Chitosan-based spray-dried mucoadhesive microspheres for sustained oromucosal drug delivery

Abstract

The main issues attracting substantial consideration when delivering drugs to the oromucosa include the enhancement of mucoadhesion of drug formulations in order to elongate their residence time on the site of delivery and the sustained release of drug from the formulations following deposition. In this study, the mucoadhesive biopolymers of chitosan and its derivatives, including high molecular weight, low molecular weight, and carboxylic derivative, were employed as the excipients to prepare spray-dried microspheres for the oromucosal drug (e.g. benzydamine hydrochloride, BZH) delivery with the aim to enhance the delivery efficiency. All chitosan-modified spray-dried powders showed the size <10μm with greater surface roughness, moisture content <10% w/w, and improved flowability. The addition of chitosan in the formulations can tremendously extend the duration of drug release. More importantly, the mucoadhesive interaction of chitosan-modified microparticles was strongly enhanced, and it can be further improved as the augmentation of chitosan contents in the formulations. Our data clearly demonstrate that the inclusion of chitosan in spray-dried microspheres elongates the duration of drug release and also enhance the mucoadhesive interaction force of microspheres to the mucosal membrane, which may be of benefit in the treatment of local conditions.