Excretion study of clomiphene in human urine: evaluation of endogenous steroids profile after multiple oral doses

Selective estrogen receptor modulators are classified as prohibited substances according to the list of forbidden substances in sports by the International Olympic Committee and the World Anti-doping Agency. Clomiphene (2-(4-(2-chloro-1,2-diphenylethenyl)phenoxy)-N,N-diethyl-ethanamine) is mainly used for the treatment of infertility because it acts inducing the ovulation by direct stimulations of gonadotropic activity. Clomiphene citrate (50 mg per day for 5 days) was orally administered to one healthy female with infertility treatment. Urine samples were collected up to 1 week post-dose. A new metabolite using gas chromatography-mass spectrometry has been identified in addition to the hydroxyclomiphene previously reported. It has been proposed as hydroxymethoxyclomiphene. Monitorization of this metabolite have been proposed for doping control keeping in mind that the main metabolite hydroxyclomiphene is excreted relatively faster than hydroxymethoxyclomiphene from urine. On the other hand, significant changes on steroids profile after multiple doses were observed. The main variation was observed on absolute concentration of oestrogens and their ratios.