A QbD approach for the fabrication of immediate and prolong buoyant cinnarizine tablet using polyacrylamide-g-corn fibre gum

The main hurdle in the oral delivery of cinnarizine is its supersaturation, precipitation and re-dissolution process, influencing the oral bioavailability. To overcome this problem, an attempt was made to develop immediate and prolong buoyant tablet of cinnarizine. For this purpose, polyacrylamide-g-corn fibre gum (p-CFG) was synthesized as mucoadhesive cum swellable polymer and it was compared with already used HPMC K4M polymer. The central composite design with two numeric and one categorical factor was choosen to optimize conc. of p-CFG (X1), concentration of NaHCO3 (X2) and type of effervescent agents (X3). The bioadhesive strength of p-CFG tablet was 2.4 times higher than HPMC K4M containing tablet. The formulation composition comprises of p-CFG (64.3%), sodium bi‑carbonate (12.9%) and citric acid (2%) (FCNZ) fulfilled the maximum requirement of an optimized formulation. The in-vivo animal pharmacokinetic performance revealed larger plasma half-life and reduced elimination rate as compared to CNZ suspension. Interestingly, the absorption of CNZ from optimized formulation was 3 times enhanced than from CNZ suspension. Overall, the enhancement in the oral bioavailability of CNZ was evident that is due to its prolonged gastric residence time. Furthermore, the swelling associated floating followed by mucoadhesive nature of tablet was observed by X-ray imaging studies.