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Sample records for long-acting plga microspheres

  1. The angiogenic effect of ONO-1301, a novel long-acting prostacyclin agonist loaded in PLGA microspheres prepared using different molecular weights of PLGA, in a murine sponge model.

    PubMed

    Hazekawa, Mai; Morihata, Kana; Yoshida, Miyako; Sakai, Yoshiki; Uchida, Takahiro

    2014-11-01

    The purpose of this study was to evaluate the angiogenic effect of topical application of three types of ONO-1301-loaded poly (lactide-co-glycolide) microspheres (ONO-1301 PLGA MS). ONO-1301 PLGA MS were prepared with PLGA 5010, 5020 and 5050 (with molecular weights of 10 K, 20 K and 50 K, respectively), using the solvent evaporation method. The lactide:glycolide ratio was fixed at 50:50; only the molecular weight was varied. The microspheres had an average diameter of almost 25 µm, and a loading efficiency of at least 70%. The sustained-release effect and its dependence on the molecular weight of the polymer used was confirmed in an in vitro drug-release test and by measuring subcutaneous plasma levels after administration of the three types of ONO-1301 PLGA MS to rats for 28 days. In the murine sponge model, the three types of ONO-1301 PLGA MS were administered to mice in a subcutaneously placed sponge and hemoglobin and hepatocyte growth factor (HGF) levels in the sponge were measured at predefined intervals up to 28 days. The hemoglobin and HGF levels obtained were significantly higher than those obtained after daily administration of ONO-1301 powder. Additional in vivo fluorescence imaging showed that PLGA MS remained in the sponge for 28 days. In conclusion, the three types of ONO-1301 PLGA MS prepared with PLGA three different molecular weight suppress the burst release, stimulate angiogenesis on topical application in a murine sponge model. This formulation may therefore be capable of improving the clinical picture in some types of vascular disease.

  2. Development of Risperidone PLGA Microspheres

    PubMed Central

    D'Souza, Susan; Faraj, Jabar A.; Giovagnoli, Stefano; DeLuca, Patrick P.

    2014-01-01

    The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25) were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug. PMID:24616812

  3. A reproducible accelerated in vitro release testing method for PLGA microspheres.

    PubMed

    Shen, Jie; Lee, Kyulim; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

    2016-02-10

    The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting PLGA microspheres with inner structure/porosity differences. Risperidone was chosen as a model drug. Qualitatively and quantitatively equivalent PLGA microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared risperidone microspheres was performed using the most common in vitro release methods (i.e., sample-and-separate and flow through) for this type of product. The obtained compositionally equivalent risperidone microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous risperidone microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate risperidone microsphere formulations with differences in porosity under real-time (37 °C) and accelerated (45 °C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous risperidone microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting PLGA microspheres (even with porous structures).

  4. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    PubMed

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

  5. In Vitro and In Vivo Evaluations of PLGA Microspheres Containing Nalmefene

    PubMed Central

    Xie, Xiangyang; Lin, Wen; Xing, Chuanfeng; Yang, Yanfang; Chi, Qiang; Zhang, Hui; Li, Ying; Li, Zhiping; Yang, Yang; Yang, Zhenbo; Li, Mingyuang

    2015-01-01

    Poor patient compliance, untoward reactions and unstable blood drug levels after the bolus administration are impeding the pharmacotherapy for insobriety. A long-acting preparation may address these limitations. The aim of this paper was to further investigate the in vitro characteristics and in vivo performances of nalmefene microspheres. Nalmefene was blended with poly (lactide-co-glycolide) (PLGA) to prepare the target microspheres by an O/O emulsification solvent evaporation method. The prepared microspheres exhibited a controlled release profile of nalmefene in vitro over 4 weeks, which was well fitted with a first-order model. In vitro degradation study showed that the drug release in vitro was dominated by both drug diffusion and polymer degradation mechanisms. Pharmacokinetics study indicated that the prepared microspheres could provide a relatively constant of nalmefene plasma concentration for at least one month in rats. The in vivo pharmacokinetics profile was well correlated with the in vitro drug release. Pharmacodynamics studies revealed that the drug loaded microspheres could produce a long-acting antagonism efficacy on rats. These results demonstrated the promising application of injectable PLGA microspheres containing nalmefene for the long-term treatment of alcohol dependence. PMID:25938514

  6. Prediction of dexamethasone release from PLGA microspheres prepared with polymer blends using a design of experiment approach.

    PubMed

    Gu, Bing; Burgess, Diane J

    2015-11-10

    Hydrophobic drug release from poly (lactic-co-glycolic acid) (PLGA) microspheres typically exhibits a tri-phasic profile with a burst release phase followed by a lag phase and a secondary release phase. High burst release can be associated with adverse effects and the efficacy of the formulation cannot be ensured during a long lag phase. Accordingly, the development of a long-acting microsphere product requires optimization of all drug release phases. The purpose of the current study was to investigate whether a blend of low and high molecular weight polymers can be used to reduce the burst release and eliminate/minimize the lag phase. A single emulsion solvent evaporation method was used to prepare microspheres using blends of two PLGA polymers (PLGA5050 (25 kDa) and PLGA9010 (113 kDa)). A central composite design approach was applied to investigate the effect of formulation composition on dexamethasone release from these microspheres. Mathematical models obtained from this design of experiments study were utilized to generate a design space with maximized microsphere drug loading and reduced burst release. Specifically, a drug loading close to 15% can be achieved and a burst release less than 10% when a composition of 80% PLGA9010 and 90 mg of dexamethasone is used. In order to better describe the lag phase, a heat map was generated based on dexamethasone release from the PLGA microsphere/PVA hydrogel composite coatings. Using the heat map an optimized formulation with minimum lag phase was selected. The microspheres were also characterized for particle size/size distribution, thermal properties and morphology. The particle size was demonstrated to be related to the polymer concentration and the ratio of the two polymers but not to the dexamethasone concentration.

  7. PEGylated apoptotic protein-loaded PLGA microspheres for cancer therapy

    PubMed Central

    Byeon, Hyeong Jun; Kim, Insoo; Choi, Ji Su; Lee, Eun Seong; Shin, Beom Soo; Youn, Yu Seok

    2015-01-01

    The aim of the current study was to investigate the antitumor potential of poly (D,L-lactic-co-glycolic acid) microspheres (PLGA MSs) containing polyethylene glycol (PEG)-conjugated (PEGylated) tumor necrosis factor–related apoptosis-inducing ligand (PEG-TRAIL). PEG-TRAIL PLGA MSs were prepared by using a water-in-oil-in-water double-emulsion method, and the apoptotic activities of supernatants released from the PLGA MSs at days 1, 3, and 7 were examined. The antitumor effect caused by PEG-TRAIL PLGA MSs was evaluated in pancreatic Mia Paca-2 cell-xenografted mice. PEG-TRAIL PLGA MS was found to be spherical and 14.4±1.06 μm in size, and its encapsulation efficiency was significantly greater than that of TRAIL MS (85.7%±4.1% vs 43.3%±10.9%, respectively). The PLGA MS gradually released PEG-TRAIL for 14 days, and the released PEG-TRAIL was shown to have clear apoptotic activity in Mia Paca-2 cells, whereas TRAIL released after 1 day had a negligible activity. Finally, PEG-TRAIL PLGA MS displayed remarkably greater antitumor efficacy than blank or TRAIL PLGA MS in Mia Paca-2 cell-xenografted mice in terms of tumor volume and weight, apparently due to increased stability and well-retained apoptotic activity of PEG-TRAIL in PLGA MS. We believe that this PLGA MS system, combined with PEG-TRAIL, should be considered a promising candidate for treating pancreatic cancer. PMID:25632232

  8. PEGylated apoptotic protein-loaded PLGA microspheres for cancer therapy.

    PubMed

    Byeon, Hyeong Jun; Kim, Insoo; Choi, Ji Su; Lee, Eun Seong; Shin, Beom Soo; Youn, Yu Seok

    2015-01-01

    The aim of the current study was to investigate the antitumor potential of poly (D,L-lactic-co-glycolic acid) microspheres (PLGA MSs) containing polyethylene glycol (PEG)-conjugated (PEGylated) tumor necrosis factor-related apoptosis-inducing ligand (PEG-TRAIL). PEG-TRAIL PLGA MSs were prepared by using a water-in-oil-in-water double-emulsion method, and the apoptotic activities of supernatants released from the PLGA MSs at days 1, 3, and 7 were examined. The antitumor effect caused by PEG-TRAIL PLGA MSs was evaluated in pancreatic Mia Paca-2 cell-xenografted mice. PEG-TRAIL PLGA MS was found to be spherical and 14.4±1.06 μm in size, and its encapsulation efficiency was significantly greater than that of TRAIL MS (85.7%±4.1% vs 43.3%±10.9%, respectively). The PLGA MS gradually released PEG-TRAIL for 14 days, and the released PEG-TRAIL was shown to have clear apoptotic activity in Mia Paca-2 cells, whereas TRAIL released after 1 day had a negligible activity. Finally, PEG-TRAIL PLGA MS displayed remarkably greater antitumor efficacy than blank or TRAIL PLGA MS in Mia Paca-2 cell-xenografted mice in terms of tumor volume and weight, apparently due to increased stability and well-retained apoptotic activity of PEG-TRAIL in PLGA MS. We believe that this PLGA MS system, combined with PEG-TRAIL, should be considered a promising candidate for treating pancreatic cancer.

  9. Preparation and in vivo evaluation of PCADK/PLGA microspheres for improving stability and efficacy of rhGH.

    PubMed

    Wang, Chenhui; Yu, Changhui; Liu, Jiaxin; Teng, Lesheng; Sun, Fengying; Li, Youxin

    2015-11-30

    The goal of this research is to prepare poly(cyclohexane-1,4 diyl acetone dimethylene ketal) (PCADK)/poly(D,L-lactide-co-glycolide) (PLGA) blend microspheres loaded with recombinant human growth hormone (rhGH). The effect of PCADK degradation products on the structural integrity, secondary and tertiary structure and pharmacodynamics of rhGH was evaluated by native-polyacrylamide gel electrophoresis (Native-PAGE), size-exclusion high performance liquid chromatography (SEC-HPLC), circular dichroism (CD), fluorescence spectroscopy and in hypophysectomized rat models. Compared with PLGA degradation products, rhGH was found to be more stable in the presence of PCADK degradation products. PCADK/PLGA blend microspheres were then prepared and the morphology, encapsulation efficiency, release behavior and rhGH stability were investigated. PCADK/PLGA microspheres had regular shapes and smooth surfaces when the proportion of PCADK was less than 50%. The late-releasable amount of rhGH in PCADK/PLGA microspheres was greater than that in PLGA microspheres. In addition, the PCADK/PLGA microspheres showed larger AUC and improved therapeutic effects on rats than PLGA microspheres. Furthermore, the pH inside the microspheres was detected by CLSM to explain the improved rhGH stability in the PCADK/PLGA microspheres. In conclusion, PCADK/PLGA blend microspheres showed potential to improve rhGH stability and the efficacy of sustained-release of rhGH compared with PLGA microspheres.

  10. Porous silicon oxide-PLGA composite microspheres for sustained ocular delivery of daunorubicin.

    PubMed

    Nan, Kaihui; Ma, Feiyan; Hou, Huiyuan; Freeman, William R; Sailor, Michael J; Cheng, Lingyun

    2014-08-01

    A water-soluble anthracycline antibiotic drug (daunorubicin, DNR) was loaded into oxidized porous silicon (pSiO2) microparticles and then encapsulated with a layer of polymer (poly lactide-co-glycolide, PLGA) to investigate their synergistic effects in control of DNR release. Similarly fabricated PLGA-DNR microspheres without pSiO2, and pSiO2 microparticles without PLGA were used as control particles. The composite microparticles synthesized by a solid-in-oil-in-water emulsion method have mean diameters of 52.33±16.37μm for PLGA-pSiO2_21/40-DNR and the mean diameter of 49.31±8.87μm for PLGA-pSiO2_6/20-DNR. The mean size, 26.00±8μm, of PLGA-DNR was significantly smaller, compared with the other two (P<0.0001). Optical microscopy revealed that PLGA-pSiO2-DNR microspheres contained multiple pSiO2 particles. In vitro release experiments determined that control PLGA-DNR microspheres completely released DNR within 38days and control pSiO2-DNR microparticles (with no PLGA coating) released DNR within 14days, while the PLGA-pSiO2-DNR microspheres released DNR for 74days. Temporal release profiles of DNR from PLGA-pSiO2 composite particles indicated that both PLGA and pSiO2 contribute to the sustained release of the payload. The PLGA-pSiO2 composite displayed a more constant rate of DNR release than the pSiO2 control formulation, and displayed a significantly slower release of DNR than either the PLGA or pSiO2 formulations. We conclude that this system may be useful in managing unwanted ocular proliferation when formulated with antiproliferation compounds such as DNR.

  11. Heuristic modeling of macromolecule release from PLGA microspheres

    PubMed Central

    Szlęk, Jakub; Pacławski, Adam; Lau, Raymond; Jachowicz, Renata; Mendyk, Aleksander

    2013-01-01

    Dissolution of protein macromolecules from poly(lactic-co-glycolic acid) (PLGA) particles is a complex process and still not fully understood. As such, there are difficulties in obtaining a predictive model that could be of fundamental significance in design, development, and optimization for medical applications and toxicity evaluation of PLGA-based multiparticulate dosage form. In the present study, two models with comparable goodness of fit were proposed for the prediction of the macromolecule dissolution profile from PLGA micro- and nanoparticles. In both cases, heuristic techniques, such as artificial neural networks (ANNs), feature selection, and genetic programming were employed. Feature selection provided by fscaret package and sensitivity analysis performed by ANNs reduced the original input vector from a total of 300 input variables to 21, 17, 16, and eleven; to achieve a better insight into generalization error, two cut-off points for every method was proposed. The best ANNs model results were obtained by monotone multi-layer perceptron neural network (MON-MLP) networks with a root-mean-square error (RMSE) of 15.4, and the input vector consisted of eleven inputs. The complicated classical equation derived from a database consisting of 17 inputs was able to yield a better generalization error (RMSE) of 14.3. The equation was characterized by four parameters, thus feasible (applicable) to standard nonlinear regression techniques. Heuristic modeling led to the ANN model describing macromolecules release profiles from PLGA microspheres with good predictive efficiency. Moreover genetic programming technique resulted in classical equation with comparable predictability to the ANN model. PMID:24348037

  12. Gamma Irradiation of Active Self-healing PLGA Microspheres for Efficient Aqueous Encapsulation of Vaccine Antigens

    PubMed Central

    Desai, Kashappa-Goud H.; Kadous, Samer; Schwendeman, Steven P.

    2013-01-01

    Purpose To investigate the effect of γ-irradiation of poly(lactic-co-glycolic acid) (PLGA)/Al(OH)3/0 or 5 wt% diethyl phthalate (DEP) microspheres for active self-healing encapsulation of vaccine antigens. Methods Microspheres were irradiated with 60Co at 2.5 and 1.8 MRad and 0.37 and 0.20 MRad/h. Encapsulation of tetanus toxoid (TT) was achieved by mixing Al(OH)3-PLGA microspheres with TT solution at 10-38°C. Electron paramagnetic resonance (EPR) spectroscopy was used to examine free radical formation. Glass transition temperature (Tg) and molecular weight of PLGA was measured by differential scanning calorimetry and gel permeation chromatography, respectively. Loading and release of TT were examined by modified Bradford, amino acid analysis, and ELISA assays. Results EPR spectroscopy results indicated absence of free radicals in PLGA microspheres after γ-irradiation. Antigen-sorbing capacity, encapsulation efficiency, and Tg of the polymer were also not adversely affected. When DEP-loaded microspheres were irradiated at 0.2 MRad/h, some PLGA pores healed during irradiation and PLGA healing during encapsulation was suppressed. The molecular weight of PLGA was slightly reduced when DEP-loaded microspheres were irradiated at the same dose rate. These trends were not observed at 0.37 MRad/h. Gamma irradiation slightly increased TT initial burst release. Apart from the slightly higher polymer molecular weight decline caused by higher irradiation dose in case of DEP-loaded microspheres, the small increase in total irradiation dose from 1.8 to 2.5 MRad had insignificant effect on the polymer and microspheres properties analyzed. Conclusion Gamma irradiation is a plausible approach to provide a terminally sterilized, self-healing encapsulation PLGA excipient for vaccine delivery. PMID:23515830

  13. In vitro characterization of hepatocyte growth factor release from PHBV/PLGA microsphere scaffold.

    PubMed

    Zhu, Xin Hao; Wang, Chi-Hwa; Tong, Yen Wah

    2009-05-01

    Polymer scaffolds which can support cells to grow as well as deliver growth factors to the cells simultaneously have great potential for the successful regeneration of failed tissues. As popularly used vehicles to deliver anti-cancer drugs and growth factors, microspheres also show many advantages as substrates to guide the growth of cells. Therefore, we aimed to examine the feasibility of using microspheres as ideal scaffolds for liver tissue engineering. To determine the capabilities of previously used microsphere scaffold to deliver growth factors simultaneously, this work investigated a long-term (about three months) release of bovine serum albumin (BSA) from microsphere scaffolds fabricated by using two different polymers, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV, 8% PHV), poly(lactide-co-glycolide) acid (PLGA, 5050) and a blend of PLGA and PHBV. BSA served as a model for hepatocyte growth factor (HGF) since both proteins have similar molecular weights and hydrophilicity. Furthermore, HGF was encapsulated into the PLGA/PHBV composite microsphere with a core-shell structure, and sustained delivery of HGF with maintained bioactivity was achieved for at least 40 days. The moderate degradation rate (about 55% loss of the initial mass) and well-preserved structure after three months of incubation indicated that the PLGA/PHBV composite microspheres would therefore be more suitable than the pure PHBV or PLGA microspheres as a scaffold for engineering liver tissue.

  14. Improving Protein Stability and Controlling Protein Release by Adding Poly (Cyclohexane-1, 4-Diyl Acetone Dimethylene Ketal) to PLGA Microspheres.

    PubMed

    Wang, Chenhui; Yu, Changhui; Yu, Kongtong; Teng, Lesheng; Liu, Jiaxin; Wang, Xuesong; Sun, Fengying; Li, Youxin

    2015-01-01

    The use of biodegradable polymers such as PLGA to encapsulate therapeutic proteins for their controlled release has received tremendous interest. However, an acidic environment caused by PLGA degradation productions leads to protein incomplete release and chemical degradation. The aim of this study was to develop novel PCADK/PLGA microspheres to improve protein stability and release behavior. Bovine serum albumin (BSA) incubated in PCADK and PLGA degradation products was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), size exclusion chromatography (SEC-HPLC), circular dichroism (CD) and fluorescence spectroscopy. Blended microspheres of PCADK/PLGA were prepared in different ratios and the release behaviors of the microspheres and the protein stability were then measured. The degradation properties of the microspheres and the pH inside the microspheres were systematically investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) to examine the mechanism of autocatalytic degradation and protein stability. BSA was more stable in the presence of PCADK monomers than it was in the presence of PLGA monomers, revealing that PCADK is highly compatible with this protein. PCADK/PLGA microspheres were successfully prepared, and 2/8 was determined to be the optimal ratio. Further, 43% of the BSA formed water-insoluble aggregates in the presence of PCADK/PLGA microspheres, compared with 57% for the PLGA microspheres, demonstrating that the BSA encapsulated in PCADK/PLGA blended microspheres was more stable than in PLGA microspheres. The PCADK/PLGA blended microspheres improved protein stability and release behavior, providing a promising protein drug delivery system.

  15. Sustained release of PTH(1-34) from PLGA microspheres suppresses osteoarthritis progression in rats.

    PubMed

    Eswaramoorthy, Rajalakshmanan; Chang, Chia-Chi; Wu, Shun-Cheng; Wang, Gwo-Jaw; Chang, Je-Ken; Ho, Mei-Ling

    2012-07-01

    We previously reported that PTH(1-34) inhibits the terminal differentiation of articular chondrocytes and, in turn, suppresses the progression of osteoarthritis (OA). However, this treatment requires an injection of PTH(1-34) once every 3 days over the treatment period. In this study, we studied the effect of sustained administration of PTH(1-34) in a papain-induced OA rat model. We developed an effective controlled-release system for prolonging the treatment duration of an intra-articular injection for OA treatment in rats. The effects of released PTH(1-34) from PLGA(65:35)-encapsulated PTH(1-34) microspheres (PTH/PLGA) on papain-induced OA in rat knees were studied. Microsphere morphology was observed in vitro by scanning electron microscopy, and microsphere size was determined with a particle size analyzer. The PTH(1-34) encapsulation efficiency and release profile, as well as the toxicity of PTH/PLGA, were examined. The bioactivity of released PTH(1-34) was tested by examining cAMP levels in MC3T3E1 cells. In vivo, we evaluated the changes of localized GAG, Col II, and Col X in the articular cartilage of rat knees. Our results demonstrated that the surface of the PLGA microspheres was smooth, and the size of the microspheres was in the range of 51-127 μm. PTH/PLGA microspheres sustainably released PTH(1-34) for 19 days with a concentration range of 0.01-100 nM that covered the expected concentration of 10nM at 37°C. The cAMP levels of MC3T3E1 cells were elevated in the response to released PTH(1-34) from PTH/PLGA microspheres, indicating that the released PTH(1-34) is bioactive. Most importantly, intra-articular treatment with either PTH(1-34) (0.1-100 nM) 3 days/injection or PTH/PLGA microspheres (15 days/injection) for 5 weeks revealed the similar effect on suppressing papain-induced OA changes (decreasing GAG and Col II and increasing Col X) in rat knee cartilage. The effect of PTH/PLGA microspheres on suppressing OA progression was similar to that of a

  16. cmRNA/lipoplex encapsulation in PLGA microspheres enables transfection via calcium phosphate cement (CPC)/PLGA composites.

    PubMed

    Utzinger, Maximilian; Jarzebinska, Anita; Haag, Nicolas; Schweizer, Martin; Winter, Gerhard; Dohmen, Christian; Rudolph, Carsten; Plank, Christian

    2017-03-10

    In this study lipoplexes containing chemically modified messenger RNA (cmRNA) were incorporated into poly (lactic-co-glycolic acid) (PLGA) microspheres via water-in-oil-in-water (W/O/W) double emulsion solvent evaporation technique. The nanoparticle encapsulation by microparticle formation was optimized to achieve lipoplex release and maximum transfection efficiency in surrounding cells. It was possible to adjust characteristic features in surface topology and size of the PLGA-microspheres by varying the extent of lipoplex loading into the polymer matrix. The partial release of lipids and mRNA out of the microparticle system, their accumulation in cells and the production of encoded protein were visualized via fluorescence microscopy. These bioactive microspheres, containing cmRNA bearing lipoplexes, were developed for the incorporation of a therapeutic component into injectable calcium phosphate cements (CPC). Due to the incorporation of PLGA/lipoplex microspheres as a degradable entity, the porosity of the cement phase could additionally be adjusted. This approach of complex nanoparticle incorporation into polymer/cement composites represents a promising example for combining transcript therapy with biomechanical engineering.

  17. Porous silicon oxide-PLGA composite microspheres for sustained ocular delivery of daunorubicin

    PubMed Central

    Nan, Kaihui; Ma, Feiyan; Hou, Huiyuan; Freeman, William R.; Sailor, Michael J.; Cheng, Lingyun

    2014-01-01

    A water-soluble anthracycline antibiotic drug (daunorubicin, DNR) was loaded into oxidized porous silicon (pSiO2) microparticles and then encapsulated with a layer of polymer (poly lactide-co-glycolide, PLGA) to investigate their synergistic effects in control of DNR release. Similarly fabricated PLGA-DNR microspheres without pSiO2, and pSiO2 microparticles without PLGA were used as control particles. The composite microparticles synthesized by a solid-in-oil-in-water (S/O/W) emulsion method have mean diameters of 52.33±16.37 μm for PLGA-pSiO2_21/40-DNR and the mean diameter of 49.31±8.87 μm for PLGA-pSiO2_6/20-DNR. The mean size, 26.00±8 μm, of PLGA-DNR was significantly smaller, compared with the other two (p<0.0001). Optical microscopy revealed that PLGA-pSiO2-DNR microsphere contained multiple pSiO2 particles. In vitro release experiments determined that control PLGA-DNR microspheres completely released DNR within 38 days and control pSiO2-DNR microparticles (with no PLGA coating) released DNR within 14 days, while the PLGA-pSiO2-DNR microspheres released DNR for 74 days. Temporal release profiles of DNR from PLGA-pSiO2 composite particles indicated that both PLGA and pSiO2 contribute to the sustained release of the payload. The PLGA-pSiO2 composite displayed a more constant rate of DNR release than the pSiO2 control formulation, and it displayed a significantly slower release of DNR than either the PLGA or pSiO2 formulations. We conclude that this system may be useful in managing unwanted ocular proliferation when formulated with anti-proliferation compounds such as DNR. PMID:24793657

  18. Enhanced oral bioavailability of salmeterol by loaded PLGA microspheres: preparation, in vitro, and in vivo evaluation.

    PubMed

    Zhang, Haiping; Xu, Jianfang

    2016-01-01

    The objective of the current study was to prepare microspheres of salmeterol (SM) using poly (lactide-co-glycolide) (PLGA) and assess its viability to enhance the oral bioavailability. Microspheres of SM were prepared by oil-in-water emulsion-solvent evaporation method. The formulations were characterized in encapsulation efficiency, particle size, zeta potential, and in vitro release. The prepared microspheres were found to be spherical in shape with smooth surface. The size of microspheres ranged from 14.7 to 16.5 µm. The polydispersity index (PDI) was 0.12 ± 0.05 and the zeta potential was -33.2 ± 1.4 mV. In vitro release profile, SM was graduated released from the microspheres as time lapsed, suggesting that SM was well entrapped in SM-loaded PLGA microspheres. The model that fitted best for SM released from the microspheres was Higuchi equation. In vivo study, SM-loaded PLGA microspheres are thought to have the potential to maintain SM concentration within target ranges for a long time, decreasing side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency.

  19. Pulsatile drug release from PLGA hollow microspheres by controlling the permeability of their walls with a magnetic field.

    PubMed

    Chiang, Wei-Lun; Ke, Cherng-Jyh; Liao, Zi-Xian; Chen, San-Yuan; Chen, Fu-Rong; Tsai, Chun-Ying; Xia, Younan; Sung, Hsing-Wen

    2012-12-07

    Pulsatile release: When a high-frequency magnetic field is applied, heat will be generated by coupling to the iron oxide nanoparticles encapsulated in the shells of PLGA hollow microspheres. As the temperature approaches the T(g) of PLGA, the polymer chains become more mobile, subsequently increasing the free volume of PLGA matrix and significantly enhancing the diffusion of drug molecules.

  20. Injectable PLGA microsphere/calcium phosphate cements: physical properties and degradation characteristics.

    PubMed

    Habraken, W J E M; Wolke, J G C; Mikos, A G; Jansen, J A

    2006-01-01

    Calcium phosphate (CaP) cements show an excellent biocompatibility and often have a high mechanical strength, but in general degrade relatively slow. To increase degradation rates, macropores can be introduced into the cement, e.g., by the inclusion of biodegradable microspheres into the cement. The aim of this research is to develop an injectable PLGA microsphere/CaP cement with sufficient setting/cohesive properties and good mechanical and physical properties. PLGA microspheres were prepared using a water-in-oil-in-water double-emulsion technique. The CaP-cement used was Calcibon, a commercially available hydroxyapatite-based cement. 10:90 and 20:80 dry wt% PLGA microsphere/CaP cylindrical scaffolds were prepared as well as microporous cement (reference material). Injectability, setting time, cohesive properties and porosity were determined. Also, a 12-week degradation study in PBS (37 degree C) was performed. Results showed that injectability decreased with an increase in PLGA microsphere content. Initial and final setting time of the PLGA/CaP samples was higher than the microporous sample. Porosity of the different formulations was 40.8% (microporous), 60.2% (10:90) and 69.3% (20:80). The degradation study showed distinct mass loss and a pH decrease of the surrounding medium starting from week 6 with the 10:90 and 20:80 formulations, indicating PLGA erosion. Compression strength of the PLGA microsphere/CaP samples decreased siginificantly in time, the microporous sample remained constant. After 12 weeks both PLGA/CaP samples showed a structure of spherical micropores and had a compressive strength of 12.2 MPa (10:90) and 4.3 MPa (20:80). Signs of cement degradation were also found with the 20:80 formulation. In conclusion, all physical parameters were well within workable ranges with both 10:90 and 20:80 PLGA microsphere/CaP cements. After 12 weeks the PLGA was totally degraded and a highly porous, but strong scaffold remained.

  1. Validation of a cage implant system for assessing in vivo performance of long-acting release microspheres.

    PubMed

    Doty, Amy C; Hirota, Keiji; Olsen, Karl F; Sakamoto, Naoya; Ackermann, Rose; Feng, Meihua R; Wang, Yan; Choi, Stephanie; Qu, Wen; Schwendeman, Anna; Schwendeman, Steven P

    2016-12-01

    Here we describe development of a silicone rubber/stainless steel mesh cage implant system, much like that used to assess biocompatibility of biomaterials [1], for easy removal of injectable polymer microspheres in vivo. The sterile cage has a type 316 stainless steel mesh size (38 μm) large enough for cell penetration and free fluid flow in vivo but small enough for microsphere retention, and a silicone rubber shell for injection of the microspheres. Two model drugs, the poorly soluble steroid, triamcinolone acetonide, and the highly water-soluble luteinizing hormone-releasing hormone (LHRH) peptide superagonist, leuprolide, were encapsulated in PLGA microspheres large enough (63-90 μm) to be restrained by the cage implant in vivo. The in vitro release from both formulations was followed by ultra-performance liquid chromatography (UPLC) with and without the cage in a standard release media, PBS pH 7.4 + 0.02% Tween 80 + 0.05% sodium azide, at 37 °C. Pharmacokinetics (PK) in rats was assessed after SC injection or SC in-cage implantation of microspheres with plasma analysis by LC-MS/MS or EIA. Tr-A and leuprolide in vitro release was largely unaffected after the initial burst irrespective of the cage or test tube incubation vessel and release was much slower than observed in vivo for both drugs. Moreover, Tr-A and leuprolide pharmacokinetics with and without the cage were highly similar during the 2-3 week release duration before a significant inflammatory response was caused by the cage implant. Hence, the PK-validated cage implant provides a simple means to recover and evaluate the microsphere drug carriers in vivo during a time window of at least a few weeks in order to characterize the polymer microsphere release and erosion behavior in vivo. This approach may facilitate development of mechanism-based in vitro/in vivo correlations and enable development of more accurate and useful in vitro release tests.

  2. Interaction between dimethyldioctadecylammonium bromide-modified PLGA microspheres and hyaluronic acid

    NASA Astrophysics Data System (ADS)

    Mulia, Kamarza; Devi, Krisanti, Elsa

    2017-02-01

    In application of intravitreal injection, an extended drug delivery system is desired so that the frequency of injection to treat diabetic retinopathy may be reduced. Poly(lactic-co-glycolic acid) polymer (PLGA) was used to encapsulate a model drug in the form of microspheres. The zeta potential of dimethyldioctadecylammonium bromide (DDAB)-modified PLGA microspheres in water was proportional to the DDAB concentration used in the preparation step, up to +57.8 mV. The scanning electron microscope pictures and the zeta potential data (SEM) confirmed that the surface of the PLGA has been modified by the cationic surfactant and that electrostatic interaction between the positively charged microspheres and the negatively charged vitreous were present.

  3. PLGA-Mesoporous Silicon Microspheres for the in Vivo Controlled Temporospatial Delivery of Proteins.

    PubMed

    Minardi, Silvia; Pandolfi, Laura; Taraballi, Francesca; De Rosa, Enrica; Yazdi, Iman K; Liu, Xeuwu; Ferrari, Mauro; Tasciotti, Ennio

    2015-08-05

    In regenerative medicine, the temporospatially controlled delivery of growth factors (GFs) is crucial to trigger the desired healing mechanisms in the target tissues. The uncontrolled release of GFs has been demonstrated to cause severe side effects in the surrounding tissues. The aim of this study was to optimize a translational approach for the fine temporal and spatial control over the release of proteins, in vivo. Hence, we proposed a newly developed multiscale composite microsphere based on a core consisting of the nanostructured silicon multistage vector (MSV) and a poly(dl-lactide-co-glycolide) acid (PLGA) outer shell. Both of the two components of the resulting composite microspheres (PLGA-MSV) can be independently tailored to achieve multiple release kinetics contributing to the control of the release profile of a reporter protein in vitro. The influence of MSV shape (hemispherical or discoidal) and size (1, 3, or 7 μm) on PLGA-MSV's morphology and size distribution was investigated. Second, the copolymer ratio of the PLGA used to fabricate the outer shell of PLGA-MSV was varied. The composites were fully characterized by optical microscopy, scanning electron microscopy, ζ potential, Fourier transform infrared spectroscopy, and thermogravimetric analysis-differential scanning calorimetry, and their release kinetics over 30 days. PLGA-MSV's biocompatibility was assessed in vitro with J774 macrophages. Finally, the formulation of PLGA-MSV was selected, which concurrently provided the most consistent microsphere size and allowed for a zero-order release kinetic. The selected PLGA-MSVs were injected in a subcutaneous model in mice, and the in vivo release of the reporter protein was followed over 2 weeks by intravital microscopy, to assess if the zero-order release was preserved. PLGA-MSV was able to retain the payload over 2 weeks, avoiding the initial burst release typical of most drug delivery systems. Finally, histological evaluation assessed the

  4. Injectable long-acting systems for Radix Ophiopogonis polysaccharide based on mono-PEGylation and in situ formation of a PLGA depot

    PubMed Central

    Shi, XiaoLi; Lin, Xiao; Zheng, XiangWei; Feng, Yi; Shen, Lan

    2014-01-01

    Background Radix Ophiopogonis polysaccharide (ROP), a highly hydrophilic macromolecule, has a unique anti-ischemic action in the myocardium. One of the main problems with its use is its relatively short half-life in vivo. To solve this problem, injectable long-acting drug delivery systems, which combine mono-PEGylation (PEG, polyethylene glycol) with the in situ formation of poly(d,l-lactide-co-glycolide) copolymer (PLGA) depots, were tested in this study. Methods Through a moderate coupling reaction between 20 kDa amino-terminated methoxy-PEG and excessive ROP with activated hydroxyls, a long-circulating and bioactive mono-PEGylated ROP was prepared and characterized. A reasonable and applicable range of PLGA formulations loaded with the mono-PEGylated ROP were prepared, characterized, and evaluated in vivo. Results Relative to ROP, the half-life of which was only 0.5 hours, the conjugate alone, following subcutaneous administration, showed markedly prolonged retention in the systemic circulation, with a mean residence time in vivo of approximately 2.76 days. In combination with in situ-forming PLGA depots, the residence time of the conjugate in vivo was prolonged further. In particular, a long-lasting and steady plasma exposure for nearly a month was achieved by the formulation comprising 40% 30 kDa PLGA in N-methyl-2-pyrrolidone. Conclusion Long-lasting and steady drug exposure could be achieved using mono-PEGylation in combination with in situ formation of PLGA depots. Such a combination with ROP would be promising for long-term prophylaxis and/or treatment of myocardial ischemia. For high-dose and highly hydrophilic macromolecular drugs like ROP, more than one preparation technology might be needed to achieve week-long or month-long delivery per dosing. PMID:25489243

  5. PHBV microspheres--PLGA matrix composite scaffold for bone tissue engineering.

    PubMed

    Huang, Wei; Shi, Xuetao; Ren, Li; Du, Chang; Wang, Yingjun

    2010-05-01

    Polymer scaffolds, particularly in the form of microspheres, have been employed to support cells growth and deliver drugs or growth factors in tissue engineering. In this study, we have established a scaffold by embedding poly (beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV) microspheres into poly (L-lactic-co-glycolic acid) (PLGA) matrix, according to their different solubility in acetone, with the aim of repairing bone defects. PLGA/PHBV scaffolds had good pore parameters, for example, the porosity of PLGA/30% PHBV scaffold can reach to 81.273 +/- 2.192%. Besides, the pore size distribution of the model was evaluated and the results revealed that the pore size mainly distributed between 50 mum and 200 mum. With increasing the amount of PHBV microspheres, the compressive strength of the PLGA/PHBV scaffold enhanced. The morphology of the hybrid scaffold was rougher than that of pure PLGA scaffold, which had no significant effect on the cell behavior. The in vitro evaluation suggested that the model is suitable as a scaffold for engineering bone tissue, and has the potential for further applications in drug delivery system.

  6. PLGA-Listeriolysin O microspheres: Opening the gate for cytosolic delivery of cancer antigens.

    PubMed

    Gilert, Ariel; Baruch, Limor; Bronshtein, Tomer; Machluf, Marcelle

    2016-04-01

    Strategies for cancer protein vaccination largely aim to activate the cellular arm of the immune system against cancer cells. This approach, however, is limited since protein vaccines mostly activate the system's humoral arm instead. One way to overcome this problem is to enhance the cross-presentation of such proteins by antigen-presenting cells, which may consequently lead to intense cellular response. Here we examined the ability of listeriolysin O (LLO) incorporated into poly-lactic-co-glycolic acid (PLGA) microspheres to modify the cytosolic delivery of low molecular weight peptides and enhance their cross-presentation. PLGA microspheres were produced in a size suitable for uptake by phagocytic cells. The peptide encapsulation and release kinetics were improved by adding NaCl to the preparation. PLGA microspheres loaded with the antigenic peptide and incorporated with LLO were readily up-taken by phagocytic cells, which exhibited an increase in the expression of peptide-MHC-CI complexes on the cell surface. Furthermore, this system enhanced the activation of a specific T hybridoma cell line, thus simulating cytotoxic T cells. These results establish, for the first time, a proof of concept for the use of PLGA microspheres incorporated with a pore-forming agent and the antigen peptide of choice as a unique cancer protein vaccination delivery platform.

  7. Sophoridine-loaded PLGA microspheres for lung targeting: preparation, in vitro, and in vivo evaluation.

    PubMed

    Wang, Wenping; Cai, Yaqin; Zhang, Guangxing; Liu, Yanhua; Sui, Hong; Park, Kinam; Wang, Hong

    2016-11-01

    Lung-targeting sophoridine-loaded poly(lactide-co-glycolide) (PLGA) microspheres were constructed by a simple oil-in-oil emulsion-solvent evaporation method. The obtained microspheres were systematically studied on their morphology, size distribution, drug loading, encapsulation efficiency, in vitro release profile, and biodistribution in rats. The drug-loaded microparticles showed as tiny spheres under SEM and had an average size of 17 μm with 90% of the microspheres ranging from 12 to 24 μm. The drug loading and encapsulation efficiency were 65% and 6.5%, respectively. The in vitro drug release behavior of microspheres exhibited an initial burst of 16.6% at 4 h and a sustained-release period of 14 days. Drug concentration in lung tissue of rats was 220.10 μg/g for microspheres and 6.77 μg/g for solution after intraveneous injection for 30 min, respectively. And the microsphere formulation showed a significantly higher drug level in lung tissue than in other major organs and blood samples for 12 days. These results demonstrated that the obtained PLGA microspheres could potentially improve the treatment efficacy of sophoridine against lung cancer.

  8. In vitro and in vivo performance of dexamethasone loaded PLGA microspheres prepared using polymer blends.

    PubMed

    Gu, Bing; Wang, Yan; Burgess, Diane J

    2015-12-30

    The foreign body reaction is the major cause of the dysfunction and relatively short lifetime associated with implanted glucose biosensors. An effective strategy to maintain sensor functionality is to apply biocompatible coatings that elute drug to counter the negative tissue reactions. This has been achieved using dexamethasone releasing poly(lactic-co-glycolic acid) (PLGA) microspheres embedded in a polyvinyl alcohol (PVA) hydrogel coating. Accordingly, the biosensor lifetime relies on the duration and dose of drug release from the coating. To achieve long-term drug release mixed populations of microspheres have been used. In the current study, microspheres were prepared by blending low (25KDa) and high (113KDa) molecular weight PLGA at different mass ratios to overcome problems associated with mixing multiple populations of microspheres. "Real-time" in vitro studies demonstrated dexamethasone release for approximately 5 months. An accelerated method with discriminatory ability was developed to shorten drug release to less than 2 weeks. An in vivo pharmacodynamics study demonstrated efficacy against the foreign body reaction for 4.5 months. Such composite coatings composed of PLGA microspheres prepared using polymer blends could potentially be used to ensure long-term performance of glucose sensors.

  9. Mechanisms of in vivo release of triamcinolone acetonide from PLGA microspheres.

    PubMed

    Doty, Amy C; Weinstein, David G; Hirota, Keiji; Olsen, Karl F; Ackermann, Rose; Wang, Yan; Choi, Stephanie; Schwendeman, Steven P

    2017-03-22

    Little is known about the underlying effects controlling in vitro-in vivo correlations (IVIVCs) for biodegradable controlled release microspheres. Most reports of IVIVCs that exist are empirical in nature, typically based on a mathematical relationship between in vitro and in vivo drug release, with the latter often estimated by deconvolution of pharmacokinetic data. In order to improve the ability of in vitro release tests to predict microsphere behavior in vivo and develop more meaningful IVIVCs, the in vivo release mechanisms need to be characterized. Here, two poly(lactic-co-glycolic acid) (PLGA) microsphere formulations encapsulating the model steroid triamcinolone acetonide (Tr-A) were implanted subcutaneously in rats by using a validated cage model, allowing for free fluid and cellular exchange and microsphere retrieval during release. Release kinetics, as well as mechanistic indicators of release such as hydrolysis and mass loss, was measured by direct analysis of the recovered microspheres. Release of Tr-A from both formulations was greatly accelerated in vivo compared to in vitro using agitated phosphate buffered saline +0.02% Tween 80 pH7.4, including rate of PLGA hydrolysis, mass loss and water uptake. Both microsphere formulations exhibited erosion-controlled release in vitro, indicated by similar polymer mass loss kinetics, but only one of the formulations (low molecular weight, free acid terminated) exhibited the same mechanism in vivo. The in vivo release of Tr-A from microspheres made of a higher molecular weight, ester end-capped PLGA displayed an osmotically induced/pore diffusion mechanism based on confocal micrographs of percolating pores in the polymer, not previously observed in vitro. This research indicates the need to fully understand the in vivo environment and how it causes drug release from biodegradable microspheres. This understanding can then be applied to develop in vitro release tests which better mimic this environment and cause

  10. Studies on the preparation, characterization and pharmacological evaluation of tolterodine PLGA microspheres.

    PubMed

    Sun, Fengying; Sui, Cheng; Teng, Lesheng; Liu, Ximing; Teng, Lirong; Meng, Qingfan; Li, Youxin

    2010-09-15

    In this study, poly(d,l-lactide-co-glycolide) (PLGA) microspheres of tolterodine depot formulation were prepared using oil in water (o/w) method to investigate their potential pharmacokinetic and pharmacodynamic advantages over tolterodine l-tartrate tablets. Morphological studies of the microspheres showed a spherical shape and smooth surface with mean size of 50.69-83.01 microm, and the encapsulation efficiency was improved from 62.55 to 79.10% when the polymer concentration increased from 180 to 230 mg/ml. The addition of stearic or palmitic acids could significantly raise the drug entrapment efficiency but only slightly affected the in vitro release. A low initial burst followed by a proximately constant release of tolterodine was noticed in the in vitro release profiles. The in vivo study was carried out by intramuscular (i.m.) administration of tolterodine-loaded microspheres on beagle dogs, and a sustained release of drug from the PLGA microspheres was achieved until the 18th day with a low initial burst. Since the absence of hepatic first pass metabolism, only a single active compound-tolterodine was detected in the plasma. This avoided the coexistence of two active compounds in plasma in the case of oral administration of tolterodine, which may lead to a difficulty in dose control due to the different metabolic capacity of patients. In the pharmacodynamic study, the influence of tolterodine PLGA microspheres on the inhibition of carbachol-induced rat urinary bladder contraction was more significant than that of tolterodine l-tartrate tablets. There were invisible changes in rat bladder slices between tolterodine-loaded PLGA microspheres group and tolterodine l-tartrate tablets group. These results indicate that the continuous inhibition of muscarinic receptor may offer an alternative therapy of urge incontinence.

  11. Stabilization of Human Immunoglobulin G Encapsulated within Biodegradable Poly (Cyclohexane-1, 4-diyl Acetone Dimethylene Ketal) (PCADK)/ Poly (Lactic-co-Glycolic Acid) (PLGA) Blend Microspheres.

    PubMed

    Wang, Chenhui; Yu, Changhui; Liu, Jiaxin; Sun, Fengying; Teng, Lesheng; Li, Youxin

    2015-01-01

    The aim of this study was to prepare PCADK/PLGA-blend microspheres for improving the stability of human immunoglobulin G (IgG). The short half-life of antibodies limit their development as therapeutic agents, thus PLGA microspheres were prepared to sustained release antibodies and prolong their half-life. However, the acidic intra-microsphere environment causes the loss of antibody stability and activity. In this study, the effect of PCADK or PLGA degradation products on IgG was investigated by size exclusion chromatography (SEC-HPLC), circular dichroism (CD), fluorescence spectroscopy and antigenicity detection. The degradation products of PCADK exerted a larger influence on IgG than that of PLGA. Then PCADK/PLGA microspheres were prepared by the emulsionsolvent evaporation method and systematically characterized and 20% PCADK were selected as the optimal proportion. In addition, the release profile of microspheres and the stability of the released IgG were investigated. The stability of the IgG released from the PCADK/PLGA microspheres was better than that of IgG released from the PLGA microspheres. Confocal laser scanning microscopy (CLSM) was used to determine the pH inside the microspheres. The IgG-loaded PCADK/PLGA microspheres have important advantages over the PLGA microspheres in terms of IgG stability and could be a good carrier to deliver antibodies for the treatment of disease.

  12. Pharmacokinetics and distributions of bevacizumab by intravitreal injection of bevacizumab-PLGA microspheres in rabbits

    PubMed Central

    Ye, Zhuo; Ji, Yan-Li; Ma, Xiang; Wen, Jian-Guo; Wei, Wei; Huang, Shu-Man

    2015-01-01

    AIM To investigate the pharmacokinetics and distributions of bevacizumab by intravitreal injection of prepared bevacizumab-poly (L-lactic-co-glycolic acid) (PLGA) microspheres in rabbits, to provide evidence for clinical application of this kind of bevacizumab sustained release dosage form. METHODS Bevacizumab was encapsulated into PLGA microsphere via the solid-in-oil-in-hydrophilic oil (S/O/hO) method. Fifteen healthy New Zealand albino-rabbits were used in experiments. The eyes of each rabbit received an intravitreal injection. The left eyes were injected with prepared bevacizumab-PLGA microspheres and the right eyes were injected with bevacizumab solution. After intravitreal injection, rabbits were randomly selected at days 3, 7, 14, 28 and 42 respectively, three animals each day. Then we used immunofluorescence staining to observe the distribution and duration of bevacizumab in rabbit eye tissues, and used the sandwich ELISA to quantify the concentration of free bevacizumab from the rabbit aqueous humor and vitreous after intravitreal injection. RESULTS The results show that the concentration of bevacizumab in vitreous and aqueous humor after administration of PLGA formulation was higher than that of bevacizumab solution. The T1/2 of intravitreal injection of bevacizumab-PLGA microspheres is 9.6d in vitreous and 10.2d in aqueous humor, and the T1/2 of intravitreal injection of soluble bevacizumab is 3.91d in vitreous and 4.1d in aqueous humor. There were statistical significant difference for comparison the results of the bevacizumab in vitreous and aqueous humor between the left and right eyes (P<0.05). The AUC0-t of the sustained release dosage form was 1-fold higher than that of the soluble form. The relative bioavailability was raised significantly. The immunofluorescence staining of PLGA-encapsulated bevacizumab (b-PLGA) in rabbit eye tissues was still observed up to 42d. It was longer than that of the soluble form. CONCLUSION The result of this study

  13. Sequential delivery of chlorhexidine acetate and bFGF from PLGA-glycol chitosan core-shell microspheres.

    PubMed

    Chen, Ming-Mao; Cao, Huan; Liu, Yuan-Yuan; Liu, Yan; Song, Fei-Fei; Chen, Jing-Di; Zhang, Qi-Qing; Yang, Wen-Zhi

    2017-03-01

    Wound treatment should meet the challenge both of preventing infection and promoting wound healing. To design a sequential delivery system for wound healing, PLGA-glycol chitosan (GC) core-shell microspheres containing chlorhexidine acetate (CHA) at the GC shell and bFGF in the core of PLGA microspheres were fabricated using emulsion-solvent evaporation method. SEM showed that the microspheres were all spherical in shape with a smooth surface. The average size of PLGA-GC microspheres increased due to the GC coating on the surface. The results of release profiles and fluorescence images indicated that PLGA-GC microspheres had an ability to deliver drugs in sequence. The CHA was rapidly released, whereas the proteins presented a sustained release. The release behavior could be modulated by changing the GC amount. Antibacterial assay and cell proliferation tests suggested that the released CHA and bFGF retained their antimicrobial activity and bioactivity during preparation. The microspheres exhibited non-cytotoxicity against 3T3 cells and had a good biocompatibility. These results demonstrated that PLGA-GC core-shell microspheres could be a promising controlled release system of delivering drugs and proteins in sequence for wound healing.

  14. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair.

    PubMed

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei; Tao, Xiaojun; Zhang, Zhihua; Sun, Xiaomin; Zhang, Qiqing

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration.

  15. Biological activity of rhBMP-2 released from PLGA microspheres.

    PubMed

    Oldham, J B; Lu, L; Zhu, X; Porter, B D; Hefferan, T E; Larson, D R; Currier, B L; Mikos, A G; Yaszemski, M J

    2000-06-01

    Human recombinant bone morphogenetic protein-2 (rhBMP-2) has been proven effective in stimulating the regeneration of bone in both skeletal and extraskeletal locations. Through encapsulation within, and release from, biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) microspheres, a proven vehicle for sustained delivery of various proteins, the local concentrations of rhBMP-2 could be maintained at optimal levels to stimulate bone regeneration and remodeling at the site of healing in diverse clinical settings. Thus the purpose of this work was to investigate the encapsulation of rhBMP-2 in PLGA microspheres and its biologic activity upon release. Using in vitro tests in simulated body fluids, the effect of rhBMP-2 released from PLGA microspheres upon osteoblast cell cultures was found to be statistically similar to the effect produced by positive controls consisting of nonencapsulated aqueous rhBMP-2 in simulated body fluids. This clarifies an important step in skeletal tissue engineering strategies aimed at the use of encapsulated rhBMP-2 to stimulate bone regeneration and remodeling.

  16. Room-temperature attachment of PLGA microspheres to titanium surfaces for implant-based drug release

    NASA Astrophysics Data System (ADS)

    Xiao, Dongqin; Liu, Qing; Wang, Dongwei; Xie, Tao; Guo, Tailin; Duan, Ke; Weng, Jie

    2014-08-01

    Drug release from implant surfaces is an effective approach to impart biological activities, (e.g., antimicrobial and osteogenic properties) to bone implants. Coatings of polylactide-based polymer are a candidate for this purpose, but a continuous (fully covering) coating may be non-optimal for implant-bone fixation. This study reports a simple room-temperature method for attaching poly (lactide-co-glycolide) (PLGA) microspheres to titanium (Ti) surfaces. Microspheres were prepared with polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) as the emulsifier. Microspheres were attached to Ti discs by pipetting as a suspension onto the surfaces followed by vacuum drying. After immersion in shaking water bath for 14 d, a substantial proportion of the microspheres remained attached to the discs. In contrast, if the vacuum-drying procedure was omitted, only a small fraction of the microspheres remained attached to the discs after immersion for only 5 min. Microspheres containing triclosan (a broad-spectrum antibiotic) were attached by porous-surfaced Ti discs. In vitro experiments showed that the microsphere-carrying discs were able to kill Staphylococcus aureus and Escherichia Coli, and support the adhesion and growth of primary rat osteoblasts. This simple method may offer a flexible technique for bone implant-based drug release.

  17. Biocompatibility and osteogenesis of calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres for bone tissue engineering.

    PubMed

    Zhang, Hao-Xuan; Xiao, Gui-Yong; Wang, Xia; Dong, Zhao-Gang; Ma, Zhi-Yong; Li, Lei; Li, Yu-Hua; Pan, Xin; Nie, Lin

    2015-10-01

    By utilizing a modified solid/oil/water (s/o/w) emulsion solvent evaporation technique, calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres (SIM-PLGA-CPC) were prepared in this study. We characterized the morphology, encapsulation efficiency and in vitro drug release of SIM-loaded PLGA microspheres as well as the macrostructure, pore size, porosity and mechanical strength of the scaffolds. Rabbit bone mesenchymal stem cells (BMSCs) were seeded onto SIM-PLGA-CPC scaffolds, and the proliferation, morphology, cell cycle and differentiation of BMSCs were investigated using the cell counting kit-8 (CCK-8) assay, scanning electron microscopy (SEM), flow cytometry, alkaline phosphatase (ALP) activity and alizarin red S staining, respectively. The results revealed that SIM-PLGA-CPC scaffolds were biocompatible and osteogenic in vitro. To determine the in vivo biocompatibility and osteogenesis of the scaffolds, both pure PLGA-CPC scaffolds and SIM-PLGA-CPC scaffolds were implanted in rabbit femoral condyles and microradiographically and histologically investigated. SIM-PLGA-CPC scaffolds exhibited good biocompatibility and could improve the efficiency of new bone formation. All these results suggested that the SIM-PLGA-CPC scaffolds fulfilled the basic requirements of bone tissue engineering scaffold and possessed application potentials in orthopedic surgery.

  18. Microencapsulation of inorganic nanocrystals into PLGA microsphere vaccines enables their intracellular localization in dendritic cells by electron and fluorescence microscopy.

    PubMed

    Schliehe, Christopher; Schliehe, Constanze; Thiry, Marc; Tromsdorf, Ulrich I; Hentschel, Joachim; Weller, Horst; Groettrup, Marcus

    2011-05-10

    Biodegradable poly-(D,L-lactide-co-glycolide) microspheres (PLGA-MS) are approved as a drug delivery system in humans and represent a promising antigen delivery device for immunotherapy against cancer. Immune responses following PLGA-MS vaccination require cross-presentation of encapsulated antigen by professional antigen presenting cells (APCs). While the potential of PLGA-MS as vaccine formulations is well established, the intracellular pathway of cross-presentation following phagocytosis of PLGA-MS is still under debate. A part of the controversy stems from the difficulty in unambiguously identifying PLGA-MS within cells. Here we show a novel strategy for the efficient encapsulation of inorganic nanocrystals (NCs) into PLGA-MS as a tool to study their intracellular localization. We microencapsulated NCs as an electron dense marker to study the intracellular localization of PLGA-MS by transmission electron microscopy (TEM) and as fluorescent labels for confocal laser scanning microscopy. Using this method, we found PLGA-MS to be rapidly taken up by dendritic cells and macrophages. Co-localization with the lysosomal marker LAMP1 showed a lysosomal storage of PLGA-MS for over two days after uptake, long after the initiation of cross-presentation had occurred. Our data argue against an escape of PLGA-MS from the endosome as has previously been suggested as a mechanism to facilitate cross-presentation of PLGA-MS encapsulated antigen.

  19. Injectable and porous PLGA microspheres that form highly porous scaffolds at body temperature.

    PubMed

    Qutachi, Omar; Vetsch, Jolanda R; Gill, Daniel; Cox, Helen; Scurr, David J; Hofmann, Sandra; Müller, Ralph; Quirk, Robin A; Shakesheff, Kevin M; Rahman, Cheryl V

    2014-12-01

    Injectable scaffolds are of interest in the field of regenerative medicine because of their minimally invasive mode of delivery. For tissue repair applications, it is essential that such scaffolds have the mechanical properties, porosity and pore diameter to support the formation of new tissue. In the current study, porous poly(dl-lactic acid-co-glycolic acid) (PLGA) microspheres were fabricated with an average size of 84±24μm for use as injectable cell carriers. Treatment with ethanolic sodium hydroxide for 2min was observed to increase surface porosity without causing the microsphere structure to disintegrate. This surface treatment also enabled the microspheres to fuse together at 37°C to form scaffold structures. The average compressive strength of the scaffolds after 24h at 37°C was 0.9±0.1MPa, and the average Young's modulus was 9.4±1.2MPa. Scaffold porosity levels were 81.6% on average, with a mean pore diameter of 54±38μm. This study demonstrates a method for fabricating porous PLGA microspheres that form solid porous scaffolds at body temperature, creating an injectable system capable of supporting NIH-3T3 cell attachment and proliferation in vitro.

  20. Fabrication and evaluation of a sustained-release chitosan-based scaffold embedded with PLGA microspheres.

    PubMed

    Song, Kedong; Liu, Yingchao; Macedo, Hugo M; Jiang, Lili; Li, Chao; Mei, Guanyu; Liu, Tianqing

    2013-04-01

    Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27-55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 °C in an aqueous environment of 1% chitosan-based scaffolds were (92.99±2.51) %, (89.66±0.66) % and (73.77±3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24±0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44±1.81)×10(-2) mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique

  1. Release mechanisms of tacrolimus-loaded PLGA and PLA microspheres and immunosuppressive effects of the microspheres in a rat heart transplantation model.

    PubMed

    Kojima, Ryo; Yoshida, Takatsune; Tasaki, Hiroaki; Umejima, Hiroyuki; Maeda, Masashi; Higashi, Yasuyuki; Watanabe, Shunsuke; Oku, Naoto

    2015-08-15

    The objective of this study was to elucidate the release and absorption mechanisms of tacrolimus loaded into microspheres composed of poly(lactic-co-glycolic acid) (PLGA) and/or polylactic acid (PLA). Tacrolimus-loaded microspheres were prepared by the o/w emulsion solvent evaporation method. The entrapment efficiency correlated with the molecular weight of PLGA, and the glass transition temperature of PLGA microspheres was not decreased by the addition of tacrolimus. These results indicate that intermolecular interaction between tacrolimus and the polymer would affect the entrapment of tacrolimus in the microspheres. Tacrolimus was released with weight loss of the microspheres, and the dominant release mechanism of tacrolimus was considered to be erosion of the polymer rather than diffusion of the drug. The whole-blood concentration of tacrolimus in rats was maintained for at least 2 weeks after a single subcutaneous administration of the microspheres. The pharmacokinetic profile of tacrolimus following subcutaneous administration was similar to that following intramuscular administration, suggesting that the release and dissolution of tacrolimus, rather than the absorption of the dissolved tacrolimus, were rate-limiting steps. Graft-survival time in a heart transplantation rat model was prolonged by the administration of tacrolimus-loaded microspheres. The microsphere formulation of tacrolimus would be expected to precisely control the blood concentration while maintaining the immunosuppressive effect of the drug.

  2. Electrospray synthesis and properties of hierarchically structured PLGA TIPS microspheres for use as controlled release technologies.

    PubMed

    Malik, Salman A; Ng, Wing H; Bowen, James; Tang, Justin; Gomez, Alessandro; Kenyon, Anthony J; Day, Richard M

    2016-04-01

    Microsphere-based controlled release technologies have been utilized for the long-term delivery of proteins, peptides and antibiotics, although their synthesis poses substantial challenges owing to formulation complexities, lack of scalability, and cost. To address these shortcomings, we used the electrospray process as a reproducible, synthesis technique to manufacture highly porous (>94%) microspheres while maintaining control over particle structure and size. Here we report a successful formulation recipe used to generate spherical poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray (ES) coupled with a novel thermally induced phase separation (TIPS) process with a tailored Liquid Nitrogen (LN2) collection scheme. We show how size, shape and porosity of resulting microspheres can be controlled by judiciously varying electrospray processing parameters and we demonstrate examples in which the particle size (and porosity) affect release kinetics. The effect of electrospray treatment on the particles and their physicochemical properties are characterized by scanning electron microscopy, confocal Raman microscopy, thermogravimetric analysis and mercury intrusion porosimetry. The microspheres manufactured here have successfully demonstrated long-term delivery (i.e. 1week) of an active agent, enabling sustained release of a dye with minimal physical degradation and have verified the potential of scalable electrospray technologies for an innovative TIPS-based microsphere production protocol.

  3. Computational Intelligence Modeling of the Macromolecules Release from PLGA Microspheres-Focus on Feature Selection.

    PubMed

    Zawbaa, Hossam M; Szlȩk, Jakub; Grosan, Crina; Jachowicz, Renata; Mendyk, Aleksander

    2016-01-01

    Poly-lactide-co-glycolide (PLGA) is a copolymer of lactic and glycolic acid. Drug release from PLGA microspheres depends not only on polymer properties but also on drug type, particle size, morphology of microspheres, release conditions, etc. Selecting a subset of relevant properties for PLGA is a challenging machine learning task as there are over three hundred features to consider. In this work, we formulate the selection of critical attributes for PLGA as a multiobjective optimization problem with the aim of minimizing the error of predicting the dissolution profile while reducing the number of attributes selected. Four bio-inspired optimization algorithms: antlion optimization, binary version of antlion optimization, grey wolf optimization, and social spider optimization are used to select the optimal feature set for predicting the dissolution profile of PLGA. Besides these, LASSO algorithm is also used for comparisons. Selection of crucial variables is performed under the assumption that both predictability and model simplicity are of equal importance to the final result. During the feature selection process, a set of input variables is employed to find minimum generalization error across different predictive models and their settings/architectures. The methodology is evaluated using predictive modeling for which various tools are chosen, such as Cubist, random forests, artificial neural networks (monotonic MLP, deep learning MLP), multivariate adaptive regression splines, classification and regression tree, and hybrid systems of fuzzy logic and evolutionary computations (fugeR). The experimental results are compared with the results reported by Szlȩk. We obtain a normalized root mean square error (NRMSE) of 15.97% versus 15.4%, and the number of selected input features is smaller, nine versus eleven.

  4. Localized and sustained delivery of erythropoietin from PLGA microspheres promotes functional recovery and nerve regeneration in peripheral nerve injury.

    PubMed

    Zhang, Wei; Gao, Yuan; Zhou, Yan; Liu, Jianheng; Zhang, Licheng; Long, Anhua; Zhang, Lihai; Tang, Peifu

    2015-01-01

    Erythropoietin (EPO) has been demonstrated to exert neuroprotective effects on peripheral nerve injury recovery. Though daily intraperitoneal injection of EPO during a long period of time was effective, it was a tedious procedure. In addition, only limited amount of EPO could reach the injury sites by general administration, and free EPO is easily degraded in vivo. In this study, we encapsulated EPO in poly(lactide-co-glycolide) (PLGA) microspheres. Both in vitro and in vivo release assays showed that the EPO-PLGA microspheres allowed sustained release of EPO within a period of two weeks. After administration of such EPO-PLGA microspheres, the peripheral nerve injured rats had significantly better recovery compared with those which received daily intraperitoneal injection of EPO, empty PLGA microspheres, or saline treatments. This was supported by the functional, electrophysiological, and histological evaluations of the recovery done at week 8 postoperatively. We conclude that sustained delivery of EPO could be achieved by using EPO-PLGA microspheres, and such delivery method could further enhance the recovery function of EPO in nerve injury recovery.

  5. Surface-assembled poly(I:C) on PEGylated PLGA microspheres as vaccine adjuvant: APC activation and bystander cell stimulation.

    PubMed

    Hafner, Annina M; Corthésy, Blaise; Textor, Marcus; Merkle, Hans P

    2016-11-30

    Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres are potential vehicles to deliver antigens for vaccination. Because they lack the full capacity to activate professional antigen presenting cells (APCs), combination with an immunostimulatory adjuvant may be considered. A candidate is the synthetic TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), which drives cell-mediated immunity. However, poly(I:C) has also been linked to the pathogenesis of autoimmunity, as affected by widespread stimulation of non-hematopoietic bystander cells. To address this aspect, we propose to minimize the poly(I:C) dose as well as to control the stimulation of non-immune bystander cells by poly(I:C). To facilitate the maturation of APCs with minimal poly(I:C) doses, we surface-assembled poly(I:C) onto PLGA microspheres. The microspheres' surface was further modified by poly(ethylene glycol) (PEG) coronas with varying PEG-densities. PLGA microspheres loaded with tetanus toxoid (tt) as model antigen were manufactured by microextrusion-based solvent extraction. The negatively charged PLGA(tt) microspheres were coated with polycationic poly(l-lysine) (PLL) polymers, either PLL itself or PEG-grafted PLL (PLL-g-PEG) with varying grafting ratios (g=2.2 and g=10.1). Stable surface assembly of poly(I:C) was achieved by subsequent incubation of polymer-coated PLGA microspheres with aqueous poly(I:C) solutions. We evaluated the immunostimulatory potential of such PLGA(tt) microsphere formulations on monocyte-derived dendritic cells (MoDCs) as well as human foreskin fibroblasts (HFFs) as model for non-hematopoietic bystander cells. Formulations with surface-assembled poly(I:C) readily activated MoDCs with respect to the expression of maturation-related surface markers, proinflammatory cytokine secretion and directed migration. When surface-assembled, poly(I:C) enhanced its immunostimulatory activity by more than one order of magnitude as compared to free poly

  6. The Effect of Temozolomide/Poly(lactide-co-glycolide) (PLGA)/Nano-Hydroxyapatite Microspheres on Glioma U87 Cells Behavior

    PubMed Central

    Zhang, Dongyong; Tian, Ang; Xue, Xiangxin; Wang, Mei; Qiu, Bo; Wu, Anhua

    2012-01-01

    In this study, we investigated the effects of temozolomide (TMZ)/Poly (lactide-co-glycolide)(PLGA)/nano-hydroxyapatite microspheres on the behavior of U87 glioma cells. The microspheres were fabricated by the “Solid/Water/Oil” method, and they were characterized by using X-Ray diffraction, scanning electron microscopy and differential scanning calorimetry. The proliferation, apoptosis and invasion of glioma cells were evaluated by MTT, flow cytometry assay and Transwell assay. The presence of the key invasive gene, αVβ3 integrin, was detected by the RT-PCR and Western blot method. It was found that the temozolomide/PLGA/nano-hydroxyapatite microspheres have a significantly diminished initial burst of drug release, compared to the TMZ laden PLGA microspheres. Our results suggest they can significantly inhibit the proliferation and invasion of glioma cells, and induce their apoptosis. Additionally, αVβ3 integrin was also reduced by the microspheres. These data suggest that by inhibiting the biological behavior of glioma cells in vitro, the newly designed temozolomide/PLGA/nano-hydroxyapatite microspheres, as controlled drug release carriers, have promising potential in treating glioma. PMID:22312307

  7. Pharmacokinetic study of furosemide incorporated PLGA microspheres after oral administration to rat

    PubMed Central

    Derakhshandeh, Katayoun; Karimi, Moin; Azandaryani, Abbas Hemati; Bahrami, Gholamreza; Ghanbari, Kiumras

    2016-01-01

    Objective(s): The purpose of the current study was to assess the feasibility of microspheres from biocompatible polymer for oral bioavailability (BA) enhancement of potent sulfonamide- type loop diuretic- Furosemide - which used in the treatment of congestive heart failure, caused edema, cirrhosis, renal disease and as an adjunct in acute pulmonary edema. The comparatively poor and inconstant BA of furosemide, which occurs site-specifically in the stomach and upper small intestine, has been ascribed to the poor dissolution of furosemide. Materials and Methods: In attempt to enhance the drug BA, poly (dl-lactic-co-glycolic acid) (PLGA) microspheres of furosemide were obtained using solvent-evaporation method and the carrier characteristics were investigated subsequently. Results: The in vivo performance of optimum formulation was assessed by pharmacokinetic evaluation of drug after orally administration of free and loaded in microspheres to rats (4 mg/Kg). For this reason, the concentration of drug in plasma was measured by a new developed and sensitive method of HPLC. Acceptable drug loading and encapsulation efficiency of microspheres were obtained to be 70.43 and 85.21 %, respectively. Microspheres provided improved pharmacokinetic parameters (Cmax = 147.94 ng/ml, Tmax = 1.92 hr) in rats as compared with pure drug (Cmax = 75.69 ng/ml, Tmax = 1.5 hr). The obtained AUC of drug in microsphere was 10 fold higher than of the free drug. Conclusion: The results showed that the prepared microspheres successfully improved BA of the poorly water-soluble drug effectively. PMID:27872700

  8. Effect of polymer porosity on aqueous self-healing encapsulation of proteins in PLGA microspheres.

    PubMed

    Reinhold, Samuel E; Schwendeman, Steven P

    2013-12-01

    Self-healing (SH) poly(lactic-co-glycolic acid) (PLGA) microspheres are a unique class of functional biomaterials capable of microencapsulating process-sensitive proteins by simple mixing and heating the drug-free polymer in aqueous protein solution. Drug-free SH microspheres of PLGA 50/50 with percolating pore networks of varying porosity (ϵ = 0.49-73) encapsulate increasing lysozyme (≈1 to 10% w/w) with increasing ϵ, with typically ≈20 to 25% pores estimated accessible to entry by the enzyme from the external solution. Release kinetics of lysozyme under physiological conditions is continuous over more than two weeks and most strongly influenced by ϵ and protein loading before reaching a lag phase until 28 d at the study completion. Recovered enzyme after release is typically predominantly monomeric and active. Formulations containing acid-neutralizing MgCO3 at ≥ 4.3% exhibit >97% monomeric and active protein after the release with full mass balance recovery. Hence, control of SH polymer ϵ is a key parameter to development of this new class of biomaterials.

  9. Magnetic field activated drug release system based on magnetic PLGA microspheres for chemo-thermal therapy.

    PubMed

    Fang, Kun; Song, Lina; Gu, Zhuxiao; Yang, Fang; Zhang, Yu; Gu, Ning

    2015-12-01

    Controlled drug delivery systems have been extensively investigated for cancer therapy in order to obtain better specific targeting and therapeutic efficiency. Herein, we developed doxorubicin-loaded magnetic PLGA microspheres (DOX-MMS), in which DOX was encapsulated in the core and high contents (28.3 wt%) of γ-Fe2O3 nanoparticles (IOs) were electrostatically assembled on the surface of microsphere to ensure the high sensitivity to response of an external alternating current magnetic field (ACMF). The IOs in PLGA shell can both induce the heat effect and trigger shell permeability enhancement to release drugs when DOX-MMs was activated by ACMF. Results show that the cumulative drug release from DOX-MMs exposed to ACMF for 30 min (21.6%) was significantly higher (approximately 7 times higher) than that not exposed to ACMF (2.8%). The combination of hyperthermia and enhanced DOX release from DOX-MMS is beneficial for in vitro 4T1 breast cancer cell apoptosis as well as effective inhibition of tumor growth in 4T1 tumor xenografts. Therefore, the DOX-MMS can be optimized as powerful delivery system for efficient magnetic responsive drug release and chemo-thermal therapy.

  10. Effect of WOW process parameters on morphology and burst release of FITC-dextran loaded PLGA microspheres.

    PubMed

    Mao, Shirui; Xu, Jing; Cai, Cuifang; Germershaus, Oliver; Schaper, Andreas; Kissel, Thomas

    2007-04-04

    Using fluorescein isothiocyanate labeled dextran (FITC-dextran 40, FD40) as a hydrophilic model compound, microspheres were prepared by a WOW double emulsion technique. Influence of process parameters on microsphere morphology and burst release of FD40 from PLGA microspheres was studied. Internal morphology of microspheres was investigated by stereological method via cryo-cutting technique and scanning electron microscopy (SEM). Drug distribution in microspheres was observed with confocal laser scanning microscopy (CLSM). Polymer nature (RG503 and RG503H) had significant influence on the micro-morphology of microspheres. Increase in continuous water phase volume (W2) led to increased surface porosity but decreased internal porosity. By increasing PVA concentration in the continuous phase from 0.1 to 1%, particle size changed marginally but burst release decreased from 12.2 to 5.9%. Internal porosity of microspheres decreased considerably with increasing polymer concentration. Increase in homogenization speed during the primary emulsion preparation led to decreased internal porosity. Burst release decreased with increasing drug loading but increased with drug molecular weight. Drug distribution in microspheres depended on preparation method. The porosity of microspheres decreased with time in the diffusion stage, but internal morphology had no influence on the release behavior in the bioerosion stage. In summary, surface porosity and internal morphology play a significant role in the release of hydrophilic macromolecules from biodegradable microspheres in the initial release phase characterized by pore diffusion.

  11. Sustained delivery of rhBMP-2 via PLGA microspheres: cranial bone regeneration without heterotopic ossification or craniosynostosis

    PubMed Central

    Wink, Jason D.; Gerety, Patrick A.; Sherif, Rami D.; Lim, Youngshin; A.Clarke, Nadya; Rajapakse, Chamith S.; Nah, Hyun-Duck; Taylor, Jesse A.

    2014-01-01

    Background Commercially available recombinant human bone morphogenetic protein 2 (rhBMP2) has demonstrated efficacy in bone regeneration, but not without significant side effects. In this study, we utilize rhBMP2 encapsulated in PLGA microspheres (PLGA-rhBMP2) placed in a rabbit cranial defect model to test whether low-dose, sustained, delivery can effectively induce bone regeneration. Methods rhBMP2 was encapsulated in 15% poly (lactic-co-glycolic acid), using a double emulsion, solvent extraction/evaporation technique, and its release kinetics and bioactivity were tested. Two critical-size defects (10mm) were created in the calvarium of New Zealand White rabbits (5-7 mos of age, M/F) and filled with a collagen scaffold containing one of four groups: 1) no implant, 2) collagen scaffold only, 3) PLGA-rhBMP2(0.1ug/implant), or 4) free rhBMP2 (0.1ug/implant). After 6 weeks, the rabbits were sacrificed and defects were analyzed by μCT, histology, and finite element analysis. Results RhBMP2 delivered via bioactive PLGA microspheres resulted in higher volumes and surface area coverage of new bone than an equal dose of free rhBMP2 by μCT and histology (p=0.025, 0.025). FEA indicated that the mechanical competence using the regional elastic modulus did not differ with rhBMP2 exposure (p=0.70). PLGA-rhBMP2 did not demonstrate heterotopic ossification, craniosynostosis, or seroma formation. Conclusions Sustained delivery via PLGA microspheres can significantly reduce the rhBMP2 dose required for de novo bone formation. Optimization of the delivery system may be a key to reduce the risk for recently reported rhBMP2 related adverse effects. Level of Evidence Animal Study PMID:24622573

  12. MAPs/bFGF-PLGA microsphere composite-coated titanium surfaces promote increased adhesion and proliferation of fibroblasts.

    PubMed

    Wang, Zhongshan; Wu, Guofeng; Bai, Shizhu; Feng, Zhihong; Dong, Yan; Zhou, Jian; Qin, Haiyan; Zhao, Yimin

    2014-06-01

    Infection and epithelial downgrowth are two major problems with maxillofacial transcutaneous implants, and both are mainly due to lack of stable closure of soft tissues at transcutaneous sites. Fibroblasts have been shown to play a key role in the formation of biological seals. In this work, titanium (Ti) model surfaces were coated with mussel adhesive proteins (MAPs) utilizing its unique adhesion ability on diverse inorganic and organic surfaces in wet environments. Prepared basic fibroblast growth factor (bFGF)-poly(lactic-co-glycolic acid) (PLGA) microspheres can be easily synthesized and combined onto MAPs-coated Ti surfaces, due to the negative surface charges of microspheres in aqueous solution, which is in contrast to the positive charges of MAPs. Titanium model surfaces were divided into three groups. Group A: MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces. Group B: MAPs-coated Ti surfaces. Group C: uncoated Ti surfaces. The effects of coated Ti surfaces on adhesion of fibroblasts, cytoskeletal organization, proliferation, and extracellular matrix (ECM)-related gene expressions were examined. The results revealed increased adhesion (P < 0.05), enhanced actin cytoskeletal organization, and up-regulated ECM-related gene expressions in groups A and B compared with group C. Increased proliferation of fibroblasts during five days of incubation was observed in group A compared with groups B and C (P < 0.05). Collectively, the results from this in vitro study demonstrated that MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces had the ability to increase fibroblast functionality. In addition, MAPs/bFGF-PLGA microsphere composite-coated Ti surfaces should be studied further as a method of promoting formation of stable biological seals around transcutaneous sites.

