Intranasal drug delivery of didanosine-loaded chitosan nanoparticles for brain targeting; an attractive route against infections caused by AIDS viruses.

The primary aim of this study was to investigate intranasal (i.n.) administration as a potential route to enhance systemic and brain delivery of didanosine (ddI). A further aim was to investigate the potential use of chitosan nanoparticles as a delivery system to enhance the systemic and brain targeting efficiency of ddI following i.n. administration. Didanosine-loaded chitosan nanoparticles, were prepared through ionotropic gelation of chitosan with tripolyphosphonate anions, and characterized in terms of their size, drug loading, and in vitro release. The nanoparticles were administered i.n. to rats, compared to i.n. and intravenous (i.v.) administration of ddI in solution. The concentrations of ddI in blood, CSF, and brain tissues were analyzed by ultra performance liquid chromatography mass spectroscopy (UPLC/MS). The brain/plasma, olfactory bulb/plasma and CSF/plasma concentration ratios were significantly higher (P < 0.05) after i.n. administration of ddI nanoparticles or solution than those after i.v. administration of didanosine aqueous solution. The ratio of ddI concentration values of the nanoparticles to the solution at 180 min post-i.n. dosing was 2.1 and 1.9 in CSF and brain, respectively. Thus, both the i.n. route of administration and formulation of ddI in chitosan nanoparticles increased delivery of ddI to CSF and brain.