Detection and quantification of methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in urine pain management compliance testing by high-pressure liquid chromatography with tandem mass spectrometry

摘要

Presently urine analysis for methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) is performed for emergency toxicology screening and pain management compliance testing (PMCT). Presented is the validation of a high-pressure liquid chromatography with tandem mass spectrometry method for methadone and EDDP in urine. Samples were simply diluted 1:1 (v:v) with 0.1 g/mL of methadone-d3 and EDDP-d 3 in methanol before analysis. The chromatographic separation was performed using a Pinnacle C18 100 × 3.2 mm, 3 m column with a mobile phase containing water/acetonitrile (20:80 v:v) with 1% formic acid delivered at a flow rate of 0.5 mL/min. Detection was accomplished by multiple-reaction monitoring via electrospray ionization source operating in the positive ionization mode. The calibration curve was linear over the investigated concentration range, 25 to 5000 ng/mL, for both methadone and EDDP. The lower limit of quantitation for each analyte was 25 ng/mL. The intra-and inter-day precisions had coefficient of variations less than 15% and the accuracy was within the range from 94% to 110%. The method proved adequate for methadone and EDDP analysis of urine for emergency clinical toxicology and PMCT.