Conventional systematically-administered drugs distribute evenly throughout the body, get degraded and excreted rapidly while crossing many biological barriers, leaving minimum amounts of the drugs at pathological sites. Controlled drug delivery aims to deliver drugs to the target sites at desired rates and time, thus enhancing the drug efficacy, pharmacokinetics, and bioavailability while maintaining minimal side effects. Due to a number of unique advantages of the recent microfluidic lab-on-a-chip technology, microfluidic lab-on-a-chip has provided unprecedented opportunities for controlled drug delivery. Drugs can be efficiently delivered to the target sites at desired rates in a well-controlled manner by microfluidic platforms via integration, implantation, localization, automation, and precise control of various microdevice parameters. These features accordingly make reproducible, on-demand, and tunable drug delivery become feasible. On-demand self-tuning dynamic drug delivery systems have shown great potential for personalized drug delivery. This review presents an overview of recent advances in controlled drug delivery using microfluidic platforms. The review first briefly introduces microfabrication techniques of microfluidic platforms, followed by detailed descriptions of numerous microfluidic drug delivery systems that have significantly advanced the field of controlled drug delivery. Those microfluidic systems can be separated into four major categories, namely drug carrier-free micro-reservoir-based drug delivery systems, highly integrated carrier-free microfluidic lab-on-a-chip systems, drug carrier-integrated microfluidic systems, and microneedles. Microneedles can be further categorized into five different types, i.e. solid, porous, hollow, coated, and biodegradable microneedles, for controlled transdermal drug delivery. At the end, we discuss current limitations and future prospects of microfluidic platforms for controlled drug delivery.

传统的系统给药药物均匀分布在全身，在跨越许多生物屏障的同时迅速降解和排泄，在病理部位留下最少量的药物。受控药物递送旨在以期望的速率和时间将药物递送至靶位点，从而提高药物疗效、药代动力学和生物利用度，同时保持最小的副作用。由于最近微流控芯片实验室技术的许多独特优势，微流控芯片实验室为受控药物输送提供了前所未有的机会。微流控平台通过集成、植入、定位、自动化和各种微器件参数的精确控制，可以以良好控制的方式将药物以所需的速率有效地递送到靶位点。这些特征相应地使得可重复的、按需的和可调节的药物输送变得可行。按需自调节动态药物输送系统已显示出个性化药物输送的巨大潜力。本综述概述了使用微流体平台控制药物输送的最新进展。该综述首先简要介绍了微流控平台的微加工技术，然后详细描述了众多显着推进了受控药物输送领域的微流控药物输送系统。这些微流控系统可分为四大类，即无载药微库给药系统、高度集成的无载流控芯片实验室系统、载药集成微流控系统和微针。微针可以进一步分为五种不同类型，即 实心、多孔、空心、涂层和可生物降解的微针，用于受控透皮药物输送。最后，我们讨论了用于受控药物输送的微流体平台的当前局限性和未来前景。