左旋多巴与2,3-二氯-5,6-二氰-1,4-苯醌的荷移反应研究

Study on the charge-transfer complex of levodopa with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone by spectrophotometry

研究了左旋多巴和2，3-二氯-5，6-二氰-1，4-苯醌（DDBQ）的反应条件，确定在硼砂溶液中，在60℃反应70min可获得稳定的络合物，其λmax=346nm，组成比为1：1，表观摩尔吸收系数ε=1．1×10^4L·mol^-1·cm^-1，应用拟定的方法测定药物制剂测定结果与文献方法一致，回收率在97．25％～102．7％之间，相对标准偏差在0．7％以内。

A spectrophotometric method has been established for the determination of levodopa. It is based on the charge transfer reaction of levodopa with 2,3-dichloro-5,6-dicyano- 1,4-benzoquinone （DDBQ） in borax buffer solution. The apparent molar absorptivity of the complex was found to be 1.1×10^4 L·mol^-1· cm^-1 at 346 nm. The calibration curve is linear in the concentration range of 0.5 - 15.5μg/mL. The composition of complex of levodopa with DDBQ is 1：1. Recoveries are in the range of 97.25 % - 102.7 %. The relative standard deviations are in the range of 0.62 - 0.70 %. This method has been applied to the determination of levodopa in tablets with satisfactory results.