title: pH-sensitive microcapsules for drug release.
abstract: Microcapsules were designed for a sustained drug release, where the external medium controls the rate of release of the drug. As a model, secretin was encapsulated in acryloyl chloride-lysine capsules, and the conditions of formation are described. The scanning electron micrographs show the formation of good spherical microcapsules in the size range of 5-10 microns. The release of secretin was studied in four media having different pH. Polymer dissolution was pH sensitive, and the capsules placed in different media eroded at a constant rate, depending on the pH of the medium. Dissolution of the microcapsules was limited to the polymer buffer media and the drug was released by zero-order kinetics. The possible use of such a system is in the treatment of duodenal ulcers and the diagnosis of pancreatic diseases.
mesh_terms: D000179:Acrylates; D002214:Capsules; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D006863:Hydrogen-Ion Concentration; D008239:Lysine; D008855:Microscopy, Electron, Scanning; D011108:Polymers; D012633:Secretin; D012995:Solubility
chemical_list: D000179:Acrylates; D002214:Capsules; D003692:Delayed-Action Preparations; D011108:Polymers; D012633:Secretin; C026200:acryloyl chloride; D008239:Lysine