Studies on almond gum and gelucire based pellets prepared by extrusion and spheronization for sustained release

INTRODUCTION: The aim of the investigation is to prepare sustained release pellets of diltiazem hydrochloride employing almond gum and gelucire. The study was performed to explore the suitability of almond gum in the preparation of pellets of diltiazem hydrochloride without the use of microcrystalline cellulose and role and effectiveness of hydrophobic gelucire (43/01) in controlling the drug release.
METHODS: Pellets were prepared by extrusion–spheronization of the blend previously obtained by incorporation of the drug in a mixture of melted Gelucire 43/01 and almond gum. A 3˛ factorial design was employed to study the effect two independent variables, almond gum and gelucire on the size, friability and drug release from pellets. Scanning electron microscopy, differential scanning calorimetry and infra-red spectroscopy were performed to characterize pellets

RESULTS: Free flowing spherical pellets could be prepared. The 3˛ factorial study revealed that as the proportion of almond gum increased, the size of pellets increased while increasing gelucire had opposite effect. The yield of pellets prepared in different formulations is in the range of 86 to 92 %. The size of pellets varied from 1128 to 1458 µ. Higher amounts of gelucire resulted in pellets with more friability whereas increasing the amount of almond gum yielded pellets with low friability. The pellets exhibited sustained release of diltiazem and the presence of gelucire in the matrix of the pellets had an enhanced sustaining effect on release.
DISCUSSION AND CONCLUSION: Dispersion of the drug in gelucire before it is converted to pellets resulted in extended release of drug. The drug release rate changed with changes in the proportion of pellet composition. The results of the study suggest that employing gelucire (43/01) in the preparation of pellets is a useful approach in the design of sustained release products of highly water soluble drug such as diltiazem hydrochloride.