Abstract

ENHANCEMENT OF SOLUBILITY, DISSOLUTION RATE AND FORMULATION DEVELOPMENT OF TELMISARTAN TABLETS EMPLOYING ? CD

K. P. R. Chowdary*, K. Ravi Sankar and M. Gowthami

Abstract

Telmisartan is a widely prescribed anti-hypertensive drug belongs to BCS class II and exhibit low aqueous solubility and poor oral bioavilability. It needs enhancement in solubility and dissolution rate in its formulation development to achieve maximum therapeutic effect. The objective of the study is to enhance the solubility and dissolution rate of telmisartan by complextion with βCD and to develop Telmisartan- βCD tablets with fast dissolution rate comparable to the market branded products. . The effect of βCD and its concentration on the aqueous solubility of telmisartan was evaluated by phase solubility studies. Telmisartan- βCD complexes in various ratios such as 1:1, 1:2 and 1:3 were prepared by kneading method. The dissolution rate of the Telmisartan- βCD complexes prepared was evaluated in comparison to pure drug. Telmisartan- βCD tablets were prepared by direct compression method and were evaluated in comparison to a market branded product. The aqueous solubility of telmisartan was increased linearly as the concentration of βCD was increased. The phase solubility diagram of telmisartan –βCD (Fig.1) can be classified as type AL. Telmisartan formed a 1:1 M complex in solution with βCD with a stability constant (Kc) of 700 M-1. Telmisartan-βCD complexes prepared by kneading method gave much higher dissolution rates than telmisartan pure drug. A 6.95 fold increase in the dissolution rate (K1) was observed with Telmisartan- βCD (1:3) complexes. Telmisartan- βCD tablets prepared disintegrated rapidly within 1min 30sec and gave very rapid dissolution of telmisartan, 86.85 % in 10 min. The dissolution rate of formulated Telmisartan- βCD tablets was higher than that of market branded product tested. Complexation with βCD could be used to enhance the solubility and dissolution rate of telmisartan, a poorly soluble BCS class II drug and to formulate telmisartan tablets with fast dissolution rate characteristics.

Keywords: Telmisartan tablets, ?-cyclodextrin, Solubility, Dissolution rate, Formulation development, Cyclodextrin complexation.