  13. A novel and simple preparative method for uniform-sized PLGA microspheres: Preliminary application in antitubercular drug delivery.

    PubMed

    Liu, Zhiqiang; Li, Xia; Xiu, Bingshui; Duan, Cuimi; Li, Jiangxue; Zhang, Xuhui; Yang, Xiqin; Dai, Wenhao; Johnson, Heather; Zhang, Heqiu; Feng, Xiaoyan

    2016-09-01

    Particle size has been demonstrated as a key parameter influencing the phagocytosis of drug-loaded PLGA microspheres (MS) by the target cells. However, the current preparative methods were either insufficient in controlling the homogeneity of the produced MS, or requires sophisticated and costly equipment. This study aimed to explore a simple and economical method for uniform PLGA MS preparation. Based on the heterogeneous emulsification of routine mechanical stirring, we designed an adjuvant strategy to enhance the homogeneity of MS. By using glass beads as adjutant, the dispersion produced during mechanical stirring was much more homogeneous in the solution. The particles produced were much smaller and the size distribution was much narrower as compared with those produced using the routine mechanical stirring method under the same condition. After enrichment by selective centrifugation, about 60% of the particles of similar size were obtained, providing further evidence for the efficiency of the novel method in controlling particle homogeneity. Further, the method was applied to prepare rifampicin-loaded PLGA MS of the optimized size for macrophage uptake. The functional evaluation showed that the prepared PLGA MS could efficiently deliver an antitubercular drug into macrophages and maintain a higher intracellular concentration by controlled release, suggesting the potential application of the method in PLGA MS-based drug delivery. Collectively, the study provided a simple and economical method for preparing uniform-sized PLGA MS with potential of widespread applications.

  14. Preparation and characterization of rifampicin-PLGA microspheres/sodium alginate in situ gel combination delivery system.

    PubMed

    Hu, Chunhui; Feng, Hanzhou; Zhu, Chunyan

    2012-06-15

    We prepared a complex drug delivery system consisted of rifampicin-poly(lactic-co-glycolic acid) (PLGA) microspheres in combination with sodium alginate in situ gel. The microspheres were obtained by using a solvent evaporation method, the mean diameter was 1.748 μm and the span of particle distribution was 0.78. The combination delivery system was obtained by adding microspheres to sodium alginate solution followed by physically mixing. In an in vitro study of drug release monitored for 11 days, the release of rifampicin from combination delivery system was slower than microspheres. The cumulative release percent of rifampicin from combination delivery system was 91.83 ± 1.26%, which was lower than 97.36 ± 3.41% of rifampicin released from microspheres. An in vivo fluorescence imaging study suggests that the gel adhered to lungs within 24h, and microspheres stayed in lungs at least for 504 h (21 days). In vivo drug release study indicates that the maximum local rifampicin concentration in lungs was 48.60 ± 15.67 μg mL(-1) 5h after administration. After 21 days, the local rifampicin concentration was 0.81±0.14μgmL(-1), which was above the minimum inhibitory concentration of rifampicin. The combination delivery system significantly prolonged RFP release compared to microspheres, from which RFP released could only be detected for 10 days. This approach to control the release of rifampicin using PLGA microspheres/in situ gel combination delivery system in conjunction with interventional technology is useful for improving anti-tuberculosis treatment effectiveness for patients.

  15. Mechanistic analysis of triamcinolone acetonide release from PLGA microspheres as a function of varying in vitro release conditions.

    PubMed

    Doty, Amy C; Zhang, Ying; Weinstein, David G; Wang, Yan; Choi, Stephanie; Qu, Wen; Mittal, Sachin; Schwendeman, Steven P

    2017-04-01

    In vitro tests for controlled release PLGA microspheres in their current state often do not accurately predict in vivo performance of these products during formulation development. Here, we introduce a new mechanistic and multi-phase approach to more clearly understand in vitro-in vivo relationships, and describe the first "in vitro phase" with the model drug, triamcinolone acetonide (Tr-A). Two microsphere formulations encapsulating Tr-A were prepared from PLGAs of different molecular weights and end-capping (18kDa acid-capped and 54kDa ester-capped). In vitro release kinetics and the evidence for controlling mechanisms (i.e., erosion, diffusion, and water-mediated processes) were studied in four release media: PBST pH 7.4 (standard condition), PBST pH 6.5, PBS+1.0% triethyl citrate (TC), and HBST pH 7.4. The release mechanism in PBST was primarily polymer erosion-controlled as indicated by the similarity of release and mass loss kinetics. Release from the low MW PLGA was accelerated at low pH due to increased rate of hydrolysis and in the presence of the plasticizer TC due to slightly increased hydrolysis and much higher diffusion in the polymer matrix. TC also increased release from the high MW PLGA due to increased hydrolysis, erosion, and diffusion. This work demonstrates how in vitro conditions can be manipulated to change not only rates of drug release from PLGA microspheres but also the mechanism(s) by which release occurs. Follow-on studies in the next phases of this approach will utilize these results to compare the mechanistic data of the Tr-A/PLGA microsphere formulations developed here after recovery of microspheres in vivo. This new approach based on measuring mechanistic indicators of release in vitro and in vivo has the potential to design better, more predictive in vitro release tests for these formulations and potentially lead to mechanism-based in vitro-in vivo correlations.

  16. Tissue distribution of DNA-Hsp65/TDM-loaded PLGA microspheres and uptake by phagocytic cells.

    PubMed

    Trombone, Ana Paula F; Silva, Celio L; Almeida, Luciana P; Rosada, Rogerio S; Lima, Karla M; Oliver, Constance; Jamur, Maria C; Coelho-Castelo, Arlete A M

    2007-09-20

    This study aimed to demonstrate that microspheres, used as delivery vehicle of DNA-Hsp65/TDM [plasmid DNA encoding heat shock protein 65 (Hsp65) coencapsulated with trehalose dimycolate (TDM) into PLGA microspheres], are widely spread among several organs after intramuscular administration in BALB/c mice. In general, we showed that these particles were phagocytosed by antigen presenting cells, such as macrophages and dendritic cells. Besides, it was demonstrated herein that draining lymph node cells presented a significant increase in the number of cells expressing costimulatory molecules (CD80 and CD86) and MHC class II, and also that the administration of the DNA-Hsp65/TDM and vector/TDM formulations resulted in the up-regulation of CD80, CD86 and MHC class II expression when compared to control formulations (vector/TDM and empty). Regarding the intracellular trafficking we observed that following phagocytosis, the microspheres were not found in the late endosomes and/or lysosomes, until 15 days after internalization, and we suggest that these constructions were hydrolysed in early compartments. Overall, these data expand our knowledge on PLGA [poly (lactic-co-glycolic acid)] microspheres as gene carriers in vaccination strategies, as well as open perspectives for their potential use in clinical practice.

  17. Strategies for encapsulation of small hydrophilic and amphiphilic drugs in PLGA microspheres: State-of-the-art and challenges.

    PubMed

    Ramazani, Farshad; Chen, Weiluan; van Nostrum, Cornelis F; Storm, Gert; Kiessling, Fabian; Lammers, Twan; Hennink, Wim E; Kok, Robbert J

    2016-02-29

    Poly(lactide-co-glycolide) (PLGA) microspheres are efficient delivery systems for controlled release of low molecular weight drugs as well as therapeutic macromolecules. The most common microencapsulation methods are based on emulsification procedures, in which emulsified droplets of polymer and drug solidify into microspheres when the solvent is extracted from the polymeric phase. Although high encapsulation efficiencies have been reported for hydrophobic small molecules, encapsulation of hydrophilic and/or amphiphilic small molecules is challenging due to the partitioning of drug from the polymeric phase into the external phase before solidification of the particles. This review addresses formulation-related aspects for efficient encapsulation of small hydrophilic/amphiphilic molecules into PLGA microspheres using conventional emulsification methods (e.g., oil/water, water/oil/water, solid/oil/water, water/oil/oil) and highlights novel emulsification technologies such as microfluidics, membrane emulsification and other techniques including spray drying and inkjet printing. Collectively, these novel microencapsulation technologies afford production of this type of drug loaded microspheres in a robust and well controlled manner.

  18. Encapsulation of Exenatide in Poly-(d,l-Lactide-Co-Glycolide) Microspheres Produced an Investigational Long-Acting Once-Weekly Formulation for Type 2 Diabetes

    PubMed Central

    MacConell, Leigh; Sarin, Viren; Trautmann, Michael; Herbert, Paul

    2011-01-01

    Abstract Exenatide once-weekly (EQW [2 mg s.c.]) is under development as monotherapy as an adjunct to diet and exercise or as a combination therapy with an oral antidiabetes drug(s) in adults with type 2 diabetes. This long-acting formulation contains the active ingredient of the original exenatide twice-daily (EBID) formulation encapsulated in 0.06-mm-diameter microspheres of medical-grade poly-(d,l-lactide-co-glycolide) (PLG). After mechanical suspension and subcutaneous injection by the patient, EQW microspheres hydrate in situ and adhere to one another to form an amalgam. A small amount of loosely bound surface exenatide, typically less than 1%, releases in the first few hours, whereas drug located in deeper interstices diffuses out more slowly (time to maximum, ∼2 weeks). Fully encapsulated exenatide (i.e., drug initially inaccessible to diffusion) releases over a still longer period (time to maximum, ∼7 weeks) as the PLG matrix hydrolyzes into lactic acid and glycolic acid, which are subsequently eliminated as carbon dioxide and water. For EQW, plasma exenatide concentrations reach the therapeutic range by 2 weeks and steady state by 6–7 weeks. This gradual approach to steady state seems to improve tolerability, as nausea is less frequent with EQW than EBID. EQW administrations may be associated with palpable skin nodules that generally resolve without further medical intervention. In comparative trials, EQW improved hemoglobin A1c more than EBID, sitagliptin, pioglitazone, or insulin glargine and reduced fasting plasma glucose more than EBID. Weight loss due to EQW or EBID was similar. EQW is the first glucose-lowering agent that is administered once weekly. PMID:21751887

  19. Controlling Acute Inflammation with Fast Releasing Dexamethasone-PLGA Microsphere/PVA Hydrogel Composites for Implantable Devices

    PubMed Central

    Bhardwaj, Upkar; Sura, Radhakrishna; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2007-01-01

    Background Continuous release of dexamethasone from PLGA microsphere/PVA hydrogel composites has been shown to suppress the inflammatory tissue reaction in response to subcutaneously implanted foreign material for a period of one month. The scope of the present work is to investigate whether suppressing the initial acute inflammatory phase with fast releasing dexamethasone-PLGA microsphere/PVA composites (that release the drug over a period of one week) would prevent the development of a foreign body reaction in response to implantation in the subcutaneous tissue using a rat model. Methods Dexamethasone loaded PLGA microspheres were prepared using the solvent evaporation method. In vitro release from microspheres was analyzed using USP apparatus 4 in phosphate buffered saline (PBS) at 37°C. Composites were fabricated in 18G needles by freeze-thaw cycling the PVA/microsphere dispersion. The composites were implanted in the subcutaneous tissue of anesthetized rats. The pharmacodynamic effect was evaluated by histological examination of the tissue surrounding the composites at pre-determined time points. Results In vitro release studies showed that most of the drug entrapped in the microspheres was released within one week. At days 3 and 8, these fast releasing dexamethasone containing composites suppressed the acute phase of inflammation but did not prevent the development of an inflammatory reaction after dexamethasone was completely released from the composites. By day 30, chronic inflammation and fibrosis were observed in the tissue surrounding the drug-containing composites. On days 3 and 8, the number of inflammatory cells in the vicinity of the dexamethasone containing composites was similar to that in normal tissue. However, the number of inflammatory cells was higher in drug-containing composites as compared to drug-free composites by day 30. This was due to the inflammation being in a more advanced stage in drug-free composites where a granulomatous

  20. Protective efficacy of PLGA microspheres loaded with divalent DNA vaccine encoding the ompA gene of Aeromonas veronii and the hly gene of Aeromonas hydrophila in mice.

    PubMed

    Gao, Shanshan; Zhao, Na; Amer, Said; Qian, Mingming; Lv, Mengxi; Zhao, Yuliang; Su, Xin; Cao, Jieying; He, Hongxuan; Zhao, Baohua

    2013-11-19

    In the present study, poly (lactic-co-glycolic) acid (PLGA) was used as a carrier for a divalent fusion DNA vaccine encoding the Aeromonas veronii outer membrane protein A (ompA) and Aeromonas hydrophila hemolysins (hly) protein. The recombinant pET-28a-ompA-hly was constructed by inserting the ompA gene and hly gene into a pET-28a expression vector. Loading of ompA-hly antigen module on PLGA microspheres were accomplished by water-in-oil-in-water (W/O/W) encapsulation. The molecular weight and specificity of pET-28a-ompA-hly were detected by dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. The microspheres showed an average particle size of 100-150 μm and a loading efficiency (LE) of 68.8%. Mice received ompA-hly antigen-loaded PLGA microspheres by intraperitoneal or intragastric administration mounted strong and sustained IgG response, which was significantly higher (p<0.05) than those achieved by pET-28a-ompA-hly antigen alone. OmpA-hly antigen-loaded PLGA microsphere vaccine uniquely conferred a long lasting (30 days) sterile immunity against challenge infection. Results indicated that ompA-hly antigen-loaded PLGA microsphere vaccine is a qualified candidate vector system for sterile protective immunity against A. hydrophila and A. veronii infections.

  1. Efficacy of Ropinirole-Loaded PLGA Microspheres For The Reversion Of Rotenone-Induced Parkinsonism.

    PubMed

    Negro, Sofía; Boeva, Liudmilla; Slowing, Karla; Fernández-Carballido, Ana; García-García, Luis; Barcia, Emilia

    2016-09-28

    A new controlled delivery system is developed for ropinirole (RP) for the treatment of Parkinson´s disease (PD) consisting in PLGA microparticles (MPs) which exhibited in vitro constant release of RP (78.23 µg/day/10 mg MPs) for 19 days. The neuroprotective effects of RP released from MPs are evaluated in SKN-AS cells after exposure to rotenone (20 μM). Cell apoptosis was significantly reduced by RP (100-120 μM). Daily doses of rotenone (2 mg/kg) given i.p. to rats induced neuronal and behavioral changes similar to those of PD. After 15 days animals received RP in saline (1 mg/kg/day for 45 days) or as MPs at two dose levels (amount of MPs equivalent to 7.5 mg/kg or 15 mg/kg RP given on days 15 and 30). Brain immunochemistry (Nissl-staining, GFAP and TH immunohistochemistry) and behavioral testing (catalepsy, akinesia, rotarod and swim test) showed that animals receiving RP either in solution or encapsulated within MPs reverted PD symptoms with the best results obtained in animals receiving RP microspheres at the highest dose assayed, thereby confirming the potential therapeutic interest of the new RP delivery system.

  2. Preparation, Characterization, In Vitro Release and Degradation of Cathelicidin-BF-30-PLGA Microspheres

    PubMed Central

    Li, Hongli; Yuan, Mingwei; Yuan, Minglong

    2014-01-01

    Cathelicidin-BF-30 (BF-30), a water-soluble peptide isolated from the snake venom of Bungarus fasciatus containing 30 amino acid residues, was incorporated in poly(D,L-lactide-co-glycolide) (PLGA) 75∶25 microspheres (MS) prepared by a water in oil in water W/O/W emulsification solvent extraction method. The aim of this work was to investigate the stability of BF-30 after encapsulation. D-trehalose was used as an excipient to stabilize the peptide. The MS obtained were mostly under 2 µm in size and the encapsulation efficiency was 88.50±1.29%. The secondary structure of the peptide released in vitro was determined to be nearly the same as the native peptide using Circular Dichroism (CD). The ability of BF-30 to inhibit the growth of Escherichia coli was also maintained. The cellular relative growth and hemolysis rates were 92.16±3.55% and 3.52±0.45% respectively. PMID:24963652

  3. Preparation of uniform-sized exenatide-loaded PLGA microspheres as long-effective release system with high encapsulation efficiency and bio-stability.

    PubMed

    Qi, Feng; Wu, Jie; Fan, Qingze; He, Fan; Tian, Guifang; Yang, Tingyuan; Ma, Guanghui; Su, Zhiguo

    2013-12-01

    Exenatide-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres hold great potential as a drug delivery system to treat type 2 diabetes mellitus (T2DM) because they can overcome the shortcoming of exenatide's short half-life and realize sustained efficacy. However, conventional preparation methods often lead to microspheres with a broad size distribution, which in turn would cause poor preparation repeatability, drug efficacy and so forth. In this study, we used Shirasu Porous Glass (SPG) premix membrane emulsification technique characterized with high trans-membrane flux and size controllability to prepare uniform-sized PLGA microspheres. By optimizing trans-membrane pressure and PVA concentration in external aqueous phase, uniform-sized PLGA microspheres with large size (around 20μm) were successfully obtained. To achieve high encapsulation efficiency (EE) and improve in vitro release behavior, we have carefully examined the process parameters. Our results show that using ultrasonication to form primary emulsion, microspheres with high EE were easily obtained, but the rate of in vitro release was very slow. Instead, high EE and appropriate in vitro release were achieved when homogenization with optimized time and speed were employed. Besides, we also systematically investigated the effect of formulations on loading efficiency (LE) as well as the relationship between the resultant size of the microspheres and pore size of the membrane. Finally, through RP-HPLC and CD spectra analysis, we have demonstrated that the bio-stability of exenatide in microspheres was preserved during the preparation process.

  4. In vitro and in vivo evaluation of calcium phosphate composite scaffolds containing BMP-VEGF loaded PLGA microspheres for the treatment of avascular necrosis of the femoral head.

    PubMed

    Zhang, Hao-Xuan; Zhang, Xiu-Ping; Xiao, Gui-Yong; Hou, Yong; Cheng, Lei; Si, Meng; Wang, Shuai-Shuai; Li, Yu-Hua; Nie, Lin

    2016-03-01

    Avascular necrosis of the femoral head (ANFH) is difficult to treat due to high pressure and hypoxia, and reduced levels of growth factors such as bone morphogenetic protein (BMP), and vascular endothelial growth factor (VEGF). We generated a novel calcium phosphate (CPC) composite scaffold, which contains BMP-VEGF-loaded poly-lactic-co-glycolic acid (PLGA) microspheres (BMP-VEGF-PLGA-CPC). The BMP-VEGF-loaded microspheres have an encapsulation efficiency of 89.15% for BMP, and 78.55% for VEGF. The BMP-VEGF-PLGA-CPC scaffold also demonstrated a porosity of 62% with interconnected porous structures, and pore sizes of 219 μm and compressive strength of 6.60 MPa. Additionally, bone marrow mesenchymal stem cells (BMSCs) were seeded on scaffolds in vitro. Further characterization showed that the BMP-VEGF-PLGA-CPC scaffolds were biocompatible and enhanced osteogenesis and angiogenesis in vitro. Using a rabbit model of ANFH, BMP-VEGF-PLGA-CPC scaffolds were implanted into the bone tunnels of core decompression in the femoral head for 6 and 12 weeks. Radiographic and histological analysis demonstrated that the BMP-VEGF-PLGA-CPC scaffolds exhibited good biocompatibility, and osteogenic and angiogenic activity in vivo. These results indicate that the BMP-VEGF-PLGA-CPC scaffold may improve the therapeutic effect of core decompression surgery and be used as a treatment for ANFH.

  5. PEG-derivative effectively modifies the characteristics of indomethacin-PLGA microspheres destined to intra-articular administration.

    PubMed

    Puebla, Patricia; Pastoriza, Pilar; Barcia, Emilia; Fernández-Carballido, Ana

    2005-11-01

    The aim of this study was to obtain biodegradable indomethacin microspheres for intra-articular administration in rheumatoid arthritis, where angiogenic processes are involved. Indomethacin concentrations to achieve an anti-angiogenic effect would be five-times higher than an anti-inflammatory. Microspheres were prepared by solvent evaporation using PLGA. Indomethacin is a poor water-soluble drug with it being possible that dissolved and non-dissolved drug co-exist within the polymeric matrix resulting in rapid release. To control this release, an oil-PEG-derivative was incorporated, producing changes in morphology, crystallinity and indomethacin release. To minimize the amount of microspheres administered, a two-factor five-level central rotable composite 2(2)+star design was employed with two independent variables: indomethacin percentage and PEG-derivative percentage. The optimum formulation showed mean encapsulation efficiency of 94.3+/-2.2% and released 7.99+/-0.25 microg indomethacin/day/mg microspheres for 21 days. A dose of 20-50 mg of this formulation could be appropriate to achieve both anti-angiogenic and anti-inflammatory effects. Preliminary cytotoxicity studies performed in rat splenocytes showed an adequate cell viability.

  6. Characterization of the release profile of doxycycline by PLGA microspheres adjunct to non-surgical periodontal therapy.

    PubMed

    Moura, Lucas Alves; Ribeiro, Fernanda Vieira; Aiello, Talita Bianchi; Duek, Eliana Ap De Rezende; Sallum, Enilson Antonio; Nociti Junior, Francisco Humberto; Casati, Márcio Zaffalon; Sallum, Antonio Wilson

    2015-01-01

    The aim of this pilot study was to assess the release of locally delivered doxycycline by poly (l-lactide-co-glycolide) (PLGA) microspheres in the periodontal pocket of patients with chronic periodontitis, treated by non-surgical periodontal therapy. Nineteen sites of non-adjacent teeth of four different patients were evaluated. Five milligram of PLGA microspheres loaded with 16 doxycycline hyclate (DOX) was administered per periodontal site. To quantify DOX released into the periodontal pocket, gingival crevicular fluid (GCF) was collected from the sites on days 2, 5, 7, 10, 15, and 20 after DOX application, and high-performance liquid chromatography was performed. Data were statistically assessed by ANOVA/Tukey test. At days 2, 5, and 7, the DOX concentration was stably sustained (23.33 ± 1.38, 23.4 ± 1.82, and 22.75 ± 1.33 μg/mL, respectively), with no significant differences over these assessment times (p > 0.05). At days 10 and 15, a tendency was observed toward a decrease in DOX concentration (21.74 ± 0.91 and 20.53 ± 4.88 μg/mL, respectively), but a significant decrease in GCF drug concentration (19.69 ± 4.70 μg/mL) was observed only on day 20. The DOX delivery system developed demonstrated a successful sustained release after local administration, as an adjunct to non-surgical periodontal therapy.

  7. Effect of cyclodextrins on alpha-chymotrypsin stability and loading in PLGA microspheres upon S/O/W encapsulation.

    PubMed

    Castellanos, Ingrid J; Flores, Giselle; Griebenow, Kai

    2006-04-01

    The potential of cyclodextrins to stabilize alpha-chymotrypsin upon encapsulation in Poly(lactic-co-glycolic) acid (PLGA) microspheres using a solid-in-oil-in-water (s/o/w) technique was investigated. Two cyclodextrins, hydroxyl-propyl-beta-cyclodextrin (HPbetaCD) and methyl-beta-cyclodextrin (MbetaCD), one insoluble and the other soluble in methylene chloride, were used. The results demonstrate that HPbetaCD failed to stabilize alpha-chymotrypsin upon encapsulation. Specifically, 19% of the protein was aggregated and the specific activity of the enzyme was reduced to ca. 50% of that prior to encapsulation. In contrast, MbetaCD significantly decreased the formation of aggregates to 3% and the retained specific activity of the enzyme was approximately 90%. The co-lyophilization of alpha-chymotrypsin with MbetaCD prior to encapsulation was a requisite to preserve the protein stability in microspheres. Furthermore, MbetaCD prevented the loss of protein during the preparation of microspheres and the encapsulation efficiency was improved to 90%. Release experiments showed the use of MbetaCD modified the release profile: the burst release decreased from 54% (in the absence of the excipient) to 36%. The results suggest that MbetaCD might be a suitable excipient to improve protein stability in s/o/w encapsulation procedures.

  8. Gas-generating TPGS-PLGA microspheres loaded with nanoparticles (NIMPS) for co-delivery of minicircle DNA and anti-tumoral drugs.

    PubMed

    Gaspar, Vítor M; Moreira, André F; Costa, Elisabete C; Queiroz, João A; Sousa, Fani; Pichon, Chantal; Correia, Ilídio J

    2015-10-01

    Drug-DNA combination therapies are receiving an ever growing focus due to their potential for improving cancer treatment. However, such approaches are still limited by the lack of multipurpose delivery systems that encapsulate drugs and condense DNA simultaneously. In this study, we describe the successful formulation of gas-generating pH-responsive D-α-tocopherol PEG succinate-poly(D,L-lactic-co-glycolic acid) (TPGS-PLGA) hollow microspheres loaded with both Doxorubicin (Dox) and minicircle DNA (mcDNA) nanoparticles as a strategy to co-deliver these therapeutics. For this study mcDNA vectors were chosen due to their increased therapeutic efficiency in comparison to standard plasmid DNA. The results demonstrate that TPGS-PLGA microcarriers can encapsulate Dox and chitosan nanoparticles completely condense mcDNA. The loading of mcDNA-nanoparticles into microspheres was confirmed by 3D confocal microscopy and co-localization analysis. The resulting TPGS-PLGA-Dox-mcDNA nanoparticle-in-microsphere hybrid carriers exhibit a well-defined spherical shape and neutral surface charge. Microcarriers incubation in acidic pH produced a gas-mediated Dox release, corroborating the microcarriers stimuli-responsive character. Also, the dual-loaded TPGS-PLGA particles achieved 5.2-fold higher cellular internalization in comparison with non-pegylated microspheres. This increased intracellular concentration resulted in a higher cytotoxic effect. Successful transgene expression was obtained after nanoparticle-mcDNA co-delivery in the microspheres. Overall these findings support the concept of using nanoparticle-microsphere multipart systems to achieve efficient co-delivery of various drug-mcDNA combinations.

  9. Immune Augmentation of Single Contact Hepatitis B Vaccine by Using PLGA Microspheres as an Adjuvant.

    PubMed

    Sivakumar, S M; Sukumaran, N; Murugesan, R; Shanmugarajan, T S; Anbu, J; Sivakumar, L; Anilbabu, B; Srinivasarao, G; Ravichandran, V

    2008-01-01

    The present study was aimed to replace the alum type adjuvant for hepatitis B vaccine. The hepatitis B vaccine was encapsulated in poly (DL-lactide-co-glycolide) microspheres by solvent evaporation technique. The formulated microspheres were characterized in terms of morphology, particle size analysis, in vitro release study and in vivo immune response in male Wistar rats. The FT IR spectrum illustrates the characteristics bands of poly (DL-lactide-co-glycolide) microspheres and hepatitis B vaccine at 1750 cm(-1) and 1650 cm(-1), respectively. The hepatitis B vaccine loaded poly (DL-lactide-co-glycolide) microspheres were able to release antigens till day 42. Significant enhancement of specific antibodies to HBsAg was produced till day 90 after a single administration of HBsAg encapsulated poly (DL-lactide-co-glycolide) microspheres. However, the conventional alum adsorbed hepatitis B vaccine was not found to produce any significant specific antibody levels till day 90 after a single dose. The results showed that poly (DL-lactide-co-glycolide) microspheres show potential as an adjuvant for hepatitis B vaccine.

  10. HPLC-UV method development and validation for the quantification of ropinirole in new PLGA multiparticulate systems: Microspheres and nanoparticles.

    PubMed

    Fuster, J; Negro, S; Salama, A; Fernández-Carballido, A; Marcianes, P; Boeva, L; Barcia, E

    2015-08-01

    A simple HPLC-UV method was developed and validated for the quantitation of RP free base encapsulated into two new multiparticulate systems (microparticles and nanoparticles), as well as for the quantification of RP hydrochloride when given as a loading dose together with the new delivery system developed. HPLC separation was achieved using a C18 Kromasil column (250 mm × 4 mm) with a mobile phase composed of acetonitrile-phosphate buffer solution (55:45, v/v) adjusted at pH 6.0 and containing 0.3% triethanolamine. Flow rate was set at 1.0 mL min(-1). The UV detector was operated at 245 nm. The method allowed for the simultaneous determination of both RP and RP-HCl. The method was linear within the range 2.5-50 μg mL(-1) for both RP and RP-HCl. The limits of detection (LOD) and quantitation (LOQ) found were 0.8 μg mL(-1) and 2.4 μg mL(-1) for RP, and 0.3 μg mL(-1) and 0.9 μg mL(-1) for RP-HCl. The method was found to be simple, rapid, specific, precise, accurate, and reproducible. The method was successfully applied to the determination of the encapsulation efficiency of RP in the multiparticulate systems developed, being 85.03 ± 3.77% and 51.12 ± 3.50%, for RP-loaded PLGA microspheres and RP-loaded PLGA nanoparticles, respectively.

  11. Release of a Wound-healing Agent from PLGA Microspheres in a Thermosensitive Gel

    DTIC Science & Technology

    2013-01-01

    and K. P. Leung1 1 US Army Dental and Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Building 3610, JBSA Fort Sam...loaded microspheres into a thermoreversible gel would provide a novel platform in the treatment of persistent infections arising from localized biofilms ...most prevalent bacteria found on human skin and mucous membrane microbial flora, has emerged as major source of nosocomial infections of implanted

  12. Microspheres prepared with different co-polymers of poly(lactic-glycolic acid) (PLGA) or with chitosan cause distinct effects on macrophages.

    PubMed

    Bitencourt, Claudia da Silva; Silva, Letícia Bueno da; Pereira, Priscilla Aparecida Tartari; Gelfuso, Guilherme Martins; Faccioli, Lúcia Helena

    2015-12-01

    Microencapsulation of bioactive molecules for modulating the immune response during infectious or inflammatory events is a promising approach, since microspheres (MS) protect these labile biomolecules against fast degradation, prolong the delivery over longer periods of time and, in many situations, target their delivery to site of action, avoiding toxic side effects. Little is known, however, about the influence of different polymers used to prepare MS on macrophages. This paper aims to address this issue by evaluating in vitro cytotoxicity, phagocytosis profile and cytokines release from alveolar macrophages (J-774.1) treated with MS prepared with chitosan, and four different co-polymers of PLGA [poly (lactic-co-glycolic acid)]. The five MS prepared presented similar diameter and zeta potential each other. Chitosan-MS showed to be cytotoxic to J-774.1 cells, in contrast to PLGA-MS, which were all innocuous to this cell linage. PLGA 5000-MS was more efficiently phagocytized by macrophages compared to the other MS tested. PLGA 5000-MS and 5002-MS induced significant production of TNF-α, while 5000-MS, 5004-MS and 7502-MS decreased spontaneous IL-6 release. Nevertheless, only PLGA 5002-MS induced significant NFkB/SEAP activation. These findings together show that MS prepared with distinct PLGA co-polymers are differently recognized by macrophages, depending on proportion of lactic and glycolic acid in polymeric chain, and on molecular weight of the co-polymer used. Selection of the most adequate polymer to prepare a microparticulate drug delivery system to modulate immunologic system may take into account, therefore, which kind of immunomodulatory response is more adequate for the required treatment.

  13. Modeling the Time Course of the Tissue Responses to Intramuscular Long-acting Paliperidone Palmitate Nano-/Microcrystals and Polystyrene Microspheres in the Rat.

    PubMed

    Darville, Nicolas; van Heerden, Marjolein; Erkens, Tim; De Jonghe, Sandra; Vynckier, An; De Meulder, Marc; Vermeulen, An; Sterkens, Patrick; Annaert, Pieter; Van den Mooter, Guy

    2016-02-01

    Long-acting injectable (LAI) drug suspensions consist of drug nano-/microcrystals suspended in an aqueous vehicle and enable prolonged therapeutic drug exposure up to several months. The examination of injection site reactions (ISRs) to the intramuscular (IM) injection of LAI suspensions is relevant not only from a safety perspective but also for the understanding of the pharmacokinetics. The aim of this study was to perform a multilevel temporal characterization of the local and lymphatic histopathological/immunological alterations triggered by the IM injection of an LAI paliperidone palmitate suspension and an analog polystyrene suspension in rats and identify critical time points and parameters with regard to the host response. The ISRs showed a moderate to marked chronic granulomatous inflammation, which was mediated by multiple cyto-/chemokines, including interleukin-1β, monocyte Chemoattractant Protein-1, and vascular endothelial growth factor. Lymphatic uptake and lymph node retention of nano-/microparticles were observed, but the contribution to the drug absorption was negligible. A simple image analysis procedure and empirical model were proposed for the accurate evaluation of the depot geometry, cell infiltration, and vascularization. This study was designed as a reference for the evaluation and comparison of future LAIs and to support the mechanistic modeling of the formulation-physiology interplay regulating the drug absorption from LAIs.

  14. Porous nano-hydroxyapatite/collagen scaffold containing drug-loaded ADM-PLGA microspheres for bone cancer treatment.

    PubMed

    Rong, Zi-Jie; Yang, Lian-Jun; Cai, Bao-Ta; Zhu, Li-Xin; Cao, Yan-Lin; Wu, Guo-Feng; Zhang, Zan-Jie

    2016-05-01

    To develop adriamycin (ADM)-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a porous nano-hydroxyapatite/collagen scaffold (ADM-PLGA-NHAC). To provide novel strategies for future treatment of osteosarcoma, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of ADM-PLGA-NHAC on the osteosarcoma MG63 cells, and its bone repair capacity, were investigated in vivo and in vitro. The PLGA copolymer was utilized as a drug carrier to deliver ADM-PLGA nanoparticles (ADM-PLGA-NP). Porous nano-hydroxyapatite and collagen were used to materials to produce the porous nano-hydroxyapatite/collagen scaffold (NHAC), into which the ADM-PLGA-NP was loaded. The performance of the drug-carrying scaffold was assessed using multiple techniques, including scanning electron microscopy and in vitro extended release. The antineoplastic activities of scaffold extracts on the human osteosarcoma MG63 cell line were evaluated in vitro using the cell counting kit-8 (CCK8) method and live-dead cell staining. The bone repair ability of the scaffold was assessed based on the establishment of a femoral condyle defect model in rabbits. ADM-PLGA-NHAC and NHAC were implanted into the rat muscle bag for immune response experiments. A tumor-bearing nude mice model was created, and the TUNEL and HE staining results were observed under optical microscopy to evaluate the antineoplastic activity and toxic side effects of the scaffold. The composite scaffold demonstrated extraordinary extended-release properties, and its extracts also exhibited significant inhibition of the growth of osteosarcoma MG63 cells. In the bone repair experiment, no significant difference was observed between ADM-PLGA-NHAC and NHAC by itself. In the immune response experiments, ADM-PLGA-NHAC exhibited remarkable biocompatibility. The in vivo antitumor experiment revealed that the implantation of ADM-PLGA-NHAC in the tumor resulted in a improved antineoplastic

  15. In vitro release study of mono-PEGylated growth hormone-releasing peptide-6 from PLGA microspheres.

    PubMed

    Park, Eun Ji; Na, Dong Hee; Lee, Kang Choon

    2007-10-01

    The purpose of this study was to investigate in vitro release property of mono-PEGylated growth hormone-releasing peptide-6 (GHRP-6) microspheres. The microspheres encapsulating native GHRP-6 or mono-PEG-GHRP-6 were prepared using the single oil-in-water emulsion solvent evaporation method. In vitro release study was performed in 0.1M phosphate buffer, pH 7.4, containing 0.02% Tween 80 and sodium azide at 37 or 55 degrees C. The mono-PEG-GHRP-6 microspheres showed a lower initial burst compared with native GHRP-6 microspheres and zero-order release profile for a 1-month period. The release period was dependent on the PEG size attached to the GHRP-6 with more rapid drug release being observed with the smaller PEG size. This study suggests that PEGylated peptide has good potential as a source for a sustained release microsphere delivery system.

  16. Microsphere-integrated drug-eluting stents: PLGA microsphere integration in hydrogel coating for local and prolonged delivery of hydrophilic antirestenosis agents.

    PubMed

    Indolfi, Laura; Causa, Filippo; Giovino, Concetta; Ungaro, Francesca; Quaglia, Fabiana; Netti, Paolo Antonio

    2011-05-01

    The development of a novel generation of drug-eluting stent (DES) relies upon the idea to obtain very flexible platforms able to overcome some issues associated to available devices and widen their field of application, especially to the currently emerging biotech therapeutics. Here, we propose a new concept of DES named microsphere-integrated drug-eluting stent (MIDES) composed of drug eluting biodegradable poly(D,L-lactide-co-glycolide) microspheres--encapsulating an hydrophilic model molecule (dextran)--fully integrated in a poly(2-hydroxy-ethyl-methacrylate) coating. By implementing a modified spray-coating technique, we have been able to achieve a thin (10 μm), smooth, and homogeneous hydrogel surface embedding underneath a population of two different microparticles formulations--Dex502H and Dex506. The amount of drug can be tailored, resulting in a dextran loading as high as 1.4 μg/cm, by simply reiteration of coating layer deposition making the MIDES a custom-made device where the release kinetics can be further modified by opportunely choosing microsphere properties. DES use is nowadays restricted to delivery of hydrophobic pharmaceuticals; release of hydrophilic therapeutics from MIDES can, however, be finely controlled by specifically engineering biodegradable microspheres. By varying polymer resomer, we obtained a tunable release rate in the first month of delivery. Depending on the microspheres properties release profile changes drastically moving from a biphasic release, in the case of Dex502H, with a burst of about 20% in the first day to a more sustained release for Dex506 particles. As proof of principle, we also demonstrated that MIDES approach can allows the delivery of two different agents opening up the way to a multitherapy in restenosis treatment.

  17. Chitosan/nHAC/PLGA microsphere vehicle for sustained release of rhBMP-2 and its derived synthetic oligopeptide for bone regeneration.

    PubMed

    Ji, Yanhui; Wang, Mingbo; Liu, Weiqiang; Chen, Changsheng; Cui, Wei; Sun, Tingfang; Feng, Qingling; Guo, Xiaodong

    2016-11-10

    Both of the osteogenic factor and the suitable delivery system in bone tissue engineering are essential for bone regeneration. In this study, we manufactured two kinds of composite vehicles for sustained release of rhBMP-2 and its derived synthetic oligopeptide (Peptide-24, abbreviated as P24) for osteogenesis and bone defect repair. The composite vehicle was based on cross-linked chitosan, nano-hydroxyapatite/collagen (nHAC), and poly (lactide-co-glycolide) acid microsphere. The physicochemical properties of the composite vehicles (abbreviated as CS/nHAC/PLGA-MS) were investigated. The rhBMP-2 and P24 release kinetics from the vehicles were examined and the secondary structure of rhBMP-2 and P24 after 28 days' release process was analyzed. In vitro cell proliferation, osteogenic differentiation and rat calvarial defect repair were evaluated. The results proved that the composite vehicle had favorable compressive strength, elastic modulus, the porosity, and the bulk density. The secondary structures of rhBMP-2 and P24 kept stability during microencapsulation and release process. P24 from the vehicle kept a geared-up release and rhBMP-2 from the vehicle kept a three-stage mode release process. The results of in vitro cell detection showed that the composite vehicle had good biocompatibility and osteoinduction. In vivo rat calvarial defect repair demonstrated that both groups of vehicles with rhBMP2 and P24 exhibited satisfied bone defect repair. This research showed that the composite vehicle could exhibit sustained release of osteogenic factors. CS/nHAC/PLGA-MS loading rhBMP-2 or P24 could be a novel and ideal scaffold for bone regeneration. This article is protected by copyright. All rights reserved.

  18. Long-acting progestogens.

    PubMed

    Affandi, Biran

    2002-04-01

    Steroids can be administered in at least five different ways: injectables; hormone-releasing intra-uterine devices (IUDs); implants; vaginal rings; and pills. Progestogens which are synthetic steroids, are used as the main bioactive substances. Different progestogens are effective for different periods of time. Progestins in daily oral pills are effective for 24 hours. The effectiveness of a progestogen can be prolonged by incorporating it in a sustained-release system that gradually releases the hormone; therefore they can be effective up to 5 years or more. Two progestogen-only injectables are widely available in the family planning programmes, (DMPA and NET-EN) and two combined injectables, Cyclofem (DMPA + EC), and Mesigyna (NET-EN + EV). The ring is placed by the woman in her vagina, where it gradually releases hormone. Implantable contraceptives are placed just under the skin on the inside of the woman's arm. Implant capsules release the progestogen at a slow, steady rate. There are three implantables available in the market: Implanon; Norplant; and Jadelle. They are effective for 1-5 years, but then must be replaced. Natural and synthetic progestogens were first added to IUDs in the early 1970s. The main problem of long-acting progestogens is the disruption of the menstrual cycle.

  19. PLGA-PEG-PLGA microspheres as a delivery vehicle for antisense oligonucleotides to CTGF: Implications on post-surgical peritoneal adhesion prevention

    NASA Astrophysics Data System (ADS)

    Azeke, John Imuetinyan-Jesu, Jr.

    , while both cytokines are over-expressed within the first day following injury, CTGF protein levels could not be correlated with observed adhesion development. In addition, we synthesized linear triblock copolymers of polyethylene glycol (PEG) and poly(D,L-lactide-co-glycolide) (PLGA), two of the most widely studied biodegradable polymers in use today. Bulk gels and microparticles of the copolymers were then evaluated for gelling behavior, temperature stability, and drug loading and release kinetics in order assess their suitability as potential carriers of antisense therapeutics. A novel approach to affecting the antisense oligonucleotide release kinetics by varying the relative concentrations of co-encapsulated cationic lipid transfection agents was also presented.

  20. Microspheres

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Vital information on a person's physical condition can be obtained by identifying and counting the population of T-cells and B-cells, lymphocytes of the same shape and size that help the immune system protect the body from the invasion of disease. The late Dr. Alan Rembaum developed a method for identifying the cells. The method involved tagging the T-cells and B-cells with microspheres of different fluorescent color. Microspheres, which have fluorescent dye embedded in them, are chemically treated so that they can link with antibodies. With the help of a complex antibody/antigen reaction, the microspheres bind themselves to specific 'targets,' in this case the T-cells or B-cells. Each group of cells can then be analyzed by a photoelectronic instrument at different wavelengths emitted by the fluorescent dyes. Same concept was applied to the separation of cancer cells from normal cells. Microspheres were also used to conduct many other research projects. Under a patent license Magsphere, Inc. is producing a wide spectrum of microspheres on a large scale and selling them worldwide for various applications.

  1. Physicochemical and mechanical properties of freeze cast hydroxyapatite-gelatin scaffolds with dexamethasone loaded PLGA microspheres for hard tissue engineering applications.

    PubMed

    Ghorbani, Farnaz; Nojehdehian, Hanieh; Zamanian, Ali

    2016-12-01

    Hydroxyapatite (HA)-gelatin scaffolds incorporated with dexamethasone-loaded polylactic-co-glycolic acid (PLGA) microspheres were synthesized by freeze casting technique. Scanning electron microscopy (SEM) micrographs demonstrated a unidirectional microstructure and a decrease in the pore size as a function of temperature gradient. Higher amounts of HA resulted in a decrease in the pore size. According to the results, at lower cooling rates, the formation of a lamellar structure decreased the mechanical strength, but at the same time, enhanced the swelling ratio, biodegradation rate and drug release level. On the other hand, higher weight ratios of HA increased the compressive strength, and reduced the swelling ratio, biodegradation rate and drug release level. The results obtained by furrier transform infrared spectroscopy (FTIR) and bioactivity analysis illustrated that the interactions of the materials support the apatite formation in the simulated body fluid (SBF) solution. Based on the obtained results, the synthesized composite scaffolds have the necessary mechanical and physicochemical features to support the regeneration of defects and to maintain their stability during the neo-tissue formation.

  2. In vitro study of lysozyme in poly(lactide-co-glycolide) microspheres with sucrose acetate isobutyrate.

    PubMed

    Lee, Eun Seong; Kwon, Min Jung; Lee, Hyeok; Na, Kun; Kim, Jung Ju

    2006-12-01

    This study investigated the suitability of microsphere formulations for extended protein delivery and complete protein release. These microspheres were prepared by a multi-emulsion method and prepared using a mixture of poly(lactide-co-glycolide) (PLGA), RG 502H (lactide:glycolide=50:50, M(W) 9300) and sucrose acetate isobutyrate (SAIB). SAIB embedded into the microspheres and mixed with PLGA, improved the efficiency of enzyme encapsulation. The in vitro release rate of lysozyme (Lys) from the microspheres was reduced due to the high viscosity of the added SAIB and less degradation of PLGA by SAIB. These properties enabled prolonged release of Lys for up to 2 months, characterized by a minimal initial burst of Lys and nearly zero-order protein release kinetics result from co-administration of sorbitan monooleate 80. When it is considered that degradation products of SAIB are inactive for labile proteins, SAIB may be regarded as a promising candidate for long-acting protein delivery.

  3. Influence of PEI as a Core Modifying Agent on PLGA Microspheres of PGE1, A Pulmonary Selective Vasodilator

    PubMed Central

    Gupta, Vivek; Ahsan, Fakhrul

    2011-01-01

    This study tests the hypothesis that large porous poly (lactic-co-glycolic acid) (PLGA) microparticles modified with polyethyleneimine (PEI) are viable carriers for pulmonary delivery of prostaglandin E1 (PGE1) used in the treatment of pulmonary arterial hypertension (PAH), a pulmonary vascular disorder. The particles were prepared by a double-emulsion solvent evaporation method with PEI-25 kDa in the internal aqueous phase to produce an osmotic pressure gradient. Polyvinyl alcohol (PVA) was used for external coating of the particles. The particles were examined for morphology, size, aerodynamic diameter, surface area, pore volume and in-vitro release profiles. Particles with optimal properties for inhalation were tested for in-vivo pulmonary absorption, metabolic stability in rat lung homogenates, and acute toxicity in rat bronchoalveolar lavage fluid and respiratory epithelial cells, Calu-3. The micromeritic data indicated that the PEI-modified particles of PGE1 are optimal for inhalation. Incorporation of PEI in the formulations resulted in an increased entrapment efficiency–83.26±3.04% for particles with 1% PVA and 95.48±0.46% for particles with 2% PVA. The amount of cumulative drug released into the simulated interstitial lung fluid was between 50.8±0.76% and 55.36±0.06%. A remarkable extension of the circulation half-life up to 6.0–6.5 hours was observed when the formulations were administered via the lungs. The metabolic stability and toxicity studies showed that the optimized formulations were stable at physiological conditions and relatively safe to the lungs and respiratory epithelium. Overall, this study demonstrates that large porous inhalable polymeric microparticles can be a feasible option for non-invasive and controlled release of PGE1 for treatment of PAH. PMID:21530623

  4. Mycobacterium hsp65 DNA entrapped into TDM-loaded PLGA microspheres induces protection in mice against Leishmania (Leishmania) major infection.

    PubMed

    Coelho, Eduardo Antonio Ferraz; Tavares, Carlos Alberto Pereira; Lima, Karla de Melo; Silva, Célio Lopes; Rodrigues, José Maciel; Fernandes, Ana Paula

    2006-05-01

    Heat shock proteins (HSPs) are highly conserved among different organisms. A mycobacterial HSP65 DNA vaccine was previously shown to have prophylactic and immunotherapeutic effects against Mycobacterium tuberculosis infection in mice. Here, BALB/c mice were immunized with mycobacterial DNA-hsp65 or with DNA-hsp65 and trehalose dymicolate (TDM), both carried by biodegradable microspheres (MHSP/TDM), and challenged with Leishmania (Leishmania) major. MHSP/TDM conferred protection against L. major infection, as indicated by a significant reduction of edema and parasite loads in infected tissues. Although high levels of interferon-gamma and low levels of interleukin (IL)-4 and IL-10 were detected in mice immunized with DNA-hsp65 or MHSP/TDM, only animals immunized with MHSP/TDM displayed a consistent Th1 immune response, i.e., significantly higher levels of anti-soluble Leishmania antigen (SLA) immunoglobulin G (IgG)2a and low anti-SLA IgG1 antibodies. These findings indicate that encapsulated MHSP/TDM is more immunogenic than naked hsp65 DNA, and has great potential to improve vaccine effectiveness against leishmaniasis and tuberculosis.

  5. Six month delivery of GDNF from PLGA/vitamin E biodegradable microspheres after intravitreal injection in rabbits.

    PubMed

    García-Caballero, Cristina; Prieto-Calvo, Esther; Checa-Casalengua, Patricia; García-Martín, Elena; Polo-Llorens, Vicente; García-Feijoo, Julián; Molina-Martínez, Irene Teresa; Bravo-Osuna, Irene; Herrero-Vanrell, Rocío

    2017-03-01

    Local long-term delivery of glial cell line derived neurotrophic factor (GDNF) from vitamin E/poly-lactic-co-glycolic acid microspheres (MSs) protects retinal ganglion cells in an animal model of glaucoma for up to 11weeks. However, the pharmacokinetics of GDNF after intravitreal injection of MSs is not known. We evaluated the GDNF levels after a single intravitreal injection of GDNF/VitE MSs. Biodegradable MSs were prepared by the solid-oil-in-water emulsion-solvent evaporation technique and characterized. Rabbits received a single intravitreal injection (50μL) of GDNF/VitE MSs (4%w/v; 24 right eyes; 74.85ng GDNF), blank MSs (4%w/v; 24 left eyes), and balanced salt solution (4 eyes). Two controls eyes received no injections. At 24h, 1, 4, 6, 8, 12, 18, and 24weeks after injection, the eyes were enucleated, and the intravitreal GDNF levels were quantified. Pharmacokinetic data were analysed according to non-compartmental model. Intraocular GDNF levels of 717.1±145.1pg/mL were observed at 24h for GDNF-loaded MSs, followed by a plateau (745.3±25.5pg/mL) until day 28. After that, a second plateau (17.4±3.7pg/mL) occurred from 8 to 24weeks post-injection, significantly higher than the basal levels. Eyes injected with GDNF/vitE and Blank-MSs did not show any abnormalities during the six-months follow up after administration. The single injection of GDNF/VitE MSs provided a sustained controlled release of the neurotrophic factor in a controlled fashion for up to six months.

  6. Long-acting injectable hormonal dosage forms for contraception.

    PubMed

    Wu, Linfeng; Janagam, Dileep R; Mandrell, Timothy D; Johnson, James R; Lowe, Tao L

    2015-07-01

    Although great efforts have been made to develop long-acting injectable hormonal contraceptives for more than four decades, few long-acting injectable contraceptives have reached the pharmaceutical market or even entered clinical trials. On the other hand, in clinical practice there is an urgent need for injectable long-acting reversible contraceptives which can provide contraceptive protection for more than 3 months after one single injection. Availability of such products will offer great flexibility to women and resolve certain continuation issues currently occurring in clinics. Herein, we reviewed the strategies exploited in the past to develop injectable hormonal contraceptive dosages including drug microcrystal suspensions, drug-loaded microsphere suspensions and in situ forming depot systems for long-term contraception and discussed the potential solutions for remaining issues met in the previous development.

  7. Long-acting reversible contraception.

    PubMed

    Peck, Susan A

    2013-10-01

    Although short-acting reversible hormonal contraceptives, such as oral contraceptives and the contraceptive patch and vaginal ring, remain the most commonly used contraceptive methods in the United States, they are also associated with the highest failure rates. Long-acting reversible contraception (LARC) methods, such as intrauterine devices and contraceptive implants, offer high continuation rates and very low failure rates, and are safe for use in most women. The provision of LARC methods to adolescent, young adult and nulliparous women is a relatively new concept that offers an innovative option for these populations.

  8. Long-acting contraceptive options.

    PubMed

    Kaunitz, A M

    1996-01-01

    Long-acting contraceptive methods are appropriate choices for women who prefer the convenience and high contraceptive efficacy of methods not requiring frequent compliance, and women for whom contraceptive doses of estrogen are either medically contraindicated or associated with persistent intolerable side effects. Annual pregnancy rates for the three methods described below are less than 1 per 100 woman-years. As currently formulated, levonorgestrel implants (Norplant) consist of six 34 x 2.4 mm soft plastic implants, each filled with 36 mg of crystalline levonorgestrel. Irregular and often persistent menstrual bleeding and spotting constitute the most important side effects experienced by and leading to method discontinuation in implant users. Implant removal is technically more difficult and time-consuming than insertion. Depot-medroxyprogesterone acetate (DMPA or Depo-Provera) is injected as an aqueous suspension of microcrystals. Intramuscular injection of 150 mg of DMPA results in more than 3 months of contraception. Irregular bleeding and spotting followed by amenorrhea, constitute the most importance side effects experienced by DMPA users. Because DMPA use can result in prolonged (but not permanent) infertility, DMPA is not an optimum contraceptive choice for women who may want to conceive in the next one or two years. The Copper T380A intrauterine device (IUD) provides reversible contraception for up to 10 years. IUDs act as contraceptives, not early abortafacients. Recent epidemiologic data indicate that long-term IUD use does not increase the occurrence of pelvic inflammatory disease. Heavier menstrual flow and cramps constitute the main side effects experienced by women using the copper IUD. Intrauterine device insertion and removal are accomplished during brief office-based procedures.

  9. Injectable long-acting in situ forming systems for Radix Ophiopogonis polysaccharide.

    PubMed

    Shi, XiaoLi; Lin, Xiao; Yao, ChunXia; Shen, Lan; Feng, Yi

    2015-01-01

    In the area of injectable long-acting formulations, the in situ forming system (ISFS) is an attractive alternative for its various superiorities. In this study, both hydrophilic and hydrophobic in situ forming systems, using Poloxamer and sucrose acetate isobutyrate (SAIB) or poly(D,L-lactide-co-glycolide) copolymer (PLGA) as carrier, respectively, were investigated for Radix Ophiopogonis polysaccharide (ROP), a natural anti-myocardial ischemic fructan. A reasonable and applicable range of formulations were selected from each carrier for in vivo study by investigating their rheological property. The results from in vivo evaluation show that relatively promising sustained behaviors were achieved by formulations 24% P407/10% P188, 40% PLGA30k/NMP, and 30% PLGA50k/NMP. Significant differences of drug release kinetics were observed between in situ thermally-induced Poloxamer-based hydrogels and in situ solvent exchange-induced hydrophobic PLGA depots. This suggests that different ISFS could be chosen to provide different application purpose for polysaccharide drugs. In the case of ROP, Poloxamer-based ISFS is promising for short-term acute therapies; however, PLGA-based ISFS might be promising for long-term precaution or/and cure of myocardial ischemia.

  10. Long-acting local anesthetics in dentistry.

    PubMed Central

    Sisk, A. L.

    1992-01-01

    Long-acting local anesthetics have proved to be effective for the suppression of both intraoperative and postoperative pain. They are useful for lengthy dental treatments and for prevention of severe pain following many types of surgical procedures. Although the currently available long-acting local anesthetics for dentistry have minimal side effects in the doses usually employed, there are potential problems. Bupivacaine, for example, can cause significant cardiac depressant and dysrhythmogenic responses. Etidocaine has less pronounced effects on the cardiovascular system, but its use may be associated with inadequate control of intraoperative bleeding. A new long-acting local anesthetic, ropivacaine, appears to offer advantages over either of the currently used long-acting agents. PMID:1308373

  11. Long-acting local anesthetics in dentistry.

    PubMed

    Sisk, A L

    1992-01-01

    Long-acting local anesthetics have proved to be effective for the suppression of both intraoperative and postoperative pain. They are useful for lengthy dental treatments and for prevention of severe pain following many types of surgical procedures. Although the currently available long-acting local anesthetics for dentistry have minimal side effects in the doses usually employed, there are potential problems. Bupivacaine, for example, can cause significant cardiac depressant and dysrhythmogenic responses. Etidocaine has less pronounced effects on the cardiovascular system, but its use may be associated with inadequate control of intraoperative bleeding. A new long-acting local anesthetic, ropivacaine, appears to offer advantages over either of the currently used long-acting agents.

  12. On-demand one-step synthesis of monodisperse functional polymeric microspheres with droplet microfluidics.

    PubMed

    Yu, Xu; Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2015-04-07

    A simple and robust method for one-step synthesis of monodisperse functional polymeric microspheres was established by generation of reversed microemulsion droplets in aqueous phase inside microfluidic chips and controlled evaporation of the organic solvent. Using this method, water-soluble nanomaterials can be easily encapsulated into biodegradable Poly(D,L-lactic-co-glycolic acid) (PLGA) to form functional microspheres. By controlling the flow rate of microemulsion phase, PLGA polymeric microspheres with narrow size distribution and diameters in the range of ∼50-100 μm were obtained. As a demonstration of the versatility of the approach, high-quality fluorescent CdTe:Zn(2+) quantum dots (QDs) of various emission spectra, superparamagnetic Fe3O4 nanoparticles, and water-soluble carbon nanotubes (CNTs) were used to synthesize fluorescent PLGA@QDs, magnetic PLGA@Fe3O4, and PLGA@CNTs polymeric microspheres, respectively. In order to show specific applications, the PLGA@Fe3O4 were modified with polydopamine (PDA), and then the silver nanoparticles grew on the surfaces of the PLGA@Fe3O4@PDA polymeric microspheres by reducting the Ag(+) to Ag(0). The as-prepared PLGA@Fe3O4@PDA-Ag microspheres showed a highly efficient catalytic reduction of the 4-nitrophenol, a highly toxic substance. The monodisperse uniform functional PLGA polymeric microspheres can potentially be critically important for multiple biomedical applications.

  13. Synthesis and Characterization of PLGA Shell Microcapsules Containing Aqueous Cores Prepared by Internal Phase Separation.

    PubMed

    Abulateefeh, Samer R; Alkilany, Alaaldin M

    2016-08-01

    The preparation of microcapsules consisting of poly(D,L-lactide-co-glycolide) (PLGA) polymer shell and aqueous core is a clear challenge and hence has been rarely addressed in literature. Herein, aqueous core-PLGA shell microcapsules have been prepared by internal phase separation from acetone-water in oil emulsion. The resulting microcapsules exhibited mean particle size of 1.1 ± 0.39 μm (PDI = 0.35) with spherical surface morphology and internal poly-nuclear core morphology as indicated by scanning electron microscopy (SEM). The incorporation of water molecules into PLGA microcapsules was confirmed by differential scanning calorimetry (DSC). Aqueous core-PLGA shell microcapsules and the corresponding conventional PLGA microspheres were prepared and loaded with risedronate sodium as a model drug. Interestingly, aqueous core-PLGA shell microcapsules illustrated 2.5-fold increase in drug encapsulation in comparison to the classical PLGA microspheres (i.e., 31.6 vs. 12.7%), while exhibiting sustained release behavior following diffusion-controlled Higuchi model. The reported method could be extrapolated to encapsulate other water soluble drugs and hydrophilic macromolecules into PLGA microcapsules, which should overcome various drawbacks correlated with conventional PLGA microspheres in terms of drug loading and release.

  14. Long-acting injectable formulations of antipsychotic drugs for the treatment of schizophrenia.

    PubMed

    Park, Eun Ji; Amatya, Sarmila; Kim, Myung Sun; Park, Jong Hoon; Seol, Eunyoung; Lee, Heeyong; Shin, Young-Hee; Na, Dong Hee

    2013-06-01

    Antipsychotic drugs have been used to treat patients with schizophrenia and other psychotic disorders. Long-acting injectable antipsychotic drugs are useful for improving medication compliance with a better therapeutic option to treat patients who lack insight or adhere poorly to oral medication. Several long-acting injectable antipsychotic drugs are clinically available. Haloperidol decanoate and fluphenazine decanoate are first-generation depot drugs, but the use of these medicines has declined since the advent of second-generation depot agents, such as long-acting risperidone, paliperidone palmitate, and olanzapine pamoate. The second-generation depot drugs are better tolerated and have fewer adverse neurological side effects. Long-acting injectable risperidone, the first depot formulation of an atypical antipsychotic drug, was prepared by encapsulating risperidone into biodegradable microspheres. Paliperidone palmitate is an aqueous suspension of nanocrystal molecules, and olanzapine pamoate is a microcrystalline salt of olanzapine and pamoic acid suspended in aqueous solution. This review summarizes the characteristics and recent research of formulations of each long-acting injectable antipsychotic drug.

  15. Preparation, characterization and in vitro release study of BSA-loaded double-walled glucose-poly(lactide-co-glycolide) microspheres.

    PubMed

    Ansary, Rezaul H; Rahman, Mokhlesur M; Awang, Mohamed B; Katas, Haliza; Hadi, Hazrina; Mohamed, Farahidah; Doolaanea, Abd Almonem; Kamaruzzaman, Yunus B

    2016-09-01

    The aim of this study was to prepare a model protein, bovine serum albumin (BSA) loaded double-walled microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA) and a moderate-degrading carboxyl-terminated PLGA polymers to reduce the initial burst release and to eliminate the lag phase from the release profile of PLGA microspheres. The double-walled microspheres were prepared using a modified water-in-oil-in-oil-in-water (w/o/o/w) method and single-polymer microspheres were prepared using a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The particle size, morphology, encapsulation efficiency, thermal properties, in vitro drug release and structural integrity of BSA were evaluated in this study. Double-walled microspheres prepared with Glu-PLGA and PLGA polymers with a mass ratio of 1:1 were non-porous, smooth-surfaced, and spherical in shape. A significant reduction of initial burst release was achieved for the double-walled microspheres compared to single-polymer microspheres. In addition, microspheres prepared using Glu-PLGA and PLGA polymers in a mass ratio of 1:1 exhibited continuous BSA release after the small initial burst without any lag phase. It can be concluded that the double-walled microspheres made of Glu-PLGA and PLGA polymers in a mass ratio of 1:1 can be a potential delivery system for pharmaceutical proteins.

  16. Long-Acting Reversible Contraception for Adolescents.

    PubMed

    Fontenot, Holly B; Fantasia, Heidi Collins

    2015-01-01

    In 2013 and 2014, the Centers for Disease Control and Prevention (CDC) publicized its recommendations for the use of long-acting reversible contraception (LARC) (including intrauterine devices and implants) as first-line, highly effective options for pregnancy prevention. The use of LARC by adolescents has had growing support by national health and women's health organizations. Ongoing research is beginning to uncover facilitators and barriers to LARC use in adolescents. The purpose of this column is to highlight two recent U.S.-based studies in which researchers examined perspectives related to and factors associated with LARC use in adolescent and young adult women.

  17. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  18. Long-acting steroid contraceptive technology.

    PubMed

    Grubb, G

    1991-01-01

    Long-acting steroid contraceptive technologies that have either been recently approved or are currently under study are reviewed and the status of contraceptive research in the US is noted. The benefits and drawbacks, as well as the duration and possible cost, of each method are discussed. Approved by the Food and Drug Administration on December 10, 1990, Norplant is reportedly the first new contraceptive technology available to women in the US since the 1960s. This implant delivery system, which lasts up to 5 years, is cheaper than the pill and nearly as effective as sterilization. Study is currently under way on other multiyear, nonbiodegradable and biodegradable implants. Although already used by 4 million women worldwide, the long-acting injectable Depo-Provera has yet to be approved for use in the US. 5 new types of injectables are being developed. Steroid-containing IUDs have been in the market for some time, and current research is attempting to increase their contraceptive life beyond 1 year. Contraceptive developers are also exploring transdermal delivery systems, vaginal rings, and buccal and sublingual delivery. It is considered misleading to call Norplant the first new contraceptive introduced since the pill. Over the past 20 years, virtually every contraceptive has been significantly improved, developments that have enhanced the contraceptive options of couples. Because new contraceptive technologies are increasingly complex, their development is much slower. Consequently, it is concluded that in the foreseeable future, the demand for more acceptable contraceptives will be met through improvements of currently available technologies.

  19. Long-acting steroidal contraception: an update.

    PubMed

    Bardin, C W

    1989-01-01

    Long-acting, injectable contraceptives first became available in the 1960s. It is currently estimated that almost 3.5 million women are now using depo-medroxyprogesterone acetate (DMPA); 800,000 are using norethindrone enanthate (NET-EN), and another few hundred thousand are using a variety of once-a-month injectables comprised of progestin plus estrogen. The advantages of injectable contraceptives are that they are highly effective, independent of coitus, easily administered, and they ensure regular contact with health services personnel. The last factor may be considered a disadvantage by some, since contact is more frequent than would be required for routine health services. The major disadvantage of the progestin-only formulations is disruption of normal menses, giving rise to unpredicted episodes of bleeding and spotting. With the once-a-month formulation, on the other hand, there are few discontinuations due to disruption of menses. For a long-acting method to be used longer than 6 months, it is desirable to choose an implant, since the method can be discontinued at will. The first implant system to be developed was Norplant, a set of six rubber capsules filled with levonorgestrel and implanted under the skin. The implant releases sufficient levels of medication to protect against pregnancy. For the first 5 years, the average failure rate was four or five per thousand users per year. The failure rate for women using standard oral contraceptives is approximately 20 to 50 per thousand. The most common side effect of the implant method is the disruption of the menstrual cycle, an effect that is particularly marked in the first month of use.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Drug release behavior of poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA) prepared by direct polycondensation.

    PubMed

    Shi, Gang; Ding, Yuanyuan; Zhang, Xin; Wu, Luyan; He, Fei; Ni, Caihua

    2015-01-01

    Hydrophobically modified sodium alginate, poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA), was successfully synthesized through direct one-step polymerization of sodium alginate, glycolic acid, and lactic acid. ALG-g-PLGA self-assembled to colloidal nanoparticles and subsequently hydrogel microspheres were obtained by crosslinking ALG-g-PLGA nanoparticles in the solution of calcium chloride. The modified hydrogel microspheres could be used as the drug delivery vehicles for a hydrophobic ibuprofen. Compared with sodium alginate, ALG-g-PLGA demonstrated an improved drug loading rate, encapsulation efficiency, and prolonged release speed. The products, as novel and highly promising biomaterials, have potential applications.

  1. Where next with long-acting steroids?

    PubMed

    Potts, D M; Siemens, A J

    1984-06-01

    developing countries. The system consists of biodegradable polymeric microspheres containing NET which are injected intramuscularly as a suspension. Depending on the size of the microspheres the product can provide 30,90, or 180 day contraceptive protect ive with a single dose. The availability of the 3 formulations each with different durations of action will serve the contraceptive needs of varied populations. Most longacting steroidal contraceptives give rise to menstrual irregularities, but they have the convenience of long action and the physiological advantage of low doses delivered directly to the systemic circulation. Use by millions of women for 1-2 decades will be required before they are completely understood.

  2. A novel strategy for the preparation of porous microspheres and its application in peptide drug loading.

    PubMed

    Wei, Yi; Wang, Yuxia; Zhang, Huixia; Zhou, Weiqing; Ma, Guanghui

    2016-09-15

    A new strategy is developed to prepare porous microspheres with narrow size distribution for peptides controlled release, involving a fabrication of porous microspheres without any porogens followed by a pore closing process. Amphiphilic polymers with different hydrophobic segments (poly(monomethoxypolyethylene glycol-co-d,l-lactide) (mPEG-PLA), poly(monomethoxypolyethylene glycol-co-d,l-lactic-co-glycolic acid) (mPEG-PLGA)) are employed as microspheres matrix to prepare porous microspheres based on a double emulsion-premix membrane emulsification technique combined with a solvent evaporation method. Both microspheres possess narrow size distribution and porous surface, which are mainly caused by (a) hydrophilic polyethylene glycol (PEG) segments absorbing water molecules followed by a water evaporation process and (b) local explosion of microspheres due to fast evaporation of dichloromethane (MC). Importantly, mPEG-PLGA microspheres have a honeycomb like structure while mPEG-PLA microspheres have a solid structure internally, illustrating that the different hydrophobic segments could modulate the affinity between solvent and matrix polymer and influence the phase separation rate of microspheres matrix. Long term release patterns are demonstrated with pore-closed microspheres, which are prepared from mPEG-PLGA microspheres loading salmon calcitonin (SCT). These results suggest that it is potential to construct porous microspheres for drug sustained release using permanent geometric templates as new porogens.

  3. A protein delivery system: biodegradable alginate-chitosan-poly(lactic-co-glycolic acid) composite microspheres.

    PubMed

    Zheng, Cai-Hong; Gao, Jian-Qing; Zhang, Ye-Ping; Liang, Wen-Quan

    2004-10-29

    In the present study we developed alginate-chitosan-poly(lactic-co-glycolic acid) (PLGA) composite microspheres to elevate protein entrapment efficiency and decrease its burst release. Bovine serum albumin (BSA), which used as the model protein, was entrapped into the alginate microcapsules by a modified emulsification method in an isopropyl alcohol-washed way. The rapid drug releases were sustained by chitosan coating. To obtain the desired release properties, the alginate-chitosan microcapsules were further incorporated in the PLGA to form the composite microspheres. The average diameter of the composite microcapsules was 31+/-9microm and the encapsulation efficiency was 81-87%, while that of conventional PLGA microspheres was just 61-65%. Furthermore, the burst releases at 1h of BSA entrapped in composite microspheres which containing PLGA (50:50) and PLGA (70:30) decreased to 24% and 8% in PBS, and further decreased to 5% and 2% in saline. On the contrary, the burst releases of conventional PLGA microspheres were 48% and 52% in PBS, respectively. Moreover, the release profiles could be manipulated by regulating the ratios of poly(lactic acid) to poly(glycolic acid) in the composite microspheres.

  4. Subcritical CO2 Sintering of Microspheres of Different Polymeric Materials to Fabricate Scaffolds for Tissue Engineering

    PubMed Central

    Bhamidipati, Manjari; Sridharan, BanuPriya; Scurto, Aaron M; Detamore, Michael S.

    2013-01-01

    The aim of this study was to use CO2 at sub-critical pressures as a tool to sinter 3D, macroporous, microsphere-based scaffolds for bone and cartilage Tissue Engineering Porous scaffolds composed of ~200 µm microspheres of either poly(lactic-co-glycolic acid) (PLGA) or polycaprolactone (PCL) were prepared using dense phase CO2 sintering, which were seeded with rat bone marrow mesenchymal stromal cells (rBMSCs), and exposed to either osteogenic (PLGA, PCL) or chondrogenic (PLGA) conditions for 6 weeks. Under osteogenic conditions, the PLGA constructs produced over an order of magnitude more calcium than the PCL constructs, whereas the PCL constructs had far superior mechanical and structural integrity (125 times stiffer than PLGA constructs) at week 6, along with twice the cell content of the PLGA constructs. Chondrogenic cell performance was limited in PLGA constructs, perhaps as a result of the polymer degradation rate being too high. The current study represents the first long-term culture of CO2-sintered microsphere-based scaffolds, and has established important thermodynamic differences in sintering between the selected formulations of PLGA and PCL, with the former requiring adjustment of pressure only, and the latter requiring the adjustment of both pressure and temperature. Based on more straightforward sintering conditions and more favorable cell performance, PLGA may be the material of choice for microspheres in a CO2 sintering application, although a different PLGA formulation with the encapsulation of growth factors, extracellular matrix-derived nanoparticles, and/or buffers in the microspheres may be advantageous for achieving a more superior cell performance than observed here. PMID:24094202

  5. Preparation and Analysis of Co-precipitated, Biodegradable Poly-(Lactide-co-Glycolide) and Polyethylene Glycol Microspheres Prepared by Spray Drying

    NASA Astrophysics Data System (ADS)

    Javiya, Curie

    Biodegradable poly-(d,l-lactide-co-glycolide) (PLGA) based microspheres are commonly used for numerous clinical applications. PEG is a widely used polymer due to its hydrophilic, biocompatible, and nontoxic nature. In this study, different blends of PLGA/PEG microspheres were prepared using a spray drying technique. The microspheres were spherical with maximum yield found to be 60.3% and average particle size in the range of 2.4 to 3.1 microm. Under the spray drying processing conditions, the polymers showed full miscibility slightly below 15% w/w and partial miscibility up to 20% w/w of PEG in the blended microspheres. At higher temperatures, PLGA and PEG were miscible in all proportions used for the blended microspheres. Blending 10% w/w PEG in PLGA membranes showed significant reduction in attachment of macrophages compared to PLGA membranes. The in-vitro response of macrophage towards the miscible blends of PLGA/PEG microspheres was further characterized. Results showed some reduction in macrophage viability and activation, however, significant effects with PLGA/PEG microspheres were not observed.

  6. Long-acting contraceptive agents: testosterone esters of unsaturated acids.

    PubMed

    Francisco, C G; Freire, R; Gawronski, J; Hernández, R; Kielczewski, M; Salazar, J A; Savabi, F; Shafiee, A; Strekowski, L; Suárez, E

    1990-01-01

    The synthesis of 13 new esters of testosterone is described, with the esterifying acids bearing acetylenic, olefinic, or polyunsaturated functions in the chain, for evaluation as long-acting androgens.

  7. Long-acting contraceptive agents: levonorgestrel esters of unsaturated acids.

    PubMed

    Wan, A S; Ngiam, T L; Leung, S L; Go, M L; Francisco, C G; Freire, R; Hernandez, R; Salazar, J A; Suarez, E; García, G A

    1983-03-01

    Esters of levonorgestrel (13 beta-ethyl-17 beta-ethynyl-17 beta-hydroxygon-4-en-3-one) with a variety of unsaturated carboxylic acids have been synthesized for evaluation as potential long-acting, injectable contraceptive agents.

  8. A Systemic Review and Experts' Consensus for Long-acting Injectable Antipsychotics in Bipolar Disorder.

    PubMed

    Chou, Yuan Hwa; Chu, Po-Chung; Wu, Szu-Wei; Lee, Jen-Chin; Lee, Yi-Hsuan; Sun, I-Wen; Chang, Chen-Lin; Huang, Chien-Liang; Liu, I-Chao; Tsai, Chia-Fen; Yen, Yung-Chieh

    2015-08-31

    Bipolar disorder (BD) is a major psychiatric disorder that is easily misdiagnosed. Patient adherence to a treatment regimen is of utmost importance for successful outcomes in BD. Several trials of antipsychotics suggested that depot antipsychotics, including long-acting first- and second-generation agents, are effective in preventing non-adherence, partial adherence, and in reducing relapse in BD. Various long-acting injectable (LAI) antipsychotics are available, including fluphenazine decanoate, haloperidol decanoate, olanzapine pamoate, risperidone microspheres, paliperidone palmitate, and aripiprazole monohydrate. Due to the increasing number of BD patients receiving LAI antipsychotics, treatment guidelines have been developed. However, the clinical applicability of LAI antipsychotics remains a global cause for concern, particularly in Asian countries. Expert physicians from Taiwan participated in a consensus meeting, which was held to review key areas based on both current literature and clinical practice. The purpose of this meeting was to generate a practical and implementable set of recommendations for LAI antipsychotic use to treat BD; target patient groups, dosage, administration, and adverse effects were considered. Experts recommended using LAI antipsychotics in patients with schizophrenia, rapid cycling BD, BD I, and bipolar-type schizoaffective disorder. LAI antipsychotic use was recommended in BD patients with the following characteristics: multiple episodes and low adherence; seldom yet serious episodes; low adherence potential per a physician's clinical judgment; preference for injectable agents over oral agents; and multiple oral agent users still experiencing residual symptoms.

