Mahmood I, Neau S H, Mason W D
School of Pharmacy, University of Missouri-Kansas City 64110-2499.
J Pharm Biomed Anal. 1994 Jul;12(7):895-9. doi: 10.1016/0731-7085(93)e0021-e.
A sensitive fluorimetric assay based on inhibition of rat brain monoamine oxidase-B (MAO-B) in vitro has been described. The procedure measures the inhibition of MAO activity produced by the addition of selegiline extracted from human plasma. This method uses the substrate kynuramine which is converted by MAO to the product 4-hydroxyquinoline which fluoresces in alkaline solution. Human plasma (500 microliters) containing different concentrations of selegiline was deproteinized and extracted with ethyl acetate-butyl chloride. After reconstitution with 200 microliters phosphate buffer, 50 microliters of rat brain homogenate was added to study the MAO-B inhibition. Selegiline metabolites, amphetamine and methamphetamine (50 ng ml-1), and desmethylselegiline (20 ng ml-1), showed no inhibitory effect on MAO-B inhibition. Selegiline concentrations as low as 0.25 ng ml-1 can be detected. The standard curve was linear from 125 pg (0.25 ng ml-1) to 4000 pg (8.0 ng ml-1) in the incubation tube. This method should be helpful to determine pharmacokinetic parameters of selegiline after i.v. or oral dosing.
已描述了一种基于体外抑制大鼠脑单胺氧化酶-B（MAO-B）的灵敏荧光测定法。该程序测量加入从人血浆中提取的司来吉兰所产生的MAO活性抑制作用。此方法使用底物犬尿胺，其被MAO转化为在碱性溶液中发荧光的产物4-羟基喹啉。将含有不同浓度司来吉兰的人血浆（500微升）进行脱蛋白处理，并用乙酸乙酯-丁基氯萃取。用200微升磷酸盐缓冲液复溶后，加入50微升大鼠脑匀浆以研究MAO-B抑制作用。司来吉兰代谢产物、苯丙胺和甲基苯丙胺（50纳克/毫升）以及去甲基司来吉兰（20纳克/毫升）对MAO-B抑制作用无抑制效果。可检测到低至0.25纳克/毫升的司来吉兰浓度。在孵育管中，标准曲线在125皮克（0.25纳克/毫升）至4000皮克（8.0纳克/毫升）范围内呈线性。该方法应有助于确定静脉注射或口服给药后司来吉兰的药代动力学参数。
