Preclinical Pharmacokinetic Evaluation of Valsartan Floating Tablets Formualted Using Cross Linked Starch Urea - A New Modified Starch

The objective of the present study is optimization of valsartan floating tablet formulation by 2 3 factorial design and to evaluate the optimized valsartan floating tablets for in vitro drug release, preclinical pharmacokinetics and also for in vitroin vivo correlation (IVIVC). Valsartan is an orally active anti-hypertensive drug, majorly absorbed from stomach and upper small intestine. Formulation of sustained release floating tablets of valsartan is needed because of its poor oral bioavailability and short biological half-life. Valsartan floating tablets were formulated as per 2 3 factorial design and were evaluated. Valsartan floating tablets prepared as per 2 3 factorial design were non-disintegrating in water and aqueous acidic (pH 1.2) and alkaline (pH 7.4) fluids and were of good quality with regard to drug content, hardness, friability and suitable for controlled release. Formulations Fa, Fab, Fac and Fabc exhibited excellent floating over >12 h with a floating lag time in the range 12-40 seconds. Higher levels (20 %) of sodium bicarbonate gave shorter floating lag time. Valsartan release from the floating tablets prepared except formulation Fa was slow and spread over 12 h and dependent on the composition of the tablets. Drug release from formulation Fa was very rapid. Valsartan release from the floating tablets was by non-fickian diffusion mechanism in all the cases except Fa. In the case of formulation Fa that gave rapid release of drug fickian diffusion was the drug release mechanism.