Successful Resuscitation of a Patient with Life-Threatening Metabolic Acidosis by Hemodialysis: A Case of Ethylene Glycol Intoxication

Novel Technique for Simultaneous Ethylene Glycol and Its Metabolites Determination in Human Whole Blood and Urine Samples Using GC-QqQ-MS/MS

Toxicological analyses often necessitate the identification of compounds belonging to diverse functional groups. For GC-MS analyses, derivatization of compounds belonging to different functional groups can pose a challenge and requires the development of comprehensive methods of analysis. One example could be ethylene glycol, whose widespread use is related to possible unintentional or suicidal intoxications. This fact clearly indicates the need to develop sensitive methods for the determination of ethylene glycol and its metabolites in biological material, as only such complex analysis allows for proper toxicological expertise. A simultaneous GC-QqQ-MS/MS method for the determination of ethylene glycol together with its metabolites, glyoxal and glycolic acid, as well as the detection of glyoxylic acid and oxalic acid, was developed and fully validated. A novel approach for simultaneous derivatization of substances from different groups (alcohols, aldehydes, and carboxylic acids) was established. Sample preparation included the addition of three internal standards (BHB-d4, ethylene glycol-d4 and methylglyoxal), precipitation with acetonitrile and subsequent derivatization with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA), as well as pentafluorophenylhydrazine (PFPH). Detection was carried out with the use of triple quadrupole mass spectrometer. The ionization method was electron impact, and quantitative analysis was carried out in multiple reaction monitoring mode. The lower limit of quantification was 1 μg/mL, 0.1 μg/mL, and 500 μg/mL for ethylene glycol, glyoxal, and glycolic acid, respectively. The presented method was applied in three authentic postmortem cases of ethylene glycol intoxication.

Prediction of Human Pharmacokinetics of Fomepizole from Preclinical Species Pharmacokinetics Based on Normalizing Time Course Profiles

Fomepizole is used as an antidote to treat methanol poisoning due to its selectivity towards alcohol dehydrogenase. In the present study, the goal is to develop a method to predict the fomepizole human plasma concentration versus time profile based on the preclinical pharmacokinetics using the assumption of superimposability on simulated time course profiles of animals and humans. Standard allometric equations with/without correction factors were also assimilated in the prediction. The volume of distribution at steady state (Vss) predicted by simple allometry (57.55 L) was very close to the reported value (42.17 L). However, clearance (CL) prediction by simple allometry was at least 3-fold higher to the reported value (33.86 mL/min); hence, multiple correction factors were used to predict the clearance. Both brain weight and maximum life span potential could predict the CL with 1.22- and 1.01-fold difference. Specifically, the predicted Vss and CL values via interspecies scaling were used in the prediction of series of human intravenous pharmacokinetic parameters, while the simulation of human oral profile was done by the use of absorption rate constant (Ka) from dog following the applicability of human bioavailability value scaled from dog data. In summary, the findings indicate that the utility of diverse allometry approaches to derive the human pharmacokinetics of fomepizole after intravenous/oral dosing.