  9. A Systemic Review and Experts’ Consensus for Long-acting Injectable Antipsychotics in Bipolar Disorder

    PubMed Central

    Chou, Yuan Hwa; Chu, Po-Chung; Wu, Szu-Wei; Lee, Jen-Chin; Lee, Yi-Hsuan; Sun, I-Wen; Chang, Chen-Lin; Huang, Chien-Liang; Liu, I-Chao; Tsai, Chia-Fen; Yen, Yung-Chieh

    2015-01-01

    Bipolar disorder (BD) is a major psychiatric disorder that is easily misdiagnosed. Patient adherence to a treatment regimen is of utmost importance for successful outcomes in BD. Several trials of antipsychotics suggested that depot antipsychotics, including long-acting first- and second-generation agents, are effective in preventing non-adherence, partial adherence, and in reducing relapse in BD. Various long-acting injectable (LAI) antipsychotics are available, including fluphenazine decanoate, haloperidol decanoate, olanzapine pamoate, risperidone microspheres, paliperidone palmitate, and aripiprazole monohydrate. Due to the increasing number of BD patients receiving LAI antipsychotics, treatment guidelines have been developed. However, the clinical applicability of LAI antipsychotics remains a global cause for concern, particularly in Asian countries. Expert physicians from Taiwan participated in a consensus meeting, which was held to review key areas based on both current literature and clinical practice. The purpose of this meeting was to generate a practical and implementable set of recommendations for LAI antipsychotic use to treat BD; target patient groups, dosage, administration, and adverse effects were considered. Experts recommended using LAI antipsychotics in patients with schizophrenia, rapid cycling BD, BD I, and bipolar-type schizoaffective disorder. LAI antipsychotic use was recommended in BD patients with the following characteristics: multiple episodes and low adherence; seldom yet serious episodes; low adherence potential per a physician’s clinical judgment; preference for injectable agents over oral agents; and multiple oral agent users still experiencing residual symptoms. PMID:26243837

  10. Drug-loaded biodegradable microspheres for image-guided combinatory epigenetic therapy in cells

    NASA Astrophysics Data System (ADS)

    Xu, Ronald X.; Xu, Jeff S.; Zuo, Tao; Shen, Rulong; Huang, Tim H.; Tweedle, Michael F.

    2011-02-01

    We synthesize drug-loaded poly (lactic-co-glycolic acid) (PLGA) microspheres for image-guided combinatory epigenetic therapy in MCF-10A human mammary epithelial cells. LY294002 and Nile Red are encapsulated in microspheres for sustained drug release and fluorescence microscopic imaging. Drug-loaded microspheres target MCF-10A cells through a three-step binding process involving biotinylated antibody, streptavidin, and biotinylated microspheres. LY294002 loaded microspheres and 5-Aza-2-deoxycytidine are applied to MCF-10A cells for combinatory PI3K/AKT inhibition and deoxyribonucleic acid (DNA) demethylation. Our study implies the technical potential of disease targeting and image-guided combinatory epigenetic therapy using drug-loaded multifunctional biodegradable PLGA microspheres.

  11. Long-acting injectable aripiprazole: how might it fit in our tool box?

    PubMed

    Gopalakrishna, Ganesh; Aggarwal, Arpit; Lauriello, John

    2013-01-01

    Schizophrenia is a severe mental illness with a lifetime prevalence of approximately one percent worldwide. Maintenance antipsychotic treatment has been effective in preventing relapses in long-term follow-up studies. Logically it can be proposed that long-acting injectable antipsychotics (LAI) might reduce both unintentional and intentional nonadherence. Long-acting injectable aripiprazole was approved for the treatment of schizophrenia by the U.S. FDA on 28th February 2013 and will be marketed under the name Abilify Maintena. Aripiprazole LAI (ALAI) is a lyophilized powder that needs to be reconstituted with sterile water to form an injectable suspension without affecting the original molecule. The monthly injection interval is very attractive since patients prefer fewer injections. From a tolerability perspective, ALAI appears to be both weight neutral and lacking metabolic side effects. This can confer an advantage over the other currently available second-generation antipsychotic LAIs. Simple constitution with sterile water and no requirement to refrigerate make storage and administration easier. Like all medications, there are always potential disadvantages to ALAI. There is a period of oral coverage, while not as long as for long-acting risperidone microspheres (RLAI), that is required. Care must be taken to review concomitant medications for the presence of metabolic inducers and inhibitors. One would also expect some patients to be sensitive to extrapyramidal symptoms, especially akathisia which is well documented in the oral preparation. All things considered, we welcome our new tool, ALAI, to our work-place and predict both clinical practice and post marketing analysis and studies will discover its true value.

  12. Long-acting injectable antiretrovirals for HIV treatment and prevention

    PubMed Central

    Spreen, William R.; Margolis, David A.; Pottage, John C.

    2013-01-01

    Purpose of review Long-acting antiretroviral (ARV) drugs may improve adherence to therapy and extend opportunities for therapeutic or prophylactic intervention to underserved patient populations. This review focuses on recent advances in the development of small molecule long-acting injectable ARV agents. Recent findings The need for combination ART and physicochemical and dosing limitations of current ARV drugs impede attempts to redevelop them as long-acting injectable formulations. However, the intrinsic properties of rilpivirine, a nonnucleoside reverse transcriptase inhibitor, and GSK1265744, an HIV-1 integrase strand transfer inhibitor, have enabled crystalline nanoparticle formulations to progress to clinical trials. Summary Investigational long-acting injectable nanoformulations of rilpivirine and GSK1265744 are clinical-stage development candidates. Complementary pharmacologic properties of both agents – different mechanisms of action, resistance profiles, metabolic pathways, lack of drug interactions and low daily oral doses – offer the potential for combination use. Phase I studies of the pharmacokinetics and safety of each long-acting formulation alone and in combination indicate that a monthly dosing regimen is possible for HIV treatment. An ongoing phase IIb trial of oral GSK1265744 and oral rilpivirine is evaluating this two-drug regimen for maintenance of virologic suppression; results will inform future studies using the injectable formulations. Additional preclinical and clinical studies indicate a potential use of each agent for HIV pre-exposure prophylaxis. PMID:24100877

  13. Clinical blood chemistry values and long acting phenothiazines.

    PubMed

    Schneider, S J; Kirby, E J; Itil, T M

    1981-05-01

    Fifty-nine chronic schizophrenic patients received one year of treatment with either fluphenazine enanthate or pipothiazine palmitate IM. Both long acting neuroleptics significantly decreased serum albumin, total protein and creatinine values. Triglycerides were decreased only early in treatment. Pretreatment findings from therapy responders, as compared with those who failed to respond to treatment, included higher albumin values and to a lesser extent, lower lactic dehydrogenase values and greater height. These results were discussed with an eye toward the hepatocellular effects of long acting phenothiazines and the effect of liver function on the pharmacokinetics of these medications.

  14. Poly(ethylene glycol)-poly(lactic-co-glycolic acid) core-shell microspheres with enhanced controllability of drug encapsulation and release rate.

    PubMed

    Cha, Chaenyung; Jeong, Jae Hyun; Kong, Hyunjoon

    2015-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres have been widely used as drug carriers for minimally invasive, local, and sustained drug delivery. However, their use is often plagued by limited controllability of encapsulation efficiency, initial burst, and release rate of drug molecules, which cause unsatisfactory outcomes and several side effects including inflammation. This study presents a new strategy of tuning the encapsulation efficiency and the release rate of protein drugs from a PLGA microsphere by filling the hollow core of the microsphere with poly(ethylene glycol) (PEG) hydrogels of varying cross-linking density. The PEG gel cores were prepared by inducing in situ cross-linking reactions of PEG monoacrylate solution within the PLGA microspheres. The resulting PEG-PLGA core-shell microspheres exhibited (1) increased encapsulation efficiency, (2) decreased initial burst, and (3) a more sustained release of protein drugs, as the cross-linking density of the PEG gel core was increased. In addition, implantation of PEG-PLGA core-shell microspheres encapsulated with vascular endothelial growth factor (VEGF) onto a chicken chorioallantoic membrane resulted in a significant increase in the number of new blood vessels at an implantation site, while minimizing inflammation. Overall, this strategy of introducing PEG gel into PLGA microspheres will be highly useful in tuning release rates and ultimately in improving the therapeutic efficacy of a wide array of protein drugs.

  15. Exendin-4-loaded PLGA microspheres relieve cerebral ischemia/reperfusion injury and neurologic deficits through long-lasting bioactivity-mediated phosphorylated Akt/eNOS signaling in rats

    PubMed Central

    Chien, Chiang-Ting; Jou, Ming-Jia; Cheng, Tai-Yu; Yang, Chih-Hui; Yu, Tzu-Ying; Li, Ping-Chia

    2015-01-01

    Glucagon-like peptide-1 (GLP-1) receptor activation in the brain provides neuroprotection. Exendin-4 (Ex-4), a GLP-1 analog, has seen limited clinical usage because of its short half-life. We developed long-lasting Ex-4-loaded poly(D,L-lactide-co-glycolide) microspheres (PEx-4) and explored its neuroprotective potential against cerebral ischemia in diabetic rats. Compared with Ex-4, PEx-4 in the gradually degraded microspheres sustained higher Ex-4 levels in the plasma and cerebrospinal fluid for at least 2 weeks and improved diabetes-induced glycemia after a single subcutaneous administration (20 μg/day). Ten minutes of bilateral carotid artery occlusion (CAO) combined with hemorrhage-induced hypotension (around 30 mm Hg) significantly decreased cerebral blood flow and microcirculation in male Wistar rats subjected to streptozotocin-induced diabetes. CAO increased cortical O2− levels by chemiluminescence amplification and prefrontal cortex edema by T2-weighted magnetic resonance imaging analysis. CAO significantly increased aquaporin 4 and glial fibrillary acidic protein expression and led to cognition deficits. CAO downregulated phosphorylated Akt/endothelial nitric oxide synthase (p-Akt/p-eNOS) signaling and enhanced nuclear factor (NF)-κBp65/intercellular adhesion molecule-1 (ICAM-1) expression, endoplasmic reticulum (ER) stress, and apoptosis in the cerebral cortex. PEx-4 was more effective than Ex-4 to improve CAO-induced oxidative injury and cognitive deficits. The neuroprotection provided by PEx-4 was through p-Akt/p-eNOS pathways, which suppressed CAO-enhanced NF-κB/ICAM-1 signaling, ER stress, and apoptosis. PMID:26058696

  16. Biodegradable polymer-silica xerogel composite microspheres for controlled release of gentamicin.

    PubMed

    Xue, J M; Tan, C H; Lukito, D

    2006-08-01

    Single and double layered composite microspheres were prepared by encapsulating gentamicin-loaded silica xerogels with biodegradable PLGA polymers (poly(DL-lactide-co-glycolide)). The in vitro drug release properties of both the composite microspheres were investigated. The single layered composite microspheres showed a high initial burst, followed by two sustained release stages lasting for approximately 6 weeks. The two sustained release stages of the single layered composite microspheres could be attributed to the swelling and bulk erosion of the polymer encapsulations, respectively. In comparison with the single layered composite microspheres, the double layered composite microspheres realized a much reduced initial burst together with three sustained release stages. The whole release period of the double layered composite microspheres could last more than 9 weeks. These distinct behaviors make the double layered composite microspheres promising as a new drug release material for localized drug delivery applications.

  17. Nanoscaled buffering zone of charged (PLGA)n-b-bPEI micelles in acidic microclimate for potential protein delivery application

    PubMed Central

    Kang, Han Chang; Lee, Ji Eun; Bae, You Han

    2012-01-01

    Poly(lactide-co-glycolide) (PLGA) has most often been employed for the controlled release of protein formulations because of its safety profile with non-toxic degradation products. Nevertheless, such formulations have been plagued by a local acidic microenvironment and protein-polymer interactions, which result in chemical and physical denaturation of loaded proteins and often unfavorable release profiles. This study investigated the pH change of inner PLGA microsphere (MS) using charged (PLGA)n-b-branched polyethyleneimine (bPEI) micelles. The designed micelles can be transformed into either micelle or reverse micelle (RM) depending on the solvent and RM can form microspheres. In addition, (PLGA)n-b-bPEI can be modified into (PLGA)n-b-(carboxylated bPEI) via carboxylation of the primary amines. Cationic micelle (CM) or anionic micelle (AM) were complexed with counter-charged proteins leading to nanosized particles (approximately 100 nm). In the micelle/protein complexes, the micelles mostly maintained their proton buffering capacity, and consequently, prevented or delayed the typical decrease in pH caused by degradation of PLGA in aqueous solution. Reconstitutable micelle/protein complexes allowed for increased and fine-tuned protein loading (~20 wt% when using CM1 (CM prepared from PLGA36kDa-b-bPEI25kDa)/insulin complexes) in PLGA MS. In CM2 (CM prepared from (PLGA36kDa)2-b-bPEI25kDa)/insulin (4 of weight ratio (WR) of micelle to protein; WR4)-loaded PLGA MS, CM2 strongly prevented the micellar nanoenvironmental pH (pH 6.6 within 5 days and then approximately pH 8.5) to be acidified in PLGA MS for 9 weeks, unlike CM2-free PLGA MS. In conclusion, our findings propose that the proton buffering capacity and protein loading in PLGA MS can be tuned by controlling the complexation ratios of micelles and proteins, polymeric architectures of (PLGA)n-b-bPEI copolymers and WR of micelle/protein complexes and PLGA (or RM). PMID:22405902

  18. Long-acting reversible contraceptives for teenagers: primary care recommendations.

    PubMed

    Atkin, Kathryn; Beal, Margaret W; Long-Middleton, Ellen; Roncari, Danielle

    2015-03-12

    Long-acting reversible contraceptive (LARC) methods are underutilized in the adolescent population despite their superior efficacy over non-LARC methods. The purpose of this article is to discuss the barriers that lead to underutilization of these methods and present an evidence-based approach for the use of LARC methods among adolescents in the primary care setting.

  19. Long-acting contraceptive agents: norethisterone esters of polyunsaturated acids.

    PubMed

    Francisco, C G; Freire, R; Hernandez, R; Salazar, J A; Suarez, E; Vlahov, R; Tarpanov, V; Boshkova-Ljapova, M; Milenkov, B; Stoilova, V

    1983-03-01

    Some new derivatives of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) are described in which the 17 beta-hydroxyl group of the steroid is esterified with polyunsaturated aliphatic acids. The potential of these compounds as long-acting contraceptive agents has been evaluated.

  20. Safety evaluation of poly(lactic-co-glycolic acid)/poly(lactic-acid) microspheres through intravitreal injection in rabbits.

    PubMed

    Rong, Xianfang; Yuan, Weien; Lu, Yi; Mo, Xiaofen

    2014-01-01

    Poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic-acid) (PLA) microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of PLGA/PLA microspheres through intravitreal injection in rabbits. Normal New Zealand rabbits were randomly selected and received intravitreal administration of different doses (low, medium, or high) of PLGA/PLA microspheres and erythropoietin-loaded PLGA/PLA microspheres. The animals were clinically examined and sacrificed at 1, 2, 4, 8, and 12 weeks postadministration, and retinal tissues were prepared for analysis. Retinal reactions to the microspheres were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end staining and glial fibrillary acidic protein immunohistochemistry. Retinal structure changes were assessed by hematoxylin and eosin staining and transmission electron microscopy. Finally, retinal function influences were explored by the electroretinography test. Terminal deoxynucleotidyl transferase-mediated dUTP nick end staining revealed no apoptotic cells in the injected retinas; immunohistochemistry did not detect any increased glial fibrillary acidic protein expression. Hematoxylin and eosin staining and transmission electron microscopy revealed no micro- or ultrastructure changes in the retinas at different time points postintravitreal injection. The electroretinography test showed no significant influence of scotopic or photopic amplitudes. The results demonstrated that PLGA/PLA microspheres did not cause retinal histological changes or functional damage and were biocompatible and safe enough for intravitreal injection in rabbits for controlled drug delivery.

  1. Two cases of long-acting paliperidone in adolescence

    PubMed Central

    Fàbrega, Marina; Sugranyes, Gisela; Baeza, Inmaculada

    2015-01-01

    Paliperidone palmitate long-acting injection (PPLAI) is an atypical antipsychotic agent currently approved by the European Medicine Agency for the acute and maintenance treatment of schizophrenia in adults. However, there is no information so far on safety and effectiveness in patients under 18 years of age. We report on two clinical cases of adolescents with a psychotic spectrum disorder treated with PPLAI in an inpatient setting. The cases illustrate that PPLAI may hold potential as an effective and acceptably tolerated antipsychotic drug in adolescents with psychotic spectrum disorders. Given the lack of approved long acting injectable antipsychotics in patients under 18 years of age, reports on the effectiveness and safety of such medications in children and adolescent patients are of importance. PMID:26557986

  2. Status of long-acting-growth hormone preparations--2015.

    PubMed

    Høybye, Charlotte; Cohen, Pinchas; Hoffman, Andrew R; Ross, Richard; Biller, Beverly M K; Christiansen, Jens Sandahl

    2015-10-01

    Growth hormone (GH) treatment has been an established therapy for GH deficiency (GHD) in children and adults for more than three decades. Numerous studies have shown that GH treatment improves height, body composition, bone density, cardiovascular risk factors, physical fitness and quality of life and that the treatment has few side effects. Initially GH was given as intramuscular injections three times per week, but daily subcutaneous injections were shown to be more effective and less inconvenient and the daily administration has been used since its introduction in the 1980s. However, despite ongoing improvements in injection device design, daily subcutaneous injections remain inconvenient, painful and distressing for many patients, leading to noncompliance, reduced efficacy and increased health care costs. To address these issues a variety of long-acting formulations of GH have been developed. In this review we present the current status of long-acting GH preparations and discuss the specific issues related to their development.

  3. Three-dimensional study of poly(lactic co-glycolic acid) micro-porous microspheres using hard X-ray nano-tomography.

    PubMed

    Wang, Dajiang; Li, Na; Wang, Zhili; Gao, Kun; Zhang, Yongming; Luo, Yuyan; Wang, Shengxiang; Bao, Yuan; Shao, Qigang; Wu, Ziyu

    2014-09-01

    Poly(lactic co-glycolic acid) (PLGA) is widely used in diverse fields, especially in delivering biologically active proteins and drugs. For these applications, the knowledge of morphology and microstructure of PLGA micro-porous microspheres is of great importance since they strongly influence the drug delivering efficiency. In this study, micro-porous PLGA microspheres loaded by bovine serum albumin are investigated by using a full-field Zernike phase contrast transmission hard X-ray microscope. From three-dimensional reconstructions and segmentations, fundamental microstructural parameters such as size, shape, distribution and volume ratio among pores and proteins inside PLGA microspheres were obtained. These parameters are useful to understand the relationship between the internal microstructure and drug encapsulation, as well as the drug release efficiency of PLGA microspheres. The presented results demonstrate the capability of hard X-ray nano-tomography to characterize porous microspheres loaded with proteins and drugs, and also open a way to analyse, optimize and design new PLGA microspheres for specific applications.

  4. Controlled drug release from a novel injectable biodegradable microsphere/scaffold composite based on poly(propylene fumarate).

    PubMed

    Kempen, Diederik H R; Lu, Lichun; Kim, Choll; Zhu, Xun; Dhert, Wouter J A; Currier, Bradford L; Yaszemski, Michael J

    2006-04-01

    The ideal biomaterial for the repair of bone defects is expected to have good mechanical properties, be fabricated easily into a desired shape, support cell attachment, allow controlled release of bioactive factors to induce bone formation, and biodegrade into nontoxic products to permit natural bone formation and remodeling. The synthetic polymer poly(propylene fumarate) (PPF) holds great promise as such a biomaterial. In previous work we developed poly(DL-lactic-co-glycolic acid) (PLGA) and PPF microspheres for the controlled delivery of bioactive molecules. This study presents an approach to incorporate these microspheres into an injectable, porous PPF scaffold. Model drug Texas red dextran (TRD) was encapsulated into biodegradable PLGA and PPF microspheres at 2 microg/mg microsphere. Five porous composite formulations were fabricated via a gas foaming technique by combining the injectable PPF paste with the PLGA or PPF microspheres at 100 or 250 mg microsphere per composite formulation, or a control aqueous TRD solution (200 microg per composite). All scaffolds had an interconnected pore network with an average porosity of 64.8 +/- 3.6%. The presence of microspheres in the composite scaffolds was confirmed by scanning electron microscopy and confocal microscopy. The composite scaffolds exhibited a sustained release of the model drug for at least 28 days and had minimal burst release during the initial phase of release, as compared to drug release from microspheres alone. The compressive moduli of the scaffolds were between 2.4 and 26.2 MPa after fabrication, and between 14.9 and 62.8 MPa after 28 days in PBS. The scaffolds containing PPF microspheres exhibited a significantly higher initial compressive modulus than those containing PLGA microspheres. Increasing the amount of microspheres in the composites was found to significantly decrease the initial compressive modulus. The novel injectable PPF-based microsphere/scaffold composites developed in this study

  5. Pharmacokinetics and tolerability of long-acting risperidone in schizophrenia.

    PubMed

    Eerdekens, Mariëlle; Van Hove, Ilse; Remmerie, Bart; Mannaert, Erik

    2004-09-01

    The pharmacokinetics and tolerability of long-acting risperidone (Risperdal Consta) were evaluated in a multicenter, prospective, open-label, 15-week study of 86 patients with schizophrenia. Subjects stabilized on 2, 4 or 6 mg of oral risperidone once daily for at least 4 weeks were assigned to receive i.m. injections of 25, 50 or 75 mg of risperidone, respectively, every 2 weeks for 10 weeks. The 90% confidence intervals for the i.m./oral ratios of the mean steady-state plasma-AUC, corrected for dosing interval, and of the average plasma concentration of the active moiety (risperidone plus 9-hydroxyrisperidone) were within the range of 80-125%, indicating bioequivalence of the i.m. and oral formulations. However, mean steady-state peak concentrations of the active moiety were 25-32% lower with i.m. than oral dosing (P < 0.05) and fluctuations in plasma active-moiety levels were 32-42% lower with the i.m. than oral regimen. Symptoms of schizophrenia continued to improve after switching from oral to i.m. dosing. Long-acting risperidone was well tolerated locally and systematically. Although overall bioequivalence of the two formulations was established, the differences in pharmacokinetic profiles between the two formulations indicate potential benefits for long-acting risperidone.

  6. Thermo-sensitive hydrogel PLGA-PEG-PLGA as a vaccine delivery system for intramuscular immunization.

    PubMed

    Wang, Xiaoyan; Zhang, Yu; Xue, Wei; Wang, Hong; Qiu, Xiaozhong; Liu, Zonghua

    2016-11-25

    In this work, we explored the potential of thermo-sensitive PLGA-PEG-PLGA with sol-gel transition temperature around 32℃ as an intramuscular vaccine delivery system by using ovalbumin as a model antigen. First, in vitro release test showed that the PLGA-PEG-PLGA-deriving hydrogels could release ovalbumin in vitro in a more sustainable way. From fluorescence living imaging, 50-200 mg/mL of PLGA-PEG-PLGA formulations could release antigen in a sustainable manner in vivo, suggesting that the PLGA-PEG-PLGA hydrogel worked as an antigen-depot. Further, the sustainable antigen release from the PLGA-PEG-PLGA hydrogels increased antigen availability in the spleens of the immunized mice. The intramuscular immunization results showed that 50-200 mg/mL of PLGA-PEG-PLGA formulations promoted significantly more potent antigen-specific IgG immune response. In addition, 200 mg/mL of PLGA-PEG-PLGA formulation significantly enhanced the secretion of both Th1 and Th2 cytokines. From in vitro splenocyte proliferation assay, 50-200 mg/mL of PLGA-PEG-PLGA formulations all initiated significantly higher splenocyte activation. These results indicate that the thermo-sensitive and injectable PLGA-PEG-PLGA hydrogels (particularly, 200 mg/mL of PLGA-PEG-PLGA-based hydrogel) own promising potential as an intramuscular vaccine delivery system.

  7. A Biomimetic Approach to Active Self-Microencapsulation of Proteins in PLGA

    PubMed Central

    Shah, Ronak B.; Schwendeman, Steven P.

    2014-01-01

    A biomimetic approach to organic solvent-free microencapsulation of proteins based on the self-healing capacity of poly (DL)-lactic-co-glycolic acid (PLGA) microspheres containing glycosaminoglycan-like biopolymers (BPs), was examined. To screen BPs, aqueous solutions of BP [high molecular weight dextran sulfate (HDS), low molecular weight dextran sulfate (LDS), chondroitin sulfate (CS), heparin (HP), hyaluronic acid (HA), chitosan (CH)] and model protein lysozyme (LYZ) were combined in different molar and mass ratios, at 37 °C and pH 7. The BP-PLGA microspheres (20–63 µm) were prepared by a double water-oil-water emulsion method with a range of BP content, and trehalose and MgCO3 to control microclimate pH and to create percolating pores for protein. Biomimetic active self-encapsulation (ASE) of proteins [LYZ, vascular endothelial growth factor165 (VEGF) and fibroblast growth factor (FgF-20)] was accomplished by incubating blank BP-PLGA microspheres in low concentration protein solutions at ~24 °C, for 48 h. Pore closure was induced at 42.5 °C under mild agitation for 42 h. Formulation parameters of BP-PLGA microspheres and loading conditions were studied to optimize protein loading and subsequent release. LDS and HP were found to bind >95% LYZ at BP:LYZ >0.125 w/w, whereas HDS and CS bound > 80% LYZ at BP:LYZ of 0.25–1 and < 0.33, respectively. HA-PLGA microspheres were found to be not ideal for obtaining high protein loading (>2% w/w of LYZ). Sulfated BP-PLGA microspheres were capable of loading LYZ (~2–7 % w/w), VEGF (~ 4% w/w), and FgF-20 (~2% w/w) with high efficiency. Protein loading was found to be dependent on the loading solution concentration, with higher protein loading obtained at higher loading solution concentration within the range investigated. Loading also increased with content of sulfated BP in microspheres. Release kinetics of proteins was evaluated in-vitro with complete release media replacement. Rate and extent of release were

  8. A biomimetic approach to active self-microencapsulation of proteins in PLGA.

    PubMed

    Shah, Ronak B; Schwendeman, Steven P

    2014-12-28

    A biomimetic approach to organic solvent-free microencapsulation of proteins based on the self-healing capacity of poly (DL)-lactic-co-glycolic acid (PLGA) microspheres containing glycosaminoglycan-like biopolymers (BPs), was examined. To screen BPs, aqueous solutions of BP [high molecular weight dextran sulfate (HDS), low molecular weight dextran sulfate (LDS), chondroitin sulfate (CS), heparin (HP), hyaluronic acid (HA), chitosan (CH)] and model protein lysozyme (LYZ) were combined in different molar and mass ratios, at 37 °C and pH7. The BP-PLGA microspheres (20-63 μm) were prepared by a double water-oil-water emulsion method with a range of BP content, and trehalose and MgCO3 to control microclimate pH and to create percolating pores for protein. Biomimetic active self-encapsulation (ASE) of proteins [LYZ, vascular endothelial growth factor165 (VEGF) and fibroblast growth factor (FgF-20)] was accomplished by incubating blank BP-PLGA microspheres in low concentration protein solutions at ~24 °C, for 48 h. Pore closure was induced at 42.5 °C under mild agitation for 42h. Formulation parameters of BP-PLGA microspheres and loading conditions were studied to optimize protein loading and subsequent release. LDS and HP were found to bind >95% LYZ at BP:LYZ>0.125 w/w, whereas HDS and CS bound >80% LYZ at BP:LYZ of 0.25-1 and <0.33, respectively. HA-PLGA microspheres were found to be not ideal for obtaining high protein loading (>2% w/w of LYZ). Sulfated BP-PLGA microspheres were capable of loading LYZ (~2-7% w/w), VEGF (~4% w/w), and FgF-20 (~2% w/w) with high efficiency. Protein loading was found to be dependent on the loading solution concentration, with higher protein loading obtained at higher loading solution concentration within the range investigated. Loading also increased with content of sulfated BP in microspheres. Release kinetics of proteins was evaluated in-vitro with complete release media replacement. Rate and extent of release were found to depend

  9. Patient and Health Care Provider Perspectives on Long Acting Injectable Antipsychotics in Schizophrenia and the Introduction of Olanzapine Long-Acting Injection

    PubMed Central

    Wehring, Heidi J.; Thedford, Sheryl; Koola, Maju; Kelly, Deanna L.

    2011-01-01

    Olanzapine long acting injection has joined risperidone and paliperidone as the second generation long acting antipsychotic injection options for treatment of patients with schizophrenia. Long acting injections are important alternatives to oral medications for patients who have difficulty adhering to daily or multiple daily medication administrations, yet may be underutilized or not well understood. Patient perceptions, adherence, and preferences are important issues for health care providers to address when discussing treatment options with their patients. Reviewed here are overall patient and health care provider attitudes and perceptions regarding long acting injections and the details of olanzapine long acting injectable, the newest agent, and how it will fit in the marketplace. In addition, efficacy, safety, dosing and use data regarding this newest long acting agent are reviewed and compared to other available long acting agents. PMID:23293546

  10. Stabilization and immune response of HBsAg encapsulated within poly(lactic-co-glycolic acid) microspheres using HSA as a stabilizer.

    PubMed

    Xu, Wenjuan; He, Jintian; Wu, Guanghao; Xiong, Fangfang; Du, Huijuan; Wang, Gaizhen

    2015-12-30

    The aim of this study was to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres containing hepatitis B virus surface antigen (HBsAg) using human serum albumin (HSA) as a stabilizer. Lyophilization and emulsification of HBsAg solution with dichloromethane caused a considerable loss of HBsAg antigenicity. Thus, the effects of HSA and trehalose on HBsAg recovery during lyophilization and emulsification were investigated. Adding HSA to HBsAg solutions significantly improved antigen recovery to >90% during lyophilization and emulsification. The effects of co-encapsulated HSA on the characteristics of the PLGA microspheres and stability of HBsAg released from the microspheres were also investigated. The in vitro release test showed that HBsAg was released from the PLGA microspheres continuously over seventy days. A large amount of released HBsAg was inactive without co-encapsulation of HSA. On the contrary, with HSA co-encapsulation, the released HBsAg retained approximately 90% of its antigenicity. The single injection of the HBsAg-HSA-loaded PLGA microspheres in rats resulted in higher anti-HBsAg IgG and Th1 cytokine levels than the single injection of the HBsAg-loaded microspheres or two injections of the conventional aluminum-adjuvanted HBsAg vaccine. Based on these findings, the HBsAg-HSA-loaded PLGA microspheres could be an effective carrier for HBsAg and form a promising depot system.

  11. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1986-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  12. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1987-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  13. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1983-01-01

    Microspheres of acrolein homopolymers and co-polymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  14. Sustained release of risperidone from biodegradable microspheres prepared by in-situ suspension-evaporation process.

    PubMed

    An, Taekun; Choi, Juhyuen; Kim, Aram; Lee, Jin Ho; Nam, Yoonjin; Park, Junsung; Sun, Bo kyung; Suh, Hearan; Kim, Cherng-ju; Hwang, Sung-Joo

    2016-04-30

    Risperidone-loaded poly (D,L-lactide-co-glycolide) (PLGA) microspheres were prepared with a suspension-evaporation process with an aqueous suspension containing an in situ-formed aluminum hydroxide inorganic gel (SEP-AL process) and evaluated for encapsulation efficiency, particle size, surface morphology, glass transition temperature, in vitro drug release profile, and in vivo behavior. The SEP-AL microspheres were compared with conventional oil-in-water (O/W) emulsion solvent evaporation method using polyvinylalcohol (PVA) as an emulsifier (CP-PVA process). The microspheres were spherical in shape. DSC measurements showed that risperidone crystallinity was greatly reduced due to the homogeneous distribution of risperidone in PLGA microspheres. In vitro drug release profile from the microspheres showed a sigmoidal pattern of negligible initial burst up to 24h and minimal release (time-lag) for 7 days. After the lag phase, slow release took a place up to 25 days and then rapid release occurred sharply for 1 week. In vivo rat pharmacokinetic profile from the microspheres showed very low blood concentration level at the initial phase (up to 24h) followed by the latent phase up to 21 days. At the 3rd week, main phase started and the blood concentration of the drug increased up to the 5th week, and then gradually decreased. The risperidone-loaded PLGA microspheres produced by SEP-AL process showed excellent controlled release characteristics for the effective treatment of schizophrenia patients.

  15. In vitro drug release behavior, mechanism and antimicrobial activity of rifampicin loaded low molecular weight PLGA-PEG-PLGA triblock copolymeric nanospheres.

    PubMed

    Gajendiran, M; Divakar, S; Raaman, N; Balasubramanian, S

    2013-12-01

    Poly (lactic-co-glycolic acid) (PLGA (92:8)) and a series of PLGA-PEG-PLGA tri block copolymers were synthesized by direct melt polycondensation. The copolymers were characterized by FTIR, and 1HNMR spectroscopic techniques, viscosity, gel permeation chromatography (GPC) and powder x-ray diffraction (XRD). The rifampicin (RIF) loaded polymeric nanospheres (NPs) were prepared by ultrasonication-W/O emulsification technique. The NPs have been characterized by field emission scanning electron microscopy (FESEM), TEM, powder X-ray diffraction (XRD), UVvisible spectroscopy and DLS measurements. The drug loaded triblock copolymeric NPs have five folds higher drug content and drug loading efficiency than that of PLGA microspheres (MPs). The in vitro drug release study shows that the drug loaded NPs showed an initial burst release after that sustained release up to 72 h. All the triblock copolymeric NPs follow anomalous drug diffusion mechanism while the PLGA MPs follow non-Fickian super case-II mechanism up to 12 h. The overall in-vitro release follows second order polynomial kinetics up to 72 h. The antimicrobial activity of the RIF loaded polymer NPs was compared with that of pure RIF and tetracycline (TA). The RIF loaded triblock copolymeric NPs inhibited the bacterial growth more effectively than the pure RIF and TA.

  16. Long-acting Injectable Antipsychotics in First-episode Schizophrenia

    PubMed Central

    Jeong, Hyun-Ghang

    2013-01-01

    Antipsychotic medications are important for the successful management of schizophrenia. Continuous treatment with medication is superior in relapse prevention and non-adherence to antipsychotic medication is associated with a poor clinical outcome. Long-acting injectable antipsychotics (LAIs) that can guarantee adherence to a treatment regimen could be a useful treatment option. With the introduction of second-generation atypical antipsychotics-long acting injection (SGA-LAI), the risks for extrapyramidal adverse events are decreased. The indications for SGA-LAI have been extended from chronic, stabilized patients to acute psychotic patients. Some studies investigated the use of LAI in first-episode schizophrenia patients and raised the possibility of prescribing LAI as a treatment option. However, there is still limited research using LAI in first-episode schizophrenia. More well-designed, randomized, controlled clinical trials using SGA-LAIs in first episode schizophrenia are needed. Additionally, studies on side effects of SGA-LAI in long-term use are required prior to recommending LAI for patients with first episode schizophrenia. PMID:23678347

  17. A qualitative analysis of long-acting reversible contraception.

    PubMed

    Sundstrom, Beth; Baker-Whitcomb, Annalise; DeMaria, Andrea L

    2015-07-01

    Increasing access to long-acting reversible contraception (LARC), including the intrauterine device and the implant is a public health and clinical imperative to reduce rates of unintended pregnancy. In 2012, the American College of Obstetricians and Gynecologists recommended these methods for all women, including adolescents. Little research explores why young women reject these safe, effective contraceptive methods. A total of 53 women aged 18-24 years completed in-depth interviews. Analytical techniques from the grounded theory approach were used to identify patterns and themes across the data. Participants initiated hormonal contraception for "the pill's" beneficial side effects and believed a myth of perfect use, which constructed a false choice of LARC methods. Barriers to LARC options included access, medical resistance, and cost. Participants described a sense of unease about methods perceived as "alien." These women underestimated the risks of oral contraceptive pills and overestimated the risks of long-acting reversible contraception, including infertility. The myth of perfect use emerged as participants wanted to be in control by taking "the pill" every day; however, many described imperfect adherence. Findings include strategies for public health professionals and health care providers to distribute satisfactory and effective contraception for young women. Effective health communication campaigns will emphasize the desirable side effects, safety and increased effectiveness of LARC methods.

  18. Biodegradable Polymeric Microsphere-Based Drug Delivery for Inductive Browning of Fat

    PubMed Central

    Jiang, Chunhui; Kuang, Liangju; Merkel, Madeline P.; Yue, Feng; Cano-Vega, Mario Alberto; Narayanan, Naagarajan; Kuang, Shihuan; Deng, Meng

    2015-01-01

    Brown and beige adipocytes are potent therapeutic agents to increase energy expenditure and reduce risks of obesity and its affiliated metabolic symptoms. One strategy to increase beige adipocyte content is through inhibition of the evolutionarily conserved Notch signaling pathway. However, systemic delivery of Notch inhibitors is associated with off-target effects and multiple dosages of application further faces technical and translational challenges. Here, we report the development of a biodegradable polymeric microsphere-based drug delivery system for sustained, local release of a Notch inhibitor, DBZ. The microsphere-based delivery system was fabricated and optimized using an emulsion/solvent evaporation technique to encapsulate DBZ into poly(lactide-co-glycolide) (PLGA), a commonly used biodegradable polymer for controlled drug release. Release studies revealed the ability of PLGA microspheres to release DBZ in a sustained manner. Co-culture of white adipocytes with and without DBZ-loaded PLGA microspheres demonstrated that the released DBZ retained its bioactivity, and effectively inhibited Notch and promoted browning of white adipocytes. Injection of these DBZ-loaded PLGA microspheres into mouse inguinal white adipose tissue depots resulted in browning in vivo. Our results provide the encouraging proof-of-principle evidence for the application of biodegradable polymers as a controlled release platform for delivery of browning factors, and pave the way for development of new translational therapeutic strategies for treatment of obesity. PMID:26617571

  19. Long acting porous microparticle for pulmonary protein delivery.

    PubMed

    Kwon, Min Jung; Bae, Jun Ho; Kim, Jung Ju; Na, Kun; Lee, Eun Seong

    2007-03-21

    This study investigated the porous-microparticle (PM) with low mass density and large size for pulmonary drug delivery. PM was prepared by the water-in-oil-in-water (W(1)/O/W(2)) multi-emulsion method with cyclodextrin derivative as a porogen and a stabilizer of peptide drugs. Herein, sucrose ethyl acetate (SAIB) was incorporated in PM for long acting protein release. In vitro release studies, the rapid release rate of proteins from PM was reduced due to the high viscosity of the added SAIB. As a result, BSA release from PM continued up to 7 days. This result suggests that PM having sustained release characteristics may be successfully applied for long-term pulmonary administration of protein or peptide drug. In addition, it is expected that these particles arrive at a deep lung epithelium due to low density (high porosity) and limit macrophage recognition because of big particle size (more than 5 microm).

  20. Control-released basic fibroblast growth factor-loaded poly-lactic-co-glycolic acid microspheres promote sciatic nerve regeneration in rats

    PubMed Central

    Si, Hai-Bo; Zeng, Yi; Lu, Yan-Rong; Cheng, Jing-Qiu; Shen, Bin

    2017-01-01

    Although peripheral nerve injury may result in a loss of function in innervated areas, the most effective method for nerve regeneration remains to be determined. The aim of the present study was to investigate the effect of control-released basic fibroblast growth factor (bFGF)-loaded poly-lactic-co-glycolic acid (PLGA) microspheres on sciatic nerve regeneration following injury in rats. bFGF-PLGA microspheres were prepared and their characteristics were evaluated. The sciatic nerve was segmentally resected to create a 10 mm defect in 36 Sprague Dawley (SD) rats and, following the anastomosis of the nerve ends with a silicone tube, bFGF-PLGA microspheres, free bFGF or PBS were injected into the tube (n=12 in each group). The outcome of nerve regeneration was evaluated using the sciatic function index (SFI), electrophysiological test and histological staining at 6 weeks and 12 weeks post-surgery. The bFGF-PLGA microspheres were successfully synthesized with an encapsulation efficiency of 66.43%. The recovery of SFI and electrophysiological values were significantly greater (P<0.05), and morphological and histological observations were significantly greater (P<0.05) in bFGF-PLGA microspheres and bFGF groups compared with those in the PBS group, and the quickest recovery was observed in the bFGF-PLGA microspheres group. In conclusion, the bFGF-PLGA microspheres may promote nerve regeneration and functional recovery in the sciatic nerve, and may have potential therapeutic applications in peripheral nerve regeneration. PMID:28352311

  1. In vitro-in vivo correlation of parenteral risperidone polymeric microspheres.

    PubMed

    Shen, Jie; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

    2015-11-28

    The objective of the present study was to determine whether an in vitro-in vivo correlation (IVIVC) can be established for polymeric microspheres that are equivalent in formulation composition but prepared with different manufacturing processes. Risperidone was chosen as a model therapeutic and poly(lactic-co-glycolic acid) (PLGA) with similar molecular weight as that used in the commercial product Risperdal® Consta® was used to prepare risperidone microspheres. Various manufacturing processes were investigated to produce the risperidone microspheres with similar drug loading (approx. 37%) but distinctly different physicochemical properties (e.g. porosity, particle size and particle size distribution). In vitro release of the risperidone microspheres was investigated using different release testing methods (such as sample-and-separate and USP apparatus 4). In vivo pharmacokinetic profiles of the risperidone microsphere formulations following intramuscular administration were determined using a rabbit model. Furthermore, the obtained pharmacokinetic profiles were deconvoluted using the Loo-Riegelman method and the calculated in vivo release was compared with the in vitro release of these microspheres. Level A IVIVCs were established and validated for the compositionally equivalent risperidone microspheres based on the in vitro release data obtained using USP apparatus 4. The developed IVIVCs demonstrated good predictability and were robust. These results showed that the developed USP apparatus 4 method was capable of discriminating PLGA microspheres that are equivalent in formulation composition but with manufacturing differences and predicting their in vivo performance in the investigated animal model.

  2. One-step fabrication of inorganic/organic hybrid microspheres with tunable surface texture for controlled drug release application.

    PubMed

    Dong, Hua; Tang, Guannan; Ma, Ting; Cao, Xiaodong

    2016-01-01

    In this paper, we report one-step fabrication of poly(lactide-co-glycolic acid)/titanium oxide (PLGA/TiO2) hybrid microspheres with tunable surface texture via droplet-based microfluidics. Surface texture of microspheres can be continuously tuned by changing the mass ratio between titanium tetraisopropoxide (TTIP) and PLGA in the dispersed phase. The fast hydrolysis of TTIP on the droplet surface can generate a thin shell membrane, resulting in a wrinkled surface after extraction of organic solvent. In vitro drug release monitoring of tanshinone IIA-loaded PLGA/TiO2 hybrid microsphere reveals that surface texture can affect the drug release rate to a large extent without sacrificing the drug encapsulation efficiency. Our finding might benefit the sustained drug delivery where variable drug release rate and high drug encapsulation efficiency are both required.

  3. Long-acting injectable antipsychotics: focus on olanzapine pamoate

    PubMed Central

    Lindenmayer, JP

    2010-01-01

    Medication non-adherence in patients with schizophrenia continues to be a significant problem and threatens successful treatment outcomes. Medication non-adherence is often associated with negative consequences, including symptom exacerbation, more frequent emergency room visits, re-hospitalizations and relapse. Long-acting injectable (LAI) forms of antipsychotics allow for rapid identification of non-adherence, obviate the need for the patient to take the medication on a daily basis and increase adherence to some significant degree. Eli Lilly has developed a long-acting depot formulation of olanzapine, olanzapine pamoate, which has recently been approved by the FDA for the US market, and which will be reviewed here. Olanzapine LAI appears to be an effective antipsychotic at dosages of 210 mg every 2 weeks, 300 mg every 2 weeks and 405 mg every 4 weeks in patients with acute schizophrenia, and at 150 mg every 2 weeks, 300 mg every 2 weeks and at 405 mg every 4 weeks for the maintenance treatment of stable patients. Oral supplementation appears not to be needed, particularly not at the onset of treatment with the LAI as is necessary with risperidone LAI. Its efficacy is in general comparable to the efficacy seen with oral olanzapine at a corresponding dose. The side effect profile is also comparable to the side effects observed with oral olanzapine, including lower rates of extrapyramidal symptoms, prolactin elevation and cardiovascular side effects, but significant metabolic effects. The latter include significant weight gain, lipid abnormalities and glucose dysregulation. While the injection site adverse events are overall mild, the most significant serious adverse event is the post-injection delirium sedation syndrome (PDSS). While rare, this syndrome results from inadvertent intravascular injection of olanzapine LAI and can cause a range of olanzapine overdose-type of symptoms. Olanzapine LAI needs therefore to be administered by trained personnel in settings

  4. Fluorescent microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, A.

    1978-01-01

    Latex particles with attached antibodies have potential biochemical and environmental applications. Human red blood cells and lymphocytes have been labeled with fluorescent microspheres by either direct or indirect immunological technique. Immunolatex spheres can also be used for detecting and localizing specific cell surface receptors. Hormones and toxins may also be bondable.

  5. Injectable polymer microspheres enhance immunogenicity of a contraceptive peptide vaccine.

    PubMed

    Cui, Chengji; Stevens, Vernon C; Schwendeman, Steven P

    2007-01-05

    Advanced contraceptive peptide vaccines suffer from the unavailability of adjuvants capable of enhancing the antibody response with acceptable safety. We sought to overcome this limitation by employing two novel poly(lactic-co-glycolic acid) (PLGA) microsphere formulations to deliver a synthetic human chorionic gonadotropin (hCG) peptide antigen co-synthesized with a T-cell epitope from tetanus toxoid (TT), C-TT2-CTP35: surface-conjugated immunogen to induce phagocytosis; and encapsulated peptide to provide a depot effect, with MgCO(3) co-encapsulated in the polymer to neutralize acidity from the biodegrading PLGA polyester. A single immunization of encapsulated peptide in rabbits elicited a stronger antibody response with equivalent duration relative to a positive control--three injections of the peptide administered in a squalene-based water-in-oil emulsion. Surface-conjugated peptide was less effective but enhanced antibody levels at 1/5 the dose, relative to soluble antigen. Most remarkable and unexpected was the finding that co-encapsulation of base was essential to attain the powerful adjuvant effect of the PLGA-MgCO(3) system, as the MgCO(3)-free microspheres were completely ineffective. A promising contraceptive hCG peptide vaccine with acceptable side effects (i.e., local tissue reactions) was achieved by minimizing PLGA and MgCO(3) doses, without significantly affecting antibody response.

  6. Possible interaction between letrozole and long-acting injectable zuclopenthixol.

    PubMed

    Lertxundi, Unax; Hernandez, Rafael; Albeniz, Juan Medrano; Echaburu, Saioa Domingo; Ruiz, Borja; García, Montserrat García; Aguirre, Carmelo

    2015-01-01

    Mrs A, a 68-year-old woman with paranoid schizophrenia, was on long-term psychiatric treatment with long-acting intramuscular zuclopenthixol, quetiapine and alprazolam when, in April 2012, she was diagnosed with right breast infiltrating ductal carcinoma. After starting treatment with letrozole on 4 July, Mrs A progressively developed extrapyramidal symptoms and these were particularly evident after each zuclopenthixol administration. On 9 January, both quetiapine and alprazolam were stopped due to excessive lethargy. After the administration of the last dose of zuclopenthixol on 26 January, she presented with sedation, sialorrhea, festinant gait, axial dystonia and dysphagia, all of which were severe. The introduction of letrozole was the only change that had been made to her pharmacotherapeutic regimen in that period. The rest of the findings on neurological examination were normal. Renal function was adequate. Slow symptom onset and progressive worsening until full-blown clinical presentation after 6 months, and the dramatic improvement in the clinical picture achieved 2 days after treatment with biperiden, suggests a long-term insidious interaction leading to zuclopenthixol accumulation. To the best of our knowledge, this is the first report of a possible interaction between letrozole and zuclopenthixol. We consider that it warrants further investigation. In the meanwhile, physicians should be aware of the occurrence of this potentially serious drug-drug interaction.

  7. Long-Acting Beta Agonists Enhance Allergic Airway Disease

    PubMed Central

    Knight, John M.; Mak, Garbo; Shaw, Joanne; Porter, Paul; McDermott, Catherine; Roberts, Luz; You, Ran; Yuan, Xiaoyi; Millien, Valentine O.; Qian, Yuping; Song, Li-Zhen; Frazier, Vincent; Kim, Choel; Kim, Jeong Joo; Bond, Richard A.; Milner, Joshua D.; Zhang, Yuan; Mandal, Pijus K.; Luong, Amber; Kheradmand, Farrah

    2015-01-01

    Asthma is one of the most common of medical illnesses and is treated in part by drugs that activate the beta-2-adrenoceptor (β2-AR) to dilate obstructed airways. Such drugs include long acting beta agonists (LABAs) that are paradoxically linked to excess asthma-related mortality. Here we show that LABAs such as salmeterol and structurally related β2-AR drugs such as formoterol and carvedilol, but not short-acting agonists (SABAs) such as albuterol, promote exaggerated asthma-like allergic airway disease and enhanced airway constriction in mice. We demonstrate that salmeterol aberrantly promotes activation of the allergic disease-related transcription factor signal transducer and activator of transcription 6 (STAT6) in multiple mouse and human cells. A novel inhibitor of STAT6, PM-242H, inhibited initiation of allergic disease induced by airway fungal challenge, reversed established allergic airway disease in mice, and blocked salmeterol-dependent enhanced allergic airway disease. Thus, structurally related β2-AR ligands aberrantly activate STAT6 and promote allergic airway disease. This untoward pharmacological property likely explains adverse outcomes observed with LABAs, which may be overcome by agents that antagonize STAT6. PMID:26605551

  8. Long-Acting Beta Agonists Enhance Allergic Airway Disease.

    PubMed

    Knight, John M; Mak, Garbo; Shaw, Joanne; Porter, Paul; McDermott, Catherine; Roberts, Luz; You, Ran; Yuan, Xiaoyi; Millien, Valentine O; Qian, Yuping; Song, Li-Zhen; Frazier, Vincent; Kim, Choel; Kim, Jeong Joo; Bond, Richard A; Milner, Joshua D; Zhang, Yuan; Mandal, Pijus K; Luong, Amber; Kheradmand, Farrah; McMurray, John S; Corry, David B

    2015-01-01

    Asthma is one of the most common of medical illnesses and is treated in part by drugs that activate the beta-2-adrenoceptor (β2-AR) to dilate obstructed airways. Such drugs include long acting beta agonists (LABAs) that are paradoxically linked to excess asthma-related mortality. Here we show that LABAs such as salmeterol and structurally related β2-AR drugs such as formoterol and carvedilol, but not short-acting agonists (SABAs) such as albuterol, promote exaggerated asthma-like allergic airway disease and enhanced airway constriction in mice. We demonstrate that salmeterol aberrantly promotes activation of the allergic disease-related transcription factor signal transducer and activator of transcription 6 (STAT6) in multiple mouse and human cells. A novel inhibitor of STAT6, PM-242H, inhibited initiation of allergic disease induced by airway fungal challenge, reversed established allergic airway disease in mice, and blocked salmeterol-dependent enhanced allergic airway disease. Thus, structurally related β2-AR ligands aberrantly activate STAT6 and promote allergic airway disease. This untoward pharmacological property likely explains adverse outcomes observed with LABAs, which may be overcome by agents that antagonize STAT6.

  9. Long-acting injectable antipsychotics: recommendations for clinicians.

    PubMed

    Malla, Ashok; Tibbo, Phil; Chue, Pierre; Levy, Emmanuelle; Manchanda, Rahul; Teehan, Michael; Williams, Richard; Iyer, Srividya; Roy, Marc-André

    2013-05-01

    A major source of limitation to the real effectiveness of antipsychotics is the high rate of patient nonadherence or, more frequently, partial adherence. Using long-acting injectable (LAI) formulations is likely to reduce the impact of such adherence problems. Conversely, the use of LAIs in Canada remains low relative to many other jurisdictions. Based on effectiveness data from randomized control trials and other, less rigorous, studies, as well as our 2 qualitative studies exploring numerous issues around the use of LAIs, including their low use, we put forward 10 different recommendations for consideration by clinicians. These are also based on the experience of many clinicians and clinician scientists. These recommendations address mostly clinical challenges associated with the use of LAIs. Their application in clinical settings is illustrated in our report through several case examples highlighting the large variation across patients and different phases of illness. It is recommended that LAIs should be considered as a treatment option for psychotic disorders across all phases, including the first 2 to 5 critical years.

  10. Pharmacokinetics and pharmacodynamics of controlled release insulin loaded PLGA microcapsules using dry powder inhaler in diabetic rats.

    PubMed

    Hamishehkar, Hamed; Emami, Jaber; Najafabadi, Abdolhossien Rouholamini; Gilani, Kambiz; Minaiyan, Mohsen; Hassanzadeh, Kambiz; Mahdavi, Hamid; Koohsoltani, Maryam; Nokhodchi, Ali

    2010-03-01

    The pulmonary route is an alternative route of administration for the systemic delivery of peptide and proteins with short-half lives. A long-acting formulation of insulin was prepared by encapsulation of protein into respirable, biodegradable microcapsules prepared by an oil in oil emulsification/solvent evaporation method. Insulin-loaded PLGA microcapsules prepared as a dry powder inhaler formulation were administered via the pulmonary route to diabetic rats and serum insulin and glucose concentrations were monitored. Control treatments consisted of respirable spray-dried insulin (RSDI) powder administered by intratracheal insufflation, insulin-loaded PLGA microcapsules and NPH (long-acting) insulin administered by subcutaneous (SC) administration. Pharmacokinetic analysis demonstrated that insulin administered in PLGA microcapsules illustrated a sustained release profile which resulted in a longer mean residence time, 4 and 5 fold longer than those after pulmonary administration of RSDI and SC injection of NPH insulin, respectively. Accordingly, the hypoglycemic profile followed a stable and sustained pattern which remained constant between 10 and 48 h. Results of the in vitro experiments were in good agreement with those of in vivo studies. Bronchoalveolar lavage fluid analysis indicated that microcapsules administration did not increase the activities of lactate dehydrogenase and total protein. However, histological examination of the lung tissue indicated a minor but detectable effect on the normal physiology of the rat lung. These findings suggest that the encapsulation of peptides and proteins into PLGA microcapsules technique could be a promising controlled delivery system for pulmonary administration.

  11. Computational Intelligence Modeling of the Macromolecules Release from PLGA Microspheres—Focus on Feature Selection

    PubMed Central

    Zawbaa, Hossam M.; Szlȩk, Jakub; Grosan, Crina; Jachowicz, Renata; Mendyk, Aleksander

    2016-01-01

    Poly-lactide-co-glycolide (PLGA) is a copolymer of lactic and glycolic acid. Drug release from PLGA microspheres depends not only on polymer properties but also on drug type, particle size, morphology of microspheres, release conditions, etc. Selecting a subset of relevant properties for PLGA is a challenging machine learning task as there are over three hundred features to consider. In this work, we formulate the selection of critical attributes for PLGA as a multiobjective optimization problem with the aim of minimizing the error of predicting the dissolution profile while reducing the number of attributes selected. Four bio-inspired optimization algorithms: antlion optimization, binary version of antlion optimization, grey wolf optimization, and social spider optimization are used to select the optimal feature set for predicting the dissolution profile of PLGA. Besides these, LASSO algorithm is also used for comparisons. Selection of crucial variables is performed under the assumption that both predictability and model simplicity are of equal importance to the final result. During the feature selection process, a set of input variables is employed to find minimum generalization error across different predictive models and their settings/architectures. The methodology is evaluated using predictive modeling for which various tools are chosen, such as Cubist, random forests, artificial neural networks (monotonic MLP, deep learning MLP), multivariate adaptive regression splines, classification and regression tree, and hybrid systems of fuzzy logic and evolutionary computations (fugeR). The experimental results are compared with the results reported by Szlȩk. We obtain a normalized root mean square error (NRMSE) of 15.97% versus 15.4%, and the number of selected input features is smaller, nine versus eleven. PMID:27315205

  12. Liraglutide-loaded poly(lactic-co-glycolic acid) microspheres: Preparation and in vivo evaluation.

    PubMed

    Wu, Junzi; Williams, Gareth R; Branford-White, Christopher; Li, Heyu; Li, Yan; Zhu, Li-Min

    2016-09-20

    In this work, we sought to generate sustained-release injectable microspheres loaded with the GLP-1 analogue liraglutide. Using water-in-oil-in-water double emulsion methods, poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with liraglutide were prepared. The microspheres gave sustained drug release over 30days, with cumulative release of up to 90% reached in vitro. The microspheres were further studied in a rat model of diabetes, and their performance compared with a group given daily liraglutide injections. Reduced blood sugar levels were seen in the microsphere treatment groups, with the results being similar to those obtained with conventional injections between 10 and 25days after the commencement of treatment. After 5 and 30days of treatment, the microspheres seem a little slower to act than the injections. The pathology of the rats' spleen, heart, kidney and lungs was probed after the 30-day treatment period, and the results indicated that the microspheres were safe and had beneficial effects on the liver, reducing the occurrence of fatty deposits seen in untreated diabetic rats. Moreover, in terms of liver, renal and cardiac functions, and blood lipid and antioxidant levels, the microspheres were as effective as the injections. The expression of several proteases linked to the metabolism of aliphatic acids and homocysteine was promoted by the microsphere formulations. Inflammatory markers in the microsphere treatment groups were somewhat higher than the injection group, however. The liraglutide/PLGA microspheres prepared in this work are overall shown to be efficacious in a rat model of diabetes, and we thus believe they have strong potential for clinical use.

  13. Effects of Discontinuation of Paliperidone Long-Acting Injectable After Switching from Risperidone Long-Acting Injectable Switching

    PubMed Central

    Watanabe, Takafumi; Yamada, Atsurou

    2016-01-01

    Background Risperidone long-acting injection (RLAI) is increasingly being switched to paliperidone palmitate (PP) because of several benefits. However, this switching is not always successful. Methods We examined patient profiles following discontinuation of PP after switching from RLAI. We collected the electronic records of 24 patients with schizophrenia who had switched from RLAI to PP treatment at our hospital between November 2013 and March 2014. Twelve patients continued PP injection for over 1 year (PP-continuers), the other 12 patients discontinued within 1 year (PP-discontinuers), and both groups were followed up until December 31, 2014. Results PP-discontinuers had significantly shorter RLAI-administration period (mean 73.1 ± 59.0 weeks versus 148.5 ± 75.0 weeks), and lower chlorpromazine (CP) equivalent mean doses (mean 553.5 ± 251.0 mg versus 1002.5 ± 529.3 mg) compared with PP-continuers. The CP equivalent mean dose of PP-discontinuers had increased at the time of discontinuation and their social status became significantly worse. Six PP-discontinuers (50%) re-switched to RLAI, and their social status was not significantly worse at the end of the observation period. Conclusions On switching from RLAI to PP, we need to consider that some patients have had a shorter RLAI-administration period and may require lower amounts of antipsychotics. PMID:27738379

  14. Aripiprazole Lauroxil Long-Acting Injectable: The Latest Addition to Second-Generation Long-Acting Agents.

    PubMed

    Aggarwal, Arpit; Gopalakrishna, Ganesh; Lauriello, John

    2016-01-01

    Antipsychotics have long been the mainstay for the treatment of schizophrenia and other psychotic disorders. Long-acting injectables (LAI) of antipsychotics-provided once every two weeks to once every three months-promise to reduce the incidence of nonadherence. ARISTADA(™) (aripiprazole lauroxil; ALLAI) extended-release injectable suspension was approved by the U.S. Food and Drug Administration in October 2015 for the treatment of schizophrenia, and is the newest entrant in the LAI market. ALLAI is available as a single-use, pre-filled syringe, can be started in three different dosages, and also has the option of every six-week dosing. Treatment with oral aripiprazole is recommended for the first twenty-one days after the first ALLAI injection, which is a potential disadvantage. Adverse effects include sensitivity to extrapyramidal symptoms, especially akathisia, which is well documented in other aripiprazole preparations. There is no available data comparing ALLAI to other antipsychotics, and more head-to-head trials comparing different LAI formulations are needed. Based on the available data, ALLAI is an effective and safe option for treatment of schizophrenia. Further studies and post-marketing data will provide better understanding of this formulation.

  15. Formulation optimization of long-acting depot injection of aripiprazole by using D-optimal mixture design.

    PubMed

    Nahata, Tushar; Saini, T R

    2009-01-01

    Non-adherence to medication specifications is a major cause for poor outcomes in the therapy of schizophrenia. In situ implantable preparation of aripiprazole, an atypical antipsychotic drug, was intended with the aim to improve the patient compliance and to offer an effective antipsychotic drug therapy. D-optimal mixture design was employed to design and optimize long-acting depot injection of aripiprazole using polylactide-co-glycolide (PLGA) 50:50, 75:25, 85:15, and cholesterol as release rate-retarding material. Desirability technique was used for the optimization of formulation. Predicted optimized formulation was experimentally validated, and it was found that the developed formulation releases the drug for a 14-day time period. The optimized formulation showed that the cholesterol-containing formulation exhibits a better drug release profile. The pharmacokinetic studies confirmed that the developed cholesterol-based depot formulation was capable of releasing the drug for a time period of more than 14 days. The implant formulation was sterilized by gamma radiation and ethylene oxide sterilization method. The D-optimal mixture design was proved to be an efficient technique for the formulation optimization.

  16. Pharmacokinetics of olanzapine long-acting injection: the clinical perspective

    PubMed Central

    Kraemer, Susanne; Bergstrom, Richard F.; Detke, Holland C.

    2014-01-01

    Olanzapine long-acting injection (OLAI) is a sustained-release depot antipsychotic for the treatment of schizophrenia in adults. Our objective was to explain the pharmacokinetics of OLAI to provide clinical insight. Simulation models and data from clinical trials are presented. Olanzapine concentrations were observed immediately upon injection. Half-life was ∼30 days, controlled by the slow rate of intramuscular absorption rather than the 30-h elimination rate-based half-life of oral olanzapine. As each injection builds on the drug still being released from previous injections, concentrations increase gradually until a steady state is reached after ∼3 months. Concentrations were similar to oral olanzapine and proportional to the dose; the average steady-state concentrations (10th–90th percentile) for the 150, 210, and 300 mg/2-week doses were 16–32, 15–55, and 20–67 ng/ml, respectively, and those for the 300 and 405 mg/4-week doses were 19–48 and 19–62 ng/ml, respectively. Peak concentrations most often occurred at 2–4 days after injection. Peak-to-trough fluctuation was greater for the 4-week dosing interval than the 2-week one, with no apparent clinical ramifications for these differences. Trough concentrations were above the lower end of the therapeutic range, even at the first injection. Long-term use up to 6 years indicated no additional accumulation. The impact of smoking and sex was similar, but less pronounced than for oral olanzapine. PMID:24815672

  17. Long-acting reversible contraception: a review in special populations.

    PubMed

    Prescott, Gina M; Matthews, Christina M

    2014-01-01

    Almost half of the pregnancies in the United States are unintended. Currently available contraceptive methods are highly efficacious, but the most commonly used methods rely on patients for appropriate use. There has been a push to advocate for long-acting reversible contraceptives (LARCs) as first-line methods because they are placed by medical professionals and are the most effective form of reversible contraception available. There are four LARCs currently available in the United States: the Copper T intrauterine device, two forms of the levonorgestrel intrauterine system, and the etonogestrel subdermal implant. Once inserted, they can be left in place for 3-10 years, depending on the device. Some of these devices have been available for a number of years, but their use is limited in the United States due to controversies and misconceptions. A MEDLINE search from 1990-2012 was conducted to identify articles describing the use of LARCs in populations with limited data, including postpartum women, adolescents and nulliparous women, and women with sexually transmitted infections, including human immunodeficiency virus (HIV). Health care provider safety concerns surrounding intrauterine device (IUD) expulsions and infection are issues for use in adolescents and nulliparous women. Concern regarding IUD expulsion in the postpartum population questions the benefit of immediate versus delayed insertion, and the progestin effect in the levonorgestrel IUD and etonogestrel implant is of theoretic concern for breastfeeding women. In women with HIV, concerns have been raised about increased viral shedding with the IUD and drug interactions with the progestin methods. Many misconceptions surrounding LARCs are unfounded, but individual risk factors may leave LARC users at risk of unintended pregnancy if not addressed properly.

  18. Electrospun aligned PLGA and PLGA/gelatin nanofibers embedded with silica nanoparticles for tissue engineering.

    PubMed

    Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Ghaedi, Kamran; Salehi, Hossein; Arpanaei, Ayyoob

    2015-08-01

    Aligned poly lactic-co-glycolic acid (PLGA) and PLGA/gelatin nanofibrous scaffolds embedded with mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. The mean diameters of nanofibers were 641±24 nm for the pure PLGA scaffolds vs 418±85 nm and 267±58 nm for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The contact angle measurement results (102°±6.7 for the pure PLGA scaffold vs 81°±6.8 and 18°±8.7 for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively) revealed enhanced hydrophilicity of scaffolds upon incorporation of gelatin and MSNPs. Besides, embedding the scaffolds with MSNPs resulted in improved tensile mechanical properties. Cultivation of PC12 cells on the scaffolds demonstrated that introduction of MSNPs into PLGA and PLGA/gelatin matrices leads to the improved cell attachment and proliferation as well as long cellular processes. DAPI staining results indicated that cell proliferations on the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds were strikingly (nearly 2.5 and 3 folds, respectively) higher than that on the aligned pure PLGA scaffolds. These results suggest superior properties of silica nanoparticles-incorporated PLGA/gelatin eletrospun nanofibrous scaffolds for the stem cell culture and tissue engineering applications.

  19. The potential of using biodegradable microspheres in retinal diseases and other intraocular pathologies.

    PubMed

    Herrero-Vanrell, Rocío; Bravo-Osuna, Irene; Andrés-Guerrero, Vanessa; Vicario-de-la-Torre, Marta; Molina-Martínez, Irene Teresa

    2014-09-01

    Pathologies affecting the posterior segment of the eye are one of the major causes of blindness in developed countries and are becoming more prevalent due to the increase in society longevity. Successful therapy of diseases affecting the back of the eye requires effective concentrations of the active substance maintained during a long period of time in the intraocular target site. Treatment of vitreoretinal diseases often include repeated intravitreous injections that are associated with adverse effects. Local administration of biodegradable microspheres offers an excellent alternative to multiple administrations, as they are able to deliver the therapeutic molecule in a controlled fashion. Furthermore, injection of microparticles is performed without the need for surgical procedures. As most of the retinal diseases are multifactorial, microspheres result especially promising because they can be loaded with more than one active substance and complemented with the inclusion of additives with pharmacological properties. Personalized therapy can be easily achieved by changing the amount of administered microspheres. Contrary to non-biodegradable devices, biodegradable PLA and PLGA microspheres disappear from the site of administration after delivering the drug. Furthermore, microspheres prepared from these mentioned biomaterials are well tolerated after periocular and intravitreal injections in animals and humans. After injection, PLA and PLGA microspheres suffer aggregation behaving like an implant. Biodegradable microspheres are potential tools in regenerative medicine for retinal repair. According to the reported results, presumably a variety of microparticulate formulations for different ophthalmic therapeutic uses will be available in the clinical practice in the near future.

  20. Bacterial protease triggered release of biocides from microspheres with an oily core.

    PubMed

    Craig, Marina; Amiri, Mona; Holmberg, Krister

    2015-03-01

    This study deals with controlled release of drugs to a Staphylococcus aureus infected site from microspheres with an oily core and a polymeric shell. The intended use of the microspheres is for chronic wounds and the microspheres may be administered in the form of a wash liquid or incorporated in a gel. Chronic wounds often carry infection, and the use of microspheres with drug release triggered by the bacterial infection is therefore of interest. A lipophilic drug or a model of the drug was dissolved in an oil and the oil phase was dispersed into an o/w emulsion. A nanofilm shell was then assembled around the oil droplets with the layer-by-layer technique using the two biodegradable polypeptides anionic poly-L-glutamic acid (PLGA) and cationic poly-L-lysine (PLL). Since S. aureus exudes proteases such as glutamyl endopeptidase (V8) during colonization and infection, its substrate specificity was key when assembling the nanofilm. Since V8 is known to be substrate specific to the Glu-X bond, PLGA was chosen as the terminating layer of the nanofilm. Crosslinking the nanofilm after assembly lead to increased stability of the microspheres. It was shown that in a non-infectious environment, i.e. when a human wound enzyme, HNE (human neutrophile elastase), was present, the microspheres remained intact. The staphylococcal protease V8, on the other hand, readily catalyzed degradation of the microspheres, thus releasing the drug when triggered by the infectious environment.

  1. Comparative assessment of in vitro release kinetics of calcitonin polypeptide from biodegradable microspheres.

    PubMed

    Prabhu, Sunil; Sullivan, Jennifer L; Betageri, Guru V

    2002-01-01

    The objective of our study was to compare the in vitro release kinetics of a sustained-release injectable microsphere formulation of the polypeptide drug, calcitonin (CT), to optimize the characteristics of drug release from poly-(lactide-co-glycolide) (PLGA) copolymer biodegradable microspheres. A modified solvent evaporation and double emulsion technique was used to prepare the microspheres. Release kinetic studies were carried out in silanized tubes and dialysis bags, whereby microspheres were suspended and incubated in phosphate buffered saline, sampled at fixed intervals, and analyzed for drug content using a modified Lowry protein assay procedure. An initial burst was observed whereby about 50% of the total dose of the drug was released from the microspheres within 24 hr and 75% within 3 days. This was followed by a period of slow release over a period of 3 weeks in which another 10-15% of drug was released. Drug release from the dialysis bags was more gradual, and 50% CT was released only after 4 days and 75% after 12 days of release. Scanning electron micrographs revealed spherical particles with channel-like structures and a porous surface after being suspended in an aqueous solution for 5 days. Differential scanning calorimetric studies revealed that CT was present as a mix of amorphous and crystalline forms within the microspheres. Overall, these studies demonstrated that sustained release of CT from PLGA microspheres over a 3-week period is feasible and that release of drug from dialysis bags was more predictable than from tubes.

  2. Effect of PEGylation on stability of peptide in poly(lactide-co-glycolide) microspheres.

    PubMed

    Park, Eun Ji; Tak, Tae Hyuk; Na, Dong Hee; Lee, Kang Choon

    2010-07-01

    The purpose of this study was to evaluate the effect of PEGylation on the stabilization of peptide in poly(D,L-lactide-co-glycolide) (PLGA) microspheres for sustained release delivery. As model peptide, growth hormone-releasing peptide-6 (GHRP-6) was conjugated with succinimidyl propionate monomethoxy poly(ethylene glycol) (PEG) with an average molecular weight of 2000 Da. The mono-PEG-GHRP-6 was separated by ion-exchange chromatography, and its molecular mass was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The microspheres encapsulating native GHRP-6 or mono-PEG-GHRP-6 were prepared using the single oil-in-water emulsion solvent evaporation method. During incubation in a 0.1 M phosphate buffer (pH 7.4) for one month at 37 degrees C, native GHRP-6 microspheres were identified to form several acylated peptides by reversed-phase HPLC and MALDI-TOF MS, whereas the mono-PEG-GHRP-6 microspheres was not affected from peptide acylation by PLGA. This study demonstrates that PEGylation can stabilize peptide against the acylation reaction occurred in PLGA microspheres.

  3. Coaxial electrohydrodynamic atomization process for production of polymeric composite microspheres

    PubMed Central

    Xu, Qingxing; Qin, Hao; Yin, Zhenyuan; Hua, Jinsong; Pack, Daniel W.; Wang, Chi-Hwa

    2013-01-01

    Polymeric composite microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(D,L-lactic acid) (PDLLA) shell layer were successfully fabricated by coaxial electrohydrodynamic atomization (CEHDA) process. Process conditions, including nozzle voltage and polymer solution flow rates, as well as solution parameters, such as polymer concentrations, were investigated to ensure the formation of composite microspheres with a doxorubicin-loaded PLGA core surrounded by a relatively drug-free PDLLA shell layer. Various microsphere formulations were fabricated and characterized in terms of their drug distribution, encapsulation efficiency and in vitro release. Numerical simulation of CEHDA process was performed based on a computational fluid dynamics (CFD) model in Fluent by employing the process conditions and fluid properties used in the experiments. The simulation results were compared with the experimental work to illustrate the capability of the CFD model to predict the production of consistent compound droplets, and hence, the expected core-shell structured microspheres. PMID:24347672

  4. Coaxial electrohydrodynamic atomization process for production of polymeric composite microspheres.

    PubMed

    Xu, Qingxing; Qin, Hao; Yin, Zhenyuan; Hua, Jinsong; Pack, Daniel W; Wang, Chi-Hwa

    2013-12-18

    Polymeric composite microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(D,L-lactic acid) (PDLLA) shell layer were successfully fabricated by coaxial electrohydrodynamic atomization (CEHDA) process. Process conditions, including nozzle voltage and polymer solution flow rates, as well as solution parameters, such as polymer concentrations, were investigated to ensure the formation of composite microspheres with a doxorubicin-loaded PLGA core surrounded by a relatively drug-free PDLLA shell layer. Various microsphere formulations were fabricated and characterized in terms of their drug distribution, encapsulation efficiency and in vitro release. Numerical simulation of CEHDA process was performed based on a computational fluid dynamics (CFD) model in Fluent by employing the process conditions and fluid properties used in the experiments. The simulation results were compared with the experimental work to illustrate the capability of the CFD model to predict the production of consistent compound droplets, and hence, the expected core-shell structured microspheres.

  5. Assessment of PLGA-PEG-PLGA copolymer hydrogel for sustained drug delivery in the ear.

    PubMed

    Feng, Liang; Ward, Jonette A; Li, S Kevin; Tolia, Gaurav; Hao, Jinsong; Choo, Daniel I

    2014-01-01

    Temperature sensitive copolymer systems were previously studied using modified diffusion cells in vitro for intratympanic injection, and the PLGA-PEG-PLGA copolymer systems were found to provide sustained drug delivery for several days. The objectives of the present study were to assess the safety of PLGA-PEG-PLGA copolymers in intratympanic injection in guinea pigs in vivo and to determine the effects of additives glycerol and poloxamer in PLGA-PEGPLGA upon drug release in the diffusion cells in vitro for sustained inner ear drug delivery. In the experiments, the safety of PLGA-PEG-PLGA copolymers to inner ear was evaluated using auditory brainstem response (ABR). The effects of the additives upon drug release from PLGA-PEG-PLGA hydrogel were investigated in the modified Franz diffusion cells in vitro with cidofovir as the model drug. The phase transition temperatures of the PLGA-PEG-PLGA copolymers in the presence of the additives were also determined. In the ABR safety study, the PLGA-PEG-PLGA copolymer alone did not affect hearing when delivered at 0.05-mL dose but caused hearing loss after 0.1-mL injection. In the drug release study, the incorporation of the bioadhesive additive, poloxamer, in the PLGA-PEG-PLGA formulations was found to decrease the rate of drug release whereas the increase in the concentration of the humectant additive, glycerol, provided the opposite effect. In summary, the PLGA-PEG-PLGA copolymer did not show toxicity to the inner ear at the 0.05-mL dose and could provide sustained release that could be controlled by using the additives for inner ear applications.

  6. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, R.M.

    A method and apparatus is disclosed for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  7. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, Russell M.

