Lan Ke, Jiang Xuehua, He Jianling
West China School of Pharmacy, Sichuan University, 17 Renminnan Road, Chengdu 610041, P.R. China.
Rapid Commun Mass Spectrom. 2007;21(2):112-20. doi: 10.1002/rcm.2814.
A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of quercetin, kaempferol and isorhamnetin in rat plasma. After being treated with beta-glucuronidase and sulfatase, the analytes were extracted by liquid/liquid extraction with the internal standard (IS; baicalein). The chromatographic separation was performed on a Diamonsil C(18) column with a mobile phase consisting of 2% formic acid/methanol (10:90, v/v) at a flow rate of 1.00 mL/min, with a split of 200 microL to the mass spectrometer. Validation results indicated that the lower limit of quantification (LLOQ) was 1 ng . mL(-1). The assay exhibited a linear range of 1-200 ng . mL(-1) and gave a correlation coefficient of 0.9980 or better for each analyte. Quality control samples (1, 5, 20 and 100 ng . mL(-1)) in six replicates from each of three different runs demonstrated an intra-assay precision (RSD) of 1.1-8.9%, an inter-assay precision of 1.6-10.8%, and an overall accuracy (bias) of <13.4%. The extraction recovery of each analyte and internal standard was 70-80%. In the present study, we have investigated the pharmacokinetic profiles of isorhamnetin after oral application in rats equipped with a jugular catheter. After oral dosing of isorhamnetin, the mean values (n = 10) of C(max) were 57.8, 64.8 and 75.2 ng . mL(-1) which were achieved at a T(max) of 8.0, 6.4 and 7.2 h for oral doses of 0.25, 0.5 and 1.0 mg . kg(-1) body weight, respectively. The corresponding mean values for isorhamnetin area under the curver (AUC) from 0 to 60 h were 838.2, 1262.8, 1623.4 ng . h . mL(-1). Our results further demonstrated that the samples analyzed showed isorhamnetin could not be transformed into quercetin or kaempferol in rats, indicating that the demethylation of the 3'-oxymethyl group of isorhamnetin does not occur in Wistar rats.
建立了一种简单灵敏的液相色谱/串联质谱法，并对其进行了验证，用于定量大鼠血浆中的槲皮素、山奈酚和异鼠李素。经β-葡萄糖醛酸酶和硫酸酯酶处理后，采用内标（IS；黄芩苷）液-液萃取法提取分析物。色谱分离在Diamonsil C(18)柱上进行，流动相为2%甲酸/甲醇（10:90，v/v），流速为1.00 mL/min，分流200 μL进入质谱仪。验证结果表明，定量下限（LLOQ）为1 ng·mL(-1)。该测定法的线性范围为1-200 ng·mL(-1)，各分析物的相关系数为0.9980或更高。来自三个不同批次的六个重复的质量控制样品（1、5、20和100 ng·mL(-1)）的批内精密度（RSD）为1.1-8.9%，批间精密度为1.6-10.8%，总体准确度（偏差）<13.4%。各分析物和内标的提取回收率为70-80%。在本研究中，我们研究了在装有颈静脉导管的大鼠口服异鼠李素后的药代动力学特征。口服异鼠李素后，对于0.25、0.5和1.0 mg·kg(-1)体重的口服剂量，C(max)的平均值（n = 10）分别为57.8、64.8和75.2 ng·mL(-1)，在T(max)为8.0、6.4和7.2 h时达到。异鼠李素从0至60 h的曲线下面积（AUC）的相应平均值分别为838.2、1262.8、1623.4 ng·h·mL(-1)。我们的结果进一步表明，所分析的样品显示异鼠李素在大鼠体内不能转化为槲皮素或山奈酚，这表明异鼠李素3'-氧甲基的去甲基化在Wistar大鼠中不会发生。
