This study assessed the stability of synthetic cathinone's in urine and blood over a period of 6 months, using liquid-chromatography/quadrupole-time of flight-mass spectrometry (LC-Q/TOF-MS), so as to understand drug stability in biological evidence examined in criminal and death investigations.
The study determined that cathinone stability is highly dependent on temperature, pH, and analyte. No concentration dependence was observed. Cathinones were most stable when frozen in acidic urine, and they were least stable under alkaline conditions at elevated temperatures. The chemical structure of these polyfunctional aminoketones had a significant influence on stability. Under some conditions, drugs were undetectable within 24 hours of storage. Under all conditions tested, the pyrrolidone-type cathinones were the most stable, followed by the methylenedioxy-type, ring-substituted, and unsubstantiated cathinones. Both the methylenedioxy and pyrrolidinyl substituents exerted a significant stabilizing effect. Twenty-two cathinones were selected for the study based on their structural features and functional substituents. Cathinones bearing secondary and tertiary (pyrrolidinyl) amines, ring substituents, and methylenedioxy substituents were included in the study. Cathinone stability was assessed in urine at pH 4 and 8 and at physiological pH in blood to determine analyte, pH, concentration, and temperature (-20 degrees centigrade, 20 degrees centigrade, and 32 degrees centigrade). These findings highlight the need for quantitative drug findings in toxicological investigations to be interpreted cautiously, with attention to the context of specimen storage and integrity. 25 tables, 23 figures, and 57 references