    1980-01-01

    A method and apparatus for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated to relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  8. Hybrid microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1985-01-01

    Substrates, particularly inert synthetic organic resin beads (10) or sheet (12) such as polystyrene are coated with a covalently bound layer (24) of polyacrolein by irradiation a solution (14) of acrolein or other aldehyde with high intensity radiation. Individual microspheres (22) are formed which attach to the surface to form the aldehyde containing layer (24). The aldehyde groups can be converted to other functional groups by reaction with materials such as hydroxylamine. Adducts of proteins such as antibodies or enzymes can be formed by direct reaction with the surface aldehyde groups.

  9. Microsphere priming facilitates induction of potent therapeutic T-cell immune responses against autochthonous liver cancers.

    PubMed

    Brinkhoff, Benjamin; Ostroumov, Dmitrij; Heemcke, Jessica; Woller, Norman; Gürlevik, Engin; Manns, Michael P; Longerich, Thomas; Zender, Lars; Harty, John T; Kubicka, Stefan; Kühnel, Florian; Wirth, Thomas C

    2014-04-01

    Immunotherapy of solid tumors is often hampered by the low frequency of tumor-specific T cells elicited by current vaccination strategies. Here, we describe a prime-boost vaccination protocol based on the administration of antigen conjugated to poly-lactic-co-glycolic acid (PLGA) microspheres followed by booster vaccination with Listeria monocytogenes vectors, which rapidly generates potent immune responses within two weeks. Compared with conventional vaccination with antigen-pulsed dendritic cells, the use of PLGA microspheres resulted in immune responses of significantly higher magnitude, which could be further enhanced via coinjection of TLR 3 agonists. In an immunocompetent model of subcutaneous hepatocellular carcinoma, PLGA/Listeria vaccination resulted in complete remission of established tumors and prolonged survival. To further test the efficacy of the novel vaccination for the treatment of solid tumors, we developed an orthotopic liver cancer model based on the injection of transposon-flanked plasmids expressing oncogenes and model antigens. In this transgenic mouse model of liver cancer, PLGA/Listeria vaccination resulted in eradication of liver tumors, long-term survival of animals and establishment of stable cancer-specific memory CD8(+) T-cell populations. Therefore, combined PLGA/Listeria vaccination holds promise as a novel immunotherapeutic option for the treatment of solid cancers and as a means to boost the therapeutic efficacy of established cancer vaccines.

  10. Reconstructing jaw defects with MSCs and PLGA-encapsulated growth factors

    PubMed Central

    Tee, Boon Ching; Desai, Kashappa Goud H; Kennedy, Kelly S; Sonnichsen, Brittany; Kim, Do-Gyoon; Fields, Henry W; Mallery, Susan R; Schwendeman, Steven P; Sun, Zongyang

    2016-01-01

    Cell and growth factor-based tissue engineering has shown great potentials for skeletal regeneration. This study tested its feasibility in reconstructing large mandibular defects and compared the efficacy of varied construction materials and sealing methods. Bilateral mandibular critical-size (5-cm3) defects were created on six 4-month-old domestic pigs, and grafted with β-tricalcium phosphate (βTCP) only (Group-A), βTCP with autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) (Group-B), and βTCP with BM-MSCs and biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres containing bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) (Group-C). The buccal sides of Groups-B/-C were either sealed by fibrin sealant or by a biodegradable PLGA barrier membrane before soft-tissue closure. Computed tomography (CT), microCT and histology analyses were performed 12 weeks postoperatively. In vitro data demonstrated that BM-MSCs, with MSC properties confirmed, remained vital after integration with βTCP; and PLGA microspheres exhibited an initial burst followed by slow and continuous release of growth factors over a period of 28 days. In vivo data demonstrated that Group-B/-C sites had significantly greater gap obliteration, higher tissue mineral densities and more residual βTCP granules (p<0.05, Kruskal-Wallis tests). Qualitatively, Group-B/-C defect sites had started remodeling while Group-A sites were mainly forming new bone to bridge the gaps. Furthermore, βTCP degradation was not mediated by macrophages or osteoclasts, and was significantly slowed down by sealing the defects with barrier membrane. Combined, these data present a promising formulation composed of βTCP granules, autologous MSCs, controlled-release growth factors and biodegradable PLGA barrier membrane for the reconstruction of critical-size mandibular defects. PMID:27398152

  11. Pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  12. Application of Raman microscopy to biodegradable double-walled microspheres.

    PubMed

    Widjaja, Effendi; Lee, Wei Li; Loo, Say Chye Joachim

    2010-02-15

    Raman mapping measurements were performed on the cross section of the ternary-phase biodegradable double-walled microsphere (DWMS) of poly(D,L-lactide-co-glycolide) (50:50) (PLGA), poly(L-lactide) (PLLA), and poly(epsilon-caprolactone) (PCL), which was fabricated by a one-step solvent evaporation method. The collected Raman spectra were subjected to a band-target entropy minimization (BTEM) algorithm in order to reconstruct the pure component spectra of the species observed in this sample. Seven pure component spectral estimates were recovered, and their spatial distributions within DWMS were determined. The first three spectral estimates were identified as PLLA, PLGA 50:50, and PCL, which were the main components in DWMS. The last four spectral estimates were identified as semicrystalline polyglycolic acid (PGA), dichloromethane (DCM), copper-phthalocyanine blue, and calcite, which were the minor components in DWMS. PGA was the decomposition product of PLGA. DCM was the solvent used in DWMS fabrication. Copper-phthalocyanine blue and calcite were the unexpected contaminants. The current result showed that combined Raman microscopy and BTEM analysis can provide a sensitive characterization tool to DWMS, as it can give more specific information on the chemical species present as well as the spatial distributions. This novel analytical method for microsphere characterization can serve as a complementary tool to other more established analytical techniques, such as scanning electron microscopy and optical microscopy.

  13. Synergistic Effect of Mesoporous Silica and Hydroxyapatite in Loaded Poly(DL-lactic-co-glycolic acid) Microspheres on the Regeneration of Bone Defects

    PubMed Central

    Lin, Kai-Feng; Fan, Jun-Jun; Hu, Gang; Dong, Xin; Zhao, Yi-Nan; Song, Yue; Guo, Zhong-Shang

    2016-01-01

    A microsphere composite made of poly(DL-lactic-co-glycolic acid) (PLGA), mesoporous silica nanoparticle (MSN), and nanohydroxyapatite (nHA) (PLGA-MSN/nHA) was prepared and evaluated as bone tissue engineering materials. The objective of this study was to investigate the synergistic effect of MSN/nHA on biocompatibility as well as its potential ability for bone formation. First, we found that this PLGA-MSN/nHA composite performed good characteristics on microstructure, mechanical strength, and wettability. By cell culture experiments, the adhesion and proliferation rate of the cells seeded on PLGA-MSN/nHA composite was higher than those of the controls and high levels of osteogenetic factors such as ALP and Runx-2 were detected by reverse transcriptase polymerase chain reaction. Finally, this PLGA-MSN/nHA composite was implanted into the femur bone defect in a rabbit model, and its ability to induce bone regeneration was observed by histological examinations. Twelve weeks after implantation, the bone defects had significantly more formation of mature bone and less residual materials than in the controls. These results demonstrate that this PLGA-MSN/nHA composite, introducing both MSN and nHA into PLGA microspheres, can improve the biocompatibility and osteoinductivity of composite in vitro and in vivo and had potential application in bone regeneration. PMID:27652269

  14. Synergistic Effect of Mesoporous Silica and Hydroxyapatite in Loaded Poly(DL-lactic-co-glycolic acid) Microspheres on the Regeneration of Bone Defects.

    PubMed

    He, Shu; Lin, Kai-Feng; Fan, Jun-Jun; Hu, Gang; Dong, Xin; Zhao, Yi-Nan; Song, Yue; Guo, Zhong-Shang; Bi, Long; Liu, Jian

    2016-01-01

    A microsphere composite made of poly(DL-lactic-co-glycolic acid) (PLGA), mesoporous silica nanoparticle (MSN), and nanohydroxyapatite (nHA) (PLGA-MSN/nHA) was prepared and evaluated as bone tissue engineering materials. The objective of this study was to investigate the synergistic effect of MSN/nHA on biocompatibility as well as its potential ability for bone formation. First, we found that this PLGA-MSN/nHA composite performed good characteristics on microstructure, mechanical strength, and wettability. By cell culture experiments, the adhesion and proliferation rate of the cells seeded on PLGA-MSN/nHA composite was higher than those of the controls and high levels of osteogenetic factors such as ALP and Runx-2 were detected by reverse transcriptase polymerase chain reaction. Finally, this PLGA-MSN/nHA composite was implanted into the femur bone defect in a rabbit model, and its ability to induce bone regeneration was observed by histological examinations. Twelve weeks after implantation, the bone defects had significantly more formation of mature bone and less residual materials than in the controls. These results demonstrate that this PLGA-MSN/nHA composite, introducing both MSN and nHA into PLGA microspheres, can improve the biocompatibility and osteoinductivity of composite in vitro and in vivo and had potential application in bone regeneration.

  15. New second-generation long-acting injectable antipsychotics for the treatment of schizophrenia.

    PubMed

    Citrome, Leslie

    2013-07-01

    Long-acting injectable (depot) antipsychotics are one approach in the management of individuals with schizophrenia. Since the introduction of risperidone long-acting injection in 2003, three additional second-generation antipsychotics have become available in a long-acting injectable formulation: paliperidone, olanzapine and aripiprazole. Although these different depot options can help with adherence and thus encourage better treatment outcomes, they differ in terms of specific indications, approved injection sites, needle gauge, injection volume, injection interval, requirements for oral supplementation, availability of prefilled syringes, storage needs and postinjection observation period, as well as potential drug-drug interactions and commonly encountered adverse reactions. After a review of the evidence base, guidance is offered on the appropriate selection among the long-acting injectable formulations of both first and second-generation antipsychotics.

  16. [A long-acting second generation anti-psychotic--experience in Israel].

    PubMed

    Stein-Reisner, Orit; Preisman, Olga; Alfici, Susana; Melamed, Yuval; Bleich, Avi

    2004-06-01

    Schizophrenia is a chronic disease characterized by psychotic symptoms as well as negative symptoms such as affective flattening, social withdrawal and occupational dysfunction. Anti-psychotic medications reduce the risk of psychotic exacerbations and hospitalization. Poor compliance is common among patients with schizophrenia. Long-acting medications have such advantages as stabilizing drug levels and improving compliance. Second generation anti-psychotic medications were found to be more effective and tolerable compared to first generation drugs. These medications cause less extra-pyramidal symptoms, and compliance with them was shown to be better. Until recently there were only first generation long-acting anti-psychotics in use. Recently a new second generation long-acting anti-psychotic drug was introduced in Israel. We present our experience with a first schizophrenic patient treated with long-acting Risperidone (Risperdal Consta). The patient was treated in the past with several first generation anti-psychotics and suffered severe extra-pyramidal symptoms. His compliance with treatment was poor. Under treatment with oral Risperidone a considerable improvement was recorded, however compliance remained poor. Under treatment with long-acting Risperidone, Intramuscularly 25 Mg every two week, both positive and negative symptoms improved substantially, as well as compliance with treatment. The results of this case study encourage us to believe that many more patients will benefit from the advantages of both a second-generation anti-psychotic and a long-acting preparation.

  17. microsphere assemblies

    NASA Astrophysics Data System (ADS)

    Peña-Flores, Jesús I.; Palomec-Garfias, Abraham F.; Márquez-Beltrán, César; Sánchez-Mora, Enrique; Gómez-Barojas, Estela; Pérez-Rodríguez, Felipe

    2014-09-01

    The effect of Fe ion concentration on the morphological, structural, and optical properties of TiO2 films supported on silica (SiO2) opals has been studied. TiO2:Fe2O3 films were prepared by the sol-gel method in combination with a vertical dip coating procedure; precursor solutions of Ti and Fe were deposited on a monolayer of SiO2 opals previously deposited on a glass substrate by the same procedure. After the dip coating process has been carried out, the samples were thermally treated to obtain the TiO2:Fe2O3/SiO2 composites at the Fe ion concentrations of 1, 3, and 5 wt%. Scanning electron microscopy (SEM) micrographs show the formation of colloidal silica microspheres of about 50 nm diameter autoensembled in a hexagonal close-packed fashion. Although the X-ray diffractograms show no significant effect of Fe ion concentration on the crystal structure of TiO2, the μ-Raman and reflectance spectra do show that the intensity of a phonon vibration mode and the energy bandgap of TiO2 decrease as the Fe+3 ion concentration increases.

  18. Formulation and characterization of microspheres loaded with imatinib for sustained delivery.

    PubMed

    Ramazani, F; Chen, W; Van Nostrum, C F; Storm, G; Kiessling, F; Lammers, T; Hennink, W E; Kok, R J

    2015-03-30

    The aim of this study was the development of imatinib-loaded poly(d,l-lactide-co-glycolide) (PLGA) microspheres with high loading efficiency which can afford continuous release of imatinib over a prolonged period of time. Imatinib mesylate loaded PLGA microspheres with a size of 6-20 μm were prepared by a double emulsion (W1/O/W2) method using dichloromethane as volatile solvent. It was found that the microspheres were spherical with a non-porous surface; imatinib loading efficiency (LE) was highly dependent on the pH of the external water phase (W2). By increasing the pH of W2 phase above the highest pKa of imatinib (pKa 8.1), at which imatinib is mainly uncharged, the LE increased from 10% to 90% (pH 5.0 versus pH 9.0). Conversely, only 4% of its counter ion, mesylate, was retained in the microspheres at the same condition (pH 9.0). Since mesylate is highly water soluble, it is unlikely that it partitions into the organic phase. We demonstrated, using differential scanning calorimetry (DSC), that imatinib was molecularly dispersed in the polymeric matrix at loadings up to 8.0%. At higher drug loading, imatinib partially crystallized in the matrix. Imatinib microspheres released their cargo during three months by a combination of diffusion through the polymer matrix and polymer erosion. In conclusion, we have formulated imatinib microspheres with high LE and LC. Although we started with a double emulsion of imatinib mesylate, the obtained microspheres contained imatinib base which was mainly molecularly dispersed in the polymer matrix. These microspheres release imatinib over a 3-month period which is of interest for local treatment of cancer.

  19. Development of Recombinant Human Growth Hormone (rhGH) sustained-release microspheres by a low temperature aqueous phase/aqueous phase emulsion method.

    PubMed

    Kang, Jian; Wu, Fei; Cai, Yunpeng; Xu, Mingxin; He, Mu; Yuan, Weien

    2014-10-01

    A novel method has been developed to protect Recombinant Human Growth Hormone (rhGH) in poly (lactic-co-glycolic acid) (PLGA) microspheres using an aqueous phase/aqueous phase emulsion and S/O/W multi-emulsion method. This method develops a novel rhGH sustained-release system, which is based on the combination of rhGH-loaded dextran microparticles and PLGA microspheres. The process to fabricate rhGH-loaded dextran microparticles involves an aqueous phase/aqueous phase emulsion system formed at the reduced temperature. RhGH was first dissolved in water together with dextran and polyethylene glycol, followed by stirring at the speed of 2000 rpm for 20-30s at 0°C, and then a freezing process could enable the dextran phase to separate from the continuous PEG phase and rhGH could preferentially be loaded with dextran. The sample after freezing and phase separation was then lyophilized to powder and washed with dichloromethane to remove the PEG. Once loaded in the dextran microparticles (1-4 μm in diameter), rhGH gained resistance to interface tensions and was encapsulated into PLGA microspheres without aggregation thereafter. RhGH released from PLGA microspheres was in a sustained manner with minimal burst and maximally reduced incomplete release in vitro. Single subcutaneous injection of rhGH-loaded PLGA microspheres to rats resulted in a stable plasma concentration for 30 days avoiding the drug concentration fluctuations after multiple injections of protein solutions. In a hypophysectomized rat model, the IGF-1 and bodyweight results showed that there were higher than the levels obtained for the sustained release formulation by W/O/W for 40 days. These results suggest that the microsphere delivery system had the potential to be an injectable depot for sustained-release of the biocompatible protein of rhGH.

  20. Biodegradable poly(lactic-co-glycolic acid) microspheres loaded with S-nitroso-N-acetyl-D-penicillamine for controlled nitric oxide delivery.

    PubMed

    Lautner, Gergely; Meyerhoff, Mark E; Schwendeman, Steven P

    2016-03-10

    Nitric oxide (NO) is a fascinating and important endogenous free-radical gas with potent antimicrobial, vasodilating, smooth muscle relaxant, and growth factor stimulating effects. However, its wider biomedical applicability is hindered by its cumbersome administration, since NO is unstable especially in biological environments. In this work, to ultimately develop site-specific controlled release vehicles for NO, the NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) was encapsulated within poly(lactic-co-glycolic acid) 50:50 (PLGA) microspheres by using a solid-in-oil-in-water emulsion solvent evaporation method. The highest payload was 0.56(±0.01) μmol SNAP/mg microspheres. The in vitro release kinetics of the donor were controlled by the bioerosion of the PLGA microspheres. By using an uncapped PLGA (Mw=24,000-38,000) SNAP was slowly released for over 10days, whereas by using the ester capped PLGA (Mw=38,000-54,000) the release lasted for over 4weeks. The presence of copper ions and/or ascorbate in solution was necessary to efficiently decompose the released NO donor and obtain sustained NO release. It was also demonstrated that light can be used to induce rapid NO release from the microspheres over several hours. SNAP exhibited excellent storage stability when encapsulated in the PLGA microspheres. These new microsphere formulations may be useful for site-specific administration and treatment of pathologies associated with dysfunction in endogenous NO production, e.g. treatment of diabetic wounds, or in diseases involving other biological functions of NO including vasodilation, antimicrobial, anticancer, and neurotransmission.

  1. Cationic poly(lactic-co-glycolic acid) iron oxide microspheres for nucleic acid detection

    NASA Astrophysics Data System (ADS)

    Pandey, Chandra Mouli; Sharma, Aditya; Sumana, Gajjala; Tiwari, Ida; Malhotra, Bansi Dhar

    2013-04-01

    Herein, we envisage the possibility of preparing stable cationic poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating the iron oxide nanoparticles (IONPs; 8-12 nm). The IONPs are incorporated into PLGA in organic phase followed by microsphere formation and chitosan coating in aqueous medium via nano-emulsion technique. The average size of the microspheres, as determined by dynamic light scattering are about 310 nm, while the zeta potential for the composite remains near 35 mV at pH 4.0. These microspheres are electrophoretically deposited onto indium tin oxide (ITO)-coated glass substrate used as cathode and parallel platinum plate as the counter electrode. This platform is utilized to fabricate a DNA biosensor, by immobilizing a probe sequence specific to Escherichia coli. The bioelectrode shows a surface-controlled electrode reaction with the electron transfer coefficient (α) of 0.64 and charge transfer rate constant (ks) of 61.73 s-1. Under the optimal conditions, this biosensor shows a detection limit of 8.7 × 10-14 M and is found to retain about 81% of the initial activity after 9 cycles of use.Herein, we envisage the possibility of preparing stable cationic poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating the iron oxide nanoparticles (IONPs; 8-12 nm). The IONPs are incorporated into PLGA in organic phase followed by microsphere formation and chitosan coating in aqueous medium via nano-emulsion technique. The average size of the microspheres, as determined by dynamic light scattering are about 310 nm, while the zeta potential for the composite remains near 35 mV at pH 4.0. These microspheres are electrophoretically deposited onto indium tin oxide (ITO)-coated glass substrate used as cathode and parallel platinum plate as the counter electrode. This platform is utilized to fabricate a DNA biosensor, by immobilizing a probe sequence specific to Escherichia coli. The bioelectrode shows a surface-controlled electrode reaction with the

  2. Comparison of Subjective Experiences and Effectiveness of First-Generation Long-Acting Injectable Antipsychotics and Risperidone Long-Acting Injectables in Patients With Schizophrenia.

    PubMed

    Chen, Wen-Yin; Lin, Shih-Ku

    2016-10-01

    We conducted a cross-sectional study to compare the subjective experiences and clinical effects of first-generation long-acting injectable (FGA-LAI) antipsychotics with those of risperidone long-acting injectables (RIS-LAIs) in 434 schizophrenia patients. Compared with the RIS-LAI group, the patients treated with FGA-LAIs had a significantly longer duration of illness and LAI treatment and were older. Our results suggest that patients treated with FGA-LAI have more satisfactory subjective experiences compared with patients treated with RIS-LAI and that both FGA-LAI and RIS-LAI treatments can prevent relapses and hospitalization. Additional longitudinal studies determining the long-term benefits of RIS-LAI are warranted.

  3. Long-acting injectable risperidone in partially adherent and nonadherent patients with schizophrenia

    PubMed Central

    Louzã, Mário Rodrigues; Elkis, Helio; Ruschel, Sandra; de Oliveira, Irismar Reis; Bressan, Rodrigo Affonseca; Belmonte-de-Abreu, Paulo; Grabowski, Hamilton; Appolinário, José Carlos

    2011-01-01

    Background: Long-acting injectable antipsychotics may improve medication adherence, thereby improving overall treatment effectiveness. This study aimed to evaluate the effectiveness, safety, and tolerability of risperidone long-acting injection in schizophrenic patients switched from oral antipsychotic medication. Methods: In a 12-month, multicenter, open-label, noncomparative study, symptomatically stable patients on oral antipsychotic medication with poor treatment adherence during the previous 12 months received intramuscular injections of risperidone long-acting injection (25 mg starting dose) every 2 weeks. The primary endpoint was the change in Positive and Negative Syndrome Scale (PANSS) total score. Results: Of the 60 patients who were screened, 53 received at least one injection (safety population), and 51 provided at least one postbaseline assessment. Mean PANSS total scores improved significantly throughout the study and at endpoint. Significant improvements were also observed in Clinical Global Impression of Severity, Personal and Social Performance, and Drug Attitude Inventory scales. Risperidone long-acting injection was safe and well-tolerated. Severity of movement disorders on the Extrapyramidal Symptom Rating Scale was reduced significantly. The most frequently reported adverse events were insomnia (22.6%), increased prolactin (17.0%), and weight gain (13.2%). Conclusion: Risperidone long-acting injection was associated with significant symptomatic improvements in stable patients with schizophrenia following a switch from previous antipsychotic medications. PMID:21822391

  4. Long-acting injectable risperidone: safety and efficacy in stable patients switched from conventional depot antipsychotics.

    PubMed

    Turner, Martin; Eerdekens, Els; Jacko, Mary; Eerdekens, Mariëlle

    2004-07-01

    Long-acting injectable risperidone was assessed in schizophrenia patients who were symptomatically stable on conventional depot antipsychotics and who were then switched to long-acting risperidone. Participants in this open-label, multicentre, 12-week trial had received flupenthixol decanoate, fluphenazine decanoate, haloperidol decanoate, or zuclopenthixol decanoate for 4 months or longer. Each was considered symptomatically stable by investigators. After receiving two cycles of their conventional depot antipsychotic during the run-in period, patients were switched to receive long-acting risperidone every 2 weeks for 12 weeks at an initial dose of 25 mg. This dose could be increased in 12.5-mg increments at 4-week intervals. Ninety-two percent of the patients received all six injections; 62% received the 25-mg dose throughout the treatment period. Adverse events related to movement disorders were reported in 3%. Severity of movement disorders decreased during long-acting risperidone treatment. Positive and Negative Syndrome Scale (PANSS) total and factor scores and scores on the Clinical Global Impressions severity scale were significantly reduced during treatment; 48% of these stable patients showed further symptom improvement (> or =20% decrease in PANSS score at endpoint). The results indicate that patients with schizophrenia who are symptomatically stable during treatment with a conventional depot antipsychotic can be safely and effectively switched to long-acting injectable risperidone without a prior transition to oral risperidone.

  5. Amlodipine as an antiischemic drug is superior to long acting nitrates

    PubMed Central

    Koraćević, Goran P.; Veličković-Radovanović, Radmila M.; Apostolović, Svetlana R.; Krstić, Nebojša H.; Tasić, Ivan S.; Zdravković, Marija D.; Antonijević, Nebojša M.; Damnjanović, Goran N.; Kostić, Tomislav L.

    2015-01-01

    European Society of Cardiology Guidelines cite results of meta-analysis that the use of calcium channel blockers results in fewer angina episodes per week vs. long-acting nitrates. Moreover, we listed 12 reasons more to prefer amlodipine over long-acting nitrates, especially in stable angina pectoris patients with arterial hypertension. It may be the way to decrease polypharmacy without loosing efficacy. Some important advantages of amlodipine versus long-acting nitrate(s) are: amlodipine also treats hypertension, it helps reducing hypertensive target organ damages (e.g. left ventricular hypertrophy) and prevents morning blood pressure surge. Moreover, amlodipine can be given once daily (which improves adherence), it produces neither tolerance nor rebound, it has less side effects. PMID:28352677

  6. Use of hydrodynamic flow focusing for the generation of biodegradable camptothecin-loaded polymer microspheres.

    PubMed

    Schneider, Thomas; Zhao, Hong; Jackson, John K; Chapman, Glenn H; Dykes, James; Häfeli, Urs O

    2008-11-01

    The present study was conducted to investigate the use of hydrodynamic flow focusing for the generation of biodegradable polymer microspheres encapsulating the anticancer drug camptothecin. Poly(D,L-lactide-co-glycolide) (PLGA) and poly(L-lactide) (PLA) were used as the matrix materials. Camptothecin was dissolved in the disperse phase and microspheres with a mean size between 2 and 3 microm generated using hydrodynamic flow focusing. When up to 1 wt.% of the drug was added to PLA, the drug encapsulation efficiency was 64%. For PLGA, the drug encapsulation efficiency was between 39 and 46%. Drug release from PLA particles was rapid and complete within 6 h, while drug release from PLGA particles showed no burst effect and followed a first order release profile. The encapsulated camptothecin stayed in its active lactone form, as shown by HPLC, and was able to exert cell toxic effects as shown by a cell viability assay. Hydrodynamic flow focusing is a promising tool for the preparation of drug-releasing biodegradable microspheres typically made by solvent evaporation and/or solvent extraction, as indicated by the successful encapsulation of the anticancer drug camptothecin.

  7. Effectiveness of long-acting injectable antipsychotics in delusional disorders with nonprominent hallucinations and without hallucinations.

    PubMed

    González-Rodríguez, Alexandre; Molina-Andreu, Oriol; Penadés, Rafael; Bernardo, Miquel; Catalán, Rosa

    2014-05-01

    The presence of nonprominent hallucinations in delusional disorder (DD) has been accepted by the current Diagnostic and Statistical Manual of Mental Disorders, 5th ed. A recent meta-analysis revealed that patients with schizophrenia treated with long-acting atypical antipsychotics showed a significant improvement in psychotic symptoms. However, little research has been conducted on DD. Our goal was to investigate demographic and clinical differences between two subgroups of DD patients, those with nonprominent hallucinations and those without hallucinations, and to determine treatment effectiveness of long-acting antipsychotics in these patients. We conducted a longitudinal observational study with a 6-month follow-up period in a clinical group of 45 DD outpatients. Positive and Negative Syndrome Scale (PANSS), Personal and Social Performance Scale, and Hamilton Rating Scale for Depression-17 (HRSD-17) were used for assessment. Age at onset of DD, scores in baseline assessment scales, and drug compliance were included in the analysis as potential confounders. When uncorrected for influencing factors, patients treated with long-acting antipsychotics showed lower scores in PANSS positive and negative subscales. There were no statistically significant clinical subgroup×treatment group interactions for any of the scores in assessment scales at 6 months. After adjustment, patients treated with long-acting antipsychotics showed lower scores in the PANSS negative subscale and a tendency toward improvement in scores in the PANSS positive subscale. Our study suggests that risperidone long-acting injection and paliperidone palmitate long-acting injection may be useful in the treatment of DD patients, specifically those with nonprominent hallucinations.

  8. Angiogenic microspheres promote neural regeneration and motor function recovery after spinal cord injury in rats

    PubMed Central

    Yu, Shukui; Yao, Shenglian; Wen, Yujun; Wang, Ying; Wang, Hao; Xu, Qunyuan

    2016-01-01

    This study examined sustained co-delivery of vascular endothelial growth factor (VEGF), angiopoietin-1 and basic fibroblast growth factor (bFGF) encapsulated in angiogenic microspheres. These spheres were delivered to sites of spinal cord contusion injury in rats, and their ability to induce vessel formation, neural regeneration and improve hindlimb motor function was assessed. At 2–8 weeks after spinal cord injury, ELISA-determined levels of VEGF, angiopoietin-1, and bFGF were significantly higher in spinal cord tissues in rats that received angiogenic microspheres than in those that received empty microspheres. Sites of injury in animals that received angiogenic microspheres also contained greater numbers of isolectin B4-binding vessels and cells positive for nestin or β III-tubulin (P < 0.01), significantly more NF-positive and serotonergic fibers, and more MBP-positive mature oligodendrocytes. Animals receiving angiogenic microspheres also suffered significantly less loss of white matter volume. At 10 weeks after injury, open field tests showed that animals that received angiogenic microspheres scored significantly higher on the Basso-Beattie-Bresnahan scale than control animals (P < 0.01). Our results suggest that biodegradable, biocompatible PLGA microspheres can release angiogenic factors in a sustained fashion into sites of spinal cord injury and markedly stimulate angiogenesis and neurogenesis, accelerating recovery of neurologic function. PMID:27641997

  9. Prolonged inhibition of inflammation in osteoarthritis by triamcinolone acetonide released from a polyester amide microsphere platform.

    PubMed

    Rudnik-Jansen, Imke; Colen, Sascha; Berard, Julien; Plomp, Saskia; Que, Ivo; van Rijen, Mattie; Woike, Nina; Egas, Annelies; van Osch, Gerjo; van Maarseveen, Erik; Messier, Ken; Chan, Alan; Thies, Jens; Creemers, Laura

    2017-03-09

    Controlled biomaterial-based corticosteroid release might circumvent multiple injections and the accompanying risks, such as hormone imbalance and muscle weakness, in osteoarthritic (OA) patients. For this purpose, microspheres were prepared from an amino acid-based polyester amide (PEA) platform and loaded with triamcinolone acetonide (TAA). TAA loaded microspheres were shown to release TAA for over 60days in PBS. Furthermore, the bioactivity lasted at least 28days, demonstrated by a 80-95% inhibition of PGE2 production using TNFα-stimulated chondrocyte culture, indicating inhibition of inflammation. Microspheres loaded with the near infrared marker NIR780-iodide injected in healthy rat joints or joints with mild collagenase-induced OA showed retention of the microspheres up till 70days after injection. After intra-articular injection of TAA-loaded microspheres, TAA was detectable in the serum until day seven. Synovial inflammation was significantly lower in OA joints injected with TAA-loaded microspheres based on histological Krenn scores. Injection of TAA-loaded nor empty microspheres had no effect on cartilage integrity as determined by Mankin scoring. In conclusion, the PEA platform shows safety and efficacy upon intra-articular injection, and its extended degradation and release profiles compared to the currently used PLGA platforms may render it a good alternative. Even though further in vivo studies may need to address dosing and readout parameters such as pain, no effect on cartilage pathology was found and inflammation was effectively lowered in OA joints.

  10. Use of Aripiprazole Long Acting Injection in Negative Symptoms of Schizophrenia

    PubMed Central

    James, Suneeta; Kapugama, Chaya; Al-Uzri, Mohammed

    2016-01-01

    Background. Evidence for the efficacious use of second-generation antipsychotics for the treatment of negative symptoms in schizophrenia is scant. Case Presentation. We report the case of a 34-year-old female of Afro-Caribbean origin, who presented with prominent negative symptoms of schizophrenia and was successfully treated with aripiprazole long acting injection. Within a period of six to nine months, the patient returned to her premorbid level of functioning. Conclusion. Aripiprazole long acting injection promises benefits in the treatment of negative symptoms of schizophrenia. Further research needs to be conducted on the use of this drug. PMID:26981301

  11. Differences in acute anorectic effects of long-acting GLP-1 receptor agonists in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-acting glucagon-like peptide-1 receptor (GLP-1R) agonists have both glucose- and weight-lowering effects. The brain is poised to mediate both of these actions since GLP-1Rs are present in key areas known to control weight and glucose. Although some research has been performed on the effects of ...

  12. Does Prolonged Therapy with a Long-Acting Stimulant Suppress Growth in Children with ADHD?

    ERIC Educational Resources Information Center

    Spencer, Thomas J.; Faraone, Stephen V.; Biederman, Joseph; Lerner, Marc; Cooper, Kimberly M.; Zimmerman, Brenda

    2006-01-01

    Objective: To investigate whether prolonged therapy with a long-acting stimulant affects growth in children with attention-deficit/hyperactivity disorder (ADHD). Method: One hundred seventy-eight children ages 6 to 13 years received OROS methylphenidate (OROS MPH, CONCERTA) for at least 21 months. Height and weight were measured monthly during the…

  13. Long-acting contraceptive agents: norethisterone esters of monoalkenyl and monoalkynyl acids.

    PubMed

    Francisco, C G; Freire, R; Hernandez, R; Salazar, J A; Suarez, E; García de la Mora, G A; Noguez, J A; Acosta, A; Jimeno, O

    1983-03-01

    The synthesis of nine new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described, with the esterifying acids bearing an acetylenic or olefinic function in a chain of eight or nine carbon atoms, for evaluation as long-acting contraceptive agents.

  14. Pharmacokinetics of Short- and Long-acting Formulations of Oxytetracycline After Intramuscular Administration in Chickens.

    PubMed

    Gberindyer, Aondover F; Okpeh, Ene R; Semaka, Asaaga A

    2015-12-01

    Both short- and long-acting formulations of oxytetracycline are commonly used in veterinary medicine to treat animals infected with gram-negative and gram-positive bacteria, rickettsiae, mycoplasma, and chlamydiae. To compare pharmacokinetics of short- and long-acting oxytetracycline in chickens, injectable formulations from the same pharmaceutical company were administered to healthy 6-week-old broiler chickens in accordance to the labeled instructions. Fourteen chickens were separated into 2 groups: chickens in group A (n = 7) were administered the short-acting formulation (10 mg/kg IM q24h) for 4 consecutive days, whereas those in group B (n = 7) were treated with a single dose (20 mg/kg IM) of the long-acting formulation. Blood samples were collected into heparinized tubes before and at 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 10, and 24 hours after initial treatment. Thereafter, blood samples were taken every 24 hours up to 120 hours. Plasma concentrations of oxytetracycline were determined by competitive enzyme-linked immunoabsorbent assay, and pharmacokinetic parameters were obtained. Both formulations delivered therapeutic plasma concentrations of oxytetracycline for approximately 100% of their respective dosing intervals as recommended. However, considering the additional labor, patient stress, and mortalities associated with handling, in addition to rejection of the carcass due to tissue necrosis resulting from multiple injections, we recommend use of the long-acting instead of the short-acting injectable formulation in broiler chickens.

  15. Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH). A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrino...

  16. Long-acting reversible contraceptives: intrauterine devices and the contraceptive implant.

    PubMed

    Espey, Eve; Ogburn, Tony

    2011-03-01

    The provision of effective contraception is fundamental to the practice of women's health care. The most effective methods of reversible contraception are the so-called long-acting reversible contraceptives, intrauterine devices and implants. These methods have multiple advantages over other reversible methods. Most importantly, once in place, they do not require maintenance and their duration of action is long, ranging from 3 to 10 years. Despite the advantages of long-acting reversible contraceptive methods, they are infrequently used in the United States. Short-acting methods, specifically oral contraceptives and condoms, are by far the most commonly used reversible methods. A shift from the use of short-acting methods to long-acting reversible contraceptive methods could help reduce the high rate of unintended pregnancy in the United States. In this review of long-acting reversible contraceptive methods, we discuss the intrauterine devices and the contraceptive implant available in the United States, and we describe candidates for each method, noncontraceptive benefits, and management of complications.

  17. Reversible inhibition of central precocious puberty with a long acting GnRH analogue.

    PubMed Central

    Ward, P S; Ward, I; McNinch, A W; Savage, D C

    1985-01-01

    A 7 year old girl with precocious puberty was treated with buserelin, a long acting analogue of gonadotrophin releasing hormone. Spontaneous and stimulated gonadotrophin secretion became prepubertal but returned to pubertal values when buserelin was withdrawn, suggesting that normal sexual maturation should follow cessation of treatment. PMID:3931565

  18. Treatment-completion rates with olanzapine long-acting injection versus risperidone long-acting injection in a 12-month, open-label treatment of schizophrenia: indirect, exploratory comparisons

    PubMed Central

    Ascher-Svanum, Haya; Montgomery, William S; McDonnell, David P; Coleman, Kristina A; Feldman, Peter D

    2012-01-01

    Background Little is known about the comparative effectiveness of atypical antipsychotics in long-acting injection formulation. Due to the absence of head-to-head studies comparing olanzapine long-acting injection and risperidone long-acting injection, this study was intended to make exploratory, indirect, cross-study comparisons between the long-acting formulations of these two atypical antipsychotics in their effectiveness in treating patients with schizophrenia. Methods Indirect, cross-study comparisons between olanzapine long-acting injection and risperidone long-acting injection used 12-month treatment-completion rates, because discontinuation of an antipsychotic for any cause is a recognized proxy measure of the medication’s effectiveness in treating schizophrenia. Following a systematic review of the literature, two indirect comparisons were conducted using open-label, single-cohort studies in which subjects were stabilized on an antipsychotic medication before depot initiation. The first analysis compared olanzapine long-acting injection (one study) with pooled data from nine identified risperidone long-acting injection studies. The second analysis was a “sensitivity analysis,” using only the most similar studies, one for olanzapine long-acting injection and one for risperidone long-acting injection, which shared near-identical study designs and involved study cohorts with near-identical patient characteristics. Pearson Chi-square tests assessed group differences on treatment-completion rates. Results Comparison of olanzapine long-acting injection data (931 patients) with the pooled data from the nine risperidone long-acting injection studies (3950 patients) provided almost identical 12-month treatment-completion rates (72.7% versus 72.4%; P = 0.87). When the two most similar studies were compared, the 12-month completion rate for olanzapine long-acting injection was significantly higher than for risperidone long-acting injection (81.3% versus 47

  19. Testing the effects of long-acting steroids in edema and ecchymosis after closed rhinoplasty

    PubMed Central

    Gutierrez, Santiago; Wuesthoff, Carolina

    2014-01-01

    BACKGROUND: Steroids have proven to be of some benefit in rhinoplasty edema and ecchymosis when administered at a high and repeated dose. OBJECTIVE: To evaluate the effects of single-dose, long-acting intramuscular steroids on postoperative edema and ecchymosis after closed rhinoplasty with osteotomies compared with placebo. METHODS: A randomized, double-blinded, placebo-controlled trial was performed. Fifty-four patients were randomly assigned to two groups: 28 received a single dose of long-acting dexamethasone (mean [± SD] dose 16±4 mg) immediately before anesthetic induction; the remaining 26 received an intramuscular injection of saline solution. The same surgeon performed all surgeries, with patients under general anesthesia. Acetaminophen was the only analgesic used to control postoperative pain. High-resolution digital photographs were taken on postoperative days 1, 3, 7 and 14. Scoring was performed separately for eyelid swelling and ecchymosis by an independent observer using a graded scale (0 to 5) for edema and a scoring system (0 to 13) for ecchymosis. RESULTS: No statistically significant differences in terms of age, sex or amount of bleeding during surgery were found between the two groups. No statistically significant difference was observed in the decrease of both ecchymosis and edema between placebo and high-dose, long-acting dexamethasone. A statistically significant difference in operation time was found, favouring the steroid group. No severe complications were observed due to steroid use. DISCUSSION: Osteotomies are basically a form of (controlled) trauma, with considerable disruption of the abundant blood vessels in this facial region and, therefore, are associated with with undesirable effects. A recent meta-analysis failed to show benefits of the use of steroids after postoperative day 3. Only a trend toward reduction in edema and ecchymosis with the use of long-acting steroids compared with placebo was demonstrated in the present study

  20. Deltoid Injections of Risperidone Long-acting Injectable in Patients with Schizophrenia

    PubMed Central

    Quiroz, Jorge A.; Rusch, Sarah; Thyssen, An; Kushner, Stuart

    2011-01-01

    Background Risperidone long-acting injectable was previously approved for treatment of schizophrenia as biweekly injections in the gluteal muscle only. We present data on local injection-site tolerability and safety of risperidone long-acting injectable and comparability of systemic exposure of deltoid versus gluteal injections. Methods Risperidone long-acting injectable was administered in an open-label, single-dose, two-way crossover study, with patients randomized to receive either 25mg gluteal/37.5mg deltoid crossover in two treatment periods or 50mg gluteal/50mg deltoid injections crossover; each treatment period was separated by an 85-day observation period (Study 1) and an open-label, multiple-dose study (4 sequential 37.5mg or 50mg deltoid injections every 2 weeks) (Study 2). The pharmacokinetic results from both the studies have already been published. Results In Study 1 (n=170), the majority of patients had no local injection-site findings, based on investigator and patient-rated evaluations. In Study 2 (n=53), seven of the 51 patients who received at least two deltoid injections discontinued (primary endpoint). However, none of the discontinuations were due to injection-site related reasons. The 90-percent upper confidence limit of the true proportion of injection-site issue withdrawals was 5.7 percent. No moderate or severe injection-site reactions were reported. Conclusion Intramuscular injections via the deltoid and gluteal sites are equivalent routes of administration of risperidone long-acting injectable with respect to local injection-site tolerability. The overall safety and tolerability profile of risperidone long-acting injectable was comparable when administered as an intramuscular injection in the deltoid (37.5mg and 50mg) and gluteal (25mg and 50mg) sites. PMID:21779538

  1. The role of tiotropium bromide, a long-acting anticholinergic bronchodilator, in the management of COPD.

    PubMed

    Saberi, Farzad; O'Donnell, Denis E

    2005-01-01

    Bronchodilator therapy forms the mainstay of treatment for symptomatic patients with COPD. Long-acting bronchodilators, which maintain sustained airway patency over a 24-hour period, represent an advance in therapy. Tiotropium bromide is a new long-acting inhaled anticholinergic agent with superior pharmacodynamic properties compared with the short-acting anticholinergic, ipratropium bromide. Tiotropium bromide has been consistently shown to have a greater impact than ipratropium bromide on clinically important outcome measures such as health status. The mechanisms of clinical benefit with tiotropium bromide are multifactorial, but improved airway function, which enhances lung emptying and allows sustained deflation of over-inflated lungs, appears to explain improvements in dyspnea and exercise endurance in COPD. Inhaled tiotropium bromide therapy has also been associated with reduction in acute exacerbations of COPD as well as reduced hospitalizations. The safety profile of tiotropium bromide is impressive: dry mouth is the most common adverse event and rarely necessitates termination of the drug. No tachyphylaxis to tiotropium bromide has been demonstrated in clinical trials lasting up to 1 year. There is preliminary information that the combination of long-acting anticholinergics and long-acting beta2-adrenoceptor agonists provides additive physiological and clinical benefits. According to recent international guidelines, long-acting bronchodilators should be considered early in the management of symptomatic patients with COPD in order to achieve effective symptom alleviation and reduction in activity limitation. Tiotropium bromide, because of its once-daily administration and its established efficacy and tolerability profile, has emerged as an attractive therapeutic option for this condition.

  2. Switching from risperidone long-acting injectable to paliperidone long-acting injectable or oral antipsychotics: analysis of a Medicaid claims database.

    PubMed

    Voss, Erica A; Ryan, Patrick B; Stang, Paul E; Hough, David; Alphs, Larry

    2015-05-01

    This report examines relapse risk following a switch from risperidone long-acting injectable (RLAI) to another long-acting injectable antipsychotic [paliperidone palmitate (PP)] versus a switch to oral antipsychotics (APs). Truven Health's MarketScan Multistate Medicaid Database compared relapses following switches from RLAI. New user cohorts for these two groups were created on the basis of first incidence of exposure to the 'switched to' drug. Groups were balanced using 1:1 propensity score matching. Time-to-event analysis assessed schizophrenia-related hospital/emergency department visits. A total of 188 patients switched from RLAI to PP, and 131 patients switched from RLAI to oral AP. Propensity score-matched cohort included 109 patients who switched to PP and 109 patients who switched to an oral AP. Patients who switched from RLAI to PP had fewer events (26 vs. 32), longer time to an event (mean 70 vs. 47 days), and lower risk of relapse (hazard ratio, 0.54; 95% confidence interval, 0.32-0.92; P=0.024) compared with those who switched from RLAI to oral AP. Switching from RLAI to PP may be associated with a lower risk for relapse and longer duration of therapy compared with switching to oral AP. Given the limitations of observational studies, these results should be confirmed by other prospective evaluations.

  3. A method to tune the shape of protein-encapsulated polymeric microspheres

    NASA Astrophysics Data System (ADS)

    Alteriis, Renato De; Vecchione, Raffaele; Attanasio, Chiara; Gregorio, Maria De; Porzio, Massimiliano; Battista, Edmondo; Netti, Paolo A.

    2015-07-01

    Protein encapsulation technologies of polymeric microspheres currently in use have been optimized to effectively protect their “protein cargo” from inactivation occurring in biological environments, preserving its bioactivity during release up to several weeks. The scenario of protein delivery would greatly benefit by strategies enabling the production of non-spherical particles. Herein we report an easy and effective stamp-based method to produce poly-lactic-glycolic-acid (PLGA) microparticles encapsulating Vascular Endothelial Growth Factor (VEGF) of different shapes. We demonstrate that PLGA microspheres can be deformed at room temperature exploiting solvent/non-solvent plasticization in order to preserve the properties of the starting microspheres. This gentle method allows the production of shaped particles that provide a prolonged release of VEGF in active form, as verified by an angiogenic assay. The retention of the biological activity of an extremely labile molecule, i.e. VEGF, lets us hypothesize that a wide variety of drug and protein encapsulated polymeric microspheres can be processed using this method.

  4. Sustained release poly (lactic-co-glycolic acid) microspheres of bone morphogenetic protein 2 plasmid/calcium phosphate to promote in vitro bone formation and in vivo ectopic osteogenesis

    PubMed Central

    Qiao, Chunyan; Zhang, Kai; Sun, Bin; Liu, Jinzhong; Song, Jiyu; Hu, Yue; Yang, Shihui; Sun, Hongchen; Yang, Bai

    2015-01-01

    Bone regeneration often requires continuous stimulation to promote local bone formation. In the present study, calcium phosphate (CaPi) was used to promote transfection of human bone morphogenetic protein 2 (BMP-2) cDNA plasmid, and poly (lactic-co-glycolic acid) (PLGA) was used to prepare microspheres of pBMP-2/CaPi (i.e., PLGA@pBMP-2/CaPi) using W/O/W double emulsion solvent evaporation method. We showed that PLGA@pBMP-2/CaPi microspheres were spherical with smooth surface, and the particle size ranged from 0.5 to 35 μm. Encapsulation efficiency was up to 30~50%. The release of BMP-2 cDNA from microspheres continued more than 30 days and constituted, less than 7.5% of total plasmid amount within the first 24 h. Real-time PCR results showed that co-culturing of PLGA@pBMP-2/CaPi with bone marrow-derived mesenchymal stem cells (BMSCs) increased calcium deposition and gene expressions of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), SP7, and collagen type I (COLL I) in a time-dependent manner. Finally, X-ray analysis demonstrated that in vivo delivery of PLGA@pBMP-2/CaPi microspheres into the tibialis anterior muscles of rats promoted the generation of osteoblasts, bone tissue, and bone structure. The findings suggested that PLGA@pBMP-2/CaPi microspheres can promote ectopic osteogenesis in non-bone tissues, with strong prospects in promoting bone regeneration. PMID:26885257

  5. Making Polymeric Microspheres

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Hyson, Michael T.; Chung, Sang-Kun; Colvin, Michael S.; Chang, Manchium

    1989-01-01

    Combination of advanced techniques yields uniform particles for biomedical applications. Process combines ink-jet and irradiation/freeze-polymerization techniques to make polymeric microspheres of uniform size in diameters from 100 to 400 micrometer. Microspheres used in chromatography, cell sorting, cell labeling, and manufacture of pharmaceutical materials.

  6. The osteogenic response of mesenchymal stem cells to an injectable PLGA bone regeneration system.

    PubMed

    Curran, Judith M; Fawcett, Sandra; Hamilton, Lloyd; Rhodes, Nicholas P; Rahman, Cheryl V; Alexander, Morgan; Shakesheff, Kevin; Hunt, John A

    2013-12-01

    The enrichment of substrates/surfaces with selected functional groups, methyl (-CH3), allyl amine (-NH2), allyl alcohol (-OH) and acrylic acid (-COOH), can be used to trigger mesenchymal stem (MSC) cell differentiation into specified lineages, minimising the need for exogenous biological supplementation. We present the successful translation of this research phenomenon to an injectable two phase injectable PLGA system, utilising plasma techniques, for the repair of bone defects. Modified microspheres were characterised using water contact angel (WCA), X-ray Photon Spectroscopy (XPS) and scanning electron microscopy (SEM). When cultured in contact with MSCs in vitro, the ability of the modified particles, within the 2 phase system, to induce differentiation was characterised using quantitative assays for cell viability and histological analysis for key markers of differentiation throughout the entirety of the three dimensional scaffold. Biological analysis proved that selected modified microspheres have the ability to induce MSC osteogenic (-NH2 modified scaffolds) and chondrogenic (-OH modified scaffolds) differentiation throughout the entirety of the formed scaffold. Therefore optimised plasma modification of microspheres is an effective tool for the production of injectable systems for the repair of bone and cartilage defects.

  7. Production of hollow aerogel microspheres

    SciTech Connect

    Upadhye, R.S.; Henning, S.A.

    1990-12-31

    A method is described for making hollow aerogel microspheres of 800--1200{mu} diameter and 100--300{mu} wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

  8. Production of hollow aerogel microspheres

    DOEpatents

    Upadhye, Ravindra S.; Henning, Sten A.

    1993-01-01

    A method is described for making hollow aerogel microspheres of 800-1200 .mu. diameter and 100-300 .mu. wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

  9. Using poly(lactic-co-glycolic acid) microspheres to encapsulate plasmid of bone morphogenetic protein 2/polyethylenimine nanoparticles to promote bone formation in vitro and in vivo.

    PubMed

    Qiao, Chunyan; Zhang, Kai; Jin, Han; Miao, Leiying; Shi, Ce; Liu, Xia; Yuan, Anliang; Liu, Jinzhong; Li, Daowei; Zheng, Changyu; Zhang, Guirong; Li, Xiangwei; Yang, Bai; Sun, Hongchen

    2013-01-01

    Repair of large bone defects is a major challenge, requiring sustained stimulation to continually promote bone formation locally. Bone morphogenetic protein 2 (BMP-2) plays an important role in bone development. In an attempt to overcome this difficulty of bone repair, we created a delivery system to slowly release human BMP-2 cDNA plasmid locally, efficiently transfecting local target cells and secreting functional human BMP-2 protein. For transfection, we used polyethylenimine (PEI) to create pBMP-2/PEI nanoparticles, and to ensure slow release we used poly(lactic-co-glycolic acid) (PLGA) to create microsphere encapsulated pBMP-2/PEI nanoparticles, PLGA@pBMP-2/PEI. We demonstrated that pBMP-2/PEI nanoparticles could slowly release from the PLGA@pBMP-2/PEI microspheres for a long period of time. The 3-15 μm diameter of the PLGA@pBMP-2/PEI further supported this slow release ability of the PLGA@pBMP-2/PEI. In vitro transfection assays demonstrated that pBMP-2/PEI released from PLGA@pBMP-2/PEI could efficiently transfect MC3T3-E1 cells, causing MC3T3-E1 cells to secrete human BMP-2 protein, increase calcium deposition and gene expressions of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), SP7 and I type collagen (COLL I), and finally induce MC3T3-E1 cell differentiation. Importantly, in vivo data from micro-computed tomography (micro-CT) and histological staining demonstrated that the human BMP-2 released from PLGA@pBMP-2/PEI had a long-term effect locally and efficiently promoted bone formation in the bone defect area compared to control animals. All our data suggest that our PLGA-nanoparticle delivery system efficiently and functionally delivers the human BMP-2 cDNA and has potential clinical application in the future after further modification.

  10. Metabolism of proteinoid microspheres

    NASA Technical Reports Server (NTRS)

    Nakashima, T.; Fox, S. W. (Principal Investigator)

    1987-01-01

    The literature of metabolism in proteinoids and proteinoid microspheres is reviewed and criticized from a biochemical and experimental point of view. Closely related literature is also reviewed in order to understand the function of proteinoids and proteinoid microspheres. Proteinoids or proteinoid microspheres have many activities. Esterolysis, decarboxylation, amination, deamination, and oxidoreduction are catabolic enzyme activities. The formation of ATP, peptides or oligonucleotides is synthetic enzyme activities. Additional activities are hormonal and inhibitory. Selective formation of peptides is an activity of nucleoproteinoid microspheres; these are a model for ribosomes. Mechanisms of peptide and oligonucleotide syntheses from amino acids and nucleotide triphosphate by proteinoid microspheres are tentatively proposed as an integrative consequence of reviewing the literature.

  11. Metabolism of proteinoid microspheres

    NASA Technical Reports Server (NTRS)

    Nakashima, T.; Fox, S. W. (Principal Investigator)

    1987-01-01

    The literature of metabolism in proteinoids and proteinoid microspheres is reviewed and criticized from a biochemical and experimental point of view. Closely related literature is also reviewed in order to understand the function of proteinoids and proteinoid microspheres. Proteinoids or proteinoid microspheres have many activities. Esterolyis, decarboxylation, amination, deamination, and oxidoreduction are catabolic enzyme activities. The formation of ATP, peptides or oligonucleotides is synthetic enzyme activities. Additional activities are hormonal and inhibitory. Selective formation of peptides is an activity of nucleoproteinoid microspheres; these are a model for ribosomes. Mechanisms of peptide and oligonucleotide syntheses from amino acids and nucleotide triphosphate by proteinoid microspheres are tentatively proposed as an integrative consequence of reviewing the literature.

  12. Hepatitis C virus E2 protein encapsulation into poly d, l-lactic-co-glycolide microspheres could induce mice cytotoxic T-cell response.

    PubMed

    Roopngam, Piyachat; Liu, Kewei; Mei, Lin; Zheng, Yi; Zhu, Xianbing; Tsai, Hsiang-I; Huang, Laiqiang

    Hepatitis C virus (HCV) is known to cause hepatitis and hepatocellular carcinoma. E2 envelope glycoprotein of HCV type (HCV-E2) has been reported to bind human host cells and is a major target for developing anti-HCV vaccines. However, the therapeutic vaccine for infected patients still needs further development. The vaccine aims to provide cytotoxic T-cells to eliminate infected cells and hepatocellular carcinoma. Currently, there is no effective HCV therapeutic vaccine because most chronically infected patients rarely generate cytotoxic T-cells, even though they have high levels of neutralizing antibodies. Therefore, the adjuvant must be applied to enhance the efficacy of the therapeutic vaccine. In this study, we constructed HCV1b-E2 recombinant protein, a truncated form of peptide, to combine with an effective vaccine adjuvant and delivery system by using poly d,l-lactic-co-glycolide (PLGA) microspheres. HCV1b-E2 protein was effectively encapsulated into PLGA microspheres (HCV1b-E2-PLGA) as a strategy to deliver an insoluble form of HCV1b-E2 protein. The size and shape of PLGA microspheres were generated properly to carry an insoluble form of viral peptide in vivo. The encapsulated viral protein was slowly and continuously released from PLGA microspheres, which indicated the property of the adjuvant. HCV1b-E2-PLGA can trigger a cell-mediated immune response by inducing an expression of mice CD8(+) T-cells. Our results demonstrated that HCV1b-E2-PLGA-immunized mice have a significantly increased CD8(+) T-cell number, whereas HCV1b-E2-immunized mice have a lower number of CD8(+) T-cells. Moreover, HCV1b-E2-PLGA could induce a specific antibody to viral protein, and the immune cells could secrete IFN-γ, which is a significant cytokine for viral response. Thus, HCV1b-E2-PLGA is shown to have adjuvant property and efficacy in the murine model, which is a good strategy to develop HCV prophylactic and therapeutic vaccines.

  13. Hepatitis C virus E2 protein encapsulation into poly d, l-lactic-co-glycolide microspheres could induce mice cytotoxic T-cell response

    PubMed Central

    Roopngam, Piyachat; Liu, Kewei; Mei, Lin; Zheng, Yi; Zhu, Xianbing; Tsai, Hsiang-I; Huang, Laiqiang

    2016-01-01

    Hepatitis C virus (HCV) is known to cause hepatitis and hepatocellular carcinoma. E2 envelope glycoprotein of HCV type (HCV-E2) has been reported to bind human host cells and is a major target for developing anti-HCV vaccines. However, the therapeutic vaccine for infected patients still needs further development. The vaccine aims to provide cytotoxic T-cells to eliminate infected cells and hepatocellular carcinoma. Currently, there is no effective HCV therapeutic vaccine because most chronically infected patients rarely generate cytotoxic T-cells, even though they have high levels of neutralizing antibodies. Therefore, the adjuvant must be applied to enhance the efficacy of the therapeutic vaccine. In this study, we constructed HCV1b-E2 recombinant protein, a truncated form of peptide, to combine with an effective vaccine adjuvant and delivery system by using poly d,l-lactic-co-glycolide (PLGA) microspheres. HCV1b-E2 protein was effectively encapsulated into PLGA microspheres (HCV1b-E2-PLGA) as a strategy to deliver an insoluble form of HCV1b-E2 protein. The size and shape of PLGA microspheres were generated properly to carry an insoluble form of viral peptide in vivo. The encapsulated viral protein was slowly and continuously released from PLGA microspheres, which indicated the property of the adjuvant. HCV1b-E2-PLGA can trigger a cell-mediated immune response by inducing an expression of mice CD8+ T-cells. Our results demonstrated that HCV1b-E2-PLGA-immunized mice have a significantly increased CD8+ T-cell number, whereas HCV1b-E2-immunized mice have a lower number of CD8+ T-cells. Moreover, HCV1b-E2-PLGA could induce a specific antibody to viral protein, and the immune cells could secrete IFN-γ, which is a significant cytokine for viral response. Thus, HCV1b-E2-PLGA is shown to have adjuvant property and efficacy in the murine model, which is a good strategy to develop HCV prophylactic and therapeutic vaccines. PMID:27789948

  14. Synthesis and characterization of poly(lactic acid-co-glycolic acid) complex microspheres as drug carriers.

    PubMed

    Wang, Fang; Liu, Xiuxiu; Yuan, Jian; Yang, Siqian; Li, Yueqin; Gao, Qinwei

    2016-10-01

    Poly(lactic-co-glycolic) acid (PLGA) is synthesized via melt polycondensation directly from lactic acid and glycolic acid with a feed molar ratio of 75/25. Bovine serum albumin, which is used as model protein, is entrapped into the poly(lactic-co-glycolic acid) microspheres with particle size of 260.9 ± 20.0 nm by the double emulsification method. Then it is the first report of producing more carboxyl groups by poly(lactic-co-glycolic acid) surface hydrolysis. The purpose is developing poly(lactic-co-glycolic acid) microspheres surface, which is modified with chitosan by chemical reaction between carboxyl groups and amine groups. The particle size and the positive zeta potential of the poly(lactic-co-glycolic acid)/chitosan microspheres are 388.2 ± 35.6 nm and 10.4 ± 2.9 mV, respectively. The drug loading ratio and encapsulation efficacy of poly(lactic-co-glycolic acid)/chitosan microspheres are 36.3% and 57.5%, which are higher than PLGA microspheres. Furthermore, the drug burst release of poly(lactic-co-glycolic acid)/chitosan microspheres at 10 h is decreased to 21.72% while the corresponding value of the poly(lactic-co-glycolic acid) microsphere is 64.56%. These results reveal that surface hydrolysis modification of poly(lactic-co-glycolic acid) is an efficient method to improve the negative potential and chemical reaction properties of the polymer. And furthermore, this study shows that chitosan-modified poly(lactic-co-glycolic acid) microspheres is a promising system for the controlled release of pharmaceutical proteins.

  15. Minimal injection site pain and high patient satisfaction during treatment with long-acting risperidone.

    PubMed

    Lindenmayer, Jean-Pierre; Jarboe, Kathleen; Bossie, Cynthia A; Zhu, Young; Mehnert, Angelika; Lasser, Robert

    2005-07-01

    Long-acting injectable antipsychotic formulations of conventional antipsychotics were developed to address the problem of partial adherence among patients with schizophrenia. Injection site pain, other skin reactions and patient satisfaction with treatment were assessed in two large, multicentre studies of long-acting injectable risperidone (Risperdal CONSTA, Janssen Pharmaceutica Products, Titusville, New Jersey, USA), the first available long-acting atypical antipsychotic agent. Patients rated injection site pain using a 100-mm Visual Analogue Scale (VAS), and investigators rated injection site pain, redness, swelling and induration. Patient satisfaction with treatment was assessed with the Drug Attitude Inventory (DAI). VAS pain ratings were low at all visits across all doses in both studies, and decreased from first to final injection. In the 12-week, double-blind study, mean +/- SD VAS scores at the first and final injections were 15.6 +/- 20.7 and 12.5 +/- 18.3 for placebo-treated patients, and 11.8 +/- 14.4 (first) and 10.0 +/- 12.4 (final) for 25 mg; 16.3+/-21.9 (first) and 13.6 +/- 21.7 (final) for 50 mg; and 16.0 +/- 17.9 (first) and 9.6 +/- 16.0 (final, P<0.01) for 75 mg of long-acting risperidone. Mean VAS scores in the 50-week, open-label study at the first and final injection were: 17.9 +/- 22.2 (first) and 9.5 +/- 16.7 (final, P<0.0001) for 25 mg; 18.1 +/- 19.7 (first) and 10.4 +/- 14.8 (final, P<0.0001) for 50 mg; and 18.5 +/- 21.6 (first) and 13.6 +/- 19.9 (final, P = 0.0001) for 75 mg of long-acting risperidone. Overall, there was no or minimal injection site pain and skin reactions were rare. Mean DAI ratings were available for the 50-week study and indicated high patient satisfaction throughout the trial (baseline = 7.30; endpoint = 7.70; P<0.0001 versus baseline). These findings may positively affect patient and clinician attitudes towards long-term therapy with long-acting injectable risperidone.

  16. Evaluation of Orntide microspheres in a rat animal model and correlation to in vitro release profiles.

    PubMed

    Kostanski, J W; Dani, B A; Reynolds, G A; Bowers, C Y; DeLuca, P P

    2000-10-01

    Orntide acetate, a novel luteinizing hormone-releasing hormone (LHRH) antagonist, was prepared and evaluated in vivo in 30-day and 120-day sustained delivery formulations using a rat animal model. Orntide poly(d,l-lactide-co-glycolide) (PLGA) and poly(d,l- lactide) (PLA) microspheres were prepared by a dispersion method and administered subcutaneously in a liquid vehicle to rats at 2.2 mg Orntide/kg of body weight (30-day forms) or 8.8 mg Orntide/kg (120-day forms). Serum levels of Orntide and testosterone were monitored by radioimmunoassays, and a dose-response study at 4 doses (3, 2.25, 1.5, and 1.75 mg Orntide/kg) was conducted to determine the effective dose of Orntide. Microspheres with diameters between 3.9 and 14 micron were prepared. The onset and duration of testosterone suppression varied for different microsphere formulations and were influenced both by polymer properties and by microsphere characteristics. Microspheres prepared with 50:50 and 75:25 copolymers effectively sustained peptide release for 14 to 28 days, whereas an 85:15 copolymer and the PLA microspheres extended the pharmacological response for more than 120 days. Increase in drug load generally accelerated peptide release from the microspheres, resulting in higher initial serum levels of Orntide and shorter duration of the release. In general, apparent release was faster in vivo than under in vitro conditions. Orntide microspheres effectively suppressed testosterone in rats, providing rapid onset of release and extended periods of chemical castration. Testosterone suppression occurred immediately after microsphere administration without the initial elevation seen with LHRH superagonists.

  17. Validation of USP apparatus 4 method for microsphere in vitro release testing using Risperdal Consta.

    PubMed

    Rawat, Archana; Stippler, Erika; Shah, Vinod P; Burgess, Diane J

    2011-11-28

    The current manuscript addresses the need for a validated in vitro release testing method for controlled release parenteral microspheres. A USP apparatus 4 method was validated with the objective of possible compendial adaptation for microsphere in vitro release testing. Commercial microspheres (Risperdal Consta) were used for method validation. Accelerated and real-time release tests were conducted. The accelerated method had significantly reduced test duration and showed a good correlation with the real-time release profile (with limited number of sample analysis). Accelerated conditions were used for method validation (robustness and reproducibility). The robustness testing results revealed that release from the microspheres was not flow rate dependent and was not affected by minor variations in the method (such as cell preparation technique, amount of microspheres, flow-through cell size and size of glass beads). The significant difference in the release profile with small variations (± 0.5°C) in temperature was shown to be due to a change in risperidone catalyzed PLGA degradation in response to temperature. The accelerated method was reproducible as changing the system/equipment or the analyst did not affect the release profile. This work establishes the suitability of the modified USP apparatus 4 for possible compendial adaptation for drug release testing of microspheres.

  18. Effectiveness of long-acting antipsychotics in clinical practice: 2. Effects of antipsychotic polypharmacy on risperidone long-acting injection and zuclopenthixol decanoate

    PubMed Central

    Cordiner, Matthew; Shajahan, Polash; McAvoy, Sarah; Bashir, Muhammad; Taylor, Mark

    2016-01-01

    Objectives: Antipsychotic polypharmacy (APP) is common clinical practice. Theoretically, APP runs the risk of additional side effects, drug interactions, adherence and cost. A limited evidence base is emerging to support the effectiveness of APP in clinical practice. Our companion paper highlighted the extent of APP alongside commonly prescribed long-acting antipsychotic injections (LAIs). We aimed to examine the effects of APP on discontinuation rates and Clinical Global Impression (CGI) outcomes in patients commenced on risperidone long-acting injection (RLAI) and zuclopenthixol decanoate. Method: LAI-naïve patients commenced on RLAI (n = 102) and zuclopenthixol decanoate(n = 105) were identified using our electronic patient record (running from 2002) within NHS Lanarkshire, Scotland, UK. This was a retrospective, electronic case note review with an 18-month follow up. Patient groups were divided into those receiving the LAI as the sole antipsychotic and those who were receiving additional oral antipsychotic polypharmacy (APP) for at least 50% of the duration of the treatment with their LAI. Kaplan–Meier statistics were calculated for discontinuation rates. CGI severity and improvement scores were retrospectively assigned by the investigating team. Results: Antipsychotic polypharmacy occurred with RLAI (37%) and zuclopenthixol decanoate (46%) and was associated with lower discontinuation rates (statistical significant with zuclopenthixol for any cause and adverse effects discontinuation). APP had no adverse outcomes on hospital admissions or CGI ratings. Patients on APP did not have more severe, chronic or treatment resistant illnesses. Conclusions: For RLAI and zuclopenthixol decanoate, APP had some favourable outcomes when examining discontinuation rates for any cause, and adverse effects. This was unexpected as we had considered APP would signal illness chronicity and severity and be associated with increased adverse effects resulting in early

  19. [Intravenous regional anesthesia with long-acting local anesthetics. An update].

    PubMed

    Atanassoff, P G; Lobato, A; Aguilar, J L

    2014-02-01

    Intravenous regional anesthesia is a widely used technique for brief surgical interventions, primarily on the upper limbs and less frequently, on the lower limbs. It began being used at the beginning of the 20th century, when Bier injected procaine as a local anesthetic. The technique to accomplish anesthesia has not changed much since then, although different drugs, particularly long-acting local anesthetics, such as ropivacaine and levobupivacaine in low concentrations, were introduced. Additionally, drugs like opioids, muscle relaxants, paracetamol, neostigmine, magnesium, ketamine, clonidine, and ketorolac, have all been investigated as adjuncts to intravenous regional anesthesia, and were found to be fairly useful in terms of an increased onset of operative anesthesia and longer lasting perioperative analgesia. The present article provides an overview of current knowledge with emphasis on long-acting local anesthetic drugs.

  20. PHARMACOKINETICS OF CEFTIOFUR CRYSTALLINE FREE ACID, A LONG-ACTING CEPHALOSPORIN, IN AMERICAN FLAMINGOS (PHOENICOPTERUS RUBER).

    PubMed

    Kilburn, Jennifer J; Cox, Sherry K; Backues, Kay A

    2016-06-01

    Antibiotic usage is a vital component of veterinary medicine but the unique anatomy of some species can make administration difficult. The objective of this study was to determine the pharmacokinetic parameters of ceftiofur crystalline free acid (CCFA), a long-acting cephalosporin antibiotic, after parenteral administration in American flamingos ( Phoenicopterus ruber ). A dose of 10 mg/kg of CCFA was administered intramuscularly to 11 birds and blood was collected at various time points from 0 to 192 hr. Pharmacokinetic parameters for ceftiofur equivalents were determined and reached levels above minimum inhibitory concentrations of various bacterial organisms in other avian species through 96 hr in 9/11 birds. Based on these findings and comparison to other avian studies, ceftiofur crystalline free acid appears to be a long-acting antibiotic option for American flamingos. Administration of this antibiotic should be utilized in conjunction with culture and sensitivity of suspected pathogens.

  1. Emerging treatments in the management of bipolar disorder – focus on risperidone long acting injection

    PubMed Central

    El-Hage, Wissam; Surguladze, Simon A

    2010-01-01

    Bipolar disorder is a life-long psychiatric illness characterized by a high frequency of relapses and substantial societal costs. Almost half of the patients are prescribed second generation antipsychotics for treatment of manic states, or as the maintenance therapy. Risperidone long acting injection (RLAI) as a monotherapy or as adjunctive therapy to lithium or valproate for the maintenance treatment of bipolar I disorder was approved by Food and Drug Administration (FDA) in United States in May 2009. In this review we will consider the aspects of pharmacology, pharmacokinetics, metabolism, safety and tolerability, and clinical trials focusing on the efficacy of RLAI in bipolar disorder. The patients’ perspective and attitudes to long-acting injections will also be discussed. PMID:20856609

  2. Tracking the effect of microspheres size on the drug release from a microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot in vitro and in vivo.

    PubMed

    Lin, Xia; Wang, Jing; Xu, Yuhong; Tang, Xing; Chen, Jian; Zhang, Yu; Zhang, Yan; Yang, Ziyi

    2016-09-01

    The effects of particle size of microspheres on the drug release from a microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot (m-SAIB) was investigated to develop a long-term sustained release drug delivery system with low burst release both in vitro and in vivo. A model drug, risperidone, was first encapsulated into PLGA microspheres with different particle sizes using conventional emulsification and membrane emulsification methods. The m-SAIB was prepared by dispersing the risperidone-microspheres in the SAIB depot. The drug release from m-SAIB was double controlled by the drug diffusion from the microspheres into SAIB matrix and the drug diffusion from the SAIB matrix into the medium. Large microspheres (18.95 ± 18.88 µm) prepared by the conventional homogenization method exhibited porous interior structure, which contributed to the increased drug diffusion rate from microspheres into SAIB matrix. Consequently, m-SAIB containing such microspheres showed rapid initial drug release (Cmax = 110.1 ±54.2 ng/ml) and subsequent slow drug release (Cs(4-54d)= 2.7 ± 0.8 ng/ml) in vivo. Small microspheres (5.91 ± 2.24 µm) showed dense interior structure with a decreased drug diffusion rate from microspheres into SAIB matrix. The initial drug release from the corresponding m-SAIB was significantly decreased (Cmax = 40.9 ± 13.7 ng/ml), whereas the drug release rate from 4 to 54 d was increased (Cs(4-54d)=4.1 ± 1.0 ng/ml). By further decreasing the size of microspheres to 3.38 ± 0.70 µm, the drug diffusion surface area was increased, which subsequently increased the drug release from the m-SAIB. These results demonstrate that drug release from the m-SAIB can be tailored by varying the size of microspheres to reduce the in vivo burst release of SAIB system alone.

  3. Committee opinion no. 539: adolescents and long-acting reversible contraception: implants and intrauterine devices.

    PubMed

    2012-10-01

    Long-acting reversible contraception (LARC)—intrauterine devices and the contraceptive implant—are safe and appropriate contraceptive methods for most women and adolescents. The LARC methods are top-tier contraceptives based on effectiveness, with pregnancy rates of less than 1% per year for perfect use and typical use. These contraceptives have the highest rates of satisfaction and continuation of all reversible contraceptives. Adolescents are at high risk of unintended pregnancy and may benefit from increased access to LARC methods.

  4. Pharmacokinetics of oxytetracycline in goats: modifications induced by a long-acting formulation.

    PubMed

    Escudero, E; Carceles, C M; Serrano, J M

    1994-12-03

    The pharmacokinetics of oxytetracycline were studied in goats, after the intravenous and intramuscular injection of a conventional and long-acting formulation. The antibiotic was distributed according to an open two-compartment model. The apparent volume of distribution (Vz) and the central compartment volume (Vc) were 1.443 litres/kg and 0.453 litre/kg, respectively, and the total body clearance was 0.156 litre/kg/hour. The mean half-lives (T1/2 lambda z) of the conventional formulation after intravenous and intramuscular administration were six hours 28 minutes and 10 hours 38 minutes, respectively, whereas the long-acting formulation had half-lives of six hours 36 seconds and 29 hours, respectively, after intravenous and intramuscular injection. From the results of these single administrations two intramuscular dosage regimens can be proposed that achieve minimum concentrations of over 0.5 mg/litre (the minimum inhibitory concentration for most susceptible pathogens): with the conventional formulation by administering an initial dose of 10 mg/kg and a maintenance dose of 8.5 mg/kg every 24 hours, and with the long-acting formulation by administering an initial dose of 20 mg/kg and a maintenance dose of 14 mg/kg every 48 hours.

  5. Long-acting Injectable Risperidone Use in an 11-Years-Old Bipolar Child

    PubMed Central

    KARAKOÇ DEMİRKAYA, Sevcan; ZOROĞLU, Süleyman Salih

    2016-01-01

    Early-onset bipolar disorder is difficult for child psychiatrists in terms of both diagnosis and treatment. The proper diagnostic evaluation is negatively impacted by the atypical clinical manifestation and rapid cycling pattern of the disease, together with common comorbidity with attention-deficit hyperactivity disorder and anxiety disorder. In addition to poor insight, nonadherence to treatment, poor family coping skills, and insufficient child psychiatric inpatient units make clinicians unsuccessful in following up and treating such patients. Risperidone is a commonly used atypical antipsychotic it has been approved for the treatment of manic and mixed episodes of bipolar disorder even in 10–17-year-old patients, and it is commonly used. It has a long-acting injectable formulation. Studies on its long-acting form in younger children are limited. In this case presentation, the diagnostic procedure in an 11-year old child with bipolar disorder will be presented. Long-acting injectable risperidone use in the case of nonadherence to treatment and observed side effects will be discussed. PMID:28360814

  6. A case of suicide attempt with long-acting methylphenidate (Concerta).

    PubMed

    Ozdemir, Esra; Karaman, Mehmet Goksin; Yurteri, Nihal; Erdogan, Ayten

    2010-11-01

    The prescribed use of methylphenidate in the treatment of attention deficit hyperactivity disorder (ADHD) is widespread. The intranasal and parenteral abuse of methylphenidate (Ritalin) among teenagers is becoming increasingly more common, and deaths have been reported. Newer medical treatment options of long-acting stimulants offer effective treatment with a lower risk of abuse potential. We describe a case of a 17-year-old girl who had attempted suicide by ingesting 270 mg of Concerta. During the third years of treatment with Concerta, parents of patient reported that the patient had a depressive mood in the last week, and had attempted suicide with five tablets of Concerta 54 mg. She was sent to a local hospital with a diagnosis of long-acting methylphenidate overdose. All of vital and laboratory findings were normal except heart rate, which was 132 beats/min. Since more than 3 h have elapsed after the time of ingestion, activated charcoal administration was not carried out at the hospital. She was only observed for 12 h at the emergency department and later discharged from the hospital. While long-acting stimulants offer lower risk of abuse, their greater availability increases the likelihood of ingestion of this nature. Education of clinicians and families to be aware of this risk should reduce the frequency of this complication of treatment.

