Heparin, a sulfate-containing linear polysaccharide, has proven preclinical and clinical efficacy for a variety of disorders. Heparin, including unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), and ultra-low-molecular-weight heparin (ULMWH), is administered systematically, in the form of a solution in the clinic. However, it is eliminated quickly, due to its short half-life, especially in the case of UFH and LMWH. Frequent administration is required to ensure its therapeutic efficacy, leading to poor patient compliance. Moreover, heparin is used to coat blood-contacting medical devices to avoid thrombosis through physical interaction. However, the short-term durability of heparin on the surface of the stent limits its further application. Various advanced sustained-release strategies have been used to prolong its half-life in vivo as preparation technologies have improved. Herein, we briefly introduce the pharmacological activity and mechanisms of action of heparin. In addition, the strategies for sustained release of heparin are comprehensively summarized.

肝素是一种含硫酸盐的线性多糖，已被证明对多种疾病具有临床前和临床疗效。肝素，包括普通肝素 (UFH)、低分子肝素 (LMWH) 和超低分子肝素 (ULMWH)，在临床以溶液的形式系统给药。然而，由于其半衰期短，它被迅速消除，特别是在 UFH 和 LMWH 的情况下。需要频繁给药以确保其治疗效果，导致患者依从性差。此外，肝素被用于涂敷与血液接触的医疗器械，以避免通过物理相互作用形成血栓。然而，肝素在支架表面的短期耐久性限制了其进一步的应用。随着制备技术的改进，各种先进的缓释策略已被用于延长其体内半衰期。在此，我们简要介绍肝素的药理活性和作用机制。此外，对肝素缓释策略进行了全面总结。