FORMULATION AND EVALUATION OF BILAYER TABLET OF VALSARTAN & SPIRULINA

Abstract

The objective of present study was to formulate and evaluate bilayer tablet of Valsartan (VS) and Spirulina (SP) for treatment of hypertension and diabetes. The combination of Valsartan and Spirulina is used, as Valsartan establishes the immediate release layer (initial dose) and Spirulina as sustained release layer (maintenance dose) respectively. The bilayer tablets of VS and SP was particularly designed to minimize the risk of hypertension, diabetes and improve the therapeutic efficacy and to prolong the drug release and patient compliance. The formulation variables for immediate release layer include sodium starch glycolate and crospovidone as super disintegrants and micro crystalline cellulose as filer. HPMC K100, HPMC E15, was used as polymers for sustained release. The result of in-vitro release data showed that HPMC K100 can sustain the drug release up to 12hrs. From these studies HPMC K100 has been selected for further studies of bilayer tablet. Valsartan and Spirulina bilayer tablets were prepared by direct compression method. The hardness of the bilayer tablets was found to be 6.30±0.02kg/cm2. The thickness of the bilayer tablets was found to be 3.15±0.02mm. The drug content of Valsartan and Spirulina was 98.10±0.90 (SR) and 98.84±0.09 (IR). The in-vitro drug release of bilayer tablets has Valsartan immediate release was within 45minutes and Spirulina from the tablets was found sustained over 12 hours with Zero order equation to analyze the release pattern of the drug from the polymeric system. The value of “n” was in the range of 0.1531, indicating the drug release followed fickian release. Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the chemical interactions between the drugs and excipients were absent. The results of Accelerated stability studies showed that all parameters were within the expected specifications and there were no significant changes observed from initial to 3 month, indicating good stability.