No abstract

The objective of the present investigation is to develop and evaluate polyethylene-starch based carriers for sustaining the release of bioactive materials. Polyethylene-starch carriers were prepared by incorporating various amounts of corn starch 0, 40, 80, and 100% in polyethylene beads with and without dye. Acid orange dye was incorporated (1%) to study release patterns and the effect of starch (%) on release. The granulated mixtures were extruded to form uniform dispersions of starch and polyethylene throughout the extrudate. The extrudates obtained were studied for SEM surface characterization before, during, and after release studies to study the erosion process. In the case of 100% starch, 80% of the matrix was eroded in 5 weeks, while with 40% and 80% starch, erosion was less than 20%. The dye release studies showed that release could be sustained well over 12 weeks, depending on the starch (%) incorporated. The erosion process was studied using scanning electron microscopic techniques, which showed gradual erosion of starch particles, leaving a polyethylene skeleton. These materials show promising potential for use as carriers for bioactive materials.

The present communication deals with the study of the effect of pH on the drug release characteristics and the drug release kinetic from the RHPC (Rosin Hard Paraffin Combination) coated aspirin microcapsules. For the purpose of the present study the aspirin microcapsules were prepared by pan coating method imparting 15 coats using 10 per cent RHPC solution in acetone. A standard coating procedure was used to coat the aspirin granules. Dissolution studies were carried out in media with different pH. To get a clear picture drug release studies were conducted in each media for 3 h. The results showed that the RHPC films were resistant to acidic pH releasing less than 5 per cent and 15 per cent drug in 3 h in pH 1.2 and 3.0 respectively. The T 50% in pH 5.0 media was 163 min. The drug was released very quickly in pH 7.2 and 8.0. The release kinetic study showed that the release followed the classical first order pattern though the coated microcapsules used to be intact during the dissolution process, in case of the acidic pH media. The release kinetic was changed when the pH of the dissolution media was 7.2 and above. It was found that during the dissolution process the granules undergo erosion and the release mechanism does not follow a single process.