Tumor targeting strategies for chitosan-based nanoparticles.

Currently, targeted nanoparticles (NPs) are rapidly being developed to overcome various bottlenecks of antitumor agents, such as poor solubility in aqueous solution, poor pharmacokinetics, a lack of selectivity and undesirable side effects in healthy tissues. In recent years, chitosan, a cationic polysaccharide, has been widely explored for the targeted delivery of antitumor agents due to its unique physicochemical and biological properties, such as biocompatibility, biodegradability, mucoadhesive feature, absorption enhancement and active functional groups for chemical modifications. This article reviews the recent developments in various target-specific nanoparticles based on chitosan and its derivatives, including passive, active and stimuli-sensitive targeting strategies. In addition, the target mechanisms and the key efficacy factors are illuminated.