Thermosensitive in situ nanocomposite of rivastigmine hydrogen tartrate as an intranasal delivery system: Development, characterization, ex vivo permeation and cellular studies.

Intranasal administration of pharmaceutical compounds is gaining considerable attention as an alternative route for localized/systemic drug delivery. However, insufficient therapeutic efficacy of drugs via this route seems to be a major challenge for development of de novo intranasal formulations. This shortcoming can be overcome by simultaneous utilization of a nanoparticulate delivery system with a polymeric gel network. Therefore, the main aim of the present study was to develop erodible in-situ gel forming systems of poloxamer 407® (P407) as a promising platform, capable of prolonging rivastigmine hydrogen tartrate (RHT) release from the embedded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). PLGA NPs containing RHT were formulated and characterized, then were embedded in P407 gel forming matrix and analyzed in terms of viscosity, stability, gelation temperature, loading efficiency and mucoahesive behavior. The cytotoxicity of NPs was evaluated on A549 cell line using MTT assay. Cellular uptake of the NPs was also measured by means of fluorescence microcopy and flow cytometry analyses. The formulations were finally evaluated for their permeability across sheep nasal mucosa. A linear dependence of sol-gel temperature (Tsol-gel) on the P407 concentration was observed, and a P407 content of 18% was selected. The loading efficiencies of formulations were found to be around 100.22-104.31%. The RHT-loaded NPs showed a suitable cytocompatibility on A549 cells with a time-dependent increase in cellular uptake. Besides, nanocomposites showed higher amounts of drug permeation through nasal sheep mucosa than plain drug gel. Taken all, it is concluded that the formulated nanocomposites may be considered as useful drug delivery systems for the nasal delivery of RHT with enhanced therapeutic efficacy.