| Reference | 1. Drug Test Anal. 2017 Feb;9(2):168-178. doi: 10.1002/dta.1930. Epub 2016 Jan 15.<br />
In vitro metabolism study of a black market product containing SARM LGD-4033.<br />
Geldof L(1), Pozo OJ(2), Lootens L(1), Morthier W(1), Van Eenoo P(1), Deventer K(1).<br />
Author information:<br />
(1)Doping Control Laboratory (DoCoLab), Ghent University (UGent), Department of Clinical Chemistry, Microbiology and Immunology, Technologiepark 30B, Zwijnaarde, B-9052, Belgium. (2)IMIM – Hospital del Mar Medical Research Institute, Bioanalysis Research Group, Doctor Aiguader 88, 08003, Barcelona, Spain.<br />
Anabolic agents are often used by athletes to enhance their performance. However, use of steroids leads to considerable side effects. Non-steroidal selective androgen receptor modulators (SARMs) are a novel class of substances that have not been approved so far but seem to have a more favourable anabolic/androgenic ratio than steroids and produce fewer side effects. Therefore the use of SARMs has been prohibited since 2008 by the World Anti-Doping Agency (WADA). Several of these SARMs have been detected on the black market. Metabolism studies are essential to identify the best urinary markers to ensure effective control of emerging substances by doping control laboratories. As black market products often contain non-pharmaceutical-grade substances, alternatives for human excretion studies are needed to elucidate the metabolism. A black market product labelled to contain the SARM LGD-4033 was purchased over the Internet. Purity verification of the black market product led to the detection of LGD-4033, without other contaminants. Human liver microsomes and S9 liver fractions were used to perform phase I and phase II (glucuronidation) metabolism studies. The samples of the in vitro metabolism studies were analyzed by gas chromatography-(tandem) mass spectrometry (GC-MS(/MS)), liquid chromatography-high resolution-tandem mass spectrometry (LC-(HR)MS/MS). LC-HRMS product ion scans allowed to identify typical fragment ions for the parent compound and to further determine metabolite structures. In total five metabolites were detected, all modified in the pyrrolidine ring of LGD-4033. The metabolic modifications ranged from hydroxylation combined with keto-formation (M1) or cleavage of the pyrrolidine ring (M2), hydroxylation and methylation (M3/M4) and dihydroxylation (M5). The parent compound and M2 were also detected as glucuronide-conjugates. Copyright © 2016 John Wiley & Sons, Ltd.<br />
2. J Gerontol A Biol Sci Med Sci. 2013 Jan;68(1):87-95. doi: 10.1093/gerona/gls078. Epub 2012 Mar 28.<br />
The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral, selective androgen receptor modulator, in healthy young men.<br />
Basaria S(1), Collins L, Dillon EL, Orwoll K, Storer TW, Miciek R, Ulloor J, Zhang A, Eder R, Zientek H, Gordon G, Kazmi S, Sheffield-Moore M, Bhasin S.<br />
Author information:<br />
(1)Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA 02118, USA.<br />
BACKGROUND: Concerns about potential adverse effects of testosterone on prostate have motivated the development of selective androgen receptor modulators that display tissue-selective activation of androgenic signaling. LGD-4033, a novel nonsteroidal, oral selective androgen receptor modulator, binds androgen receptor with high affinity and selectivity. Objectives. To evaluate the safety, tolerability, pharmacokinetics, and effects of ascending doses of LGD-4033 administered daily for 21 days on lean body mass, muscle strength, stair-climbing power, and sex hormones.<br />
METHODS: In this placebo-controlled study, 76 healthy men (21-50 years) were randomized to placebo or 0.1, 0.3, or 1.0 mg LGD-4033 daily for 21 days. Blood counts, chemistries, lipids, prostate-specific antigen, electrocardiogram, hormones, lean and fat mass, and muscle strength were measured during and for 5 weeks after intervention.<br />
RESULTS: LGD-4033 was well tolerated. There were no drug-related serious adverse events. Frequency of adverse events was similar between active and placebo groups. Hemoglobin, prostate-specific antigen, aspartate aminotransferase, alanine aminotransferase, or QT intervals did not change significantly at any dose. LGD-4033 had a long elimination half-life and dose-proportional accumulation upon multiple dosing. LGD-4033 administration was associated with dose-dependent suppression of total testosterone, sex hormone-binding globulin, high density lipoprotein cholesterol, and triglyceride levels. follicle-stimulating hormone and free testosterone showed significant suppression at 1.0-mg dose only. Lean body mass increased dose dependently, but fat mass did not change significantly. Hormone levels and lipids returned to baseline after treatment discontinuation.<br />
CONCLUSIONS: LGD-4033 was safe, had favorable pharmacokinetic profile, and increased lean body mass even during this short period without change in prostate-specific antigen. Longer randomized trials should evaluate its efficacy in improving physical function and health outcomes in select populations.<br />
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