State Key Laboratory of Biochemical Engineering, PLA Key Laboratory of Biopharmaceutical Production & Formulation Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China.
Yichang Humanwell Pharmaceutical Co., Ltd., Yichang 443008, P. R. China.
J Mater Chem B. 2020 Aug 5;8(30):6322-6332. doi: 10.1039/d0tb01129k.
Local anesthetic drugs are widely used in postoperative analgesia, local nerve block in surgery, and in the therapy of chronic pain. Due to their short half-time, a single administration of local anesthetics merely maintains the nerve block for several hours, which cannot meet the long-term analgesia effect needed in clinical treatment. In order to break through this limitation of local anesthetics, research work regarding controlled drug release from microspheres has attracted broad and current interest. This review introduces the recent research and development in local anesthetic-loaded microspheres for future clinical applications, where for an efficient microsphere formulation, the most critical aspects are an optimum preparation method, a high loading efficiency, and an ideal release rate. This review first summarizes the recent preparation methods of local anesthetic-loaded microspheres, which includes emulsion-solvent evaporation, spray-drying, microfluidic droplets, and premix membrane emulsification technology. Next, strategies for increasing the loading efficiency of the drug in microspheres are reviewed based on the solidification conditions, polymer properties, microsphere formulation, including the external water phase, pH, and polymer concentration. Finally, the effects of the preparation conditions, material characteristics, particle characteristics, and hydrogel/microsphere composite systems on the controlled release behavior are summarized.
局部麻醉药物在术后镇痛、手术局部神经阻滞和慢性疼痛治疗中被广泛应用。由于其半衰期短，单次给予局部麻醉药仅能维持数小时的神经阻滞，无法满足临床治疗所需的长期镇痛效果。为了突破局部麻醉药的这一局限性，研究人员对于从微球中控制药物释放的工作引起了广泛关注。本文综述了局部麻醉药负载微球的最新研究进展，以期在未来的临床应用中得到应用。对于高效的微球制剂，最关键的方面是最佳的制备方法、高载药量和理想的释放速率。本文首先总结了局部麻醉药负载微球的最新制备方法，包括乳液-溶剂蒸发、喷雾干燥、微流控液滴和预混膜乳化技术。其次，基于固化条件、聚合物性质、微球配方（包括外水相、pH 值和聚合物浓度）综述了提高微球中药物载药量的策略。最后，总结了制备条件、材料特性、颗粒特性以及水凝胶/微球复合体系对控制释放行为的影响。
