Role of Cogrinding in Enhancing the In vitro Dissolution Characteristics of Carvedilol

In the present study, an attempt was made to increase the in vitro dissolution rate of carvedilol (antihypertensive) by cogrinding technique using various carriers, namely lactose, corn starch, treated agar, microcrystalline cellulose. The coground mixtures were prepared using the above excipients in four drug-carrier ratios, viz., 1:1, 1:3, 1:4 and 1:9. The prepared coground mixtures were evaluated for drug content, in vitro dissolution characteristics, short-term stability and drug-carrier interaction (by FTIR). The coground mixtures MCC9 and TAG9 prepared with a drug-carrier ratio of 1:9 using microcrystalline cellulose and treated agar respectively, showed promising results in enhancing the dissolution rate of carvedilol and released nearly 80% of drug within 30 min. Tablets prepared from the above coground mixtures showed two-three times faster dissolution compared to the commercial conventional tablet formulation of carvedilol, when t50% and t70% values were considered. Short-term stability studies on these tablet formulations showed no significant changes in the drug content and t70% values (p<0.05). From the present study, it can be concluded that cogrinding technique can be used for enhancing the dissolution rate of poorly water soluble drug carvedilol providing nearly first order drug release.