Formulation Design, Optimization and Evaluation of Carvedilol Phosphate Gastro Retentive Floating Tablets

The main objective of present research work is to formulate the floating tablets of Carvedilol Phosphate using 32 factorial design. Carvedilol Phosphate, non-selective α1-β1-blocking agent belongs to BCS Class-II and Indicated for treatment of Hypertension/moderate Heart Failure. The Floating tablets of Carvedilol Phosphate were prepared employing different concentrations of HPMCK100M and Sodium bicarbonate in different combinations by Direct Compression technique using 32 factorial design. The concentration of HPMCK100M and Sodium bicarbonate required to achieve desired drug release was selected as independent variables, X1 and X2 respectively whereas, time required for 10% of drug dissolution (t10%), 50% (t50%), 75% (t75%) and 90% (t90%) were selected as dependent variables. Totally nine formulations were designed and are evaluated for hardness, friability, thickness, % drug content, Floating Lag time, In-vitro drug release. From the Results concluded that all the formulation were found to be with in the Pharmacopoeial limits and the In-vitro dissolution profiles of all formulations were fitted in to different Kinetic models, the statistical parameters like intercept (a), slope (b) & regression coefficient (r) were calculated. Polynomial equations were developed for t10%, t50%, t75%, t90%. Validity of developed polynomial equations were verified by designing 2 check point formulations (C1, C2). According to SUPAC guidelines the formulation (F8) containing combination of 25% HPMCK100M and 3.75% Sodium bicarbonate, is the most similar formulation (similarity factor f2=88.801, dissimilarity factor f1= 2.250 & No significant difference, t= 0.095) to marketed product (CARDIVAS). The selected formulation (F8) follows Higuchi's kinetics, and the mechanism of drug release was found to be Non-Fickian Diffusion (n= 1.035, Super Case-II transport).