The aim of the present study was to prepare and evaluate microparticles of Diltiazem Hydrochloride (DTZ) using blend of HPMC and Eudragit RS 100 by solvent evaporation technique for controlled release. Sieve analysis data indicated that the prepared microparticles were in the ranges of 265 to 187μm. The angle of repose, % Carr’s index and tapped density were well within the limit, indicating reasonable good flow potential for the prepared microparticles. SEM photographs and calculated sphericity factor confirms the prepared formulations are spherical in nature. DSC studies and FT IR spectra showed that the encapsulated drug was stable in the prepared formulations. The prepared formulations were analyzed quantitatively for the amount of encapsulated drug. From the drug loading, encapsulation efficiency and in vitro drug release data, optimum formulation F7 was selected. The optimum formulation shows the drug release of 88.30 % up to 24 h having drug loading and encapsulation efficiency of 56.28% and 91.50 % respectively. It was also observed that, there was no significant release of drug at gastric pH. The release kinetics for all the formulations indicated that drug release followed non -Fickian diffusion. The release performance was greatly affected by the ratio of materials used in preparation of microparticles. Diltiazem Hydrochloride loaded microparticles have desirable release profiles and worthy of further investigation as an oral controlled release dosage form.
