RESUMO
Purpose: Cinnarizine (CIN) is a class II BSC drug, suffering from erratic bioavailability due to its pH-dependent solubility. It has preferential absorption in the stomach. In this study, new chitosan (CS) coated niosomes of CIN (CIN-loaded chitosomes) have been developed to extend the gastric retention and ameliorate CIN oral bioavailability. Methods: Various CIN-loaded niosomes were fabricated by thin-film hydration technique and fully characterized. Based on the predetermined criteria of low particle size (PS) and high entrapment efficiency percent (EE%), niosomal formulation F1 was selected and further coated with different CS concentrations. The optimized chitosomal formulation (C2) was evaluated through solid state characterization and mucoadhesive efficiency testing. It was also subjected to cytotoxicity study on Caco-2 cells; besides, in vitro drug release, stability and pharmacokinetic studies were assessed. Results: The optimized chitosomal formulation (C2) exhibited an EE% of 58.30±2.75%, PS of 440 ±13.03 nm, PDI of 0.335±0.21 and ZP of +28.1±0.10 mv. Solid state characterization results revealed the compatibility between the vesicle components and the entrapment of CIN within niosomal vesicles. C2 formulation demonstrated favorable mucoadhesive efficiency. The cytotoxicity study on Caco-2 cells manifested the safety of the optimized chitosomal formulation (C2) over the free drug. Additionally, it displayed a remarkable sustaining of CIN in vitro release up to 8 h and exhibited a good stability at the refrigerated temperature up to 3 months. In vivo pharmacokinetic assessment revealed that the CIN bioavailability from the optimized chitosomal formulation C2 was enhanced by 2.79 and 1.92 folds compared to the free drug and uncoated niosomal formulation F1, respectively. The priority of the chitosomal formulation (C2) over the niosomal one (F1) was also conferred. Conclusion: Novel formulation of chitosan coated niosomes (chitosomes) could be presented as a promising platform to improve the oral bioavailability of drugs with narrow absorption window.
