are coated with two successive layers, one of which is an effervescent (sodium bicarbonate) layer and other one an outer polymeric layer of polymethacrylates. The formulations were evaluated for pharmacopoeial quality control tests and all the physical parameters evaluated were within the acceptable limits. Only the system using Eudragit RL30D and combination of them as polymeric layer could float within acceptable time. The time to float decreased as amount of the effervescent agent increased and, when the coating level of polymeric layer decreased. The drug release was controlled and linear with the square root of time. By increasing coating level of polymeric layer decreased the drug release. The rapid floating and the controlled release properties were achieved in this present study. The stability samples showed no significant change in dissolution profiles (f(2) = 81). The in vivo gastric residence time was examined by radiograms and it was observed that the units remained in the stomach for about 6 h. PMID:19009598

  6. Delivery systems for intradermal vaccination.

    PubMed

    Kim, Y C; Jarrahian, C; Zehrung, D; Mitragotri, S; Prausnitz, M R

    2012-01-01

    Intradermal (ID) vaccination can offer improved immunity and simpler logistics of delivery, but its use in medicine is limited by the need for simple, reliable methods of ID delivery. ID injection by the Mantoux technique requires special training and may not reliably target skin, but is nonetheless used currently for BCG and rabies vaccination. Scarification using a bifurcated needle was extensively used for smallpox eradication, but provides variable and inefficient delivery into the skin. Recently, ID vaccination has been simplified by introduction of a simple-to-use hollow microneedle that has been approved for ID injection of influenza vaccine in Europe. Various designs of hollow microneedles have been studied preclinically and in humans. Vaccines can also be injected into skin using needle-free devices, such as jet injection, which is receiving renewed clinical attention for ID vaccination. Projectile delivery using powder and gold particles (i.e., gene gun) have also been used clinically for ID vaccination. Building off the scarification approach, a number of preclinical studies have examined solid microneedle patches for use with vaccine coated onto metal microneedles, encapsulated within dissolving microneedles or added topically to skin after microneedle pretreatment, as well as adapting tattoo guns for ID vaccination. Finally, technologies designed to increase skin permeability in combination with a vaccine patch have been studied through the use of skin abrasion, ultrasound, electroporation, chemical enhancers, and thermal ablation. The prospects for bringing ID vaccination into more widespread clinical practice are encouraging, given the large number of technologies for ID delivery under development. PMID:21472533

  7. Drug Delivery Systems: Entering the Mainstream

    NASA Astrophysics Data System (ADS)

    Allen, Theresa M.; Cullis, Pieter R.

    2004-03-01

    Drug delivery systems (DDS) such as lipid- or polymer-based nanoparticles can be designed to improve the pharmacological and therapeutic properties of drugs administered parenterally. Many of the early problems that hindered the clinical applications of particulate DDS have been overcome, with several DDS formulations of anticancer and antifungal drugs now approved for clinical use. Furthermore, there is considerable interest in exploiting the advantages of DDS for in vivo delivery of new drugs derived from proteomics or genomics research and for their use in ligand-targeted therapeutics.

  8. Insulin Delivery System

    NASA Technical Reports Server (NTRS)

    1988-01-01

    When Programmable Implantable Medication System (PIMS) is implanted in human body, it delivers precise programmed amounts of insulin over long periods of time. Mini-Med Technologies has been refining the Technologies since initial development at APL. The size of a hockey puck, and encased in titanium shell, PIMS holds about 2 1/2 teaspoons of insulin at a programmed basal rate. If a change in measured blood sugar level dictates a different dose, the patient can vary the amount of insulin delivered by holding a small radio transceiver over the implanted system and dialing in a specific program held in the PIMS computer memory. Insulin refills are accomplished approximately 4 times a year by hypodermic needle.

  9. [Progression of drug delivery system for glaucoma].

    PubMed

    Xu, Yan; Lyu, Liu

    2014-12-01

    Reduction of intraocular pressure (IOP) by drugs is a major treatment for glaucoma. Clinically, diverse antiglaucoma drugs take effect to decrease the IOP through different mechanisms.However, due to limitations of traditional form of eye drops, the bioavailability of the drug and the patient compliance is lowered, the clinical efficacy is not good and also some toxic and side-effects come out.Otherwise, traditional medication is not suitable for neuroprotective drugs to work on both retina and optic nerve. Drug delivery system has the potential to improve the bioavailability of the drug, prolong the time of drug action, decrease the dosage and frequency of drugs, reduce the side-effects, and improve the patient compliance and efficacy.It is one of the most important studies in glaucoma medication development because it is valuable for patients' neuroprotection.Nowadays, several novel delivery systems have been designed. This review will focus on the progressions of some of the sustained-release antiglaucoma eye drops, polymeric gels, colloidal systems, membrane-controlled drug delivery system, ocular implants, and transscleral drug delivery systems. PMID:25619186

  10. Mucoadhesive vaginal drug delivery systems.

    PubMed

    Acartürk, Füsun

    2009-11-01

    Vaginal delivery is an important route of drug administration for both local and systemic diseases. The vaginal route has some advantages due to its large surface area, rich blood supply, avoidance of the first-pass effect, relatively high permeability to many drugs and self-insertion. The traditional commercial preparations, such as creams, foams, gels, irrigations and tablets, are known to reside in the vaginal cavity for a relatively short period of time owing to the self-cleaning action of the vaginal tract, and often require multiple daily doses to ensure the desired therapeutic effect. The vaginal route appears to be highly appropriate for bioadhesive drug delivery systems in order to retain drugs for treating largely local conditions, or for use in contraception. In particular, protection against sexually-transmitted diseases is critical. To prolong the residence time in the vaginal cavity, bioadhesive therapeutic systems have been developed in the form of semi-solid and solid dosage forms. The most commonly used mucoadhesive polymers that are capable of forming hydrogels are synthetic polyacrylates, polycarbophil, chitosan, cellulose derivatives (hydroxyethycellulose, hydroxy-propylcellulose and hydroxypropylmethylcellulose), hyaluronic acid derivatives, pectin, tragacanth, carrageenan and sodium alginate. The present article is a comprehensive review of the patents related to mucoadhesive vaginal drug delivery systems. PMID:19925443

  11. Spectroscopic analysis of aluminum chloride phthalocyanine in binary water/ethanol systems for the design of a new drug delivery system for photodynamic therapy cancer treatment

    NASA Astrophysics Data System (ADS)

    Jayme, Cristiano Ceron; Calori, Italo Rodrigo; Tedesco, Antonio Claudio

    2016-01-01

    This study evaluated the behavior of aluminum chloride phthalocyanine in a binary water/ethanol mixture using electronic absorption spectroscopy and static and time-resolved fluorescence spectroscopy. The electronic absorption spectra, resonance light scattering and fluorescence quenching of aluminum chloride phthalocyanine in water/ethanol mixtures were studied at several concentrations. The electronic absorption spectra and fluorescence quenching changed significantly at approximately 50% water (v/v). Below 50% water, the dimerization constant values were negative (- 2609.2 M- 1 and - 506.5 M- 1 at 30% and 40% of water, respectively), indicating that the formation of aggregates under these conditions is not favored. However, at 50% water, the dimerization constant value was estimated to be 559.7 M- 1, which indicates the presence of dimers. Above 60% water, the aggregation process was responsible for the balance between large complexes (such as trimers, tetramers or oligomers) formed in the medium under these conditions. The appearance of new absorption bands at 387 nm and 802 nm and their bathochromic shift relative to the monomer bands suggested that some J-type aggregates form. These results are relevant to understanding the behavior and use of aluminum chloride phthalocyanine in the design of new drug delivery systems for clinical application in photodynamic therapy as a new approach to treat skin cancer.

  12. Hydrogen storage and delivery system development: Fabrication

    SciTech Connect

    Handrock, J.L.; Malinowski, M.E.; Wally, K.

    1996-10-01

    Hydrogen storage and delivery is an important element in effective hydrogen utilization for energy applications and is an important part of the FY1994-1998 Hydrogen Program Implementation Plan. This project is part of the Field Work Proposal entitled Hydrogen Utilization in Internal Combustion Engines (ICE). The goal of the Hydrogen Storage and Delivery System Development Project is to expand the state-of-the-art of hydrogen storage and delivery system design and development. At the foundation of this activity is the development of both analytical and experimental evaluation platforms. These tools provide the basis for an integrated approach for coupling hydrogen storage and delivery technology to the operating characteristics of potential hydrogen energy use applications. Analytical models have been developed for internal combustion engine (ICE) hybrid and fuel cell driven vehicles. The dependence of hydride storage system weight and energy use efficiency on engine brake efficiency and exhaust temperature for ICE hybrid vehicle applications is examined. Results show that while storage system weight decreases with increasing engine brake efficiency energy use efficiency remains relatively unchanged. The development, capability, and use of a newly developed fuel cell vehicle hydride storage system model will also be discussed. As an example of model use power distribution and control for a simulated driving cycle is presented. An experimental test facility, the Hydride Bed Testing Laboratory (HBTL) has been designed and fabricated. The development of this facility and its use in storage system development will be reviewed. These two capabilities (analytical and experimental) form the basis of an integrated approach to storage system design and development. The initial focus of these activities has been on hydride utilization for vehicular applications.

  13. A three-drug nanoscale drug delivery system designed for preferential lymphatic uptake for the treatment of metastatic melanoma.

    PubMed

    Doddapaneni, Bhuvana S; Kyryachenko, Sergiy; Chagani, Sharmeen E; Alany, Raid G; Rao, Deepa A; Indra, Arup K; Alani, Adam W G

    2015-12-28

    Metastatic melanoma has a high mortality rate due to lymphatic progression of the disease. Current treatment is surgery followed by radiation and intravenous chemotherapy. However, drawbacks for current chemotherapeutics lie in the fact that they develop resistance and do not achieve therapeutic concentrations in the lymphatic system. We hypothesize that a three-drug nanoscale drug delivery system, tailored for lymphatic uptake, administered subcutaneously, will have decreased drug resistance and therefore offer better therapeutic outcomes. We prepared and characterized nanoparticles (NPs) with docetaxel, everolimus, and LY294002 in polyethyleneglycol-block-poly(ε-caprolactone) (PEG-PCL) polymer with different charge distributions by modifying the ratio of anionic and neutral end groups on the PEG block. These NPs are similarly sized (~48 nm), with neutral, partially charged, or fully charged surface. The NPs are able to load ~2mg/mL of each drug and are stable for 24h. The NPs are assessed for safety and efficacy in two transgenic metastatic melanoma mouse models. All the NPs were safe in both models based on general appearance, weight changes, death, and blood biochemical analyses. The partially charged NPs are most effective in decreasing the number of melanocytes at both the proximal (sentinel) lymph node (LN) and the distal LN from the injection site. The neutral NPs are efficacious at the proximal LN, while the fully charged NPs have no effect on either LNs. Thus, our data indicates that the NP surface charge and lymphatic efficacy are closely tied to each other and the partially charged NPs have the highest potential in treating metastatic melanoma. PMID:26578440

  14. Biomaterials for Nanoparticle Vaccine Delivery Systems

    PubMed Central

    Sahdev, Preety; Ochyl, Lukasz J.; Moon, James J.

    2014-01-01

    Subunit vaccination benefits from improved safety over attenuated or inactivated vaccines, but their limited capability to elicit long-lasting, concerted cellular and humoral immune responses is a major challenge. Recent studies have demonstrated that antigen delivery via nanoparticle formulations significantly improve immunogenicity of vaccines due to either intrinsic immunostimulatory properties of the materials or by co-entrapment of molecular adjuvants such as Toll-like receptor agonists. These studies have collectively shown that nanoparticles designed to mimic biophysical and biochemical cues of pathogens offer new exciting opportunities to enhance activation of innate immunity and elicit potent cellular and humoral immunity with minimal cytotoxicity. In this review, we present key research advances that were made within the last 5 years in the field of nanoparticle vaccine delivery systems. In particular, we focus on the impact of biomaterials composition, size, and surface charge of nanoparticles on modulation of particle biodistribution, delivery of antigens and immunostimulatory molecules, trafficking and targeting of antigen presenting cells, and overall immune responses in systemic and mucosal tissues. This review describes recent progresses in the design of nanoparticle vaccine delivery carriers, including liposomes, lipid-based particles, micelles and nanostructures composed of natural or synthetic polymers, and lipid-polymer hybrid nanoparticles. PMID:24848341

  15. In Situ Lipidization as a New Approach for the Design of a Self Microemulsifying Drug Delivery System (SMEDDS) of Doxorubicin Hydrochloride for Oral Administration.

    PubMed

    Derajram M Benival, M; Devarajan, Padma V

    2015-05-01

    The present paper reports in situ lipidization as a novel approach for the design of Dox-self microemulsifying drug delivery system (SMEDDS). Dox-aerosol OT (AOT) ion pair complex (lipidized Dox), exhibited high log P value of 1.74, indicating lipophilic nature. The lipidized Dox revealed good solubility but limited stability in various oils. Rapid complex formation of Dox with AOT dissolved in oils, and the high partitioning of lipidized Dox (-90%) into the oily phase presented in situ lipidization as a strategy to overcome the limited chemical stability of lipidized Dox. SMEDDS was prepared by mixing the lipidizing agent AOT, the surfactant α-Tocopheryl-Polyethyleneglycol-1 000-Succinate (TPGS) and Capmul as the oil. Dox was suspended in the SMEDDS to obtain Dox-SMEDDS. Dox-SMEDDS on aqueous dilution, resulted in a microemulsion with globule size 196 ± 16.56 nm, and revealed slow release of Dox. Oral bioavailability study in rats revealed a 420% enhancement from Dox-SMEDDS compared to Dox solution. Dox-SMEDDS and control group revealed comparable superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) levels in heart and kidneys suggesting safety of the Dox-SMEDDS. Efficacy study (tumor size reduction) in fibrosarcoma mouse model suggested Dox-SMEDDS as a promising oral delivery system for the treatment of cancer. In situ lipidization of Dox in SMEDDS presents a novel approach for the design of an orally bioavailable and promising formulation of Dox for oral administration. PMID:26390522

  16. Lipid-Based Drug Delivery Systems

    PubMed Central

    Shrestha, Hina; Bala, Rajni; Arora, Sandeep

    2014-01-01

    The principle objective of formulation of lipid-based drugs is to enhance their bioavailability. The use of lipids in drug delivery is no more a new trend now but is still the promising concept. Lipid-based drug delivery systems (LBDDS) are one of the emerging technologies designed to address challenges like the solubility and bioavailability of poorly water-soluble drugs. Lipid-based formulations can be tailored to meet a wide range of product requirements dictated by disease indication, route of administration, cost consideration, product stability, toxicity, and efficacy. These formulations are also a commercially viable strategy to formulate pharmaceuticals, for topical, oral, pulmonary, or parenteral delivery. In addition, lipid-based formulations have been shown to reduce the toxicity of various drugs by changing the biodistribution of the drug away from sensitive organs. However, the number of applications for lipid-based formulations has expanded as the nature and type of active drugs under investigation have become more varied. This paper mainly focuses on novel lipid-based formulations, namely, emulsions, vesicular systems, and lipid particulate systems and their subcategories as well as on their prominent applications in pharmaceutical drug delivery. PMID:26556202

  17. Controlled Release Strategies for Bone, Cartilage, and Osteochondral Engineering—Part I: Recapitulation of Native Tissue Healing and Variables for the Design of Delivery Systems

    PubMed Central

    Santo, Vítor E.; Mano, João F.; Reis, Rui L.

