Chitosan modified by organo-functionalities as an efficient nanoplatform for anti-cancer drug delivery process

Abstract

Cancer, one of the lethal threats to human health, is most frequently treated with surgery, chemotherapy and radiation. Specific receptors and abnormal physiochemical conditions around the tumor microenvironment [abnormal pH, the redox environment and higher temperature] play an important role in controlling cancer cells to achieve effective delivery of anti-cancer drugs. Recently, targeted nanoparticles (NPs) are rapidly being developed to resolve the problems associated with the delivery of anti-cancer drugs which include their poor solubility, non-specific distribution, high toxicity and poor stability. Amongst the various natural polymers studied, chitosan (CS), the first derivative of chitin is one of the polymers which has received most attention as carrier (nanoplatform) for targeted delivery of various anti-cancer drugs to the tumor cells due to its good biocompatibility, low toxicity, responsiveness to environmental factors, high loading capacity and most importantly, active functional groups for chemical modifications. The present review aims to describe CS based nanoplatform by the diverse organic modifications made on CS skeleton by covalent bond, including hydrophobic and hydrophilic groups, stimuli-responsive (pH, redox and thermo) targeting systems and targeting ligands (small molecules, peptides, protein/antibodies, aptamers, hyaluronic acid (HA)) for enhancing its various properties associated with anti-cancer drug delivery process.