Towards adherence monitoring using breath or oral fluid as a matrix in a methadone maintenance treatment program for patients with a chronic heroin use disorder: Issues and interpretation of the results

Urine has been the preferred matrix for monitoring heroin and methadone adherence due to its large detection window. Drawbacks such as privacy concerns and adulteration however require other matrices. The study aims to determine if oral fluid and exhaled breath are suitable alternatives for heroin and methadone monitoring and to assess the detection time in exhaled breath. Forty-three participants, all on methadone and heroin-assisted treatment, were studied. Participants were monitored after the first and right before the second dosage of heroin. At both time points, oral fluid and exhaled breath samples were collected with urine at the second time point. All samples were screened for opiates, methadone and other drugs using immunoassay and LC-MS-MS. At the second time point, 98% of oral fluid samples and all exhaled breath samples tested positive for 6-monoacetylmorphine (6-MAM). Regarding morphine detection, the findings were reversed (100% in oral fluid, 98% in exhaled breath). Methadone-related results were 100% positive across all matrices, as expected. Notable is the detection of the heroin marker acetylcodeine in oral fluid and exhaled breath samples, which resulted in relatively low negative predictive value (average 54.6%). Oral fluid and exhaled breath are suitable alternatives for heroin and methadone maintenance monitoring. Clinicians should consider ease of collection, adulteration risk, costs, turn-around time and the substance of interest while choosing a matrix. In addition, even in cases when medicinal heroin is used, medical professionals should be aware of the presence of acetylcodeine in these alternate matrices.

Recent advances of drugs monitoring in oral fluid and comparison with blood

The use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Oral fluid (OF), as non-invasive fluid, has attracted attention in the field of drug screening, both for therapeutic and forensic purposes, as well as for medical diagnosis, clinical management, on-site (real time) doping and for monitoring environmental exposure to toxic substances. A good correlation between OF and blood is now established for drug concentrations. Therefore, OF might be a potential substitute of blood, especially for long-term surveillance (e.g., therapeutic drugs) or to screen a large number of patients, as well as for the development of salivary point-of-care technologies. In this review, we aimed to summarize and critically evaluate the current literature that focused on the comparison of drugs detection in OF and blood specimens.

Hydromorphone and codeine concentrations in oral fluid specimens from patients receiving substitution therapy with Substitol™ (morphine sulfate)

This study aimed to determine whether hydromorphone and codeine can be detected in oral fluid specimens following administration of Substitol™, a slow-release formulation of morphine. This is of interest for those monitoring treatment compliance using drug testing. Oral fluid specimens collected for compliance assessment in routine clinical practice or as part of a clinical trial were subjected to quantitative analysis of hydromorphone, morphine, codeine, and 6-acetylmorphine using highly sensitive mass spectrometric methods. Oral fluid was collected using a Greiner Bio-One saliva collection system. Patients undergoing substitution treatment with Substitol™, methadone, or buprenorphine were included, together with patients undergoing pain treatment with hydromorphone. Hydromorphone was detected in 642 of the 663 (97%) samples from substitol-treated patients. Concentrations were not higher in methadone- and buprenorphine-treated patients who relapsed into heroin use, or in patients on hydromorphone therapy. Codeine was detected in 29% of the samples. These concentrations were lower than those in patients who had relapsed to heroin use. Clinical administration of morphine can lead to detectable concentrations of both hydromorphone and codeine in oral fluids. This should be taken into consideration when using drug testing in oral fluid samples for compliance assessment in this patient group.

Detection of codeine and fentanyl in saliva, blood plasma and whole blood in 5-minutes using a SERS flow-separation strip

A simple-to-use device to measure drugs in saliva, blood plasma, and whole blood for point-of-care analysis and treatment of overdose patients has been investigated. A rudimentary flow strip has been developed to separate opioids from these biofluids for analysis by surface-enhanced Raman spectroscopy (SERS). The strips are based on lateral flow assays, in which the antibodies have been substituted by SERS-active pads for detection. Samples of codeine and fentanyl, artificially added to these biofluids, were measured using the strips by a field-usable Raman spectrometer. We report measurement of these drugs in these biofluids from 0.5 to 5 μg mL-1 in 5 minutes. Calculated limits of detection for the spectra suggest that these drugs could be measured at 5 to 20 ng mL-1 with improvements in the strips' separation capability.