    2013-01-01

    The potential of growth factors to stimulate tissue healing through the enhancement of cell proliferation, migration, and differentiation is undeniable. However, critical parameters on the design of adequate carriers, such as uncontrolled spatiotemporal presence of bioactive factors, inadequate release profiles, and supraphysiological dosages of growth factors, have impaired the translation of these systems onto clinical practice. This review describes the healing cascades for bone, cartilage, and osteochondral interface, highlighting the role of specific growth factors for triggering the reactions leading to tissue regeneration. Critical criteria on the design of carriers for controlled release of bioactive factors are also reported, focusing on the need to provide a spatiotemporal control over the delivery and presentation of these molecules. PMID:23268651

  18. Design of Microbubbles for Gene/Drug Delivery.

    PubMed

    Bettinger, Thierry; Tranquart, François

    2016-01-01

    The role of ultrasound contrast agents (UCA) initially designed for diagnosis has evolved towards a therapeutic use. Ultrasound (US) for triggered drug delivery has many advantages. In particular, it enables a high spatial control of drug release, thus potentially allowing activation of drug delivery only in the targeted region, and not in surrounding healthy tissue. Moreover, UCA imaging can also be used firstly to precisely locate the target region to, and then used to monitor the drug delivery process by tracking the location of release occurrence. All these features make UCA and ultrasound attractive means to mediate drug delivery. The three main potential clinical indications for drug/gene US delivery are (i) the cardiovascular system, (ii) the central nervous system for small molecule delivery, and (iii) tumor therapy using cytotoxic drugs. Although promising results have been achieved in preclinical studies in various animal models, still very few examples of clinical use have been reported. In this chapter will be addressed the aspects pertaining to UCA formulation (chemical composition, mode of preparation, analytical methods…) and the requirement for a potential translation into the clinic following approval by regulatory authorities. PMID:26486339

  19. Design of Nanoparticle-Based Carriers for Targeted Drug Delivery

    PubMed Central

    Ren, Muqing; Duval, Kayla; Guo, Xing; Chen, Zi

    2016-01-01

    Nanoparticles have shown promise as both drug delivery vehicles and direct antitumor systems, but they must be properly designed in order to maximize efficacy. Computational modeling is often used both to design new nanoparticles and to better understand existing ones. Modeled processes include the release of drugs at the tumor site and the physical interaction between the nanoparticle and cancer cells. In this article, we provide an overview of three different targeted drug delivery methods (passive targeting, active targeting and physical targeting), compare methods of action, advantages, limitations, and the current stage of research. For the most commonly used nanoparticle carriers, fabrication methods are also reviewed. This is followed by a review of computational simulations and models on nanoparticle-based drug delivery. PMID:27398083

  20. Recent technologies in pulsatile drug delivery systems

    PubMed Central

    Jain, Deepika; Raturi, Richa; Jain, Vikas; Bansal, Praveen; Singh, Ranjit

    2011-01-01

    Pulsatile drug delivery systems (PDDS) have attracted attraction because of their multiple benefits over conventional dosage forms. They deliver the drug at the right time, at the right site of action and in the right amount, which provides more benefit than conventional dosages and increased patient compliance. These systems are designed according to the circadian rhythm of the body, and the drug is released rapidly and completely as a pulse after a lag time. These products follow the sigmoid release profile characterized by a time period. These systems are beneficial for drugs with chronopharmacological behavior, where nocturnal dosing is required, and for drugs that show the first-pass effect. This review covers methods and marketed technologies that have been developed to achieve pulsatile delivery. Marketed technologies, such as PulsincapTM, Diffucaps®, CODAS®, OROS® and PULSYSTM, follow the above mechanism to render a sigmoidal drug release profile. Diseases wherein PDDS are promising include asthma, peptic ulcers, cardiovascular ailments, arthritis and attention deficit syndrome in children and hypercholesterolemia. Pulsatile drug delivery systems have the potential to bring new developments in the therapy of many diseases. PMID:23507727

  1. An Approach to the Design of a Particulate System for Oral Protein Delivery .II. Preparation and Stability Study of rhGH-Loaded Microspheres in Simulated Gastrointestinal Fluids

    PubMed Central

    Nafissi Varcheh, Nastaran; Aboofazeli, Reza

    2011-01-01

    The delivery of therapeutic proteins has gained momentum with development of biotechnology. However, large molecular weight, hydrophilic nature and susceptibility to harsh environment of gastrointestinal tract (GIT) resulted in low absorption. The main objective of this work was the design of a particulate system for oral delivery of recombinant human growth hormone (rhGH) on the basis of particle uptake mechanism in GIT. Biodegradable protein-loaded microspheres were prepared using Resomers (RG207, RG756 and RG505) by double emulsion methods. Aqueous solution of protein and freshly prepared rhGH-zinc complex were used for loading process. Various analytical methods, including fluorescence spectroscopy, SDS-PAGE electrophoresis and reversed-phase chromatography, were set up for the quantification and qualification of rhGH before and after the formulation and fabrication procedures. At the optimum conditions, microspheres were mostly below 10 μm with relatively high protein loading (> 50%). Obtained data showed that the stability of protein did not change during the formulation and microencapsulation processes. Results also showed that the encapsulation process in the presence of zinc caused no detectable change in the protein chemical stability. In-vitro stability study of microspheres in different simulated GI media indicated that the entrapped protein was physically stable. Less than 20% of rhGH was released from the microspheres incubated in both simulated stomach and intestine fluids for 3 and 6 h, respectively. PMID:24250342

  2. Advanced rapid prototyping by laser beam sintering of metal prototypes: design and development of an optimized laser beam delivery system

    NASA Astrophysics Data System (ADS)

    Geiger, Manfred; Coremans, A.; Neubauer, Norbert; Niebling, F.

    1996-08-01

    Fast technological advances and steadily increasing severe worldwide competition force industry to respond all the time faster to new and chanced customer wishes. Some of the recently emerged processes, commonly referred to as 'rapid prototyping' (RP), have proved to be powerful tools for accelerating product and process development. Early approaches aimed at the automated production of plastic models. These techniques achieved industrial maturity extremely fast and are meanwhile established as standard utilities in the field of development/design processes. So far, their applicability to metal working industry was limited to design studies because the mechanical properties of the prototypes, e.g. modulus of elasticity and mechanical strength were not comparable to the final products they represented. Therefore, RP-processes aimed at the direct production of metallic prototypes gained more and more importance during recent years. A technique belonging to this group is manufacturing of prototypes by using a laser beam sintering machine capable of directly processing metal powders. This so called laser beam sintering process showed a great potential for direct manufacturing of functional tools and prototypes in early feasibility studies. Detailed examinations were performed at several research centers to determine the attainable quality of the parts concerning roughness, dimensional accuracy and mechanical strength. These examinations showed, that there still is a considerable demand for quality improvements of the previously mentioned parameters. The practical application and the potential for improvement of the geometrical accuracy of laser beam sintered parts by using a dual beam concept was proven. An innovative beam guiding and forming concept, similar to the previously mentioned patented beam guiding system, was developed and built with the goal to improve the process parameters governing mechanical properties as well as geometrical accuracy. Further reaching

  3. Hydrogen storage and delivery system development: Analysis

    SciTech Connect

    Handrock, J.L.

    1996-10-01

    Hydrogen storage and delivery is an important element in effective hydrogen utilization for energy applications and is an important part of the FY1994-1998 Hydrogen Program Implementation Plan. This project is part of the Field Work Proposal entitled Hydrogen Utilization in Internal Combustion Engines (ICE). The goal of the Hydrogen Storage and Delivery System Development Project is to expand the state-of-the-art of hydrogen storage and delivery system design and development. At the foundation of this activity is the development of both analytical and experimental evaluation platforms. These tools provide the basis for an integrated approach for coupling hydrogen storage and delivery technology to the operating characteristics of potential hydrogen energy use applications. Results of the analytical model development portion of this project will be discussed. Analytical models have been developed for internal combustion engine (ICE) hybrid and fuel cell driven vehicles. The dependence of hydride storage system weight and energy use efficiency on engine brake efficiency and exhaust temperature for ICE hybrid vehicle applications is examined. Results show that while storage system weight decreases with increasing engine brake efficiency energy use efficiency remains relatively unchanged. The development, capability, and use of a recently developed fuel cell vehicle storage system model will also be discussed. As an example of model use, power distribution and control for a simulated driving cycle is presented. Model calibration results of fuel cell fluid inlet and exit temperatures at various fuel cell idle speeds, assumed fuel cell heat capacities, and ambient temperatures are presented. The model predicts general increases in temperature with fuel cell power and differences between inlet and exit temperatures, but under predicts absolute temperature values, especially at higher power levels.

  4. Nanogel Carrier Design for Targeted Drug Delivery

    PubMed Central

    Eckmann, D. M.; Composto, R. J.; Tsourkas, A.; Muzykantov, V. R.

    2014-01-01

    Polymer-based nanogel formulations offer features attractive for drug delivery, including ease of synthesis, controllable swelling and viscoelasticity as well as drug loading and release characteristics, passive and active targeting, and the ability to formulate nanogel carriers that can respond to biological stimuli. These unique features and low toxicity make the nanogels a favorable option for vascular drug targeting. In this review, we address key chemical and biological aspects of nanogel drug carrier design. In particular, we highlight published studies of nanogel design, descriptions of nanogel functional characteristics and their behavior in biological models. These studies form a compendium of information that supports the scientific and clinical rationale for development of this carrier for targeted therapeutic interventions. PMID:25485112

  5. Design and development of a multifunctional nano carrier system for imaging, drug delivery, and cell targeting in cancer research

    NASA Astrophysics Data System (ADS)

    Cho, Hoon-Sung

    There has been an increasing need in the last decade for early diagnosis and treatment of cancer prior to the tumor mass becoming evident as anatomical anomaly. A major challenge in cancer diagnosis is to distinguish cancer cells from the surrounding, normal tissue. For early cancer diagnosis and treatment, a nano carrier system was designed and developed with key components uniquely structured according to biomedical and clinical requirements: targeting, drug storage capabilities, fluorescent emissions near the infrared range for in vivo imaging, and magnetic hyperthermia. For in vivo imaging, quantum dots with emissions near infrared range (˜800 nm) were conjugated onto the surface of carbon nanotubes and nanospheres consisting of a spherical polystyrene matrix (˜100 nm) and high fraction of superparamagnetic Fe3O4 nanoparticles (˜10 nm) embedded. The QDs on these nano carriers exhibited intense visible emissions using fluorescent spectroscopy and successfully facilitated in vivo soft tissue imaging in mice. For drug storage, the chemotherapeutic agent, paclitaxel (PTX) was loaded onto the surfaces of these nano-carriers by using a layer of biodegradable poly(lactic-co-glycolic acid) (PLGA). A cell-based cytotoxicity assay was employed to verify successful loading of pharmacologically active drug, PTX. Cell viability of human, metastatic PC3mm2 prostate cancer cells was assessed in the presence and absence of various nano-carrier populations using the MTT assay. For hyperthermia, Fe3O 4 nanoparticles were conjugated onto the surfaces of carbon nanotubes (CNT) and embedded into the nanospheres. Magnetization measurements showed nearly reversible hysteresis curves from the Fe3O4-conjugated CNTs and the magnetic nanospheres (MNS). Application of an alternating electromagnetic field effectively induced heating the solution of the Fe3O 4-conjugated CNTs and the magnetic nanospheres (MNS) into temperature ranges (up to 55ºC) suitable for therapeutic hyperthermia

  6. Design, Synthesis of Novel Lipids as Chemical Permeation Enhancers and Development of Nanoparticle System for Transdermal Drug Delivery

    PubMed Central

    Shah, Punit P.; Etukala, Jagan Reddy; Vemuri, Adithi; Singh, Mandip

    2013-01-01

    In the present study, we designed and developed novel lipids that include (Z)-1-(Octadec-9-en-1-yl)-pyrrolidine (Cy5T), 1, 1-Di-((Z)-octadec-9-en-1-yl)pyrrolidin-1-ium iodide (Cy5), (Z)-1-(Octadec-9-en-1-yl)-piperidine (Cy6T), and 1, 1-Di-((Z)-octadec-9-en-1-yl) piperidin-1-ium iodide (Cy6) to enhance the transdermal permeation of some selected drugs. Firstly, we evaluated the transdermal permeation efficacies of these lipids as chemical permeation enhancers in vehicle formulations for melatonin, ß-estradiol, caffeine, α-MSH, and spantide using franz diffusion cells. Among them Cy5 lipid was determined to be the most efficient by increasing the transdermal permeation of melatonin, ß-estradiol, caffeine, α-MSH, and spantide by 1.5 to 3.26-fold more at the epidermal layer and 1.3 to 2.5-fold more at the dermal layer, in comparison to either NMP or OA. Hence we developed a nanoparticle system (cy5 lipid ethanol drug nanoparticles) to evaluate any further improvement in the drug penetration. Cy5 lipid formed uniformly sized nanoparticles ranging from 150–200 nm depending on the type of drug. Further, Cy5 based nanoparticle system significantly (p<0.05) increased the permeation of all the drugs in comparison to the lipid solution and standard permeation enhancers. There were about 1.54 to 22-fold more of drug retained in the dermis for the Cy5 based nanoparticles compared to OA/NMP standard enhancers and 3.87 to 66.67-fold more than lipid solution. In addition, epifluorescent microscopic analysis in rhodamine-PE permeation studies confirmed the superior permeation enhancement of LEDs (detection of fluorescence up to skin depth of 340 μm) more than lipid solution, which revealed fluorescence up to skin depth of only 260 μm. In summary the present findings demonstrate that i) cationic lipid with 5 membered amine heterocyclic ring has higher permeating efficacy than the 6 membered amine hertocyclic ring. ii) The nanoparticle system prepared with Cy5 showed

  7. Rational design of liposomal drug delivery systems, a review: Combined experimental and computational studies of lipid membranes, liposomes and their PEGylation.

