RESUMO
Nasal drug delivery has the potential to improve the systemic bioavailability of drugs with low oral bioavailability. Olmesartan medoxomil (OLM) is one of the most popular drugs for the treatment of hypertension with poor oral bioavailability of approximately 26 %. In this context, the goal of this work was to synthesize chitosan nanoparticles (CS NPs) loaded with OLM using the ionotropic gelation method to enhance the bioavailability and decrease oral side effects through nasal route. The particle size (PS), zeta potential (ZP), entrapment efficiency (%EE), and ex-vivo transmucosal permeation study of CS NPs were all evaluated. The pharmacokinetic and pharmacodynamic studies of selected formula compared to oral and nasal OLM suspensions were conducted. Successful formation of spherically shaped OLM CS NPS in the nano-range (240.02-344.45 nm) favorable for the intranasal absorption with high %EE (75.2-83.51 %) was achieved. The ability of OLM CS NPs to permeate efficiently across the nasal mucosa was proven in an ex vivo permeation experiment. Pharmacokinetic study demonstrated that the intranasal administration of OLM CS NPs exhibited improved bioavailability by 11.3-folds relative to oral OLM suspension as indicated by higher AUC value. The superior effect of intranasal OLM CS NPs was also accentuated in l-NAME induced hypertensive rats compared to intranasal and oral OLM suspension by reducing the high blood pressure (BP) and improving the heart rate (HR) of the induced group. Histological examinations revealed no damage occurred to nasal mucosa. In conclusion, OLM CS NPs had the ability to significantly improve the bioavailability of OLM and decrease BP and HR, suggesting the potential application of CS NPs as a promising carrier for the systemic delivery of OLM via intranasal route.