The in vitro evaluation of gelatin coacervate microcapsules

Abstract

Microcapsules of sulphadiazine have been prepared by the simple gelatin coacervation technique, using sodium sulphate as coacervating agent. The free flowing microcapsular material was hardened with formalin. There is no direct relation between particle size and sulphadiazine concentration nor between different starting gelatin percentages. The effects on size of hardening time, temperature and sampling time are small. In vitro dissolution studies show that first order release characteristics are exhibited by all the hardened materials. Temperature and pH effects indicate the dissolution of the sulphadiazine itself to be the controlling step rather than the rate of diffusion through the microcapsule wall.