    PubMed

    Bunker, Alex; Magarkar, Aniket; Viitala, Tapani

    2016-10-01

    Combined experimental and computational studies of lipid membranes and liposomes, with the aim to attain mechanistic understanding, result in a synergy that makes possible the rational design of liposomal drug delivery system (LDS) based therapies. The LDS is the leading form of nanoscale drug delivery platform, an avenue in drug research, known as "nanomedicine", that holds the promise to transcend the current paradigm of drug development that has led to diminishing returns. Unfortunately this field of research has, so far, been far more successful in generating publications than new drug therapies. This partly results from the trial and error based methodologies used. We discuss experimental techniques capable of obtaining mechanistic insight into LDS structure and behavior. Insight obtained purely experimentally is, however, limited; computational modeling using molecular dynamics simulation can provide insight not otherwise available. We review computational research, that makes use of the multiscale modeling paradigm, simulating the phospholipid membrane with all atom resolution and the entire liposome with coarse grained models. We discuss in greater detail the computational modeling of liposome PEGylation. Overall, we wish to convey the power that lies in the combined use of experimental and computational methodologies; we hope to provide a roadmap for the rational design of LDS based therapies. Computational modeling is able to provide mechanistic insight that explains the context of experimental results and can also take the lead and inspire new directions for experimental research into LDS development. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg. PMID:26915693

  8. Integrated delivery systems. Evolving oligopolies.

    PubMed

    Malone, T A

    1998-01-01

    The proliferation of Integrated Delivery Systems (IDSs) in regional health care markets has resulted in the movement of these markets from a monopolistic competitive model of behavior to an oligopoly. An oligopoly is synonymous with competition among the few, as a small number of firms supply a dominant share of an industry's total output. The basic characteristics of a market with competition among the few are: (1) A mutual interdependence among the actions and behaviors of competing firms; (2) competition tends to rely on the differentiation of products; (3) significant barriers to entering the market exist; (4) the demand curve for services may be kinked; and (5) firms can benefit from economies of scale. An understanding of these characteristics is essential to the survival of IDSs as regional managed care markets mature. PMID:10180497

  9. Microfabricated injectable drug delivery system

    DOEpatents

    Krulevitch, Peter A.; Wang, Amy W.

    2002-01-01

    A microfabricated, fully integrated drug delivery system capable of secreting controlled dosages of multiple drugs over long periods of time (up to a year). The device includes a long and narrow shaped implant with a sharp leading edge for implantation under the skin of a human in a manner analogous to a sliver. The implant includes: 1) one or more micromachined, integrated, zero power, high and constant pressure generating osmotic engine; 2) low power addressable one-shot shape memory polymer (SMP) valves for switching on the osmotic engine, and for opening drug outlet ports; 3) microfabricated polymer pistons for isolating the pressure source from drug-filled microchannels; 4) multiple drug/multiple dosage capacity, and 5) anisotropically-etched, atomically-sharp silicon leading edge for penetrating the skin during implantation. The device includes an externally mounted controller for controlling on-board electronics which activates the SMP microvalves, etc. of the implant.

  10. Bio-mimetic drug delivery systems designed to help the senior population reconstruct melatonin plasma profiles similar to those of the healthy younger population

    PubMed Central

    Li, Ying; Wang, Liuyi; Wu, Li; Zhang, Xueju; Li, Xue; Guo, Zhen; Li, Haiyan; York, Peter; Gui, Shuangying; Zhang, Jiwen

    2014-01-01

    The secretion of melatonin (MT) is obviously different in the younger and the senior sectors of the population, and the maximum plasma concentration of seniors is only half of that in the younger population group. If exogenous MT can be supplied to senior citizens based on the secretion rate and amount of endogenous MT in the younger population by a bio-mimetic drug delivery system (DDS), an improved therapeutic effect and reduced side effects can be expected. Based upon this hypothesis, the pharmacokinetic parameters of MT, namely, the absorption rate constant (ka), the elimination rate constant (ke), and the ratio of absorption rate (F) to the apparent volume of distribution (V) were obtained by a residual method depending on the plasma concentration curve of immediate release preparations in the healthy younger population. The dose-division method was applied to calculate the cumulative release profiles of MT achieved by oral administration of a controlled release drug delivery system (DDS) to generate plasma MT profiles similar to the physiological level-time profiles. The in vivo release of MT deduced from the healthy younger population physiological MT profiles as the pharmacokinetic output of the bio-mimetic DDS showed a two-phase profile with two different zero order release rates, namely, 4.919 μg/h during 0–4 h (r=0.9992), and 11.097 μg/h during 4–12 h (r=0.9886), respectively. Since the osmotic pump type of DDS generally exhibits a good correlation between in vivo and in vitro release behaviors, an osmotic pump controlled delivery system was designed in combination with dry coating technology targeting on the cumulative release characteristics to mimic the physiological MT profiles in the healthy younger population. The high similarity between the experimental drug release profiles and the theoretical profiles (similarity factor f2>50) and the high correlation between the predicted plasma concentration profiles and the theoretical plasma

  11. A designed 5-fluorouracil-based bridged silsesquioxane as an autonomous acid-triggered drug-delivery system.

    PubMed

    Giret, Simon; Théron, Christophe; Gallud, Audrey; Maynadier, Marie; Gary-Bobo, Magali; Garcia, Marcel; Wong Chi Man, Michel; Carcel, Carole

    2013-09-16

    Two new prodrugs, bearing two and three 5-fluorouracil (5-FU) units, respectively, have been synthesized and were shown to efficiently treat human breast cancer cells. In addition to 5-FU, they were intended to form complexes through H-bonds to an organo-bridged silane prior to hydrolysis-condensation through sol-gel processes to construct acid-responsive bridged silsesquioxanes (BS). Whereas 5-FU itself and the prodrug bearing two 5-FU units completely leached out from the corresponding materials, the prodrug bearing three 5-FU units was successfully maintained in the resulting BS. Solid-state NMR ((29) Si and (13) C) spectroscopy show that the organic fragments of the organo-bridged silane are retained in the hybrid through covalent bonding and the (1) H NMR spectroscopic analysis provides evidence for the hydrogen-bonding interactions between the prodrug bearing three 5-FU units and the triazine-based hybrid matrix. The complex in the BS is not affected under neutral medium and operates under acidic conditions even under pH as high as 5 to deliver the drug as demonstrated by HPLC analysis and confirmed by FTIR and (13) C NMR spectroscopic studies. Such functional BS are promising materials as carriers to avoid the side effects of the anticancer drug 5-FU thanks to a controlled and targeted drug delivery. PMID:23929826

  12. The Controlled Drug Delivery Systems: Past Forward and Future Back

    PubMed Central

    Park, Kinam

    2014-01-01

    The controlled drug delivery technology has progressed over the last six decades. It began in 1952 with the introduction of the first sustained release formulation. The 1st generation (1950-1980) of drug delivery was focused on developing oral and transdermal sustained release systems and establishing the controlled drug release mechanisms. Attention of the 2nd generation (1980-2010) was dedicated to development of zero-order release systems, self-regulated drug delivery systems, long-term depot formulations, and nanotechnology-based delivery systems. The latter part of the 2nd generation was consumed mostly for studying nanoparticle formulations. The Journal of Controlled Release (JCR) has played a pivotal role during the 2nd generation of drug delivery technologies, and it will continue playing a leading role for the next generation. Taking the right path towards the productive 3rd generation of drug delivery technologies requires honest open dialogues without any preconceived ideas of the past. The drug delivery field needs to take a bold approach of designing the future drug delivery formulations first, based on today’s necessities, and produce necessary innovations. The JCR will provide the forum for sharing the new ideas that will shape the 3rd generation of drug delivery technologies. PMID:24794901

  13. Fiber coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan

    2008-08-12

    A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

  14. Physically facilitating drug-delivery systems

    PubMed Central

    Rodriguez-Devora, Jorge I; Ambure, Sunny; Shi, Zhi-Dong; Yuan, Yuyu; Sun, Wei; Xu, Tao

    2012-01-01

    Facilitated/modulated drug-delivery systems have emerged as a possible solution for delivery of drugs of interest to pre-allocated sites at predetermined doses for predefined periods of time. Over the past decade, the use of different physical methods and mechanisms to mediate drug release and delivery has grown significantly. This emerging area of research has important implications for development of new therapeutic drugs for efficient treatments. This review aims to introduce and describe different modalities of physically facilitating drug-delivery systems that are currently in use for cancer and other diseases therapy. In particular, delivery methods based on ultrasound, electrical, magnetic and photo modulations are highlighted. Current uses and areas of improvement for these different physically facilitating drug-delivery systems are discussed. Furthermore, the main advantages and drawbacks of these technologies reviewed are compared. The review ends with a speculative viewpoint of how research is expected to evolve in the upcoming years. PMID:22485192

  15. Cavity Design, Fabrication and Commission Performance of a 750MHz, 4-rod Separator for CEBAF 4-Hall Beam Delivery System

    SciTech Connect

    Wang, Haipeng; Cheng, Guangfeng; Turlington, Larry T.; Wissmann, Mark J.

    2015-09-01

    A short version of the original CEBAF normal conducting 4-rod separator cavity has been developed into a 750MHz one * since the concept of simultaneous 4-hall operation for CEBAF is introduced **. This work has been advanced further based on the EM design optimization, bench measurement and by conducting RF-thermal coupled simulation using CST and ANSYS to confirm the cavity tuning and thermal performance. The cavity fabrication used matured technology like copper plating and machining. The cavity flanges, couplers, tuners and cooling channels adopted consistent/compatible hardware with the existing 500MHz cavities. The electromagnetic and thermal design simulations have greatly reduced the prototyping and bench tuning time of the first prototype. Four production cavities have reached a typical 1.94MV kick voltage or 3.0kW wall loss on each cavity after a minor multipactoring or no processing, 7.5% overhead power than the design specification.

  16. Development and optimization of a self-microemulsifying drug delivery system for ator vastatin calcium by using d-optimal mixture design

    PubMed Central

    Yeom, Dong Woo; Song, Ye Seul; Kim, Sung Rae; Lee, Sang Gon; Kang, Min Hyung; Lee, Sangkil; Choi, Young Wook

    2015-01-01

    In this study, we developed and optimized a self-microemulsifying drug delivery system (SMEDDS) formulation for improving the dissolution and oral absorption of atorvastatin calcium (ATV), a poorly water-soluble drug. Solubility and emulsification tests were performed to select a suitable combination of oil, surfactant, and cosurfactant. A d-optimal mixture design was used to optimize the concentration of components used in the SMEDDS formulation for achieving excellent physicochemical characteristics, such as small droplet size and high dissolution. The optimized ATV-loaded SMEDDS formulation containing 7.16% Capmul MCM (oil), 48.25% Tween 20 (surfactant), and 44.59% Tetraglycol (cosurfactant) significantly enhanced the dissolution rate of ATV in different types of medium, including simulated intestinal fluid, simulated gastric fluid, and distilled water, compared with ATV suspension. Good agreement was observed between predicted and experimental values for mean droplet size and percentage of the drug released in 15 minutes. Further, pharmacokinetic studies in rats showed that the optimized SMEDDS formulation considerably enhanced the oral absorption of ATV, with 3.4-fold and 4.3-fold increases in the area under the concentration-time curve and time taken to reach peak plasma concentration, respectively, when compared with the ATV suspension. Thus, we successfully developed an optimized ATV-loaded SMEDDS formulation by using the d-optimal mixture design, that could potentially be used for improving the oral absorption of poorly water-soluble drugs. PMID:26089663

  17. Design Project on Controlled-Release Drug Delivery Devices: Implementation, Management, and Learning Experiences

    ERIC Educational Resources Information Center

    Xu, Qingxing; Liang, Youyun; Tong, Yen Wah; Wang, Chi-Hwa

    2010-01-01

    A design project that focuses on the subject of controlled-release drug delivery devices is presented for use in an undergraduate course on mass transfer. The purpose of the project is to introduce students to the various technologies used in the fabrication of drug delivery systems and provide a practical design exercise for understanding the…

  18. Development of the Choctaw Health Delivery System.

    ERIC Educational Resources Information Center

    Nguyen, Binh N.

    The Choctaw Tribe is the first and only tribe to develop a health delivery system to take over an existing Indian Health Service inpatient facility. The takeover was accomplished in January 1984 under the Indian Self-Determination Act through a contract with the Indian Health Service. The Choctaw Health Delivery System includes a 35-bed general…

  19. Understanding the photothermal heating effect in non-lamellar liquid crystalline systems, and the design of new mixed lipid systems for photothermal on-demand drug delivery.

    PubMed

    Fong, Wye-Khay; Hanley, Tracey L; Thierry, Benjamin; Tilley, Adam; Kirby, Nigel; Waddington, Lynne J; Boyd, Ben J

    2014-12-01

    Lipid-based liquid crystalline systems are showing potential as stimuli-responsive nanomaterials, and NIR-responsive gold nanoparticles have been demonstrated to provide control of transitions in non-lamellar phases. In this study, we focus on a deeper understanding of the photothermal response of both lamellar and non-lamellar phases, and new systems formed by alternative lipid systems not previously reported, by linking the photothermal heating to the bulk thermal properties of the materials. Dynamic photothermal studies were performed using NIR laser irradiation and monitoring the structural response using time resolved small angle X-ray scattering for the bulk phases and hexosomes. In addition, cryoFESEM and cryoTEM were used to visualise and assess the effect of GNR incorporation into hexagonal phase nanostructures. The ability of the systems to respond to photothermal heating was correlated with the thermal phase behaviour and heat capacities of the different structures. Access to alternative phase transitions in these systems and understanding the likely photothermal response will facilitate different modes of application of these hybrid nanomaterials for on-demand drug delivery applications. PMID:25325902

  20. High and low energy gamma beam dump designs for the gamma beam delivery system at ELI-NP

    NASA Astrophysics Data System (ADS)

    Yasin, Zafar; Matei, Catalin; Ur, Calin A.; Mitu, Iani-Octavian; Udup, Emil; Petcu, Cristian

    2016-03-01

    The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) is under construction in Magurele, Bucharest, Romania. The facility will use two 10 PW lasers and a high intensity, narrow bandwidth gamma beam for stand-alone and combined laser-gamma experiments. The accurate estimation of particle doses and their restriction within the limits for both personel and general public is very important in the design phase of any nuclear facility. In the present work, Monte Carlo simulations are performed using FLUKA and MCNPX to design 19.4 and 4 MeV gamma beam dumps along with shielding of experimental areas. Dose rate contour plots from both FLUKA and MCNPX along with numerical values of doses in experimental area E8 of the facility are performed. The calculated doses are within the permissible limits. Furthermore, a reasonable agreement between both codes enhances our confidence in using one or both of them for future calculations in beam dump designs, radiation shielding, radioactive inventory, and other calculations releated to radiation protection. Residual dose rates and residual activity calculations are also performed for high-energy beam dump and their effect is negligible in comparison to contributions from prompt radiation.

