Formulation Development and Evaluation of Valsartan Sodium Sustained Release Tablets

Sustained release tablets and capsules are commonly taken only once or twice daily, compared with counterpart conventional forms that may have to take three or four times daily to achieve the same therapeutic effect. Typically, sustained release products provide an immediate release of drug that promptly produces the desired therapeutic effect, followed by gradual release of additional amounts of drug to maintain this effect over a predetermined period. The sustained plasma drug levels provide by sustained release products often times eliminates the need for night dosing, which benefits not only the patients but the care given as well. Sustained Release tablets were compressed without any problem and do not require any change in ratio of excipients in formulation. Results of the present study demonstrated that combination of both hydrophilic and hydrophobic polymers could be successfully employed for formulating sustained release matrix tablets of Valsartan Sodium. The drug release rate was almost similar with HPMC and plastic Vinyl pyrrolidone vinyl acetate Sustained Release tablets. All the formulations have shown drug release in 12 hrs. The formulation F4 have been choosen as optimum preparation with higher drug release and enhanced bioavailability. Majority of formulations have released the drug by Non Fickian diffusion. The formulation with Ethyl Cellulose has shown low drug release and has the problem of dose dumping. The formulation with HPMC has shown similar drug release as that of Vinyl pyrrolidone vinyl acetate but does not follow the theoretical drug release profile. Micro crystalline cellulose used as a diluents does not show any effect on the drug release pattern. Optimized formulation F4 which includes Vinyl pyrrolidone vinyl acetate has successfully sustained the drug release for 12 hours and the drug release pattern was similar to theoretical release profile.