This study reports a physicochemical stability evaluation of a previously reported liposomal prilocaine (PLCLUV) formulation () before and after steam sterilization as well as its local toxicity evaluation. Prilocaine (PLC) was encapsulated into extruded unilamellar liposomes (LUVs) composed by egg phosphatidylcholine:cholesterol:alfa-tocopherol (4:3:0.07, mole %). Laser light-scattering analysis (p > 0.05) and thiobarbituric acid reaction (p > 0.05) were used to evaluate the liposomes physical (size) and chemical (oxidation) stability, respectively. The prilocaine chemical stability was followed by 1H-nuclear magnetic resonance. These tests detected no differences on the physicochemical stability of PLC or PLCLUV, sterilized or not, up to 30 days after preparation (p > 0.05). Finally, the paw edema test and histological analysis of rat oral mucosa were used to assess the possible inflammatory effects of PLCLUV. PLCLUV did not evoke rat paw edema (p > 0.05), and no significant differences were found in histological analysis, when compared to the control groups (p > 0.05). The present work shows that PLCLUV is stable for a 30-day period and did not induce significant inflammatory effects both in the paw edema test and in histological analysis, giving supporting evidence for its safety and possible clinical use in dentistry.

中文翻译：

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脂质体丙胺卡因制剂的稳定性和局部毒性评估

本研究报告了先前报道的脂质体丙胺卡因 (PLCLUV) 制剂 () 在蒸汽灭菌前后的物理化学稳定性评估及其局部毒性评估。丙胺卡因 (PLC) 被封装到由卵磷脂:胆固醇:α-生育酚 (4:3:0.07, 摩尔 %) 组成的挤出单层脂质体 (LUV) 中。激光散射分析（p > 0.05）和硫代巴比妥酸反应（p > 0.05）分别用于评估脂质体的物理（大小）和化学（氧化）稳定性。丙胺卡因化学稳定性由 1 H-核磁共振跟踪。这些测试未检测到 PLC 或 PLCLUV（无论是否灭菌）的物理化学稳定性在制备后长达 30 天的差异（p > 0.05）。最后，爪水肿试验和大鼠口腔黏膜组织学分析用于评估 PLCLUV 可能的炎症作用。PLCLUV 不会引起大鼠爪水肿（p > 0.05），并且与对照组相比，在组织学分析中没有发现显着差异（p > 0.05）。目前的工作表明 PLCLUV 在 30 天内是稳定的，并且在爪水肿试验和组织学分析中都没有引起显着的炎症作用，为其安全性和可能的​​牙科临床应用提供了支持证据。