Detection And Metabolic Study Of SARMs For Doping Purpose

PURPOSE In this study, selective androgen receptor modulators(SARMs) and their metabolites were investigated by using liquid chromatography quadrupole mass spectrometry(LC-MS/MS) and liquid chromatography quadrupole time-of-flight mass spectrometry(LC-QTOFMS). This research provided a technical support for detection of SARMs in doping control.METHODS Liquid liquid extraction(LLE) method: One milliliter of urine was placed in a glass tube and buffered to pH 7.0 with 1 ml of a 0.8M phosphate buffer. Fifty microliters of ?-glucuronidase from E.coli and 100 ng of 17?-methyltestosterone,an internal standard were added, and the sample heated at 55oC for 1 h. After cooling to ambient temperature, 0.5ml of an aqueous solution containing potassium carbonate and potassium bicarbonate plus 4 ml of methyl tert-butyl ether were added, The organic layer was transferred to a fresh glass tube, flowed to dryness at 55 oC, and the dry residue dissolved in 100?l of mobile phase, injected for LC-MS-MS analysis. Solid phase extraction(SPE) method: Waters Sep-Pak C18 column were washed by 3mL water and 3mL methanol. One milliliter of rat urine were applied on the column. The methanol section was collected and evaporated to dryness at 55 oC after washing by 3mL water and methanol. The dry residue was dissolved in 150?l of mobile phase, injected for LC-QTOFMS analysis.RESULTS AND DISCUSSION The limits of detection(LODs) were all below 2 ?g/L. The recoveries were all higher than 60%. The intra-day and inter-day RSDs were all less than 20%. Three new andarine metabolites, eighteen new ostarine metabolites and eleven new LGD-4033 metabolites were found respectively in rat urine. CONCLUSIONS New method for simultaneous detection of 7 selective androgen receptor modulators(SARMs) was developed and validated. It was proved to be effective by testing 200 routine samples.