title: Measurement of ethyl glucuronide, ethyl sulphate and their ratio in the urine and serum of healthy volunteers after two doses of alcohol.
abstract: OBJECTIVE
  Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are minor metabolites of ethanol, and their presence in urine provides a strong indication of recent alcohol administration. In this study, we performed a drinking experiment to investigate the kinetics of EtG and EtS formation and elimination after the administration of two doses of alcohol.
  
  
  METHODS
  Nineteen volunteers provided urine and serum (only 18) after administration of 4 and 8 units of alcohol (1 unit corresponds to 10 ml or ∼8 g of pure ethanol). The analysis was performed using a validated ultra-performance liquid chromatography-mass spectrometry (UPLC(®)-MS/MS) method.
  
  
  RESULTS
  After 4 units, the median EtG maximum concentration (C(max)) was 0.4 µg/ml and the interquartile range (0.3 µg/ml) in serum and 3.5 mg/h (1.2 mg/h) in urine and were reached (T(max)) after 2.0 h (0.8 h) and 3.0 h (1.0 h), respectively. EtS C(max) was 0.2 µg/ml (0.1 µg/ml) in serum and 1.3 mg/h (0.6 mg/h) in urine, and the corresponding T(max) were 1.0 h (1.0 h) and 2.0 h (0.5 h). After 8 units, EtG C(max) was 1.3 µg/ml (0.4 µg/ml) in serum and 10 mg/h (3.4 mg/h) in urine and was reached after 4.0 h (1.8 h) and 4.0 h (2.0 h), respectively. EtS C(max) was 0.6 µg/ml (0.1 µg/ml) in serum and 3.5 mg/h (1.1 mg/h) in urine, the corresponding T(max) were 3.0 h (1.0 h) and 3.0 h (1.0 h). The EtG/EtS ratio increased as a function of the time after alcohol administration in both serum and urine samples but to a lesser extent after 8 units than 4.
  
  
  CONCLUSIONS
  These results correlate with values obtained in previous studies. T(max) of EtG and EtS increased between 4 and 8 units. The EtG:EtS ratio increased in the serum and urine samples of all volunteers as a function of time at least up to 4 h after alcohol administration.
authors.affiliation: Drug Control Centre, Department of Forensic Science and Drug Monitoring, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London, UK.
authors.forename: Alfonso Maria
authors.initials: AM
authors.lastname: Lostia
authors.forename: Joana Lobo
authors.initials: JL
authors.lastname: Vicente
authors.forename: David A
authors.initials: DA
authors.lastname: Cowan
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000097:blood* / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D000431:Ethanol / Q000008:administration & dosage / Q000097:blood / Q000652:urine; D005260:Female; D005965:Glucuronates / Q000097:blood* / Q000652:urine*; D006801:Humans; D008297:Male; D013463:Sulfuric Acid Esters / Q000097:blood* / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005965:Glucuronates; D013463:Sulfuric Acid Esters; C093924:ethyl glucuronide; D000431:Ethanol; C011612:diethyl sulfate