Abstract

Diltiazem sustained release pellets were prepared by pan-coating process using nonpareil sugar cores of appropriate size. The drug was dispersed in melted stearic acid (1:1), and the mixture was loaded on the basic sugar cores using polyvinylpyrrolidone (PVP, 10% w/v in water) as the binder. The drug-loaded beads were then coated with ethylcellulose coating solution. Dissolution test was carried out in hydrochloric acid media of pH 1.2 (0.085 M) for the first two hours and then the media was replaced by phosphate buffer of pH 7.2 (0.05 M). The release pattern was diffusion controlled for the formulations having lesser amount of ethylcellulose (SA I, ethylcellulose content 9.09% of the total wt) but shifted towards zero order with the increase in the proportion of ethylcellulose in the formulations. A near zero order release profile was obtained in formulations having higher amount of ethylcellulose (SAIV,28.57% w/w) which was able to sustain the drug-release upto 12 h.