Different methods have been used for CYP3A phenotyping, such as probe drugs or the urinary index 6β-hydroxycortisol/cortisol ratio (6β-OHF:C). This work describes a simple and affordable method for the simultaneous determination of the endogenous compounds cortisol and 6β-hydroxycortisol in urine using a background subtraction approach. The method was applied to investigate the CYP3A activity in HIV-infected pregnant women (n = 9) in the third trimester and postpartum periods. Also, the within-day variability in the 6β-OHF:C index was also evaluated. The sample preparation consists of a pre-cleanup with acetonitrile followed by liquid-liquid extraction with ethyl acetate. The analytes were resolved by employing an Acquity UPLC®BEH C18 column with a mobile phase that consisted of a mixture of acetonitrile containing 0.1% formic acid and 0.1% formic acid in gradient mode. The method presented linearities of 1-1.000 ng/mL and 2-1.000 ng/mL for C and 6β-OHF, respectively, and presented acceptable precision and accuracy. Qualitative and quantitative matrix effects tests were also performed. A high 6β-OHF:C within-day variability was observed in both phases. In the third trimester period, the 6β-OHF:C ranged from 2.57 to 51.69, with a mean ± standard deviation (SD) of 15.12 ± 5.41 (n = 9). Similar values were obtained in the postpartum period, with 6β-OHF:C ranging from 3.48 to 44.54 with a mean ± SD of 14.37 ± 5.73 (n = 7). Even though the 6β-OHF:C is a non-invasive index for CYP3A phenotyping, its use is susceptible to high within-day variability.

中文翻译：

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通过UPLC-MS / MS测定尿液中内源性皮质醇和6β-羟基皮质醇的背景扣除方法，并用于HIV感染孕妇的日间变异性研究。

CYP3A表型已使用了不同的方法，例如探针药物或尿指标6β-羟基皮质醇/皮质醇比率（6β-OHF：C）。这项工作描述了一种简单且价格合理的方法，可使用背景扣除法同时测定尿液中的内源性化合物皮质醇和6β-羟基皮质醇。该方法用于研究妊娠中期和产后HIV感染孕妇（n = 9）的CYP3A活性。此外，还评估了6β-OHF：C指数的日内变化。样品制备包括用乙腈进行预净化，然后用乙酸乙酯进行液-液萃取。通过使用带有流动相的AcquityUPLC®BEH C18色谱柱来分离分析物，该色谱柱由含有0.1％甲酸和0的乙腈的混合物组成。梯度模式下为1％甲酸。该方法对C和6β-OHF的线性分别为1-1.000 ng / mL和2-1.000 ng / mL，并具有可接受的精度和准确性。还进行了定性和定量的基质效应测试。在两个阶段中均观察到6β-OHF：C的日内高变异性。在孕晚期，6β-OHF：C范围从2.57到51.69，平均±标准差（SD）为15.12±5.41（n = 9）。产后时期获得了相似的值，6β-OHF：C在3.48到44.54之间，平均值±SD为14.37±5.73（n = 7）。即使6β-OHF：C是CYP3A表型的非侵入性指标，其使用也容易受到日内高变异性的影响。并给出了可接受的精度和准确性。还进行了定性和定量的基质效应测试。在两个阶段均观察到6β-OHF：C的日内高变异性。在孕晚期，6β-OHF：C范围从2.57到51.69，平均±标准差（SD）为15.12±5.41（n = 9）。在产后期间获得了相似的值，6β-OHF：C在3.48到44.54之间，平均值±SD为14.37±5.73（n = 7）。即使6β-OHF：C是CYP3A表型的非侵入性指标，其使用也容易受到日内高变异性的影响。并给出了可接受的精度和准确性。还进行了定性和定量的基质效应测试。在两个阶段均观察到6β-OHF：C的日内高变异性。在孕晚期，6β-OHF：C范围从2.57到51.69，平均±标准差（SD）为15.12±5.41（n = 9）。产后时期获得了相似的值，6β-OHF：C在3.48到44.54之间，平均值±SD为14.37±5.73（n = 7）。即使6β-OHF：C是CYP3A表型的非侵入性指标，其使用也容易受到日内高变异性的影响。平均±标准差（SD）为15.12±5.41（n = 9）。产后时期获得了相似的值，6β-OHF：C在3.48到44.54之间，平均值±SD为14.37±5.73（n = 7）。即使6β-OHF：C是CYP3A表型的非侵入性指标，其使用也容易受到日内高变异性的影响。平均±标准差（SD）为15.12±5.41（n = 9）。在产后期间获得了相似的值，6β-OHF：C在3.48到44.54之间，平均值±SD为14.37±5.73（n = 7）。即使6β-OHF：C是CYP3A表型的非侵入性指标，其使用也容易受到日内高变异性的影响。