The Use of Polyglycol Succinates for the Microencapsulation of Insulin

Since the discovery of insulin and establishment of its value in the treatment of diabetes mellitus, many investigators have explored the possibility of developing an effective method for its administration other than by injection. The reason is that the necessary injections of the hormone are not only inconvenient but also result in physiological complications as well. In this study, the possibility of an oral administration of insulin was investigated. A group of biodegradable polymers from polyglycal succinates family wassynthesized by bulk polycondensation reaction of glycols with diethyl succinate. The polymers were purified and used for microencapsulation ofinsulin. The size and shape of microcapsules were studied with optical and electron scanning microscope. The rate of release of core material from the microcapsules was measured by a direct UV absorption method. It was found that pH of the environment, microcapsules wall thickness and the type of glycol used in the polymerizations are the most important factors on the controlled release.