FORMULATION AND EVALUATION OF SUSTAINED RELEASE MATRIX TABLETS OF LOSARTAN POTASSIUM

Sustained release tablets of Losartan potassium (LP),an anti-hypertensive drug were prepared by direct compression method using different polymers such as Carbopol 934P, HPMC K100 M and Locust Bean Gum in different ratios. The compressed tablets were further evaluated for uniformity of weight, hardness, friability, thickness, content uniformity, in-vitro dissolution, swelling index study. In vitro release studies were conducted in phosphate buffer pH 6.8. To analyze the release mechanism Zero-order, First-order, Higuchi, and Korsmeyer-Peppas model were used. Similarity factor f2 was also calculated to compare the prepared matrices with the marketed product. All the formulations exhibited sustained drug release for 12 hrs. Majority of designed formulations followed Zero-order release kinetics and Korsmeyer- Peppas equation gave release pattern with n values greater than 1 indicating super case transport mechanism.The optimized formulation F5 was chosen based on acceptable physical properties, in vitro drug release profile and calculation of similarity factor. Among the three polymers used to formulate matrix tablets of LP, HPMC K100M was found to impart controlled release of drug with desired dissolution profile in 12hrs. Keywords: Losartan Potassium, anti-hypertensive, controlled release, zero order, HPMC K100