Chitosan (CS) is a natural biopolymer used frequently in drug delivery because of its biodegradability and biocompatibility. Several derivatives of CS have also been synthesized to improve the mucoadhesion and solubility of the nascent CS. The nano and micro particles are reported to have enhanced drug bioavailability, solubility and permeation. Recently, there is an advancement in the active targeted drug and gene delivery using CS because of its tunable surface modifications. This review focuses on CS and its chemically modified structures along with their different nanostructures with examples from the most exploited routes of administration. Herein, the functionalization of CS nanoparticles has also been enlisted along with the use of CS in the immunotherapy as vaccine carriers. Beside, few patents, ongoing clinical trials and already marketed CS-based products are also enlisted.

壳聚糖 (CS) 是一种天然生物聚合物，因其可生物降解性和生物相容性而经常用于药物递送。还合成了几种 CS 衍生物以改善新生 CS 的粘膜粘附和溶解度。据报道，纳米和微米颗粒具有增强的药物生物利用度、溶解度和渗透性。最近，由于其可调的表面修饰，在使用 CS 的主动靶向药物和基因递送方面取得了进展。本综述重点介绍 CS 及其化学改性结构及其不同的纳米结构，并举例说明了最常用的给药途径。在此，CS 纳米粒子的功能化也与 CS 在免疫治疗中作为疫苗载体的使用一起被纳入。此外，很少有专利，