Hydrogels are water-swollen three-dimensional networks made of polymers, proteins, small molecules or colloids. They constitute a versatile platform for drug delivery because of their capacity to encapsulate and protect drugs and provide sustained and/or remotely programmable spatial and temporal release and have thus generated a substantial amount of research for the delivery of either small active compounds or biopharmaceuticals. This article discusses the features that make hydrogels attractive as matrices for delivery and reviews a range of designs, focussing on studies from recent years, in particular: ‘smart’ hydrogels (responding to temperature, light, magnetic fields, ultrasounds or combined stimuli); recent technologies: 3D printing and microneedles; and closes by discussing polymer-free drug delivery systems: peptides, small molecules and colloids.

水凝胶是由聚合物，蛋白质，小分子或胶体制成的水溶胀的三维网络。它们具有封装和保护药物的能力，并提供持续和/或可远程编程的空间和时间释放，因此构成了用于药物输送的通用平台，因此已经为输送小型活性化合物或生物药物进行了大量研究。本文讨论了使水凝胶作为传递基质具有吸引力的特性，并回顾了一系列设计，重点是近年来的研究，尤其是：“智能”水凝胶（响应温度，光，磁场，超声或组合刺激）；最新技术：3D打印和微针；最后讨论无聚合物的药物输送系统：肽，