The objective of this study is to develop an oral formulation of famotidine niosomes coated with a mucoadhesive polymer, chitosan. Famotidine (FMT) has low oral bioavailability of 40-45% and short half-life between 2.5 to 4 h. Famotidine is classified as class IV in BCS because of its low aqueous solubility (0.1% w/v) and low permeability. Thus, FMT was loaded to the bioadhesive coated niosomes to improve its solubility, enhance its oral bioavailability, and sustain FMT release pattern. Different formulations were prepared by thin-film hydration method and characterized in terms of entrapment efficiency, morphological features, vesicle size, and zeta potential. In vitro release and ex vivo permeability of famotidine from the formulations were evaluated. The optimized formula was coated with chitosan and its mucoadhesion and stability in bile salt was tested. The optimized formula showed a high entrapment efficiency of 74%, as well sustained the in vitro release of FMT in the simulated gastric medium and enhanced its permeation through an excised goat's intestinal membrane by 1.4 fold in comparison to FMT control suspension. The mucoadhesive coated formula exhibited a significantly higher (p < 0.05) mucoadhesive efficiency and more stability in the bile salt as compared to the uncoated formula. Therefore, it could be considered as an efficient delivery system to maintain the prolonged release of FMT and improve its oral bioavailability.
Keywords: bioadhesion; chitosan; famotidine; niosomes; sustained.