ИСТИНА

Purpose. Development and validation of methods for determining plasma concentrations of etonogestrel (3-keto desogestrel). The method used - HPLC/MS. Analytical equipment - liquid chromatograph and a mass spectrometer with a triple quadrupole. Chromatographic conditions: analytical column C18 (75*2,1 mm, 3.5 µm), flow rate 0.4 ml/min, eluting with a gradient system (acetonitrile:water). Detection mode is MRM. Sample preparation is a liquidliquid extraction with diethyl ether was concentrated and redissolved in 50% acetonitrile. Results. The recovery rate is 77%. Calibration curve is linear in the range 40-4000 pg/ml. The LLOQ is 40 pg/ml and LOD is 20 pg/ml. Conclusions. Etonogestrel - active substance in the composition of many last-generation oral contraceptives. The method developed by HPLC/MS is sensitive enough to determine the picogram of etonogestrel in human plasma.