Enhancement of Dissolution of Telmisartan by Surface Solid Dispersion Technique

Telmisartan is an Angiotensin Receptor Blocker (ARB) used for the treatment of hypertension. It belongs to BCS class-II i.e. low solubility and high permeability and exhibits variable bioavailability. The objective of the present study was to prepare surface solid dispersions of telmisartan to improve its aqueous solubility and dissolution rate. Water insoluble carriers like Avicel pH 101, Crospovidone, Sodium starch glycolate, Cab-o-sil, Pregelatinised starch and Potato starch were used to form surface solid dispersion (SSD) of Telmisartan by solvent evaporation method. The surface solid dispersion prepared with Cab-o-sil in the drug : carrier ratio of 1:10 showed highest dissolution rate as compared to pure drug and physical mixture. The SSD on Cab-o-sil was characterized by Powder X-ray diffractometry, Differential scanning calorimetry, Fourier transform infrared spectroscopy and Scanning electron microscopy. DSC studies revealed that there was no chemical interaction between drug and the carrier and XRD studies demonstrated that there was a significant decrease in crystallinity of pure drug .The optimized surface solid dispersion was compressed into tablets and evaluated for Weight variation, Hardness, friability, Drug content, Disintegration time and Dissolution rate. These tablets exhibited higher rates of dissolution and dissolution efficiency as compared to marketed tablets.