IN VIVO EVALUATION OF QUINAPRIL TRILAYERED MATRIX TABLETS
Objective: The aim was to design, formulate, and evaluate the trilayer matrix tablets incorporated with quinapril for extend drug release. Methods: Quinapril trilayer matrix tablets were formulated using design of experiment software wherein initially 27 formulations (QF1-QF27) were designed for active layer from which one best formulation was chosen based on drug content, swelling index and in vitro release studies. The chosen formulation was formulated into extended release trilayed matrix tablet by varying proportions of polymers by direct compression and was evaluated for various physicochemical parameters, drug release. Best formulation was characterized for Fourier transform infrared (FTIR), stability, and pharmacokinetic study. Results: Out of 27 formulations highest drug release was exhibited by QF16 (98.85%) which was formulated into trilayer matrix tablets (AQF16- HQF16). Out of which EQF16 was found to exhibit highest values with 98.42% swelling index, 99.56% drug content, and 99.72% drug release in 24 h. All quinapril trilayer formulations showed zero-order and first-order for marketed product. The optimized formulation EQF16 was found to exhibit no interaction with excipients interpreted by FTIR and no significant changes were observed after loading for stability. In vivo studies conducted using optimized formulation EQF16 attained peak drug concentration (Tmax) of 4.0±0.06 and 1.0±0.03 h for the optimized and commercial formulations, respectively, while mean maximum drug concentration (Cmax) was 302.64±0.07 ng/mL and was significant (p<0.05) as compared to the quinapril marketed product formulation 358.78±0.75 ng/mL. Conclusion: Hence, quinapril was successfully formulated into trilayer matrix tablet and found to be stable.