Chitosan mediated smart photodynamic therapy based novel drug delivery systems- a futuristic view

In order to improve the pharmacological and therapeutic properties of drugs, researchers have attempted numerous novel approaches, such as stimuli-responsive systems, and targeted drug delivery systems. These systems can be attempted by nano -based drug delivery systems involving biocompatible polymers. One among which is chitosan, a linear polysaccharide, a promising potential polymer that gained interest in delivering challenging drugs. Chitosan can encapsulate and release the drugs in a controlled/sustained manner. Chitosan can be used to develop a variety of drug delivery carriers, including films, gels, nanoparticles, nanodispersions, nanomicelles, and patches. In this regimen, minimally invasive photodynamic therapy has recently gained much interest in treating vascular diseases, including cancer, ocular diseases, microbial infections, skin disorders, etc. Photodynamic therapy utilizes light excited at a specific wavelength, eliciting singlet oxygen production. Selflighting photodynamic therapy and combination-based photodynamic therapy also offer synergistic effects. Photodynamic therapy is more selective and specific, which may offer treatment for deep-seated diseased tissues compared to conventional therapeutic modalities. Light-activated novel drug delivery formulations have been reported using various biocompatible polymers, including chitosan. Chitosan offers its effectiveness as mucoadhesiveness, tissue penetrability, antioxidant, antimicrobial properties, supports in singlet oxygen generation, and shown its benefits in photodynamic therapy. Therefore, this review presents numerous applications of chitosan-based light-activated drug delivery systems with particular emphasis on their patents and clinical trials. The literature has been collected and compiled using various search resources such as Science Direct, JGate, Google Scholar, PubMed, and research data.