Methadone disposition in oral fluid during pharmacotherapy for opioid-dependence

Dental Plaque Concentrations of Methadone, Morphine and Their Metabolites in Opioid Replacement Therapy and in Post-Mortem Cases

Non-mineralized dental biofilm (plaque) has potential as novel alternative matrix in forensic toxicology to prove drug use. The incorporation of illicit and medicinal drugs in dental plaque could take place through direct contact after oral or nasal intake, which can lead to high drug levels in the oral cavity, or indirectly via the secretion of drug-containing saliva, e.g. after intravenous application. Therefore, plaque samples from patients in opioid replacement therapy (ORT) and post-mortem plaque samples were analyzed and the drug concentrations were compared. The study comprised 26 plaque samples from ORT patients with different daily doses which were analyzed for methadone, morphine and their respective metabolites. Plaque samples were taken directly before the oral administration of the regular daily dose. Seventeen post-mortem plaque samples were analyzed, either from cases of lethal drug intoxications or after pain therapy with morphine. Plaque analysis was performed using LC-MS/MS after liquid extraction with acetonitrile. Plaque concentrations in ORT for methadone and its metabolite EDDP ranged from 42 to approx. 49,000 pg/mg (median 1,300 pg/mg) and from below 10 to 610 pg/mg (median 31 pg/mg), respectively. Morphine plaque concentrations in ORT ranged from 120 to 480 pg/mg (median 400 pg/mg). In lethal intoxication cases plaque concentrations were generally at least one order of magnitude higher than in the study groups with therapeutic substance use. This data will help to interpret drug findings in plaque. Additionally, the EDDP/methadone concentration ratio in plaque was lower after oral intake with contamination of the oral cavity (e.g. syrup) compared to cases with suspected intravenous application of methadone and could therefore indicate the drug administration route.

Oral Fluid Drug Testing: Analytical Approaches, Issues and Interpretation of Results

With advances in analytical technology and new research informing result interpretation, oral fluid (OF) testing has gained acceptance over the past decades as an alternative biological matrix for detecting drugs in forensic and clinical settings. OF testing offers simple, rapid, non-invasive, observed specimen collection. This article offers a review of the scientific literature covering analytical methods and interpretation published over the past two decades for amphetamines, cannabis, cocaine, opioids, and benzodiazepines. Several analytical methods have been published for individual drug classes and, increasingly, for multiple drug classes. The method of OF collection can have a significant impact on the resultant drug concentration. Drug concentrations for amphetamines, cannabis, cocaine, opioids, and benzodiazepines are reviewed in the context of the dosing condition and the collection method. Time of last detection is evaluated against several agencies' cutoffs, including the proposed Substance Abuse and Mental Health Services Administration, European Workplace Drug Testing Society and Driving Under the Influence of Drugs, Alcohol and Medicines cutoffs. A significant correlation was frequently observed between matrices (i.e., between OF and plasma or blood concentrations); however, high intra-subject and inter-subject variability precludes prediction of blood concentrations from OF concentrations. This article will assist individuals in understanding the relative merits and limitations of various methods of OF collection, analysis and interpretation.

Oral fluid for the detection of drugs of abuse using immunoassay and LC–MS/MS

The utility of oral fluid as a sample matrix for the analysis of drugs has been increasing in popularity over the last few years. This is largely because of collection advantages over other matrices, but also due to the rapid improvements in analytical assays including highly sensitive liquid reagent format enzyme immunoassays and LC–MS/MS. This review will highlight improvements in assay formats, sensitivity, laboratory equipment and sample processing using low sample volumes to expand drug test profiles.