  7. How Do Dual Long-acting Bronchodilators Prevent Exacerbations of Chronic Obstructive Pulmonary Disease?

    PubMed

    Beeh, Kai M; Burgel, Pierre-Regis; Franssen, Frits M E; Lopez-Campos, Jose Luis; Loukides, Stelios; Hurst, John R; Fležar, Matjaž; Ulrik, Charlotte Suppli; Di Marco, Fabiano; Stolz, Daiana; Valipour, Arschang; Casserly, Brian; Ställberg, Björn; Kostikas, Konstantinos; Wedzicha, Jadwiga A

    2016-12-06

    Decreasing the frequency and severity of exacerbations is one of the main goals of treatment for patients with chronic obstructive pulmonary disease (COPD). Several studies have documented that long-acting bronchodilators (LABDs) can reduce exacerbation rate and/or severity, and others have shown that combinations of long-acting β2-adrenergic agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) provide greater reductions in exacerbation frequency than either their monocomponents or LABA/inhaled corticosteroids (LABA/ICS) combinations in patients at low and high risk for these events. In this review, small groups of experts critically evaluated mechanisms potentially responsible for the increased benefit of LABA/LAMA combinations over single LABDs or LABA/ICS in decreasing exacerbation. These included effects on lung hyperinflation and mechanical stress, inflammation, excessive mucus production with impaired mucociliary clearance, and symptom severity. The data assembled and analyzed by each group were reviewed by all authors and combined into this manuscript. Available clinical results support the possibility that effects of LABA/LAMA combinations on hyperinflation, mucociliary clearance, and symptom severity may all contribute to decreasing exacerbations. While preclinical studies suggest LABAs and LAMAs have anti-inflammatory effects, such effects have not been demonstrated yet in patients with COPD.

  8. The Promise and Pitfalls of Long Acting Injectable Agents for HIV Prevention

    PubMed Central

    Kofron, Ryan; McCauley, Marybeth

    2016-01-01

    Purpose of review Pre-exposure prophyalxis (PrEP) for HIV prevention is highly effective when taken as prescribed. Adherence to required dosing regimens for protection may pose challenges. Long Acting agents for HIV prevention may have the potential to improve adherence via favorable pharmacokinetics supportive of infrequent dosing. This review focuses on the potential benefits and considerations for the study and use of two long acting injectable agents, cabotegravir (GSK1265744 LA, CAB LA) and rilpivirine (TMC278 LA, RPV LA), for use as chemoprophylaxis for HIV prevention. Recent findings Oral RPV is FDA approved for HIV treatment (in combination with other antiretrovirals). Both CAB LA and RPV LA are currently in Phase 2a safety/tolerability/pharmacokinetic studies in anticipation and support of future efficacy evaluation. Both agents have favorable pharmacokinetics, and use is complicated by injection site reactions. Summary Long acting injectable formulations, if safe and well tolerated, may improve pharmacokinetic coverage of exposures to HIV infection. Complexities around safety, tolerability, and starting/stopping protocols require careful consideration. PMID:26633643

  9. Long-term use of short- and long-acting nitrates in stable angina pectoris.

    PubMed

    Kosmicki, Marek Antoni

    2009-05-01

    Long-acting nitrates are effective antianginal drugs during initial treatment. However, their therapeutic value is compromised by the rapid development of tolerance during sustained therapy, which means that their clinical efficacy is decreased during long-term use. Sublingual nitroglycerin (NTG), a short-acting nitrate, is suitable for the immediate relief of angina. In patients with stable angina treated with oral long-acting nitrates, NTG maintains its full anti-ischemic effect both after initial oral ingestion and after intermittent long-term oral administration. However, NTG attenuates this effect during continuous treatment, when tolerance to oral nitrates occurs, and this is called cross-tolerance. In stable angina long-acting nitrates are considered third-line therapy because a nitrate-free interval is required to avoid the development of tolerance. Nitrates vary in their potential to induce the development of tolerance. During long-lasting nitrate therapy, except pentaerythritol tetranitrate (PETN), one can observe the development of reactive oxygen species (ROS) inside the muscular cell of a vessel wall, and these bind with nitric oxide (NO). This leads to decreased NO activity, thus, nitrate tolerance. PETN has no tendency to form ROS, and therefore during long-term PETN therapy, there is probably no tolerance or cross-tolerance, as during treatment with other nitrates.

  10. Factors associated with relapse in schizophrenia despite adherence to long-acting injectable antipsychotic therapy.

    PubMed

    Alphs, Larry; Nasrallah, Henry A; Bossie, Cynthia A; Fu, Dong-Jing; Gopal, Srihari; Hough, David; Turkoz, Ibrahim

    2016-07-01

    Many patients with schizophrenia will relapse despite uninterrupted antipsychotic (AP) long-acting therapy (LAT). This exploratory analysis examined variables associated with relapse despite ensured adherence to LAT. This was a post-hoc exploratory analysis of a 1-year study of risperidone long-acting injection in patients with stable schizophrenia or schizoaffective disorder (NCT00297388; N=323). Patients were discontinued from previous oral APs and randomly assigned to biweekly intramuscular injections of risperidone long-acting injectable 50 (n=163) or 25 mg (n=161) for 52 weeks. Cox proportional hazards regression models examined variables putatively associated with relapse. A total of 59/323 (18.3%) patients relapsed over 12 months despite continuous AP LAT. Variables associated with the risk of relapse included illness duration (6.0% increase each year; P=0.0003) and country (Canada vs. USA, 4.7-fold risk increase; P=0.0008). When illness duration was further categorized as ≤5, 6-10, and >10 years, patients with an illness duration of >10 versus ≤5 years were at greatest risk of relapse (>10 vs. ≤5 years associated with a 4.4-fold increase in the risk of relapse; P=0.0181). Findings suggest that patients with more chronic illness have a greater risk of relapse despite ensured treatment adherence, supporting the need for early intervention to prevent the deleterious effects of chronicity.

  11. Long-acting Injectable Risperidone Use in an 11-Years-Old Bipolar Child.

    PubMed

    Karakoç Demirkaya, Sevcan; Zoroğlu, Süleyman Salih

    2016-12-01

    Early-onset bipolar disorder is difficult for child psychiatrists in terms of both diagnosis and treatment. The proper diagnostic evaluation is negatively impacted by the atypical clinical manifestation and rapid cycling pattern of the disease, together with common comorbidity with attention-deficit hyperactivity disorder and anxiety disorder. In addition to poor insight, nonadherence to treatment, poor family coping skills, and insufficient child psychiatric inpatient units make clinicians unsuccessful in following up and treating such patients. Risperidone is a commonly used atypical antipsychotic it has been approved for the treatment of manic and mixed episodes of bipolar disorder even in 10-17-year-old patients, and it is commonly used. It has a long-acting injectable formulation. Studies on its long-acting form in younger children are limited. In this case presentation, the diagnostic procedure in an 11-year old child with bipolar disorder will be presented. Long-acting injectable risperidone use in the case of nonadherence to treatment and observed side effects will be discussed.

  12. Microsphere Insulation Panels

    NASA Technical Reports Server (NTRS)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  13. Peptide/protein vaccine delivery system based on PLGA particles

    PubMed Central

    Allahyari, Mojgan; Mohit, Elham

    2016-01-01

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

  14. Budget Impact of Long-Acting Insulin Analogues: The Case in Brazil

    PubMed Central

    da Silva, Everton Nunes; Pereira, Maurício G

    2016-01-01

    Background Long-acting insulin analogues for type 1 diabetes (T1D) treatment have been available on the Brazilian market since 2002. However, the population cannot access the analogues through the public health system. Objective To estimate the incremental budget impact of long-acting insulin analogues coverage for T1D patients in the Brazilian public health system compared to NPH insulin. Methods We performed a budget impact analysis of a five-year period. The eligible population was projected using epidemiological data from the International Diabetes Federation estimates for patients between 0–14 and 20–79 years old. The prevalence of T1D was estimated in children, and the same proportion was applied to the 15-19-year-old group due to a gap in epidemiological information. We considered 4,944 new cases per year and a 34.61/100,000 inhabitants mortality rate. Market share for long-acting insulin analogues was assumed as 20% in the first year, reaching 40% in the fifth year. The mean daily dose was taken from clinical trials. We calculated the bargaining power of the Ministry of Health by dividing the price paid for human insulin in the last purchase by the average regulated price. We performed univariate and multivariate sensitivity analyses. Results The incremental budget impact of long-acting insulin analogues was US$ 28.6 million in the first year, and reached US$ 58.7 million in the fifth year. The total incremental budget impact was US$ 217.9 million over the five-year period. The sensitivity analysis showed that the percentage of T1D among diabetic adults and the insulin analogue price were the main factors that affected the budget impact. Conclusions The cost of the first year of long-acting insulin analogue coverage would correspond to 0.03% of total public health expenditure. The main advantage of this study is that it identifies potential bargaining power because it features more realistic profiles of resource usage, once centralized purchasing is

  15. Acceleration of hard and soft tissue healing in the oral cavity by a single transmucosal injection of fluvastatin-impregnated poly (lactic-co-glycolic acid) microspheres. An in vitro and rodent in vivo study.

    PubMed

    Yasunami, Noriyuki; Ayukawa, Yasunori; Furuhashi, Akihiro; Atsuta, Ikiru; Rakhmatia, Yunia Dwi; Moriyama, Yasuko; Masuzaki, Tomohiro; Koyano, Kiyoshi

    2015-12-23

    Antihyperlipidemic drug statins reportedly promote both bone formation and soft tissue healing. We examined the effect of sustained-release, fluvastatin-impregnated poly(lactic-co-glycolic acid) (PLGA) microspheres on the promotion of bone and gingival healing at an extraction socket in vivo, and the effect of fluvastatin on epithelial cells and fibroblasts in vitro. The maxillary right first molar was extracted in rats, then one of the following was immediately injected, as a single dose, into the gingivobuccal fold: control (no administration), PLGA microspheres without a statin (active control), or PLGA microspheres containing 20 or 40 μg kg(-1) of fluvastatin. At days 1, 3, 7, 14, and 28 after injection, bone and soft tissue healing were histologically evaluated. Cell proliferation was measured under the effect of fluvastatin at dosages of 0, 0.01, 0.1, 1.0, 10, and 50 μM. Cell migration and morphology were observed at dosages of 0 and 0.1 μM. Following tooth extraction, the statin significantly enhanced bone volume and density, connective tissue volume, and epithelial wound healing. In the in vitro study, it promoted significant proliferation and migration of epithelial cells and fibroblasts. A single dose of topically administered fluvastatin-impregnated PLGA microspheres promoted bone and soft tissue healing at the extraction site.

  16. Organic aerogel microspheres

    DOEpatents

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  17. Organic aerogel microspheres

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  18. Cross-sectional comparison of first-generation antipsychotic long-acting injections vs risperidone long-acting injection: patient-rated attitudes, satisfaction and tolerability

    PubMed Central

    Singh, Sourabh Moti; Haddad, Peter M.; Husain, Nusrat; Heaney, Eamonn; Tomenson, Barbara; Chaudhry, Imran B.

    2016-01-01

    Objectives: The objective of this study was to compare patients’ attitudes and satisfaction with medication and patient-rated tolerability between those prescribed a first-generation antipsychotic long-acting injection (FGA-LAI) and those prescribed risperidone long-acting injection (RLAI). Method: A cross-sectional study of a representative sample of outpatients prescribed an FGA-LAI or RLAI for a minimum of 6 months and attending a depot clinic. Attitudes to medication were assessed by the Drug Attitude Inventory (DAI-30), tolerability was measured by the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS) and satisfaction with antipsychotic medication was assessed by the Satisfaction with Antipsychotic Medication (SWAM) scale. Results: The RLAI (n = 28) and FGA-LAI (n = 39) groups did not differ in terms of mean age, sex, diagnosis and ethnicity. All individual LAIs were prescribed within British National Formulary limits. The most commonly prescribed FGA-LAI was flupentixol decanoate (n = 22). There was no significant difference between the RLAI and FGA-LAI groups in terms of mean total scores on the DAI-30, LUNSERS and SWAM or the tolerability subscales of the LUNSERS or the two subscales (treatment acceptability and medication insight) of the SWAM. In both LAI groups there was a low level of side effects (LUNSERS) and a generally positive attitude (DAI-30) and reasonable satisfaction (SWAM) with medication. Conclusions: Patients treated with FGA-LAI and RLAI for at least 6 months did not differ in terms of patient-rated tolerability, attitudes and satisfaction with medication. The current design cannot determine whether differences would have been evident earlier on during treatment. These results should be regarded as preliminary and are subject to prescribing bias. Randomized studies avoid prescribing bias and are a superior way to compare specific LAIs. Ideally randomized studies should include patient-rated outcome measures including

  19. Compartmentalization in proteinoid microspheres

    NASA Technical Reports Server (NTRS)

    Brooke, S.; Fox, S. W.

    1977-01-01

    Proteinoid microspheres with stable internal compartments and internal structure are made from acidic proteinoid and basic proteinoid with calcium. The populations of microspheres are characterized by a wide diversity of structure. A model of primitive intracellular communication is suggested by the observed movement of internal particles between compartments of a multicompartmentalized unit. Differential response to pH change and to temperature change has been demonstrated within one population and suggests one mode of adaptive selection among primordial cell populations.

  20. Use of long-acting reversible contraceptives to reduce the rate of teen pregnancy.

    PubMed

    Rome, Ellen

    2015-11-01

    Long-acting reversible contraceptives (LARCs) are safe for use in adolescents and do not rely on compliance or adherence for effectiveness. Continuation rates are higher and pregnancy rates are lower for adolescent users of LARCs compared with short-acting methods such as oral contraceptives. Similarly, repeat pregnancy rates are lower when LARCs are used compared with other forms of contraception. Myths and misconceptions about LARCs and other contraceptives remain a barrier to their use. Health care providers are in a unique position to provide confidential care to adolescents, and should provide education to them about the various contraceptive options, especially LARCs.

  1. The role of inhaled long-acting beta-2 agonists in the management of asthma.

    PubMed Central

    Kelly, H. William; Harkins, Michelle S.; Boushey, Homer

    2006-01-01

    The role of inhaled beta-2 agonists in the management of asthma has changed significantly over the last several years. This review outlines the most recent understanding of the pathophysiology of asthma and the studies that define the roles that both short- and long-acting beta-2 agonists play in therapy for this disease. A concentration on the clinical pharmacology and genetic implications for clinical use of this class of drugs in accordance with the national and international guidelines are described. PMID:16532973

  2. Prevention of unintended pregnancy: a focus on long-acting reversible contraception.

    PubMed

    Pickle, Sarah; Wu, Justine; Burbank-Schmitt, Edith

    2014-06-01

    This article summarizes the literature regarding the epidemiology and prevention of unintended pregnancy in the United States. Because of the Affordable Care Act and its accompanying contraceptive provision, there is a need for more primary care clinicians to provide family planning services. Office-based interventions to incorporate family planning services in primary care are presented, including clinical tools and electronic health record use. Special attention is paid to long-acting reversible contraceptive methods (the subdermal implant and intrauterine devices); these highly effective and safe methods have the greatest potential to decrease the rate of unintended pregnancy, but have been underused.

  3. Long-Acting Reversible Contraception: An Essential Guide for Pediatric Primary Care Providers.

    PubMed

    Allen, Suzanne; Barlow, Erin

    2017-04-01

    Long-acting reversible contraception (LARC) methods are 20% more effective than traditional contraceptives and are recommended by the American Academy of Pediatrics and American College of Obstetrics and Gynecology as first-line contraception for adolescent girls. Large studies show that LARC use reduces unintended pregnancies, increases user satisfaction, and prolongs duration of use. This article prepares the primary care provider (PCP) with knowledge on safety, efficacy, eligibility, confidentiality, anticipatory guidance, how to find a LARC provider, and guidance on common side effects so the PCP can confidently counsel adolescent patients on LARC methods.

  4. Therapeutic Options for Unscheduled Bleeding Associated with Long-Acting Reversible Contraception.

    PubMed

    Friedlander, EmmaKate; Kaneshiro, Bliss

    2015-12-01

    Long-acting reversible contraception (LARC) is the most effective form of reversible contraception. Although most women are satisfied with LARC methods, unscheduled bleeding and spotting are common reasons for method dissatisfaction and discontinuation. This systematic analysis of the current literature delineates treatment options for unscheduled bleeding related to LARC use. Although consistent results are lacking, all devices seem to have the best response to nonsteroidal antiinflammatory drugs for 5 to 7 days or the antifibrinolytic agent tranexamic acid. Additional studies are necessary to identify improved treatment interventions for unscheduled bleeding with LARC use.

  5. [Guidelines on long-acting injectable atypical antipsychotics for first-episode schizophrenia].

    PubMed

    Azorin, J-M

    2013-09-01

    The current review raises the question of the place of long-acting injectable (LAI) atypical antipsychotics for the treatment of first-episode schizophrenia in current and future guidelines. After exposing the different points of view adopted in the former, the author presents the clinical trials conducted with LAI atypicals in this indication, as well as the surveys related to psychiatrists'opinion regarding the use of these drugs in early schizophrenia. Pros and cons of this therapeutic option are discussed and suggestions are made for further guidelines.

  6. A review of the effects of long-acting progestogen-only contraceptives on ovarian activity.

    PubMed

    Li, X F; Davies, G C; Newton, J

    1992-03-01

    Progestogen-only contraception acts mainly by blocking cervical mucus and preventing sperm penetration through it does have a variable pattern of contraceptive effects on the endometrium and ovary. In contrast with the complete suppression of ovarian function with combined pill or injectable use, a variable degree of endocrine activity is demonstrated in women choosing a long-acting progestogen-only contraceptive. This degree of suppression of ovarian activity explains the decrease in systemic side-effects, the rapid resumption of ovulation and recovery of fertility following the discontinuation of the method. New delivery systems of progestogens, the vaginal ring and implant, offer better and more consistent contraceptive effects.

  7. Method for sizing hollow microspheres

    DOEpatents

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  8. Docetaxel-loaded PLGA and PLGA-PEG nanoparticles for intravenous application: pharmacokinetics and biodistribution profile

    PubMed Central

    Rafiei, Pedram; Haddadi, Azita

    2017-01-01

    Docetaxel is a highly potent anticancer agent being used in a wide spectrum of cancer types. There are important matters of concern regarding the drug’s pharmacokinetics related to the conventional formulation. Poly(lactide-co-glycolide) (PLGA) is a biocompatible/biodegradable polymer with variable physicochemical characteristics, and its application in human has been approved by the United States Food and Drug Administration. PLGA gives polymeric nanoparticles with unique drug delivery characteristics. The application of PLGA nanoparticles (NPs) as intravenous (IV) sustained-release delivery vehicles for docetaxel can favorably modify pharmacokinetics, biofate, and pharmacotherapy of the drug in cancer patients. Surface modification of PLGA NPs with poly(ethylene glycol) (PEG) can further enhance NPs’ long-circulating properties. Herein, an optimized fabrication approach has been used for the preparation of PLGA and PLGA–PEG NPs loaded with docetaxel for IV application. Both types of NP formulations demonstrated in vitro characteristics that were considered suitable for IV administration (with long-circulating sustained-release purposes). NP formulations were IV administered to an animal model, and docetaxel’s pharmacokinetic and biodistribution profiles were determined and compared between study groups. PLGA and PEGylated PLGA NPs were able to modify the pharmacokinetics and biodistribution of docetaxel. Accordingly, the mode of changes made to pharmacokinetics and biodistribution of docetaxel is attributed to the size and surface properties of NPs. NPs contributed to increased blood residence time of docetaxel fulfilling their role as long-circulating sustained-release drug delivery systems. Surface modification of NPs contributed to more pronounced docetaxel blood concentration, which confirms the role of PEG in conferring long-circulation properties to NPs. PMID:28184163

  9. Preparation, Characterization, and In Vivo Evaluation of Olanzapine Poly(D,L-lactide-co-glycolide) Microspheres

    PubMed Central

    D'Souza, Susan; Faraj, Jabar A.; Giovagnoli, Stefano; DeLuca, Patrick P.

    2013-01-01

    The aim of this study was to prepare injectable depot formulations of Olanzapine using four poly(D,L-lactide-co-glycolide) (PLGA) polymers of varying molecular weight and copolymer composition, and evaluate in vivo performance in rats. In vivo release profiles from the formulations were governed chiefly by polymer molecular weight and to a lesser extent, copolymer composition. Formulations A and B, manufactured using low molecular weight PLGA and administered at 10 mg/kg dose, released drug within 15 days. Formulation C, prepared from intermediate molecular weight PLGA and administered at 20 mg/kg dose, released drug in 30 days, while Formulation D, manufactured using a high molecular weight polymer and administered at 20 mg/kg dose, released drug in 45 days. A simulation of multiple dosing at 7- and 10-day intervals for Formulations A and B revealed that steady state was achieved within 7–21 days and 10–30 days, respectively. Similarly, simulations at 15-day intervals for Formulations C and D indicated that steady state levels were reached during days 15–45. Overall, steady state levels for 7-, 10-, or 15-day dosing ranged between 45 and 65 ng/mL for all the formulations, implying that Olanzapine PLGA microspheres can be tailored to treat patients with varying clinical needs. PMID:26555996

  10. Microsphere-Based Scaffolds Encapsulating Tricalcium Phosphate And Hydroxyapatite For Bone Regeneration

    PubMed Central

    Gupta, Vineet; Lyne, Dina V.; Barragan, Marilyn; Berkland, Cory J.; Detamore, Michael S.

    2016-01-01

    Bioceramic mixtures of tricalcium phosphate (TCP) and hydroxyapatite (HAp) are widely used for bone regeneration because of their excellent cytocompatibility, osteoconduction, and osteoinduction. Therefore, we hypothesized that incorporation of a mixture of TCP and HAp in microsphere-based scaffolds would enhance osteogenesis of rat bone marrow stromal cells (rBMSCs) compared to a positive control of scaffolds with encapsulated bone-morphogenic protein-2 (BMP-2). Poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds encapsulating TCP and HAp mixtures in two different ratios (7:3 and 1:1) were fabricated with the same net ceramic content (30 wt%) to evaluate how incorporation of these ceramic mixtures would affect the osteogenesis in rBMSCs. Encapsulation of TCP/HAp mixtures impacted microsphere morphologies and the compressive moduli of the scaffolds. Additionally, TCP/HAp mixtures enhanced the end-point secretion of extracellular matrix (ECM) components relevant to bone tissue compared to the “blank” (PLGA-only) microsphere-based scaffolds as evidenced by the biochemical, gene expression, histology, and immunohistochemical characterization. Moreover, the TCP/HAp mixture groups even surpassed the BMP-2 positive control group in some instances in terms of matrix synthesis and gene expression. Lastly, gene expression data suggested that the rBMSCs responded differently to different TCP/HAp ratios presented to them. Altogether, it can be concluded that TCP/HAp mixtures stimulated the differentiation of rBMSCs toward an osteoblastic phenotype, and therefore may be beneficial in gradient microsphere-based scaffolds for osteochondral regeneration. PMID:27272903

  11. The effect of porosity on drug release kinetics from vancomycin microsphere/calcium phosphate cement composites.

    PubMed

    Schnieders, Julia; Gbureck, Uwe; Vorndran, Elke; Schossig, Michael; Kissel, Thomas

    2011-11-01

    The influence of porosity on release profiles of antibiotics from calcium phosphate composites was investigated to optimize the duration of treatment. We hypothesized, that by the encapsulation of vancomycin-HCl into biodegradable microspheres prior admixing to calcium phosphate bone cement, the influence of porosity of the cement matrix on vancomycin release could be reduced. Encapsulation of vancomycin into a biodegradable poly(lactic co-glycolic acid) copolymer (PLGA) was performed by spray drying; drug-loaded microparticles were added to calcium phosphate cement (CPC) at different powder to liquid ratios (P/L), resulting in different porosities of the cement composites. The effect of differences in P/L ratio on drug release kinetics was compared for both the direct addition of vancomycin-HCl to the cement liquid and for cement composites modified with vancomycin-HCl-loaded microspheres. Scanning electron microscopy (SEM) was used to visualize surface and cross section morphology of the different composites. Brunauer, Emmett, and Teller-plots (BET) was used to determine the specific surface area and pore size distribution of these matrices. It could be clearly shown, that variations in P/L ratio influenced both the porosity of cement and vancomycin release profiles. Antibiotic activity during release study was successfully measured using an agar diffusion assay. However, vancomycin-HCl encapsulation into PLGA polymer microspheres decreased porosity influence of cement on drug release while maintaining antibiotic activity of the embedded substance.

  12. Surface-modified PLGA nanosphere with chitosan improved pulmonary delivery of calcitonin by mucoadhesion and opening of the intercellular tight junctions.

    PubMed

    Yamamoto, Hiromitsu; Kuno, Yoshio; Sugimoto, Shohei; Takeuchi, Hirofumi; Kawashima, Yoshiaki

    2005-02-02

    Surface-modified DL-lactide/glycolide copolymer (PLGA) nanospheres with chitosan (CS) were prepared by the emulsion solvent diffusion method for pulmonary delivery of peptide, i.e., elcatonin. The nanosphere suspension was successfully aerosolized with a nebulizer similar to the drug solution, whereas the microsphere suspensions could not be aerosolized. After pulmonary administration, CS-modified PLGA nanospheres were more slowly eliminated from the lungs than unmodified PLGA nanospheres. CS-modified PLGA nanospheres loaded with elcatonin reduced blood calcium levels to 80% of the initial calcium concentration and prolonged the pharmacological action to 24 h, which was a significantly longer duration of action than that by CS-unmodified nanospheres. These results were attributed to the retention of nanospheres adhered to the bronchial mucus and lung tissue and sustained drug release at the adherence site. In addition, CS and CS on the surface of the nanospheres enhanced the absorption of drug. The rank order of the absorption of the model drugs with CS solution was carboxyfluorescein>FITC-dextran-4 (FD-4; Mw. 4000)>FD-21 (Mw. 21,000)>FD70 (Mw. 70,000), which corresponded to the molecular weights ([Mw.] given in parentheses). The absorption-enhancing effect may have been caused by opening the intercellular tight junctions.

  13. Controlled release of the fibronectin central cell binding domain from polymeric microspheres.

    PubMed

    Bouissou, Camille; Potter, Ursula; Altroff, Harri; Mardon, Helen; Van Der Walle, Christopher

    2004-03-24

    Non-ionic surfactants have been employed as alternatives to PVA for the emulsification-encapsulation of a conformationally labile protein (FIII9'-10) into PLGA microspheres. FIII9'-10 was encapsulated using a w/o/w double emulsification-evaporation technique and the microspheres fabricated were characterized by SEM and CLSM. The peptide backbone integrity of FIII9'-10 was assayed by SDS-PAGE and the degree of unfolding of FIII9'-10 following emulsification-encapsulation was assessed using a fibroblast cell-attachment assay. The encapsulation efficiency for FIII9'-10 was 25% when using PVA, compared to 50-60% when using Igepal CA-630 or Triton-X100, with values below for the other surfactants. FIII9'-10 released from microspheres promoted cell attachment in a concentration-dependent manner, only Igepal CA-630 and Triton X-100 maintaining near-maximal cell attachment, indicating that the conformation of the relatively unstable FIII9' domain was preserved. All non-ionic surfactants reduced microsphere surface porosity, compared to PVA, and an increasing surface rugosity (leading to minor 'ridges') could be correlated with decreasing surfactant HLB. Low surface porosities did not effect the diffusion of FIII9'-10 from the microspheres' internal pores in a 'burst release', as may have been imagined. In summary, non-ionic surfactants should be considered over PVA for the maintenance of biological activity of conformationally labile proteins during encapsulation.

  14. Cost and carbon burden of long-acting injections: a sustainable evaluation

    PubMed Central

    Maughan, Daniel L.; Lillywhite, Rob; Cooke, Matthew

    2016-01-01

    Aims and method This study explores the economic cost and carbon footprint associated with current patterns of prescribing long-term flupentixol decanoate long-acting injections. We conducted an analysis of prescription data from a mental health trust followed by economic and carbon cost projections using local and national data. Results A reduction of £300 000 could be achieved across England by improving prescribing behaviour, which equates to £250 per patient per year and 170 000 kg CO2e. These savings are unlikely to be released as cash from the service, but will lead to higher-value service provision at the same or lower cost. Most of these carbon emissions are attributable to the carbon footprint of the appointment – 88 000 kg CO2e (including energy use and materials used) and the overprescribing of medication – 66 000 kg CO2e. Clinical implications Psychiatrists need to review their prescribing practice of long-acting injections to reduce their impact on the National Health Service financial budget and the environment. PMID:27280033

  15. Pharmacokinetic study of an injectable long-acting parenteral formulation of doxycycline hyclate in calves.

    PubMed

    Vargas-Estrada, D; Gracia-Mora, J; Sumano, H

    2008-06-01

    Doxycycline hyclate (DOX-h) can be regarded as a time-dependant antibacterial. Hence, a parenteral long-acting formulation may be regarded as more pharmacologically sound. A poloxamer-based matrix was used to produce a long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its s.c. injection to calves. Serum concentrations profiles for such a prepartion were compared to the corresponding profiles obtained with an aqueous formulation of DOX-h injected either i.m. or i.v. in 10 calves in a crossover study at dose of 10mg/kg, with washout periods. DOX-h-LA showed the greatest values for bioavailability (602%); maximum serum concentration (C(max)) value was 1.99microg/mL with a time to reach C(max) (T(max)) of 25h and an elimination half-life of 40.81h. Considering minimum effective serum concentration of 0.5microg/mL a dose-interval of 80h can be achieved for DOX-h-LA, and only 9.7h and 17h after the i.v. or i.m. administration of DOX-h, respectively.

  16. Adjunctive and Long-Acting Nanoformulated Antiretroviral Therapies for HIV-associated neurocognitive disorders

    PubMed Central

    Gendelman, Howard E.; Gelbard, Harris A.

    2014-01-01

    Purpose of review This review focuses on current and future strategies to modulate neuroinflammation while reducing residual viral burden in the central nervous system (CNS). This has been realized by targeted long acting antiretroviral nano- and adjunctive therapies being developed for HIV infected people. Our ultimate goal is to eliminate virus from its CNS reservoirs and, in so doing, reverse the cognitive and motor dysfunctions seen in HIV-associated neurocognitive disorders (HAND). Recent findings Herein, we highlight our laboratories development of adjunctive and nanomedicine therapies for HAND. An emphasis is placed on drug-drug interactions that target both the viral life cycle and secretory pro-inflammatory neurotoxic factors and signaling pathways. Summary Antiretroviral therapy (ART) has improved the quality and duration of life for people living with HIV-1. A significant long-term comorbid illness is HAND. Symptoms, while reduced in severity, are common. Disease occurs, in part, through continued low-level viral replication inducing secondary glial neuroinflammatory activities. Our recent works and those of others have seen disease attenuated in animal models through the use of adjunctive and long-acting reservoir targeted nanoformulated ART. The translation of these inventions from animals to humans is the focus of this review. PMID:25226025

  17. A long-acting GH receptor antagonist through fusion to GH binding protein

    PubMed Central

    Wilkinson, Ian R.; Pradhananga, Sarbendra L.; Speak, Rowena; Artymiuk, Peter J.; Sayers, Jon R.; Ross, Richard J.

    2016-01-01

    Acromegaly is a human disease of growth hormone (GH) excess with considerable morbidity and increased mortality. Somatostatin analogues are first line medical treatment but the disease remains uncontrolled in up to 40% of patients. GH receptor (GHR) antagonist therapy is more effective but requires frequent high-dose injections. We have developed an alternative technology for generating a long acting potent GHR antagonist through translational fusion of a mutated GH linked to GH binding protein and tested three candidate molecules. All molecules had the amino acid change (G120R), creating a competitive GHR antagonist and we tested the hypothesis that an amino acid change in the GH binding domain (W104A) would increase biological activity. All were antagonists in bioassays. In rats all antagonists had terminal half-lives >20 hours. After subcutaneous administration in rabbits one variant displayed a terminal half-life of 40.5 hours. A single subcutaneous injection of the same variant in rabbits resulted in a 14% fall in IGF-I over 7 days. In conclusion: we provide proof of concept that a fusion of GHR antagonist to its binding protein generates a long acting GHR antagonist and we confirmed that introducing the W104A amino acid change in the GH binding domain enhances antagonist activity. PMID:27731358

  18. The effect of long-acting reversible contraception on rapid repeat pregnancy in adolescents: a review.

    PubMed

    Baldwin, Maureen K; Edelman, Alison B

    2013-04-01

    Repeat pregnancy within 2 years of a previous birth or abortion occurs in approximately 35% of recently pregnant female adolescents. The majority of these pregnancies are classified as unintended with about half ending in births and the remainder in abortions. Rapid repeat pregnancy (RRP) is associated with increased maternal and neonatal morbidity and continues a cycle of economic deprivation for young women and their families. Immediately following a pregnancy, most young women report an intention to avoid pregnancy in the near future, but many change their minds or become ambivalent within months. Lack of contraceptive use is more common among those teens that resume sexual intercourse earlier, live with a male partner, had a preterm delivery, or had an intended teen pregnancy. Adolescents who do not initiate a long-acting reversible contraceptive (LARC) method (intrauterine device or contraceptive implant) have up to a 35 times increased risk of RRP compared with their peers using LARC. Risk of RRP is decreased when LARC methods are initiated earlier after an abortion or within the postpartum period. This review will focus on the prevalence of RRP, the risk factors for RRP, and the effectiveness of strategies to reduce unintended RRP including counseling and early initiation of long-acting contraceptive methods.

  19. Long-acting injectable formulations of new-generation antipsychotics: a review from a clinical perspective.

    PubMed

    Rauch, Anna-Sophia; Fleischhacker, W Wolfgang

    2013-08-01

    Antipsychotics are the mainstay of the long-term treatment of patients with schizophrenia. In this context, the evidence also supports the effectiveness of long-acting injections (LAIs) or depots of antipsychotics regarding their relapse-preventing properties. When a LAI formulation of risperidone was launched as the first second-generation depot, there was a renaissance of interest in these formulations. In the meantime, olanzapine, paliperidone, and aripiprazole have been approved by regulatory authorities as LAIs in various countries. All studies using the new-generation depots have shown a clear advantage over placebo regarding relapse prevention and symptom reduction. Safety profiles of the long-acting compounds are comparable to their oral formulations with the exception of olanzapine pamoate injections, which can sometimes lead to a post-injection delirium. Despite the fact that many treatment guidelines recommend LAI antipsychotics as an important treatment option for the long-term management of schizophrenia, they are still most frequently used in chronically ill patients with considerable compliance problems. It is imperative to overcome this indication bias in order to be able to utilize all available treatment options in the long-term management of schizophrenia. There is little evidence on comparisons between LAIs and their oral mother compounds, and even less concerning effectiveness comparisons between different depots. The purpose of this manuscript is to review the recent clinical evidence on new-generation depot antipsychotics.

  20. Second-generation long-acting injectable antipsychotic agents: an overview.

    PubMed

    2012-09-01

    For over 40 years, antipsychotic drugs have been used as long-term maintenance treatment to control symptoms and reduce relapse rates in patients with schizophrenia. 'First-generation' oral agents such as haloperidol and chlorpromazine are associated with high levels of unwanted neurological effects and poor rates of patient adherence.1,2 Long-acting ('depot') injections of antipsychotics were developed to try to improve adherence. 'Second-generation' antipsychotic agents (also known as atypical antipsychotics) were introduced into clinical practice over 16 years ago. Although these agents have a lower propensity to cause extrapyramidal side effects, they are associated with a range of other unwanted effects (e.g. weight gain and its sequelae).1,3,4 Initially, second-generation agents were only available as orally administered medicines. Three long-acting injectable formulations of second-generation antipsychotics are now available in the UK: olanzapine embonate injection (ZypAdhera), paliperidone injection (Xeplion) and risperidone injection (Risperdal Consta). In this article we review the evidence for these agents and discuss the practical implications of their use.

  1. The Pharmacokinetics of Second-Generation Long-Acting Injectable Antipsychotics: Limitations of Monograph Values.

    PubMed

    Lee, Lik Hang N; Choi, Charles; Collier, Abby C; Barr, Alasdair M; Honer, William G; Procyshyn, Ric M

    2015-12-01

    Product monographs (also known by terms such as Summary of Product Characteristics and Highlights of Prescribing Information, depending on the jurisdiction) provide essential information to ensure the safe and effective use of a drug. Medical practitioners often rely on these monographs for guidance on matters related to pharmacokinetics as well as indications, contraindications, clinical pharmacology, and adverse reactions. The clinical and scientific information found within these documents, forming the basis for decision making, are presumed to be derived from well-designed studies. The objective of this review is to examine the source and validity of the pharmacokinetic data used in establishing the half-lives and times to steady-state reported in the product monographs of second-generation long-acting injectable antipsychotics. Thus, we have critically evaluated the clinical trials from which the pharmacokinetic parameters listed in the product monographs were determined. In many cases, the pharmacokinetic information presented in product monographs is of limited use to clinicians wishing to optimize the effectiveness and tolerability of second-generation long-acting injectable antipsychotics. Under such circumstances, off-label prescribing practices may actually produce better clinical outcomes than if decisions were made based on the product monographs alone.

  2. Growth Factor Gradients via Microsphere Delivery in Biopolymer Scaffolds for Osteochondral Tissue Engineering

    PubMed Central

    Wang, Xiaoqin; Wenk, Esther; Zhang, Xiaohui; Meinel, Lorenz; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2009-01-01

    Temporally and spatially controlled delivery of growth factors in polymeric scaffolds is crucial for engineering composite tissue structures, such as osteochondral constructs. In the present study, microsphere-mediated growth factor delivery in polymer scaffolds and its impact on osteochondral differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) was evaluated. Two growth factors, bone morphogenetic protein 2 (rhBMP-2) and insulin-like growth factor I (rhIGF-I), were incorporated as a single concentration gradient or reverse gradient combining two factors in the scaffolds. To assess the gradient making system and the delivery efficiency of polylactic-co-glycolic acid (PLGA) and silk fibroin microspheres, initially an alginate gel was fabricated into a cylinder shape with microspheres incorporated as gradients. Compared to PLGA microspheres, silk microspheres were more efficient in delivering rhBMP-2, probably due to sustained release of the growth factor, while less efficient in delivering rhIGF-I, likely due to loading efficiency. The growth factor gradients formed were shallow, inducing non-gradient trends in hMSC osteochondral differentiation. Aqueous-derived silk porous scaffolds were used to incorporate silk microspheres using the same gradient process. Both growth factors formed deep and linear concentration gradients in the scaffold, as shown by enzyme-linked immunosorbent assay (ELISA). After seeding with hMSCs and culturing for 5 weeks in a medium containing osteogenic and chondrogenic components, hMSCs exhibited osteogenic and chondrogenic differentiation along the concentration gradients of rhBMP-2 in the single gradient of rhBMP-2 and reverse gradient of rhBMP-2/rhIGF-I, but not the rhIGF-I gradient system, confirming that silk microspheres were more efficient in delivering rhBMP-2 than rhIGF-I for hMSCs osteochondrogenesis. This novel silk microsphere/scaffold system offers a new option for the delivery of multiple growth factors

  3. Use of long-acting risperidone in psychiatric disorders: focus on efficacy, safety and cost-effectiveness.

    PubMed

    Keith, Samuel

    2009-01-01

    Schizophrenia is a chronic disorder, usually necessitating lifelong treatment. Although atypical antipsychotic agents have improved outcomes in schizophrenia, their clinical potential remains limited by patients' nonadherence to medication. Long-acting antipsychotics were developed in the 1960s to enhance treatment adherence and simplify the medication process. However, although conventional long-acting agents assure medication delivery, they are associated with similar side effects to their oral equivalents. The need for an agent combining the advantages of a long-acting formulation with those of an atypical antipsychotic was highlighted in 1997 by the American Psychiatric Association's Practice Guideline for the Treatment of Patients with Schizophrenia. The first long-acting injectable atypical antipsychotic, long-acting risperidone (Risperdal Consta, Johnson & Johnson), has since been developed. This article discusses the efficacy, tolerability and cost-effectiveness of long-acting risperidone in schizophrenia and bipolar disorder patients, and suggests possibilities for how its role in clinical practice may change over the next 5 years.

  4. Bone Regeneration from PLGA Micro-Nanoparticles

    PubMed Central

    Ortega-Oller, Inmaculada; Padial-Molina, Miguel; Galindo-Moreno, Pablo; O'Valle, Francisco; Jódar-Reyes, Ana Belén; Peula-García, Jose Manuel

    2015-01-01

    Poly-lactic-co-glycolic acid (PLGA) is one of the most widely used synthetic polymers for development of delivery systems for drugs and therapeutic biomolecules and as component of tissue engineering applications. Its properties and versatility allow it to be a reference polymer in manufacturing of nano- and microparticles to encapsulate and deliver a wide variety of hydrophobic and hydrophilic molecules. It additionally facilitates and extends its use to encapsulate biomolecules such as proteins or nucleic acids that can be released in a controlled way. This review focuses on the use of nano/microparticles of PLGA as a delivery system of one of the most commonly used growth factors in bone tissue engineering, the bone morphogenetic protein 2 (BMP2). Thus, all the needed requirements to reach a controlled delivery of BMP2 using PLGA particles as a main component have been examined. The problems and solutions for the adequate development of this system with a great potential in cell differentiation and proliferation processes under a bone regenerative point of view are discussed. PMID:26509156

  5. The cost associated with administering risperidone long-acting injections in the Australian community

    PubMed Central

    2011-01-01

    Background Risperidone long-acting injection (LAI) is mostly administered twice weekly to people with schizophrenia by nurses at community mental health centres (CMHC) or through mobile outreach visits. This study estimates the cost of resource utilisation associated with the administration of risperidone LAI and the potential savings from substituting two-weekly injections with a longer interval product of therapeutic equivalence. Methods A survey of mental health staff overseeing the administration of risperidone LAI at 253 distinct Australian CMHCs was undertaken in November 2009. For the two-week period prior to the survey, respondents were asked questions on injection time (and related tasks) and, for mobile outreach visits, distance and time travelled as well as reduction in visits. Results were stratified by Australian Standard Geographical Classification (ASGC) region. Resource use was quantified and valued in Australian dollars. Results Results are derived from 74 CMHCs, representing approximately 26% of the national average risperidone LAI unit two-week sales. Stratified average injection time (including related tasks) for risperidone LAI ranged from 18-29 minutes, with a national average of 20.12 minutes. For mobile outreach visits, average distance per patient ranged from 19.4 to 55.5 km for One Staff Visits and 15.2 to 218.1 km for More Than One Staff Visits, and average time travelled ranged from 34.1 to 54.5 minutes for One Staff Visits and 29.2 to 136.3 minutes for More Than One Staff visits. The upper range consistently reflected greater resource utilisation in rural areas compared to urban areas. If administration of risperidone LAI had not been required, 20% fewer mobile outreach visits would have occurred. Conclusions The national average saving per two-weekly risperidone long-acting injection avoided is $75.14. In 2009 in Australia, this would have saved ~$11 million for injection administration costs alone if all patients taking two

  6. In Vitro and In Vivo preparation evaluations of bleomycin implants and microspheres Prepared with DL-poly (lactide-co-glycolide).

    PubMed

    D'Souza, R; Mutalik, S; Udupa, N

    2006-02-01

    In this investigation, poly(lactide-co-glycolide) (PLGA) gel implants and microspheric depot systems of bleomycin (BLM) were formulated and evaluated in vivo in mice bearing transplantable solid tumor (fibrosarcoma). The pharmacodynamic studies showed that both the formulations retarded tumor growth significantly (p<0.05) when compared to the control animals (without any drug treatment). Preliminary pharmacokinetic studies illustrated controlled release of the drug into the systemic circulation to elicit the anti-neoplastic action. The gel implants showed better release characteristics and greater pharmacodynamic action when compared to the microspheres, thus demonstrating the feasibility of employing biodegradable depot polymer gel matrix for chronic cancer therapy.

  7. Multifunctional PLGA particles containing poly(l-glutamic acid)-capped silver nanoparticles and ascorbic acid with simultaneous antioxidative and prolonged antimicrobial activity.

    PubMed

    Stevanović, Magdalena; Bračko, Ines; Milenković, Marina; Filipović, Nenad; Nunić, Jana; Filipič, Metka; Uskoković, Dragan P

    2014-01-01

    A water-soluble antioxidant (ascorbic acid, vitamin C) was encapsulated together with poly(l-glutamic acid)-capped silver nanoparticles (AgNpPGA) within a poly(lactide-co-glycolide) (PLGA) polymeric matrix and their synergistic effects were studied. The PLGA/AgNpPGA/ascorbic acid particles synthesized by a physicochemical method with solvent/non-solvent systems are spherical, have a mean diameter of 775 nm and a narrow size distribution with a polydispersity index of 0.158. The encapsulation efficiency of AgNpPGA/ascorbic acid within PLGA was determined to be >90%. The entire amount of encapsulated ascorbic acid was released in 68 days, and the entire amount of AgNpPGAs was released in 87 days of degradation. The influence of PLGA/AgNpPGA/ascorbic acid on cell viability, generation of reactive oxygen species (ROS) in HepG2 cells, as well as antimicrobial activity against seven different pathogens was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated good biocompatibility of these PLGA/AgNpPGA/ascorbic acid particles. We measured the kinetics of ROS formation in HepG2 cells by a DCFH-DA assay, and found that PLGA/AgNpPGA/ascorbic acid caused a significant decrease in DCF fluorescence intensity, which was 2-fold lower than that in control cells after a 5h exposure. This indicates that the PLGA/AgNpPGA/ascorbic acid microspheres either act as scavengers of intracellular ROS and/or reduce their formation. Also, the results of antimicrobial activity of PLGA/AgNpPGA/ascorbic acid obtained by the broth microdilution method showed superior and extended activity of these particles. The samples were characterized using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, zeta potential and particle size analysis. This paper presents a new approach to the treatment of infection that at the same time offers a very pronounced antioxidant effect.

  8. Method for preparing hollow metal oxide microsphere

    DOEpatents

    Schmitt, C.R.

    1974-02-12

    Hollow refractory metal oxide microspheres are prepared by impregnating resinous microspheres with a metallic compound, drying the impregnated microspheres, heating the microspheres slowly to carbonize the resin, and igniting the microspheres to remove the carbon and to produce the metal oxide. Zirconium oxide is given as an example. (Official Gazette)

  9. Glargine and detemir: Safety and efficacy profiles of the long-acting basal insulin analogs

    PubMed Central

    Poon, Kitty; King, Allen B

    2010-01-01

    Diabetes mellitus is a growing public health concern in the US and worldwide. Insulin therapy is the cornerstone of diabetes therapy, and the use of basal insulins will increase as clinicians strive to help their patients reach glycemic goals. Basal insulins have been continually improved upon over the years, and the long-acting basal insulin analogs, glargine and detemir, have many pharmacokinetic and pharmacodynamic advantages over neutral protamine Hagedorn insulin, namely, less variable absorption profiles, a less pronounced peak in effect, and a longer duration of action. Overall, glargine and detemir do not differ greatly in their safety and efficacy profiles. Major differences between the two include lower within-subject variability, lower risk of hypoglycemia, and a weight-sparing effect with insulin detemir. This review summarizes data from the key pharmacokinetic and pharmacodynamic studies, as well as clinical and observational studies to elucidate the role of each basal insulin analog in therapy. PMID:21701633

  10. Shared Decision Aids: Increasing Patient Acceptance of Long-Acting Reversible Contraception

    PubMed Central

    George, Tracy P.; DeCristofaro, Claire; Dumas, Bonnie P.; Murphy, Pamela F.

    2015-01-01

    Unintended pregnancies are an important public health issue. Long-acting reversible contraceptive methods (LARCs) are reliable, safe, highly effective methods for most women; however they are underutilized in the United States. Shared decision aids were added to usual care in five public health family planning clinics in the Southeastern United States, staffed by advance practice nurses and registered nurses. All five sites showed an increase in the use of LARCs during the time period that shared decision aids were used (results statistically significant to p < 0.001). It is important for women to make informed choices about contraception, and shared decision aids can be utilized to support this decision making. This resource has been adopted for statewide use in all public health clinics, and implications for practice suggest that the use of shared decision aids is an effective method to support informed patient decision making and acceptance of LARC methods of contraception. PMID:27417757

  11. Long-Acting Muscarinic Antagonists for Difficult-to-Treat Asthma: Emerging Evidence and Future Directions.

    PubMed

    Bulkhi, Adeeb; Tabatabaian, Farnaz; Casale, Thomas B

    2016-07-01

    Asthma is a complex disease where many patients remain symptomatic despite guideline-directed therapy. This suggests an unmet need for alternative treatment approaches. Understanding the physiological role of muscarinic receptors and the parasympathetic nervous system in the respiratory tract will provide a foundation of alternative therapeutics in asthma. Currently, several long-acting muscarinic antagonists (LAMAs) are on the market for the treatment of respiratory diseases. Many studies have shown the effectiveness of tiotropium, a LAMA, as add-on therapy in uncontrolled asthma. These studies led to FDA approval for tiotropium use in asthma. In this review, we discuss how the neurotransmitter acetylcholine itself contributes to inflammation, bronchoconstriction, and remodeling in asthma. We further describe the current clinical studies evaluating LAMAs in adult and adolescent patients with asthma, providing a comprehensive review of the current known physiological benefits of LAMAs in respiratory disease.

  12. Potential anti-obesity effects of a long-acting cocaine hydrolase.

    PubMed

    Zheng, Xirong; Deng, Jing; Zhang, Ting; Yao, Jianzhuang; Zheng, Fang; Zhan, Chang-Guo

    2016-11-25

    A long-acting cocaine hydrolase, known as CocH3-Fc(M3), engineered from human butyrylcholinesterase (BChE) was tested, in this study, for its potential anti-obesity effects. Mice on a high-fat diet gained significantly less body weight when treated weekly with 1 mg/kg CocH3-Fc(M3) compared to control mice, though their food intake was similar. There is no correlation between the average body weight and the average food intake, which is consistent with the previously reported observation in BChE knockout mice. In addition, molecular modeling was carried out to understand how ghrelin binds with CocH3, showing that ghrelin binds with CocH3 in a similar mode as ghrelin binding with wild-type human BChE. The similar binding structures explains why CocH3 and BChE have similar catalytic activity against ghrelin.

  13. The use of long-acting opioids in chronic pain management.

    PubMed

    Vallerand, April Hazard

    2003-09-01

    The consensus statement from the American Pain Society and American Academy of Pain Medicine states that the undertreatment of pain is unjustified [6]. It has been suggested that opioid therapy can be used effectively to treat noncancer pain in a subset of patients [26], and this is becoming more acceptable [3]. Providing sustained analgesia is an important aspect of therapy, and medications should be administered on an around-the-clock basis, because regular administration of doses maintains a constant level of drug in the body and helps prevent recurrence of pain. Ideal treatment for persistent pain is a long-acting opioid administered around the clock to prevent baseline pain, with the use of short-acting opioids as supplemental agents for breakthrough pain. Controlled-release formulations can lessen the inconvenience associated with around-the-clock administration of short-acting opioids. Sustained analgesia also can be achieved with transdermal fentanyl, which combines a strong opioid with a 72-hour release profile and the benefits of a parenteral route, avoiding first-pass metabolism. Controlled-release formulations of morphine and oxycodone are available in the United States, and hydromorphone preparations are being reviewed for approval. Clinical experience with these formulations and transdermal fentanyl indicates that these agents are equally effective in controlling pain. Studies have demonstrated improved quality of life with the transdermal route and with controlled-release morphine and oxycodone. Because of patch reapplication every 72 hours, the transdermal route also enhances compliance. Use of an opioid without the need for oral or intravenous administration and the opportunity to improve compliance are among the advantages of the transdermal route in clinical practice. The nurse has an important role in the management of patients receiving long-acting opioids for chronic noncancer pain, Facilitation of the conversion from short-acting to long-acting

  14. Physiologically-Based Pharmacokinetic Modelling to Inform Development of Intramuscular Long Acting Nanoformulations for HIV

    PubMed Central

    Rajoli, Rajith KR; Back, David J; Rannard, Steve; Meyers, Caren Freel; Flexner, Charles; Owen, Andrew; Siccardi, Marco

    2014-01-01

    Background and Objectives Antiretrovirals (ARVs) are currently used for the treatment and prevention of HIV infection. Poor adherence and low tolerability of some existing oral formulations can hinder their efficacy. Long-acting (LA) injectable nanoformulations could help address these complications by simplifying ARV administration. The aim of this study is to inform the optimisation of intramuscular LA formulations for eight ARVs through physiologically-based pharmacokinetic (PBPK) modelling. Methods A whole-body PBPK model was constructed using mathematical descriptions of molecular, physiological and anatomical processes defining pharmacokinetics. These models were validated against available clinical data and subsequently used to predict the pharmacokinetics of injectable LA formulations Results The predictions suggest that monthly intramuscular injections are possible for dolutegravir, efavirenz, emtricitabine, raltegravir, rilpivirine and tenofovir provided that technological challenges to control release rate can be addressed. Conclusions These data may help inform the target product profiles for LA ARV reformulation strategies. PMID:25523214

  15. The role of long-acting injectable antipsychotics in schizophrenia: a critical appraisal

    PubMed Central

    Veguilla, Miguel Ruiz; Taylor, David; Balanzá-Martinez, Vicent

    2014-01-01

    Despite their widespread use, long-acting injectable (LAI) antipsychotics (APs) are often regarded with some negativity because of the assumption of punishment, control and insufficient evolution towards psychosocial development of patients. However, LAI APs have proved effective in schizophrenia and other severe psychotic disorders because they assure stable blood levels, leading to a reduction of the risk of relapse. Therapeutic opportunities have also arisen after introduction of newer, second-generation LAI APs in recent years. Newer LAI APs are more readily dosed optimally, may be better tolerated and are better suited to integrated rehabilitation programmes. This review outlines the older and newer LAI APs available for the treatment of schizophrenia, with considerations of past and present pharmacological and therapeutic issues. Traditional, evidence-based approaches to systematic reviews and randomized clinical trials are of limited utility in this area so this paper’s blending of experimental trials with observational research is particularly appropriate and effective. PMID:25360245

  16. Reversible Contraception Update: The Importance of Long-Acting Reversible Contraception

    PubMed Central

    Mestad, Renee E.; Kenerson, Jessica; Peipert, Jeffrey F.

    2011-01-01

    The past several years have seen an expansion in contraception options. Emerging data support the use of long-acting reversible contraception (LARC) such as the intrauterine device and subdermal implant as the most effective methods of contraception with the highest continuation rates and very high levels of patient satisfaction. In addition, the appropriate target population for the use of the intrauterine device now includes nulliparous women and adolescents. When a patient considers initiating a new contraceptive method, it is important to consider the characteristics of each method, including the side effects, effectiveness, and patient acceptability. Additionally, medical comorbidities must also be evaluated prior to choosing a method. In this article, we provide a brief overview of available reversible contraceptive methods, with an emphasis on LARC. PMID:19641264

  17. Let's talk about sex (again): advancing the conversation around long-acting reversible contraception for teenagers.

    PubMed

    Satterwhite, Catherine Lindsey; Ramaswamy, Megha

    2015-11-01

    Long-acting reversible contraception (LARC) has incredible potential for decreasing teenage pregnancy rates in the USA, but use among adolescents remains low. LARC methods, including intrauterine devices and implants, are recommended as first-line choices for teenagers by multiple medical professional associations. Barriers at the system, provider and patient level persist, but new demonstration projects, in addition to provisions of the Affordable Care Act, show great promise in facilitating LARC use. A renewed national discourse should acknowledge the reality that many US teenagers have sex, that LARC is safe and effective and that LARC offers an opportunity to prevent teenage pregnancy. By encouraging widespread access and use, a large, positive impact across multiple health and economic sectors can be achieved.

  18. Barriers and Facilitators to Adolescents' Use of Long-Acting Reversible Contraceptives.

    PubMed

    Pritt, Nicole M; Norris, Alison H; Berlan, Elise D

    2017-02-01

    Most pregnancies among teenagers are unintended and many can be attributed to contraception misuse or nonuse. The etonogestrel implant and intrauterine devices, referred to as long-acting reversible contraceptives, or LARCs, are the most effective reversible contraceptive methods. These methods are safe for use by adolescents, yet the number of LARC users remains low among adolescents in the United States. In this review we examine recent literature about barriers and facilitators to LARC use among adolescent women. Factors that influence decision-making and provision are organized into 4 categories: (1) cost and clinical operations; (2) adolescent awareness and attitudes; (3) confidentiality, consent, and parental attitudes; and (4) health care provider knowledge, attitudes, and counseling. Knowledge deficits and misconceptions among adolescents and their health care providers are key barriers to adolescent LARC use.

  19. The role of long-acting injectable antipsychotics in schizophrenia: a critical appraisal.

    PubMed

    Brissos, Sofia; Veguilla, Miguel Ruiz; Taylor, David; Balanzá-Martinez, Vicent

    2014-10-01

    Despite their widespread use, long-acting injectable (LAI) antipsychotics (APs) are often regarded with some negativity because of the assumption of punishment, control and insufficient evolution towards psychosocial development of patients. However, LAI APs have proved effective in schizophrenia and other severe psychotic disorders because they assure stable blood levels, leading to a reduction of the risk of relapse. Therapeutic opportunities have also arisen after introduction of newer, second-generation LAI APs in recent years. Newer LAI APs are more readily dosed optimally, may be better tolerated and are better suited to integrated rehabilitation programmes. This review outlines the older and newer LAI APs available for the treatment of schizophrenia, with considerations of past and present pharmacological and therapeutic issues. Traditional, evidence-based approaches to systematic reviews and randomized clinical trials are of limited utility in this area so this paper's blending of experimental trials with observational research is particularly appropriate and effective.

  20. Aripiprazole long-acting injectable formulations for schizophrenia: aripiprazole monohydrate and aripiprazole lauroxil.

    PubMed

    Citrome, Leslie

    2016-01-01

    Aripiprazole monohydrate (AM) and aripiprazole lauroxil (AL) are two different long-acting injectable formulations of aripiprazole. AM 400 mg administered once monthly demonstrated efficacy in an acute, double-blind, placebo-controlled, randomized clinical trial, as well as in a double-blind, placebo-controlled, randomized-withdrawal maintenance study, and in two non-inferiority maintenance studies. AL is a prodrug of aripiprazole and available in 441 mg, 662 mg or 882 mg strengths. AL 441 mg and 882 mg administered once monthly demonstrated efficacy in an acute, double-blind, placebo-controlled, randomized clinical trial. The pharmacokinetic profile of AL also led to approval of dosing intervals of every 6 weeks for the 882 mg dose. The overall tolerability profiles of both products are consistent with what is known about oral aripiprazole.

  1. Clinicians' attitudes toward the use of long-acting injectable antipsychotics.

    PubMed

    Samalin, Ludovic; Charpeaud, Thomas; Blanc, Olivier; Heres, Stephan; Llorca, Pierre-Michel

    2013-07-01

    Depot formulations are not widely used in everyday practice. This study aimed to assess psychiatrists' attitudes toward the use of long-acting injectable (LAI) antipsychotics in schizophrenia. We interviewed 113 French psychiatrists about the factors that influenced their prescription of LAI antipsychotics. Multidimensional and cluster analyses were used to detect correlations. The most important factor against the use of LAI antipsychotics is a sufficient estimated compliance with the oral formulation. For first-generation LAI, the main factor is the risk for extrapyramidal symptoms; and for second-generation LAI, it is the unavailability of the equivalent oral formulation. Four factors incite the psychiatrists to prescribe LAI. Two different clusters of patients can also be identified. Most factors influencing the clinicians' attitudes toward the use of LAI antipsychotics are shared in many countries. Conversely, some attitudes related to organizational aspects, particularly the relevance of health care costs, may vary from one country to another.

  2. Pharmacokinetics of injectable, long-acting nevirapine for HIV prophylaxis in breastfeeding infants.

    PubMed

    Cortez, John M; Quintero, Rafaela; Moss, John A; Beliveau, Martin; Smith, Thomas J; Baum, Marc M

    2015-01-01

    Mother-to-child transmission (MTCT) of HIV-1 remains a global health problem. The World Health Organization (WHO) recommendations advise the administration of a once-daily, oral, prophylactic regimen of the nonnucleoside reverse transcriptase inhibitor nevirapine (NVP) from birth until 4 to 6 weeks of age for infants born to HIV-infected mothers in regions without access to safe and nutritionally adequate alternatives to breast milk. A critical factor driving the successful implementation of the WHO guidelines involves sustaining high adherence to the frequent dosing. With these challenges in mind, we have developed the first injectable, sustained-release NVP formulations with the goal of providing, for 6 weeks or longer, preventative plasma drug levels from a single subcutaneous administration at birth. The long-acting NVP consists of large (>50 μm), monodisperse NVP particles coated with biocompatible polymers that control the drug release kinetics. Two lead formulations exhibiting burst-free, sustained-release kinetics for up to 75 days in vitro were developed. Subsequent in vivo studies in rats demonstrated no toxicity related to the formulations. Rat plasma NVP concentrations were above the analytical assay's limit of quantification for up to 28 days. Pharmacokinetic analysis of the rat plasma NVP concentration-time data allowed absorption rate constants to be calculated. These data then were used to simulate infant NVP exposure from a single injected dose (<200 mg) of our long-acting formulations, demonstrating preliminary feasibility of the technology to maintain safe, preventative NVP plasma levels (0.2 to 3.0 μg ml(-1)) for 6 weeks or longer.

  3. Pharmacokinetics of Injectable, Long-Acting Nevirapine for HIV Prophylaxis in Breastfeeding Infants

    PubMed Central

    Cortez, John M.; Quintero, Rafaela; Moss, John A.; Beliveau, Martin; Smith, Thomas J.

    2014-01-01

    Mother-to-child transmission (MTCT) of HIV-1 remains a global health problem. The World Health Organization (WHO) recommendations advise the administration of a once-daily, oral, prophylactic regimen of the nonnucleoside reverse transcriptase inhibitor nevirapine (NVP) from birth until 4 to 6 weeks of age for infants born to HIV-infected mothers in regions without access to safe and nutritionally adequate alternatives to breast milk. A critical factor driving the successful implementation of the WHO guidelines involves sustaining high adherence to the frequent dosing. With these challenges in mind, we have developed the first injectable, sustained-release NVP formulations with the goal of providing, for 6 weeks or longer, preventative plasma drug levels from a single subcutaneous administration at birth. The long-acting NVP consists of large (>50 μm), monodisperse NVP particles coated with biocompatible polymers that control the drug release kinetics. Two lead formulations exhibiting burst-free, sustained-release kinetics for up to 75 days in vitro were developed. Subsequent in vivo studies in rats demonstrated no toxicity related to the formulations. Rat plasma NVP concentrations were above the analytical assay's limit of quantification for up to 28 days. Pharmacokinetic analysis of the rat plasma NVP concentration-time data allowed absorption rate constants to be calculated. These data then were used to simulate infant NVP exposure from a single injected dose (<200 mg) of our long-acting formulations, demonstrating preliminary feasibility of the technology to maintain safe, preventative NVP plasma levels (0.2 to 3.0 μg ml−1) for 6 weeks or longer. PMID:25313219

  4. Biocompatible riboflavin laurate long-acting injectable nanosuspensions allowing sterile filtration.

    PubMed

    Hu, Xi; Lin, Xia; Gu, Yuechen; Liu, Zitong; Tang, Yilin; Zhang, Yu; Chen, Xi; Wang, Yanjiao; Tang, Xing

    2014-08-01

    The aim of this research was to prepare biocompatible riboflavin laurate (RFL) long-acting injectable nanosuspensions for intramuscular injection with a small particle size allowing sterile filtration. RFL nanosuspensions were manufactured by a precipitation-combined high-pressure homogenization method. Three kinds of mixed stabilizers-d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as a primary stabilizer, and egg lecithin (PL-100M), Kollidon VA64, Kollidon S-630 as a secondary stabilizer, were separately applied to avoid further aggregation. In the three optimized formulations, the mean particle size of the RFL nanosuspensions was about 170 nm allowing sterilization by filtration. Results from transmission electron microscopy, differential scanning calorimeter, powder X-ray diffraction and Fourier transform infrared reflectance spectroscopy revealed that RFL existed as rod-like crystals. However, a few nano-spheres under 100 nm were found only when PL-100 was used as a secondary stabilizer, possibly due to TPGS and PL-100, which inserted into RFL during the process of crystallization and homogenization. In irritation testing, RFL long-acting injection (LAI) stabilized by TPGS and PL-100 led to mild paw-licking responses and a slight inflammatory reaction, which returned to normal by 14 d after administration. The endogenous PL-100 and nano-spheres with a small size may have contributed to the excellent biocompatibility. As a result, TPGS and PL-100 were selected as blended stabilizers to prepare the irritation-free RFL-LAI that could be sterilized by passage through a 0.22 μm millipore membrane filter.

  5. Differential pharmacology and clinical utility of long-acting bronchodilators in COPD – focus on olodaterol

    PubMed Central

    Matera, Maria Gabriella; Ora, Josuel; Cazzola, Mario

    2015-01-01

    Olodaterol (BI 1744 CL) is a novel, once-daily long-acting β2-agonist (LABA) designed with the aim of improving β2-adrenoreceptor selectivity and intrinsic activity. Phase III pivotal trials have documented that olodaterol Respimat Soft Mist inhaler 5 μg induces fast onset of bronchodilation, comparable with formoterol at day 1. Moreover, significant lung function improvements have been documented up to 48 weeks in patients with moderate to very severe chronic obstructive pulmonary disease (COPD). Olodaterol was generally well tolerated and had an acceptable cardiovascular and respiratory adverse event profile. Regrettably, the clinical development of olodaterol is however still too partial to draw any firm conclusions on the positioning of this ultra-LABA as monotherapy in the management of COPD. Waiting for further data on the impact of olodaterol on different patient-reported outcomes, which however are widely available for indacaterol, and mainly for a head-to-head comparison between these two ultra-LABAs and between olodaterol long-acting antimuscarinic antagonists other than tiotropium, we believe it is correct to follow the clinical indications of indacaterol also for olodaterol. In any case, the parallel bronchodilating modes of action of olodaterol and tiotropium make them an attractive combination in COPD. The results from the ongoing large TOviTO Phase III trial program have documented the efficacy and safety of olodaterol/tiotropium fixed-dose combination as maintenance therapy in patients with moderate to very severe COPD. In particular, olodaterol/tiotropium fixed-dose combination provides a convincing alternative for patients remaining symptomatic with olodaterol monotherapy. PMID:26676161

  6. Second-generation long-acting injectable antipsychotics in schizophrenia: patient functioning and quality of life

    PubMed Central

    Montemagni, Cristiana; Frieri, Tiziana; Rocca, Paola

    2016-01-01

    Long-acting injectable antipsychotics (LAIs) were developed to make treatment easier, improve adherence, and/or signal the clinician when nonadherence occurs. Second-generation antipsychotic LAIs (SGA-LAIs) combine the advantages of SGA with a long-acting formulation. The purpose of this review is to evaluate the available literature concerning the impact of SGA-LAIs on patient functioning and quality of life (QOL). Although several studies regarding schizophrenia patients’ functioning and QOL have been performed, the quantity of available data still varies greatly depending on the SGA-LAI under investigation. After reviewing the literature, it seems that SGA-LAIs are effective in ameliorating patient functioning and/or QOL of patients with schizophrenia, as compared with placebo. However, while methodological design controversy exists regarding the superiority of risperidone LAI versus oral antipsychotics, the significant amount of evidence in recently published research demonstrates the beneficial influence of risperidone LAI on patient functioning and QOL in stable patients and no benefit over oral treatment in unstable patients. However, the status of the research on SGA-LAIs is lacking in several aspects that may help physicians in choosing the correct drug therapy. Meaningful differences have been observed between SGA-LAIs in the onset of their clinical efficacy and in the relationships between symptoms and functioning scores. Moreover, head-to-head studies comparing the effects of SGA-LAIs on classical measures of psychopathology and functioning are available mainly on risperidone LAI, while those comparing olanzapine LAI with other SGA-LAIs are still lacking. Lastly, some data on their use, especially in first-episode or recent-onset schizophrenia and in refractory or treatment-resistant schizophrenia, is available. PMID:27143893

  7. Doped zinc oxide microspheres

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  8. Microsphere insulation systems

    NASA Technical Reports Server (NTRS)

    Allen, Mark S. (Inventor); Willen, Gary S. (Inventor); Mohling, Robert A. (Inventor)

    2005-01-01

    A new insulation system is provided that contains microspheres. This insulation system can be used to provide insulated panels and clamshells, and to insulate annular spaces around objects used to transfer, store, or transport cryogens and other temperature-sensitive materials. This insulation system provides better performance with reduced maintenance than current insulation systems.

  9. Doped zinc oxide microspheres

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  10. Polyvinyl pyridine microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1979-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  11. Polyvinyl pyridine microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1980-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  12. Biodistribution of PLGA and PLGA/chitosan nanoparticles after repeat-dose oral delivery in F344 rats for 7 days

    PubMed Central

    Navarro, Sara M; Darensbourg, Caleb; Cross, Linda; Stout, Rhett; Coulon, Diana; Astete, Carlos E; Morgan, Timothy; Sabliov, Cristina M

    2015-01-01

    Aim To quantify in vivo the biodistribution of poly(lactic-co-glycolic) acid (PLGA) and PLGA/chitosan nanoparticles (PLGA/Chi NPs) and assess if the positive charge of chitosan significantly enhances nanoparticle absorption in the GI tract. Material & methods PLGA and PLGA/Chi NPs covalently linked to tetramethylrhodamine-5-isothiocyanate (TRITC) were orally administered to F344 rats for 7 days, and the biodistribution of fluorescent NPs was analyzed in different organs. Results The highest amount of particles (% total dose/g) was detected for both treatments in the spleen, followed by intestine and kidney, and then by liver, lung, heart and brain, with no significant difference between PLGA and PLGA/Chi NPs. Conclusion Only a small percentage of orally delivered NPs was detected in the analyzed organs. The positive charge conferred by chitosan was not sufficient to improve the absorption of the PLGA/Chi NPs over that of PLGA NPs. PMID:25491670

  13. Tailoring magnetic PLGA nanoparticles suitable for doxorubicin delivery

    NASA Astrophysics Data System (ADS)

    Tansık, Gülistan; Yakar, Arzu; Gündüz, Ufuk

    2014-01-01

    One of the main problems of current cancer chemotherapy is the lack of selectivity of anti-cancer drugs to tumor cells, which leads to systemic toxicity and adverse side effects. In order to overcome these limitations, researches on controlled drug delivery systems have gained much attention. Nanoscale-based drug delivery systems provide tumor targeting. Among many types of nanocarriers, superparamagnetic nanoparticles with their biocompatible polymer coatings can be targeted to an intented site by an external magnetic field. Thus, the drug can be carried to the targeted site safely. The aim of this study is to prepare poly( dl-lactic- co-glycolic acid) (PLGA)-coated magnetic nanoparticles and load anti-cancer drug, doxorubicin to them. For this purpose, magnetite (Fe3O4) iron oxide nanoparticles were synthesized as a magnetic core material (MNP) and then coated with oleic acid. Oleic acid-coated MNP (OA-MNP) was encapsulated into PLGA. Effects of different OA-MNP/PLGA ratios on magnetite entrapment efficiency were investigated. Doxorubicin-loaded magnetic polymeric nanoparticles (DOX-PLGA-MNP) were prepared. After the characterization of prepared nanoparticles, their cytotoxic effects on MCF-7 cell line were studied. PLGA-coated magnetic nanoparticles (PLGA-MNP) had a proper size and superparamagnetic character. The highest magnetite entrapment efficiency of PLGA-MNP was estimated as 63 % at 1:8 ratio. Cytotoxicity studies of PLGA-MNP did not indicate any notable cell death between the concentration ranges of 2 and 125 μg/ml. Drug loading efficiency was estimated as 32 %, and it was observed that DOX-PLGA-MNP showed significant cytotoxicity on MCF-7 cells compared to PLGA-MNP. The results showed that prepared nanoparticles have desired size and superparamagnetic characteristics without serious toxic effects on cells. These nanoparticles may be suitable for targeted drug delivery applications.

  14. Development and characterization of sorafenib-loaded PLGA nanoparticles for the systemic treatment of liver fibrosis.

    PubMed

    Lin, Ts-Ting; Gao, Dong-Yu; Liu, Ya-Chi; Sung, Yun-Chieh; Wan, Dehui; Liu, Jia-Yu; Chiang, Tsaiyu; Wang, Liying; Chen, Yunching

    2016-01-10

    Sorafenib is a tyrosine kinase inhibitor that has recently been shown to be a potential antifibrotic agent. However, a narrow therapeutic window limits the clinical use and therapeutic efficacy of sorafenib. Herein, we have developed and optimized nanoparticle (NP) formulations prepared from a mixture of poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (PEG-PLGA) copolymers with poly(lactic-co-glycolic acid) (PLGA) for the systemic delivery of sorafenib into the fibrotic livers of CCl4-induced fibrosis mouse models. We characterized and compared the pharmaceutical and biological properties of two different PLGA nanoparticles (NPs)--PEG-PLGA NPs (PEG-PLGA/PLGA=10/0) and PEG-PLGA/PLGA NPs (PEG-PLGA/PLGA=5/5). Increasing the PLGA content in the PEG-PLGA/PLGA mixture led to increases in the particle size and drug encapsulation efficacy and a decrease in the drug release rate. Both PEG-PLGA and PEG-PLGA/PLGA NPs significantly prolonged the blood circulation of the cargo and increased the uptake by the fibrotic livers. The systemic administration of PEG-PLGA or PEG-PLGA/PLGA NPs containing sorafenib twice per week for a period of 4 weeks efficiently ameliorated liver fibrosis, as indicated by decreased α-smooth muscle actin (α-SMA) content and collagen production in the livers of CCl4-treated mice. Furthermore, sorafenib-loaded PLGA NPs significantly shrank the abnormal blood vessels and decreased microvascular density (MVD), leading to vessel normalization in the fibrotic livers. In conclusion, our results reflect the clinical potential of sorafenib-loaded PLGA NPs for the prevention and treatment of liver fibrosis.

  15. PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels for drug delivery.

    PubMed

    Cho, Hyunah; Gao, Jieming; Kwon, Glen S

    2016-10-28

    Poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles and poly(D,L-lactic-co-glycolic acid)-block-polyethylene glycol)-block-poly(D,L-lactic-co-glycolic acid) (PLGA-b-PEG-b-PLGA) sol-gels have been extensively researched for systemic and localized drug delivery applications, respectively, and they have both progressed into humans for paclitaxel, an important yet poorly water-soluble chemotherapeutic agent. In this review article, preclinical and clinical research on PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels that has focused on paclitaxel will be updated, and recent research on other poorly water-soluble anticancer agents and delivery of drug combinations (i.e. multi-drug delivery) that seeks synergistic anticancer efficacy will be summarized. PEG-b-PLA micelles are a first-generation platform for the systemic multi-delivery of poorly water soluble anticancer agents. PLGA-b-PEG-b-PLGA sol-gels are a first-generation platform for the localized multi-drug delivery of water-soluble and/or poorly water-soluble anticancer agents. In summary, PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels may safely enable pre-clinical evaluation and clinical translation of poorly water-soluble anticancer agents, especially for promising, rapidly emerging anticancer combinations.