  1. Gastroretentive delivery systems: hollow beads.

    PubMed

    Talukder, R; Fassihi, R

    2004-04-01

    The objective of this study was to develop a floatable multiparticulate system with potential for intragastric sustained drug delivery. Cross-linked beads were made by using calcium and low methoxylated pectin (LMP), which is an anionic polysaccharide, and calcium, LMP, and sodium alginate. Beads were dried separately in an air convection type oven at 40 degrees C for 6 hours and in a freeze dryer to evaluate the changes in bead characteristics due to process variability. Riboflavin (B-2), tetracycline (TCN), and Methotrexate (MTX) were used as model drugs for encapsulation. Ionic and nonionic excipients were added to study their effects on the release profiles of the beads. The presence of noncross linking agents in low amounts (less than 2%) did not significantly interfere with release kinetics. For an amphoteric drug like TCN, which has pH dependent solubility, three different pHs (1.5, 5.0, and 8.0) of cross-linking media were used to evaluate the effects of pH on the drug entrapment capacity of the beads. As anticipated, highest entrapment was possible when cross-linking media pH coincided with least drug solubility. Evaluation of the drying process demonstrated that the freeze-dried beads remained buoyant over 12 hours in United States Pharmacopeia (USP) hydrochloride buffer at pH 1.5, whereas the air-dried beads remained submerged throughout the release study. Confocal laser microscopy revealed the presence of air-filled hollow spaces inside the freeze dried beads, which was responsible for the flotation property of the beads. However, the release kinetics from freeze dried beads was independent of hydrodynamic conditions. Calcium-pectinate-alginate beads released their contents at much faster rates than did calcium-pectinate beads (100% in 10 hours vs. 50% in 10 hours). It appears that the nature of cross-linking, drying method, drug solubility, and production approach are all important and provide the opportunity and potential for development of a

  2. Preparation of a beta-Cyclodextrin Supramolecular Nanoparticle as a Drug Delivery System The design, preparation and properties

    NASA Astrophysics Data System (ADS)

    Xin, Junjun

    Steam generator unit in nuclear power plant comprise thousands of heat exchange tubes whereby heat from primary coolant is transferred to water circulating on the secondary side. A variety of tube degradation due to mechanical vibration and chemical interactions compromises the integrity of steam generator tubes. The rupture of these tubes may result in leakage of radioactive water to the environment. Periodic inspections aimed at timely detection and characterization of the degradation is a key element for ensuring tube integrity and safe operation of nuclear power plant. Eddy current testing has proved to be an effective technique to detect defects occurring in the tube wall. In the past two decades, three types eddy current probes developed for steam generator tube inspection include bobbin coil probe, rotating probe and array probe. Each of these probes has their own limitations. The bobbin coil probe is insensitive to circumferential cracks, and rotating probe is slow and involves complex mechanical rotation whereas the array probe has poor resolution and high cost of instrumentation. This dissertation presents the design and validation of a new rotating field eddy current probe. The probe is composed of three phase rectangular windings and pickup sensor, that can be chosen to be a simple bobbin coil or a GMR array sensor placed at the probe center. The probe avoids mechanical rotation and has fast scan speed. The rotating field probe is sensitive to all orientation defects. The axial component of magnetic field along the tubing due to a defect is measured by the pickup sensor. The probe design and performance are evaluated using an experimental validated finite element model. A reduced magnetic vector potential formulation is used for simulating the different commercial probe as well as the proposed new probe design. A probe prototype is built to validate the simulation results with respect to different defects. A parametric study is conducted using the model

  3. Drug delivery systems: An updated review

    PubMed Central

    Tiwari, Gaurav; Tiwari, Ruchi; Sriwastawa, Birendra; Bhati, L; Pandey, S; Pandey, P; Bannerjee, Saurabh K

    2012-01-01

    Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. For the treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining increasing importance. These routes provide promising alternatives to parenteral drug delivery particularly for peptide and protein therapeutics. For this purpose, several drug delivery systems have been formulated and are being investigated for nasal and pulmonary delivery. These include liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins, among others. Nanoparticles composed of biodegradable polymers show assurance in fulfilling the stringent requirements placed on these delivery systems, such as ability to be transferred into an aerosol, stability against forces generated during aerosolization, biocompatibility, targeting of specific sites or cell populations in the lung, release of the drug in a predetermined manner, and degradation within an acceptable period of time. PMID:23071954

  4. Design and development of novel lipid based gastroretentive delivery system: response surface analysis, in-vivo imaging and pharmacokinetic study.

    PubMed

    Ahmed Abdelbary, Aly; Elsayed, Ibrahim; Hassen Elshafeey, Ahmed

    2015-01-01

    Famotidine HCl has low bioavailability (40-45%) due to its narrow absorption window and low solubility in intestinal pH. Lipids were utilized in the formulation of novel gastroretentive dosage forms to increase the availability of famotidine HCl at its absorption site. Novel non-swellable gastroretentive lipid disks (D) and swellable compression coated tablets with a lipid core (T) were prepared. Formulae were characterized by friability testing, in-vitro buoyancy, in-vitro drug release and scanning electron microscopy (SEM). Factorial designs of 2(2 )× 3(1) and 3(2) were planned for the optimization of disks and tablets, respectively, using Design-Expert® software. X-ray imaging was used for the in-vivo visualization of the selected formula in human gastrointestinal tract (GIT). Moreover, a bioavailability study was performed in healthy human volunteers using the optimized disk formula (D10). Results showed that formulae D10 (containing stearyl alcohol and polyethylene glycol in a ratio of 9:1 w/w) and T7 (containing polyethylene oxide only) had highest desirability values (0.684 and 0.842, respectively). Lipids achieved instantaneous floating and sustained the release of famotidine HCl over a prolonged period of time with significant bioavailability enhancement. PMID:24350634

  5. The design, fabrication and delivery of a spacelab neutral buoyancy Instrument Pointing System (IPS) mockup. [underwater training simulator

    NASA Technical Reports Server (NTRS)

    Vanvalkenburgh, C. N.

    1984-01-01

    Underwater simulations of EVA contingency operations such as manual jettison, payload disconnect, and payload clamp actuation were used to define crew aid needs and mockup pecularities and characteristics to verify the validity of simulation using the trainer. A set of mockup instrument pointing system tests was conducted and minor modifications and refinements were made. Flight configuration struts were tested and verified to be operable by the flight crew. Tasks involved in developing the following end items are described: IPS gimbal system, payload, and payload clamp assembly; the igloos (volumetric); spacelab pallets, experiments, and hardware; experiment, and hardware; experiment 7; and EVA hand tools, support hardware (handrails and foot restraints). The test plan preparation and test support are also covered.

  6. Validation of an automated punctate mechanical stimuli delivery system designed for fMRI studies in rodents.

    PubMed

    Governo, Ricardo Jose Moylan; Prior, Malcolm John William; Morris, Peter Gordon; Marsden, Charles Alexander; Chapman, Victoria

    2007-06-15

    Functional magnetic resonance imaging (fMRI) is increasingly being used for animal studies studying the transmission of nociceptive information. Application of noxious mechanical stimuli is widely used for animal and human assessment of pain processing. Any accessory hardware used in animal imaging studies must, however, be sufficiently small to fit in the magnet bore diameter and be non-magnetic. We have developed a system that can apply mechanical stimuli simultaneously with fMRI. This system consists of a standardized instrument to deliver mechanical stimuli (VonFrey monofilament) and a gas-pressured mechanical transducer. These components were integrated with a computer console that controlled the period of stimuli to match acquisition scans. Preliminary experiments demonstrated that the force-stimulus transducer did not influence MRI signal to noise ratio. Mechanical stimulation of the hindpaw significantly increased blood oxygen level dependent (BOLD) signal intensity in several midbrain regions involved in the processing of nociceptive information in the rat (p<0.001, uncorrected for multiple comparisons). This system can be applied to both animal and human imaging studies and has a wide range of applications for studies of nociceptive processing. PMID:17368787

  7. Fibrin Glue as a Drug Delivery System

    PubMed Central

    Spicer, Patrick P.; Mikos, Antonios G.

    2010-01-01

    Fibrin glue has been used surgically for decades for hemostasis as well as a sealant. It has also been researched as both a gel for cell delivery and a vehicle for drug delivery. The drug delivery applications for fibrin glue span tissue engineering to chemotherapy and involve several mechanisms for drug matrix interactions and control of release kinetics. Additionally, drugs or factors can be loaded in the gel via impregnation and tethering to the gel through covalent linkages or affinity based systems. This review highlights recent research of fibrin glue as a drug delivery vehicle. PMID:20637815

  8. Design and Application of Multifunctional DNA Nanocarriers for Therapeutic Delivery

    PubMed Central

    Charoenphol, Phapanin; Bermudez, Harry

    2013-01-01

    The unique programmability of nucleic acids offers versatility and flexibility in the creation of self-assembled DNA nanostructures. To date, many three-dimensional DNA architectures have been precisely formed of varying sizes and shapes. Their biocompatibility, biodegradability, and high intrinsic stability in physiological environments emphasize their emerging use as carriers for drug and gene delivery. Furthermore, DNA nanocarriers have been shown to enter cells efficiently and without the aid of transfection reagents. A key strength of DNA nanocarriers over other delivery systems is their modularity and their ability to control the spatial distribution of cargoes and ligands. Optimizing DNA nanocarrier properties to dictate their localization, uptake, and intracellular trafficking is also possible. In this review, we present design considerations for DNA nanocarriers and examples of their use in the context of therapeutic delivery applications. The assembly of DNA nanocarriers and approaches for loading and releasing cargo are described. The stability and safety of DNA nanocarriers is also discussed, with particular attention to the in vivo physiological environment. Mechanisms of cellular uptake and intracellular trafficking are examined, and we conclude with strategies to enhance the delivery efficiency of DNA nanocarriers. PMID:23896566

  9. Design and evaluation of a brinzolamide drug-resin in situ thermosensitive gelling system for sustained ophthalmic drug delivery.

    PubMed

    Li, Jing; Liu, Hua; Liu, Li-li; Cai, Chao-nan; Xin, Hong-xia; Liu, Wei

    2014-01-01

    In this study a brinzolamide drug-resin ophthalmic thermosensitive in situ gelling system was developed and evaluated. Brinzolamide was combined with ion exchange resins to prolong the retention time of drugs in the eye and to reduce ocular and systemic side effects. Poloxamer F127 was used as gelling vehicle in combination with carbopol 934P, which acted as a viscosity-enhancing agent. They were prepared using the cold method. The optimized formulation exhibited a sol-gel transition at 33.2±1.1°C with pseudoplastic flow behavior. This formulation was stable and nonirritant to rabbit eyes. In vitro release studies demonstrated diffusion-controlled release of brinzolamide from the combined solutions over a period of 8 h. In vivo evaluation (the elimination of brinzolamide through tears and absorption of brinzolamide in aqueous humor) indicated that the solution combination was better able to retain the drug than commercial preparations. Thus this formulation is safe for ophthalmic use and significantly increases brinzolamide bioavailability in aqueous humor. PMID:25099146

  10. Synthesis and Charactersiation of Chitosan conjugate; Design and Evaluation of Membrane Moderated Type Transdermal Drug Delivery System

    PubMed Central

    Satheeshababu, B. K.; Shruthinag, R.

    2015-01-01

    The purpose of the present research investigation was to synthesis, characterisation of chitosan conjugates and its effect on drug permeation from transdermal rate controlling membrane. Chitosan conjugate was synthesised by conjugation with thioglycolic acid. The prepared chitosan conjugate was characterised by determining the charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. The rate controlling membranes were prepared by various proportions of chitosan and chitosan conjugate, to moderate drug permeation through rate controlling membrane. The membrane moderated transdermal system consists of reservoir to hold the drug gel was prepared by 20% w/v ethylcellulose with a cavity in its center. An impermeable backing layer was prepared by 2% w/v ethylcellulose. Gel consists of carvedilol was prepared by sodium alginate and sodium carboxymethylcellulose in ethanol:water solvent system The rate controlling membranes prepared were evaluated by various parameters like thickness, folding endurance, swelling index, moisture content, moisture uptake, water vapor transmission rate, tensile strength test, measurement of gel strength, in vitro permeation study, ex vivo permeation study, compatibility study using differential scanning calorimetry and stability studies. All physical parameters evident that prepared membranes have good folding endurance and sufficient tensile strength. As the proportion of chitosan conjugate increases in membrane swelling index, moisture content, moisture uptake and permeability coefficient increases. The gel strength of chitosan conjugate was considerable less compared with chitosan. PMID:26664056

  11. Synthesis and Charactersiation of Chitosan conjugate; Design and Evaluation of Membrane Moderated Type Transdermal Drug Delivery System.

    PubMed

    Satheeshababu, B K; Shruthinag, R

    2015-01-01

    The purpose of the present research investigation was to synthesis, characterisation of chitosan conjugates and its effect on drug permeation from transdermal rate controlling membrane. Chitosan conjugate was synthesised by conjugation with thioglycolic acid. The prepared chitosan conjugate was characterised by determining the charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. The rate controlling membranes were prepared by various proportions of chitosan and chitosan conjugate, to moderate drug permeation through rate controlling membrane. The membrane moderated transdermal system consists of reservoir to hold the drug gel was prepared by 20% w/v ethylcellulose with a cavity in its center. An impermeable backing layer was prepared by 2% w/v ethylcellulose. Gel consists of carvedilol was prepared by sodium alginate and sodium carboxymethylcellulose in ethanol:water solvent system The rate controlling membranes prepared were evaluated by various parameters like thickness, folding endurance, swelling index, moisture content, moisture uptake, water vapor transmission rate, tensile strength test, measurement of gel strength, in vitro permeation study, ex vivo permeation study, compatibility study using differential scanning calorimetry and stability studies. All physical parameters evident that prepared membranes have good folding endurance and sufficient tensile strength. As the proportion of chitosan conjugate increases in membrane swelling index, moisture content, moisture uptake and permeability coefficient increases. The gel strength of chitosan conjugate was considerable less compared with chitosan. PMID:26664056

  12. Design attributes of long-circulating polymeric drug delivery vehicles.

    PubMed

    Beck-Broichsitter, Moritz; Nicolas, Julien; Couvreur, Patrick

    2015-11-01

    Following systemic administration polymeric drug delivery vehicles allow for a controlled and targeted release of the encapsulated medication at the desired site of action. For an elevated and organ specific accumulation of their cargo, nanocarriers need to avoid opsonization, activation of the complement system and uptake by macrophages of the mononuclear phagocyte system. In this respect, camouflaged vehicles revealed a delayed elimination from systemic circulation and an improved target organ deposition. For instance, a steric shielding of the carrier surface by poly(ethylene glycol) substantially decreased interactions with the biological environment. However, recent studies disclosed possible deficits of this approach, where most notably, poly(ethylene glycol)-modified drug delivery vehicles caused significant immune responses. At present, identification of novel potential carrier coating strategies facilitating negligible immune reactions is an emerging field of interest in drug delivery research. Moreover, physical carrier properties including geometry and elasticity seem to be very promising design attributes to surpass numerous biological barriers, in order to improve the efficacy of the delivered medication. PMID:25857838

  13. Fiber laser coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-03-04

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  14. Delivery system for laser medical instrument

    NASA Astrophysics Data System (ADS)

    Jelinkova, Helena; Nemec, Michal; Sulc, Jan; Cerny, Pavel; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2003-10-01

    Investigation of the special constructed hollow glass waveguides was realized. Maximum mean power transmitted via this delivery system was 5.8 W (for alexandrite radiation) or 5.1 W (for mid infrared Er.YAG light). Maximum output intensity 173 GW/cm2 was reached for delivery of 55 psec long Nd:YAG pulses.

