Biodegradable polymers in drug delivery and oral vaccination

Abstract

Over the years biodegradable polymers have emerged as promising polymeric materials in drug delivery and vaccination due to their fascinating properties like biocompatibility, biodegradability, and minimal toxicity. Poor bioavailability is still the major issue for numerous drugs and vaccines delivered through oral route owing to their low solubility, degradation by acidic environment of stomach or by proteolytic enzymes of gastrointestinal tract (GIT). Concepts of oral vaccine delivery targeting mucosal immune system in particulate carriers could give desired immunological response for longer period without any booster doses and thus mitigate the need of repetitive injection and skilled personnel as required in parenteral vaccination. These particulate systems can also protect drugs or proteinaceous antigens from acidic environment or proteolytic enzymes of GIT. In this review the current applications and future scopes of biodegradable polymers like chitosan, alginate, poly (lactic acid-co-glycolic acid), etc., in the development of nontoxic and effective oral carrier systems have been discussed. The improvement in bioavailability of curcumin through encapsulation in polymeric microparticles and immunogenicity of natural antigen as cell envelope proteins (CEPs) upon encapsulation in chitosan microparticles for cholera infection has also been discussed. Similar types of strategies for oral vaccination have also been utilized in the treatment of other infectious diseases. Thus, in nutshell, biodegradable polymers can evolve as an important tool to develop suitable delivery systems in drug delivery and oral vaccination strategies. Further, the review also highlights the loading of drug/vaccine components and subsequently, their release mechanisms from the particulate carrier system.