  16. Long-acting beta-agonists: a review of formoterol safety data from asthma clinical trials.

    PubMed

    Sears, M R; Ottosson, A; Radner, F; Suissa, S

    2009-01-01

    The safety of long-acting beta(2)-agonist (LABA) treatment in asthma has been questioned following reported increased respiratory deaths when salmeterol was added to usual pharmacotherapy. The aim of this study was to examine whether asthma, cardiac or all-cause mortality and morbidity were increased with formoterol use. The analysis included all AstraZeneca randomised controlled parallel-group asthma trials of 3-12-months duration involving formoterol. Risks associated with formoterol use compared with non-LABA treatment, overall and in combination with inhaled corticosteroids (ICS), were assessed using an intention-to-treat analysis of the rates and rate ratios of deaths and serious adverse events (SAEs). The main objective of this study was to compare asthma-related mortality in patients using formoterol and those not using formoterol. There were eight asthma-related deaths (0.34 per 1,000 person-yrs) among 49,906 formoterol-randomised patients (92% using ICS), and two (0.22 per 1,000 person-yrs) among 18,098 patients (83% using ICS) not randomised to formoterol, which was nonsignificant. Asthma-related SAEs (>90% of which were hospitalisations) were significantly fewer among formoterol-randomised patients (0.75 versus 1.10%). There was no increase in asthma-related SAEs with increased daily doses of formoterol (9, 18 or 36 microg). There was no significant difference in cardiac mortality or noncardiac nonasthma-related mortality in formoterol-randomised compared to non-LABA-treated patients. All-cause mortality was similar. In the data set in which all subjects were prescribed ICS at baseline, there were seven asthma-related deaths (0.32 per 1,000 person-yrs) among 46,003 formoterol-randomised patients and one (0.14 per 1,000 person-yrs) among 13,905 patients not randomised to formoterol, which was also nonsignificant. There were few asthma-related or cardiac-related deaths among patients randomised to formoterol, and all differences were nonsignificant

  17. Long-acting beta-agonists and their association with inhaled corticosteroids in COPD.

    PubMed

    Fuso, L; Mores, N; Valente, S; Malerba, M; Montuschi, P

    2013-01-01

    Inhaled bronchodilators, including beta(2)-agonists and antimuscaric receptor antagonists, are the mainstay of pharmacotherapy in chronic obstructive pulmonary disease (COPD). The short-acting beta(2)-agonists, including salbutamol, and fenoterol, have a rapid onset of action, a bronchodilating effect for 3-6 h and are used on demand. The long-acting beta(2)-agonists (LABAs), including salmeterol and formoterol, have 12-hour duration of action and are used with a twice-daily dosing regimen for long-term COPD treatment. Unlike salmeterol, formoterol has a rapid onset of action. Pharmacological characteristics required by novel inhaled LABAs include 24 h bronchodilator effect in vivo which would make them suitable for once daily administration (ultra-LABA), high potency and selectivity for beta(2)-adrenoceptors, rapid onset of action, low oral bioavailability (< 5%) after inhalation, and high systemic clearance. Indacaterol, which has been approved for long-term treatment of COPD in Europe and in the USA, has a 24-h duration of action and a once-daily dosing regimen. Newer ultra-LABAs, including olodaterol, vilanterol, milveterol, carmoterol, and abediterol, are in development. Combination with ICS (fluticasone/salmeterol, budesonide/formoterol, beclomethasone/formoterol) appears to provide an additional benefit over the monocomponent therapy, although the extent of this benefit is variable and often not clinically significant in all the endpoints assessed. In patients with COPD, treatment with ICS is associated with increased risk of pneumonia which should be carefully considered when assessing the risk/benefit ratio of ICS/LABA combinations. Subphenotyping of patients with COPD (e.g., frequent exacerbations, sputum eosinophilia, mixed asthma/COPD phenotype) might help identify those patients who are most likely to benefit from addition of ICS to bronchodilating treatment. Ultra-LABA/ long-acting muscarinic receptor antagonist (LAMA) combination treatment is under

  18. “Set it and forget it”: Women’s perceptions and opinions of long-acting topical vaginal gels

    PubMed Central

    van den Berg, Jacob J.; Rosen, Rochelle K.; Bregman, Dana E.; Thompson, Lara A.; Jensen, Kathleen M.; Kiser, Patrick F.; Katz, David F.; Buckheit, Karen; Buckheit, Robert W.; Morrow, Kathleen M.

    2014-01-01

    Women’s initial understandings and anticipated acceptability of long-acting vaginal gels as potential anti-HIV microbicides was investigated by exploring the perceptibility variables associated with prototype formulations. Four focus groups with 29 women, aged 18–45, were conducted to consider gel prototypes with varied physicochemical and rheological properties. Participants responded favorably to the concept of long-acting vaginal gels as microbicides. Distinctions in understandings and stated needs regarding product dosing, characteristics, and effectiveness offer valuable insights into product design. Long-acting vaginal gels capable of protecting against HIV/STIs will be a viable option among potential users, with dosing frequency being an important factor in willingness to use. PMID:24248674

  19. Porous microsphere and its applications

    PubMed Central

    Cai, Yunpeng; Chen, Yinghui; Hong, Xiaoyun; Liu, Zhenguo; Yuan, Weien

    2013-01-01

    Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies. PMID:23515359

  20. Effects of Nano-hydroxyapatite/Poly(DL-lactic-co-glycolic acid) Microsphere-Based Composite Scaffolds on Repair of Bone Defects: Evaluating the Role of Nano-hydroxyapatite Content.

    PubMed

    He, Shu; Lin, Kai-Feng; Sun, Zhen; Song, Yue; Zhao, Yi-Nan; Wang, Zheng; Bi, Long; Liu, Jian

    2016-07-01

    The aim of the current study was to prepare microsphere-based composite scaffolds made of nano-hydroxyapatite (nHA)/poly (DL-lactic-co-glycolic acid) (PLGA) at different ratios and evaluate the effects of nHA on the characteristics of scaffolds for tissue engineering application. First, microsphere-based composite scaffolds made of two ratios of nHA/PLGA (nHA/PLGA = 20/80 and nHA/PLGA = 50/50) were prepared. Then, the effects of nHA on the wettability, mechanical strength, and degradation of scaffolds were investigated. Second, the biocompatibility and osteoinductivity were evaluated and compared by co-culture of scaffolds with bone marrow stromal stem cells (BMSCs). The results showed that the adhesion, proliferation, and osteogenic differentiation of BMSCs with nHA/PLGA (50/50) were better than those with nHA/PLGA (20/80). Finally, we implanted the scaffolds into femur bone defects in a rabbit model, then the capacity of guiding bone regeneration as well as the in vivo degradation were observed by micro-CT and histological examinations. After 4 weeks' implantation, there was no significant difference on the repair of bone defects. However, after 8 and 12 weeks' implantation, the nHA/PLGA (20/80) exhibited better bone formation than nHA/PLGA (50/50). These results suggested that a proper concentration of nHA in the nHA/PLGA composite should be taken into account when the composite scaffolds were prepared, which plays an important role in the biocompatibility, degradation rate and osteoconductivity.

  1. Global trends in use of long-acting reversible and permanent methods of contraception: Seeking a balance.

    PubMed

    Joshi, Ritu; Khadilkar, Suvarna; Patel, Madhuri

    2015-10-01

    The global trend shows that the use of permanent contraception to prevent unintended pregnancy is high. Although the trend also shows a rise in the use of long-acting reversible methods, these are still underutilized despite having contraceptive as well as non-contraceptive benefits. Lack of knowledge among women, dependence on the provider for information, and provider bias for permanent contraception are cited as reasons for this reduced uptake. Training of healthcare providers and increased patient awareness about the effectiveness of long-acting reversible contraceptive methods will increase their uptake and help prevent unintended pregnancies.

  2. Contraceptive implants: long acting and provider dependent contraception raises concerns about freedom of choice.

    PubMed Central

    Thompson, M. S.

    1996-01-01

    David Bromham's editorial on contraceptive implants ignores the wider issues to voice concern that trial by media could limit contraceptive choice by jeopardising research into new methods. However, it is more beneficial to the public for points of conflict to be debated openly. Furthermore, the impetus for research into new contraceptive technology is driven by profit and political motives and is only marginally affected by the media. Implanted contraceptives may increase the choice of contraceptive methods, but they put control of fertility increasingly into the hands of the medical profession. Herein lies their greatest problem: their potential to increase providers' control over clients' choice. There is the danger that certain groups of women may be targeted for their use: in the United States the coercive use of Norplant for mothers receiving welfare benefit has been suggested. Long acting contraceptives are a contraceptive of choice only when they are available without pressure, as part of a wider menu; when instant removal on request is guaranteed; and when there is an open and free flow of information and opinions between users, health professionals, and special interest groups. Images p1394-a PMID:8956712

  3. The use of academic detailing to improve evidence based prescribing of risperidone long acting injection.

    PubMed

    Paton, Carol; Adebowale, Olubunmi; Okocha, Chike I

    2008-01-01

    Objective. It takes 6 weeks for plasma levels of risperidone long-acting injection (RLAI) to reach steady state, and randomised controlled trials demonstrate a flat dose-response curve. In clinical practice, the dose of RLAI is often increased rapidly at the start of treatment and many patients receive a dose above 25 mg/2 weeks. We sought to understand why and to use academic detailing as a catalyst for change. Method. (1) Semi-structured interview of and academic detailing visit to psychiatrists. (2) Number of pharmacy issues or each strength of RLAI issues before and after the academic detailing visit. Results. Understanding of the pharmacokinetics of RLAI and the flat dose-response curve were poor. After a single visit from an academic detailer, the proportion of 50-mg doses issued decreased from 44 to 31%. Conclusion. Academic detailing was effective in changing prescribing practice; patients are likely to benefit through receiving treatment that has a better risk-benefit ratio, and the healthcare organization is likely to benefit, in terms of more cost-effective prescribing.

  4. Clinical Decision-Making in the Treatment of Schizophrenia: Focus on Long-Acting Injectable Antipsychotics

    PubMed Central

    Samalin, Ludovic; Garnier, Marion; Auclair, Candy; Llorca, Pierre-Michel

    2016-01-01

    The purpose of this study was to identify clinician characteristics associated with higher prescription rates of long-acting injectable (LAI) antipsychotics, as well as the sources that influence medical decision-making regarding the treatment of schizophrenia. We surveyed 202 psychiatrists during six regional French conferences (Bordeaux, Lyon, Marseille, Nice, Paris, and Strasbourg). Data on the characteristics of practice, prescription rates of antipsychotic, and information sources about their clinical decisions were collected. Most psychiatrists used second-generation antipsychotics (SGAs), and preferentially an oral formulation, in the treatment of schizophrenia. LAI SGAs were prescribed to 30.4% of schizophrenic patients. The duration and type of practice did not influence the class or formulation of antipsychotics used. The clinicians following the higher percentage of schizophrenic patients were associated with a higher use of LAI antipsychotics and a lower use of oral SGAs. Personal experience, government regulatory approval, and guidelines for the treatment of schizophrenia were the three main contributing factors guiding clinicians’ decision-making regarding the treatment of schizophrenia. The more clinicians follow schizophrenic patients, the more they use LAI antipsychotics. The development of specialized programs with top specialists should lead to better use of LAI antipsychotics in the treatment of schizophrenia. PMID:27869767

  5. Contraception for Adolescents: Focusing on Long-Acting Reversible Contraceptives (LARC) to Improve Reproductive Health Outcomes

    PubMed Central

    Salcedo, Jennifer

    2015-01-01

    Adolescent pregnancy rates in the U.S. have reached an all-time low from their peak in the 1980s and 1990s. However, the U.S. maintains the highest rate of teenage pregnancy among developed nations. Adolescents experience higher typical use failure rates for user-dependent contraceptives compared to their adult counterparts. Long-acting reversible contraception (LARC), IUDs and implants, have failure rates that are both very low and independent of user age. In settings where the most effective methods are prioritized and access barriers are removed, the majority of adolescents initiate LARC. Use of LARC by adolescents significantly reduces rates of overall and repeat teen pregnancy. All methods of contraception are safe for use in teens, including IUDs and DMPA. Dual use of LARC and barrier methods to reduce risk of sexually transmitted infection, is the optimal contraceptive strategy for most adolescents. Adolescent access to evidence-based and confidential contraceptive services, provided in a manner that respects autonomy, is a vital public health goal. PMID:27635305

  6. Randomized Clinical Trial of Long-Acting Somatostatin for Autosomal Dominant Polycystic Kidney and Liver Disease

    PubMed Central

    Masyuk, Tetyana V.; Page, Linda J.; Kubly, Vickie J.; Bergstralh, Eric J.; Li, Xujian; Kim, Bohyun; King, Bernard F.; Glockner, James; Holmes, David R.; Rossetti, Sandro; Harris, Peter C.; LaRusso, Nicholas F.; Torres, Vicente E.

    2010-01-01

    There are no proven, effective therapies for polycystic kidney disease (PKD) or polycystic liver disease (PLD). We enrolled 42 patients with severe PLD resulting from autosomal dominant PKD (ADPKD) or autosomal dominant PLD (ADPLD) in a randomized, double-blind, placebo-controlled trial of octreotide, a long-acting somatostatin analogue. We randomly assigned 42 patients in a 2:1 ratio to octreotide LAR depot (up to 40 mg every 28 ± 5 days) or placebo for 1 year. The primary end point was percent change in liver volume from baseline to 1 year, measured by MRI. Secondary end points were changes in total kidney volume, GFR, quality of life, safety, vital signs, and clinical laboratory tests. Thirty-four patients had ADPKD, and eight had ADPLD. Liver volume decreased by 4.95% ± 6.77% in the octreotide group but remained practically unchanged (+0.92% ± 8.33%) in the placebo group (P = 0.048). Among patients with ADPKD, total kidney volume remained practically unchanged (+0.25% ± 7.53%) in the octreotide group but increased by 8.61% ± 10.07% in the placebo group (P = 0.045). Changes in GFR were similar in both groups. Octreotide was well tolerated; treated individuals reported an improved perception of bodily pain and physical activity. In summary, octreotide slowed the progressive increase in liver volume and total kidney volume, improved health perception among patients with PLD, and had an acceptable side effect profile. PMID:20431041

  7. Indications for and use of long-acting injectable antipsychotics: consideration from an inpatient setting.

    PubMed

    Kishimoto, Taishiro; Sanghani, Sohag; Russ, Mark J; Marsh, Akeem N; Morris, Joshua; Basu, Suparna; John, Majnu; Kane, John M

    2017-02-08

    Studies have examined the differences in sociodemographic/clinical characteristics between patients on long-acting injectable (LAI) versus oral medications. However, most studies did not focus specifically on patients for whom LAIs would clearly be indicated. We performed a chart review of patients with schizophrenia or schizoaffective disorder. Patients were categorized as having an 'indication for an LAI' or not on the basis of their adherence history. Patients for whom an LAI was indicated and prescribed on discharge were then compared with similar patients for whom an LAI was not prescribed. Of 305 charts reviewed, consisting of 279 unique patients, 27.2% were judged to have an indication for an LAI (n=76), but only 32.9% of these (n=25) were discharged on an LAI. In the multiregression model, being African American, residing in a psychiatric residence, having a previous history of an LAI trial, and being treated with a higher antipsychotic dose were predictive of LAI prescription. It is important to focus on the population who are not likely to receive an LAI, but who have such indications for treatment.

  8. Design and synthesis of HIV-1 protease inhibitors for a long-acting injectable drug application.

    PubMed

    Kesteleyn, Bart; Amssoms, Katie; Schepens, Wim; Hache, Geerwin; Verschueren, Wim; Van De Vreken, Wim; Rombauts, Klara; Meurs, Greet; Sterkens, Patrick; Stoops, Bart; Baert, Lieven; Austin, Nigel; Wegner, Jörg; Masungi, Chantal; Dierynck, Inge; Lundgren, Stina; Jönsson, Daniel; Parkes, Kevin; Kalayanov, Genadiy; Wallberg, Hans; Rosenquist, Asa; Samuelsson, Bertil; Van Emelen, Kristof; Thuring, Jan Willem

    2013-01-01

    The design and synthesis of novel HIV-1 protease inhibitors (PIs) (1-22), which display high potency against HIV-1 wild-type and multi-PI-resistant HIV-mutant clinical isolates, is described. Lead optimization was initiated from compound 1, a Phe-Phe hydroxyethylene peptidomimetic PI, and was directed towards the discovery of new PIs suitable for a long-acting (LA) injectable drug application. Introducing a heterocyclic 6-methoxy-3-pyridinyl or a 6-(dimethylamino)-3-pyridinyl moiety (R(3)) at the para-position of the P1' benzyl fragment generated compounds with antiviral potency in the low single digit nanomolar range. Halogenation or alkylation of the metabolic hot spots on the various aromatic rings resulted in PIs with high stability against degradation in human liver microsomes and low plasma clearance in rats. Replacing the chromanolamine moiety (R(1)) in the P2 protease binding site by a cyclopentanolamine or a cyclohexanolamine derivative provided a series of high clearance PIs (16-22) with EC(50)s on wild-type HIV-1 in the range of 0.8-1.8 nM. PIs 18 and 22, formulated as nanosuspensions, showed gradual but sustained and complete release from the injection site over two months in rats, and were therefore identified as interesting candidates for a LA injectable drug application for treating HIV/AIDS.

  9. Disposition of oxytetracycline in pigs after i.m. administration of two long-acting formulations.

    PubMed

    El Korchi, G; Prats, C; Arboix, M; Pérez, B

    2001-08-01

    Two commercially available long-acting oxytetracycline (OTC) formulations were administered by the intramuscular (i.m.) route to six healthy pigs at the recommended dose of 30 mg/kg. After 2 h the mean maximum concentration (C(max)) reached values of 8.1 +/- 2.2 and 15.4 +/- 11.1 microg/mL, respectively. These concentrations remained higher than 0.5 microg/mL for more than 5 days after drug administration. The area under the concentration time curve (AUC09 days) of each formulation was 255 +/- 76.5 and 399.2 +/- 123 microg. h/mL, respectively, and the mean residence time (MRT) was around 3 days for both formulations. No significant differences were observed between the pharmacokinetic parameters of the two formulations, showing the bioequivalence of the two formulations studied according to the criteria established by the Food and Drug Administration (FDA) and the Committee for Veterinary Medicinal Products (CVMP).

  10. Safety of long-acting beta agonists and inhaled corticosteroids in children and adolescents with asthma

    PubMed Central

    Xia, Ying; Kelton, Christina M. L.; Xue, Liang; Bian, Boyang; Wigle, Patricia R.

    2013-01-01

    The introduction of long-acting beta agonists (LABAs) was considered a major advance in bronchodilator therapy for adult, as well as pediatric, patients with asthma. However, the use of LABAs has raised safety concerns, especially the potential for severe asthma exacerbations (SAEs) resulting in hospitalizations or even death. Meanwhile, the use of inhaled corticosteroids (ICSs), a cornerstone in the treatment of mild-to-severe persistent asthma, has been associated with growth suppression in children. The purpose of this review was to identify and discuss the major published safety studies surrounding LABA, ICS, and combined LABA/ICS usage in children. By way of a critical search for influential published clinical trials, meta-analyses, and observational studies, six studies relevant to the safety of LABA monotherapy, seven studies relevant to ICS monotherapy, and four studies on the subject of LABA/ICS combination usage were identified and reviewed. Based on the reviewed literature, the controversy surrounding these anti-asthma medications was clearly exposed. On the one hand, there is some evidence that LABA monotherapy may be associated with SAEs and asthma-related death, while ICS monotherapy may be associated with a higher risk of growth suppression. On the other hand, the concurrent use of a LABA with an ICS has been associated with positive outcomes including symptom reduction and reduced rate and severity of exacerbations. Further clinical research is warranted and has been called for by the US Food and Drug Administration. PMID:25114786

  11. A long-acting GH receptor antagonist through fusion to GH binding protein.

    PubMed

    Wilkinson, Ian R; Pradhananga, Sarbendra L; Speak, Rowena; Artymiuk, Peter J; Sayers, Jon R; Ross, Richard J

    2016-10-12

    Acromegaly is a human disease of growth hormone (GH) excess with considerable morbidity and increased mortality. Somatostatin analogues are first line medical treatment but the disease remains uncontrolled in up to 40% of patients. GH receptor (GHR) antagonist therapy is more effective but requires frequent high-dose injections. We have developed an alternative technology for generating a long acting potent GHR antagonist through translational fusion of a mutated GH linked to GH binding protein and tested three candidate molecules. All molecules had the amino acid change (G120R), creating a competitive GHR antagonist and we tested the hypothesis that an amino acid change in the GH binding domain (W104A) would increase biological activity. All were antagonists in bioassays. In rats all antagonists had terminal half-lives >20 hours. After subcutaneous administration in rabbits one variant displayed a terminal half-life of 40.5 hours. A single subcutaneous injection of the same variant in rabbits resulted in a 14% fall in IGF-I over 7 days.

  12. The long-acting integrase inhibitor GSK744 protects macaques from repeated intravaginal SHIV challenge.

    PubMed

    Radzio, Jessica; Spreen, William; Yueh, Yun Lan; Mitchell, James; Jenkins, Leecresia; García-Lerma, J Gerardo; Heneine, Walid

    2015-01-14

    Daily preexposure prophylaxis (PrEP) with Truvada is a proven HIV prevention strategy; however, its effectiveness is limited by low adherence. Antiretroviral drug formulations that require infrequent dosing may increase adherence and thus PrEP effectiveness. We investigated whether monthly injections of a long-acting formulation of the HIV integrase inhibitor GSK1265744 (GSK744 LA) prevented simian/human immunodeficiency virus (SHIV) infection by vaginal challenge in macaques. Female pigtail macaques (n = 12) were exposed to intravaginal inoculations of SHIV twice a week for up to 11 weeks. Half of the animals received a GSK744 LA injection every 4 weeks, and half received placebo. GSK744 LA, at plasma concentrations achievable with quarterly injections in humans, protected all six macaques from infection. Placebo controls were all infected after a median of 4 (range, 2 to 20) vaginal challenges with SHIV. Efficacy was related to high and sustained vaginal and plasma drug concentrations that remained above the protein-adjusted 90% inhibitory concentration during the dosing cycles. These data support advancement of GSK744 LA as a potential PrEP candidate for women.

  13. Clinical Decision-Making in the Treatment of Schizophrenia: Focus on Long-Acting Injectable Antipsychotics.

    PubMed

    Samalin, Ludovic; Garnier, Marion; Auclair, Candy; Llorca, Pierre-Michel

    2016-11-19

    The purpose of this study was to identify clinician characteristics associated with higher prescription rates of long-acting injectable (LAI) antipsychotics, as well as the sources that influence medical decision-making regarding the treatment of schizophrenia. We surveyed 202 psychiatrists during six regional French conferences (Bordeaux, Lyon, Marseille, Nice, Paris, and Strasbourg). Data on the characteristics of practice, prescription rates of antipsychotic, and information sources about their clinical decisions were collected. Most psychiatrists used second-generation antipsychotics (SGAs), and preferentially an oral formulation, in the treatment of schizophrenia. LAI SGAs were prescribed to 30.4% of schizophrenic patients. The duration and type of practice did not influence the class or formulation of antipsychotics used. The clinicians following the higher percentage of schizophrenic patients were associated with a higher use of LAI antipsychotics and a lower use of oral SGAs. Personal experience, government regulatory approval, and guidelines for the treatment of schizophrenia were the three main contributing factors guiding clinicians' decision-making regarding the treatment of schizophrenia. The more clinicians follow schizophrenic patients, the more they use LAI antipsychotics. The development of specialized programs with top specialists should lead to better use of LAI antipsychotics in the treatment of schizophrenia.

  14. Pharmacodynamics of long-acting folic acid-receptor targeted ritonavir boosted atazanavir nanoformulations

    PubMed Central

    Puligujja, Pavan; Balkundi, Shantanu; Kendrick, Lindsey; Baldridge, Hannah; Hilaire, James; Bade, Aditya N.; Dash, Prasanta K.; Zhang, Gang; Poluektova, Larisa; Gorantla, Santhi; Liu, Xin-Ming; Ying, Tianlei; Feng, Yang; Wang, Yanping; Dimitrov, Dimiter S.; McMillan, JoEllyn M.; Gendelman, Howard E.

    2014-01-01

    Long-acting nanoformulated antiretroviral therapy (nanoART) that target monocyte-macrophage could improve the drug’s half-life and protein binding capacities while facilitating cell and tissue depots. To this end, ART nanoparticles that target the folic acid (FA) receptor and permit cell-based drug depots were examined using pharmacokinetic and pharmacodynamic (PD) tests. FA receptor-targeted poloxamer 407 nanocrystals, containing ritonavir-boosted atazanavir (ATV/r), significantly affected several therapeutic factors: drug bioavailability increased as much as 5 times and PD activity improved as much as 100 times. Drug particles administered to human peripheral blood lymphocyte reconstituted NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ mice and infected with HIV-1ADA at a tissue culture infective dose50 of 104 infectious viral particles/ml led to ATV/r drug concentrations that paralleled FA receptor beta staining in both the macrophage-rich parafollicular areas of spleen and lymph nodes. Drug levels were higher in these tissues than what could be achieved by either native drug or untargeted nanoART particles. The data also mirrored potent reductions in viral loads, tissue viral RNA and numbers of HIV-1p24+ cells in infected and treated animals. We conclude that FA-P407 coating of ART nanoparticles readily facilitate drug carriage and facilitate antiretroviral responses. PMID:25522973

  15. Pharmacodynamics of long-acting folic acid-receptor targeted ritonavir-boosted atazanavir nanoformulations.

    PubMed

    Puligujja, Pavan; Balkundi, Shantanu S; Kendrick, Lindsey M; Baldridge, Hannah M; Hilaire, James R; Bade, Aditya N; Dash, Prasanta K; Zhang, Gang; Poluektova, Larisa Y; Gorantla, Santhi; Liu, Xin-Ming; Ying, Tianlei; Feng, Yang; Wang, Yanping; Dimitrov, Dimiter S; McMillan, JoEllyn M; Gendelman, Howard E

    2015-02-01

    Long-acting nanoformulated antiretroviral therapy (nanoART) that targets monocyte-macrophages could improve the drug's half-life and protein-binding capacities while facilitating cell and tissue depots. To this end, ART nanoparticles that target the folic acid (FA) receptor and permit cell-based drug depots were examined using pharmacokinetic and pharmacodynamic (PD) tests. FA receptor-targeted poloxamer 407 nanocrystals, containing ritonavir-boosted atazanavir (ATV/r), significantly increased drug bioavailability and PD by five and 100 times, respectively. Drug particles administered to human peripheral blood lymphocyte reconstituted NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ mice and infected with HIV-1ADA led to ATV/r drug concentrations that paralleled FA receptor beta staining in both the macrophage-rich parafollicular areas of spleen and lymph nodes. Drug levels were higher in these tissues than what could be achieved by either native drug or untargeted nanoART particles. The data also mirrored potent reductions in viral loads, tissue viral RNA and numbers of HIV-1p24+ cells in infected and treated animals. We conclude that FA-P407 coating of ART nanoparticles readily facilitates drug carriage and antiretroviral responses.

  16. Pharmacological, pharmacokinetic, and clinical properties of benidipine hydrochloride, a novel, long-acting calcium channel blocker.

    PubMed

    Yao, Kozo; Nagashima, Ken; Miki, Hiroyuki

    2006-04-01

    Benidipine is a dihydropyridine-derived calcium channel blocker developed in Japan, with several unique mechanisms of action, that is, triple calcium channels (L, N, and T) blocking action with a membrane approach. Benidipine has relatively high vascular selectivity and is expected to show protective effects on vascular endothelial cells. Renal protective effects of benidipine also have been shown in several basic and clinical studies. Moreover, anti-oxidative action and enhancing nitric oxide production have been noted with this drug, following its cardio-protective effects in patients with ischemic heart diseases. In fact, benidipine exerted a better prognostic effect than other calcium channel blockers in the therapy for patients with vasospastic angina. In addition, benidipine showed reliable antihypertensive, renoprotective effects if used in combination with angiotensin II type 1 receptor blockers (ARBs) when adequate anti-hypertensive effects are not achieved by ARBs alone, indicating that benidipine is an useful calcium channel blocker in combination therapy for hypertension. Benidipine was launched on the Japanese market 14 years ago, but few severe side effects have been reported, suggesting that this is a drug with established safety and long-acting pharmacological effects.

  17. Cost of unintended pregnancy in Norway: a role for long-acting reversible contraception

    PubMed Central

    Henry, Nathaniel; Schlueter, Max; Lowin, Julia; Lekander, Ingrid; Filonenko, Anna; Trussell, James; Skjeldestad, Finn Egil

    2015-01-01

    Objectives The objective of this study was to quantify the cost burden of unintended pregnancies (UPs) in Norway, and to estimate the proportion of costs due to imperfect contraceptive adherence. Potential cost savings that could arise from increased uptake of long-acting reversible contraception (LARC) were also investigated. Methods An economic model was constructed to estimate the total number of UPs and associated costs in women aged 15–24 years. Adherence-related UP was estimated using ‘perfect use’ and ‘typical use’ contraceptive failure rates. Potential savings from increased use of LARC were projected by comparing current costs to projected costs following a 5% increase in LARC uptake. Results Total costs from UP in women aged 15–24 years were estimated to be 164 million Norwegian Kroner (NOK), of which 81.7% were projected to be due to imperfect contraceptive adherence. A 5% increase in LARC uptake was estimated to generate cost savings of NOK 7.2 million in this group. Conclusions The cost of UP in Norway is substantial, with a large proportion of this cost arising from imperfect contraceptive adherence. Increased LARC uptake may reduce the UP incidence and generate cost savings for both the health care payer and contraceptive user. PMID:25537792

  18. Contraception for Adolescents: Focusing on Long-Acting Reversible Contraceptives (LARC) to Improve Reproductive Health Outcomes.

    PubMed

    Kaneshiro, Bliss; Salcedo, Jennifer

    2015-03-01

    Adolescent pregnancy rates in the U.S. have reached an all-time low from their peak in the 1980s and 1990s. However, the U.S. maintains the highest rate of teenage pregnancy among developed nations. Adolescents experience higher typical use failure rates for user-dependent contraceptives compared to their adult counterparts. Long-acting reversible contraception (LARC), IUDs and implants, have failure rates that are both very low and independent of user age. In settings where the most effective methods are prioritized and access barriers are removed, the majority of adolescents initiate LARC. Use of LARC by adolescents significantly reduces rates of overall and repeat teen pregnancy. All methods of contraception are safe for use in teens, including IUDs and DMPA. Dual use of LARC and barrier methods to reduce risk of sexually transmitted infection, is the optimal contraceptive strategy for most adolescents. Adolescent access to evidence-based and confidential contraceptive services, provided in a manner that respects autonomy, is a vital public health goal.

  19. Eliminating health disparities in unintended pregnancy with long-acting reversible contraception (LARC).

    PubMed

    Parks, Caitlin; Peipert, Jeffrey F

    2016-06-01

    Significant public health disparities exist surrounding teen and unplanned pregnancy in the United States. Women of color and those with lower education and socioeconomic status are at much greater risk of unplanned pregnancy and the resulting adverse outcomes. Unplanned pregnancies reduce educational and career opportunities and may contribute to socioeconomic deprivation and widening income disparities. Long-acting reversible contraception (LARC), including intrauterine devices and implants, offer the opportunity to change the default from drifting into parenthood to planned conception. LARC methods are forgettable; once placed, they offer highly effective, long-term pregnancy prevention. Increasing evidence in the medical literature demonstrates the population benefits of use of these methods. However, barriers to more widespread use of LARC methods persist and include educational, access, and cost barriers. With increasing insurance coverage under the Affordable Care Act and more widespread, no-cost coverage of methods, more and more women are choosing intrauterine devices and the contraceptive implant. Increasing the use of highly effective contraceptive methods may provide one solution to the persistent problem of the health disparities of unplanned and teen pregnancies in the United States and improve women's and children's health.

  20. Suicide Prevention in Schizophrenia: Do Long-Acting Injectable Antipsychotics (LAIs) have a role?

    PubMed

    Pompili, Maurizio; Orsolini, Laura; Lamis, Dorian A; Goldsmith, David R; Nardella, Adele; Falcone, Giulia; Corigliano, Valentina; Luciano, Mario; Fiorillo, Andrea

    2017-02-23

    Suicide risk is a major cause of death among patients with schizophrenia. Death by suicide has been reported in approximately 5% of schizophrenia patients although such figure appears an underestimation of the problem. A number of risk factors are routinely reported as associated with suicide risk among these patients, some of which are modifiable by targeted therapeutic strategies. Clozapine is the only compound that gathered evidence as an effective treatment for reducing suicide risk in schizophrenia. Long-Acting Injectable Antipsychotics (LAIs) have a range of advantages in terms of efficacy, safety and tolerability in the treatment of schizophrenia, and one area of interest is whether LAI-treatment may decrease suicidality by indirectly acting on a range of risk factors for suicide specific to schizophrenia patients. This background encouraged the present, review of research pertaining to LAI in relation to modifiable risk factors for suicide in schizophrenia. We viewed our task as gathering, speculatingand critically appraising the available research relevant to the topic, with the aim of formulating a hypothesis to be tested with further research.

  1. Four years' experience with the TCu 220C, a long-acting multisleeved copper intrauterine device.

    PubMed

    Thiery, M; Van Der Pas, H; Van Kets, H; Boogers, W; Haspels, A; Amy J-j

    1979-01-01

    4 years of experience with the TCu 220C (901 women; 28,071 woman months of use) - a long-acting multisleeved copper IUD - are analyzed. Event rates were calculated by life-table analysis with a computer program on an IBM 370/148-OS/VS1. Net cumulative rates at 4 years were as follows: pregnancy 3.3, expulsion 5.2, removal for bleeding, pain and other medical reasons 7.7, and 4.3 respectively. The incidence of pregnancy, expulsions, and removal for bleeding/pain decreases with time. Parity influences the performance of the TCu 220C. It seems to affect the pregnancy rate only marginally, but the expulsion and removal rates (for bleeding, pain, or other medical reasons) are higher in the nulliparae, and the same trends appear to be present for women of lower age groups. The IUD insertion technique seems to be important when determining the effectiveness of the method. The expulsion rate is significantly higher when the push-in technique (without sounding) is used, and the same tendency is present for pregnancies and removals for bleeding/pain, albeit to a lesser degree. Refraining from sounding the uterus and pushing-in the TCu 220C introduces the risk of not inserting the IUD high enough into the uterine cavity and therefore increases the risk of expulsion.

  2. Subcutaneous implants for long-acting drug therapy in laboratory animals may generate unintended drug reservoirs

    PubMed Central

    Guarnieri, Michael; Tyler, Betty M.; DeTolla, Louis; Zhao, Ming; Kobrin, Barry

    2014-01-01

    Background: Long-acting therapy in laboratory animals offers advantages over the current practice of 2-3 daily drug injections. Yet little is known about the disintegration of biodegradable drug implants in rodents. Objective: Compare bioavailability of buprenorphine with the biodegradation of lipid-encapsulated subcutaneous drug pellets. Methods: Pharmacokinetic and histopathology studies were conducted in BALB/c female mice implanted with cholesterol-buprenorphine drug pellets. Results: Drug levels are below the level of detection (0.5 ng/mL plasma) within 4-5 days of implant. However, necroscopy revealed that interstitial tissues begin to seal implants within a week. Visual inspection of the implant site revealed no evidence of inflammation or edema associated with the cholesterol-drug residue. Chemical analyses demonstrated that the residues contained 10-13% of the initial opiate dose for at least two weeks post implant. Discussion: The results demonstrate that biodegradable scaffolds can become sequestered in the subcutaneous space. Conclusion: Drug implants can retain significant and unintended reservoirs of drugs. PMID:24459402

  3. Synthesis of biodegradable polymer-mesoporous silica composite microspheres for DNA prime-protein boost vaccination.

    PubMed

    Ho, Jenny; Huang, Yi; Danquah, Michael K; Wang, Huanting; Forde, Gareth M

    2010-03-18

    DNA vaccines or proteins are capable of inducing specific immunity; however, the translation to the clinic has generally been problematic, primarily due to the reduced magnitude of immune response and poor pharmacokinetics. Herein we demonstrate a composite microsphere formulation, composed of mesoporous silica spheres (MPS) and poly(D,L-lactide-co-glycolide) (PLGA), enables the controlled delivery of a prime-boost vaccine via the encapsulation of plasmid DNA (pDNA) and protein in different compartments. Method with modified dual-concentric-feeding needles attached to a 40 kHz ultrasonic atomizer was studied. These needles focus the flow of two different solutions, which passed through the ultrasonic atomizer. The process synthesis parameters, which are important to the scale-up of composite microspheres, were also studied. These parameters include polymer concentration, feed flowrate, and volumetric ratio of polymer and pDNA-PEI/MPS-BSA. This fabrication technique produced composite microspheres with mean D[4,3] ranging from 6 to 34 microm, depending upon the microsphere preparation. The resultant physical morphology of composite microspheres was largely influenced by the volumetric ratio of pDNA-PEI/MPS-BSA to polymer, and this was due to the precipitation of MPS at the surface of the microspheres. The encapsulation efficiencies were predominantly in the range of 93-98% for pDNA and 46-68% for MPS. In the in vitro studies, the pDNA and protein showed different release kinetics in a 40 day time frame. The dual-concentric-feeding in ultrasonic atomization was shown to have excellent reproducibility. It was concluded that this fabrication technique is an effective method to prepare formulations containing a heterologous prime-boost vaccine in a single delivery system.

  4. Functional magnetic microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Landel, Robert F. (Inventor)

    1981-01-01

    Functional magnetic particles are formed by dissolving a mucopolysaccharide such as chitosan in acidified aqueous solution containing a mixture of ferrous chloride and ferric chloride. As the pH of the solution is raised magnetite is formed in situ in the solution by raising the pH. The dissolved chitosan is a polyelectrolyte and forms micelles surrounding the granules at pH of 8-9. The chitosan precipitates on the granules to form microspheres containing the magnetic granules. On addition of the microspheres to waste aqueous streams containing dissolved ions, the hydroxyl and amine functionality of the chitosan forms chelates binding heavy metal cations such as lead, copper, and mercury and the chelates in turn bind anions such as nitrate, fluoride, phosphate and borate.

  5. Surface characteristics of PLA and PLGA films

    NASA Astrophysics Data System (ADS)

    Paragkumar N, Thanki; Edith, Dellacherie; Six, Jean-Luc

    2006-12-01

    Surface segregation and restructuring in polylactides (poly( D, L-lactide) and poly( L-lactide)) and poly( D,L-lactide-co-glycolide) (PLGA) films of various thicknesses were investigated using both attenuated total reflection FTIR (ATR-FTIR) and contact angle relaxation measurements. In case of poly( D,L-lactide) (DLPLA), it was observed that the surface segregation and the surface restructuring of methyl side groups are influenced by the polymer film thickness. This result has been confirmed by X-ray photoelectron spectroscopy (XPS). In the same way, PLGA thick films were also characterized by an extensive surface segregation of methyl side groups. Finally, surface restructuring was investigated by dynamic contact angle measurements and it was observed when film surface comes into contact with water. In parallel, we also found that poly( L-lactide) (PLLA) thin and clear films with thickness ˜15 μm undergo conformational changes on the surface upon solvent treatment with certain solvents. The solvent treated surface of PLLA becomes hazy and milky white and its hydrophobicity increases compared to untreated surface. FTIR spectroscopic analysis indicated that polymer chains at the surface undergo certain conformational changes upon solvent treatment. These changes are identified as the restricted motions of C-O-C segments and more intense and specific vibrations of methyl side groups. During solvent treatment, the change in water contact angle and FTIR spectrum of PLLA is well correlated.

  6. Polypyrrole-Coated Electrospun PLGA Nanofibers for Neural Tissue Applications

    PubMed Central

    Lee, Jae Young; Bashur, Chris A.; Goldstein, Aaron S.; Schmidt, Christine E.

    2009-01-01

    Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form electrically conductive nanofiber structures and to examine the combined effect of nanofiber structures and electrical stimulation. Conductive meshes were produced by growing polypyrrole (PPy) on random and aligned electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers, as confirmed by scanning electron micrographs and X-ray photon spectroscopy. PPy-PLGA electrospun meshes supported the growth and differentiation of rat pheochromocytoma 12 (PC12) cells and hippocampal neurons comparable to non-coated PLGA control meshes, suggesting that PPy-PLGA may be suitable as conductive nanofibers for neuronal tissue scaffolds. Electrical stimulation studies showed that PC12 cells, stimulated with a potential of 10 mV/cm on PPy-PLGA scaffolds, exhibited 40–50% longer neurites and 40–90% more neurite formation compared to unstimulated cells on the same scaffolds. In addition, stimulation of the cells on aligned PPy-PLGA fibers resulted in longer neurites and more neurite-bearing cells than stimulation on random PPy-PLGA fibers, suggesting a combined effect of electrical stimulation and topographical guidance and the potential use of these scaffolds for neural tissue applications. PMID:19501901

  7. Thermodynamic phase behaviour of indomethacin/PLGA formulations.

    PubMed

    Prudic, Anke; Lesniak, Anna-Katharina; Ji, Yuanhui; Sadowski, Gabriele

    2015-06-01

    In the current study, the phase behaviour of indomethacin and poly(lactic-co-glycolic acid) (PLGA) formulations was investigated as a function of the molecular weight and the copolymer composition of PLGA. The formulations were prepared by ball milling, and the phase behaviour, comprised of the glass-transition temperature of the formulations and the solubility of indomethacin in PLGA, was measured using modulated differential scanning calorimetry (mDSC). The results determined that the solubility of indomethacin in PLGA at room temperature was very low and increased with a corresponding decrease in the molecular weight of PLGA. The copolymer composition of PLGA had a minor effect on the indomethacin solubility. The effect of PLGA's molecular weight and copolymer composition on the solubility of indomethacin could be modelled using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) with a high degree of accuracy when compared with the experimental data. The glass-transition temperatures had a negative deviation from the weighted mean of the glass-transition temperatures of the pure substances, which could be described by the Kwei-equation.

  8. Development of a single-dose recombinant CAMP factor entrapping poly(lactide-co-glycolide) microspheres-based vaccine against Streptococcus agalactiae.

    PubMed

    Liu, Gang; Yin, Jinhua; Barkema, Herman W; Chen, Liben; Shahid, Muhammad; Szenci, Otto; De Buck, Jeroen; Kastelic, John P; Han, Bo

    2017-03-01

    Streptococcus agalactiae is an important contagious bovine mastitis pathogen. Although it is well controlled and even eradicated in most Northern European and North American dairy herds, the prevalence of this pathogen remains very high in China. However, research on development of a vaccine against S. agalactiae mastitis is scarce. The aims of the present study were to: (1) develop a single-dose vaccine against S. agalactiae based on poly(lactic-co-glycolic acid) (PLGA) microspheres (MS) encapsulated CAMP factor, a conserved virulent protein encoded by S. agalactiae's cfb gene; and (2) evaluate its immunogenicity and protective efficacy in a mouse model. The cfb gene was cloned and expressed in a recombinant Escherichia coli strain Trans1-T1. The CAMP factor was tested to determine a safe dose range and then encapsulated in MS of PLGA (50:50) to assess its release pattern in vitro and immune reaction in vivo. Furthermore, a mouse model and a histopathological assay were developed to evaluate bacterial burden and vaccine efficacy. In the low dosage range (<100μg), CAMP factor had no obvious toxicity in mice. The release pattern in vitro was characterized by an initial burst release (44%), followed by a sustained and slower release over 7wk. In mice immunized with either pure CAMP factor protein or PLGA-CAMP, increased antibody titers were detected in the first 2wk, whereas only PLGA-CAMP immunization induced a sustained increase of antibody titers. In mice vaccinated with PLGA-CAMP, mortality and bacteria counts were lower (compared to a control group) after S. agalactiae challenge. Additionally, no pathological lesions were detected in the vaccinated group. Therefore, PLGA-CAMP conferred protective efficacy against S. agalactiae in our mouse model, indicating its potential as a vaccine against S. agalactiae mastitis. Furthermore, the slow-release kinetics of PLGA MS warranted optimism for development of a single-dose vaccine.

  9. Preparation and characterization of protein loaded microspheres based on a hydroxylated aliphatic polyester, poly(lactic-co-hydroxymethyl glycolic acid).

    PubMed

    Ghassemi, A H; van Steenbergen, M J; Talsma, H; van Nostrum, C F; Jiskoot, W; Crommelin, D J A; Hennink, W E

    2009-08-19

    The purpose of this study was to investigate the suitability of a novel hydroxylated aliphatic polyester, poly(lactic-co-hydroxymethyl glycolic acid) (PLHMGA), as controlled release system for pharmaceutical proteins. Dextran Blue (as a macromolecular model compound) and lysozyme-loaded PLHMGA and PLGA (control formulation) microspheres were prepared by a solvent evaporation technique. The Dextran Blue and lysozyme loaded PLHMGA microspheres prepared with 10% polymer solution showed, because of a high porosity, a high burst release (35-75%) and the remaining content was released in a sustained manner for 15-20 days. The microspheres prepared with 15 and 20% polymer solution had a lower porosity and showed a pulsed release after day 8 and in 27 days they released more than 90% of Blue Dextran. The release of lysozyme was incomplete, likely due to aggregation of part of the encapsulated protein. Spectroscopic analysis of the released lysozyme indicated fully preserved secondary/tertiary structure and an enzyme activity assay showed that the specific activity of the released protein was maintained. An in vitro degradation study showed that the release of Blue Dextran and lysozyme is essentially controlled by the degradation of the microspheres. This study shows that microspheres made of the hydroxylated aliphatic polyester, poly(lactic-co-hydroxymethyl glycolic acid), are promising systems for the controlled release of pharmaceutical proteins.

  10. New approaches to antiretroviral drug delivery: challenges and opportunities associated with the use of long-acting injectable agents.

    PubMed

    Boffito, Marta; Jackson, Akil; Owen, Andrew; Becker, Stephen

    2014-01-01

    Research on improved treatment of HIV infection and pre-exposure prophylaxis continues. Poor adherence to treatment is the critical risk factor for virological failure and resistance development, and long-acting formulations of anti-HIV medications that need only infrequent dosing may facilitate long-term therapeutic responses. Importantly, long-acting formulations of therapeutic agents have been used to avoid missing doses or treatment fatigue to prescribed lifelong medications in a number of different medical fields, with demonstrable success. However, such formulations are associated with challenges, such as the prolongation of adverse events with the persistence of drug concentrations and concerns over the development of resistance as a result of selective pressure as drug concentrations decline. Furthermore, long-acting injectable formulations of antiretroviral (ARV) agents with infrequent dosing may be advantageous over daily oral drug intake to prevent transmission of HIV. However, the knowledge on protective drug concentrations and frequency of dosing is poor to date and implementation globally is challenging. Importantly, if nanoformulations of ARVs requiring lower drug doses become available globally, the potential for treatment cost reductions is high, as, especially in resource-limited settings, the active pharmaceutical ingredient accounts for the greater proportion of the total cost of the medicine. In conclusion, different long-acting ARVs are being studied in phase I/II for both the treatment and prevention of HIV infection, and research on administering these agents in combination has started.

  11. New platform for controlled and sustained delivery of the EGF receptor tyrosine kinase inhibitor AG1478 using poly(lactic-co-glycolic acid) microspheres

    PubMed Central

    Robinson, Rebecca; Bertram, James P.; Reiter, Jill L.; Lavik, Erin B.

    2015-01-01

    Inhibition of the epidermal growth factor receptor (EGFR) has been shown to reduce tumor growth and metastases and promote axon regeneration in the central nervous system. Current strategies for inhibiting EGFR include the administration of reversible or irreversible small-molecule tyrosine kinase inhibitors (TKIs). However, to be effective in vivo constant and sustained delivery is required. This study explored the feasibility of encapsulating the tyrphostin 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478) in poly(lactic-co-glycolic acid) (PLGA) microspheres to achieve sustained delivery of the TKI. We characterized microspheres prepared using three different emulsion methods: solid-in-oil-in-water, oil-in-water, and oil-in-water with co-solvent. Addition of a co-solvent increased the loading and release of AG1478, and significantly (P<0.001) decreased the size of the microspheres which facilitates administration of the spheres. On average, sustained delivery of AG1478 from microspheres was achieved for six months. However, the addition of a co-solvent prolonged release for over nine months (266 days). In addition, AG1478 retained its bioactivity upon delivery, and inhibited EGFR in both immortalized rat fibroblasts and in EGFR-amplified human carcinoma cells. These results demonstrate that AG1478 can be encapsulated in PLGA and retain bioactivity; thereby providing a new platform for controlled administration of EGFR TKIs. PMID:20055747

  12. Atypical molecular pharmacology of a new long-acting beta 2-adrenoceptor agonist, TA 2005.

    PubMed

    Voss, H P; Donnell, D; Bast, A

    1992-12-01

    The molecular pharmacology of a new putative long-acting bronchodilator TA 2005 (8-hydroxy-5-[(1R)-1-hydroxy-2-[N-[(1R)-2-(p-methoxy-phenyl)- 1-methylethyl]amino]ethyl]carbostyril hydrochloride) has been compared with that of the reference compounds isoprenaline and salbutamol in both methacholine (3 x 10(-6) M) precontracted guinea pig tracheal smooth muscle relaxation and in bovine trapezium muscle binding experiments. TA 2005 appeared very potent compared with isoprenaline and salbutamol (pD2 values of 9.29 vs. 7.65 and 7.10 respectively). For isoprenaline and salbutamol a shallow displacement curve was observed and addition of the non-hydrolysable GTP analogue guanylyl-imidodiphosphate (GppNHp) gave a rightward shift (pKd,high and pKd,low values of 7.3 and 6.1 vs. 7.0 and 5.4 respectively). For TA 2005 a steep displacement curve was found with only one binding state even without GppNHp (pKd,high value of 8.2). The long duration of action of TA 2005 might be explained by tight binding of this compound to the beta 2-adrenoceptor. The extent of tight binding for TA 2005 was extremely large. The molecular basis of the tight agonist binding phenomenon for TA 2005 seems to be of different origin than for isoprenaline. It is hypothesized that a different mechanism of activation of the beta 2-adrenoceptor may be involved for TA 2005.

  13. Long-acting Reversible Contraception for Adolescents and Young Adults: Patient and Provider Perspectives

    PubMed Central

    Kavanaugh, Megan L.; Frohwirth, Lori; Jerman, Jenna; Popkin, Ronna; Ethier, Kathleen

    2013-01-01

    Study objective To describe and explore provider- and patient-level perspectives regarding long-acting reversible contraception (LARC) for teens and young adults (ages 16-24). Methods Data collection occurred between June – December 2011. We first conducted telephone interviews with administrative directors at 20 publicly funded facilities that provide family planning services. At six of these sites, we conducted a total of six focus group discussions (FGDs) with facility staff and forty-eight in-depth interviews (IDIs) with facility clients ages 16-24. Results Staff in the FGDs did not generally equate being a teen with ineligibility for IUDs. In contrast to staff, one quarter of the young women did perceive young age as rendering them ineligible. Clients and staff agreed that the “forgettable” nature of the methods and their duration were some of LARC’s most significant advantages. They also agreed that fear of pain associated with both insertion and removal and negative side effects were disadvantages. Some aspects of IUDs and implants were perceived as advantages by some clients but disadvantages by others. Common challenges to providing LARC-specific services to younger patients included extra time required to counsel young patients about LARC methods, outdated clinic policies requiring multiple visits to obtain IUDs, and a perceived higher removal rate among young women. The most commonly cited strategy for addressing many of these challenges was securing supplementary funding to support the provision of these services to young patients. Conclusion Incorporating young women’s perspectives on LARC methods into publicly funded family planning facilities’ efforts to provide these methods to a younger population may increase their use among young women. PMID:23287602

  14. Pharmacokinetics of an injectable long-acting formulation of doxycycline hyclate in dogs.

    PubMed

    Gutiérrez, Lilia; Velasco, Zazil-Ha; Vázquez, Carlos; Vargas, Dinorah; Sumano, Héctor

    2012-06-08

    Based on its PK/PD ratios, doxycycline hyclate (DOX-h), a time-dependant antibacterial, is ideally expected to achieve both sustained plasma drug concentrations at or slightly above the MIC level for as long as possible between dosing intervals. Pursuing this end, a poloxamer-based matrix was used to produce a long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its SC injection to dogs (≤ 0.3 mL per injection site), and results compared with the oral (PO) and IV pharmacokinetics of DOX-h, prepared as tablet or as freshly made solution. A crossover (4 x 4 x 4) study design was employed with 12 Mongrel dogs, with washout periods of 21 days, and at dose of 10 mg/kg in all cases. DOX-h-LA showed the greatest values for bioavailability (199.48%); maximum serum concentration (Cmax) value was 2.8 ± 0.3 with a time to reach Cmax (Tmax) of 2.11 ± 0.12 h and an elimination half-life of 133.61 ± 6.32 h. Considering minimum effective serum concentration of 0.5 μg/mL, a dose-interval of at least 1 week h can be achieved for DOX-h-LA, and only 48 h and 24 h after the IV or PO administration of DOX-h as a solution or as tablets, respectively. A non-painful small bulge, apparently non-inflammatory could be distinguished at injection sites. These lumps dissipated completely in 30 days in all cases.

  15. Physician and patient benefit–risk preferences from two randomized long-acting injectable antipsychotic trials

    PubMed Central

    Katz, Eva G; Hauber, Brett; Gopal, Srihari; Fairchild, Angie; Pugh, Amy; Weinstein, Rachel B; Levitan, Bennett S

    2016-01-01

    Purpose To quantify clinical trial participants’ and investigators’ judgments with respect to the relative importance of efficacy and safety attributes of antipsychotic treatments for schizophrenia, and to assess the impact of formulation and adherence. Methods Discrete-choice experiment surveys were completed by patients with schizophrenia and physician investigators participating in two phase-3 clinical trials of paliperidone palmitate 3-month long-acting injectable (LAI) antipsychotic. Respondents were asked to choose between hypothetical antipsychotic profiles defined by efficacy, safety, and mode of administration. Data were analyzed using random-parameters logit and probit models. Results Patients (N=214) and physicians (N=438) preferred complete improvement in positive symptoms (severe to none) as the most important attribute, compared with improvement in any other attribute studied. Both respondents preferred 3-month and 1-month injectables to oral formulation (P<0.05), irrespective of prior adherence to oral antipsychotic treatment, with physicians showing greater preference for a 3-month over a 1-month LAI for nonadherent patients. Physicians were willing to accept treatments with reduced efficacy for patients with prior poor adherence. The maximum decrease in efficacy (95% confidence interval [CI]) that physicians would accept for switching a patient from daily oral to 3-month injectable was as follows: adherent: 9.8% (95% CI: 7.2–12.4), 20% nonadherent: 25.4% (95% CI: 21.0–29.9), and 50% nonadherent: >30%. For patients, adherent: 10.1% (95% CI: 6.1–14.1), nonadherent: the change in efficacy studied was regarded as unimportant. Conclusion Improvement in positive symptoms was the most important attribute. Patients and physicians preferred LAIs over oral antipsychotics, with physicians showing a greater preference for 3-month over 1-month LAI. Physicians and patients were willing to accept reduced efficacy in exchange for switching a patient from

  16. Pharmacokinetics, Pharmacodynamics, and Efficacy of a Novel Long-Acting Human Growth Hormone: Fc Fusion Protein.

    PubMed

    Kim, Su Jin; Kwak, Hyun-Hee; Cho, Sung Yoon; Sohn, Young Bae; Park, Sung Won; Huh, Rimm; Kim, Jinsup; Ko, Ah-Ra; Jin, Dong-Kyu

    2015-10-05

    The current recombinant human growth hormone (rhGH) therapy requires daily subcutaneous (sc) injections, which results in poor patient compliance, especially in young children. To reduce the dosing frequency, we generated a chimeric protein of rhGH and the Fc-domain of immunoglobulin G (IgG) (rhGH-Fc). The pharmacokinetics and pharmacodynamics of sc-injected rhGH-Fc were assessed in male Sprague-Dawley rats and hypophysectomized rats, respectively. A single sc injection of rhGH-Fc at a dose of 0.2 mg/kg slowly reached a Cmax of 16.80 ng/mL and remained for 7 days with a half-life of 51.1 h. Conversely, a single sc injection of rhGH 0.2 mg/kg rapidly reached a Cmax of 46.88 ng/mL and declined with a half-life of 0.55 h to baseline values in 4 h. In the efficacy study, the sc-injected rhGH-Fc induced rapid weight gain and tibial width growth at a dose of 240 μg/animal. The effect of two injections of rhGH-Fc separated by 1 week was comparable to that of the same dose of 14 daily injections of rhGH. The rhGH-Fc is a novel candidate for long-acting rhGH therapy with more convenient weekly administration, as it reduces glomerular filtration and receptor-mediated clearance while allowing for the rapid reversal of potential adverse events.

  17. Knowledge and attitudes about long-acting reversible contraception among Latina women who desire sterilization

    PubMed Central

    White, Kari; Hopkins, Kristine; Potter, Joseph E.; Grossman, Daniel

    2013-01-01

    Background There is growing interest in increasing the use of long-acting reversible contraception (LARC), and suggestions that such methods may serve as an alternative to sterilization. However, there is little information about whether women who do not want more children would be interested in using LARC methods. Methods We conducted semi-structured interviews with 120 parous Latina women in El Paso, Texas who wanted a sterilization but had not obtained one. We assessed women’s awareness of and interest in using the copper intrauterine device (IUD), levonorgestrel intrauterine system (LNG-IUS), and etonogestrel implant. Findings Overall, 51%, 23% and 47% of women reported they had heard of the copper IUD, LNG-IUS and implant, respectively. More women stated they would use the copper IUD (24%) than the LNG-IUS (14%) or implant (9%). Among women interested in LARC, the most common reasons were that, relative to their current method, LARC methods were more convenient, effective, and provided longer-term protection against pregnancy. Those who had reservations about LARC were primarily concerned with menstrual changes. Women also had concerns about side effects and the methods' effectiveness in preventing pregnancy, preferring to use a familiar method. Conclusions Although these findings indicate many Latina women in this setting do not consider LARC an alternative to sterilization, they point to an existing demand among some who wish to end childbearing. Efforts are needed to improve women’s knowledge and access to a range of methods so they can achieve their childbearing goals. PMID:23816156

  18. Relevance of dosage in adherence to treatment with long-acting anticholinergics in patients with COPD

    PubMed Central

    Izquierdo, José Luis; Paredero, José Manuel; Piedra, Raul

    2016-01-01

    Introduction The aim of this study was to assess the degree of adherence for two standard regimens for administrating anticholinergic drugs (12 and 24 hours) in patients with chronic obstruction of the airflow and to establish whether the use of a once-daily dose improves the level of treatment adherence. Methods We used long-acting anticholinergics (LAMAs) as a study variable, and included the entire health area of Castile-La Mancha, numbering 2,100,998 inhabitants, as the study population. We analyzed a total of 16,446 patients who had been prescribed a LAMA between January 1, 2013 and December 31, 2013. The follow-up period, based on a centralized system of electronic prescription management, was extended until December 2014. Results During 2013, the medication collected was 7.4%–10.7% higher than indicated by labeling. This was very similar for all LAMAs, irrespective of the patient’s sex, the molecule, the device, and the drug dosage. We did not observe seasonal variations in the consumption of LAMAs, nor did we detect differences between prescription drugs for once-daily (every 24 hours) versus twice-daily (every 12 hours) administration, between the different molecules, or between different types of inhalers for the same molecule. The results were similar in 2014. Conclusion The principal conclusion of this study is that, in an area with a centralized management system of pharmacological prescriptions, adherence to treatment with LAMAs is very high, irrespective of the molecules or inhalation device. We did not find that patients who used twice-daily medication had a lower adherence. PMID:26929614

  19. Complications and continuation rates associated with two types of long-acting contraception

    PubMed Central

    Berenson, Abbey B.; Tan, Alai; Hirth, Jacqueline M.

    2015-01-01

    Objectives To compare complication and continuation rates of the levonorgestrel intrauterine system (LNG-IUS) with the subdermal etonogestrel (ENG) implant across the US among women 15 – 44 years of age. Study Design A retrospective study of health insurance claims records from 2007–2011 identified a cohort of women who had LNG-IUS (n=79,920) or ENG implants (n=7,374) inserted and had insurance coverage for 12 months post-insertion. Claims for complications were examined 12 months after insertion, or until removal of either device within each of three age groups. Results After its introduction in 2007, the frequency of ENG implants increased each year and almost 1/3 of all insertions were in teenagers. However, among women ≤ 24 years old who had delivered an infant in the prior 8 weeks, a LNG-IUS was more likely to be inserted than an ENG implant (P < .05). The most frequent complications with both methods were related to abnormal menstruation, which was more likely to occur among ENG implant users. Overall, 83–88% of the entire sample used their chosen method for at least 12 months. The odds of continuation were similar for both methods among teenagers, but ENG implants were more likely to be removed prematurely among women 20 – 24 years old (OR 1.21, 95% CI: 1.06–1.39) and 25 – 44 years old (OR 1.49, 95% CI: 1.35–1.64). Conclusions Both of these long-acting contraceptive methods are well tolerated among women of all ages, and demonstrate high continuation rates. PMID:25555662

  20. Pharmacokinetics of Long-Acting Tenofovir Alafenamide (GS-7340) Subdermal Implant for HIV Prophylaxis

    PubMed Central

    Gunawardana, Manjula; Remedios-Chan, Mariana; Miller, Christine S.; Fanter, Rob; Yang, Flora; Marzinke, Mark A.; Hendrix, Craig W.; Beliveau, Martin; Moss, John A.; Smith, Thomas J.

    2015-01-01

    Oral or topical daily administration of antiretroviral (ARV) drugs to HIV-1-negative individuals in vulnerable populations is a promising strategy for HIV-1 prevention. Adherence to the dosing regimen has emerged as a critical factor determining efficacy outcomes of clinical trials. Because adherence to therapy is inversely related to the dosing period, sustained release or long-acting ARV formulations hold significant promise for increasing the effectiveness of HIV-1 preexposure prophylaxis (PrEP) by reducing dosing frequency. A novel, subdermal implant delivering the potent prodrug tenofovir alafenamide (TAF) with controlled, sustained, zero-order (linear) release characteristics is described. A candidate device delivering TAF at 0.92 mg day−1 in vitro was evaluated in beagle dogs over 40 days for pharmacokinetics and preliminary safety. No adverse events related to treatment with the test article were noted during the course of the study, and no significant, unusual abnormalities were observed. The implant maintained a low systemic exposure to TAF (median, 0.85 ng ml−1; interquartile range [IQR], 0.60 to 1.50 ng ml−1) and tenofovir (TFV; median, 15.0 ng ml−1; IQR, 8.8 to 23.3 ng ml−1), the product of in vivo TAF hydrolysis. High concentrations (median, 512 fmol/106 cells over the first 35 days) of the pharmacologically active metabolite, TFV diphosphate, were observed in peripheral blood mononuclear cells at levels over 30 times higher than those associated with HIV-1 PrEP efficacy in humans. Our report on the first sustained-release nucleoside reverse transcriptase inhibitor (NRTI) for systemic delivery demonstrates a successful proof of principle and holds significant promise as a candidate for HIV-1 prophylaxis in vulnerable populations. PMID:25896688

  1. Blood eosinophils and inhaled corticosteroid/long-acting β-2 agonist efficacy in COPD

    PubMed Central

    Pavord, Ian D; Lettis, Sally; Locantore, Nicholas; Pascoe, Steve; Jones, Paul W; Wedzicha, Jadwiga A; Barnes, Neil C

    2016-01-01

    Objective We performed a review of studies of fluticasone propionate (FP)/salmeterol (SAL) (combination inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA)) in patients with COPD, which measured baseline (pretreatment) blood eosinophil levels, to test whether blood eosinophil levels ≥2% were associated with a greater reduction in exacerbation rates with ICS therapy. Methods Three studies of ≥1-year duration met the inclusion criteria. Moderate and severe exacerbation rates were analysed according to baseline blood eosinophil levels (<2% vs ≥2%). At baseline, 57–75% of patients had ≥2% blood eosinophils. Changes in FEV1 and St George's Respiratory Questionnaire (SGRQ) scores were compared by eosinophil level. Results For patients with ≥2% eosinophils, FP/SAL was associated with significant reductions in exacerbation rates versus tiotropium (INSPIRE: n=719, rate ratio (RR)=0.75, 95% CI 0.60 to 0.92, p=0.006) and versus placebo (TRISTAN: n=1049, RR=0.63, 95% CI 0.50 to 0.79, p<0.001). No significant difference was seen in the <2% eosinophil subgroup in either study (INSPIRE: n=550, RR=1.18, 95% CI 0.92 to 1.51, p=0.186; TRISTAN: n=354, RR=0.99, 95% CI 0.67 to 1.47, p=0.957, respectively). In SCO30002 (n=373), no significant effects were observed (FP or FP/SAL vs placebo). No relationship was observed in any study between eosinophil subgroup and treatment effect on FEV1 and SGRQ. Discussion Baseline blood eosinophil levels may represent an informative marker for exacerbation reduction with ICS/LABA in patients with COPD and a history of moderate/severe exacerbations. PMID:26585525

  2. Effects of long-acting somatostatin analogues on redox systems in rat lens in experimental diabetes

    PubMed Central

    Kunjara, Sirilaksana; Greenbaum, A Leslie; Sochor, Milena; Flyvbjerg, Allan; Grønbaek, Henning; McLean, Patricia

    2014-01-01

    The effects of long-acting somatostatin analogues, angiopeptin (AGP) and Sandostatin (SMS), on the early decline in the lens content of glutathione (GSH), ATP and NADPH and increase in sorbitol were studied in STZ diabetic rats, and comparison was made with the effect of insulin. Three factors prompted this study: (i) the known increase in IGF-1 in ocular tissue in diabetes and antagonistic effect of somatostatins, (ii) the known effect of IGF-1 in increasing lens aldose reductase and (iii) the lack of effect of somatostatins on diabetic hyperglycaemia, the latter enabling a differentiation to be made between effects of hyperglycaemia per se and site(s) of IGF-1/somatostatins. All four metabolites studied showed a significant restoration towards the normal control level after 7 days of treatment with AGP and SMS, and AGP was more effective on levels of GSH and ATP. A significant correlation was found between GSH and ATP across all groups at 7 days treatment. The redox state changes in diabetes include both NADP+/NADPH and NAD+/NADH in the conversion of glucose to sorbitol and via sorbitol dehydrogenase to fructose with a linked decrease in ATP formation via NAD+/NADH regulation of the glycolytic pathway. The interlinked network of change includes the requirement for ATP in the synthesis of GSH. The present study points to possible loci of action of somatostatins in improving metabolic parameters in the diabetic rat lens via effects on aldose reductase and/or glucose transport at GLUT 3. PMID:24602114

  3. Combination treatment with risperidone long-acting injection and psychoeducational approaches for preventing relapse in schizophrenia.

    PubMed

    Zhao, Yueren; Kishi, Taro; Iwata, Nakao; Ikeda, Manabu

    2013-01-01

    A recent meta-analysis showed that long-acting injectable (LAI) antipsychotics were not superior to oral antipsychotics for preventing relapse in patients with schizophrenia. We therefore designed a treatment strategy combining risperidone LAI and COMPASS (COMprehensive Psycho-educational Approach and Scheme Set), an original psychoeducational program supporting treatment with risperidone LAI and evaluating subjective treatment satisfaction, transition of symptoms, and effectiveness in preventing symptomatic relapse. The aim of this study was to examine whether addition of COMPASS to risperidone LAI was more effective in preventing relapse in schizophrenia patients than risperidone LAI alone, with the latter group consisting of patients enrolled in a Phase III trial of risperidone LAI in Japan. Patients were followed up for 6 months, with COMPASS continuously implemented from the transition to the observation phase. The primary efficacy measurements were relapse rate (rates of rehospitalization and discontinuation due to inefficacy). Secondary efficacy measurements were the Brief Psychiatric Rating Scale (BPRS) and Global Assessment of Functioning (GAF) scores. Of the 96 patients originally enrolled, 19 (19.8%) were discontinued from all causes. During the 6-month study period, ten of the 96 patients (10.4%) relapsed, compared with a 12.2% relapse rate in patients enrolled in a Phase III trial of risperidone LAI in Japan. Patients showed significant improvements in BPRS total scores (P = 0.0031), BPRS positive (P = 0.0451), BRPS negative (P < 0.0001), and general subscale scores (P = 0.0031), and GAF (P < 0.0001) from baseline to 6 months. In conclusion, the lower relapse rate observed in patients treated with COMPASS plus risperidone LAI than in patients treated with risperidone LAI alone suggests that COMPASS may have benefits in the treatment of schizophrenia, indicating a need for randomized, controlled trials in larger numbers of patients.

  4. Pharmacokinetics of an injectable long-acting parenteral formulation of doxycycline hyclate in pigs.

    PubMed

    Gutiérrez, L; Ocampo, L; Espinosa, F; Sumano, H

    2014-02-01

    Based on its ideal PK/PD ratios, doxycycline hyclate (DOX-h), a time-dependant antibacterial, is ideally expected to achieve sustained plasma drug concentrations at or slightly above the MIC level for as long as possible between dosing intervals. Pursuing this end, a poloxamer-based matrix was used to produce a 10% long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its injection to pigs in the pericaudal s.c. by parallel design. Results were compared with the forced oral bolus dose and i.v. pharmacokinetics of DOX-h. For this study, 12 recently weaned pigs per group were included in this trial, and a dose of 20 mg/kg was injected in all cases. DOX-h-LA showed the greatest values for bioavailability (115.38%); maximum serum concentration (Cmax) value was 1.5 ± 0.2 with a time to reach Cmax of 3.41 ± 0.04 h and an elimination rate constant of 70.93 ± 0.87( ) h. Considering minimum effective serum concentration of 0.5 μg/mL, a dose interval of at least 5 days can be achieved for DOX-h-LA, whereas p.o. and i.v. dosing of DOX-h may only last 11 and 15 h, respectively. Pigs were slaughtered on day 30 after this trial, and no visible remnants of the preparation were detected neither fibrosis was observed after a thorough macroscopic and histopathological analysis.

  5. Efficacy and Safety of Long-Acting Reversible Contraception in Women With Cardiovascular Conditions.

    PubMed

    Vu, Quyen; Micks, Elizabeth; McCoy, Erin; Prager, Sarah

    2016-01-15

    The physiological changes that occur during pregnancy can be deleterious to women with a cardiovascular condition. Evidence-based contraceptive counseling and provision is essential in this patient population. Although long-acting reversible contraception (LARCs), which include the intrauterine device (IUD) and the etonogestrel contraceptive implant, have been found to be safe and effective in healthy women, there are inadequate data regarding LARC use in patients with cardiovascular conditions. We conducted a retrospective chart review of women diagnosed with cardiovascular disease who had a copper IUD, levonorgestrel-releasing intrauterine system or contraceptive implant placed at the University of Washington Medical Center from 2007 to 2012. We abstracted and analyzed patient demographic characteristics, medical conditions, indications for LARC placement, and complications. The sample included 470 women with cardiovascular conditions. The mean age was 34.6 years. One hundred twenty-four patients (26.11%) were nulligravid and 169 patients (35.58%) were nulliparous. Four hundred ten chose the levonorgestrel-releasing intrauterine system (87.23%), 33 patients (7.02%) opted for the copper IUD, and 23 patients (4.89%) chose the etonogestrel implant. Eighteen patients (3.83%) had a confirmed IUD expulsion, 2 patients (0.43%) became pregnant, and there were 4 cases of pelvic inflammatory disease (0.85%). There were no cases of perforation. There were no confirmed cases of infective endocarditis associated with LARC insertion. In conclusion, LARC devices appear safe with few complications for women with cardiovascular conditions. Clinicians can be reassured that LARC may be offered as an appropriate option when counseling women with cardiovascular disease on safe contraceptive methods.

  6. Pharmacokinetics of long-acting tenofovir alafenamide (GS-7340) subdermal implant for HIV prophylaxis.

    PubMed

    Gunawardana, Manjula; Remedios-Chan, Mariana; Miller, Christine S; Fanter, Rob; Yang, Flora; Marzinke, Mark A; Hendrix, Craig W; Beliveau, Martin; Moss, John A; Smith, Thomas J; Baum, Marc M

    2015-07-01

    Oral or topical daily administration of antiretroviral (ARV) drugs to HIV-1-negative individuals in vulnerable populations is a promising strategy for HIV-1 prevention. Adherence to the dosing regimen has emerged as a critical factor determining efficacy outcomes of clinical trials. Because adherence to therapy is inversely related to the dosing period, sustained release or long-acting ARV formulations hold significant promise for increasing the effectiveness of HIV-1 preexposure prophylaxis (PrEP) by reducing dosing frequency. A novel, subdermal implant delivering the potent prodrug tenofovir alafenamide (TAF) with controlled, sustained, zero-order (linear) release characteristics is described. A candidate device delivering TAF at 0.92 mg day(-1) in vitro was evaluated in beagle dogs over 40 days for pharmacokinetics and preliminary safety. No adverse events related to treatment with the test article were noted during the course of the study, and no significant, unusual abnormalities were observed. The implant maintained a low systemic exposure to TAF (median, 0.85 ng ml(-1); interquartile range [IQR], 0.60 to 1.50 ng ml(-1)) and tenofovir (TFV; median, 15.0 ng ml(-1); IQR, 8.8 to 23.3 ng ml(-1)), the product of in vivo TAF hydrolysis. High concentrations (median, 512 fmol/10(6) cells over the first 35 days) of the pharmacologically active metabolite, TFV diphosphate, were observed in peripheral blood mononuclear cells at levels over 30 times higher than those associated with HIV-1 PrEP efficacy in humans. Our report on the first sustained-release nucleoside reverse transcriptase inhibitor (NRTI) for systemic delivery demonstrates a successful proof of principle and holds significant promise as a candidate for HIV-1 prophylaxis in vulnerable populations.

  7. Comparison of SGA oral medications and a long-acting injectable SGA: the PROACTIVE study.

    PubMed

    Buckley, Peter F; Schooler, Nina R; Goff, Donald C; Hsiao, John; Kopelowicz, Alexander; Lauriello, John; Manschreck, Theo; Mendelowitz, Alan J; Miller, Del D; Severe, Joanne B; Wilson, Daniel R; Ames, Donna; Bustillo, Juan; Mintz, Jim; Kane, John M

    2015-03-01

    Until relatively recently, long-acting injectable (LAI) formulations were only available for first-generation antipsychotics and their utilization decreased as use of oral second-generation antipsychotics (SGA) increased. Although registry-based naturalistic studies show LAIs reduce rehospitalization more than oral medications in clinical practice, this is not seen in recent randomized clinical trials. PROACTIVE (Preventing Relapse Oral Antipsychotics Compared to Injectables Evaluating Efficacy) relapse prevention study incorporated efficacy and effectiveness features. At 8 US academic centers, 305 patients with schizophrenia or schizoaffective disorder were randomly assigned to LAI risperidone (LAI-R) or physician's choice oral SGAs. Patients were evaluated during the 30-month study by masked, centralized assessors using 2-way video, and monitored biweekly by on-site clinicians and assessors who knew treatment assignment. Relapse was evaluated by a masked Relapse Monitoring Board. Differences between LAI-R and oral SGA treatment in time to first relapse and hospitalization were not significant. Psychotic symptoms and Brief Psychiatric Rating Scale total score improved more in the LAI-R group. In contrast, the LAI group had higher Scale for Assessment of Negative Symptoms Alogia scale scores. There were no other between-group differences in symptoms or functional improvement. Despite the advantage for psychotic symptoms, LAI-R did not confer an advantage over oral SGAs for relapse or rehospitalization. Biweekly monitoring, not focusing specifically on patients with demonstrated nonadherence to treatment and greater flexibility in changing medication in the oral treatment arm, may contribute to the inability to detect differences between LAI and oral SGA treatment in clinical trials.

