Design, evaluation and bioavailability of oxybutynin chloride nanosponges on healthy human volunteers

Abstract

After thirty years, oxybutynin chloride is still the gold first line treatment of nocturnal enuresis. Although oxybutynin chloride is very effective, the drug bioavailability is only 6% as it is subjected to sever first pass effect. The aim of this work is to formulate oxybutynin chloride in a nanosponge formulation to increase the drug bioavailability and maximize its oral benefits. Oxybutynin nanosponges were formulated by emulsion solvent diffusion/salting out method, using ethyl cellulose as a polymer, poly-vinyl alcohol (PVA) as a surfactant and sodium chloride as salting out agent. Oxybutynin chloride loading efficiency was found to exceed 90% (N3 and N4), the drug release from the nanosponge formulations was found to follow Baker and Lonsdale model. Formulae N3 and N4 were compressed in a tablet form and coded TN3 and TN4 respectively to evaluate its bioavailability in comparison to commercially available oxybutynin chloride extended release tablets (Uripan® XR) on 6 healthy human volunteers. The Tmax of both formulae TN3 and TN4 were found to be 2 h while for Uripan® XR it was found to be 4 h, the relative bioavailability of TN3 and TN4 were found to be 213.9% and 248.8% respectively in compression to Uripan® XR.