• Qiuwen Li, Shouyu Xu, Yangwen Ou, Lianbang Zhou, Furong Huang, Wanwei Jiang, Haihui Xie, Xiaohua Zou, Jihua Gao, Shu''an Jin, Hongmei Zhou, Yanjuan Huang, Zhihao Pan, Juying Liu, Guyan Wang, Xiangkui Li, CanLin Sun, Ling Zhao, Lin Li, Qin Liu, Kaiming Duan, and Saiying Wang.
• The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, People's Republic of China.
• J Clin Anesth. 2024 Jun 27; 97: 111524111524.

Study ObjectiveHR18034, composed of the ropivacaine encapsulated in multi-lamellar, concentric circular structure liposomes as the major component and a small amount of free ropivacaine, has performed well in animal experiments and phase I clinical trials. This trial was to investigate the efficacy, safety, pharmacokinetic profile and the minimum effective dose of HR18034 for postoperative analgesia after hemorrhoidectomy compared with ropivacaine.DesignA multicenter, randomized, double-blind trial.Setting19 medical centers in China.Patients85 patients undergoing hemorrhoidectomy between October 2022 to November 2022.InterventionsPatients were randomly divided into HR 18034 190 mg group, 285 mg group, 380 mg group and ropivacaine 75 mg group, receiving single local anesthetic perianal injection for postoperative analgesia.MeasurementsThe primary outcome was the area under the resting state NRS score -time curve within 72 h after injection. The second outcomes included the proportion of patients without pain, the proportion of patients not requiring rescue analgesia, cumulative morphine consumption for rescue analgesia, etc. Safety was evaluated by adverse events incidence and plasma ropivacaine concentrations were measured to explore the pharmacokinetic characteristics of HR18034.Main ResultsThe areas under the NRS score (at rest and moving states)-time curve were significantly lower in HR 18034 380 mg group than ropivacaine 75 mg at 24 h, 48 h, and 72 h after administration. However, this superiority was not observed in HR18034 190 mg group and 285 mg group. There was no difference in cumulative morphine consumption for rescue analgesia between HR 18034 groups and ropivacaine group.ConclusionsHR 18034 380 mg showed superior analgesic efficacy and equivalent safety compared to ropivacaine 75 mg after hemorrhoidectomy, thus preliminarily determined as minimum effective dose.Copyright © 2023. Published by Elsevier Inc.

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