Solid Dispersion of Telmisartan Using Full Factorial Design

Telmisartan is an angiotensin II (AT1) receptor antagonist used in the treatment of hypertension. The drug is practically insoluble in water and insoluble in the pH range 3-9. The principal aim of this work is to improve the dissolution profile of telmisartan by solid dispersion and to find out the effect of sodium starch glycolate and β – cyclodextrin on the dissolution profile of telmisartan tablets. The study also includes optimization of the amount of sodium starch glycolate and β – cyclodextrin by a 32 full factorial design. Other excipients used in the study are microcrystalline cellulose (Avicel PH-101), D- mannitol, magnesium stearate and talc. Both sodium starch glycolate and β – cyclodextrin had contribution towards the enhanced release profile of telmisartan (about 80 % drug is released in 40 minutes) but the effect of β – cyclodextrin is more pronounced as revealed from response surface plots as well as from their corresponding contour plots. The optimized amount of β – cyclodextrin and sodium starch glycolate was found to be 2.0 gm and 1.6 gm respectively. The predicted and observed responses for the optimized solid dispersions shown no significant difference (paired t-test, p – value = 0.2834 and 0.3403 for percentage drug released at 20 and 40 minutes respectively).