Intranasal mucoadhesive buspirone formulation: in vitro characterization and nasal clearance studies

Oral administration is unsuitable for drugs prone to extensive first-pass metabolism, like buspirone. Thus, in the present study an attempt has been made to develop a mucoadhesive intranasal formulation improving permeation characteristics of buspirone HCl. Nasal formulations containing different concentrations of chitosan HCl and hydroxypropyl-beta-cyclodextrins (HP-beta-CD) were prepared and compared with control buspirone HCl solution regarding permeability, in vitro duration of mucoadhesion, in vivo nasal clearance in rats and in vitro cytotoxicity on cell culture. Nearly two fold increase in buspirone permeation was observed with 1% chitosan HCl and a 3.5 fold increase with 1% chitosan HCI and 5% HP-beta-CD. Nasal clearance studies showed retention of 50% radioactivity up to about 3.5 h for formulation F7 containing 1% chitosan HCI compared to 1.5 h for control buspirone solution (F1). Results conclusively demonstrated enhancement in permeation with no cytotoxicity. Thus formulations can be used to improve bioavailability of buspirone HCl.