Formulation and Evaluation of Buccoadhesive Tablets of Losartan Potassium

The present investigation is concerned with formulation and evaluation of buccoadhesive tablets containing antihypertensive drug, Losartan Potassium to avoid the first pass effect and to improve its bioavailability with reduction in dosing frequency and dose related side effects. The tablets were prepared by wet granulation method. Nine formulations were developed with varying concentrations of polymers like hydroxypropylmethyl cellulose K100 and Guar gum. The tablets were tested for hardness, friability, weight variation, content uniformity, surface pH, swelling index, ex vivo mucoadhesive strength, in vitro drug dissolution study and ex-vivo permeation study. FTIR and DSC studies showed no evidence on interactions between drug and excipients. The in vitro release of Losartan Potassium was performed under sink conditions. The mucoadhesive strength of formulation F9 was found to be 0.14307 N. The swelling index of formulation F9 was found to be 87%. The formulation F9, containing 25 mg of losartan potassium exhibited 6 h sustained drug release of 96% with desired therapeutic concentration. The in vitro release kinetics studies revealed that all formulations fits well with zero order kinetics followed by KorsemeyerPeppas model and the mechanism of drug release is NonFickian diffusion. Based on the results of ex vivo mucoadhesive strength and swelling index studies formulation F9 was selected as optimized formulation and subjected for stability study. Short-term stability studies on the promising formulation indicated that there are no significant changes in drug content and in vitro dissolution characteristics.