Optimization of Controlled Drug Release Through Micropelletization

Abstract

Micropelletization technique using crosslinked gelatin matrix was chosen to evaluate its utility in controlled release medications. Trimethoprim, which has a very high solubility gradient in gastric pH, was selected in this investigation. Micropellets were formed by the modified spray congealing technique. The effects of exposure of the crosslinking agents to the gelatin matrix of the micropellets on the effectivity as the controlled release drug delivery system were investigated. The total product yield, content uniformity and the reproducibilty of the sucessive batches were decidedly superior to either the pure drug or the non-crosslinked ones. Particle size distribution was observed to vary depending on the content of the crosslinked gelatin in the micropellets. Scanning electron micrographs confirmed the porous surface topography of the micropellets. The drug release characteristics was suggested as the diffusion controlled first order dissolution process.