  15. Micro-porous surfaces in controlled drug delivery systems: design and evaluation of diltiazem hydrochloride controlled porosity osmotic pump using non-ionic surfactants as pore-former.

    PubMed

    Adibkia, Khosro; Ghanbarzadeh, Saeed; Shokri, Mohammad Hosein; Arami, Zahra; Arash, Zeinab; Shokri, Javad

    2014-06-01

    The major problem associated with conventional drug delivery systems is unpredictable plasma concentrations. The aim of this study was to design a controlled porosity osmotic pump (CPOP) of diltiazem hydrochloride to deliver the drug in a controlled manner. CPOP tablets were prepared by incorporation of drug in the core and subsequent coating with cellulose acetate as semi-permeable membrane. Non-ionic surfactants were applied as pore-formers as well. The effect of pore-formers concentration on the in vitro release of diltiazem was also studied. The formulations were compared based on four comparative parameters, namely, total drug released after 24 h (D24 h), lag-time (tL), squared correlation coefficient of zero order equation (RSQzero) and mean percent deviation from zero order kinetic (MPDzero). Results of scanning electron microscopy studies exhibited formation of pores in the membrane from where the drug release occurred. It was revealed that drug release rate was directly proportional to the concentration of the pore-formers. The value of D24 h in the formulations containing Tween 80 (10%) and Brij 35 (5%) were found to be more than 94.9%, and drug release followed zero order kinetic (RSQzero > 0.99 and MPDzero < 8%) with acceptable tL (lower than 1 h). PMID:23763379

  16. Design Factors for Applying Cryogen Storage and Delivery Technology to Solar Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    1996-01-01

    Thermodynamic Vent System (TVS) and Multilayer Insulation (MLI) technology, originally developed for long term storage of cryogen propellants in microgravity, is ideally suited for propellant storage and delivery systems for solar thermal propulsion. With this technology the heat-induced pressure rise in the tank provides the propellant delivery pressure without the need for an auxiliary pressurant system, and propellant delivery is used to remove the excess heat to control tank pressure. The factors to consider in designing such a balanced system, are presented. An example of a minimum system design is presented along with examples of laboratory-tested hardware.

  17. Quality-by-design based development of a self-microemulsifying drug delivery system to reduce the effect of food on Nelfinavir mesylate.

    PubMed

    Kamboj, Sunil; Rana, Vikas

    2016-03-30

    Poor aqueous solubility and moderate permeability of Nelfinavir mesylate (NFM) leads to high variability in absorption after oral administration. To improve the solubility and bioavailability of NFM, the self microemulsifying drug delivery system (SMEDDS) was developed. For this purpose, Quality by design (QbD) approach employing D-optimal mixture design was used to prepare SMEDDS of NFM. Further, the software generated numerically optimized SMEDDS were developed by utilizing desirability function. Maisine 35-1, Tween 80, and Transcutol HP were identified as oil, surfactant, and co-surfactant that had best solubility for NFM. Ternary phase diagrams were plotted to identify the self-emulsification region. Dissolution of putative NFM in simulated fasted or fed small intestinal conditions, respectively, predicted that there is a positive food effect. However, NFM loaded SMEDDS showed absence of food effect with no significant difference in dissolution performance either in Fasted or fed state simulated intestinal fluid (FaSSIF or FeSSIF) biorelevent dissolution media. The prepared SMEDDS were thermodynamically stable with droplet size (121 nm), poly dispersity index (PDI) (0.198) and emulsification time (<1 min). Transmission electron microscopy (TEM) analysis confirmed the spherical shape of the reconstituted SMEDDS droplets. The ex vivo performance revealed 4.57 fold enhancement in the apparent permeability of NFM as compared to NFM suspension. The animal pharmacokinetic analysis in New Zealand strain rabbits indicated food effect on pure NFM suspension. However, absence of food effect and 3.5-3.6 fold enhancement in the oral bioavailability was observed when NFM was formulated into SMEDDS. Thus, it could be envisaged that development of SMEDDS formulation of NFM could be one of the best alternative to enhance oral bioavailability of NFM. PMID:26854426

  18. Design of a peptide-based vector, PepFect6, for efficient delivery of siRNA in cell culture and systemically in vivo

    PubMed Central

    EL Andaloussi, Samir; Lehto, Taavi; Mäger, Imre; Rosenthal-Aizman, Katri; Oprea, Iulian I.; Simonson, Oscar E.; Sork, Helena; Ezzat, Kariem; Copolovici, Dana M.; Kurrikoff, Kaido; Viola, Joana R.; Zaghloul, Eman M.; Sillard, Rannar; Johansson, Henrik J.; Said Hassane, Fatouma; Guterstam, Peter; Suhorutšenko, Julia; Moreno, Pedro M. D.; Oskolkov, Nikita; Hälldin, Jonas; Tedebark, Ulf; Metspalu, Andres; Lebleu, Bernard; Lehtiö, Janne; Smith, C. I. Edvard; Langel, Ülo

    2011-01-01

    While small interfering RNAs (siRNAs) have been rapidly appreciated to silence genes, efficient and non-toxic vectors for primary cells and for systemic in vivo delivery are lacking. Several siRNA-delivery vehicles, including cell-penetrating peptides (CPPs), have been developed but their utility is often restricted by entrapment following endocytosis. Hence, developing CPPs that promote endosomal escape is a prerequisite for successful siRNA implementation. We here present a novel CPP, PepFect 6 (PF6), comprising the previously reported stearyl-TP10 peptide, having pH titratable trifluoromethylquinoline moieties covalently incorporated to facilitate endosomal release. Stable PF6/siRNA nanoparticles enter entire cell populations and rapidly promote endosomal escape, resulting in robust RNAi responses in various cell types (including primary cells), with minimal associated transcriptomic or proteomic changes. Furthermore, PF6-mediated delivery is independent of cell confluence and, in most cases, not significantly hampered by serum proteins. Finally, these nanoparticles promote strong RNAi responses in different organs following systemic delivery in mice without any associated toxicity. Strikingly, similar knockdown in liver is achieved by PF6/siRNA nanoparticles and siRNA injected by hydrodynamic infusion, a golden standard technique for liver transfection. These results imply that the peptide, in addition to having utility for RNAi screens in vitro, displays therapeutic potential. PMID:21245043

  19. Alternative delivery systems in rural areas.

    PubMed Central

    Christianson, J B

    1989-01-01

    Alternative delivery systems, such as HMOs, PPOs, and primary care case-management programs, have a long history in rural America despite significant impediments to their development. However, little is known about the effect of these systems on rural communities and their medical care delivery systems. Existing studies, which focus on rural HMOs, are qualitative in nature and generally are directed at identifying factors that facilitate or retard HMO development. Despite their limitations, the studies do raise a variety of issues deserving of quantitative analysis. Research is now needed that (1) investigates the effect of rural alternative delivery systems on the cost and quality of care received by rural residents, (2) assesses the effectiveness of different mechanisms used by these systems to contain costs, (3) estimates the effect of alternative delivery systems on rural providers, (4) determines the extent to which the presence or absence of alternative delivery systems influences physician decisions to locate in rural areas, (5) identifies factors that are important in consumer decisions to enroll or not enroll in a rural alternative delivery system, and (6) analyzes the diffusion patterns of these systems in rural areas. PMID:2645250

  20. WEDDS: The WITS Encrypted Data Delivery System

    NASA Technical Reports Server (NTRS)

    Norris, J.; Backes, P.

    1999-01-01

    WEDDS, the WITS Encrypted Data Delivery System, is a framework for supporting distributed mission operations by automatically transferring sensitive mission data in a secure and efficient manner to and from remote mission participants over the internet.

  1. Silk-based delivery systems of bioactive molecules

    PubMed Central

    Numata, Keiji; Kaplan, David L

    2010-01-01

    Silks are biodegradable, biocompatible, self-assemblying proteins that can also be tailored via genetic engineering to contain specific chemical features, offering utility for drug and gene delivery. Silkworm silk has been used in biomedical sutures for decades and has recently achieved Food and Drug Administration approval for expanded biomaterials device utility. With the diversity and control of size, structure and chemistry, modified or recombinant silk proteins can be designed and utilized in various biomedical application, such as for the delivery of bioactive molecules. This review focuses on the biosynthesis and applications of silk-based multi-block copolymer systems and related silk protein drug delivery systems. The utility of these systems for the delivery of small molecule drugs, proteins and genes are reviewed. PMID:20298729

  2. A telemedicine health care delivery system

    NASA Technical Reports Server (NTRS)

    Sanders, Jay H.

    1991-01-01

    The Interactive Telemedicine Systems (ITS) system was specifically developed to address the ever widening gap between our medical care expertise and our medical care delivery system. The frustrating reality is that as our knowledge of how to diagnose and treat medical conditions has continued to advance, the system to deliver that care has remained in an embryonic stage. This has resulted in millions of people being denied their most basic health care needs. Telemedicine utilizes an interactive video system integrated with biomedical telemetry that allows a physician at a base station specialty medical complex or teaching hospital to examine and treat a patient at multiple satellite locations, such as rural hospitals, ambulatory health centers, correctional institutions, facilities caring for the elderly, community hospital emergency departments, or international health facilities. Based on the interactive nature of the system design, the consulting physician at the base station can do a complete history and physical examination, as if the patient at the satellite site was sitting in the physician's office. This system is described.

  3. Cyclodextrins in delivery systems: Applications

    PubMed Central

    Tiwari, Gaurav; Tiwari, Ruchi; Rai, Awani K.

    2010-01-01

    Cyclodextrins (CDs) are a family of cyclic oligosaccharides with a hydrophilic outer surface and a lipophilic central cavity. CD molecules are relatively large with a number of hydrogen donors and acceptors and, thus in general, they do not permeate lipophilic membranes. In the pharmaceutical industry, CDs have mainly been used as complexing agents to increase aqueous solubility of poorly soluble drugs and to increase their bioavailability and stability. CDs are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current CD-based therapeutics is described and possible future applications are discussed. CD-containing polymers are reviewed and their use in drug delivery is presented. Of specific interest is the use of CD-containing polymers to provide unique capabilities for the delivery of nucleic acids. Studies in both humans and animals have shown that CDs can be used to improve drug delivery from almost any type of drug formulation. Currently, there are approximately 30 different pharmaceutical products worldwide containing drug/CD complexes in the market. PMID:21814436

  4. Engaging Faculty in Telecommunications-Based Instructional Delivery Systems.

    ERIC Educational Resources Information Center

    Swalec, John J.

    In the design and development of telecommunications-based instructional delivery systems, attention to faculty involvement and training is often overlooked until the system is operational. The Waubonsee Telecommunications Instructional Consortium (TIC), in Illinois, is one network that benefited from early faculty input. Even before the first…

  5. Central composite design for the formulation and optimization of a multi-unit potential colonic drug delivery system of budesonide for ulcerative colitis.

    PubMed

    Patel, Nirav V; Patel, Jayvadan K; Shah, Shreeraj H; Patel, Jagruti N

    2011-02-01

    Budesonide is a potent glucocorticoid with high affinity for the glucocorticoid receptor, which is used for the treatment of inflammatory bowel diseases. Current oral formulations of budesonide present low efficacy against ulcerative colitis because of the premature drug release in the upper part of the gastrointestinal tract. The objective of this study was to develop a colon specific delivery system for budesonide to increase the efficacy in the treatment of ulcerative colitis using a statistical procedure. Pellets were prepared by powder layering of budesonide on nonpareils (0.5-0.6 mm) in a coating pan. Drug-layered pellets were coated with an inner layer of a combination of Eudragit RL PO and RS PO and an outer layer of Eudragit FS in a fluidized-bed apparatus. Central composite design was used to study the effect of three independent variables. The independent variables selected were amount of Eudragit FS outer coating (X1), proportion of Eudragit RL PO in the inner coating (X2), amount of Eudragit RL PO-RS PO inner coating (X3). Fifteen batches were prepared and evaluated for amount of drug released in 6 h (Y1), amount of drug released in 12h (Y2). The proportion of the more hydrophilic polymer Eudragit RL PO had the most significant effect on drug release - higher proportion gave faster release; the amount of inner and outer coat did not have a significant effect on the rate of drug release at either 6 or 12 h in the range studied. The computer optimization process and contour plots predicted the levels of independent variables X1, X2, and X3 (0.79, 0.69 and 0.35 respectively), for colon targeting. PMID:21434575

  6. Planetary Regolith Delivery Systems for ISRU

    NASA Technical Reports Server (NTRS)

    Mantovani, James G.; Townsend, Ivan I., III

    2012-01-01

    The challenges associated with collecting regolith on a planetary surface and delivering it to an in-situ resource utilization system differ significantly from similar activities conducted on Earth. Since system maintenance on a planetary body can be difficult or impossible to do, high reliability and service life are expected of a regolith delivery system. Mission costs impose upper limits on power and mass. The regolith delivery system must provide a leak-tight interface between the near-vacuum planetary surface and the pressurized ISRU system. Regolith delivery in amounts ranging from a few grams to tens of kilograms may be required. Finally, the spent regolith must be removed from the ISRU chamber and returned to the planetary environment via dust tolerant valves capable of operating and sealing over a large temperature range. This paper will describe pneumatic and auger regolith transfer systems that have already been field tested for ISRU, and discuss other systems that await future field testing.

  7. Programmable nanomedicine: synergistic and sequential drug delivery systems

    NASA Astrophysics Data System (ADS)

    Pacardo, Dennis B.; Ligler, Frances S.; Gu, Zhen

    2015-02-01

    Recent developments in nanomedicine for the cancer therapy have enabled programmable delivery of therapeutics by exploiting the stimuli-responsive properties of nanocarriers. These therapeutic systems were designed with the relevant chemical and physical properties that respond to different triggers for enhanced anticancer efficacy, including the reduced development of drug-resistance, lower therapeutic dose, site-specific transport, and spatiotemporally controlled release. This minireview discusses the current advances in programmable nanocarriers for cancer therapy with particular emphasis on synergistic and sequential drug delivery systems.

  8. Renewable energy delivery systems and methods

    DOEpatents

    Walker, Howard Andrew

    2013-12-10

    A system, method and/or apparatus for the delivery of energy at a site, at least a portion of the energy being delivered by at least one or more of a plurality of renewable energy technologies, the system and method including calculating the load required by the site for the period; calculating the amount of renewable energy for the period, including obtaining a capacity and a percentage of the period for the renewable energy to be delivered; comparing the total load to the renewable energy available; and, implementing one or both of additional and alternative renewable energy sources for delivery of energy to the site.

