Metabolism and toxicological detection of the new designer drug 3',4'-methylenedioxy-alpha-pyrrolidinopropiophenone studied in urine using gas chromatography-mass spectrometry.

R,S-3',4'-Methylenedioxy-alpha-pyrrolidinopropiophenone (MDPPP) is a new designer drug with assumed amphetamine-like effects, which has appeared on the illicit drug market. The aim of this study was to identify the MDPPP metabolites using solid-phase extraction, ethylation or acetylation as well as to develop a toxicological detection procedure in urine using solid-phase extraction, trimethylsilylation and GC-MS. Analysis of urine samples of rats treated with MDPPP revealed that MDPPP was completely metabolized by demethylenation of the methylenedioxy group followed by partial 3'-methylation of the resulting catechol, oxidative desamination to the corresponding diketo compounds and/or hydroxylation of the pyrrolidine ring with subsequent dehydrogenation to the corresponding lactam. The hydroxy groups were found to be partly conjugated. Based on these data, MDPPP could be detected in urine via its metabolites by full-scan GC-MS using mass chromatography for screening and library search for identification by comparison of the spectra with reference spectra.