HPLC法测定左旋多巴控释片血药浓度及其药代动力学研究

Determination of Levodopa in Human Plasma by RP- HPLC and the Pharmacokinetics of Aarodopa

目的：建立左旋多巴血药浓度的测定方法并对左旋多巴控释片进行人体药代动力学研究。方法：高效液相色谱法，色谱柱：Ｌｉｃｈｒｏｓｐｈｅｒ １００Ｃ１８柱（５ｕｍ，２５０ｍｍ×４ｍｍ）；流动相：水（含ＥＤＴＡ０．０８ｍｍｏl／L，ＫＨ２ＰＯ４７０ｍｍ７０ｍｍｏｌ／Ｌ，庚烷磺酸钠２．０８ｍｍｏｌ／Ｌ）：甲醇（９０：１０）；流速：１.０ｍｌ／ｍｉｎ；荧光检测：激发波长为２７８ｎｍ，发射波长为３２５ｎｍ；血浆样品用高氯酸沉淀蛋白后直接进样。结果：方法回收率为９５．５０％～１０２．５５％，最低检测限为０．２５ｎｇ，日内ＲＳＤ＜４．２９％（ｎ＝４），日间ＲＳＤ＜６．７３％（ｎ＝４），线性范围为０．１２５～４．０ｕｇ／ｍｌ。８名健康受试者单次口服左旋多巴控释片２５０ｍｇ后，药－时曲线符合二室模型，ＡＵＣ为（２９７．３６±５２.1８）ｕｇ／（ｍｌ·ｍｉｎ），Ｃｍａｘ为（１．０４±０．４２）ｕｇ／ｍｌ，Ｔｍａｘ为（１５２．６５±４６．７１）ｍｉｎ，Ｔ１／２ａ为（１２４．７６±４３．８７）ｍｉｎ，Ｔ１／２β为（１５７．８３±３０．８２）ｍｉｎ．与左旋多巴相比，Ｔｍａｘ和Ｔ１／２ａ具有显著性差异，相对生物利用度为（７０．１７±７．４１）％。

OBJECTIVE: To develop a method for the determination of levodopa in human plasma and study aarodopa's pharmacokinetics. METHODS: Experiments were performed on Waters 2010 HIPLC system with a 474 fluorecence detector (λEX = 278nm, λEm = 325nm) and a Lichrospher 100 C18 column. The mobile phase(pH3. 7) was 90% water containing 0.08 mmol/L EDTA, 70mmol/L KH2PO4, 2. 08mmol/L sodium heptanesulfonate and 10% methanal. The flow rate was 1. 0ml/min. The plasma sample was directly injected for determination after being deproteinized with perchloric acid. RESULTS: The linear range was 0. 125-4.0ug/ml,the limitation of detection was 0. 25ug/ml,within- day RSD<4.29%(n=4),between-day RSD< 6.73% (n = 4), the recoveries of levodopa were 95.50% -102.55%. After oral administration of 250mg aarodopa tablet, the re sults showed that the disposition of aarodopa was conformed to a two-compartment model with T1/2a = (124.76 ± 43.87) min, T1/2β= (157. 83±30. 82)min,Tmax =(152.65±46.71)min,Cmax (1.04±0.42)ug/ml and AUC= (297. 36±52. 18) ug/(ml min) . In comparison with levodopa tablet, Tmax and T1/ 2a were significantly different, the relative biovailability was (70. 1± 7.41) % . CONCLUSION: This method is rapid, accurate and sensitive, it is very suitable for the investigation of clinical phar- macokinetics of levodopa.