  9. Deep Space Systems Technology Program Future Deliveries

    NASA Technical Reports Server (NTRS)

    Salvo, Christopher G.; Keuneke, Matthew S.

    2000-01-01

    NASA is in a period of frequent launches of low cost deep space missions with challenging performance needs. The modest budgets of these missions make it impossible for each to develop its own technology, therefore, efficient and effective development and insertion of technology for these missions must be approached at a higher level than has been done in the past. The Deep Space Systems Technology Program (DSST), often referred to as X2000, has been formed to address this need. The program is divided into a series of "Deliveries" that develop and demonstrate a set of spacecraft system capabilities with broad applicability for use by multiple missions. The First Delivery Project, to be completed in 2001, will provide a one MRAD-tolerant flight computer, power switching electronics, efficient radioisotope power source, and a transponder with services at 8.4 GHz and 32 GHz bands. Plans call for a Second Delivery in late 2003 to enable complete deep space systems in the 10 to 50 kg class, and a Third Delivery built around Systems on a Chip (extreme levels of electronic and microsystems integration) around 2006. Formulation of Future Deliveries (past the First Delivery) is ongoing and includes plans for such developments as highly miniaturized digital/analog/power electronics, optical communications, multifunctional structures, miniature lightweight propulsion, advanced thermal control techniques, highly efficient radioisotope power sources, and a unified flight ground software architecture to support the needs of future highly intelligent space systems. All developments are targeted at broad applicability and reuse, and will be commercialized within the US.

  10. Brain drug delivery systems for neurodegenerative disorders.

    PubMed

    Garbayo, E; Ansorena, E; Blanco-Prieto, M J

    2012-09-01

    Neurodegenerative disorders (NDs) are rapidly increasing as population ages. However, successful treatments for NDs have so far been limited and drug delivery to the brain remains one of the major challenges to overcome. There has recently been growing interest in the development of drug delivery systems (DDS) for local or systemic brain administration. DDS are able to improve the pharmacological and therapeutic properties of conventional drugs and reduce their side effects. The present review provides a concise overview of the recent advances made in the field of brain drug delivery for treating neurodegenerative disorders. Examples include polymeric micro and nanoparticles, lipidic nanoparticles, pegylated liposomes, microemulsions and nanogels that have been tested in experimental models of Parkinson's, Alzheimer's and Huntington's disease. Overall, the results reviewed here show that DDS have great potential for NDs treatment. PMID:23016644

  11. Importance of dual delivery systems for bone tissue engineering.

    PubMed

    Farokhi, Mehdi; Mottaghitalab, Fatemeh; Shokrgozar, Mohammad Ali; Ou, Keng-Liang; Mao, Chuanbin; Hosseinkhani, Hossein

    2016-03-10

    Bone formation is a complex process that requires concerted function of multiple growth factors. For this, it is essential to design a delivery system with the ability to load multiple growth factors in order to mimic the natural microenvironment for bone tissue formation. However, the short half-lives of growth factors, their relatively large size, slow tissue penetration, and high toxicity suggest that conventional routes of administration are unlikely to be effective. Therefore, it seems that using multiple bioactive factors in different delivery systems can develop new strategies for improving bone tissue regeneration. Combination of these factors along with biomaterials that permit tunable release profiles would help to achieve truly spatiotemporal regulation during delivery. This review summarizes the various dual-control release systems that are used for bone tissue engineering. PMID:26805518

  12. Niosomes: a controlled and novel drug delivery system.

    PubMed

    Rajera, Rampal; Nagpal, Kalpana; Singh, Shailendra Kumar; Mishra, Dina Nath

    2011-01-01

    During the past decade formulation of vesicles as a tool to improve drug delivery, has created a lot of interest amongst the scientist working in the area of drug delivery systems. Vesicular system such as liposomes, niosomes, transferosomes, pharmacosomes and ethosomes provide an alternative to improve the drug delivery. Niosomes play an important role owing to their nonionic properties, in such drug delivery system. Design and development of novel drug delivery system (NDDS) has two prerequisites. First, it should deliver the drug in accordance with a predetermined rate and second it should release therapeutically effective amount of drug at the site of action. Conventional dosage forms are unable to meet these requisites. Niosomes are essentially non-ionic surfactant based multilamellar or unilamellar vesicles in which an aqueous solution of solute is entirely enclosed by a membrane resulting from the organization of surfactant macromolecules as bilayer. Niosomes are formed on hydration of non-ionic surfactant film which eventually hydrates imbibing or encapsulating the hydrating aqueous solution. The main aim of development of niosomes is to control the release of drug in a sustained way, modification of distribution profile of drug and for targeting the drug to the specific body site. This paper deals with composition, characterization/evaluation, merits, demerits and applications of niosomes. PMID:21719996

  13. Local arterial wall drug delivery using balloon catheter system.

    PubMed

    Tesfamariam, Belay

    2016-09-28

    Balloon-based drug delivery systems allow localized application of drugs to a vascular segment to reduce neointimal hyperplasia and restenosis. Drugs are coated onto balloons using excipients as drug carriers to facilitate adherence and release of drug during balloon inflation. Drug-coated balloon delivery system is characterized by a rapid drug transfer that achieves high drug concentration along the vessel wall surface, intended to correspond to the balloon dilation-induced vascular injury and healing processes. The balloon catheter system allows homogenous drug delivery to the vessel wall, such that the drug release per unit surface area is kept constant along balloons of different lengths. Optimization of the balloon coating matrix is essential for efficient drug transfer and tissue retention until the artery remodels to a normal set point. Challenges in the development of balloon-based drug delivery to the arterial wall include finding suitable excipients for drug formulation to enable drug release to a targeted lesion site effectively, maintain coating integrity during transit, prolong tissue retention and reduce particulate generation. This review highlights various factors involved in the successful design of balloon-based delivery systems, including drug release kinetics, matrix coating transfer, transmural drug partitioning, dissolution rate and release of unbound active drug. PMID:27473765

  14. Transferosomes - A vesicular transdermal delivery system for enhanced drug permeation.

    PubMed

    Rajan, Reshmy; Jose, Shoma; Mukund, V P Biju; Vasudevan, Deepa T

    2011-07-01

    Transdermal administration of drugs is generally limited by the barrier function of the skin. Vesicular systems are one of the most controversial methods for transdermal delivery of active substances. The interest in designing transdermal delivery systems was relaunched after the discovery of elastic vesicles like transferosomes, ethosomes, cubosomes, phytosomes, etc. This paper presents the composition, mechanisms of penetration, manufacturing and characterization methods of transferosomes as transdermal delivery systems of active substances. For a drug to be absorbed and distributed into organs and tissues and eliminated from the body, it must pass through one or more biological membranes/barriers at various locations. Such a movement of drug across the membrane is called as drug transport. For the drugs to be delivered to the body, they should cross the membranous barrier. The concept of these delivery systems was designed in an attempt to concentrate the drug in the tissues of interest, while reducing the amount of drug in the remaining tissues. Hence, surrounding tissues are not affected by the drug. In addition, loss of drug does not happen due to localization of drug, leading to get maximum efficacy of the medication. Therefore, the phospholipid based carrier systems are of considerable interest in this era. PMID:22171309

  15. Transferosomes - A vesicular transdermal delivery system for enhanced drug permeation

    PubMed Central

    Rajan, Reshmy; Jose, Shoma; Mukund, V. P. Biju; Vasudevan, Deepa T.

    2011-01-01

    Transdermal administration of drugs is generally limited by the barrier function of the skin. Vesicular systems are one of the most controversial methods for transdermal delivery of active substances. The interest in designing transdermal delivery systems was relaunched after the discovery of elastic vesicles like transferosomes, ethosomes, cubosomes, phytosomes, etc. This paper presents the composition, mechanisms of penetration, manufacturing and characterization methods of transferosomes as transdermal delivery systems of active substances. For a drug to be absorbed and distributed into organs and tissues and eliminated from the body, it must pass through one or more biological membranes/barriers at various locations. Such a movement of drug across the membrane is called as drug transport. For the drugs to be delivered to the body, they should cross the membranous barrier. The concept of these delivery systems was designed in an attempt to concentrate the drug in the tissues of interest, while reducing the amount of drug in the remaining tissues. Hence, surrounding tissues are not affected by the drug. In addition, loss of drug does not happen due to localization of drug, leading to get maximum efficacy of the medication. Therefore, the phospholipid based carrier systems are of considerable interest in this era. PMID:22171309

  16. Marine Origin Polysaccharides in Drug Delivery Systems.

    PubMed

    Cardoso, Matias J; Costa, Rui R; Mano, João F

    2016-02-01

    Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications. Marine polysaccharides are among the most abundant materials in the seas, which contributes to a decrease of the extraction costs, besides their solubility behavior in aqueous solvents and extraction media, and their interaction with other biocompounds. Polysaccharides such as alginate, carrageenan and fucoidan can be extracted from algae, whereas chitosan and hyaluronan can be obtained from animal sources. Most marine polysaccharides have important biological properties such as biocompatibility, biodegradability, and anti-inflammatory activity, as well as adhesive and antimicrobial actions. Moreover, they can be modified in order to allow processing them into various shapes and sizes and may exhibit response dependence to external stimuli, such as pH and temperature. Due to these properties, these biomaterials have been studied as raw material for the construction of carrier devices for drugs, including particles, capsules and hydrogels. The devices are designed to achieve a controlled release of therapeutic agents in an attempt to fight against serious diseases, and to be used in advanced therapies, such as gene delivery or regenerative medicine. PMID:26861358

  17. Marine Origin Polysaccharides in Drug Delivery Systems

    PubMed Central

    Cardoso, Matias J.; Costa, Rui R.; Mano, João F.

    2016-01-01

    Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications. Marine polysaccharides are among the most abundant materials in the seas, which contributes to a decrease of the extraction costs, besides their solubility behavior in aqueous solvents and extraction media, and their interaction with other biocompounds. Polysaccharides such as alginate, carrageenan and fucoidan can be extracted from algae, whereas chitosan and hyaluronan can be obtained from animal sources. Most marine polysaccharides have important biological properties such as biocompatibility, biodegradability, and anti-inflammatory activity, as well as adhesive and antimicrobial actions. Moreover, they can be modified in order to allow processing them into various shapes and sizes and may exhibit response dependence to external stimuli, such as pH and temperature. Due to these properties, these biomaterials have been studied as raw material for the construction of carrier devices for drugs, including particles, capsules and hydrogels. The devices are designed to achieve a controlled release of therapeutic agents in an attempt to fight against serious diseases, and to be used in advanced therapies, such as gene delivery or regenerative medicine. PMID:26861358

  18. Smart surface-enhanced Raman scattering traceable drug delivery systems.

    PubMed

    Liu, Lei; Tang, Yonghong; Dai, Sheng; Kleitz, Freddy; Qiao, Shi Zhang

    2016-07-01

    A novel smart nanoparticle-based system has been developed for tracking intracellular drug delivery through surface-enhanced Raman scattering (SERS). This new drug delivery system (DDS) shows targeted cytotoxicity towards cancer cells via pH-cleavable covalent carboxylic hydrazone links and the SERS tracing capability based on gold@silica nanocarriers. Doxorubicin, as a model anticancer drug, was employed to compare SERS with conventional fluorescence tracing approaches. It is evident that SERS demonstrates higher sensitivity and resolution, revealing intracellular details, as the strengths of the original Raman signals can be amplified by SERS. Importantly, non-destructive SERS will provide the designed DDS with great autonomy and potential to study the dynamic procedures of non-fluorescent drug delivery into living cells. PMID:27297745

  19. Human Services Course Delivery Systems.

    ERIC Educational Resources Information Center

    Soong, Robert K.; And Others

    This paper deals with various teaching methods and techniques currently is use in junior colleges in the Chicago area including traditional as well as innovative methods. The basic assumption is that teaching and learning are both essential aspects of the same system. The human services field is defined as encompassing the basic area of social…

  20. Systemic delivery of artemether by dissolving microneedles.

    PubMed

    Qiu, Yuqin; Li, Chun; Zhang, Suohui; Yang, Guozhong; He, Meilin; Gao, Yunhua

    2016-07-11

    Dissolving microneedles (DMNs) based transdermal delivery is an attractive drug delivery approach with minimal invasion. However, it is still challenging to load poorly water-soluble drugs in DMNs for systemic delivery. The aim of the study was to develop DMNs loaded with artemether (ARM) as a model drug, to enable efficient drug penetration through skin for systemic absorption and distribution. The micro-conduits created by microneedles were imaged by confocal laser scanning microscopy (CLSM), and the insertion depth was suggested to be about 270μm. The maximum amount of ARM delivered into skin was 72.67±2.69% of the initial dose loaded on DMNs preparation. Pharmacokinetics study in rats indicated a dose-dependent profile of plasma ARM concentrations, after ARM-loaded DMNs treatment. In contrast to intramuscular injection, DMNs application resulted in lower peak plasma levels, but higher plasma ARM concentration at 8h after administration. There were no significant difference in area under the curve and bioavailability between DMNs group and intramuscular group (P>0.05). Pharmacodynamics studies performed in collagen-induced arthritis (CIA) rats showed that ARM-loaded DMNs could reverse paw edema, similar to ARM intramuscular injection. In conclusion, developed DMNs provided a potential minimally invasive route for systemic delivery of poorly water-soluble drugs. PMID:27150946

  1. Integrated delivery systems focus on service delivery after capitation efforts stall.

    PubMed

    2005-03-01

    Integrated delivery systems focus on service delivery after capitation efforts stall. Integrated delivery systems are going through changes that are focusing the provider organizations more on delivering care than managing risk, says Dean C. Coddington, one of the leading researchers into capitated organizations and a senior consultant with McManis Consulting in Denver. PMID:15889632

  2. Kraft black liquor delivery systems

    SciTech Connect

    Adams, T.N.; Empie, H.L.; Obuskovic, N.; Spielbauer, T.M.

    1990-02-01

    Improvement of spray nozzles for black liquor injection into kraft recovery furnaces is expected to result from obtaining a controlled, well-defined droplet size distribution. Work this year has centered on defining the capabilities of commercial black liquor nozzles currently in use. Considerations of the observed mechanism of droplet formation suggest a major revision is needed in the theory of how droplets form from these nozzles. High resolution, high sensitivity video has been shown to be superior to flash x-ray as a technique for measuring the droplet size distribution as well as the formation history. An environmentally sound spray facility capable of spraying black liquor at temperatures up to normal firing conditions is being constructed before data acquisition continues. Preliminary correlations have been developed between liquor properties, nozzle design, and droplet size. Three aspects of nozzle design have been investigated: droplet size distribution, fluid sheet thickness, and flow and pressure drop characteristics. The standard deviation about the median droplet size for black liquor is nearly the same as the for a wide variety of other fluids and nozzle types. Preliminary correlation for fluid sheet thickness on the plate of a splashplate nozzle show the strong similarities of black liquor to other fluids. The flow and pressure drop characteristic of black liquor nozzle, follow a simple two-term relationship similar to other flow devices. This means that in routine mill operation of black liquor nozzles only the fluid acceleration in the nozzle is important, viscous losses are quiet small. 21 refs., 53 figs., 10 tabs.

