Accelerated stability of sulphamethoxazole microcapsules coated with Eudragit RS 100 and Eudragit RL 100

Eudragit is being used as coating material in Microencapsulation technique for sustained release microcapsule formulation. In the present study, we have concentrated in evaluating the stability parameters of the Sulphamethoxazole microcapsules coated with Eudragit RS 100 and RL 100. Two sets of sample were studied, the first set was stored at room temperature for ten years and the second set is freshly prepared one. The second set of samples was subjected to various storage conditions for a period of six months. The samples were analyzed for drug content, dissolution, surface properties and physical properties. It was found that 70% of the core material is still intact in the ten year old sample. Similarly, dissolution studies of the ten year old sample of sustained release microcapsule showed that the drug release ranges from 4% in the first hour to 65% at the end of 8th hour. Whereas, the drug release from the freshly prepared microcapsule (keeping the manufacturing parameters same as that followed for old sample) ranged from 25% in the first hour to 98% at the end of 8th hour. IR spectra of the freshly prepared microcapsules and that of the ten year old microcapsules were found to be identical which shows that no interaction has occurred between the coating polymer and core substance even after ten years.