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Anal Bioanal Chem (2014) 406:18451854 DOI 10.1007/s00216-013-7539-0
PAPER IN FOREFRONT
Dimethocaine, a synthetic cocaine analogue: studieson its in-vivo metabolism and its detectability in urineby means of a rat model and liquid chromatographylinear ion-trap (high-resolution) mass spectrometry
Markus R. Meyer & Carina Lindauer & Jessica Welter &
Hans H. Maurer
Received: 23 October 2013 /Revised: 19 November 2013 /Accepted: 26 November 2013 /Published online: 22 January 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Dimethocaine (DMC, larocaine), a synthetic derivative of cocaine, is a widely distributed legal high consumed as a new psychoactive substance (NPS) without any safety testing, for example studies of metabolism. Therefore, the purpose of this work was to study its in-vivo and in-vitro metabolism by use of liquid chromatography(high resolution) mass spectrometry (LCHRMSn). DMC was administered to male Wistar rats (20 mg kg1) and their urine was extracted either by solid-phase extraction after enzymatic cleavage of conjugates or by use of protein precipitation (PP). The metabolites were separated and identified by LC HRMSn. The main phase I reactions were ester hydrolysis, deethylation, hydroxylation of the aromatic system, and a combination of these. The main phase II reaction was N-acetylation of the p-aminobenzoic acid part of the unchanged parent compound and of several phase I metabolites. The metabolites identified were then used for identification of DMC in rat urine after application of a common users dose. By use of GCMS and LCMSn standard urine-screening approaches (SUSAs), DMC and its metabolites could be detected in the urine samples.
Keywords Designer drug . DMC . Cocaine . Metabolism .
Urine screening . GCMS . LCMSn . LCHRMSn
Introduction
Dimethocaine (DMC, larocaine, 3-diethylamino-2,2-dimethylpropyl)-4-aminobenzoate) was used in the 1930s as a local anesthetic in dentistry and ophthalmology [1]. It also acts as dopamine-reuptake inhibitor with stimulating effects similar to those of cocaine [2-5] and was, therefore, removed from the market because of these psychoactive effects. In the meantime DMC attracted the attention of the worldwide drugs scene and it is distributed as a legal cocaine replacement, as so-called new psychoactive substance (NPS). It is even listed by the European Monitoring Centre for Drugs and Drug Addiction under the category synthetic cocaine derivatives and offered in numerous online shops [6]. After consumption of DMC, consumers describe feelings of euphoria...