Haynes D H, Kirkpatrick A F
Department of Pharmacology, University of Miami, School of Medicine, Florida.
Reg Anesth. 1991 May-Jun;16(3):173-80.
Lecithin-coated microdroplets of methoxyflurane (MOF) have been reported to produce local anesthesia of long duration in rats. The present study was conducted in two phases. The first phase was open label studies in two human volunteers aimed at determining the effective concentration of MOF in human skin. Over the concentration range of 0.3-2.4%, MOF produced local anesthesia to pinprick and cold stimuli within 15 seconds. The duration of the anesthesia effect of 2.4% MOF in the skin of the buttock, forearm and leg was five to eight days. Microdroplets containing isoflurane, a more volatile agent, gave an anesthetic effect that reversed within two to five hours. In the second phase of the study, the safety and efficacy of MOF were compared to phenol in placebo-controlled and blinded studies using indwelling stimulating electrodes. Phenol was destructive to skin at a concentration necessary to obtain a degree of local anesthesia comparable to MOF. The greater part of the anesthetic effect produced by phenol at this "toxic" concentration was transient (approximately one hour). In contrast to phenol, MOF produced an anesthetic effect lasting four to seven days without producing visible damage to skin. These results suggest that MOF is safer and more efficacious than phenol for producing long-lasting local anesthesia of human skin.
据报道，卵磷脂包裹的甲氧氟烷（MOF）微滴可在大鼠中产生长时间的局部麻醉作用。本研究分两个阶段进行。第一阶段是在两名人类志愿者中开展的开放标签研究，旨在确定MOF在人体皮肤中的有效浓度。在0.3%-2.4%的浓度范围内，MOF可在15秒内对针刺和冷刺激产生局部麻醉作用。2.4%的MOF在臀部、前臂和腿部皮肤产生的麻醉效果持续五至八天。含有更易挥发的异氟烷的微滴产生的麻醉效果在两至五小时内逆转。在研究的第二阶段，在使用植入式刺激电极的安慰剂对照和盲法研究中，将MOF的安全性和有效性与苯酚进行了比较。在获得与MOF相当的局部麻醉程度所需的浓度下，苯酚对皮肤具有破坏性。苯酚在这种“毒性”浓度下产生的大部分麻醉效果是短暂的（约一小时）。与苯酚不同，MOF产生的麻醉效果持续四至七天，且不会对皮肤造成明显损伤。这些结果表明，在产生人体皮肤长效局部麻醉方面，MOF比苯酚更安全、更有效。
