Rapid and sensitive determination of selective progesterone modulator ulipristal acetate in human plasma

Abstract

Ulipristal acetate is a new synthetic selective progesterone receptor modulator developed mainly as emergency contraceptive (EC) and also used for the treatment of uterine fibroids. A cost effective, sensitive, simple and rapid high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of ulipristal acetate in human plasma. Following liquid-liquid extraction, the analyte (Ulipristal acetate) and internal standard (Levonorgestrel) were chromatographed using mobile phase in an isocratic elution mode on a reverse phase C18 column. The LC-MS/MS operated in multiple reaction monitoring mode for respective [M+H]⁺ ions, m/z 476.2/134.1 for analyte and 313.3/245.1 for internal standard. The assay exhibited linear dynamic range of 1-300 ng/mL. The lower limit of quantification was 1 ng/mL with relative standard deviation of 7.0%. The intra-batch and inter-batch results were precise with coefficient variation of 2.7 to 7.0 (%) and accuracy of 94.2-99.8 (%). The validated method was simple, fast and repeatable for bioequivalence, pharmacokinetic and therapeutic monitoring studies.