Simultaneous determination of mifepristone and monodemethyl‐mifepristone in human plasma by liquid chromatography–tandem mass spectrometry method using levonorgestrel as an internal standard: application to a pharmacokinetic study

Abstract

A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine mifepristone and monodemethyl-mifepristone in human plasma using levonorgestrel as the internal standard (IS). After solid-phase extraction of the plasma samples, mifepristone, monodemethyl-mifepristone and the IS were subjected to LC-MS/MS analysis using electro-spray ionization (ESI) in the multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an XTERRA MS C(18) column (150 x 2.1 mm i.d., 5 microm). The method had a chromatographic run time of 4.5 min and linear calibration curves over the concentration ranges of 5-2000 ng/mL for mifepristone and monodemethyl-mifepristone. The recoveries of the method were found to be 94.5-103.7% for mifepristone and 70.7-77.3% for monodemethyl-mifepristone. The method had a lower limit of quantification (LLOQ) of 5.0 ng/mL and a lower limit of detection (LOD) of 1.0 ng/mL for both mifepristone and monodemethyl-mifepristone. The intra- and inter-batch precision was less than 15% for all quality control samples at concentrations of 10, 100 and 1000 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity. The validated LC-MS/MS method was successfully used in a pharmacokinetic study in healthy female volunteers after oral administration of 25 mg mifepristone tablet.

The Unique Pharmacological Characteristics of Mifepristone (RU486): From Terminating Pregnancy to Preventing Cancer Metastasis

“…Metapristone is the most predominant metabolite in human body that can be easily and reliably detected. Blood concentrations of metapristone are higher than or equal to those of the parent drug mifepristone . On the other hand, plasma concentrations of metapristone are usually higher than those of RU42848 and RU42698 .…”

“…After a single oral administration of mifepristone at different doses (25, 50, 100, 200, 400, or 600 mg per person), mifepristone could be detected for at least 4 days, or even 10 days later in some subjects . Plasma concentrations of mifepristone increased following single oral administration escalation from 25 up to 100 mg, and no further increase in mifepristone was detected as doses were increased from 100 to 800 mg per person.…”

“…) . Many human pharmacokinetic studies have shown that after 0.5–1 hr of oral administration of mifepristone, its metabolites, namely, the N ‐monodemethyl mifepristone (RU42633, metapristone), N ‐didemethyl mifepristone (RU42848), and hydroxylated mifepristone (RU42698) formed immediately . Metapristone is the most predominant metabolite in human body that can be easily and reliably detected.…”

Determination of cymipristone in human plasma by liquid chromatography–electrospray ionization-tandem mass spectrometry

“…However, methods of determination of cymipristone in biological fluids have never been reported. Earlier publications have described methods for the analysis of mifepristone by LC-MS/MS [6,7]. In this paper, a new liquid chromatography-electrospray ionization-tandem mass spectrometry method using mifepristone as the internal standard (IS) was established and validated, and it was successfully applied to a pharmacokinetic study of cymipristone in healthy Chinese female subjects.…”

Influence of number of calibration standards within a defined range on pharmacokinetic disposition—case studies with omeprazole and clopidogrel carboxylic acid

“…While the lower bound is greatly infl uenced by factors such as method of sample extraction (protein precipitation, solid-phase extraction or liquid-liquid extraction), detection platform and inherent attributes of the analyte etc., the upper bound is generally dictated by the saturation of the instrument's dynamic response. It is not uncommon to construct calibration curves that cover a more than 100-fold range in order to characterize the pharmacokinetics from starting low human doses to the anticipated maximum tolerated dose (MTD) in fi rst-in-man clinical protocols and also for application in bioequivalence/pharmacokinetic studies (Vijaya Bharathi et al, 2009;Zhang and Chen, 2009;Tang et al, 2009;Zeng et al, 2009;Jiang et al, 2009;Arnold et al, 2008;Handy et al, 2008;Minkin et al, 2008;Jain et al, 2008;Xue et al, 2007;Zeng et al, 2007;Xu et al, 2007;Shen et al, 2004;Upreti et al, 2003). Additionally, the existence of a 100-fold range may be useful when dealing with NCEs that are substrates for polymorphic cytochrome P450 (CYP) isozymes wherein logorders of diff erences in the plasma concentrations of the parent and/or metabolite are expected to occur between the extensive metabolizer and poor metabolizer phenotypes (Preskorn et al, 2009;Shao et al, 2009;Davies et al, 2008;Stamer et al, 2007;Shilbayeh and Tutunji, 2006;Inomata et al, 2005).…”