  3. Smart surface-enhanced Raman scattering traceable drug delivery systems

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Tang, Yonghong; Dai, Sheng; Kleitz, Freddy; Qiao, Shi Zhang

    2016-06-01

    A novel smart nanoparticle-based system has been developed for tracking intracellular drug delivery through surface-enhanced Raman scattering (SERS). This new drug delivery system (DDS) shows targeted cytotoxicity towards cancer cells via pH-cleavable covalent carboxylic hydrazone links and the SERS tracing capability based on gold@silica nanocarriers. Doxorubicin, as a model anticancer drug, was employed to compare SERS with conventional fluorescence tracing approaches. It is evident that SERS demonstrates higher sensitivity and resolution, revealing intracellular details, as the strengths of the original Raman signals can be amplified by SERS. Importantly, non-destructive SERS will provide the designed DDS with great autonomy and potential to study the dynamic procedures of non-fluorescent drug delivery into living cells.A novel smart nanoparticle-based system has been developed for tracking intracellular drug delivery through surface-enhanced Raman scattering (SERS). This new drug delivery system (DDS) shows targeted cytotoxicity towards cancer cells via pH-cleavable covalent carboxylic hydrazone links and the SERS tracing capability based on gold@silica nanocarriers. Doxorubicin, as a model anticancer drug, was employed to compare SERS with conventional fluorescence tracing approaches. It is evident that SERS demonstrates higher sensitivity and resolution, revealing intracellular details, as the strengths of the original Raman signals can be amplified by SERS. Importantly, non-destructive SERS will provide the designed DDS with great autonomy and potential to study the dynamic procedures of non-fluorescent drug delivery into living cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03869g

  4. Chitosan Microspheres in Novel Drug Delivery Systems

    PubMed Central

    Mitra, Analava; Dey, Baishakhi

    2011-01-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. PMID:22707817

  5. Challenges in media delivery systems and servers

    NASA Astrophysics Data System (ADS)

    Swaminathan, Viswanathan

    2005-03-01

    Although multimedia compression formats and protocols to stream such content have been around for a long time, there has been limited success in the adoption of open standards for streaming over IP (Internet Protocol) networks. The elements of such an end-to-end system will be introduced outlining the responsibilities of each element. The technical and financial challenges in building a viable multimedia streaming end-to-end system will be analyzed in detail in this paper outlining some solutions and areas for further research. Also, recent migration to IP in the backend video delivery network infrastructures have made it possible to use IP based media streaming solutions in non-IP last mile access networks like cable and wireless networks in addition to the DSL networks. The advantages of using IP streaming solutions in such networks will be outlined. However, there is a different set of challenges posed by such applications. The real time constraints are acute in each element of the media delivery end-to-end system. Meeting these real time constraints in general purpose non real time server systems is quite demanding. Quality of service, resource management, session management, fail-over, reliability, and cost are some important but challenging requirements in such systems. These will also be analyzed with suggested solutions. Content protection and rights management requirements are also very challenging for open standards based multimedia delivery systems. Interoperability unfortunately interferes with security in most of the current day systems. Some approaches to solve the interoperability problems will also be presented. The requirements, challenges, and possible solutions for delivering broadcast, on demand, and interactive video delivery applications for IP based media streaming systems will be analyzed in detail.

  6. Structural design principles for delivery of bioactive components in nutraceuticals and functional foods.

    PubMed

    McClements, David Julian; Decker, Eric Andrew; Park, Yeonhwa; Weiss, Jochen

    2009-06-01

    There have been major advances in the design and fabrication of structured delivery systems for the encapsulation of nutraceutical and functional food components. A wide variety of delivery systems is now available, each with its own advantages and disadvantages for particular applications. This review begins by discussing some of the major nutraceutical and functional food components that need to be delivered and highlights the main limitations to their current utilization within the food industry. It then discusses the principles underpinning the rational design of structured delivery systems: the structural characteristics of the building blocks; the nature of the forces holding these building blocks together; and, the different ways of assembling these building blocks into structured delivery systems. Finally, we review the major types of structured delivery systems that are currently available to food scientists: lipid-based (simple, multiple, multilayer, and solid lipid particle emulsions); surfactant-based (simple micelles, mixed micelles, vesicles, and microemulsions) and biopolymer-based (soluble complexes, coacervates, hydrogel droplets, and particles). For each type of delivery system we describe its preparation, properties, advantages, and limitations. PMID:19484636

  7. Design of an implantable device for ocular drug delivery.

    PubMed

    Lee, Jae-Hwan; Pidaparti, Ramana M; Atkinson, Gary M; Moorthy, Ramana S

    2012-01-01

    Ocular diseases, such as, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa require drug management in order to prevent blindness and affecting million of adults in USA and worldwide. There is an increasing need to develop devices for drug delivery to address ocular diseases. This study focuses on the design, simulation, and development of an implantable ocular drug delivery device consisting of micro-/nanochannels embedded between top and bottom covers with a drug reservoir made from polydimethylsiloxane (PDMS) which is silicon-based organic and biodegradable polymer. Several simulations were carried out with six different micro-channel configurations in order to see the feasibility for ocular drug delivery applications. Based on the results obtained, channel design of osmotic I and osmotic II satisfied the diffusion rates required for ocular drug delivery. Finally, a prototype illustrating the three components of the drug delivery design is presented. In the future, the device will be tested for its functionality and diffusion characteristics. PMID:22919500

  8. Design Education Online: Learning Delivery and Evaluation

    ERIC Educational Resources Information Center

    Park, Ji Yong

    2011-01-01

    Online learning has been recognised as an effective pedagogical method and tool, and is broadly integrated into various types of teaching and learning strategies in higher education. In practice, the use of Virtual Learning Environment (VLE) in higher education has become an integral strategy for quality education. The field of design education,…

  9. Drug Design, Development, and Delivery: An Interdisciplinary Course on Pharmaceuticals

    ERIC Educational Resources Information Center

    Prausnitz, Mark R.; Bommarius, Andreas S.

    2011-01-01

    We developed a new interdisciplinary course on pharmaceuticals to address needs of undergraduate and graduate students in chemical engineering and other departments. This course introduces drug design, development, and delivery in an integrated fashion that provides scientific depth in context with broader impacts in business, policy, and ethics.…

  10. Viability, Advantages and Design Methodologies of M-Learning Delivery

    ERIC Educational Resources Information Center

    Zabel, Todd W.

    2010-01-01

    The purpose of this study was to examine the viability and principle design methodologies of Mobile Learning models in developing regions. Demographic and market studies were utilized to determine the viability of M-Learning delivery as well as best uses for such technologies and methods given socioeconomic and political conditions within the…

  11. Lessons Learned from the Node 1 Sample Delivery Subsystem Design

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2007-01-01

    This paper will provide an overview of the International Space Station (ISS) Environmental Control and Life Support (ECLS) design of the Node 1 Sample Delivery Subsystem (SDS) and it will document some of the lessons that have been learned to date for this part of the subsystem.

  12. Drug delivery system and breast cancer cells

    NASA Astrophysics Data System (ADS)

    Colone, Marisa; Kaliappan, Subramanian; Calcabrini, Annarica; Tortora, Mariarosaria; Cavalieri, Francesca; Stringaro, Annarita

    2016-06-01

    Recently, nanomedicine has received increasing attention for its ability to improve the efficacy of cancer therapeutics. Nanosized polymer therapeutic agents offer the advantage of prolonged circulation in the blood stream, targeting to specific sites, improved efficacy and reduced side effects. In this way, local, controlled delivery of the drug will be achieved with the advantage of a high concentration of drug release at the target site while keeping the systemic concentration of the drug low, thus reducing side effects due to bioaccumulation. Various drug delivery systems such as nanoparticles, liposomes, microparticles and implants have been demonstrated to significantly enhance the preventive/therapeutic efficacy of many drugs by increasing their bioavailability and targetability. As these carriers significantly increase the therapeutic effect of drugs, their administration would become less cost effective in the near future. The purpose of our research work is to develop a delivery system for breast cancer cells using a microvector of drugs. These results highlight the potential uses of these responsive platforms suited for biomedical and pharmaceutical applications. At the request of all authors of the paper an updated version was published on 12 July 2016. The manuscript was prepared and submitted without Dr. Francesca Cavalieri's contribution and her name was added without her consent. Her name has been removed in the updated and re-published article.

  13. Drug delivery system and breast cancer cells

    NASA Astrophysics Data System (ADS)

    Colone, Marisa; Kaliappan, Subramanian; Calcabrini, Annarica; Tortora, Mariarosaria; Cavalieri, Francesca; Stringaro, Annarita

    2016-06-01

    Recently, nanomedicine has received increasing attention for its ability to improve the efficacy of cancer therapeutics. Nanosized polymer therapeutic agents offer the advantage of prolonged circulation in the blood stream, targeting to specific sites, improved efficacy and reduced side effects. In this way, local, controlled delivery of the drug will be achieved with the advantage of a high concentration of drug release at the target site while keeping the systemic concentration of the drug low, thus reducing side effects due to bioaccumulation. Various drug delivery systems such as nanoparticles, liposomes, microparticles and implants have been demonstrated to significantly enhance the preventive/therapeutic efficacy of many drugs by increasing their bioavailability and targetability. As these carriers significantly increase the therapeutic effect of drugs, their administration would become less cost effective in the near future. The purpose of our research work is to develop a delivery system for breast cancer cells using a microvector of drugs. These results highlight the potential uses of these responsive platforms suited for biomedical and pharmaceutical applications.

  14. Recent Trends of Polymer Mediated Liposomal Gene Delivery System

    PubMed Central

    Lee, Sang-Soo; George Priya Doss, C.; Yagihara, Shin; Kim, Do-Young

    2014-01-01

    Advancement in the gene delivery system have resulted in clinical successes in gene therapy for patients with several genetic diseases, such as immunodeficiency diseases, X-linked adrenoleukodystrophy (X-ALD) blindness, thalassemia, and many more. Among various delivery systems, liposomal mediated gene delivery route is offering great promises for gene therapy. This review is an attempt to depict a portrait about the polymer based liposomal gene delivery systems and their future applications. Herein, we have discussed in detail the characteristics of liposome, importance of polymer for liposome formulation, gene delivery, and future direction of liposome based gene delivery as a whole. PMID:25250340

  15. Advances in the applications of polyhydroxyalkanoate nanoparticles for novel drug delivery system.

    PubMed

    Shrivastav, Anupama; Kim, Hae-Yeong; Kim, Young-Rok

    2013-01-01

    Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system. PMID:23984383

  16. Advances in the Applications of Polyhydroxyalkanoate Nanoparticles for Novel Drug Delivery System

    PubMed Central

    Shrivastav, Anupama; Kim, Hae-Yeong; Kim, Young-Rok

    2013-01-01

    Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system. PMID:23984383

  17. Drug Delivery Systems, CNS Protection, and the Blood Brain Barrier

    PubMed Central

    Upadhyay, Ravi Kant

    2014-01-01

    Present review highlights various drug delivery systems used for delivery of pharmaceutical agents mainly antibiotics, antineoplastic agents, neuropeptides, and other therapeutic substances through the endothelial capillaries (BBB) for CNS therapeutics. In addition, the use of ultrasound in delivery of therapeutic agents/biomolecules such as proline rich peptides, prodrugs, radiopharmaceuticals, proteins, immunoglobulins, and chimeric peptides to the target sites in deep tissue locations inside tumor sites of brain has been explained. In addition, therapeutic applications of various types of nanoparticles such as chitosan based nanomers, dendrimers, carbon nanotubes, niosomes, beta cyclodextrin carriers, cholesterol mediated cationic solid lipid nanoparticles, colloidal drug carriers, liposomes, and micelles have been discussed with their recent advancements. Emphasis has been given on the need of physiological and therapeutic optimization of existing drug delivery methods and their carriers to deliver therapeutic amount of drug into the brain for treatment of various neurological diseases and disorders. Further, strong recommendations are being made to develop nanosized drug carriers/vehicles and noninvasive therapeutic alternatives of conventional methods for better therapeutics of CNS related diseases. Hence, there is an urgent need to design nontoxic biocompatible drugs and develop noninvasive delivery methods to check posttreatment clinical fatalities in neuropatients which occur due to existing highly toxic invasive drugs and treatment methods. PMID:25136634

  18. Hypoxia Responsive Drug Delivery Systems in Tumor Therapy.

    PubMed

    Alimoradi, Houman; Matikonda, Siddharth S; Gamble, Allan B; Giles, Gregory I; Greish, Khaled

    2016-01-01

    Hypoxia is a common characteristic of solid tumors. It is mainly determined by low levels of oxygen resulting from imperfect vascular networks supplying most tumors. In an attempt to improve the present chemotherapeutic treatment and reduce associated side effects, several prodrug strategies have been introduced to achieve hypoxia-specific delivery of cytotoxic anticancer agents. With the advances in nanotechnology, novel delivery systems activated by the consequent outcomes of hypoxia have been developed. However, developing hypoxia responsive drug delivery systems (which only depend on low oxygen levels) is currently naïve. This review discusses four main hypoxia responsive delivery systems: polymeric based drug delivery systems, oxygen delivery systems combined with radiotherapy and chemotherapy, anaerobic bacteria which are used for delivery of genes to express anticancer proteins such as tumor necrosis alpha (TNF-α) and hypoxia-inducible transcription factors 1 alpha (HIF1α) responsive gene delivery systems. PMID:26898739

  19. Design and evaluation of a novel potential carrier for a hydrophilic antitumor drug: Auricularia auricular polysaccharide-chitosan nanoparticles as a delivery system for doxorubicin hydrochloride.

