Liquid chromatography-tandem mass spectrometry for the determination of colchicine in postmortem body fluids. Case report of two fatalities and review of the literature.

Poisoning by colchicine may occur following ingestion of this alkaloid used for the treatment of acute gouty arthritis. The authors report two fatalities and describe a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) triple-quadrupole method for the determination of colchicine in autopsy samples. One milliliter of heart blood, femoral blood, urine, bile, gastric, and vitreous each were extracted with saturated NH4Cl at pH 9.6 and dichloromethane/5% isopropanol. Separation was achieved on a C18-Xterra column with a mobile phase consisting of 2 mM ammonium formate buffer (pH 3)/acetonitrile in a gradient mode. Four product ions of the protonated molecule were monitored. The method was fully validated in whole blood (1 mL) and was linear in the range of 0.5-50 ng/mL (r2>0.99). The limit of detection was 0.1 ng/mL (50 times S/N), and the limit of quantitation was 0.5 ng/mL with RSDs<11.8% intraday (n=6), <18.7% interday (n=18), and accuracy<3% (n=18). Case #1: a 33-year-old nurse committed suicide by the ingestion of 80 colchicine 1-mg tablets. She died 61 h later after resuscitation procedures. Colchicine was found in heart blood at 5.2 ng/mL, femoral blood at 17.4 ng/mL, urine at 19.4 ng/mL, bile at 42.8 ng/mL, gastric at 348 ng/mL, and vitreous at 3 ng/mL. Case #2: a 57-year-old man with gout was found dead at home. Colchicine was found in heart blood at 22.8 ng/mL, femoral blood at 21.9 ng/mL, lung blood at 45.2 ng/mL, urine at 148.5 ng/mL, bile at 1818.5 ng/mL, gastric at 219.8 ng/mL, and vitreous at 0.5 ng/mL. These results were consistent with death. Because of its good sensitivity, this LC-ESI-MS-MS triple-quadrupole method is suitable for the determination of colchicine not only in fatalities but also for pharmacokinetic studies.