Recently abused β-keto derivatives of 3,4-methylenedioxyphenylalkylamines: a review of their metabolisms and toxicological analysis

beta-Keto derivatives of 3,4-methylenedioxyphenylalkylamines (bk-MDPAs), especially 2-methylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (methylone), 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB), and 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (bk-MDEA), are abused as substitutes for 3,4-methylenedioxyphenylalkylamines in some countries, causing increased social problems. With the widespread abuse of bk-MDPAs, the analysis of bk-MDPAs and their metabolites in human specimens is quite important in forensic and clinical toxicology. In this review, the metabolisms of bk-MDPAs and simultaneous analytical methods for bk-MDPAs and their metabolites by gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and liquid chromatography-tandem mass spectrometry are presented.