Prado Andressa R, Yokaichiya Fabiano, Franco Margareth Kazuyo Kobayashi Dias, Silva Camila Morais Gonçalves da, Oliveira-Nascimento Laura, Franz-Montan Michelle, Volpato Maria C, Cabeça Luís F, de Paula Eneida
Biochemistry and Tissue Biology Department, Biology Institute, University of Campinas (Unicamp), Campinas, SP, Brazil.
Department Quantum Phenomena in Novel Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
J Pharm Pharmacol. 2017 Jun;69(6):652-662. doi: 10.1111/jphp.12703. Epub 2017 Feb 17.
Oxethazaine (OXZ) is one of the few local anaesthetics that provides analgesia at low pH, but presents poor solubility, cytotoxicity and no parenteral formulations. To address these issues, we aimed to prepare OXZ host-guest inclusion complex with hydroxypropyl-beta-cyclodextrin (HP-β-CD).
The inclusion complex was formed by co-solubilization, followed by a job plot analysis to determine stoichiometry of complexation and dialysis equilibrium analysis (based on UV/VIS absorption and fluorescence profiles of OXZ). Complex formation was confirmed by phase-solubility data, X-ray, Scanning Electron Microscopy and DOSY- H-NMR experiments. In vitro cytotoxicity was analysed by MTT test in 3T3 fibroblasts. In vivo analgesia was tested by Von Frey test (inflammatory wounds - rats).
Oxethazaine complexed (1 : 1 molar ratio) with HP-β-CD, as indicated by loss of OZX crystalline structure (X-ray) and strong host: guest interaction (NMR, K = 198/M), besides increased solubility. In vitro cell survival improved with the complex (IC OXZ = 28.9 μm, OXZ : HP-β-CD = 57.8 μm). In addition, the complex (0.1% OXZ) promoted in vivo analgesia for the same time that 2% lidocaine/epinephrine did.
Our results show that complexation improved physicochemical and biological properties of OXZ, allowing its application to inflamed tissues by parenteral routes.
奥昔卡因（OXZ）是少数几种在低pH值下能提供镇痛作用的局部麻醉剂之一，但存在溶解度差、细胞毒性且无肠胃外制剂的问题。为解决这些问题，我们旨在制备奥昔卡因与羟丙基-β-环糊精（HP-β-CD）的主客体包合物。
通过共溶解形成包合物，随后进行工作曲线分析以确定络合化学计量比，并进行透析平衡分析（基于奥昔卡因的紫外/可见吸收和荧光光谱）。通过相溶解度数据、X射线、扫描电子显微镜和扩散排序光谱法-氢核磁共振实验确认包合物的形成。通过MTT试验在3T3成纤维细胞中分析体外细胞毒性。通过von Frey试验（炎症伤口-大鼠）测试体内镇痛效果。
奥昔卡因与HP-β-CD以1:1摩尔比络合，这由奥昔卡因晶体结构的丧失（X射线）和强烈的主客体相互作用（核磁共振，K = 198/M）表明，此外溶解度增加。复合物使体外细胞存活率提高（奥昔卡因的半数抑制浓度 = 28.9 μM，奥昔卡因:HP-β-CD = 57.8 μM）。此外，复合物（0.1%奥昔卡因）在体内产生的镇痛效果与2%利多卡因/肾上腺素相同。
我们的结果表明，络合改善了奥昔卡因的物理化学和生物学性质，使其能够通过肠胃外途径应用于炎症组织。
