Local anesthetics have been extensively used in clinical practice to relieve the postoperative pain of patients. However, due to the short half-life of local anesthetics, a simple injection of local anesthetics cannot provide sufficient anesthetic effect for patients. It is important to develop a new delivery system for local drug administration to achieve an extended anesthetic effect without notable side effects. In this study, bupivacaine hydrochloride (BPV) loaded thermosensitive hydroxypropyl chitin (HPCH) based sponges were prepared via a simple solvent-free process for long-lasting drug release. The HPCH sponge showed good mechanical property to resist external stress and maintain the integrity, which was stronger than the collagen/HPCH composite sponge and much better than the pure collagen sponge. The HPCH sponge also displayed good biodegradability and compatibility. The BPV-loaded 2.4%-HPCH (3.6 wt%) sponge showed the most sustained release profile, and the maximal duration of in vitro release was about 8 times longer than that of the control group BPV-loaded 0.8 %-collagen (0.6 wt%) sponge based on commercial Xaracoll. More importantly, the effective duration of blockade (analgesia) of 21.67 h for the BPV-loaded 2.4 %-HPCH (3.6 wt%) sponge was much longer than that of the bupivacaine hydrochloride solution injection (1 h, 0.8 %-BPV solution) in the guinea pig pin-prick test. Hematoxylin-eosin staining data indicated that a very limited mild inflammatory response was observed at the location where the BPV-loaded HPCH (3.6 wt%) sponge was placed. Thus, the HPCH sponge is expected to serve as a promising drug carrier for the sustained release of bupivacaine in postoperative pain management.

局部麻醉剂已广泛用于临床实践，以减轻患者的术后疼痛。但由于局麻药半衰期短，单纯注射局麻药无法为患者提供足够的麻醉效果。重要的是开发一种用于局部给药的新递送系统，以实现延长的麻醉效果而没有明显的副作用。在这项研究中，通过简单的无溶剂工艺制备了负载盐酸布比卡因 (BPV) 的热敏羟丙基甲壳素 (HPCH) 基海绵，以实现长效药物释放。HPCH海绵表现出良好的抗外应力和保持完整性的力学性能，比胶原蛋白/HPCH复合海绵强，远优于纯胶原蛋白海绵。HPCH海绵还表现出良好的生物降解性和相容性。负载 BPV 的 2.4%-HPCH (3.6 wt%) 海绵表现出最持久的释放曲线，体外释放的最大持续时间比对照组负载 BPV 的 0.8%-胶原蛋白 (0.6 wt%) 长约 8 倍%) 基于商业 Xaracoll 的海绵。更重要的是，负载 BPV 的 2.4%-HPCH（3.6 wt%）海绵的有效阻断（镇痛）持续时间为 21.67 小时，远长于盐酸布比卡因溶液注射液（1 小时，0.8%-BPV 溶液）。在豚鼠针刺试验中。苏木精-伊红染色数据表明，在放置 BPV 负载 HPCH (3.6 wt%) 海绵的位置观察到非常有限的轻度炎症反应。因此，