Development of a Quantitative LC-MS-MS Assay for Codeine, Morphine, 6-Acetylmorphine, Hydrocodone, Hydromorphone, Oxycodone and Oxymorphone in Neat Oral Fluid

Recent advances in analytical capabilities allowing for the identification and quantification of drugs and metabolites in small volumes at low concentrations have made oral fluid a viable matrix for drug testing. Oral fluid is an attractive matrix option due to its relative ease of collection, reduced privacy concerns for observed collections and difficulty to adulterate. The work presented here details the development and validation of a liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the quantification of codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone and oxymorphone in neat oral fluid. The calibration range is 0.4-150 ng/mL for 6-acetylmorphine and 1.5-350 ng/mL for all other analytes. Within-run and between-run precision were <5% for all analytes except for hydrocodone, which had 6.2 %CV between runs. Matrix effects, while evident, could be controlled using matrix-matched controls and calibrators with deuterated internal standards. The assay was developed in accordance with the proposed mandatory guidelines for opioid confirmation in federally regulated workplace drug testing. The use of neat oral fluid, as opposed to a collection device, enables collection of a single sample that can be split into separate specimens.

Analysis of Drugs in Oral Fluid Using LC-MS/MS

Oral fluid analysis for drugs is increasingly used in a variety of testing areas: pain management and medication monitoring, parole and probation situations, driving under the influence of drugs (DUID), therapeutic drug monitoring, and testing for drugs in the workplace. The sample collection itself is straightforward, rapid, observable, and noninvasive, requiring no special facilities (compared to urine) or medical personnel (compared to blood). The pH of saliva is slightly acidic relative to blood; therefore, drugs which are more basic tend to be present in higher concentration in oral fluid than in blood: cocaine, amphetamines, oxycodone, tramadol, buprenorphine, methadone, and fentanyl. Conversely, acidic drugs and drugs which are strongly protein bound have lower concentrations in oral fluid than in blood: examples include benzodiazepines, barbiturates, and carisoprodol. Because of the low volume of specimen available for analysis and the drug concentrations present (generally much lower than those in urine), efficient extraction methods and sensitive confirmation procedures are necessary for routine analysis of drugs in oral fluid. In this chapter, solid-phase extraction methods are described for a variety of drugs with liquid chromatography-tandem mass spectrometry detection.

Potential of Oral Fluid as a Clinical Specimen for Compliance Monitoring of Psychopharmacotherapy

BACKGROUND

Oral fluid (OF) is being developed as a specimen for the determination of drug intake as an alternative to serum and plasma. It is generally considered as an attractive specimen due to the noninvasive nature of the sampling procedure and the relation to the free fraction of drug in the blood. These features are of particular value in drug treatment of psychiatric disorders. To establish OF for the purpose of monitoring drug therapy, the relationship between concentrations in OF and serum/plasma must be documented. This study explored one promising sampling device and comprised the following 10 drugs: aripiprazole, citalopram, duloxetine, escitalopram, mirtazapine, pipamperone, pregabalin, promethazine, quetiapine, and venlafaxine.

METHODS

For this purpose, 100 paired serum and OF samples were collected from patients undergoing pharmacotherapy and analyzed using a liquid chromatography-tandem mass spectrometry method. A commercial method from Chromsystems for the determination of these drugs in plasma was used and was adapted for OF and ultrafiltrated (Centrifree device) serum.

RESULTS

The ratio of each individual pair of samples was used to calculate a mean and SD value between OF and serum free and total concentrations. The OF concentration ratios to serum total fraction differed markedly between substances and differed from 10-fold lower to 8-fold higher. The ratios to serum free fractions were always higher. The relation between the OF and serum concentrations was also evaluated by regression analysis and determination of slopes and correlation coefficients. For all measured relations, there was a statistically significant relation between the OF and serum concentrations. The degree of drug protein binding was in agreement with literature. The aripiprazole, duloxetine, pipamperone, pregabalin, and promethazine concentrations in ultrafiltrated serum were not possible to measure because of low concentrations and nonspecific binding.

CONCLUSIONS

Despite a strong statistical correlation between OF and serum concentrations observed for most of the studied substances, it is still evident that OF concentrations cannot simply substitute serum/plasma as therapeutic drug monitoring specimen, but rather be considered as a unique specimen. We believe that OF is a promising matrix especially for compliance testing in psychiatry settings. The Greiner Bio-One device used in this study provides a sampling procedure that offers advantages over the available alternatives.