Enhancement of Dissolution Rate of Telmisartan by Solid Dispersion Technique

Abstract

Telmisartan is an angiotensin II type-1 receptor antagonist, used in the treatment of essential hypertension. Telmisartan belongs to class II under biopharmaceutical classification system, characterized by low solubility and high permeability. Oral absorption of Telmisartan is dissolution rate limited and it requires enhancement of solubility and dissolution. The main objective of the present study is to increase the solubility and dissolution rate of telmisartan through solid dispersion technology using various concentrations of water soluble carriers such as poly vinyl pyrrolidone, polyethylene glycol 4000 and poloxomer 407. Solid dispersions were prepared by solvent evaporation technique using methanol as solvent. The enhancement of dissolution rate depends on the nature and concentration of the carrier. The order of increasing dissolution rate with water soluble carriers was poloxomer 407 > polyethylene glycol 4000 > polyvinyl pyrrolidone. Increasing dissolution may be due to the reduced particle size of the drug, enhanced wettability of the drug by hydrophilic carriers. The formulations were evaluated by fourier transform infrared spectroscopy. Telmisartan tablets formulated employing selected solid dispersions gave higher dissolution than the plain tablets.