Aqueous local anaesthetic solution, method for improving solubility of local anaesthetic, local anaesthetic agent with decreased neurotoxicity and method for decreasing neurotoxicity of local anaesthetic agent

摘要

An aqueous local anesthetic solution having a pH of 6.5-8.5, which contains a local anesthetic included in cyclodextrin or a derivative thereof in a concentration of the local anesthetic of not less than 0.02%, a method for improving solubility of local anesthetic in water at a pH of 6.5-8.5, comprising including the local anesthetic in cyclodextrin or a derivative thereof, a local anesthetic agent comprising an inclusion compound of local anesthetic in cyclodextrin or a derivative thereof, a method for decreasing neurotoxicity of local anesthetic agent, comprising including the local anesthetic in cyclodextrin or a derivative thereof, and an inclusion compound of local anesthetic in cyclodextrin or a derivative thereof. The local anesthetic agent and aqueous local anesthetic solution of the present invention have decreased neurotoxicity, so that the duration of anesthesia can be controlled clinically safely by reducing/increasing its concentration or dose. In particular, the aqueous local anesthetic solution can be used at a pH near that of a living body. Thus, it can be used even when living tissue has an acidic pH. Moreover, the pain caused by local acidosis at an injection site by a conventional local anesthetic dissolved in an acidic solution can be reduced.