Influence of different parameters on drug release from hydrogel systems to a biomembrane model. Evaluation by differential scanning calorimetry technique.
ABSTRACT A comparative study on the drug release capacity of four water swellable polymeric systems was carried out by differential scanning calorimetry (DSC). The polymeric systems chosen were alpha,beta-polyaspartahydrazide (PAHy) crosslinked by glutaraldehyde (GLU) (PAHy-GLU) or by ethyleneglycoldiglycidylether (EGDGE), (PAHy-EGDGE), polyvinylalcohol (PVA) crosslinked by glutaraldehyde (PVA-GLU) and alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) by gamma irradiation (PHEA-gamma matrices). The degree of crosslinking for PAHy-GLU, PAHy-EGDGE and PVA-GLU samples was about 0.4 and 0.8. These hydrogels were characterized as free of drugs and were loaded with diflunisal (DFN) (approximately 2.5% w/w). Diflunisal, a non-steroidal anti-inflammatory drug, has been chosen as a model drug to be incorporated into polymeric matrices to follow the release processes of a drug from these hydrogels to a model membrane made by unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC). Differential scanning calorimetry appears to be a suitable technique to follow the transfer kinetics of the drug from the controlled release system to the biomembrane model. The drug releases from all the considered polymeric hydrogels, were compared with the release observed from the drug solid form by examining the effects on the thermotropic behaviour of DPPC unilamellar vesicles. The release kinetics of the drug from hydrogels were followed at 25, 37 and 50 degrees C to evidence the influence of temperature on the drug release and on the successive transfer to biological membrane model. Particularly, it appears evident that the total amount of drug transferred and the release rate are affected by the polymer crosslinking degree (it increases with crosslinking decrease) as well as by the nature of crosslinking agent. In fact, the drug release profiles from PAHy-GLU samples are more differentiated than those from PAHy-EGDGE. The effect of parameters correlating with the properties of starting polymer, such as water-affinity, crystallinity, glass-to-rubber transition temperature and affinity towards drug molecules, has been also evaluated.
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ABSTRACT: The release of bioactive molecules by different delivery systems has been studied. We have proposed a protocol that takes into account a system that is able to carry out the uptake of a bioactive molecule released during the time, resembling an in vivo-like system, and for this reason we have used biomembrane models represented by multi-lamellar and unilamellar vesicles. The bioactive molecule loaded delivery system has been put in contact with the biomembrane model and the release has been evaluated, to consider the effect of the bioactive molecule on the biomembrane model thermotropic behavior, and to compare the results with those obtained when a pure drug interacts with the biomembrane model. The differential scanning calorimetry technique has been employed. Depending on the delivery system used, our research permits to evaluate the effect of different parameters on the bioactive molecule release, such as pH, drug loading degree, delivery system swelling, crosslinking agent, degree of cross-linking, and delivery system side chains.Journal of pharmacy & bioallied sciences. 01/2011; 3(1):77-88.
- Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
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ABSTRACT: The aim of the present work was to develop and characterize mucoadhesive film of cellulose (methyl cellulose and hydroxy propyl methyl cellulose) and polymethacrylate (Eudragit RSPO) polymers for buccal delivery of carvedilol. Drug and polymers were found to be compatible as revealed by FTIR and DSC analysis. Mucoadhesive films were prepared by solvent casting technique. Swelling studies up to 4h did not show erosion of film, which was further confirmed by SEM analysis. New, simple and precise instrumental methods were established for the evaluation of mucoadhesive strength (33.8±0.37-38.4±0.24g) and film strength (331.2±0.73-369.0±1.00g) of developed films. Mucoadhesive film F5 showed 88±1.15% in vitro drug release and 80±2.30% ex vivo drug permeation through goat buccal mucosa in 12h. Drug release and permeation followed Higuchi's model and mechanism was found to be Fickian type diffusion controlled.Carbohydrate Polymers 07/2013; 96(1):172-180. · 3.48 Impact Factor