Monitoring alcohol-use-disorder medication compliance by LC-MS/MS determination of urinary ethyl glucuronide, acamprosate, naltrexone, and 6β-naltrexol using zirconia-based hybrid solid-phase extraction

Abstract

Alcohol use disorder (AUD) is a major risk factor for numerous social concerns worldwide. In the Republic of Korea, the court imposes compulsory medication treatment on criminals diagnosed with AUD who are on probation. The purpose of the treatment is to reduce the number of repeat offenses committed by AUD-afflicted criminals. In this study, a method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine ethyl glucuronide (EtG), acamprosate (ACAM), naltrexone (NTX), and 6β-naltrexol (6BNT) in urine was developed and validated to monitor the medication compliance and alcohol use of probationers diagnosed with AUD. A zirconia-based hybrid solid-phase extraction technique was introduced to increase the sensitivity toward target analytes having significantly differing pKa values while minimizing the matrix effect of the urine sample. The pretreated urine samples were analyzed by LC-MS/MS performed in a polarity-switching electrospray ionization mode via a three-period multiple-reaction monitoring method. All the target analytes were separated and detected within 6.5 min with an Xselect HSS T3 column and gradient elution using water containing 0.02% formic acid and methanol as the mobile phase. The lower limits of quantification of EtG, ACAM, NTX, and 6BNT were 10.0, 4.0, 0.4, and 0.2 ng mL^-1, respectively. The determination coefficients of each calibration curve were greater than 0.9989. The intra-day accuracy ranged from -5.5-5.3% and the precision was ≤ 5.7%, whereas the inter-day accuracy ranged from -5.3-4.6% and the precision was ≤ 4.7%. The recovery, matrix effect, and process efficiency were 99.7-107.9%, 80.7-101.8%, and 80.5-108.1%, respectively. The developed method was successfully applied to analyze 107 urine samples obtained from probationers undergoing medication treatment for AUD and to monitor the probationers' medication compliance and alcohol use. This study also determined the urinary concentrations of EtG, ACAM, NTX, and 6BNT as well as the metabolic ratio of NTX following repeated oral administration of AUD medications.

Keywords: Acamprosate; Alcohol use disorder; Ethyl glucuronide; Naltrexone; Urinalysis; Zirconia-based hybrid solid–phase extraction.