Objective: The purpose of this study was to develop a low-cost, yet sensitive and precise UHPLC method for the quantitative determination of ostarine from dietary supplements (DS) for athletes. The analytical performance of the method was verified on a DS legally acquired from a specialized website for athletes. The uniformity of mass and content of the ostarine DS was also verified.
Methods: For the quantitative determination of ostarine a UHPLC method was developed and validated. The separation was performed using a reversed-phase C18 column, using a mixture of 75% methanol: 25% formic acid 0.1% in isocratic elution, at a flow rate of 0.5 ml/min. The uniformity of mass and content of DS was performed following the methodology described in the European Pharmacopoeia 7th Edition.
Results: The validated method was specific and linear on the concentration range of 1-25 µg/ml and was precise and accurate at all concentration levels, according to the official guidelines for validating analytical methods. An average mass of 510 mg content was obtained for the ostarine capsules, with an RSD of 2.41%. Regarding the uniformity of the content, an average of 4.65 mg ostarine/capsule was obtained with an RSD of 1.05%.
Conclusions: The developed UHPLC method was suitable, rapid, sensitive and allowed quantitative determination of active substance content in a DS with ostarine (92.91% ostarine/capsule from 5 mg ostarine/capsule declared by the manufacturer).
5. Hansson A Knych H Stanley S Thevis M Bondesson U Hedeland M. Investigation of the selective androgen receptor modulators S1 S4 and S22 and their metabolites in equine plasma using high-resolution mass spectrometry. Rapid Commun Mass Spectrom. 2016; 30(7):833-842.
6. Dobs AS Boccia RV Croot CC Gabrail NY Dalton JT Hancock ML Johnston MA Steiner MS. Efects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind randomised controlled phase 2 trial. Lancet Oncol. 2013; 14:335–345.
7. European Pharmacopoeia 7th Edition 2.9.5:265-266.
9. Cesbron N Sydor A Penot M Prevost S Le Bizec B Dervilly-Pinel G. Analytical strategies to detect enobosarm administration in bovines. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2017; 34(4):632-640.
11. Coss CC Jones A Dalton JT. Pharmacokinetic drug interactions of the selective androgen receptor modulator GTx-024(Enobosarm) with itraconazole rifampin probenecid celecoxib and rosuvastatin. Invest New Drugs. 2016; 34(4):458-67.
12. Thevis M Lagojda A Kuehne D Thomas A Dib J Hansson A Hedeland M Bondesson U Wigger T Karst U Schänzer W. Characterization of a non-approved selective androgen receptor modulator drug candidate sold via the Internet and identification of in vitro generated phase-I metabolites for human sports drug testing. Rapid Commun Mass Spectrom. 2015; 29(11):991-999.
13. Van Wagoner RM Eichner A Bhasin S Deuster PA Eichner D. Chemical Composition and Labeling of Substances Marketed as Selective Androgen Receptor Modulators and Sold via the Internet. JAMA. 2017; 318(20):2004-2010.