“…Fresh, pooled human blood plasma samples were from a local blood bank and stored at À80 C until use. Inactive hCES was prepared by denaturation using heat and organic solvent 4-fluoro-3a-tropacocaine and its 3b isomer were synthesized as described elsewhere (Kavanagh et al, 2012 (Darmstadt, Germany), ramipril from Hoechst (Frankfurt am Main, Germany), methylphenidate hydrochloride from Medice (Iserlohn, Germany), and thebacon and heroin hydrochloride were kindly provided by Prof. Robert Ammon (Homburg, Germany). Mitragynine was delivered from the Department of Forensic Medicine, Johannes Gutenberg University (Mainz, Germany), where it was isolated from kratom leaves obtained from Head & Nature (Regensburg, Germany) (Philipp et al, 2009).…”