    PubMed

    Xiong, Wei; Li, Li; Wang, Yingying; Yu, Yibin; Wang, Shenxia; Gao, Yunyun; Liang, Yanyao; Zhang, Guogang; Pan, Weisan; Yang, Xinggang

    2016-09-10

    To improve the low loading content of hydrophilic drugs in nanodrug delivery systems, a natural watersoluble polysaccharide, Auricularia auricular polysaccharide (AAP), was extracted and purified as a vehicle for the hydrophilic drug doxorubicin hydrochloride (Dox·HCl). This involved the preparation of polyelectrolyte complexes nanoparticles (PEC NPs) using the electrostatic interaction between cationic chitosan (CS) and anionic AAP. The formation of AAP-CS-NPs was confirmed by FT-IR and TEM. It was found that Dox-loaded AAP-CS-NPs possessed a spherical morphology with average diameters of 237.6nm and 74.1% Dox·HCl encapsulation efficiency. The stability of Dox AAP-CS-NPs was examined by suspending the nanoparticles in PBS (pH 7.4) at room temperature. The particle size of the nanoparticle samples remained stable and exhibited no obvious variations in drug content after half a month. In addition, in vitro cytotoxicity studies showed that blank AAP-CS-NPs did not exhibit any cytotoxic effects, while Dox AAP-CS-NPs increased the Dox·HCl cytotoxicity against MCF-7 cells as the result of significantly increased cellular uptake, compared with free Dox·HCl. Hence, the overall results obtained suggest that AAP-CS-NPs are very effective in entrapping Dox·HCl and to penetrate into tumor cells, rendering them promising carriers for hydrophilic antitumor drugs. PMID:27424168

  20. Effects of formulation design on niacin therapeutics: mechanism of action, metabolism, and drug delivery.

    PubMed

    Cooper, Dustin L; Murrell, Derek E; Roane, David S; Harirforoosh, Sam

    2015-07-25

    Niacin is a highly effective, lipid regulating drug associated with a number of metabolically induced side effects such as prostaglandin (PG) mediated flushing and hepatic toxicity. In an attempt to reduce the development of these adverse effects, scientists have investigated differing methods of niacin delivery designed to control drug release and alter metabolism. However, despite successful formulation of various orally based capsule and tablet delivery systems, patient adherence to niacin therapy is still compromised by adverse events such as PG-induced flushing. While the primary advantage of orally dosed formulations is ease of use, alternative delivery options such as transdermal delivery or polymeric micro/nanoparticle encapsulation for oral administration have shown promise in niacin reformulation. However, the effectiveness of these alternative delivery options in reducing inimical effects of niacin and maintaining drug efficacy is still largely unknown and requires more in-depth investigation. In this paper, we present an overview of niacin applications, its metabolic pathways, and current drug delivery formulations. Focus is placed on oral immediate, sustained, and extended release niacin delivery as well as combined statin and/or prostaglandin antagonist niacin formulation. We also examine and discuss current findings involving transdermal niacin formulations and polymeric micro/nanoparticle encapsulated niacin delivery. PMID:25987211

  1. Towards more effective advanced drug delivery systems.

    PubMed

    Crommelin, Daan J A; Florence, Alexander T

    2013-09-15

    This position paper discusses progress made and to be made with so-called advanced drug delivery systems, particularly but not exclusively those in the nanometre domain. The paper has resulted from discussions with a number of international experts in the field who shared their views on aspects of the subject, from the nomenclature used for such systems, the sometimes overwrought claims made in the era of nanotechnology, the complex nature of targeting delivery systems to specific destinations in vivo, the need for setting standards for the choice and characterisation of cell lines used in in vitro studies, to attention to the manufacturability, stability and analytical profiling of systems and more relevant studies on toxicology. The historical background to the development of many systems is emphasised. So too is the stochastic nature of many of the steps to successful access to and action in targets. A lacuna in the field is the lack of availability of data on a variety of carrier systems using the same models in vitro and in vivo using standard controls. The paper asserts that greater emphasis must also be paid to the effective levels of active attained in target organs, for without such crucial data it will be difficult for many experimental systems to enter the clinic. This means the use of diagnostic/imaging technologies to monitor targeted drug delivery and stratify patient groups, identifying patients with optimum chances for successful therapy. Last, but not least, the critical importance of the development of science bases for regulatory policies, scientific platforms overseeing the field and new paradigms of financing are discussed. PMID:23415662

  2. The LITA Drill and Sample Delivery System

    NASA Astrophysics Data System (ADS)

    Paulsen, G.; Yoon, S.; Zacny, K.; Wettergreeng, D.; Cabrol, N. A.

    2013-12-01

    The Life in the Atacama (LITA) project has a goal of demonstrating autonomous roving, sample acquisition, delivery and analysis operations in Atacama, Chile. To enable the sample handling requirement, Honeybee Robotics developed a rover-deployed, rotary-percussive, autonomous drill, called the LITA Drill, capable of penetrating to ~80 cm in various formations, capturing and delivering subsurface samples to a 20 cup carousel. The carousel has a built-in capability to press the samples within each cup, and position target cups underneath instruments for analysis. The drill and sample delivery system had to have mass and power requirements consistent with a flight system. The drill weighs 12 kg and uses less than 100 watt of power to penetrate ~80 cm. The LITA Drill auger has been designed with two distinct stages. The lower part has deep and gently sloping flutes for retaining powdered sample, while the upper section has shallow and steep flutes for preventing borehole collapse and for efficient movement of cuttings and fall back material out of the hole. The drill uses the so called 'bite-sampling' approach that is samples are taken in short, 5-10 cm bites. To take the first bite, the drill is lowered onto the ground and upon drilling of the first bite it is then retracted into an auger tube. The auger with the auger tube are then lifted off the ground and positioned next to the carousel. To deposit the sample, the auger is rotated and retracted above the auger tube. The cuttings retained on the flutes are either gravity fed or are brushed off by a passive side brush into the cup. After the sample from the first bite has been deposited, the drill is lowered back into the same hole to take the next bite. This process is repeated until a target depth is reached. The bite sampling is analogous to peck drilling in the machining process where a bit is periodically retracted to clear chips. If there is some fall back into the hole once the auger has cleared the hole, this

  3. Design, synthesis, and optimization of nanostructured calcium phosphates (NanoCaPs) and natural polymer based 3-D non-viral gene delivery systems

    NASA Astrophysics Data System (ADS)

    Ko, Hsu-Feng

    Sustained delivery of therapeutic genes from a three-dimensional (3-D) scaffold and subsequent gene expression capable of triggering the regeneration of damaged tissues is a tissue engineering strategy that has been gaining increased attention. Nanostructured calcium phosphates (NanoCaPs) are biocompatible and non-toxic biomaterials. Furthermore, their efficient transfection in vitro have rendered them attractive gene delivery carriers compared to other viral- or lipid-based agents that tend to be immunogenic or cytotoxic, leading to undesirable responses when utilized above a critical threshold. However, NanoCaPs are typically characterized by variable transfection and short shelf life due to particle aggregation. A viable solution to this problem is the incorporation of NanoCaPs into 3-D scaffolds. The main objectives of this research are therefore two-fold: (1) Examination of the potential of achieving optimized transfection of NanoCaPs via anionic substitution and (2) high throughput synthesis and screening of non-viral gene delivery systems (GDS) comprised of naturally-derived polymers as scaffolds containing NanoCaPs gene carriers. Results indicated that in addition to the excellent transfection levels exhibited by NanoCaPs in vitro, an additional 20-30% increase was observed for NanoCaPs with 10-25 mol% anion substitution. In contrast, high anion substitution (>60%) yielded a drastic decline in transfection. Structural characterizations verified successful anion substitution with a noticeable increase in lattice parameters indicative of an expanded unit cell due to ionic substitution. All of the anion substituted calcium phosphates exhibited the primary phase of hydroxyapatite. For the first time, GDS composed of various concentrations of alginate (AA), fibronectin (FN), and NanoCaPs-DNA complexes were demonstrated. The presence of AA and FN was effective in immobilizing NanoCaPs and reducing the aggregation. High throughput synthesis and screening

  4. Ultrasound-mediated nail drug delivery system.

    PubMed

    Abadi, Danielle; Zderic, Vesna

    2011-12-01

    A novel ultrasound-mediated drug delivery system has been developed for treatment of a nail fungal disorder (onychomycosis) by improving delivery to the nail bed using ultrasound to increase the permeability of the nail. The slip-in device consists of ultrasound transducers and drug delivery compartments above each toenail. The device is connected to a computer, where a software interface allows users to select their preferred course of treatment. In in vitro testing, canine nails were exposed to 3 energy levels (acoustic power of 1.2 W and exposure durations of 30, 60, and 120 seconds). A stereo -microscope was used to determine how much of a drug-mimicking compound was delivered through the nail layers by measuring brightness on the cross section of each nail tested at each condition, where brightness level decreases coincide with increases in permeability. Each of the 3 energy levels tested showed statistical significance when compared to the control (P < .05) with a permeability factor of 1.3 after 30 seconds of exposure, 1.3 after 60 seconds, and 1.5 after 120 seconds, where a permeability factor of 1 shows no increase in permeability. Current treatments for onychomycosis include systemic, topical, and surgical. Even when used all together, these treatments typically take a long time to result in nail healing, thus making this ultrasound-mediated device a promising alternative. PMID:22124008

  5. THE SUPERCONDUCTION MAGNETS OF THE ILC BEAM DELIVERY SYSTEM.

    SciTech Connect

    PARKER,B.; ANEREELA, M.; ESCALLIE, J.; HE, P.; JAIN, A.; MARONE, A.; NOSOCHKOV, Y.; SERYI, A.

    2007-06-25

    The ILC Reference Design Report was completed early in February 2007. The Magnet Systems Group was formed to translate magnetic field requirements into magnet designs and cost estimates for the Reference Design. As presently configured, the ILC will have more than 13,000 magnetic elements of which more than 2300 will be based on superconducting technology. This paper will describe the major superconducting magnet needs for the ILC as presently determined by the Area Systems Groups, responsible for beam line design, working with the Magnet Systems Group. The superconducting magnet components include Main Linac quadrupoles, Positron Source undulators, Damping Ring wigglers, a complex array of Final Focus superconducting elements in the Beam Delivery System, and large superconducting solenoids in the e{sup +} and e{sup -} Sources, and the Ring to Main Linac lines.

  6. Enhancing intestinal drug solubilisation using lipid-based delivery systems.

    PubMed

    Porter, Christopher J H; Pouton, Colin W; Cuine, Jean F; Charman, William N

    2008-03-17

    Lipid-based delivery systems are finding increasing application in the oral delivery of poorly water-soluble, lipophilic drugs. Whilst lipidic dose forms may improve oral bioavailability via several mechanisms, enhancement of gastrointestinal solubilisation remains argueably the most important method of absorption enhancement. This review firstly describes the mechanistic rationale which underpins the use of lipid-based delivery systems to enhance drug solubilisation and briefly reviews the available literature describing increases in oral bioavailability after the administration of lipid solution, suspension and self-emulsifying formulations. The use of in vitro methods including dispersion tests and more complex models of in vitro lipolysis as indicators of potential in vivo performance are subsequently described, with particular focus on recent data which suggests that the digestion of surfactants present in lipid-based formulations may impact on formulation performance. Finally, a series of seven guiding principles for formulation design of lipid-based delivery systems are suggested based on an analysis of recent data generated in our laboratories and elsewhere. PMID:18155801

  7. Stimuli-Responsive Polymeric Systems for Controlled Protein and Peptide Delivery: Future Implications for Ocular Delivery.

    PubMed

    Mahlumba, Pakama; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Pillay, Viness

    2016-01-01

    Therapeutic proteins and peptides have become notable in the drug delivery arena for their compatibility with the human body as well as their high potency. However, their biocompatibility and high potency does not negate the existence of challenges resulting from physicochemical properties of proteins and peptides, including large size, short half-life, capability to provoke immune responses and susceptibility to degradation. Various delivery routes and delivery systems have been utilized to improve bioavailability, patient acceptability and reduce biodegradation. The ocular route remains of great interest, particularly for responsive delivery of macromolecules due to the anatomy and physiology of the eye that makes it a sensitive and complex environment. Research in this field is slowly gaining attention as this could be the breakthrough in ocular drug delivery of macromolecules. This work reviews stimuli-responsive polymeric delivery systems, their use in the delivery of therapeutic proteins and peptides as well as examples of proteins and peptides used in the treatment of ocular disorders. Stimuli reviewed include pH, temperature, enzymes, light, ultrasound and magnetic field. In addition, it discusses the current progress in responsive ocular drug delivery. Furthermore, it explores future prospects in the use of stimuli-responsive polymers for ocular delivery of proteins and peptides. Stimuli-responsive polymers offer great potential in improving the delivery of ocular therapeutics, therefore there is a need to consider them in order to guarantee a local, sustained and ideal delivery of ocular proteins and peptides, evading tissue invasion and systemic side-effects. PMID:27483234

  8. Modeling the Delivery Physiology of Distributed Learning Systems.

    ERIC Educational Resources Information Center

    Paquette, Gilbert; Rosca, Ioan

    2003-01-01

    Discusses instructional delivery models and their physiology in distributed learning systems. Highlights include building delivery models; types of delivery models, including distributed classroom, self-training on the Web, online training, communities of practice, and performance support systems; and actors (users) involved, including experts,…

  9. The new organization of the health care delivery system.

    PubMed

    Shortell, S M; Hull, K E

    1996-01-01

    The U.S. health care system is restructuring at a dizzying pace. In many parts of the country, managed care has moved into third-generation models emphasizing capitated payment for enrolled lives and, in the process, turning most providers and institutions into cost centers to be managed rather than generators of revenue. While the full impact of the new managed care models remains to be seen, most evidence to date suggests that it tends to reduce inpatient use, may be associated with greater use of physician services and preventive care, and appears to result in no net differences either positive or negative with regard to quality or outcomes of care in comparison with fee-for-service plans. Some patients, however, tend to be somewhat less satisfied with scheduling of appointments and the amount of time spent with providers. There is no persuasive evidence that managed care lowers the rate of growth in overall health care costs within a given market. Further, managed care performance varies considerably across the country, and the factors influencing managed care performance are not well understood. Organized delivery systems are a somewhat more recent phenomenon representing various forms of ownership and strategic alliances among hospitals, physicians, and insurers designed to provide more cost-effective care to defined populations by achieving desired levels of functional, physician-system, and clinical integration. Early evidence suggests that organized delivery systems that are more integrated have the potential to provide more accessible coordinated care across the continuum, and appear to be associated with higher levels of inpatient productivity, greater total system revenue, greater total system cash flow, and greater total system operating margin than less integrated delivery forms. Some key success factors for developing organized delivery systems have been identified. Important roles are played by organizational culture, information systems, internal

  10. Advances in Systemic siRNA Delivery

    PubMed Central

    Leng, Qixin; Woodle, Martin C; Lu, Patrick Y; Mixson, A James

    2009-01-01

    Sequence-specific gene silencing with small interfering RNA (siRNA) has transformed basic science research, and the efficacy of siRNA therapeutics toward a variety of diseases is now being evaluated in pre-clinical and clinical trials. Despite its potential value, the highly negatively charged siRNA has the classic delivery problem of requiring transport across cell membranes to the cytosol. Consequently, carrier development for siRNA delivery is one of the most important problems to solve before siRNA can achieve widespread clinical use. An assortment of non-viral carriers including liposomes, peptides, polymers, and aptamers are being evaluated for their ability to shepherd siRNA to the target tissue and cross the plasma membrane barrier into the cell. Several promising carriers with low toxicity and increased specificity for disease targets have emerged for siRNA-based therapeutics. This review will discuss non-viral approaches for siRNA therapeutics, with particular focus on synthetic carriers for in vivo systemic delivery of siRNA. PMID:20161621