SOSVOROVA, L.K., SAREK, J., VITKU, J., KVASNICA, Miroslav. Synthesis of 3 alpha-deuterated 7 alpha-hydroxy-DHEA and 7-oxo-DHEA and application in LC-MS/MS plasma analysis. Steroids. 2016, 112(AUG), 88-94. ISSN 0039-128X. E-ISSN 1878-5867

7-Oxygenated metabolites of dehydroepiandrosterone (DHEA) are known for their neuroprotective and immunomodulatory properties. These neuroactive steroids are currently predominately analysed by mass spectrometry, for which the use of internal deuterated standards is necessary. The aim of this study was to synthesize the deuterated derivatives of 7 alpha-hydroxy-DHEA and 7-oxo-DHEA and test them in liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to enhance the performance characteristics of this method. Here we report the synthesis of 3 alpha deuterium-labelled 7 alpha-hydroxy-DHEA and 7-oxo-DHEA. Deuterium was introduced into the 3 alpha position by reduction of the corresponding 3-ketone with a protected 17-carbonyl group using NaBD4. Our new procedure allows the easier synthesis of deuterated steroid labelled compounds. The use of these deuterated steroids enabled us to improve the human plasma LC-MS/MS analysis of 7 alpha-hydroxy-DHEA and 7-oxo-DHEA in terms of sensitivity, precision and recovery.