Chitosan-based drug delivery system for a new chemical entity for photodynamic wound therapy

Abstract

Due to inappropriate or excessive use of antibiotics, multi resistance has become a global problem which threatens the public health. Photodynamic therapy has emerged as a promising and important approach in many fields of drug therapy. In recent years, many studies on photodynamic therapy for infections have shown promising results. One of the advantages of using PDT in treatment of infections is the mechanism of drug action which differs from that of antibiotics. This opens the door for the possibilities of treating multidrug resistant bacteria. PDT requires photosensitizer (PS), which are stable, nontoxic and effective. To improve the delivery of PS usually a delivery system which provides better stability and control of the PS. Polymer-based nanoparticles have been proposed as a suitable delivery system based on their advantages (e.g. biodegradable, less toxicity, microbial and hemostatic properties). A New Chemical Entity (NCE) recently developed and patented by Photocure ASA is expected to exhibit superior antimicrobial properties and improved wound healing. Chitosan lecithin nanoparticles were selected and developed as a carrier system for this new entity. At this stage of development, the delivery system was found to have many stability issues which need to be optimized in the future. The sizes of the carrier were found to be suitable but their entrapment efficiency was found to be rather low (less than 22 %).