Comparison of Urinary Excretion Characteristics of Ethanol and Ethyl Glucuronide

Abstract

This study compared the urinary excretion characteristics of ethyl glucuronide (EtG) with that of ethanol, with focus on the effect of water-induced diuresis. Six healthy volunteers ingested an ethanol dose of 0.5 g/kg (range 25.0-41.5 g) as 5% (v/v) beer in 30 min and the same volume of water after 3 h. Urine collections were made before starting the experiment and at timed intervals over 31.5 h. The concentration of EtG was determined by an LC-MS method (LOQ = 0.1 mg/L). The urine samples collected immediately before starting drinking were all negative for ethanol and EtG, thus confirming that the participants had not recently ingested alcohol. Intake of beer resulted in a marked increase in excreted urine volume and a concomitant drop in creatinine concentration. The concentration of ethanol peaked at a mean value of 17 mmol/L in the 1.5-h urine collection. Except for one subject, EtG was first detectable (range 0.9-5.5 mg/L) at 1 h. Intake of water at 3 h produced another increase in urine volume and a drop in creatinine. The ethanol concentration curve was not influenced by the water diuresis, whereas this caused a distinct drop in the EtG concentration. When EtG was expressed relative to the creatinine value, this ratio was seemingly not affected by the intake of water. The ethanol concentration returned to zero at 6.5 h, whereas EtG was still detectable for up to 22.5-31.5 h, albeit at low levels in the end (< 1 mg/l). Only about 0.02% of the administered dose of ethanol (on a molar basis) was recovered in the urine as EtG. The results demonstrated that EtG remains detectable in the urine for many hours after the ethanol itself has been eliminated. Moreover, it was possible to lower the concentration of EtG by drinking large amounts of water prior to voiding, whereas this strategy did not influence the EtG/creatinine ratio or the concentration of ethanol.

Confirmatory analysis of ethylglucuronide in urine by liquid-chromatography/electrospray ionization/tandem mass spectrometry according to forensic guidelines

“…Figure 3 shows the typical ion chromatograms of the quantifier and two additional qualifiers for EtG in a urine sample (495 ng/mL EtG) obtained from a female volunteer 8 h after drinking 0.1 L of sparkling wine (9 g ethanol) in a controlled study. Figure 4 shows the time course of EtG elimination in this study; due to the correlation of EtG concentration and creatinine concentration [30], EtG100 was calculated by normalizing the measured EtG-and creatinine concentrations to a creatinine concentration of 100 mg/dL. In this study with nine volunteers, no EtG was detected in the baseline urine samples collected after one week of abstinence, and no interferences with other compounds were found in the retention time window of EtG (5.1 Ϯ 0.3 min) for the transitions of the quantifier and qualifiers.…”

“…Furthermore, these biomarkers can be influenced by age, gender, and a variety of substances and non-alcohol-associated diseases, and do not fully cover the time axis for alcohol intake. Conjugation of ethanol with activated glucuronic acid in the presence of membrane-bound mitochondrial UDP glucuronyl transferase represents a minor detoxification pathway for ethanol: About 0.02-0.06% (mean) of the dose of ethanol administered is recovered as ␤-D-ethylglucuronide (EtG) in urine in humans [1] and-dose dependent-0.5-1.5% in rabbits [2]. EtG is a non-volatile, water-soluble, stable, direct metabolite of ethanol that can be detected in various body fluids, tissues and hair.…”

Forensic confirmatory analysis of ethyl sulfate—A new marker for alcohol consumption—by liquid-chromatography/electrospray ionization/tandem mass spectrometry

“…The excretion profiles of the other volunteers showed similar characteristics, with longer excretion times after consumption of higher amounts of ethanol (up to 36 h after 49 g ethanol uptake). Due to the correlation of EtG concentration and creatinine concentration [15], EtS-100 and EtG-100 were calculated by normalizing to a creatinine concentration of 100 mg dL Ϫ1 .…”

Mass Spectrometric Identification of Ethyl Sulfate as an Ethanol Metabolite in Humans

“…According to the self-report, he had abstained from alcohol for at least 48 h before starting the experiment. EtS and EtG are expressed in relation to creatinine to compensate for variations in urine dilution (1 ). The ethanol concentration peaked at 2 h and had returned to below the detection limit at 8 h. EtS was not detected in the first urine sample (0 h) but was detected in the second sample, collected at 1 h after intake.…”