  8. Pharmacokinetics of an injectable long-acting formulation of doxycycline hyclate in dogs

    PubMed Central

    2012-01-01

    Based on its PK/PD ratios, doxycycline hyclate (DOX-h), a time-dependant antibacterial, is ideally expected to achieve both sustained plasma drug concentrations at or slightly above the MIC level for as long as possible between dosing intervals. Pursuing this end, a poloxamer-based matrix was used to produce a long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its SC injection to dogs (≤ 0.3 mL per injection site), and results compared with the oral (PO) and IV pharmacokinetics of DOX-h, prepared as tablet or as freshly made solution. A crossover (4 x 4 x 4) study design was employed with 12 Mongrel dogs, with washout periods of 21 days, and at dose of 10 mg/kg in all cases. DOX-h-LA showed the greatest values for bioavailability (199.48%); maximum serum concentration (Cmax) value was 2.8 ± 0.3 with a time to reach Cmax (Tmax) of 2.11 ± 0.12 h and an elimination half-life of 133.61 ± 6.32 h. Considering minimum effective serum concentration of 0.5 μg/mL, a dose-interval of at least 1 week h can be achieved for DOX-h-LA, and only 48 h and 24 h after the IV or PO administration of DOX-h as a solution or as tablets, respectively. A non-painful small bulge, apparently non-inflammatory could be distinguished at injection sites. These lumps dissipated completely in 30 days in all cases. PMID:22682068

  9. Meta-analysis of the efficacy and safety of long-acting non-ergot dopamine agonists in Parkinson's disease.

    PubMed

    Zhou, Chang-Qing; Zhang, Jiang-Wei; Wang, Min; Peng, Guo-Guang

    2014-07-01

    A meta-analysis of randomized controlled trials (RCT) was performed to evaluate the efficacy and safety of long-acting non-ergot dopamine agonists (NEDA) versus placebo in Parkinson's disease (PD). A comprehensive literature search up to February 2013 was performed, and the weighted mean differences (WMD) and relative risks (RR) with 95% confidence intervals (CI) were calculated. Nine RCT (n=2857) which assessed the rotigotine transdermal patch, extended-release pramipexole, and ropinirole prolonged-release, were included. Compared with placebo, long-acting NEDA achieved greater improvements in Unified Parkinson's Disease Rating Scale activities of daily living (ADL) score (WMD -1.77, 95% CI -2.13 to -1.41), motor score (WMD -4.18, 95% CI -4.94 to -3.43) and the ADL and motor subtotal score (WMD -5.12, 95% CI -6.16 to -4.07), as well as a reduction in "off" time (WMD -1.29, 95% CI -1.64 to -0.93) and an increase in "on" time without troublesome dyskinesia (WMD 1.55, 95% CI 1.06 to 2.04). Compared with placebo, long-acting NEDA were associated with a higher risk of nausea, but no difference was found in headache incidence. Higher risks of dizziness, somnolence, constipation, vomiting, and insomnia were only found in early PD while higher risks of dyskinesia and hallucination were only found in advanced PD. The results of our meta-analysis showed that the use of long-acting NEDA can reduce the symptoms of PD patients. However, long-acting NEDA were also associated with a higher incidence of adverse events, especially in early PD patients, compared with placebo.

  10. [Effect of barnidipine hydrochloride on the autonomic nervous system: difference between short- and long-acting components of calcium antagonist].

    PubMed

    Soejima, K; Akaishi, M; Oyamada, K; Mitamura, H; Ogawa, S

    1997-07-01

    Short-acting calcium antagonists have a deleterious effect on the prognosis for patients with myocardial ischemia, possibly caused by overactivation of sympathetic nerves due to vasodilatation, negative inotropism, or coronary steal. However, there is considerable debate about whether long-acting calcium antagonists as well as the short-acting calcium antagonists have the same effect. Barnidipine-HCl is a newly-developed calcium antagonist with 1:2 short- and long-acting particles. This study evaluated the changes of autonomic tone due to barnidipine. Both the short- and long-acting effect of the calcium antagonist was evaluated. Eleven patients with primary hypertension underwent 24-hour ambulatory electrocardiogram and blood pressure monitoring before and after the treatment with barnidipine. Heart rate and blood pressure were compared before and after the medication. Heart rate variability was analyzed with a Marquette 8000/T. High frequency power (HF), as a parameter of vagal tone, and the ratio to low frequency power (LF), as a parameter of sympathetic tone, were obtained. Twenty-four-hour average blood pressure decreased significantly during the day, but nocturnal hypotension was not observed. Heart rate did not increase. HF decreased at the peak of the short- and long-acting components. LF/HF increased at the peak of the short-acting component. Short-acting particles of barnidipine had a deleterious effect on the autonomic tone, that is overactivation of sympathetic tone and suppression of vagal tone. Long-acting particles of barnidipine suppressed the vagal tone. These findings suggest that short-acting calcium antagonists may cause arrhythmia or deterioration of coronary ischemia.

  11. Cellular uptake, antioxidant and antiproliferative activity of entrapped α-tocopherol and γ-tocotrienol in poly (lactic-co-glycolic) acid (PLGA) and chitosan covered PLGA nanoparticles (PLGA-Chi).

    PubMed

    Alqahtani, Saeed; Simon, Lacey; Astete, Carlos E; Alayoubi, Alaadin; Sylvester, Paul W; Nazzal, Sami; Shen, Yixiao; Xu, Zhimin; Kaddoumi, Amal; Sabliov, Cristina M

    2015-05-01

    The aim of this study was to formulate and characterize α-tocopherol (α-T) and tocotrienol-rich fraction (TRF) entrapped in poly (lactide-co-glycolide) (PLGA) and chitosan covered PLGA (PLGA-Chi) based nanoparticles. The resultant nanoparticles were characterized and the effect of nanoparticles entrapment on the cellular uptake, antioxidant, and antiproliferative activity of α-T and TRF were tested. In vitro uptake studies in Caco2 cells showed that PLGA and PLGA-Chi nanoparticles displayed a greater enhancement in the cellular uptake of α-T and TRF when compared with the control without causing toxicity to the cells (p<0.0001). Furthermore, the cellular internalization of both PLGA and PLGA-Chi nanoparticles labeled with FITC was investigated by fluorescence microscopy; both types of nanoparticles were able to get internalized into the cells with reasonable amounts. However, PLGA-Chi nanoparticles showed significantly higher (3.5-fold) cellular uptake compared to PLGA nanoparticles. The antioxidant activity studies demonstrated that entrapment of α-T and TRF in PLGA and PLGA-Chi nanoparticles exhibited greater ability in inhibiting cholesterol oxidation at 48 h compared to the control. In vitro antiproliferative studies confirmed marked cytotoxicity of TRF on MCF-7 and MDA-MB-231 cell lines when delivered by PLGA and PLGA-Chi nanoparticles after 48 h incubation compared to control. In summary, PLGA and PLGA-Chi nanoparticles may be considered as an attractive and promising approach to enhance the bioavailability and activity of poorly water soluble compounds such as α-tocopherol and tocotrienols.

  12. Tetracycline-HCl-loaded poly(DL-lactide-co-glycolide) microspheres prepared by a spray drying technique: influence of gamma-irradiation on radical formation and polymer degradation.

    PubMed

    Bittner, B; Mäder, K; Kroll, C; Borchert, H H; Kissel, T

    1999-05-01

    Tetracycline-HCl (TCH)-loaded microspheres were prepared from poly(lactide-co-glycolide) (PLGA) by spray drying. The drug was incorporated in the polymer matrix either in solid state or as w/o emulsion. The spin probe 4-hydroxy-2,2,6, 6-tetramethyl-piperidine-1-oxyl (TEMPOL) and the spin trap tert-butyl-phenyl-nitrone (PBN) were co-encapsulated into the TCH-loaded and placebo particles. We investigated the effects of gamma-irradiation on the formation of free radicals in polymer and drug and the mechanism of chain scission after sterilization. Gamma-Irradiation was performed at 26.9 and 54.9 kGy using a 60Co source. The microspheres were characterized especially with respect to the formation of radicals and in vitro polymer degradation. Electron paramagnetic resonance (EPR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), high-performance liquid chromatography (HPLC), gas chromatography-mass spectroscopy (GC-MS), and scanning electron microscopy (SEM) were used for characterization of the microspheres. Using EPR spectroscopy, we successfully detected gamma-irradiation induced free radicals within the TCH-loaded microspheres, while unloaded PLGA did not contain radicals under the same conditions. The relatively low glass transition temperature of the poly(dl-lactide-co-glycolide) (37-39 degrees C) seems to favor subsequent reactions of free radicals due to the high mobility of the polymeric chains. Because of the high melting point of TCH (214 degrees C), the radicals can only be stabilized in drug loaded microspheres. In order to determine the mechanism of polymer degradation after exposure to gamma-rays, the spin trap PBN and the spin probe TEMPOL were encapsulated in the microspheres. gamma-Irradiation of microspheres containing PBN resulted in the formation of a lipophilic spin adduct, indicating that a polymeric radical was generated by random chain scission. Polymer degradation by an unzipping mechanism would have

  13. Metal containing polymeric functional microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1979-01-01

    Polymeric functional microspheres containing metal or metal compounds are formed by addition polymerization of a covalently bondable olefinic monomer such as hydroxyethylmethacrylate in the presence of finely divided metal or metal oxide particles, such as iron, gold, platinum or magnetite, which are embedded in the resulting microspheres. The microspheres can be covalently bonded to chemotherapeutic agents, antibodies, or other proteins providing a means for labeling or separating labeled cells. Labeled cells or microspheres can be concentrated at a specific body location such as in the vicinity of a malignant tumor by applying a magnetic field to the location and then introducing the magnetically attractable microspheres or cells into the circulatory system of the subject. Labeled cells can be separated from a cell mixture by applying a predetermined magnetic field to a tube in which the mixture is flowing. After collection of the labeled cells, the magnetic field is discontinued and the labeled sub-cell population recovered.

  14. Synthesis and characterization of magnetite/PLGA/chitosan nanoparticles

    NASA Astrophysics Data System (ADS)

    Ibarra, Jaime; Melendres, Julio; Almada, Mario; Burboa, María G.; Taboada, Pablo; Juárez, Josué; Valdez, Miguel A.

    2015-09-01

    In this work, we report the synthesis and characterization of a new hybrid nanoparticles system performed by magnetite nanoparticles, loaded in a PLGA matrix, and stabilized by different concentrations of chitosan. Magnetite nanoparticles were hydrophobized with oleic acid and entrapped in a PLGA matrix by the emulsion solvent evaporation method, after that, magnetite/PLGA/chitosan nanoparticles were obtained by adding dropwise magnetite/PLGA nanoparticles in chitosan solutions. Magnetite/PLGA nanoparticles produced with different molar ratios did not show significant differences in size and the 3:1 molar ratio showed best spherical shapes as well as uniform particle size. Isothermal titration calorimetry studies demonstrated that the first stage of PLGA-chitosan interaction is mostly regulated by electrostatic forces. Based on a single set of identical sites model, we obtained for the average number of binding sites a value of 3.4, which can be considered as the number of chitosan chains per nanoparticle. This value was confirmed by using a model based on the DLVO theory and fitting zeta potential measurements of magnetite/PLGA/chitosan nanoparticles. From the adjusted parameters, we found that an average number of chitosan molecules of 3.6 per nanoparticle are attached onto the surface of the PLGA matrix. Finally, we evaluated the effect of surface charge of nanoparticles on a membrane model of endothelial cells performed by a mixture of three phospholipids at the air-water interface. Different isotherms and adsorption curves show that cationic surface of charged nanoparticles strongly interact with the phospholipids mixture and these results can be the basis of future experiments to understand the nanoparticles- cell membrane interaction.

  15. Bioequivalence Study of Two Long-Acting Formulations of Oxytetracycline Following Intramuscular Administration in Bovines.

    PubMed

    Mestorino, Nora; Marchetti, María Laura; Lucas, Mariana Florencia; Modamio, Pilar; Zeinsteger, Pedro; Fernández Lastra, Cecilia; Segarra, Ignacio; Mariño, Eduardo Luis

    2016-01-01

    The aim of this study was to evaluate the bioequivalence of two commercial long-acting formulations based on oxytetracycline (OTC) hydrochloride between the reference formulation (Terramycin LA, Pfizer) and a test formulation (Cyamicin LA, Fort Dodge Saude Animal). Both formulations were administered in a single intramuscular route at a dose of 20 mg OTC/kg of body weight in clinically healthy bovines. The study was carried out according to a one-period parallel design. Plasma samples were analyzed by high-pressure liquid chromatography. The limit of quantitation was 0.050 μg/mL with an accuracy of 101.67% with a coefficient of variation of 13.15%. Analysis of variance and 90% confidence interval tests were used to compare the bioavailability parameters (maximum plasma concentration, C max, and the area under the concentration-versus-time curve extrapolated to infinity, AUC0-∞) of both products. In the case of the time to maximum concentration (T max), non-parametric tests based on Wilcoxon's signed rank test were preferred. The comparison of the mean AUC0-∞ values did not reveal any significant differences (311.40 ± 93.05 μg h/mL and 287.71 ± 45.31 μg h/mL, respectively). The results were similar for the T max (3.58 ± 0.90 h versus 3.42 ± 0.51 h). However, when comparing the mean C max some significant differences were found (8.73 ± 3.66 μg/mL and 10.43 ± 3.84 μg/mL, respectively). The 90% confidence intervals for the ratio of AUC0-∞ and T max values for the reference and test product are within the interval 80-125%, but the 90% confidence intervals for the ratio of C max falls outside the proposed interval. It was concluded that C max of test product are not within the 20% of those of the reference, thus suggesting that test OTC is not bioequivalent to the reference formulation.

  16. Guidelines for the use and management of long-acting injectable antipsychotics in serious mental illness

    PubMed Central

    2013-01-01

    Background Long-acting injectable (LAI) formulations are not widely used in routine practice even though they offer advantages in terms of relapse prevention. As part of a process to improve the quality of care, the French Association for Biological Psychiatry and Neuropsychopharmacology (AFPBN) elaborated guidelines for the use and management of antipsychotic depots in clinical practice. Methods Based on a literature review, a written survey was prepared that asked about 539 options in 32 specific clinical situations concerning 3 fields: target-population, prescription and use, and specific populations. We contacted 53 national experts, 42 of whom (79%) completed the survey. The options were scored using a 9-point scale derived from the Rand Corporation and the University of California in the USA. According to the answers, a categorical rank (first-line/preferred choice, second-line/alternate choice, third-line/usually inappropriate) was assigned to each option. The first-line option was defined as a strategy rated as 7–9 (extremely appropriate) by at least 50% of the experts. The following results summarize the key recommendations from the guidelines after data analysis and interpretation of the results of the survey by the scientific committee. Results LAI antipsychotics are indicated in patients with schizophrenia, schizoaffective disorder, delusional disorder and bipolar disorder. LAI second-generation antipsychotics are recommended as maintenance treatment after the first episode of schizophrenia. LAI first-generation antipsychotics are not recommended in the early course of schizophrenia and are not usually appropriate in bipolar disorder. LAI antipsychotics have long been viewed as a treatment that should only be used for a small subgroup of patients with non-compliance, frequent relapses or who pose a risk to others. The panel considers that LAI antipsychotics should be considered and systematically proposed to any patients for whom maintenance

  17. Vouchers in Fragile States: Reducing Barriers to Long-Acting Reversible Contraception in Yemen and Pakistan

    PubMed Central

    Boddam-Whetham, Luke; Gul, Xaher; Al-Kobati, Eman; Gorter, Anna C

    2016-01-01

    ABSTRACT In conflict-affected states, vouchers have reduced barriers to reproductive health services and have enabled health programs to use targeted subsidies to increase uptake of specific health services. Vouchers can also be used to channel funds to public- and private-service providers and improve service quality. The Yamaan Foundation for Health and Social Development in Yemen and the Marie Stopes Society (MSS) in Pakistan—both working with Options Consultancy Services—have developed voucher programs that subsidize voluntary access to long-acting reversible contraceptives (LARCs) and permanent methods (PMs) of family planning in their respective fragile countries. The programs focus on LARCs and PMs because these methods are particularly difficult for poor women to access due to their cost and to provider biases against offering them. Using estimates of expected voluntary uptake of LARCs and PMs for 2014 based on contraceptive prevalence rates, and comparing these with uptake of LARCs and PMs through the voucher programs, we show the substantial increase in service utilization that vouchers can enable by contributing to an expanded method choice. In the governorate of Lahj, Yemen, vouchers for family planning led to an estimated 38% increase in 2014 over the expected use of LARCs and PMs (720 vs. 521 expected). We applied the same approach in 13 districts of Punjab, Khyber Pakhtunkhwa (KPK), and Sindh provinces in Pakistan. Our calculations suggest that vouchers enabled 10 times more women than expected to choose LARCs and PMs in 2014 in those areas of Pakistan (73,639 vs. 6,455 expected). Voucher programs can promote and maintain access to family planning services where existing health systems are hampered. Vouchers are a flexible financing approach that enable expansion of contraceptive choice and the inclusion of the private sector in service delivery to the poor. They can keep financial resources flowing where the public sector is prevented from

  18. Bioequivalence Study of Two Long-Acting Formulations of Oxytetracycline Following Intramuscular Administration in Bovines

    PubMed Central

    Mestorino, Nora; Marchetti, María Laura; Lucas, Mariana Florencia; Modamio, Pilar; Zeinsteger, Pedro; Fernández Lastra, Cecilia; Segarra, Ignacio; Mariño, Eduardo Luis

    2016-01-01

    The aim of this study was to evaluate the bioequivalence of two commercial long-acting formulations based on oxytetracycline (OTC) hydrochloride between the reference formulation (Terramycin LA, Pfizer) and a test formulation (Cyamicin LA, Fort Dodge Saude Animal). Both formulations were administered in a single intramuscular route at a dose of 20 mg OTC/kg of body weight in clinically healthy bovines. The study was carried out according to a one-period parallel design. Plasma samples were analyzed by high-pressure liquid chromatography. The limit of quantitation was 0.050 μg/mL with an accuracy of 101.67% with a coefficient of variation of 13.15%. Analysis of variance and 90% confidence interval tests were used to compare the bioavailability parameters (maximum plasma concentration, Cmax, and the area under the concentration-versus-time curve extrapolated to infinity, AUC0–∞) of both products. In the case of the time to maximum concentration (Tmax), non-parametric tests based on Wilcoxon’s signed rank test were preferred. The comparison of the mean AUC0–∞ values did not reveal any significant differences (311.40 ± 93.05 μg h/mL and 287.71 ± 45.31 μg h/mL, respectively). The results were similar for the Tmax (3.58 ± 0.90 h versus 3.42 ± 0.51 h). However, when comparing the mean Cmax some significant differences were found (8.73 ± 3.66 μg/mL and 10.43 ± 3.84 μg/mL, respectively). The 90% confidence intervals for the ratio of AUC0–∞ and Tmax values for the reference and test product are within the interval 80–125%, but the 90% confidence intervals for the ratio of Cmax falls outside the proposed interval. It was concluded that Cmax of test product are not within the 20% of those of the reference, thus suggesting that test OTC is not bioequivalent to the reference formulation. PMID:27446938

  19. Photonic crystal microspheres

    NASA Astrophysics Data System (ADS)

    Zhokhov, A. A.; Masalov, V. M.; Sukhinina, N. S.; Matveev, D. V.; Dolganov, P. V.; Dolganov, V. K.; Emelchenko, G. A.

    2015-11-01

    Spherical samples of photonic crystals formed by colloidal SiO2 nanoparticles were synthesized. Synthesis of microspheres from 160 nm, 200 nm and 430 nm diameter colloidal nanoparticles was performed over a wide size range, from 5 μm to 50 μm. The mechanism of formation of void microparticles exceeding 50 μm is discussed. The spectral measurements verified the association of the spectra with the peaks of selective reflection from the cubic lattice planes. The microparticle morphology is characterized by scanning electron microscopy (SEM).

  20. Chalcogenide glass microsphere laser.

    PubMed

    Elliott, Gregor R; Murugan, G Senthil; Wilkinson, James S; Zervas, Michalis N; Hewak, Daniel W

    2010-12-06

    Laser action has been demonstrated in chalcogenide glass microsphere. A sub millimeter neodymium-doped gallium lanthanum sulphide glass sphere was pumped at 808 nm with a laser diode and single and multimode laser action demonstrated at wavelengths between 1075 and 1086 nm. The gallium lanthanum sulphide family of glass offer higher thermal stability compared to other chalcogenide glasses, and this, along with an optimized Q-factor for the microcavity allowed laser action to be achieved. When varying the pump power, changes in the output spectrum suggest nonlinear and/or thermal effects have a strong effect on laser action.

  1. Systemic delivery to central nervous system by engineered PLGA nanoparticles

    PubMed Central

    Cai, Qiang; Wang, Long; Deng, Gang; Liu, Junhui; Chen, Qianxue; Chen, Zhibiao

    2016-01-01

    Neurological disorders are an important global public health problem, but pharmaceutical treatments are limited due to drug access to the central nervous system being restricted by the blood-brain barrier (BBB). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are one of the most promising drug and gene delivery systems for crossing the BBB. While these systems offer great promise, PLGA NPs also have some intrinsic drawbacks and require further engineering for clinical and research applications. Multiple strategies have been developed for using PLGA NPs to deliver compounds across the BBB. We classify these strategies into three categories according to the adaptations made to the PLGA NPs (1) to facilitate travel from the injection site (pre-transcytosis strategies); (2) to enhance passage across the brain endothelial cells (BBB transcytosis strategies) and (3) to achieve targeting of the impaired nervous system cells (post-transcytosis strategies). PLGA NPs modified according to these three strategies are denoted first, second, and third generation NPs, respectively. We believe that fusing these three strategies to engineer multifunctional PLGA NPs is the only way to achieve translational applications. PMID:27158367

  2. Stabilization of a model formalinized protein antigen encapsulated in poly(lactide-co-glycolide)-based microspheres.

    PubMed

    Jiang, W; Schwendeman, S P

    2001-10-01

    A formaldehyde-mediated aggregation pathway (FMAP) has been shown to be primarily responsible for the solid-state aggregation of lyophilized formalinized protein antigens [e.g., tetanus toxoid (TT) and formalinized bovine serum albumin (f-BSA)] in the presence of moisture and physiological temperature. Coincorporation of the formaldehyde-interacting amino acid, histidine, strongly inhibits the FMAP. The purpose of this study was to test whether previous solid-state data are applicable toward the stabilization of formalinized antigens encapsulated in poly(lactide-co-glycolide) (PLGA)-based microspheres. Formaldehyde-treated bovine serum albumin (f-BSA) and BSA were selected as a model formalinized protein antigen and a nonformalinized control, respectively. As in the solid state, we found that the FMAP was dominant in the aggregation of f-BSA encapsulated in PLGA 50/50 microspheres, whereas the aggregation mechanism of encapsulated BSA was mostly converted from thiol-disulfide interchange to an acid-catalyzed noncovalent pathway. The lack of noncovalent aggregation in encapsulated f-BSA could be explained by its higher thermodynamic stability after formalinization, which inhibits protein unfolding. Targeting the FMAP, coencapsulation of histidine and trehalose successfully inhibited the aggregation of f-BSA in microspheres. By combining the use of an optimized oil-in-oil (o/o) encapsulation method, coencapsulation of histidine and trehalose, and use of low-acid-content poly(D,L-lactide) (PLA) and poly(ethylene glycol) (PEG) blends, a 2-month continuous release of f-BSA was achieved with the absence of aggregation.

  3. A simple and robust method for pre-wetting poly (lactic-co-glycolic) acid microspheres.

    PubMed

    Wright, Bernice; Parmar, Nina; Bozec, Laurent; Aguayo, Sebastian D; Day, Richard M

    2015-08-01

    Poly (lactic-co-glycolic) acid microspheres are amenable to a number of biomedical procedures that support delivery of cells, drugs, peptides or genes. Hydrophilisation or wetting of poly (lactic-co-glycolic) acid are an important pre-requisites for attachment of cells and can be achieved via exposure to plasma oxygen or nitrogen, surface hydrolysis with NaOH or chloric acid, immersion in ethanol and water, or prolonged incubation in phosphate buffered saline or cell culture medium. The aim of this study is to develop a simple method for wetting poly (lactic-co-glycolic) acid microspheres for cell delivery applications. A one-step ethanol immersion process that involved addition of serum-supplemented medium and ethanol to PLGA microspheres over 30 min-24 h is described in the present study. This protocol presents a more efficient methodology than conventional two-step wetting procedures. Attachment of human skeletal myoblasts to poly (lactic-co-glycolic) acid microspheres was dependent on extent of wetting, changes in surface topography mediated by ethanol pre-wetting and serum protein adsorption. Ethanol, at 70% (v/v) and 100%, facilitated similar levels of wetting. Wetting with 35% (v/v) ethanol was only achieved after 24 h. Pre-wetting (over 3 h) with 70% (v/v) ethanol allowed significantly greater (p ≤ 0.01) serum protein adsorption to microspheres than wetting with 35% (v/v) ethanol. On serum protein-loaded microspheres, greater numbers of myoblasts attached to constructs wetted with 70% ethanol than those partially wetted with 35% (v/v) ethanol. Microspheres treated with 70% (v/v) ethanol presented a more rugose surface than those treated with 35% (v/v) ethanol, indicating that more efficient myoblast adhesion to the former may be at least partially attributed to differences in surface structure. We conclude that our novel protocol for pre-wetting poly (lactic-co-glycolic) acid microspheres that incorporates biochemical and structural features

  4. Microsphere based saliva diagnostics

    NASA Astrophysics Data System (ADS)

    Rissin, David M.; DiCesare, Christopher; Hayman, Ryan B.; Blicharz, Timothy M.; Walt, David R.

    2005-11-01

    Saliva presents a minimally invasive alternative medium to blood for performing diagnostics1. Microsphere sensors for ions, small organic molecules, and proteins are currently being developed and optical microarrays containing thousands of these sensors will be used for simultaneous multi-analyte analysis. The fiber bundle platform in use is 1mm in diameter and contains approximately 50,000 individually addressable 3.1μm fibers, each with an etched well capable of housing a single 3.1μm microsphere sensor. Micron-sized bead-based chemistries are produced in house, followed by deposition onto a fiber-optic bundle platform, allowing for multiplexed analysis. The ultimate goal is to develop a universal diagnostic system using saliva as the diagnostic medium. This platform will permit multiplexed analysis of a sample by integrating microfluidics with the optical arrays loaded with sensors capable of detecting relevant biomarkers associated with a wide range of disease states. Disease states that are currently under investigation include end stage renal disease (ESRD) and Sjoegrens Syndrome (SS).

  5. Towards Monodispersed Polymer Microspheres

    NASA Astrophysics Data System (ADS)

    Senuma, Yoshinori; Hilborn, Jons

    1998-03-01

    Uniform polymer microspheres prepared by Spinning Disk Atomization Our spinning disk atomization (SDA) can, relative to other existing techniques, produce micron-sized particles of very narrow size distribution. Around the edge of the disk, small teeth channel the flow into identical droplets that are flung off over the disk rim. These solidify during flight to form spherical particles. Applications for spheres produced by SDA can be found in areas such as adhesives, powder coatings, food, biomedical use, drug delivery systems, etc. We have atomized polyethyleneglycol into very narrowly dispersed microspheres ranging from 50 to 500 =B5m. The aim of this work is to model the droplet formation occurring at the rim of the spinning disk in order to better understand the experimental results. The viscosity contribution in the fluid breakup is qualitatively analyzed and is adapted to the theoretical model to show how it affects the droplet size. We have used the pendant drop model (Ramesh Babu, S. Journal of Colloid and Interface Science 116, 350-372 (1987).) for spinning disk atomization to describe the drop-shape evolution during growth.

  6. Multispecies resistance of cattle gastrointestinal nematodes to long-acting avermectin formulations in Mato Grosso do Sul.

    PubMed

    Borges, Fernando de Almeida; Borges, Dyego Gonçalves Lino; Heckler, Rafael Pereira; Neves, Juliana Paniago Lordello; Lopes, Fernando Gonçalves; Onizuka, Marcel Kenzo Vilalba

    2015-09-15

    The use of long-acting avermectins (AVMs) in cattle to treat infections with gastrointestinal nematodes was common in Brazil until its prohibition by state authorities. The prohibition; however, was rescinded in 2015, but a scientific discussion of the pros and cons of the use of these formulations is necessary. We evaluated the levels of resistance to 1.0 and 3.5% doramectin and to 3.15% ivermectin in cattle. The worms in animals treated with 3.5% doramectin were characterized by the suppression of oviposition and by a higher proportion of adult females carrying no eggs. Haemonchus placei, Cooperia punctata, C. pectinata, C. spatulata, and Oesophagostomum radiatum were resistant to the above compositions. The administration of long-acting AVM formulations did not result in a higher efficacy against these helminth populations.

  7. Chemical Conjugation of Evans Blue Derivative: A Strategy to Develop Long-Acting Therapeutics through Albumin Binding

    PubMed Central

    Chen, Haojun; Wang, Guohao; Lang, Lixin; Jacobson, Orit; Kiesewetter, Dale O.; Liu, Yi; Ma, Ying; Zhang, Xianzhong; Wu, Hua; Zhu, Lei; Niu, Gang; Chen, Xiaoyuan

    2016-01-01

    The efficacy of therapeutic drugs is highly dependent on their optimal in vivo pharmacokinetics. Albumin conjugation is considered to be one of the most effective means of protracting the short lifespan of peptides and proteins. In this study, we proposed a novel platform for developing long lasting therapeutics by conjugating a small molecular albumin binding moiety, truncated Evans blue, to either peptides or proteins. Using the anti-diabetic peptide drug Exendin-4 as a model peptide, we synthesized a new long-acting Exendin-4 derivative (denoted as Abextide). Through complexation with albumin in situ, the biological half-life of Abextide was significantly extended. The hypoglycemic effect of Abextide was also improved remarkably over Exendin-4. Thus, Abextide has considerable potential to treat type 2 diabetes. This strategy as a general technology platform can be applied to other small molecules and biologics for the development of long-acting therapeutic drugs. PMID:26877782

  8. Risperidone long-acting injectable (Risperdal Consta®) for maintenance treatment in patients with bipolar disorder.

    PubMed

    Bobo, William V; Shelton, Richard C

    2010-11-01

    Poor adherence to pharmacotherapy during maintenance-phase treatment of bipolar disorder is a common occurrence, exposing patients to a high risk of illness relapses, rehospitalization and other negative outcomes. In view of this, there has been a reawakening of interest in the potential of long-acting injectable antipsychotic medications to improve treatment outcome during bipolar maintenance therapy. Indeed, long-acting injectable medications have practical advantages of assuring delivery of medication at a prescribed dose, and perhaps also making it easier to monitor adherence, at least to the long-acting drug. However, there are important limitations to the long-term use of depot typical neuroleptics in patients with bipolar disorder, including risk of extrapyramidal side effects and tardive dyskinesia, which may exceed that of patients with schizophrenia, and the potential for treatment-emergent exacerbation of depressive symptoms. Long-acting injectable risperidone (RLAI) has recently been approved for maintenance treatment in patients with bipolar I disorder. Evidence supporting the use of RLAI for this indication consists of several nonrandomized, open-label studies; one randomized, open-label trial; and two adequately powered randomized, double-blind trials. In general, these studies have shown RLAI to be effective for the prevention of relapse or hospitalization during bipolar maintenance treatment. In the double-blind studies, RLAI was associated with reduced relapse rates, increased time to relapse and greater control of clinical symptoms during maintenance treatment following initial stabilization, compared with oral medication treatment or placebo injection. RLAI appeared to be more effective for preventing manic/mixed episodes than depressive episodes. RLAI showed good tolerability across studies; however, dose-related extrapyramidal effects, sedation, weight gain and prolactin elevation may occur during long-term treatment. Responder

  9. Long-acting calcium channel antagonist pranidipine prevents ventricular remodeling after myocardial infarction in rats.

    PubMed

    Takeuchi, K; Omura, T; Yoshiyama, M; Yoshida, K; Otsuka, R; Shimada, Y; Ujino, K; Yoshikawa, J

    1999-01-01

    The purpose of this study was to examine the effects of the long-acting calcium channel antagonist pranidipine on ventricular remodeling, systolic and diastolic cardiac function, circulating humoral factors, and cardiac mRNA expression in myocardial infarcted rats. Myocardial infarction (MI) was produced by ligation of the coronary artery in Wistar rats. Three mg/kg per day of pranidipine was randomly administered to the infarcted rats. Hemodynamic measurements, Doppler echocardiographic examinations, analyses of the plasma levels of humoral factors, and myocardial mRNA expression were performed at 4 weeks after myocardial infarction. Left ventricular end-diastolic pressure (LVEDP) and central venous pressure (CVP) increased to 24.2 +/- 1.2mmHg and 5.4 +/- 0.6 mmHg. Pranidipine reduced LVEDP and CVP to 13.6 +/- 1.4mmHg (P < 0.01) and 2.5 +/- 0.4mmHg (P < 0.01). The weight of the left and right ventricles in MI was significantly higher than in the sham-operated rats (sham, 2.02 +/- 0.04 and 0.47 +/- 0.02g/kg; MI, 2.18 +/- 0.05 and 0.79 +/- 0.04g/ kg; P < 0.01). Left ventricular end-diastolic dimension (LVDd) in MI increased to 10.3 +/- 0.3mm (P < 0.01) (sham, 6.4 +/- 0.3mm). Pranidipine prevented an increase in the weight of the left and right ventricles (2.02 +/- 0.04 and 0.6 +/- 0.03g/kg, P < 0.01) and LVDd (7.9 +/-0.2mm, P < 0.01 to MI). Plasma renin activity (PRA), and plasma epinephrine, norepinephrine, and dopamine concentrations in MI were higher than those of the sham-operated rats. Pranidipine decreased the PRA and plasma cathecolamine levels of the myocardial infarcted rats to the level of the sham-operated rats. Moreover, the rats in MI showed systolic dysfunction, shown by decreased fractional shortening (sham, 31 +/- 2% vs MI, 15 +/- 1%; P < 0.01) and diastolic dysfunction shown by the E-wave deceleration rate (sham, 12.8 +/- 1.1 m/s2; MI, 32.6 +/- 2.1 m/s2; P < 0.01). Pranidipine significantly prevented systolic and diastolic dysfunction. The increases

  10. Knowledge and perception on long acting and permanent contraceptive methods in adigrat town, tigray, northern ethiopia: a qualitative study.

    PubMed

    Gebremariam, Alem; Addissie, Adamu

    2014-01-01

    Background. Long acting and permanent contraceptive methods have the potential to reduce unintended pregnancies but the contraceptive choice and utilization in Ethiopia are highly dominated by short term contraceptives. Objective. To assess the knowledge and perception on long acting and permanent contraceptives of married women and men in Northern Ethiopia. Method. A qualitative method was conducted in Adigrat on January, 2012. Four focus group discussions with married women and men and six in-depth interviews with family planning providers were conducted. Content analysis was used to synthesize the data. Result. Participants' knowledge on long acting and permanent contraceptives is limited to recognizing the name of the methods. Most of the participants are not able to identify permanent methods as a method of contraception. They lack basic information on how these methods work and how they can use it. Women had fears and rumors about each of these methods. They prefer methods which do not require any procedure. Family planning providers stated as they have weakness on counseling of all contraceptive choices. Conclusion. There are personal barriers and knowledge gaps on these contraceptive methods. Improving the counseling service program can help women to increase knowledge and avoid misconceptions of each contraceptive choice.

  11. Creation of a Long-Acting Nanoformulated 2′,3′-Dideoxy-3′-Thiacytidine

    PubMed Central

    Guo, Dongwei; Zhou, Tian; Araínga, Mariluz; Palandri, Diana; Gautam, Nagsen; Bronich, Tatiana; Alnouti, Yazen; McMillan, JoEllyn; Edagwa, Benson

    2017-01-01

    Background: Antiretroviral drug discovery and formulation design will facilitate viral clearance in infectious reservoirs. Although progress has been realized for selected hydrophobic integrase and nonnucleoside reverse transcriptase inhibitors, limited success has been seen to date with hydrophilic nucleosides. To overcome these limitations, hydrophobic long-acting drug nanoparticles were created for the commonly used nucleoside reverse transcriptase inhibitor, lamivudine (2′,3′-dideoxy-3′-thiacytidine, 3TC). Methods: A 2-step synthesis created a slow-release long-acting hydrophobic 3TC. Conjugation of 3TC to a fatty acid created a myristoylated prodrug which was encased into a folate-decorated poloxamer 407. Both in vitro antiretroviral efficacy in human monocyte-derived macrophages and pharmacokinetic profiles in mice were evaluated for the decorated nanoformulated drug. Results: A stable drug formulation was produced by poloxamer encasement that improved monocyte–macrophage uptake, antiretroviral activities, and drug pharmacokinetic profiles over native drug formulations. Conclusions: Sustained release of long-acting antiretroviral therapy is a new therapeutic frontier for HIV/AIDS. 3TC depot formation in monocyte-derived macrophages can be facilitated through stable subcellular internalization and slow drug release. PMID:27559685

  12. Microsphere delivery of Risperidone as an alternative to combination therapy.

    PubMed

    D'Souza, Susan; Faraj, Jabar; DeLuca, Patrick

    2013-11-01

    The purpose of this study was to develop a parenteral delivery system of Risperidone that would provide initial and extended drug release and thereby avoid the need for co-administration of oral tablets. Key formulation parameters utilized to achieve desired therapeutic levels in vivo were particle size and drug loading. Three poly (D,L-lactide-co-glycolide) (PLGA) microsphere formulations (Formulations A, B, and C) that encapsulated Risperidone were prepared by varying particle size (19-49 μm) and drug loading parameters (31-37%) but with a uniform bulk density (0.66-0.69)g/cc and internal porosity, utilizing the solvent extraction/evaporation method. The microspheres were characterized for drug content by HPLC, particle size by laser diffractometry, surface morphology by scanning electron microscopy (SEM), and in vivo drug release. In vivo studies were performed in male Sprague-Dawley rats, and levels of the active moiety (Risperidone and its metabolite, 9-hydroxyrisperidone) were assessed. In vivo release profiles from the three microsphere formulations were dependent on particle size and drug loading. The smaller sized microspheres (Formulation A) exhibited a large initial burst and a shorter duration of action, while the larger particles exhibited a smaller initial burst (Formulations B and C) but released drug for a much longer period in vivo. Extended duration of drug release was ascribed to higher drug content in the microspheres. A biweekly simulation of multiple dosing revealed that Formulation C, the selected formulation, with a high load and large particle size would provide adequate initial and maintenance levels of the active moiety (Risperidone and its metabolite, 9-hydroxyrisperidone). A comparison of biweekly dosing in vivo of Formulation C with the marketed product showed that at steady state, though average concentrations for both preparations were similar, the time taken to achieve steady state was much faster for Formulation C. The delay in

  13. The effect of formulation variables on the characteristics of insulin-loaded poly(lactic-co-glycolic acid) microspheres prepared by a single phase oil in oil solvent evaporation method.

    PubMed

    Hamishehkar, Hamed; Emami, Jaber; Najafabadi, Abdolhossein Rouholamini; Gilani, Kambiz; Minaiyan, Mohsen; Mahdavi, Hamid; Nokhodchi, Ali

    2009-11-01

    Biodegradable polymeric microspheres are ideal vehicles for controlled delivery applications of drugs, peptides and proteins. Amongst them, poly(lactic-co-glycolic acid) (PLGA) has generated enormous interest due to their favorable properties and also has been approved by FDA for drug delivery. Insulin-loaded PLGA microparticles were prepared by our developed single phase oil in oil (o/o) emulsion solvent evaporation technique. Insulin, a model protein, was successfully loaded into microparticles by changing experimental variables such as polymer molecular weight, polymer concentration, surfactant concentration and stirring speed in order to optimize process variables on drug encapsulation efficiency, release rates, size and size distribution. A 2(4) full factorial design was employed to evaluate systematically the combined effect of variables on responses. Scanning electron microscope (SEM) confirmed spherical shapes, smooth surface morphology and microsphere structure without aggregation. FTIR and DSC results showed drug-polymer interaction. The encapsulation efficiency of insulin was mainly influenced by surfactant concentration. Moreover, polymer concentration and polymer molecular weight affected burst release of drug and size characteristics of microspheres, respectively. It was concluded that using PLGA with higher molecular weight, high surfactant and polymer concentrations led to a more appropriate encapsulation efficiency of insulin with low burst effect and desirable release pattern.

  14. Short- and long-term peripheral nerve regeneration using a poly-lactic-co-glycolic-acid scaffold containing nerve growth factor and glial cell line-derived neurotrophic factor releasing microspheres.

    PubMed

    de Boer, Ralph; Borntraeger, Andreas; Knight, Andrew M; Hébert-Blouin, Marie-Noëlle; Spinner, Robert J; Malessy, Martijn J A; Yaszemski, Michael J; Windebank, Anthony J

    2012-08-01

    Addition of neural growth factors to bioengineered scaffolds may improve peripheral nerve regeneration. The aim of this study is to evaluate the short- and long term effect of microsphere delivered nerve growth factor (NGF) and glial cell derived neurotrophic factor (GDNF) in the 10 mm rat sciatic nerve gap. Eighty-four rats were assigned to seven groups (n = 6) at two endpoints (6 and 16 weeks): saline, saline NGF, saline NGF-microspheres, saline GDNF, saline GDNF-microspheres, saline blank microspheres, and autologous nerve graft. Total fascicular area and total number of myelinated fibers at mid-tube increased in all conduit groups between 6 and 16 weeks. Autologous, saline NGF-microsphere and saline GDNF-microsphere groups reached maximal histomorphometric values by 6 weeks (p < 0.05). Compound muscle action potentials returned after 6 weeks for the autologous graft and continued to increase to a level of 3.6 ± 1.9 mV at endpoint. No significant differences were found between study groups as measured by ankle angle. These experiments show an initial beneficial effect of incorporation of NGF- or GDNF-microspheres in a PLGA 85/15 nerve conduit, since histomorphometric values reached their maximum by 6 weeks compared to control groups. These results do not yet extrapolate into improved electrophysiological or functional improvement.

  15. Janus nanogels of PEGylated Taxol and PLGA-PEG-PLGA copolymer for cancer therapy

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Wang, Huaimin; Zhu, Meifeng; Ding, Dan; Li, Dongxia; Yin, Zhinan; Wang, Lianyong; Yang, Zhimou

    2013-09-01

    Nanogels are promising carriers for the delivery of anti-cancer drugs for cancer therapy. We report in this study on a Janus nanogel system formed by mixing a prodrug of Taxol (PEGylated Taxol) and a copolymer of PLGA-PEG-PLGA. The Janus nanogels have good stability over months in aqueous solutions and the freeze-dried powder of nanogels can be re-dispersed instantly in aqueous solutions. The Janus nanogels show an enhanced inhibition effect on tumor growth in a mice breast cancer model probably due to the enhanced uptake of the nano-sized materials by the EPR effect. What is more, the nanogels can also serve as physical carriers to co-deliver other anti-cancer drugs such as doxorubicin to further improve the anti-cancer efficacy. The results obtained from H&E staining and TUNEL assay also support the observation of tumor growth inhibition. These results suggest the potential of this novel delivery system for cancer therapy.Nanogels are promising carriers for the delivery of anti-cancer drugs for cancer therapy. We report in this study on a Janus nanogel system formed by mixing a prodrug of Taxol (PEGylated Taxol) and a copolymer of PLGA-PEG-PLGA. The Janus nanogels have good stability over months in aqueous solutions and the freeze-dried powder of nanogels can be re-dispersed instantly in aqueous solutions. The Janus nanogels show an enhanced inhibition effect on tumor growth in a mice breast cancer model probably due to the enhanced uptake of the nano-sized materials by the EPR effect. What is more, the nanogels can also serve as physical carriers to co-deliver other anti-cancer drugs such as doxorubicin to further improve the anti-cancer efficacy. The results obtained from H&E staining and TUNEL assay also support the observation of tumor growth inhibition. These results suggest the potential of this novel delivery system for cancer therapy. Electronic supplementary information (ESI) available: Synthesis and characterization of compounds, dynamic time sweep, H

  16. Use and Outcomes Associated with Long-acting Bronchodilators among Patients Hospitalized for Chronic Obstructive Pulmonary Disease

    PubMed Central

    Shieh, Meng-Shiou; Pekow, Penelope S.; Stefan, Mihaela S.

    2014-01-01

    Rationale: Long-acting β-adrenergic agonists and long-acting anticholinergic agents are recommended for the management of patients with stable chronic obstructive pulmonary disease (COPD); however, their role in the acute setting is uncertain. Objectives: To describe the use and outcomes associated with long-acting bronchodilator therapy (LABD) among patients hospitalized with exacerbations of COPD. Methods: We conducted a retrospective cohort study at 421 U.S. hospitals of patients hospitalized with exacerbations of COPD between January 1, 2010, and June 30, 2011. We used propensity score methods to compare the risk of a composite measure of treatment failure, length of stay, and hospital costs in patients who were treated with an LABD to those who did not receive treatment. Measurements and Main Results: Of the 77,378 patients included in the analysis, 31,725 (41%) were treated with an LABD on Hospital Day 1 or Day 2, including 15,356 (48.4%) who received a long-acting β-agonist, 6,665 (21%) who received a long-acting anticholinergic, and 9,704 (30.6%) who received both. When compared with patients who were not treated with an LABD, treated patients tended to be younger and had a modestly lower comorbidity burden but were more likely to have had prior admission for COPD and to be treated with inhaled corticosteroids. The incidence of treatment failure was similar among those who were or were not treated with LABDs (13.1 vs. 13.6%, P = 0.06). In propensity-matched analyses we found no difference in the risk of treatment failure associated with exposure to LABDs (relative risk [RR], 1.00; 95% confidence interval [CI], 0.96–1.04), minimal differences in hospital cost (RR, 1.02; 95% CI, 1.01–1.03), and no difference in length of stay (RR, 1.01; 95% CI, 1.00–1.02). Conclusions: Despite a lack of evidence, LABDs are commonly prescribed to patients hospitalized for exacerbations of COPD but are not associated with better clinical or economic outcomes. Clinical

  17. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  18. Material characterization of microsphere-based scaffolds with encapsulated raw materials.

    PubMed

    Sridharan, BanuPriya; Mohan, Neethu; Berkland, Cory J; Detamore, Michael S

    2016-06-01

    "Raw materials," or materials capable of serving both as building blocks and as signals, which are often but not always natural materials, are taking center stage in biomaterials for contemporary regenerative medicine. In osteochondral tissue engineering, a field leveraging the underlying bone to facilitate cartilage regeneration, common raw materials include chondroitin sulfate (CS) for cartilage and β-tricalcium phosphate (TCP) for bone. Building on our previous work with gradient scaffolds based on microspheres, here we delved deeper into the characterization of individual components. In the current study, the release of CS and TCP from poly(D, L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds was evaluated over a time period of 4 weeks. Raw material encapsulated groups were compared to 'blank' groups and evaluated for surface topology, molecular weight, and mechanical performance as a function of time. The CS group may have led to increased surface porosity, and the addition of CS improved the mechanical performance of the scaffold. The finding that CS was completely released into the surrounding media by 4 weeks has a significant impact on future in vivo studies, given rapid bioavailability. The addition of TCP seemed to contribute to the rough external appearance of the scaffold. The current study provides an introduction to degradation patterns of homogenous raw material encapsulated scaffolds, providing characterization data to advance the field of microsphere-based scaffolds in tissue engineering.

  19. Controlled Release of Dutasteride from Biodegradable Microspheres: In Vitro and In Vivo Studies

    PubMed Central

    Xie, Xiangyang; Yang, Yanfang; Chi, Qiang; Li, ZhiPing; Zhang, Hui; Li, Ying; Yang, Yang

    2014-01-01

    The aim of the present work was to study the in vitro/in vivo characteristics of dutasteride loaded biodegradable microspheres designed for sustained release of dutasteride over four weeks. An O/W emulsion-solvent evaporation method was used to incorporate dutasteride, which is of interest in the treatment of benign prostatic hyperplasia (BPH), into poly(lactide-co-glycolide) (PLGA). A response surface method (RSM) with central composite design (CCD) was employed to optimize the formulation variables. A prolonged in vitro drug release profile was observed, with a complete release of the entrapped drug within 28 days. The pharmacokinetics study showed sustained plasma drug concentration-time profile of dutasteride loaded microspheres after subcutaneous injection into rats. The in vitro drug release in rats correlated well with the in vivo pharmacokinetics profile. The pharmacodynamics evaluated by determination of the BPH inhibition in the rat models also showed a prolonged pharmacological response. These results suggest the potential use of dutasteride loaded biodegradable microspheres for the management of BPH over long periods. PMID:25541985

  20. Controlled release of dutasteride from biodegradable microspheres: in vitro and in vivo studies.

    PubMed

    Xie, Xiangyang; Yang, Yanfang; Chi, Qiang; Li, ZhiPing; Zhang, Hui; Li, Ying; Yang, Yang

    2014-01-01

    The aim of the present work was to study the in vitro/in vivo characteristics of dutasteride loaded biodegradable microspheres designed for sustained release of dutasteride over four weeks. An O/W emulsion-solvent evaporation method was used to incorporate dutasteride, which is of interest in the treatment of benign prostatic hyperplasia (BPH), into poly(lactide-co-glycolide) (PLGA). A response surface method (RSM) with central composite design (CCD) was employed to optimize the formulation variables. A prolonged in vitro drug release profile was observed, with a complete release of the entrapped drug within 28 days. The pharmacokinetics study showed sustained plasma drug concentration-time profile of dutasteride loaded microspheres after subcutaneous injection into rats. The in vitro drug release in rats correlated well with the in vivo pharmacokinetics profile. The pharmacodynamics evaluated by determination of the BPH inhibition in the rat models also showed a prolonged pharmacological response. These results suggest the potential use of dutasteride loaded biodegradable microspheres for the management of BPH over long periods.

  1. Mesenchymal stem cells attenuated PLGA-induced inflammatory responses by inhibiting host DC maturation and function.

    PubMed

    Zhu, Heng; Yang, Fei; Tang, Bo; Li, Xi-Mei; Chu, Ya-Nan; Liu, Yuan-Lin; Wang, Shen-Guo; Wu, De-Cheng; Zhang, Yi

    2015-01-01

    The poly lactic-co-glycolic acid (PLGA) bio-scaffold is a biodegradable scaffold commonly used for tissue repair. However, implanted PLGA scaffolds usually cause serious inflammatory responses around grafts. To improve PLGA scaffold-based tissue repair, it is important to control the PLGA-mediated inflammatory responses. Recent evidence indicated that PLGA induce dendritic cell (DC) maturation in vitro, which may initiate host immune responses. In the present study, we explored the modulatory effects of mesenchymal stem cells (MSC) on PLGA-induced DCs (PLGA-DC). We found that mouse MSCs inhibited PLGA-DC dendrite formation, as well as co-stimulatory molecule and pro-inflammatory factor expression. Functionally, MSC-educated PLGA-DCs promoted Th2 and regulatory T cell differentiation but suppressed Th1 and Th17 cell differentiation. Mechanistically, we determined that PLGA elicited DC maturation via inducing phosphorylation of p38/MAPK and ERK/MAPK pathway proteins in DCs. Moreover, MSCs suppressed PLGA-DCs by partially inactivating those pathways. Most importantly, we found that the MSCs were capable of suppressing DC maturation and immune function in vivo. Also, the proportion of mature DCs in the mice that received MSC-PLGA constructs greatly decreased compared with that of their PLGA-film implantation counterparts. Additionally, MSCs co-delivery increased regulatory T and Th2 cells but decreased the Th1 and Th17 cell numbers in the host spleens. Histological analysis showed that MSCs alleviated the inflammatory responses around the grafted PLGA scaffolds. In summary, our findings reveal a novel function for MSCs in suppressing PLGA-induced host inflammatory response and suggest that DCs are a new cellular target in improving PLGA scaffold-based tissue repair.

  2. HDL-mimetic PLGA nanoparticle to target atherosclerosis plaque macrophages.

    PubMed

    Sanchez-Gaytan, Brenda L; Fay, Francois; Lobatto, Mark E; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E M; van Rijs, Sarian M; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J; Langer, Robert; Fayad, Zahi A; Mulder, Willem J M

    2015-03-18

    High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA-HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA-HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers.

  3. In vivo biocompatibility of the PLGA microparticles in parotid gland

    PubMed Central

    Cantín, Mario; Miranda, Patricio; Suazo Galdames, Iván; Zavando, Daniela; Arenas, Patricia; Velásquez, Luis; Vilos, Cristian

    2013-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microparticles are used in various disorders for the controlled or sustained release of drugs, with the management of salivary gland pathologies possible using this technology. There is no record of the response to such microparticles in the glandular parenchyma. The purpose of this study was to assess the morphological changes in the parotid gland when injected with a single dose of PLGA microparticles. We used 12 adult female Sprague Dawley rats (Rattus norvegicus) that were injected into their right parotid gland with sterile vehicle solution (G1, n=4), 0.5 mg PLGA microparticles (G2, n=4), and 0.75 mg PLGA microparticles (G3, n=4); the microparticles were dissolved in a sterile vehicle solution. The intercalar and striated ducts lumen, the thickness of the acini and the histology aspect in terms of the parenchyma organization, cell morphology of acini and duct system, the presence of polymeric residues, and inflammatory response were determined at 14 days post-injection. The administration of the compound in a single dose modified some of the morphometric parameters of parenchyma (intercalar duct lumen and thickness of the glandular acini) but did not induce tissue inflammatory response, despite the visible presence of polymer waste. This suggests that PLGA microparticles are biocompatible with the parotid tissue, making it possible to use intraglandular controlled drug administration. PMID:24228103

  4. Effectiveness of long-acting antipsychotics in clinical practice : 1. A retrospective, 18-month follow up and comparison between paliperidone palmitate, risperidone long-acting injection and zuclopenthixol decanoate

    PubMed Central

    Cordiner, Matthew; Shajahan, Polash; McAvoy, Sarah; Bashir, Muhammad; Taylor, Mark

    2016-01-01

    Objectives: In the UK, nine different compounds are available as long-acting antipsychotic injections (LAIs). There are few clinical guidelines for determining which LAIs are most effective in specific patient groups. To measure the clinical effectiveness of LAIs we aimed to determine the now-established concept of antipsychotic discontinuation rates and measure Clinical Global Impression (CGI) outcomes. Method: The population (n was approximately 560,000) was a secondary care NHS adult mental health service in Lanarkshire, Scotland, UK. This was a retrospective, electronic case note search of LAI-naïve patients commenced on paliperidone palmitate (n = 31), risperidone long-acting injection (RLAI) (n = 102) or zuclopenthixol decanoate (n = 105), with an 18-month follow up. Kaplan–Meier survival statistics for discontinuation rates and hospital admission were calculated. CGI severity and improvement scores were retrospectively assigned by the investigating team. Results: Paliperidone palmitate performed less favourably than risperidone long-acting injection (RLAI) or zuclopenthixol decanoate. Paliperidone palmitate had higher discontinuation rates due to any cause, inefficacy and increased hospitalization risk. Paliperidone palmitate had the smallest proportion of patients assigned a clinically desirable CGI-I score of 1 (very much improved) or 2 (much improved). Conclusions: Paliperidone palmitate had less favourable discontinuation and CGI outcomes compared with RLAI and zuclopenthixol decanoate. This could not be adequately explained by patients in the paliperidone group being more chronically or severely unwell, nor by the presence of comorbidities such as alcohol or substance misuse, or by the use of lower mean dosages compared with RLAI or zuclopenthixol decanoate. We considered that prescribers are familiarizing themselves with paliperidone and outcomes may improve over time. PMID:26913175

  5. Controlled release of simvastatin-loaded thermo-sensitive PLGA-PEG-PLGA hydrogel for bone tissue regeneration: in vitro and in vivo characteristics.

    PubMed

    Yan, Qi; Xiao, Li-Qun; Tan, Lei; Sun, Wei; Wu, Tao; Chen, Liang-Wen; Mei, Yan; Shi, Bin

    2015-11-01

    Reports on the local delivery of drug loaded injectable hydrogels for bone regeneration are currently limited. This study assessed the effect of controlled simvastatin (SIM) release from a thermo-sensitive hydrogel in vitro and in vivo. We successfully manufactured and evaluated thermo-sensitive poly(d,l-lactide-co-glycolide)-poly(ethylene glycol)-poly(d,l-lactide-co-glycolide) triblock copolymers (PLGA-PEG-PLGA) loaded with SIM. The osteogenic effect of this hydrogel was tested in vitro and in vivo. MC-3T3 E1 cells proliferation and osteoblastic differentiation was analyzed after cultivation with the hydrogel extracts. Cells co-cultured with SIM/PLGA-PEG-PLGA extracts showed an increase in mineralization and osteogenic gene expression compared to the other two groups. Additionally, the characteristics of this composite in vivo were demonstrated using a rat bone defect model. The bone defects injected with SIM/PLGA-PEG-PLGA hydrogel showed increased new bone formation compared to samples treated with PLGA-PEG-PLGA and control samples. The results of this study suggest that SIM/PLGA-PEG-PLGA might provide potential therapeutic value for bone healing.

  6. Prevalence and factors affecting use of long acting and permanent contraceptive methods in Jinka town, Southern Ethiopia: a cross sectional study

    PubMed Central

    Mekonnen, Getachew; Enquselassie, Fikre; Tesfaye, Gezahegn; Semahegn, Agumasie

    2014-01-01

    Introduction In Ethiopia, knowledge of contraceptive methods is high though there is low contraceptive prevalence rate. This study was aimed to assess prevalence and associated factors of long acting and permanent contraceptive methods in Jinka town, southern Ethiopia. Methods Community based cross sectional survey was conducted to assess the prevalence and factors affecting long acting and permanent methods of contraceptives utilization from March to April 2008. Eight hundred child bearing age women were participated in the quantitative study and 32 purposively selected focus group discussants were participated in the qualitative study. Face to face interview was used for data collection. Data were analyzed by SPSS version 13.0 statistical software. Descriptive statistics and logistic regression were computed to analyze the data. Results The prevalence of long acting and permanent contraceptive method was 7.3%. Three fourth (76.1%) of the women have ever heard about implants and implant 28 (50%) were the most widely used method. Almost two third of women had intention to use long acting and permanent methods. Knowledge of contraceptive and age of women have significant association with the use of long acting and permanent contraceptive methods. Conclusion The overall prevalence of long acting and permanent contraceptive method was low. Knowledge of contraceptive and age of women have significant association with use of long acting and permanent contraceptive. Extensive health information should be provided. PMID:25404960

  7. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, W.E.

    1982-09-30

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  8. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, William E.

    1984-01-01

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  9. Fabrication of pillared PLGA microvessel scaffold using femtosecond laser ablation

    PubMed Central

    Wang, Hsiao-Wei; Cheng, Chung-Wei; Li, Ching-Wen; Chang, Han-Wei; Wu, Ping-Han; Wang, Gou-Jen

    2012-01-01

    One of the persistent challenges confronting tissue engineering is the lack of intrinsic microvessels for the transportation of nutrients and metabolites. An artificial microvascular system could be a feasible solution to this problem. In this study, the femtosecond laser ablation technique was implemented for the fabrication of pillared microvessel scaffolds of polylactic-co-glycolic acid (PLGA). This novel scaffold facilitates implementation of the conventional cell seeding process. The progress of cell growth can be observed in vitro by optical microscopy. The problems of becoming milky or completely opaque with the conventional PLGA scaffold after cell seeding can be resolved. In this study, PLGA microvessel scaffolds consisting of 47 μm × 80 μm pillared branches were produced. Results of cell culturing of bovine endothelial cells demonstrate that the cells adhere well and grow to surround each branch of the proposed pillared microvessel networks. PMID:22605935

  10. Microencapsulation of curcumin in PLGA microcapsules by coaxial flow focusing

    NASA Astrophysics Data System (ADS)

    Lei, Fan; Si, Ting; Luo, Xisheng; Xu, Ronald X.

    2014-03-01

    Curcumin-loaded PLGA microcapsules are fabricated by a liquid-driving coaxial flow focusing device. In the process, a stable coaxial cone-jet configuration is formed under the action of a coflowing liquid stream and the coaxial liquid jet eventually breaks up into microcapsules because of flow instability. This process can be well controlled by adjusting the flow rates of three phases including the driving PVA water solution, the outer PLGA ethyl acetate solution and the inner curcumin propylene glycol solution. Confocal and SEM imaging methods clearly indicate the core-shell structure of the resultant microcapsules. The encapsulation rate of curcumin in PLGA is measured to be more than 70%, which is much higher than the tranditional methods such as emulsion. The size distribution of resultant microcapsules under different conditions is presented and compared. An in vitro release simulation platform is further developed to verify the feasibility and reliability of the method.

  11. Formulation and evaluation of poly(lactic-co-glycolic acid) microspheres loaded with an altered collagen type II peptide for the treatment of rheumatoid arthritis.

    PubMed

    He, Jintian; Li, Huiqi; Liu, Chao; Wang, Gaizhen; Ge, Lan; Ma, Shufen; Huang, Lijing; Yan, Shaofeng; Xu, Xiaohong

    2015-01-01

    The aim of this research was to evaluate the potential of water-in-oil-in-water (w/o/w) and solid-in-oil-in-water (s/o/w) emulsification techniques to prepare the altered collagen type II peptide AP268-270 (ACTP)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres to make ACTP more convenient as an rheumatoid arthritis treatment. Microspheres produced by the s/o/w method had higher drug encapsulation efficiency (69.7-79.8%) than those prepared by the w/o/w method (21.8-39.3%). In vitro drug release was influenced by the microencapsulation technique, molecular weight, and composition of the polymer. After intramuscular injection of the optimal formulation to Lewis rats, the concentration of ACTP peptide in serum reached its maximum level on day 3 and then remained nearly stable for approximately 4 weeks. In a collagen-induced arthritis rat model, a single intramuscular injection of ACTP-loaded PLGA microspheres had comparable efficacy to the intravenous injection of ACTP peptide solution once every other day.

  12. Long-Acting Anticoagulant Rodenticide (Superwarfarin) Poisoning: A Review of Its Historical Development, Epidemiology, and Clinical Management.

    PubMed

    King, Nathan; Tran, Minh-Ha

    2015-10-01

    Long-acting anticoagulant rodenticides (LAARs) inhibit vitamin K epoxide reductase (VKOR). Related bleeding may present a diagnostic challenge and require administration of blood component therapy, hemostatic agents, and vitamin K. This article intends to provide the reader a comprehensive understanding of LAAR poisoning. An exhaustive literature search of PubMed, Science Direct, US National Library of Medicine Toxicology Data Network, and Google Scholar yielded 174 reported cases of LAAR poisoning from which clinical data were extracted and reviewed. In addition, 25 years of epidemiologic data from the American Association of Poison Control Centers was reviewed. In the United States, on average, there were 10413 exposures reported with 2750 patients treated annually. For 25 years, there were 315951 exposures reported with nearly 90% among children and more than 100000 patients treated in a health care facility. Fortunately, only 2% of all exposures result in morbidity or mortality. Inhalational, transcutaneous, and oral routes of exposure have been documented. Most exposures are unintentional. The most frequently reported bleeding sites are mucocutaneous, with hematuria being the most common feature. Deaths were most commonly associated with intracranial hemorrhage. Long-acting anticoagulant rodenticide-induced paradoxical thrombosis and thrombotic complications accompanying hemostatic therapy have also been observed. Most patients present with coagulation assay values beyond measurable limits. Long-acting anticoagulant rodenticides have an extremely high affinity for VKOR compared with warfarin, characterized by rebound coagulopathy and bleeding after initial treatment and the need for high-dose, long-term therapy with vitamin K1. Treatment of acute hemorrhagic symptoms often required intravenous vitamin K1 in excess of 50 to 100 mg; chronic maintenance with 100 mg PO vitamin K1 daily was the most frequently used dose required to suppress coagulopathy. Treatment

  13. Preparation and in vitro evaluation of thienorphine-loaded PLGA nanoparticles.

    PubMed

    Yang, Yang; Xie, Xiang Yang; Mei, Xing Guo

    2016-01-01

    Poly (d,l-lactic-co-glycolide) nanoparticles (PLGA-NPs) have attracted considerable interest as new delivery vehicles for small molecules, with the potential to overcome issue such as poor drug solubility and cell permeability. However, their negative surface charge decreases bioavailability under oral administration. Recently, cationically modified PLGA-NPs has been introduced as novel carriers for oral delivery. In this study, our aim was to introduce and evaluate the physiochemical characteristics and bioadhesion of positively charged chitosan-coated PLGA-NPs (CS-PLGA-NPs), using thienorphine as a model drug. These results indicated that both CS-PLGA-NPs and PLGA-NPs had a narrow size distribution, averaging less than 130 nm. CS-PLGA-NPs was positively charged (+42.1 ± 0.4 mV), exhibiting the cationic nature of chitosan, whereas PLGA-NPs showed a negative surface charge (-2.01 ± 0.3 mV). CS-PLGA-NPs exhibited stronger bioadhesive potency than PLGA-NPs. Furthermore, the transport of thienorphine-CS-PLGA-NPs by Caco-2 cells was higher than thienorphine-PLGA-NPs or thienorphine solution. CS-PLGA-NPs were also found to significantly enhance cellular uptake compared with PLGA-NPs on Caco-2 cells. An evaluation of cytotoxicity showed no increase in toxicity in either kind of nanoparticles during the formulation process. The study proves that CS-PLGA-NPs can be used as a vector in oral drug delivery systems for thienorphine due to its positive surface charge and bioadhesive properties.

  14. Efficacy of long-acting oxytetracycline alone or in combination with streptomycin for treatment of Brucella ovis infection of rams.

    PubMed

    Marín, C M; Jiménez de Bagués, M P; Barberán, M; Blasco, J M

    1989-04-01

    Twenty-four rams inoculated with Brucella ovis by conjunctival and preputial routes were treated with a long-acting oxytetracycline alone or in combination with dihydrostreptomycin sulfate. The combined treatment eliminated Brucella ovis from 11 of 12 (91.6%) treated rams. Only 4 of 12 (33.3%) rams treated with oxytetracycline alone were bacteriologically negative. Neither treatment resolved clinical epididymitis in 2 rams affected before treatment. Many rams had pathologic lesions in the epididymis and ampullae, which limited the efficacy of antibiotic treatment.

  15. New developments in long-acting reversible contraception: the promise of intrauterine devices and implants to improve family planning services.

    PubMed

    Turok, David K; Gawron, Lori M; Lawson, Samantha

    2016-11-01

    After decades of having the developed world's highest rates of unintended pregnancy, the United States finally shows signs of improvement. This progress is likely due in large part to increased use of highly effective long-acting reversible methods of contraception. These methods can be placed and do not require any maintenance to provide years of contraception as effective as sterilization. Upon removal, fertility returns to baseline rates. This article addresses advances in both software-improved use and elimination of barriers to provide these methods; and hardware-novel delivery systems and devices.

  16. Microspheres and their methods of preparation

    DOEpatents

    Bose, Anima B; Yang, Junbing

    2015-03-24

    Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

  17. Long-Acting Injectable Antipsychotics for Prevention of Relapse in Bipolar Disorder: A Systematic Review and Meta-Analyses of Randomized Controlled Trials

    PubMed Central

    Oya, Kazuto; Iwata, Nakao

    2016-01-01

    Background: This meta-analysis of randomized controlled trials aimed to examine the advantages of long-acting injectable antipsychotics over placebo or oral medications regarding efficacy and safety for patients with bipolar disorder. Methods: Two categorical meta-analyses of randomized controlled trials were performed to compare study-defined relapse rate (primary), discontinuation rates, and individual adverse events: (1) risperidone-long-acting injectable vs placebo, and (2) long-acting injectable antipsychotics vs oral medications. Results: We identified 7 randomized controlled trials (n=1016; long-acting injectable antipsychotics [flupenthixol (1 randomized controlled trial) and risperidone (6 randomized controlled trials)=449]; oral medications [mood stabilizers, antidepressants, antipsychotic, or any combination of these agents=283]; and placebo=284). Risperidone-long-acting injectable antipsychotic was superior to placebo for study-defined relapse rate (risk ratio=0.63, P<.0001), relapse of manic symptoms (risk ratio=0.42, P<.00001), and all-cause discontinuation (risk ratio=0.75, P=.007). Risperidone-long-acting injectable was associated with higher incidence of prolactin-related adverse events (risk ratio=4.82, P=.001) and weight gain (risk ratio=3.80, P<.0001) than placebo. The pooled long-acting injectable antipsychotics did not outperform oral medications regarding primary outcome but with significant heterogeneity (I2=74%). Sensitivity analysis, including only studies with rapid cycling or high frequency of relapse patients, revealed that long-acting injectable antipsychotics were superior compared to oral medications (I2=0%, RR=0.58, P=.0004). However, the comparators in this sensitivity analysis did not include second-generation antipsychotic monotherapy. In sensitivity analysis, including only studies with second-generation antipsychotic monotherapy as the comparator, long-acting injectable antipsychotics did not outperform second

  18. Quantitative three-dimensional analysis of poly (lactic-co-glycolic acid) microsphere using hard X-ray nano-tomography revealed correlation between structural parameters and drug burst release.

    PubMed

    Huang, Xiaozhou; Li, Na; Wang, Dajiang; Luo, Yuyan; Wu, Ziyu; Guo, Zhefei; Jin, Qixing; Liu, Zhuying; Huang, Yafei; Zhang, Yongming; Wu, Chuanbin

    2015-08-10

    The objective of this study was to investigate the use of transmission hard X-ray nano-computed-tomography (nano-CT) for characterization of the pore structure and drug distribution in poly (lactic-co-glycolic acid) (PLGA) microspheres encapsulating bovine serum albumin and to study the correlation between drug distribution and burst release. The PLGA microspheres were fabricated using a double-emulsion method. The results of pore structure analysis accessed with nano-CT were compared with those acquired by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Surface pore interconnectivity and surface protein interconnectivity were obtained using combined nano-CT and pixel analysis. The correlation between surface protein interconnectivity with the initial burst release across various tested formulations was also analyzed. The size, shape, and distribution of the pores and protein could be clearly observed in the whole microsphere using nano-CT, whereas only the sectional information was observed using SEM or CLSM. Interconnected pores and surface connected pores could be clearly distinguished in nano-CT, which enables the quantitative analysis of surface pore interconnectivity and surface protein interconnectivity. The surface protein interconnectivity in different formulations correlated well with the burst release at 5-10h. Nano-CT provided a nondestructive, high-resolution, and three-dimensional analysis method to characterize the porous microsphere.

  19. Interaction of PLGA and trimethyl chitosan modified PLGA nanoparticles with mixed anionic/zwitterionic phospholipid bilayers studied using molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Novak, Brian; Astete, Carlos; Sabliov, Cristina; Moldovan, Dorel

    2012-02-01

    Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable polymer. Nanoparticles of PLGA are commonly used for drug delivery applications. The interaction of the nanoparticles with the cell membrane may influence the rate of their uptake by cells. Both PLGA and cell membranes are negatively charged, so adding positively charged polymers such as trimethyl chitosan (TMC) which adheres to the PLGA particles improves their cellular uptake. The interaction of 3 nm PLGA and TMC-modified-PLGA nanoparticles with lipid bilayers composed of mixtures of phosphatidylcholine and phosphatidylserine lipids was studied using molecular dynamics simulations. The free energy profiles as function of nanoparticles position along the normal direction to the bilayers were calculated, the distribution of phosphatidylserine lipids as a function of distance of the particle from the bilayer was calculated, and the time scale for particle motion in the directions parallel to the bilayer surface was estimated.

  20. Multilayered polymer microspheres by thermal imprinting during microsphere growth.

    PubMed

    Takekoh, Ryu; Li, Wen-Hui; Burke, Nicholas A D; Stöver, Harald D H

    2006-01-11

    Modulation of the polymerization temperature in precipitation polymerizations was used to form onion-type polymer microspheres consisting of multiple nested layers. Specifically, the copolymerization of chloromethylstyrene and divinylbenzene-55 in acetonitrile, at temperatures ramping between 65 and 75 degrees C, led to monodisperse, cross-linked microspheres of about 10 mum diameter that have radial density profiles closely reflecting the thermal profiles used. This thermal imprinting is attributed to the copolymer formed being close to its theta point during the polymerization. As the microspheres grow by continuously capturing oligomers from solution, the resulting transient surface gel layer expands and contracts with temperature, and thus records the reaction temperature profile in the form of a corresponding density profile, even as it cross-links.

