Testing for clomiphene in keratinous matrices (hair and nail)

Clomiphene or clomifene is a selective estrogen receptor modulator used to treat female fertility in case of ovulatory dysfunction. In sport, clomiphene is prohibited at all times for use by athletes and is listed in the section S4.2 (hormone and metabolic modulators) by the World Anti-Doping Agency. Indeed, clomiphene can indirectly increase testosterone levels in the body and can mitigate some side effects of synthetic steroid abuse. Despite its prescription to millions of subjects, its detection in human hair or nail clippings has never been reported. The aim of this study was to develop a specific method to identify clomiphene in hair and nail clippings by liquid chromatography-quadrupole tandem mass spectrometry. The procedure was then applied in a case of challenged doping results. The method involves sonication/incubation for 1 h of 30 mg of pulverized material in 1 mL of methanol in the presence of 2 ng diazepam-d5 used as internal standard. The chromatographic separation was performed using a HSS C18 column with a 15 min gradient elution. After spiking blank hair and nail with the corresponding amounts of clomiphene, linearity was verified from 1 to 500 pg/mg (r2 = 0.9994 and 0.9995 for hair and nail, respectively). The limit of detection was estimated at 0.3 pg/mg for both matrices. No interference was noted from endogenous compounds, particularly steroids. Clomiphene was identified at 85 and 20 pg/mg in the pubic hair and the fingernail clippings, respectively, of a male athlete challenging an adverse analytical finding.