In vitro release kinetics study of diltiazem hydrochloride from pellets using an ethylcellulose pseudolatex coating system

In the present study an attempt has been made to investigate the effect of ethylcelluloses a rate retarding material to sustain the release of diltiazem hydrochloride from pellets prepared by air suspenside technique. Aqueous ethylcellulose dispersion (Surelease) with different weight ratios was chosen to sustain the release of the drug. Drug was loaded on dummy seeds by following matrix system as well as barrier coatitig system. The comparative study of this two manufacturing processes was also the goal of this study. In vitro dissolution studies were carried out using USP dissolution apparatus Type-2. The release of drug was faster from matrix system than that of barrier coating system. About 100% drug was released within 3 hours with 5% polymer load from both systems. While the polymer content was 10%, about 4h & 7h required for 50% & 80% drug release respectively from barrier coating system. The effect of ethylcellulose on the release of diltiazem hydrochloride was found to be predominant in barrier coating system than that of the matrix system In the matrix system the drug comes to dissolution media easily and water soluble additives form channel very fast. The kinetic study of the drug was performed and it was revealed that the release of drug from pellets appeared to follow zero order kinetics.