Simultaneous determination of levonorgestrel and two endogenous sex hormones in human plasma based on LC–MS/MS

ABSTRACT Background: Levonorgestrel (LNG) is a commonly used emergency contraceptive which can effect sex hormone levels in female blood. The objective of this study was to develop and validate a specific and sensitive LC–MS/MS method for monitoring endogenous sex hormone levels (17β-estradiol and progesterone) in female plasma after administration of LNG. Results & methodology: The method was developed, optimized and validated according to the EMA guideline. Assay validation met all the criteria, including good linearity in the range of 0.1–20 ng/ml for 17β-estradiol, as well as 0.2–30 ng/ml for LNG and progesterone. Conclusion: The method has been preliminarily applied to...