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Drug Release Profiles (drug + release_profile)
Selected AbstractsDevelopment of a Controlled Release System for Risperidone Using Polypyrrole: Mechanistic StudiesELECTROANALYSIS, Issue 4 2010Darren Svirskis Abstract Polypyrrole (PPY) film has been selected as a platform material for drug delivery due to its inherent conductivity, ease of preparation and apparent biocompatibility. PPY films were prepared containing the antipsychotic drug risperidone as a model compound. Drug release profiles could be altered by applying different electrical stimulation to these films. Atomic force microscopy was used to investigate changes in PPY film thickness when different stimuli were applied. The highest levels of drug release were observed when PPY was reduced; this was accompanied by expansion of the film. Technology such as this could be utilized for implantable drug delivery devices, where the dose could be adjusted by external signaling. [source] Biomacromolecular engineering: design, synthesis and characterization.POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9-10 2006One-pot synthesis of block copolymers of arborescent polyisobutylene, polystyrene Abstract Novel arborescent block copolymers comprising of an arborescent rubbery polyisobutylene (PIB) midsegment and glassy polystyrene (PSt) end blocks were prepared by sequential addition of monomers. Synthesis was conducted by the use of 4-(2-methoxyisopropyl) styrene as an inimer-type initiator in conjunction with titanium tetrachloride (TiCl4) in 60:40 (v/v) methylcyclohexane/methyl chloride solvent mixture. Isobutylene was polymerized for 1,2,hr and then prechilled styrene in the same solvent mixture was sequentially added with select additives to the reaction flask. The recovered block copolymers were purified and then characterized by 1H-NMR, size exclusion chromatograph (SEC), tensile test, atomic force Microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Samples with 16.4,32.8,wt% PSt and Mn,=,47,600,125,900,g/mol (Mw/Mn,=,2.02,4.45) displayed thermoplastic elastomeric properties with 5,9.2,MPa tensile strength and 490,920% elongation. The arborescent block copolymers showed surface morphologies ranging from spherical to cylindrical/lamellar nanometer-sized discreet PSt phases dispersed in a continuous PIB matrix, with a 10,nm PIB layer on the surface. Drug release profiles of paclitaxel from two arborescent blocks were found to be similar to that measured from Translute®. Copyright © 2006 John Wiley & Sons, Ltd. [source] Highly Porous Nano- and Microstructured Films Loaded with Bioactive Agents for Biomedical Applications: Structure,Release Profile EffectsADVANCED ENGINEERING MATERIALS, Issue 8 2009Adi Rachelson The current study focuses on the nanostructuring of our new drug-eluting porous films and its effect on the drug release profile of both hydrophilic and hydrophobic drugs. Nanostructuring was obtained using both the dispersion and the condensation methods of emulsion processing. These new highly porous nanostructured films can be used as basic elements of various drug-eluting medical devices. [source] Is there variability in drug release and physical characteristics of amiodarone chloride from different commercially available tablets?INTERNATIONAL JOURNAL OF PHARMACY PRACTICE, Issue 4 2010Possible therapeutic implications Abstract Objectives, Amiodarone is a low-solubility, high-permeability drug with a narrow therapeutic index and reported bioavailability problems associated with switching formulations. The aim of this study was to identify whether there is variability in drug release and physical characteristics of different commercially available amiodarone hydrochloride formulations in Australia. Methods, Four available formulations (innovator Cordarone (COR) and generic products G1, G2 and G3) were tested for drug dissolution, content uniformity, hardness, weight variation, friability and disintegration in accordance with the US Pharmacopeia specifications. Key findings, The tested formulations exhibited variable dissolution behaviours: G1 and G3 exhibited the fastest dissolution, G2 dissolution was the slowest and Cordarone showed a medium dissolution. After 3 months' exposure to high temperature (40 ± 2°C) and relative humidity (75 ± 5%), the products exhibited a higher degree of disparity, with drug-release profiles of the generics being markedly different from that of Cordarone. This suggests possible implications on bioequivalence for patients who live in warm/tropical regional areas. Most products met the US Pharmacopeia specifications for drug-content uniformity and other test physical characteristics. Conclusions, The results suggested that variability in drug release profiles in vitro of amiodarone formulations might be a potential indicator of compromised bioavailability, causing possible interference with the therapeutic response of the drug. [source] Preparation and in vitro evaluation of new pH-sensitive hydrogel beads for oral delivery of protein drugsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010I. M. El-Sherbiny Abstract New biodegradable pH-responsive hydrogel beads based on chemically modified chitosan and sodium alginate were prepared and characterized for the controlled release study of protein drugs in the small intestine. The ionotropic gelation reaction was carried out under mild aqueous conditions, which should be appropriate for the retention of the biological activity of an uploaded protein drug. The equilibrium swelling studies were carried out for the hydrogel beads at 37°C in simulated gastric (SGF) and simulated intestinal (SIF) fluids. Bovine serum albumin (BSA), a model for protein drugs was entrapped in the hydrogels and the in vitro drug release profiles were established at 37°C in SGF and SIF. The preliminary investigation of the hydrogel beads prepared in this study showed high entrapment efficiency (up to 97%) and promising release profiles of BSA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Injectable and thermosensitive poly(organophosphazene) hydrogels for a 5-fluorouracil deliveryJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Sun Mi Lee Abstract The drug solubility and its release profiles of an anticancer drug from an injectable thermosensitive poly(organophosphazene) hydrogel bearing hydrophobic L -isoleucine ethyl ester and hydrophilic ,-amino-,-methoxy-poly(ethylene glycol) with and without hydrolysis-sensitive glycyl lactate ethyl ester or functional glycyl glycine have been investigated. 