In today's biomedical research, a huge effort is being made towards the development of efficient drug delivery systems, achieving sustainable and controlled delivery of drugs. Chitosan (CS) hydrogels are high water content materials with very relevant biological properties to that purpose. Their use for a local and delayed delivery has already been demonstrated for a wide variety of therapeutic agents. One relatively recent strategy to improve these CS-based systems consists in the insertion of colloids, embedding drugs, within their three-dimensional matrix. This provides a second barrier to the diffusion of drugs through the system, and allows to better control their release. The main objective of this review is to report the many existing complex systems composed of CS hydrogels embedding different types of colloids used as drug delivery devices to delay the release of drugs. The various biomedical applications of such final systems are also detailed in this review.

在当今的生物医学研究中，人们正在努力开发高效的药物输送系统，以实现药物的可持续和可控输送。壳聚糖 (CS) 水凝胶是高含水量材料，具有与该目的非常相关的生物学特性。它们用于局部和延迟递送已经被证明可用于多种治疗剂。一种相对较新的改进这些基于 CS 的系统的策略包括在其三维矩阵中插入胶体、嵌入药物。这为药物通过系统的扩散提供了第二道屏障，并允许更好地控制它们的释放。本综述的主要目的是报告由嵌入不同类型胶体的 CS 水凝胶组成的许多现有复杂系统，这些胶体用作药物输送装置以延迟药物的释放。这种最终系统的各种生物医学应用也在本综述中进行了详细介绍。