FORMULATION AND EVALUATION OF SUSTAINED RELEASE TABLETS OF LABETALOL HYDROCHLORIDE USING HYDROPHILIC POLYMERS

Abstract

Labetalol hydrochloride is used in treatment of hypertension. It has a short half-life and undergoes extensive first pass metabolism. In the present study, labetalol hydrochloride 100 mg controlled release matrices were prepared by direct compression and in vitro drug dissolution studies were performed to find out the drug release rate and patterns. Hydroxypropyl methylcellulose, Hydroxypropyl cellulose and Hydroxyethyl cellulose were used as rate controlling polymers. Hydroxypropylmethylcellulose was used as primary rate controlling polymer and effects of addition of Hydroxypropyl cellulose and Hydroxyethyl cellulose on in-vitro drug dissolution were studied.  Tablets were formulated using total polymer content as 30, 35 and 40 percent with 20 percent standard polymer content of Hydroxypropyl methylcellulose in all batches and varying the concentration of Hydroxypropyl cellulose and Hydroxyethyl cellulose in the range of 10, 15 and 20 percent. In-vitro drug release was carried out using USP Type II at 50 rpm in 900 ml of acidic dissolution medium (pH 1.2) for 2 hours, followed by 900 ml alkaline dissolution medium (pH 7.4) up to 12 hours. Several kinetic models were applied to the dissolution profiles to determine the drug release kinetics.

KEYWORDS: Labetalol Hydrochloride , Hydroxypropyl methylcellulose, Hydroxypropyl cellulose, Hydroxyethyl cellulose, Release Kinetics.