  1. Development and in vitro characterization of poly(lactide-co-glycolide) microspheres loaded with an antibacterial natural drug for the treatment of long-term bacterial infections

    PubMed Central

    Reinbold, Jochen; Hierlemann, Teresa; Hinkel, Helena; Müller, Ingrid; Maier, Martin E; Weindl, Tobias; Schlensak, Christian; Wendel, Hans Peter; Krajewski, Stefanie

    2016-01-01

    Biodegradable polymers, especially poly(lactide-co-glycolide) (PLGA), have good biocompatibility and toxicological properties. In combination with active ingredients, a specialized drug delivery system can be generated. The aim of the present study was to develop a drug delivery system consisting of PLGA microspheres loaded with the natural active ingredient totarol, which has several antimicrobial mechanisms. Totarol, isolated from the Podocarpus totara tree, was purified using column chromatography, and the eluate was checked for purity using thin layer chromatography. The spherically shaped microspheres with mean diameters of 147.21±3.45 µm and 131.14±3.69 µm (totarol-loaded and -unloaded microspheres, respectively) were created using the single emulsion evaporation method. Furthermore, the encapsulation efficiency, in a range of 84.72%±6.68% to 92.36%±0.99%, was measured via UV/vis spectroscopy. In a 90-day in vitro drug release study, the release of totarol was investigated by UV/vis spectroscopy as well, showing a release of 53.76%. The toxicity on cells was determined using BJ fibroblasts or Human Embryonic Kidney cells and an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, which showed no influence on the cell growth. The minimal inhibitory concentration was ascertained. A totarol concentration between 64 µg/mL and 128 µg/mL was necessary to inhibit the bacterial growth over a period of 24 hours. Biofilm formation on the surface of totarol-loaded microspheres was determined using transmission electron microscopy. No biofilm formation could be detected, even if the totarol concentration was below the minimal inhibitory concentration. The hemocompatibility investigations on various markers with fresh heparinized blood (1.5 IU/mL) showed that totarol and totarol-loaded microspheres have no influence on different blood parameters. The PLGA microspheres characterized by slow release of totarol and great entrapment efficiency represent

  2. A biodegradable polymeric system for peptide–protein delivery assembled with porous microspheres and nanoparticles, using an adsorption/infiltration process

    PubMed Central

    Alcalá-Alcalá, Sergio; Urbán-Morlán, Zaida; Aguilar-Rosas, Irene; Quintanar-Guerrero, David

    2013-01-01

    A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(d,l-lactide-co-glycolide) (PLGA) was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL) in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg) by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres). Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95%) and a slower release rate were seen (~20% of released leuprolide in 12 hours) when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles). Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours. In contrast, the systems assembled in this study released less than 44% of the loaded drug during the same period of time. The observed release profiles denoted a Fickian diffusion that fit Higuchi’s model (t1/2). The manufacturing process presented here may be useful as a potential alternative for formulating

  3. Tracking the in vivo release of bioactive NRG from PLGA and PEG-PLGA microparticles in infarcted hearts.

    PubMed

    Pascual-Gil, S; Simón-Yarza, T; Garbayo, E; Prosper, F; Blanco-Prieto, M J

    2015-12-28

    The growth factor neuregulin (NRG) is one of the most promising candidates in protein therapy as potential treatment for myocardial infarction (MI). In the last few years, biomaterial based delivery systems, such as polymeric microparticles (MPs) made of poly(lactic co glycolic acid) and polyethylene glycol (PLGA and PEG-PLGA MPs), have improved the efficacy of protein therapy in preclinical studies. However, no cardiac treatment based on MPs has yet been commercialized since this is a relatively new field and total characterization of polymeric MPs remains mandatory before they reach the clinical arena. Therefore, the objective of this study was to characterize the in vivo release, bioactivity and biodegradation of PLGA and PEG-PLGA MPs loaded with biotinylated NRG in a rat model of MI. The effect of PEGylation in the clearance of the particles from the cardiac tissue was also evaluated. Interestingly, MPs were detected in the cardiac tissue for up to 12 weeks after administration. In vivo release analysis showed that bNRG was released in a controlled manner throughout the twelve week study. Moreover, the biological cardiomyocyte receptor (ErbB4) for NRG was detected in its activated form only in those animals treated with bNRG loaded MPs. On the other hand, the PEGylation strategy was effective in diminishing phagocytosis of these MPs compared to noncoated MPs in the long term (12 weeks after injection). Taking all this together, we report new evidence in favor of the use of polymeric PLGA and PEG-PLGA MPs as delivery systems for treating MI, which could be soon included in clinical trials.

  4. Biocompatibility and characteristics of chitosan/cellulose acetate microspheres for drug delivery

    NASA Astrophysics Data System (ADS)

    Zhou, Hui-Yun; Zhou, Dong-Ju; Zhang, Wei-Fen; Jiang, Ling-Juan; Li, Jun-Bo; Chen, Xi-Guang

    2011-12-01

    In this work, chitosan/cellulose acetate microspheres (CCAM) were prepared by the method of W/O/W emulsion with no toxic reagents. The microspheres were spherical, free flowing, and non-aggregated, which had a narrow size distribution. More than 90% of the microspheres had the diameter ranging from 200 to 280 μm. The hemolytic analysis indicated that CCAM was safe and had no hemolytic effect. The implanted CCAM did not produce any significant changes in the hematology of Sprague-Dawley (SD) rats, such as white blood cell, red blood cell, platelet, and the volume of hemoglobin. In addition, the levels of serum alanine aminotransferase, blood urea nitrogen, and creatinine had no obvious changes in SD rats implanted with CCAM, surger thread, or normal SD rats without any implantation. Thus, the CCAM had good blood compatibility and had no hepatotoxicity or renal toxicity to SD rats. Furthermore, CCAM with or without the model drug had good tissue compatibility with respect to the inflammatory reaction in SD rats and showed no significant difference from that of SD rats implanted with surgery thread. CCAM shows promise as a long-acting delivery system, which had good biocompatibility and biodegradability.

  5. Oral Delivery of DMAB-Modified Docetaxel-Loaded PLGA-TPGS Nanoparticles for Cancer Chemotherapy

    NASA Astrophysics Data System (ADS)

    Chen, Hongbo; Zheng, Yi; Tian, Ge; Tian, Yan; Zeng, Xiaowei; Liu, Gan; Liu, Kexin; Li, Lei; Li, Zhen; Mei, Lin; Huang, Laiqiang

    2011-12-01

    Three types of nanoparticle formulation from biodegradable PLGA-TPGS random copolymer were developed in this research for oral administration of anticancer drugs, which include DMAB-modified PLGA nanoparticles, unmodified PLGA-TPGS nanoparticles and DMAB-modified PLGA-TPGS nanoparticles. Firstly, the PLGA-TPGS random copolymer was synthesized and characterized. DMAB was used to increase retention time at the cell surface, thus increasing the chances of particle uptake and improving oral drug bioavailability. Nanoparticles were found to be of spherical shape with an average particle diameter of around 250 nm. The surface charge of PLGA-TPGS nanoparticles was changed to positive after DMAB modification. The results also showed that the DMAB-modified PLGA-TPGS nanoparticles have significantly higher level of the cellular uptake than that of DMAB-modified PLGA nanoparticles and unmodified PLGA-TPGS nanoparticles. In vitro, cytotoxicity experiment showed advantages of the DMAB-modified PLGA-TPGS nanoparticle formulation over commercial Taxotere® in terms of cytotoxicity against MCF-7 cells. In conclusion, oral chemotherapy by DMAB-modified PLGA-TPGS nanoparticle formulation is an attractive and promising treatment option for patients.

  6. Dose determination of the persistent activity of moxidectin long-acting injectable formulations against various nematode species in cattle.

    PubMed

    Yazwinski, T A; Williams, J C; Smith, L L; Tucker, C; Loyacano, A F; Derosa, A; Peterson, P; Bruer, D J; Delay, R L

    2006-04-30

    The effectiveness, safety and production-enhancing benefit (improved weight gains) of moxidectin long-acting injection given subcutaneously in the ear at the rates of 0.75, 1.0 and 1.5mg/kg bw were evaluated in three studies under common protocol. The only adverse reaction to treatment was a mild (<2 tablespoons in volume), and for the most part transient (<28 days for the treatment rate of 1.0mg/kg bw) injection site swelling as noted in a minority of the animals (12.2% of the animals treated at the rate of 1.0mg/kg bw). Regardless of study site, post-treatment interval or dose rate, average daily gains were improved over control cattle by approximately 33%. Reductions in strongyle EPG counts relative to controls were > or = 90% for all dose rates of moxidectin for a post-treatment period of 42 days (Wisconsin), 84 days (Arkansas) and 140 days (Louisiana). In Arkansas and Louisiana, the majority (>80%) of post-treatment strongyle eggs, as determined by coproculture, were Cooperia spp. As determined by sequential necropsies, periods of continuous, post-treatment protection (> or = 90% efficacy in at least two out of three studies) for moxidectin long-acting injection given at the rate of 1.0 mg/kg bw were 90 days (adult Haemonchus spp.), 120 days (Dictyocaulus viviparus and adult Ostertagia and Oesophagostomum) and 150 days (Ostertagia spp. EL4).

  7. Potentiation of local anesthetic activity of neosaxitoxin with bupivacaine or epinephrine: development of a long-acting pain blocker.

    PubMed

    Rodriguez-Navarro, Alberto J; Lagos, Marcelo; Figueroa, Cristian; Garcia, Carlos; Recabal, Pedro; Silva, Pamela; Iglesias, Veronica; Lagos, Nestor

    2009-11-01

    Local anesthetics effectively block and relieve pain, but with a relatively short duration of action, limiting its analgesic effectiveness. Therefore, a long-acting local anesthetic would improve the management of pain, but no such agent is yet available for clinical use. The aim of this study is to evaluate the potentiation of the anesthetic effect of neosaxitoxin, with bupivacaine or epinephrine in a randomized double-blind clinical trial. Ten healthy males were subcutaneously injected into the left and right forearms with a randomized pair of the following treatments: (i) bupivacaine (5 mg); (ii) neosaxitoxin (10 microg); (iii) neosaxitoxin (10 microg) plus bupivacaine (5 mg), and (iv) neosaxitoxin (10 microg) plus epinephrine (1:100.000), but all participant received all four formulations (in 2 ml; s.c.), with 1 month elapsing between the two round of experiments. A validated sensory and pain paradigm was used for evaluating the effect of the treatment 0-72 h after the injections, measuring sensory, pain, and mechanical touch perception threshold. The duration of the effect produced by combined treatments was longer than that by the single drugs. In conclusion, bupivacaine and epinephrine potentiate the local anesthetic effect of neosaxitoxin in humans when co-injected subcutaneously. The present results support the idea that neosaxitoxin is a new long-acting local pain blocker, with highly potential clinical use.

  8. Pharmacokinetics and D2 receptor occupancy of long-acting injectable risperidone (Risperdal Consta) in patients with schizophrenia.

    PubMed

    Gefvert, Ola; Eriksson, Bo; Persson, Per; Helldin, Lars; Björner, Annika; Mannaert, Erik; Remmerie, Bart; Eerdekens, Mariëlle; Nyberg, Svante

    2005-03-01

    Thirteen patients with schizophrenia received injections of 25, 50, or 75 mg of long-acting risperidone every 2 wk. Brain D2 receptor occupancy was assessed with [11C]raclopride 2 wk after the last (fifth) injection (day 71) in seven subjects and 2 wk after the third injection (day 44) in one subject. Stable plasma concentrations were reached after the third injection and steady-state concentrations of the active moiety (risperidone + 9-hydroxyrisperidone) after the fourth injection. Steady-state plasma concentrations were maintained for 4-5 wk after the last injection and then declined rapidly. After injections of 25, 50 and 75 mg on day 44 or day 71, D2 receptor occupancy ranged from 25-48%, 59-83% and 62-72% respectively, while plasma active-moiety levels ranged from 4.4-8.8, 15.0-31.1 and 22.5-26.3 ng/ml respectively. The results indicate that brain D2 receptor occupancy at steady state after injections of long-acting risperidone was in the range found in patients effectively treated with 2-6 mg of oral risperidone.

  9. LAPS-FSH: a new and effective long-acting follicle-stimulating hormone analogue for the treatment of infertility.

    PubMed

    Jung, Sunyoung; Park, Youngjin; Kim, YoungHoon; Kim, Yu Yon; Choi, Hyun-Ji; Son, Woo-Chan; Kwon, SeChang

    2014-10-01

    Although several long-acting follicle-stimulating hormone (FSH) therapies have been developed to enhance the ovarian response, a disadvantage of FSH therapy is its relatively short half-life, which requires women to receive one to two injections per day for almost 2 weeks. In the present study, we developed a novel FSH analogue by conjugating recombinant human FSH (rhFSH) and the constant region of the human immunoglobulin G4 fragment via non-peptidyl linkers. The efficacy of the FSH analogue was evaluated in vitro by cAMP level assessments, pharmacokinetic studies and a determination of ovarian weight and by comparing these findings with the results from other FSH analogues. In addition, the total number of antral and Graafian follicles was determined after 7 days of treatment with control, 6µgkg(-1) follitropin β, 6, 12 or 42µgkg(-1) corifollitropin α or 3, 6 or 12µgkg(-1) long acting protein/peptide discovery-follicle-stimulating hormone (LAPS-FSH). As a result, the animals treated with 12µgkg(-1) LAPS-FSH produced additional and larger healthy follicles. These data demonstrate that LAPS-FSH promotes growth and inhibits atresia of the ovarian follicle compared with other available drugs, suggesting that our new drug enhances the efficacy and duration of treatment. It is expected that our new FSH analogue will result in a higher chance of pregnancy in patients who are unresponsive to other drugs.

  10. Cytotoxicity and intracellular fate of PLGA and chitosan-coated PLGA nanoparticles in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells.

    PubMed

    Trif, Mihaela; Florian, Paula E; Roseanu, Anca; Moisei, Magdalena; Craciunescu, Oana; Astete, Carlos E; Sabliov, Cristina M

    2015-11-01

    Polymeric nanoparticles (NPs) are known to facilitate intracellular uptake of drugs to improve their efficacy, with minimum bioreactivity. The goal of this study was to assess cellular uptake and trafficking of PLGA NPs and chitosan (Chi)-covered PLGA NPs in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells. Both PLGA and Chi-PLGA NPs were not cytotoxic to the studied cells at concentrations up to 2500 μg/mL. The positive charge conferred by the chitosan deposition on the PLGA NPs improved NPs uptake by MDBK cells. In this cell line, Chi-PLGA NPs colocalized partially with early endosomes compartment and showed a more consistent perinuclear localization than PLGA NPs. Kinetic uptake of PLGA NPs by Colo 205 was slower than that by MDBK cells, detected only at 24 h, exceeding that of Chi-PLGA NPs. This study offers new insights on NP interaction with target cells supporting the use of NPs as novel nutraceuticals/drug delivery systems in metabolic disorders or cancer therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3599-3611, 2015.

  11. Polarization Dependent Whispering Gallery Modes in Microspheres

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  12. Modeling the Formation of Polyimide Microspheres

    NASA Technical Reports Server (NTRS)

    Pipes, R. B.; Weiser, E. S.; Gonsoulin, B.; Hubert, P.

    2002-01-01

    High temperature polyimide microspheres have been developed from polyimide solid residuum by a simple inflation process. Microspheres have been fabricated from several polyimide precursors through the use of a circulating air oven. Microsphere formation and final physical property characterization have been limited to simple mechanical and thermal testing. The present paper focuses on developing an understanding of microsphere formation through simple geometric rules for an incompressible polymeric material and microscopic observations of precursor residuum inflation. Inflation kinematics of the hollow polyimide microspheres as a function of time and temperature is discussed.

  13. [Transport of PLGA nanoparticles across Caco-2/HT29-MTX co-cultured cells].

    PubMed

    Wen, Zhen; Li, Gang; Lin, Dong-Hai; Wang, Jun-Teng; Qin, Li-Fang; Guo, Gui-Ping

    2013-12-01

    The present study is to establish Caco-2/HT29-MTX co-cultured cells and investigate the transport capability of PLGA nanoparticles with different surface chemical properties across Caco-2/HT29-MTX co-cultured cells. PLGA-NPs, mPEG-PLGA-NPs and chitosan coated PLGA-NPs were prepared by nanoprecipitation method using poly(lactic-co-glycolic acid) as carrier material with surface modified by methoxy poly(ethylene glycol) and chitosan. The particle size and zeta potential of nanoparticles were measured by dynamic light scattering. Coumarin 6 was used as a fluorescent marker in the transport of nanoparticles investigated by confocal laser scanning microscopy. The transport of furanodiene (FDE) loaded nanoparticles was quantitively determined by high performance liquid chromatography. Colchicine and nocodazole were used in the transport study to explore the involved endocytosis mechanisms of nanoparticles. Distribution of the tight junction proteins ZO-1 was also analyzed by immunofluorescence staining. The results showed that the nanoparticles dispersed uniformly. The zeta potential of PLGA-NPs was negative, the mPEG-PLGA-NPs was close to neutral and the CS-PLGA-NPs was positive. The entrapment efficiency of FDE in all nanoparticles was higher than 75%. The transport capability of mPEG-PLGA-NPs across Caco-2/HT29-MTX co-cultured cells was higher than that of PLGA-NPs and CS-PLGA-NPs. Colchicine and nocodazole could significantly decrease the transport amount of nanoparticles. mPEG-PLGA-NPs could obviously reduce the distribution of ZO-1 protein than PLGA-NPs and CS-PLGA-NPs. The transport mechanism of PLGA-NPs and mPEG-PLGA-NPs were indicated to be a combination of endocytosis and paracellular way, while CS-PLGA-NPs mainly relied on the endocytosis way. PEG coating could shield the surface charge and enhance the hydrophilicity of PLGA nanoparticles, which leads mPEG-PLGA-NPs to possess higher anti-adhesion activity. As a result, mPEG-PLGA-NPs could penetrate the mucus

  14. Production of monodisperse, polymeric microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Rhim, Won-Kyu (Inventor); Hyson, Michael T. (Inventor); Chang, Manchium (Inventor)

    1990-01-01

    Very small, individual polymeric microspheres with very precise size and a wide variation in monomer type and properties are produced by deploying a precisely formed liquid monomer droplet, suitably an acrylic compound such as hydroxyethyl methacrylate into a containerless environment. The droplet which assumes a spheroid shape is subjected to polymerizing radiation such as ultraviolet or gamma radiation as it travels through the environment. Polymeric microspheres having precise diameters varying no more than plus or minus 5 percent from an average size are recovered. Many types of fillers including magnetic fillers may be dispersed in the liquid droplet.

  15. Microsphere-based gradient implants for osteochondral regeneration: a long-term study in sheep

    PubMed Central

    Mohan, Neethu; Gupta, Vineet; Sridharan, Banu Priya; Mellott, Adam J; Easley, Jeremiah T; Palmer, Ross H; Galbraith, Richard A; Key, Vincent H; Berkland, Cory J; Detamore, Michael S

    2015-01-01

    Background: The microfracture technique for cartilage repair has limited ability to regenerate hyaline cartilage. Aim: The current study made a direct comparison between microfracture and an osteochondral approach with microsphere-based gradient plugs. Materials & methods: The PLGA-based scaffolds had opposing gradients of chondroitin sulfate and β-tricalcium phosphate. A 1-year repair study in sheep was conducted. Results: The repair tissues in the microfracture were mostly fibrous and had scattered fissures with degenerative changes. Cartilage regenerated with the gradient plugs had equal or superior mechanical properties; had lacunated cells and stable matrix as in hyaline cartilage. Conclusion: This first report of gradient scaffolds in a long-term, large animal, osteochondral defect demonstrated potential for equal or better cartilage repair than microfracture. PMID:26418471

  16. Aqueous Two Phase System Assisted Self-Assembled PLGA Microparticles

    NASA Astrophysics Data System (ADS)

    Yeredla, Nitish; Kojima, Taisuke; Yang, Yi; Takayama, Shuichi; Kanapathipillai, Mathumai

    2016-06-01

    Here, we produce poly(lactide-co-glycolide) (PLGA) based microparticles with varying morphologies, and temperature responsive properties utilizing a Pluronic F127/dextran aqueous two-phase system (ATPS) assisted self-assembly. The PLGA polymer, when emulsified in Pluronic F127/dextran ATPS, forms unique microparticle structures due to ATPS guided-self assembly. Depending on the PLGA concentration, the particles either formed a core-shell or a composite microparticle structure. The microparticles facilitate the simultaneous incorporation of both hydrophobic and hydrophilic molecules, due to their amphiphilic macromolecule composition. Further, due to the lower critical solution temperature (LCST) properties of Pluronic F127, the particles exhibit temperature responsiveness. The ATPS based microparticle formation demonstrated in this study, serves as a novel platform for PLGA/polymer based tunable micro/nano particle and polymersome development. The unique properties may be useful in applications such as theranostics, synthesis of complex structure particles, bioreaction/mineralization at the two-phase interface, and bioseparations.

  17. Patterns of faecal nematode egg shedding after treatment of sheep with a long-acting formulation of moxidectin.

    PubMed

    Crilly, James Patrick; Jennings, Amy; Sargison, Neil

    2015-09-15

    Much of the current information on the effects of long-acting anthelmintics on nematode populations derives either from research farms or mathematical models. A survey was performed with the aim of establishing how moxidectin is currently being used on sheep farms in the south-east of Scotland. A study was undertaken on a subsection of the surveyed farms to examine the effects of long-acting moxidectin treatments in both spring and autumn on faecal nematode egg output. The survey showed that whole flock treatments of injectable 2% moxidectin were used to control sheep scab on 21% of farms. Injectable 2% moxidectin and oral moxidectin were used to control the periparturient rise in faecal nematode egg shedding by ewes on 13% and 55% of farms respectively. The effects of injectable 2% moxidectin treatment on faecal nematode egg shedding post-treatment in both the autumn and spring were investigated by faecal nematode egg counts at the time of treatment and at 2-weekly interval thereafter on eight and six farms in the autumn and spring, respectively. Faecal egg shedding recommenced at 8 weeks (autumn) and 4 weeks (spring) post-treatment. Counts increased to a peak and then declined. The mean (95% confidence interval) peak counts post-treatment were 2.8 (0.6, 5.1), 3.6 (1.7, 5.5) and 53.5 (25.1, 82.0) eggs per gram (EPG) for autumn-treated ewes, autumn-treated lambs and spring-treated ewes respectively. The spring treated sheep showed a statistically significantly earlier return to faecal egg shedding (p=0.0125, p=0.0342) compared to both other groups, statistically significantly higher peak in egg counts than the autumn treated sheep (p<0.001) and a statistically significantly longer period of positive egg counts (p=0.0148). There was no statistically significant difference in the timing of the peak FECs between autumn and spring (p=0.211). The FECs of all groups of sheep treated with an injectable long-acting formulation of moxidectin became positive earlier than

  18. Long-acting bronchodilators with or without inhaled corticosteroids and 30-day readmission in patients hospitalized for COPD

    PubMed Central

    Bishwakarma, Raju; Zhang, Wei; Kuo, Yong-Fang; Sharma, Gulshan

    2017-01-01

    Background The ability of a long-acting muscarinic antagonist (LAMA) and long-acting beta 2 agonists (LABAs; long-acting bronchodilators, LABDs) with or without inhaled corticosteroids (ICSs) to reduce early readmission in hospitalized patients with COPD is unknown. Methods We studied a 5% sample of Medicare beneficiaries enrolled in Medicare parts A, B and D and hospitalized for COPD in 2011. We examined prescriptions filled for LABDs with or without ICSs (LABDs±ICSs) within 90 days prior to and 30 days after hospitalization. Primary outcome was the 30-day readmission rate between “users” and “nonusers” of LABDs±ICSs. Propensity score matching and sensitivity analysis were performed by limiting analysis to patients hospitalized for acute exacerbation of COPD (AECOPD). Among 6,066 patients hospitalized for COPD, 3,747 (61.8%) used LABDs±ICSs during the specified period. The “user” and “nonuser” groups had similar rates of all-cause emergency room (ER) visits and readmissions within 30 days of discharge date (22.4% vs 20.7%, P-value 0.11; 18.0% vs 17.8%, P-value 0.85, respectively). However, the “users” had higher rates of COPD-related ER visits (5.3% vs 3.4%, P-value 0.0006), higher adjusted odds ratio (aOR) 1.47 (95% CI, 1.11–1.93) and readmission (7.8% vs 5.0%, P-value <0.0001 and aOR 1.48 [95% CI, 1.18–1.86]) than “nonusers”. After propensity score matching, the aOR of COPD-related ER visits was 1.45 (95% CI, 1.07–1.96) and that of readmission was 1.34 (95% CI, 1.04–1.73). The results were similar when restricted to patients hospitalized for AECOPD. Conclusion Use of LABDs±ICSs did not reduce 30-day readmissions in patients hospitalized for COPD. PMID:28203071

  19. Multi-arm histidine copolymer for controlled release of insulin from poly(lactide-co-glycolide) microsphere.

    PubMed

    Park, Wooram; Kim, Dongin; Kang, Han Chang; Bae, You Han; Na, Kun

    2012-12-01

    For long-term, sustained protein delivery, a new, star-shaped block copolymer composed of methoxy poly(ethylene glycol) (mPEG), branched oligoethylenimine (bOEI), and poly(l-histidine) (pHis) was synthesized via the multi-initiation and ring-opening polymerization (ROP) of His N-carboxy anhydride (NCA) on bOEI with a PEG conjugation. The resulting mPEG-bOEI-pHis (POH) had strong buffering capacity within the neutral-to-acidic pH range and was complexed with insulin (Ins) via an electrostatic attraction plus hydrophobic interactions, resulting in the formation of a dual-interaction complex (DIC, weight ratio 2) of approximately 30-60 nm in size. This DIC tolerated high salt concentrations without destabilization, supporting the existence of hydrophobic interactions, and protected Ins from the organic solvent/water interface. The DIC in poly(lactide-co-glycolide) microspheres (PLGA MS) as a long-term Ins delivery formulation was evenly distributed via a double-emulsion method. The DIC-loaded PLGA MS offered a higher Ins loading and a lower initial burst than Ins-loaded PLGA MS. This formulation possessed near zero-order release kinetics (for at least one month). In streptozotocin (STZ)-induced diabetic rats, a DIC-loaded PLGA MS formulation was able to maintain blood-glucose levels at 200-350 mg/dL for the first two weeks and even lower levels (100-200 mg/dL) for the next two weeks. Thus, a new POH polymer and its complex with a drug protein could have potential biological application as a long-term, sustained protein delivery system.

  20. [Experimental study on application recombinant human bone morphogenetic protein 2(rhBMP-2)/poly-lactide-co-glycolic acid (PLGA)/fibrin sealant(FS) on repair of rabbit radial bone defect].

    PubMed

    Fan, Zhongkai; Cao, Yang; Zhang, Zhe; Zhang, Mingchao; Lu, Wei; Tang, Lei; Yao, Qi; Lu, Gang

    2012-10-01

    This paper is aimed to investigate the repair of rabbit radial bone defect by the recombinant human bone morphogenetic protein 2/poly-lactideco-glycolic acid microsphere with fibrin sealant (rhBMP-2/PLGA/FS). The radial bone defect models were prepared using New Zealand white rabbits, which were randomly divided into 3 groups, experiment group which were injected with eMP-2/PLGA/FS at bone defect location, control group which were injected with FS at bone defect location, and blank control group without treatment. The ability of repairing bone defect was evaluated with X-ray radiograph. Bone mineral density in the defect regions was analysed using the level of ossification. The osteogenetic ability of repairing bone defect, the degradation of the material, the morphologic change and the bone formation were assessed by HE staining and Masson staining. The result showed that rhBMP-2/PLGA/FS had overwhelming superiority in the osteogenetic ability and quality of bone defect over the control group, and it could promote the repair of bone defect and could especially repair the radial bone defect of rabbit well. It may be a promising and efficient synthetic bone graft.

  1. Quantitative determination of amorphous nicardipine hydrochloride in long acting formula (NIC-LA) using light anhydrous silicic acid.

    PubMed

    Kohinata, Takeru; Fujii, Mitsuo; Nakamura, Souichiro; Hamada, Noritaka; Yonemochi, Etsuo; Terada, Katsuhide

    2004-12-01

    We investigated a method to quantitatively determine amorphous nicardipine hydrochloride (NIC) in the NIC-long acting formula (LA) model formulas prepared using NIC, light anhydrous silicic acid (LASA) and carboxymethylethylcellulose (CMEC). Consequently, since the quantity of total NIC in the formula can be determined by means of HPLC and crystal NIC can be determined by the differential scanning calorimetry (DSC) method because the heat of fusion (85.08 J/g) of NIC is constant and unaffected by excipients, we developed the HPLC-DSC method by which the quantity of amorphous NIC is calculated as the difference between the quantity of total NIC determined by HPLC and the quantity of crystal NIC determined by DSC. This practical HPLC-DSC method was confirmed to have good accuracy and reproducibility.

  2. Improving Access to Long-Acting Contraceptive Methods and Reducing Unplanned Pregnancy Among Women with Substance Use Disorders

    PubMed Central

    Black, Kirsten I.; Day, Carolyn A.

    2016-01-01

    Much has been written about the consequences of substance use in pregnancy, but there has been far less focus on the prevention of unintended pregnancies in women with substance use disorders (SUDs). We examine the literature on pregnancy incidence for women with SUDs, the clinical and economic benefits of increasing access to long-acting reversible contraceptive (LARC) methods in this population, and the current hurdles to increased access and uptake. High rates of unintended pregnancies and poor physical and psychosocial outcomes among women with SUDs underscore the need for increased access to, and uptake of, LARC methods among these women. A small number of studies that focused on improving access to contraception, especially LARC, via integrated contraception services predominantly provided in drug treatment programs were identified. However, a number of barriers remain, highlighting that much more research is needed in this area. PMID:27199563

  3. [Efficiency of a pharmaceutical care program for long-acting parenteral antipsychotics in the health area of Santiago de Compostela].

    PubMed

    Vázquez-Mourelle, Raquel; Parrondo, Carmen Durán; López-Pardo Pardo, Estrella; Carracedo-Martínez, Eduardo

    2016-01-01

    In the healthcare area of Santiago de Compostela (Spain), the therapeutic subgroup "other antipsychotics" represented the fifth largest outpatient expenditure in 2013. More than half of this expenditure corresponded to long-acting parenteral forms of paliperidone and risperidone. Over a 12-month period, the implementation of a pharmaceutical care program based on process management and coordination of actions between health professionals in both levels of care represented savings of € 636,391.01 for the organization and a direct saving of € 16,767.36 and 9,008 trips to the pharmacy for patients. This study shows the efficiency of the program, which was facilitated by its situation in an area of integrated management and the use the unified medical records and electronic prescription, elements that will enable the future implementation of similar programmes. The new registries and healthcare interventions will allow reliable evaluation of their effectiveness in terms of treatment adherence, relapses and hospitalisations.

  4. Provider Bias in Long-Acting Reversible Contraception (LARC) Promotion and Removal: Perceptions of Young Adult Women

    PubMed Central

    Kramer, Renee D.; Ryder, Kristin M.

    2016-01-01

    Long-acting reversible contraception (LARC) is effective and acceptable. However, concern exists about potential provider bias in LARC promotion. No study has documented contraceptive users’ attitudes toward or experiences with provider influence and bias regarding LARC. We collected qualitative data in 2014 to address this gap. Participants were 50 young adult women with any history of contraceptive use (including LARC) in Dane County, Wisconsin. Women often described providers as a trusted source of contraceptive information. However, several women reported that their preferences regarding contraceptive selection or removal were not honored. Furthermore, many participants believed that providers recommend LARC disproportionately to socially marginalized women. We encourage contraceptive counseling and removal protocols that directly address historical reproductive injustices and that honor patients’ wishes. PMID:27631741

  5. Long-acting opioid-agonists in the treatment of heroin addiction: why should we call them "substitution"?

    PubMed

    Gerra, G; Maremmani, I; Capovani, B; Somaini, L; Berterame, S; Tomas-Rossello, J; Saenz, E; Busse, A; Kleber, H

    2009-01-01

    Many studies have documented the safety, efficacy, and effectiveness of long-acting opioids (L-AOs), such as methadone and buprenorphine, in the treatment of heroin addiction. This article reviews the pharmacological differences between L-AO medications and short-acting opioids (heroin) in terms of reinforcing properties, pharmacokinetics, effects on the endocrine and immune systems. Given their specific pharmacological profile, L-AOs contribute to control addictive behavior, reduce craving, and restore the balance of disrupted endocrine function. The use of the term "substitution," referring to the fact that methadone or buprenorphine replace heroin in binding to brain opioid receptors, has been generalized to consider L-AOs as simple replacement of street drugs, thus contributing to the widespread misunderstanding of this treatment approach.

  6. Clozapine and long-acting injectable antipsychotic combination: A retrospective one-year mirror-image study.

    PubMed

    Souaiby, Lama; Gauthier, Claire; Rieu, Christine; Krebs, Marie-Odile; Advenier-Iakovlev, Emmanuelle; Gaillard, Raphaël

    2017-01-27

    To evaluate efficacy and tolerability of the combination of clozapine with an antipsychotic long-acting injectable (LAI) in multi-episode patients with schizophrenia or schizoaffective disorder. Efficacy and tolerability were assessed in seventeen patients admitted to a hospital in Paris between January 2010 and June 2015, using a one-year mirror-image design. Number and length of hospitalizations significantly decreased after introducing the combination (2.1 vs 0.8, p=0.004 and 155.4days vs 26.6days, p<0.001 respectively). No major adverse events occurred in terms of increased weight, agranulocytosis, hyperglycemia and/or dyslipidemia. This combination can be beneficial and safe in multi-episode patients.

  7. Paliperidone Palmitate Long-Acting Injectable Given Intramuscularly in the Deltoid Versus the Gluteal Muscle: Are They Therapeutically Equivalent?

    PubMed

    Yin, John; Collier, Abby C; Barr, Alasdair M; Honer, William G; Procyshyn, Ric M

    2015-08-01

    Paliperidone palmitate long-acting injectable is a second-generation antipsychotic indicated for the treatment of schizophrenia. According to the product monograph, the monthly maintenance dose of paliperidone palmitate can be given in either the deltoid or gluteal muscle. Unfortunately, many clinicians may misinterpret these directions to mean that these intramuscular sites are interchangeable, and thus therapeutically equivalent. Currently, the literature on this topic is sparse, but the published pharmacokinetic studies and Food and Drug Administration submission data on paliperidone palmitate show discrepancies in the elimination half-life, peak plasma concentration, and absorption rate that are dependent on the site of injection. The degree of shifts in pharmacokinetic parameters suggests that paliperidone palmitate injections via the deltoid and gluteal muscle are not bioequivalent and therefore are not therapeutically equivalent. Thus, using the same maintenance dosing regimen at both sites or switching between sites of injection may result in unforeseen consequences in patient outcomes.

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

    PubMed

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

    2016-12-14

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

  9. Development of sulfadiazine-decorated PLGA nanoparticles loaded with 5-fluorouracil and cell viability.

    PubMed

    Guimarães, Pedro Pires Goulart; Oliveira, Sheila Rodrigues; de Castro Rodrigues, Gabrielle; Gontijo, Savio Morato Lacerda; Lula, Ivana Silva; Cortés, Maria Esperanza; Denadai, Ângelo Márcio Leite; Sinisterra, Rubén Dario

    2015-01-08

    The aim of this work was to synthesize sulfadiazine-poly(lactide-co-glycolide) (SUL-PLGA) nanoparticles (NPs) for the efficient delivery of 5-fluorouracil to cancer cells. The SUL-PLGA conjugation was assessed using FTIR, 1H-NMR, 13C-NMR, elemental analysis and TG and DTA analysis. The SUL-PLGA NPs were characterized using transmission and scanning electron microscopy and dynamic light scattering. Additionally, the zeta potential, drug content, and in vitro 5-FU release were evaluated. We found that for the SUL-PLGA NPs, Dh = 114.0 nm, ZP = -32.1 mV and the encapsulation efficiency was 49%. The 5-FU was released for up to 7 days from the NPs. Cytotoxicity evaluations of 5-FU-loaded NPs (5-FU-SUL-PLGA and 5-FU-PLGA) on two cancer cell lines (Caco-2, A431) and two normal cell lines (fibroblast, osteoblast) were compared. Higher cytotoxicity of 5-FU-SUL-PLGA NPs were found to both cancer cell lines when compared to normal cell lines, demonstrating that the presence of SUL could significantly enhance the cytotoxicity of the 5-FU-SUL-PLGA NPs when compared with 5-FU-PLGA NPs. Thus, the development of 5-FU-SUL-PLGA NPs to cancer cells is a promising strategy for the 5-FU antitumor formulation in the future.

  10. Effects of PLGA reinforcement methods on the mechanical property of carbonate apatite foam.

    PubMed

    Munar, Girlie M; Munar, Melvin L; Tsuru, Kanji; Ishikawa, Kunio

    2014-01-01

    The purpose of this study was to improve the mechanical property of brittle carbonate apatite (CO3Ap) foam aimed as bone substitute material by reinforcement with poly(DL-lactide-co-glycolide) (PLGA). The CO3Ap foam was reinforced with PLGA by immersion and vacuum infiltration methods. Compressive strength of CO3Ap foam (12.0±4.9 kPa) increased after PLGA reinforcement by immersion (187.6±57.6 kPa) or vacuum infiltration (407.0±111.4 kPa). Scanning electron microscopic (SEM) observation showed a gapless PLGA and CO3Ap foam interface and larger amount of PLGA inside the hollow space of the strut when vacuum infiltration method was employed. In contrast a gap was observed at the PLGA and CO3Ap foam interface and less amount of PLGA inside the hollow space of the strut when immersion method was employed. Strong PLGA-CO3Ap foam interface and larger amount of PLGA inside the hollow space of the strut is therefore the key to higher mechanical property obtained for CO3Ap foam when vacuum infiltration was employed for PLGA reinforcement.

  11. Preparation and properties of PLGA nanofiber membranes reinforced with cellulose nanocrystals.

    PubMed

    Mo, Yunfei; Guo, Rui; Liu, Jianghui; Lan, Yong; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2015-08-01

    Although extensively used in the fields of drug-carrier and tissue engineering, the biocompatibility and mechanical properties of polylactide-polyglycolide (PLGA) nanofiber membranes still limit their applications. The objective of this study was to improve their utility by introducing cellulose nanocrystals (CNCs) into PLGA nanofiber membranes. PLGA and PLGA/CNC composite nanofiber membranes were prepared via electrospinning, and the morphology and thermodynamic and mechanical properties of these nanofiber membranes were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The cytocompatibility and cellular responses of the nanofiber membranes were also studied by WST-1 assay, SEM, and confocal laser scanning microscopy (CLSM). Incorporation of CNCs (1, 3, 5, and 7 wt.%) increased the average fiber diameter of the prepared nanofiber membranes from 100 nm (neat PLGA) to ∼400 nm (PLGA/7 wt.% CNC) and improved the thermal stability of the nanofiber membranes. Among the PLGA/CNC composite nanofiber membranes, those loaded with 7 wt.% CNC nanofiber membranes had the best mechanical properties, which were similar to those of human skin. Cell culture results showed that the PLGA/CNC composite nanofiber membranes had better cytocompatibility and facilitated fibroblast adhesion, spreading, and proliferation compared with neat PLGA nanofiber membranes. These preliminary results suggest that PLGA/CNC composite nanofiber membranes are promising new materials for the field of skin tissue engineering.

  12. Long-acting Inhaled Bronchodilator and Risk of Vascular Events in Patients With Chronic Obstructive Pulmonary Disease in Taiwan Population.

    PubMed

    Tsai, Ming-Jun; Chen, Chung-Yu; Huang, Yaw-Bin; Chao, Hsiao-Chung; Yang, Chih-Jen; Lin, Pei-Jin; Tsai, Yi-Hung

    2015-12-01

    A combination of long-acting anticholinergic agents (LAACs) and long-acting β2-adrenergic receptor agonist (LABA) is effective in improving lung function in chronic obstructive pulmonary disease (COPD) compared with monotherapy. However, evidence on whether this combination increases the incidence of stroke or other cardiac events remains sparse. The objective of the present study was to investigate the incidence of stroke and other cardiovascular diseases in COPD patients treated with LAAC, LABA, or a combination of the 2.We conducted this population-based study using the Taiwan National Health Insurance Research Database (1997-2008), identifying COPD patients and their prescribed medication from the International Classification of Disease, Ninth Revision codes 490-492 or 496. A multivariate Cox proportional-hazards model was used to compare the risk of stroke and other cardiovascular diseases over the 11-year period after treatment with LAAC or LABA only or in combination.Of the 596 COPD patients (mean age 70 y), 196 were treated with LAAC, 318 with LABA, and 82 were treated with a combination. The overall incidence of stroke (8.53%) significantly increased in the combination group compared with LAAC (2.04%) or LABA (1.26%) only. In the Cox regression analysis, the adjusted hazard ratio over the 11-year survey period for stroke in patients treated with the combination compared with LABA only was 1.04 (95% confidence interval, 1.06-2.99) and for LAAC, it was 0.31 (95% confidence interval, 0.02-2.32).This cohort study using a large health insurance database showed that treating patients with COPD, with a combination of LAAC and LABA, may be associated with an increased hazard of stroke compared with treatment with either agent alone. We should be particularly cautious about comedication of LAAC and LABA in patients with COPD.

  13. Long-acting neuroleptics used in wildlife management do not impair thermoregulation or physical activity in goats (Capra hircus).

    PubMed

    Fick, Linda; Mitchell, Duncan; Fuller, Andrea

    2007-06-01

    Long-acting neuroleptics commonly are used in wildlife management to decrease stress-related mortality in wild animals, but with possible effects on thermoregulation, which may contribute to residual morbidity and mortality. We investigated the effects of haloperidol (0.01, 0.1, 1 mg kg(-1), n=4), zuclopenthixol (0.1, 1, 10 mg kg(-1), n=4) and perphenazine (0.1, 1, 10 mg kg(-1), n=8), as well as control injections of sunflower oil, on body temperature and physical activity of laboratory goats under hot, cold and thermoneutral ambient temperatures. Implanted data loggers continuously recorded abdominal temperature, and data loggers attached externally on the foreleg recorded movement of unrestrained goats, in a climatic chamber at 35 degrees C, 10 degrees C and 22 degrees C. Cycling ambient temperature between 35 degrees C in daytime and 10 degrees C at night time caused a significant increase in amplitude of the circadian rhythm of body temperature in goats given sunflower oil (P=0.0012, unpaired t-test, n=8), but the administration of zuclopenthixol or perphenazine did not affect this change in amplitude (P>0.05, two-way ANOVA, n=4). Mean daily body temperature after administration of zuclopenthixol or perphenazine, and mean daily activity after zuclopenthixol administration, were not significantly different to those after control injections, at any ambient temperature, for the expected duration of drug activity (all P>0.05, two-way ANOVA, n=4). Thermal response indices, and mean activity, during heat, cold or thermoneutral exposure, of goats for 7 h after haloperidol injection, were not significantly different, at any dose or any ambient temperature, to those following control injections (all P>0.05, repeated measures ANOVA, n=4). Long-acting neuroleptics did not impair activity or thermoregulation of goats subjected to inescapable thermal challenges.

  14. Comparative pharmacokinetics of a new oral long-acting formulation of doxycycline hyclate: A canine clinical trial.

    PubMed

    Arciniegas Ruiz, Sara Melisa; Gutiérrez Olvera, Lilia; Bernad Bernad, María Josefa; Caballero Chacón, Sara Del Carmen; Vargas Estrada, Dinorah

    2015-12-01

    Doxycicline is used in dogs as treatment of several bacterial infections, mycoplasma, chlamydia and rickettsial diseases. However, it requires long treatments and several doses to be effective. The aim of this study was to determine the pharmacokinetics of four formulations of doxycycline hyclate, administered orally, with different proportions of excipients, acrylic acid-polymethacrylate-based matrices, to obtain longer therapeutic levels than conventional formulation. Forty-eight dogs were randomly assigned in five groups to receive a single oral dose (20mg/kg) of doxycycline hyclate without excipients (control) or a long-acting formulation containing doxycycline, acrylic acid polymer, and polymethacrylate in one of the following four proportions: DOX1(1:0.25:0.0035), DOX2(1:0.5:0.0075), DOX3 (1:1:0.015), or DOX4(1:2:0.0225). Temporal profiles of serum concentrations were obtained at several intervals after each treatment. Therapeutic concentrations were observed for 60h for DOX1 and DOX4, 48h for DOX2 and DOX3 and only 24h for DOX-C. None of the pharmacokinetic parameter differed significantly between DOX1 and DOX2 or between DOX3 and DOX4; however, the findings for the control treatment were significantly different compared to all four long-acting formulations. Results indicated that DOX1 had the most adequate pharmacokinetic-pharmacodynamic relationships for a time-dependent drug and had longer release times than did doxycycline alone. However, all four formulations can be effective depend on the minimum effective serum doxycycline concentration of the microorganism being treated. These results suggest that the use of any of these formulations can reduce the frequency of administration, the patient's stress, occurrence of adverse effects and the cost of treatment.

  15. Premorbid functioning and treatment response in recent-onset schizophrenia: prospective study with risperidone long-acting injectable.

    PubMed

    Rabinowitz, Jonathan; Napryeyenko, Oleksandr; Burba, Benjaminas; Martinez, Guadalupe; Neznanov, Nikolay G; Fischel, Tsvi; Baylé, Franck J; Cavallaro, Roberto; Smeraldi, Enrico; Schreiner, Andreas

    2011-02-01

    Premorbid functioning may be associated with treatment response, but this is confounded by a lack of prospective longitudinal data and controls for medication compliance. This study tested the hypothesis that good premorbid functioning will be associated with better antipsychotic treatment response after controlling for drug adherence by using a long-acting injectable antipsychotic. This was a 6-month, open label, multicenter, phase IV trial in recent-onset schizophrenia treated with flexible doses of risperidone long-acting injectable (25-50 mg every 14 days). Premorbid functioning was assessed with the Premorbid Adjustment Scale (PAS)-Structured Interview; efficacy was evaluated with clinician-rated Positive and Negative Syndrome Scale, Clinical Global Impression scale of Severity of Illness, Clinical Global Impression scale of Change, Global Assessment of Functioning Scale, and trial participant completed SF-36. Analyses controlled for baseline scores and demographics. With the use of a priori PAS scoring criteria, the participants' premorbid functioning was categorized as stable-good (n = 142), stable-poor (n = 116), and deteriorating (n = 36). At baseline, the stable-good group had the best functioning on most efficacy measures. All groups showed significant improvement on efficacy measures with treatment. Improvement was significantly higher for the stable-good group. The PAS global assessment of highest level of functioning scale (excellent, n = 75; good, n = 117; fair, n = 78; and poor, n = 31) showed a strong association with baseline functioning and improvement and had a significant linear association with meeting Remission in Schizophrenia Working Group symptom criteria at baseline (P = 0.003) and attained and sustained remission for 3 months during study (47.7%, 49.3%, 29.6%, and 22.2%; P = 0.006). Good premorbid functioning corresponds with better treatment response in recent-onset psychosis as captured on both clinician and patient-reported measures.

  16. Microspheres and nanoparticles from ultrasound

    NASA Astrophysics Data System (ADS)

    Suh, Won Hyuk

    Improved preparations of various examples of monodispersed, porous, hollow, and core-shell metal and semiconductor nanoparticles or nanowires have been developed. Now titania microspheres and nanoparticles and silica microspheres can be synthesized using an inexpensive high frequency (1.7 MHz) ultrasonic generator (household humidifier; ultrasonic spray pyrolysis; USP). Morphology and pore size of titania microspheres were controlled by the silica to Ti(IV) ratio and silica particle size. Fine tuning the precursor ratio affords sub-50 nm titania nanoparticles as well. In terms of silica microspheres, morphology was controlled by the silica to organic monomer ratio. In liquids irradiated with high intensity ultrasound (20 kHz; HIUS), acoustic cavitation produces high energy chemistry through intense local heating inside the gas phase of collapsing bubbles in the liquid. HIUS and USP confine the chemical reactions to isolated sub-micron reaction zones, but sonochemistry does so in a heated gas phase within a liquid, while USP uses a hot liquid droplet carried by a gas flow. Thus, USP can be viewed as a method of phase-separated synthesis using submicron-sized droplets as isolated chemical reactors for nanomaterial synthesis. While USP has been used to create both titania and silica spheres separately, there are no prior reports of titania-silica composites. Such nanocomposites of metal oxides have been produced, and by further manipulation, various porous structures with fascinating morphologies were generated. Briefly, a precursor solution was nebulized using a commercially available household ultrasonic humidifier (1.7 MHz ultrasound generator), and the resulting mist was carried in a gas stream of air through a quartz glass tube in a hot furnace. After exiting the hot zone, these microspheres are porous or hollow and in certain cases magnetically responsive. In the case of titania microspheres, they are rapidly taken up into the cytoplasm of mammalian cells and

  17. Fabrication of Fucoxanthin-Loaded Microsphere(F-LM) By Two Steps Double-Emulsion Solvent Evaporation Method and Characterization of Fucoxanthin before and after Microencapsulation.

    PubMed

    Noviendri, Dedi; Jaswir, Irwandi; Taher, Muhammad; Mohamed, Farahidah; Salleh, Hamzah Mohd; Noorbatcha, Ibrahim Ali; Octavianti, Fitri; Lestari, Widya; Hendri, Ridar; Ahmad, Hasna; Miyashita, Kazuo; Abdullah, Alias

    2016-08-01

    Microencapsulation is a promising approach in drug delivery to protect the drug from degradation and allow controlled release of the drug in the body. Fucoxanthin-loaded microsphere (F-LM) was fabricated by two step w/o/w double emulsion solvent evaporation method with poly (L-lactic-coglycolic acid) (PLGA) as carrier. The effect of four types of surfactants (PVA, Tween-20, Span-20 and SDS), homogenization speed, and concentration of PLGA polymer and surfactant (PVA), respectively, on particle size and morphology of F-LM were investigated. Among the surfactants tested, PVA showed the best results with smallest particle size (9.18 µm) and a smooth spherical surface. Increasing the homogenization speed resulted in a smaller mean F-LM particle size [d(0.50)] from 17.12 to 9.18 µm. Best particle size results and good morphology were attained at homogenization speed of 20 500 rpm. Meanwhile, increased PLGA concentration from 1.5 to 11.0 (% w/v) resulted in increased F-LM particle size. The mean particle size [d(0.5)] of F-LM increased from 3.93 to 11.88 µm. At 6.0 (% w/v) PLGA, F-LM showed the best structure and external morphology. Finally, increasing PVA concentration from 0.5 to 3.5 (% w/v) resulted in decreased particle size from 9.18 to 4.86 µm. Fucoxanthin characterization before and after microencapsulation was carried out to assess the success of the microencapsulation procedure. Thermo gravimetry analysis (TGA), glass transition (Tg) temperature of F-LM and fucoxanthin measured using DSC, ATR-FTIR and XRD indicated that fucoxanthin was successfully encapsulated into the PLGA matrix, while maintaining the structural and chemical integrity of fucoxanthin.

  18. Muscle regeneration by adipose tissue-derived adult stem cells attached to injectable PLGA spheres.

    PubMed

    Kim, MiJung; Choi, Yu Suk; Yang, Seung Hye; Hong, Hea-Nam; Cho, Sung-Woo; Cha, Sang Myun; Pak, Jhang Ho; Kim, Chan Wha; Kwon, Seog Woon; Park, Chan Jeoung

    2006-09-22

    The [corrected] use of adult stem cells for cell-based tissue engineering and regeneration strategies represents a promising approach for skeletal muscle repair. We have evaluated the combination of adipose tissue-derived adult stem cells (ADSCs) obtained from autologous liposuction and injectable poly(lactic-co-glycolic acid) (PLGA) spheres for muscle regeneration. ADSCs attached to PLGA spheres and PLGA spheres alone were cultured in myogenic medium for 21 days and injected subcutaneously into the necks of nude mice. After 30 and 60 days, the mice were sacrificed, and newly formed tissues were analyzed by immunostaining, H and E staining, and RT-PCR. We found that ADSCs attached to PLGA spheres, but not PLGA spheres alone, were able to generate muscle tissue. These findings suggest that ADSCs and PLGA spheres are useful materials for muscle tissue engineering and that their combination can be used in clinical settings for muscle regeneration.

  19. Fabrication of functional PLGA-based electrospun scaffolds and their applications in biomedical engineering.

    PubMed

    Zhao, Wen; Li, Jiaojiao; Jin, Kaixiang; Liu, Wenlong; Qiu, Xuefeng; Li, Chenrui

    2016-02-01

    Electrospun PLGA-based scaffolds have been applied extensively in biomedical engineering, such as tissue engineering and drug delivery system. Due to lack of the recognition sites on cells, hydropholicity and single-function, the applications of PLGA fibrous scaffolds are limited. In order to tackle these issues, many works have been done to obtain functional PLGA-based scaffolds, including surface modifications, the fabrication of PLGA-based composite scaffolds and drug-loaded scaffolds. The functional PLGA-based scaffolds have significantly improved cell adhesion, attachment and proliferation. Moreover, the current study has summarized the applications of functional PLGA-based scaffolds in wound dressing, vascular and bone tissue engineering area as well as drug delivery system.

  20. Magnetoresponsive Photonic Microspheres with Structural Color Gradient.

    PubMed

    Lee, Seung Yeol; Choi, Jongkook; Jeong, Jong-Ryul; Shin, Jung H; Kim, Shin-Hyun

    2017-02-06

    Photonic Janus particles are created by alternately sputtering silica and titania on microspheres in order to obtain a structural color gradient. In addition, the microspheres are rendered magnetoresponsive. The Janus microspheres with optical and magnetic anisotropy enable on-demand control over orientation and structural color through manipulation of an external magnetic field, thereby being useful as active color pigments for reflection-mode displays.

  1. Filling Porous Microspheres With Magnetic Material

    NASA Technical Reports Server (NTRS)

    Chang, Manchium; Colvin, Michael S.

    1990-01-01

    New process produces magnetic microspheres with controllable sizes, compositions, and properties for use in medical diagnostic tests, biological research, and chemical processes. Paramagnetic microspheres also made with process. Porous plastic microspheres prepared by polymerization of monomer in diluent by cross-linking agent. When diluent removed, it leaves tiny pores throughout polymerized spheres. Size and distribution of pores determined by amount and type of diluent and cross-linking agent.

  2. Microsphere coated substrate containing reactive aldehyde groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1984-01-01

    A synthetic organic resin is coated with a continuous layer of contiguous, tangential, individual microspheres having a uniform diameter preferably between 100 Angstroms and 2000 Angstroms. The microspheres are an addition polymerized polymer of an unsaturated aldehyde containing 4 to 20 carbon atoms and are covalently bonded to the substrate by means of high energy radiation grafting. The microspheres contain reactive aldehyde groups and can form conjugates with proteins such as enzymes or other aldehyde reactive materials.

  3. Glass microspheres for medical applications

    NASA Astrophysics Data System (ADS)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in <1 week, without causing any detectable joint damage. The combination of dysprosium lithium borate glass microspheres and EDTA chelation therapy provides an unique "tool" for the medical community, which can deliver a large dose (>100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass

  4. Effects of chemical and physical parameters in the generation of microspheres by hydrodynamic flow focusing.

    PubMed

    Schneider, Thomas; Chapman, Glenn H; Häfeli, Urs O

    2011-10-15

    Hydrodynamic flow focusing is a seminal, easy-to-use technology for micro- and nanodroplet generation. It is characterized by the co-axial focusing of two (or more) immiscible liquid streams forced through a small orifice. In this method, the outer continuous phase has a much higher flow velocity than the inner disperse phase. While passing through the orifice, the prevailing pressure drop and shear stress force the inner phase to break up into uniform droplets. Using a biodegradable poly(lactide-co-glycolide) (PLGA) polymer solution as the disperse phase, monodisperse and user-defined polymer micro- and nanospheres can be generated. Here we present a consecutive parameter study of hydrodynamic flow focusing to study the effect of chemical and physical parameters that effect the dispersity of the droplets generated in the 1-5 μm range. The parameter study shows the applicability and challenges of hydrodynamic flow focusing in the preparation of biodegradable microspheres. Applications for microspheres made with this method can be found in the medical, pharmaceutical and technical fields.

  5. Formulations for modulation of protein release from large-size PLGA microparticles for tissue engineering.

    PubMed

    Qodratnama, Roozbeh; Serino, Lorenzo Pio; Cox, Helen C; Qutachi, Omar; White, Lisa J

    2015-02-01

    In this study we present an approach to pre-program lysozyme release from large size (100-300 μm) poly(DL-lactic acid-co-glycolic acid) (PLGA) microparticles. This approach involved blending in-house synthesized triblock copolymers with a PLGA 85:15. In this work it is demonstrated that the lysozyme release rate and the total release are related to the mass of triblock copolymer present in polymer formulation. Two triblock copolymers (PLGA-PEG1500-PLGA and PLGA-PEG1000-PLGA) were synthesized and used in this study. In a like-for-like comparison, these two triblock copolymers appeared to have similar effects on the release of lysozyme. It was shown that blending resulted in the increase of the total lysozyme release and shortened the release period (70% release within 30 days). These results demonstrated that blending PLGA-PEG-PLGA triblock copolymer with PLGA 85:15 can be used as a method to pre-program protein release from microparticles. These microparticles with modulated protein release properties may be used to create microparticle-based tissue engineering constructs with pre-programmed release properties.

  6. PLGA Nanoparticles as Subconjunctival Injection for Management of Glaucoma.

    PubMed

    Salama, Hamed A; Ghorab, Mahmoud; Mahmoud, Azza A; Abdel Hady, Mayssa

    2017-02-21

    Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), could be a promising system for targeting ocular drug delivery. The objective of this work was to investigate the possibility of encapsulating brinzolamide in PLGA nanoparticles in order to be applied as a subconjunctival injection that could represent a starting point for developing new therapeutic strategies against increase in ocular pressure. The brinzolamide-loaded PLGA nanoparticles were fabricated using emulsion-diffusion-evaporation method with varying concentrations of Tween 80 or poloxamer 188 (Plx) in aqueous and organic phases. The nanoparticles were characterized in terms of particle size and size distribution, entrapment efficiency and in-vitro drug release pattern as well as DSC and X-ray analysis. Nanoparticles prepared using Tween 80 in the aqueous phase showed higher encapsulation efficiency and smaller particle size-values compared to those prepared using Plx. Furthermore, the addition of Plx 188 or Brij 97 to the organic phase in the formulation containing Tween 80 in the aqueous phase led to an increase in the particle diameter-values of the obtained nanoparticles. The nanoparticles had the capacity to release the brinzolamide in a biphasic release profile. The nanoparticles were spherical in shape and the drug was entraped in the nanoparticles in an amorphous form. Selected nanoparticles, injected subconjunctivally in normotensive Albino rabbits, were able to reduce the IOP for up to 10 days. Nanoparticles loaded with brinzolamide with lower particle size were able to reduce the IOP for longer period compared to those with higher particle size. Histopathological studies for the anterior cross sections of the rabbits' eyes revealed that the tested nanoparticles were compatible with the ocular tissue. The overall results support that PLGA nanoparticles, applied as subconjunctival injection, can be considered as a promising carrier for

  7. Switching to olanzapine long-acting injection from either oral olanzapine or any other antipsychotic: comparative post hoc analyses

    PubMed Central

    Ciudad, Antonio; Anand, Ernie; Berggren, Lovisa; Casillas, Marta; Schacht, Alexander; Perrin, Elena

    2013-01-01

    Background A considerable proportion of patients suffering from schizophrenia show suboptimal responses to oral antipsychotics due to inadequate adherence. Hence, they are likely to benefit from switching to a long-acting injectable formulation. These post hoc analyses assessed the clinical effects of switching to olanzapine long-acting injection (OLAI) from either oral olanzapine (OLZ) or other antipsychotics (non-OLZ). Methods Post hoc analyses were done based on two randomized studies (one short-term, one long-term) conducted in patients suffering from schizophrenia and treated with OLAI. The short-term study was an 8-week placebo-controlled, double-blind trial in acute patients, and the long-term study was a 2-year, oral olanzapine-controlled, open-label, follow-up of stabilized outpatients. Results These analyses used data from 62 OLAI-treated patients (12 switched from OLZ, 50 from non-OLZ) from the short-term study and 190 OLAI-treated patients (56 switched from OLZ, 134 from non-OLZ) from the long-term study. Kaplan–Meier survival analyses of time to all-cause discontinuation of OLAI treatment did not differ significantly between OLZ and non-OLZ patients in the short-term study (P=0.209) or long-term study (P=0.448). Similarly, the proportions of OLZ and non-OLZ patients that discontinued OLAI were not statistically different in the short-term (16.7% versus 36.0%, respectively; P=0.198) or long-term (57.1% versus 47.8% respectively; P=0.238) studies. In the short-term study, no significant differences were detected between the patient groups in mean change in Positive and Negative Syndrome Scale (PANSS) total score (−13.4 OLZ versus −20.8 non-OLZ; P=0.166). In the long-term study, mean change in PANSS total score (3.9 OLZ versus −3.6 non-OLZ; P=0.008) was significantly different between the non-OLZ and OLZ groups. Rates of treatment-emergent adverse events were similar in OLZ and non-OLZ groups per study. Conclusion These post hoc analyses suggest

  8. Worsening of myasthenia gravis after administration of injectable long-acting risperidone for treatment of schizophrenia; first case report and a call for caution.

    PubMed

    Al-Hashel, Jasem Y; Ismail, Ismail Ibrahim; John, John K; Ibrahim, Mohammed; Ali, Mahmoud

    2016-01-01

    Myasthenia gravis is an autoimmune disease characterized by muscle weakness due to autoantibodies affecting the neuromuscular junction. Co-occurrence of myasthenia gravis and schizophrenia is very rare and raises a challenge in management of both diseases. Antipsychotic drugs exhibit anticholinergic side effects and have the potentials of worsening myasthenia. Long-acting risperidone is an injectable atypical antipsychotic drug that has not been previously reported to worsen myasthenia gravis in literature. We report the first case report of worsening of myasthenia after receiving long-acting risperidone injection for schizophrenia in a 29-year-old female with both diseases. She started to have worsening 2 weeks following the first injection and her symptoms persisted despite receiving plasma exchange. This could be explained by the pharmacokinetics of the drug. We recommend that long-acting risperidone should be used with caution in patients with myasthenia gravis, and clinicians must be aware of the potential risks of this therapy.

  9. Surface modification of PLGA nanoparticles with biotinylated chitosan for the sustained in vitro release and the enhanced cytotoxicity of epirubicin.

    PubMed

    Chen, Hongli; Xie, Li Qin; Qin, Jingwen; Jia, Yajing; Cai, Xinhua; Nan, WenBin; Yang, Wancai; Lv, Feng; Zhang, Qi Qing

    2016-02-01

    In this study, poly(d,l-lactide-co-glycolide) nanoparticles (PLGA NPs) with biotinylated chitosan (Bio-CS)-surface modification were prepared to be usded as a tumor-targeted and prolonged delivery system for anticancer drugs. Epirubicin (EPB), as a model drug, was encapsulated into Bio-CS surface modified PLGA (Bio-CS-PLGA) NPs with a drug encapsulation efficiency of 84.1 ± 3.4%. EPB-loaded Bio-CS-PLGA NPs were spherical shaped, and had a larger size and higher positive zeta potential compared to the unmodfied EPB-loaded PLGA NPs. The in vitro drug releases showed that EPB-loaded Bio-CS-PLGA NPs exhibited relatively constant drug release kinetics during the first 48 h and the drug burst release significantly decreased in comparison to the unmodified PLGA NPs. The results of MTS assays showed that Bio-CS-PLGA NPs markedly increased the cytotoxicity of EPB, compared to both the unmodified PLGA NPs and the CS-PLGA NPs. The uptakes of NPs in human breast cancer MCF-7 cells were evaluated by the flow cytometry and the confocal microscope. The results revealed that Bio-CS-PLGA NPs exhibited a greater extent of cellular uptake than the unmodified PLGA NPs and CS-PLGA NPs. Moreover, the cellular uptake of Bio-CS-PLGA NPs was evidently inhibited by the endocytic inhibitors and the receptor ligand, indicating that biotin receptor-mediated endocytosis was perhaps involved in the cell entry of Bio-CS-PLGA NPs. In MCF-7 tumor-bearing nude mice, EPB-loaded Bio-CS-PLGA NPs were efficiently accumulated in the tumors. In summary, Bio-CS-PLGA NPs displayed great potential for application as the carriers of anticancer drugs.

  10. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, Richard W.; Hrubesh, Lawrence W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  11. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  12. HDL-Mimetic PLGA Nanoparticle To Target Atherosclerosis Plaque Macrophages

    PubMed Central

    Sanchez-Gaytan, Brenda L.; Fay, Francois; Lobatto, Mark E.; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E. M.; van Rijs, Sarian M.; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J.; Langer, Robert; Fayad, Zahi A.; Mulder, Willem J M

    2015-01-01

    High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA–HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA–HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers. PMID:25650634

  13. Microspheres in Plasma Display Panels

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Filling small bubbles of molten glass with gases is just as difficult as it sounds, but the technical staff at NASA is not known to shy away from a difficult task. When Microsphere Systems, Inc. (MSI), of Ypsilanti, Michigan, and Imaging Systems Technology, Inc. (IST), of Toledo, Ohio, were trying to push the limits of plasma displays but were having difficulty with the designs, NASA s Glenn Garrett Morgan Commercialization Initiative (GMCI) assembled key personnel at Glenn Research Center and Ohio State University for a brainstorming session to come up with a solution for the companies. They needed a system that could produce hollow, glass micro-sized spheres (microspheres) that could be filled with a variety of gasses. But the extremely high temperature required to force the micro-sized glass bubbles to form at the tip of a metal nozzle resulted in severe discoloration of the microspheres. After countless experiments on various glass-metal combinations, they had turned to the GMCI for help. NASA experts in advanced metals, ceramics, and glass concluded that a new design approach was necessary. The team determined that what was needed was a phosphate glass composition that would remain transparent, and they went to work on a solution. Six weeks later, using the design tips from the NASA team, Tim Henderson, president of MSI, had designed a new system in which all surfaces in contact with the molten glass would be ceramic instead of metal. Meanwhile, IST was able to complete a Phase I Small Business Innovation Research (SBIR) grant supported by the National Science Foundation (NSF) and supply a potential customer with samples of the microspheres for evaluation as filler materials for high-performance insulations.

  14. Nonaggregating Microspheres Containing Aldehyde Groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan

    1989-01-01

    Cobalt gamma irradiation of hydrophilic monomers in presence of acrolein yields exceptionally-stable, nonaggregating microspheres. Mixtures of 2-hydroxyethyl methacrylate (HEMA) and acrolein form homogeneous solutions in distilled water containing 0.4 percent polyethylene oxide (PEO). After deaeration with nitrogen, mixtures irradiated at room temperature with gamma rays from cobalt source; total exposure time 4 hours, at rate of 0.2 milliroentgen per hour. Reaction product centrifuged three times for purification and kept in distilled water.

  15. Making Latex Microspheres in Space

    NASA Technical Reports Server (NTRS)

    Kornfeld, D. M.; Vanderhoff, J. W.; El-Aasser, M. S.; Micale, F. J.; Sudol, E. D.; Tseng, C. M.; Silwanowicz, A.

    1986-01-01

    Equipment yields larger, more uniform particles. Two NASA reports describe first commercial product to be manufactured in space. Product monodisperse latex, suspension of spherical particles of essentially same diameter. Carried aboard Space Shuttle on its orbital missions, monodisperse latex reactor (MLR) produces spheres of much larger size than possible on Earth. Mircospheres 30 micrometers in diameter produced, whereas 5 micrometers is limit for Earthbound reactors. Microspheres as large as 100 micrometers scheduled for production in MLR.

  16. Pharmacokinetics and milk penetration of difloxacin after a long-acting formulation for subcutaneous administration to lactating goats.

    PubMed

    Marín, P; Escudero, E; Fernández-Varón, E; Ramírez, M J; Cárceles, C M

    2010-07-01

    The single-dose disposition kinetics of difloxacin were determined in clinically normal lactating goats (n=6) after intravenous (IV) and subcutaneous (SC) administration and subcutaneous administration of a long-acting poloxamer 407 gel formulation (P407). Difloxacin concentrations were determined by HPLC with fluorescence detection. Minimum inhibitory concentrations of difloxacin against 14 strains of Staphylococcus aureus isolated from mastitic goats' milk in Spain were determined to compute pharmacodynamic surrogate markers. The concentration-time data were analyzed by compartmental and noncompartmental pharmacokinetic methods. Following SC and P407 administration, difloxacin achieved maximum milk concentrations of 1.34+/-0.12 and 2.97+/-1.18 mg/L, respectively, at 4.00+/-0.00 h (SC) and 3.60+/-0.89 h (P407) after administration. The absolute bioavailabilities after SC and P407 administration were 81.74+/-15.60% and 72.58+/-20.45%, respectively. Difloxacin penetration from the blood into the milk was good and high concentrations were found in milk secretions. From these data, a 15 mg/kg dose of difloxacin P407 would appear to be effective against Staphylococcus aureus isolated from mastitic goats' milk with minimum inhibitory concentrations

  17. Pharmacokinetics of moxifloxacin in rabbits after intravenous, subcutaneous and a long-acting poloxamer 407 gel formulation administration.

    PubMed

    Cárceles, C M; Serrano, J M; Marín, P; Escudero, E; Fernández-Varón, E

    2006-08-01

    The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long-acting poloxamer 407 gel formulation (SC-P407). Moxifloxacin concentrations were determined by high-performance liquid chromatography assay with fluorescence detection. Mean half-life for IV, SC and SC-P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the C(max) was 1.61 +/- 0.49 mg/l. After SC-P407 administration, the bioavailability was 44% and the C(max) 1.83 was +/-0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC-P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC-P407 formulation and the favourable PK behaviour such as the long half-life, acceptable bioavailability and excellent PK-PD ratios achieved indicate that it is likely to be effective in rabbits.

  18. Pharmacokinetic and milk penetration of a difloxacin long-acting poloxamer gel formulation with carboxy-methylcellulose in lactating goats.

    PubMed

    Escudero, Elisa; Marín, Pedro; Cárceles, Carlos M; Ramírez, María J; Fernández-Varón, Emilio

    2011-04-01

    The single-dose disposition kinetics of difloxacin were determined in clinically normal lactating goats (n=6) after subcutaneous administration of a long-acting poloxamer 407 gel formulation with carboxy-methylcellulose (P407-CMC). Difloxacin concentrations were determined by high performance liquid chromatography with fluorescence detection. The concentration-time data were analysed by non-compartmental kinetic methods. Plasma and milk elimination half-lives after P407-CMC dosing were 35.19 h and 33.93 h, respectively. With this formulation, difloxacin achieved maximum plasma concentrations of 2.67±0.34 mg/L at 2.92±1.20 h and maximum milk concentrations of 2.31±0.35 mg/L at 4.00±0.00 h. The area under the curve (AUC) ratio AUC(milk)/AUC(plasma) was 0.89 after P407-CMC administration. It was concluded that a 15 mg/kg dose of difloxacin within P407-CMC would be effective against mastitis pathogens with a minimum inhibitory concentration (MIC)≤0.12 mg/L.

  19. Oily nanosuspension for long-acting intramuscular delivery of curcumin didecanoate prodrug: preparation, characterization and in vivo evaluation.

    PubMed

    Wei, Xiao-Lan; Han, Ying-Rui; Quan, Li-Hui; Liu, Chun-Yu; Liao, Yong-Hong

    2013-05-13

    The objective of this study was to prepare the nanocrystals of curcumin didecanoate (CurDD) by wet ball milling and to investigate the comparative pharmacokinetics of oily nano- and micro-suspensions after intramuscular (i.m.) administration to rats. Upon optimizing the wet ball milling parameters, CurDD nanocrystals were produced with median particle size of ~500 nm and the freeze-dried nanocrystals were readily dispersed in peanut oil to form stable nanosuspensions. Although the nanosuspension appeared to exhibit slower clearance from the injection site after i.m. injection, compared to microsuspension (~5 μm), a significantly higher maximum plasma curcumin concentration (69.0 ng/ml) was observed for the former than that for the latter (18.5 ng/ml). In addition, the nanosuspension provided significant higher plasma curcumin concentrations and brain CurDD contents for at least 15 days than the microsuspension, except for the initial times. A single i.m. injection of nanosuspension appeared to achieve reversal effect on reserpine-induced hypothermia for at least 13 days. This study demonstrates that CurDD nanosuspension may act as a long-acting i.m. injectable for sustained delivery of curcumin, potentially applicable to elicit a long-lasting antidepressant effect.

  20. Chemoimmunoprophylaxis against bovine tropical theileriosis in young calves: a comparison between buparvaquone and long-acting oxytetracycline.

    PubMed

    Dhar, S; Malhotra, D V; Bhushan, C; Gautam, O P

    1990-07-01

    Eighteen seven to 21-day-old crossbred (Bos taurus cross Bos indicus) calves were allocated to four groups (A to D). Groups A and B each consisted of six calves and groups C and D three calves each. Each calf in groups A, B and C was inoculated with ground-up tick supernate (GUTS) equivalent to two infected acini prepared from Theileria annulata-infected Hyalomma anatolicum anatolicum. Each calf in group A was also given a single intramuscular injection of buparvaquone, 2.5 mg kg-1 bodyweight simultaneously with GUTS, whereas each calf in group B was given a single intramuscular injection of long-acting oxytetracycline, 20 mg kg-1 bodyweight following inoculation of GUTS. In calves of group A clinicopathological reactions were negligible, whereas in calves of group B mild to severe reactions were observed resulting in the death of three of the six calves. All the calves of group C (infected, untreated controls) died of acute theileriosis. All the surviving calves of groups A and B withstood a lethal homologous challenge given on day 30 after immunisation, indicating no difference in the immune status of the surviving calves of the two groups. Group D, challenge control, all calves died of theileriosis within 18 days of challenge.

  1. Insulin degludec, a long-acting once-daily basal analogue for type 1 and type 2 diabetes mellitus.

    PubMed

    Berard, Lori; MacNeill, Gail

    2015-02-01

    Here, we discuss certain practical issues related to use of insulin degludec, a new long-acting basal insulin analogue. Degludec provides uniform ("peakless") action that extends over more than 24 hours and is highly consistent from dose to dose. Like the 2 previously available basal analogues (detemir and glargine), degludec is expected to simplify dose adjustment and enable patients to reach their glycemic targets with reduced risk of hypoglycemia. Phase 3 clinical trials involving type 1 and type 2 diabetes have demonstrated that degludec was noninferior to glargine in allowing patients to reach a target glycated hemoglobin (A1C) of 7%, and nocturnal hypoglycemia occurred significantly less frequently with degludec. In addition, when dosing intervals vary substantially from day to day, degludec continues to be effective and to maintain a low rate of nocturnal hypoglycemia. Degludec thus has the potential to reduce risk of nocturnal hypoglycemia, to enhance the flexibility of the dosing schedule and to improve patient and caregiver confidence in the stability of glycemic control. A dedicated injector, the FlexTouch prefilled pen, containing degludec 200 units/mL, will be recommended for most patients with type 2 diabetes. Degludec will also be available as 100 units/mL cartridges, to be used in the NovoPen 4 by patients requiring smaller basal insulin doses, including most patients with type 1 diabetes.

  2. [Studies of time-course changes in human body balance after ingestion of long-acting hypnotics].

    PubMed

    Nakamura, Masahiro; Ishii, Masanori; Niwa, Yoji; Yamazaki, Momoko; Ito, Hiroshi

    2004-02-01

    Falling accidents are a serious nocosomial problem, with balance disorders after the ingestion of hypnotics said to be a cause. Based on the results of animal studies, it was postulated that this problem involves the muscle relaxation that is a pharmacological effect of benzodiazepines (BZP). No reports have, to our knowledge, been made of time-course changes in human body balance after ingestion of hypnotics. Accordingly, we used quazepam (Doral), a long-acting hypnotic considered to show comparatively weak muscle relaxation, to study static balance after drug ingestion in human volunteers. Briefly, informed consent was obtained from 8 healthy adults, then a gait analytic system (Gangas) was used to test static balance after drug ingestion (Mann and Romberg tests). We also measured circulating drug concentration over time. Our results showed that balance disorders occurred after quazepam ingestion with an unstable posture particularly striking. Given the function of quazepam receptors, it is difficult to surmise that balance disorders after drug ingestion were due to the drug's muscle relaxation. We surmised that inhibition from the central nervous system in connection with nerves awakening was involved. We found a strong correlation between the manifestation of balance disorders after drug ingestion and circulating drug concentration.

  3. PEGylated recombinant human interferon-ω as a long-acting antiviral agent: structure, antiviral activity and pharmacokinetics.

    PubMed

    Yu, Weili; Yu, Changming; Wu, Ling; Fang, Ting; Qiu, Rui; Zhang, Jinlong; Yu, Ting; Fu, Ling; Chen, Wei; Hu, Tao

    2014-08-01

    Recombinant human interferon-ω (rhIFN-ω) exhibits a potent antiviral activity. Because of poor pharmacokinetics (PK) of rhIFN-ω, frequent dosing of rhIFN-ω is necessitated to achieve the sustained antiviral efficacy. PEGylation can efficiently improve the PK of rhIFN-ω while substantially decrease its bioactivity. The structure, antiviral activity and PK of the PEGylated rhIFN-ω were measured to establish their relationship with PEGylation sites, polyethylene glycol (PEG) mass and PEG structure. Accordingly, N-terminus and the ly