Formulation and In Vitro Evaluation of Sustained Release Microspheres of Diltiazem Hydrochloride Prepared by Emulsification-Internal Gelation Method

The present work describes the formulation of alginate microspheres containing diltiazem hydrochloride by the emulsification-internal gelation method with the use of barium carbonate as a cross-linking agent. The effect of various factors (the concentration of alginate and barium chloride) on the drug loading efficiency and in vitro release were investigated. Fourier transform infrared microscopy (FTIR) and differential scanninig calorimetry (DSC) analysis confirmed the absence of any drug polymer interaction. X-ray diffraction (XRD) pattern showed that there is a decrease crystallinity of the drug. The in vitro drug release profile could be altered significantly by changing various processing parameters to give a controlled release of drug from microcapsules. The stability studies of drug-loaded microcapsules showed that the drug was stable at different storage conditions.