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Doping is defined as the use of prohibited substances or methods by the World Anti-Doping Agency and the aim with doping control analysis is to detect the use of these illicit substances or methods. Substances that are prohibited in human or equine sports have either a positive or negative impact on the performance. Since administered drugs generally are metabolized to a varying degree and thereby not only excreted in their original form, their metabolite profiles are of high interest because drug metabolites may be present in the body for a longer time than the administered drug itself. Thereby detection of metabolites can improve the window of detection. Unfortunately, the metabolite profiles of non-approved drugs that are mainly available on the Internet, such as Selective Androgen Receptor Modulators (SARMs) are often unknown. This thesis consists of four papers that all encompass drug metabolite profiling either in vivo, in vitro or in a combination, utilizing separation with liquid chromatography and detection with high resolution mass spectrometry. In paper I and II, the equine in vivo metabolite profiles of the two SARMs ACP-105 and LGD-3303 were investigated and the results showed that using drug metabolites as analytical targets can prolong the detection time. For ACP-105, the in vivo metabolite profile was compared with different incubation models such as liver microsomes, S9 fractions and the fungus Cunninghamella elegans. The in vivo and in vitro metabolite profiles showed an interesting overlap for several metabolites, demonstrating the importance and usefulness for in vitro methods in doping control, especially since microsome incubates are allowed as reference material. An optimization of microsome incubation conditions utilizing experimental design was presented in paper III and IV, showing that the optimized conditions greatly impacted the yield of drug metabolites, but also that the optimal conditions are substance dependent. In paper III, a mult

Selective androgen receptor modulators (SARMs) such as ACP-105 are prohibited in sports due to their anabolic properties. ACP-105 has in previous equine studies shown to undergo extensive metabolism, which makes its metabolite profile important to investigate in humans, since the metabolism is unknown in this species. The aims of the study were to systematically optimize in vitro microsome incubations for improved metabolite yield and to utilize a multivariate data analysis (MVDA) approach to aid the metabolite discovery. Microsomes together with S9 fractions were used at optimal conditions, both with and without phase II additives. Furthermore, the relevance of the in vitro derived metabolites was evaluated as analytical targets in doping control by comparison with results from a human post-administration urine sample collected after a single dose of 100 µg ACP-105. All samples were analyzed with liquid chromatography - Orbitrap mass spectrometry. The use of the systematical optimization and MVDA greatly simplified the search and a total of 18 in vitro metabolites were tentatively identified. The yield of the two main monohydroxylated isomers increased by 24 and 10 times, respectively. In the human urine sample, a total of seven metabolites of ACP-105, formed by a combination of hydroxylations and glucuronic acid conjugations, were tentatively identified. The main metabolites were two monohydroxylated forms that are suggested as analytical targets for human doping control after hydrolysis. All the in vivo metabolites could be detected with the MVDA approach on the in vitro models, demonstrating its usefulness for prediction of the in vivo metabolite profile.

LGD-3303 is a Selective Androgen Receptor Modulator (SARM) that is prohibited in both equine and human sports due to its anabolic properties. The aim of this study was to investigate the equine in vivo metabolite profile of LGD-3303 and identify drug metabolites that can be suitable as new and improved analytical targets for equine doping control. This was performed by an oral administration of 0.05 mg.kg(-1) LGD-3303 to horses, where blood and urine samples were collected up to 96 h after administration. The in vivo samples consisting of plasma, urine and hydrolyzed urine were analyzed utilizing ultra-high performance liquid chromatography hyphenated to a Q Exactive (TM) Orbitrap (TM) high resolution mass spectrometer with a heated electrospray ionization source. A total of eight metabolites of LGD-3303 were tentatively identified, including one carboxylated and several hydroxylated metabolites in combination with glucuronic acid conjugates. A monohydroxylated metabolite is suggested as an analytical target for doping control analysis of plasma and urine after hydrolysis with beta-glucuronidase, due to the high intensity and prolonged detection time in comparison to parent LGD-3303.