5-Fluorouracil (5-FU) was used as a model anticancer drug. The aqueous solutions of 5-FU incorporated poly(organophosphazenes) were an injectable fluid state at room temperature and formed a transparent gel at body temperature. The poly(organophosphazene) solution could enhance the solubility of 5-FU and its solubility (34.26 mg/mL) was increased up to 10-fold compared to that in phosphate-buffered saline (3.39 mg/mL, pH 7.4, 4°C). The in vitro drug release profiles from poly(organophosphazene) hydrogels were established in phosphate-buffered saline at pH 7.4 at 37°C and the release of 5-FU was significantly affected by the diffusion-controlled stage. The results suggest that the injectable and thermosensitive poly(organophosphazene) hydrogel is a potential carrier for 5-FU to increase its solubility, control a relatively sustained and localized release at target sites and thus decrease systemic side effects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Chitosan-Pectin Composite Gel Spheres: Effect of Some Formulation Variables on Drug ReleaseMACROMOLECULAR SYMPOSIA, Issue 1 2004Pornsak Sriamornsak Abstract Chitosan-pectin composite gel spheres were prepared by ionotropic gelation method. Pectin solution containing indomethacin, a model drug, was extruded into a mixture of chitosan and calcium chloride. The release behavior of indomethacin from composite gel spheres was investigated in-vitro. The influence of factors affecting release behavior, such as type of pectin, molecular weight of chitosan, cross-linking time and release medium, were discussed in this study. Adding chitosan into gelation medium could retard the release of indomethacin from gel spheres. The different type of pectin used demonstrated slightly different drug release profiles. The higher molecular weight of chitosan showed less indomethacin release than the lower one. The increased cross-linking time slowed the drug release from composite gel spheres. The release of indomethacin from composite gel spheres was also dependent on the release medium. The drug release was slower in tris buffer where no phosphate ions which can induce the precipitation of calcium phosphate. The results suggested that the composite gel spheres of pectin and chitosan could be used as a controlled release drug delivery carrier. [source] The effect of additives on naltrexone hydrochloride release and solvent removal rate from an injectable in situ forming PLGA implantPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2006Raheleh Bakhshi Abstract Biodegradable in situ forming drug delivery systems for naltrexone release are promising for post-treatment of drug addicts. The effect of two different additives, glycerol and ethyl heptanoate, on the naltrexone hydrochloride release and solvent removal from a poly(DL -lactide-co-glycolide) (PLGA) injectable implant is presented in this article. The experimental results showed that the in vitro initial release of the drug was decreased in the presence of these additives. Ethyl heptanoate was, however, more effective than glycerol and increasing the amount of additives in PLGA solution up to 5% (w/w) resulted in a decrease of initial naltrexone release rate up to 50%. The morphological evaluation of implants using scanning electron microscopy indicated that the additives generated a less porous structure together with a finger-like to sponge-like transition. The solvent removal profiles of injectable implants, which can be well described by thermogravimetric and morphological analysis, were in good agreement with drug release profiles. Copyright © 2006 John Wiley & Sons, Ltd. [source] Electrospun starch acetate nanofibers: Development, properties, and potential application in drug deliveryBIOTECHNOLOGY PROGRESS, Issue 6 2009Weijie Xu Abstract Electrospun starch acetate (SA) nanofibers with different degrees of substitution (DS) have been developed using formic acid/water as solvents, and their properties and potential applications in drug delivery have been studied. Although SA is biodegradable, biocompatible, and inexpensive, the mechanical properties and potential applications of SA nanofibers have not been studied. This research studied the effect of the solvent system, SA concentration, annealing time, and DS on the morphology and tenacity of SA nanofibers. The water stability of SA nanofibers and drug release profiles using diclofenac as a model drug with the sorption and the dissolution methods have also been investigated. It has been found that annealing not only increased the mechanical properties of SA nanofibers but also led to a low initial burst and a constant release rate. The results also showed that 90% (v/v) formic acid/water solvent system gave even and fine SA nanofibers and the highest tenacity obtained in this study was 17.9 MPa. The SA nanofibers with DS 2.3 retained about 78.0% and 48.0% of its tenacity after 16 and 32 days exposing to 50°C and 90% relative humidity comparing to 77.0% and 40.2% for SA nanofibers with DS 1.1, respectively. In addition, SA nanofibers with DS 2.3 had a lower initial burst and a more constant drug release rate than those with DS 1.1. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||