Urine-kinetics of Low Molecular Polyethylene Glycols Following an Oral Capsule Ingestion

Purpose: Urine marking is an alternative approach to supervise sample collection in order to prevent urine manipulation in the field of drug usage and the use of doping substances. Polyethylene glycols (PEG) with low molecular masses are already established as marker substances but their urine kinetics after oral capsule intake is not yet clearly described.

Methods: 26 subjects (both male and female) participated in the study. After determination of baseline urine they ingested a capsule containing 300 mg PEG (17 subjects PEG8 + PEG10, 9 subjects PEG8 + PEG 12; PEG8 = 370 g/mol, PEG10 = 458 g/mol, PEG12 = 546 g/mol) with 100 ml of fluid. Thereafter, subjects were instructed to completely drain the bladder every 15 minutes for the first hour and every 30 minutes for the following two hours after capsule intake. Thereafter, they were allowed to urinate spontaneously but had to notice the time on a protocol for a further 21 hours. From each sample, the PEG concentrations were determined by means of liquid chromatography mass spectrometry.

Results: PEG could be clearly detected in all subjects after 60 minutes, regardless of drinking volume, alcohol consumption, or urine flow. At the latest 22 hours following intake, the marker re-attained baseline values in all participants.

Discussion: PEG capsules can be used as safe means for urine marking in a time interval of at least 60 minutes between oral intake and urine sampling is respected. Furthermore, using different marker combinations, this method can be applied day by day in routine urine drug testing without interference with previously taken markers.