FORMULATION AND EVALUATION OF SUSTAINED RELEASE PELLETS OF DILTIAZEM HYDROCHLORIDE

The aim of the present study was to develop sustained release (SR) pellets of Diltiazem hydrochloride (DTZ) with aqueous dispersion of ethyl cellulose (Aquacoat ECD 30) as the release rate retarding polymer by fluidised bed coating (FBC) technique. The drug was loaded by pan coating. The prepared pellets were evaluated for appearance, percent yield, loss on drying, drug content, particle size analysis, pellets shape, physical properties such as bulk density, tap density, flow rate, Hausner's ratios, Compressibility Index, angle of repose, in vitro drug release and were found to be within the limits. The mean particle size of the pellets was in the range 600 - 850 μm. The drug excipient compatibility was determined by fourier transform infrared (FTIR), differential scanning calorimetry (DSC) studies and found to be compatible. Pellets were characterized for particle surface and surface texture using scanning electron microscope (SEM) which revealed that the coated pellets were discrete, spherical with a uniform coating. The pellets filled in hard gelatin capsules were evaluated for weight variation, locking length, average net weight, drug content, in vitro drug release and found to be within the range. Stability studies were carried out on the optimized formulation and were found to be stable for a period of 3 months.