Determination of the concentration of selective progesterone receptor modulators in blood plasma BY LC–MS/MS

Abstract

High-performance liquid chromatography mass spectrometry is a hybrid method and combines independent processes of liquid chromatographic separation and mass spectrometric analysis, which makes it possible to effectively determine the concentration of various substances in complex substances. The optimal parameters for the determination of progesterone, 17-hydroxyprogesterone capronate (17-OHPC) and aglepriston in the blood plasma of cattle by this method have been established in the work. The quantitative determination of the components was carried out by the method of an external standard using reference substances and preliminary construction of calibration dependencies (absolute calibration). To account for the effect on the result of the analysis of various components of blood plasma, the matrix calibration method was used using "pure" plasma, i.e., it did not contain detectable compounds. It was experimentally determined that the time of progesterone peak release is within 2.72 minutes, and the optimal precursor ion is m/z =315.3. In the course of the work carried out, it was found that in the blood plasma of animals, endogenous progesterone is well detected by the developed method according to the parameters set for the synthetic analogue. The peak time of 17-OHPC occurred after 4.20 minutes, and the optimal precursor ion had a mass of 429.2 au. The first stage of studying the kinetics of 17-HPC in cattle showed that the steroid is well visualized on the chromatogram even in low concentrations. The outputs of the peaks of aglepriston were observed at 2.25 minutes, and the optimal precursor ion was equal to 432.2 au.m. The chromatogram even at low concentrations of the steroid had a low noise level, and the concentration of the steroid in the blood plasma a day after injection of 20 ml of 3% aglepriston solution to a lactating cow was 7.2 ng/ml. Thus, optimal parameters were selected for determining the concentration of selective progesterone receptor modulators in the blood plasma of cattle, which allows for further evaluation of the pharmacokinetic properties of these steroids after their use.