Toxtyper Screening of Saliva as an Alternative Matrix for General Unknown Screening of Drugs of Abuse

Markus Meyer, Bruker Daltonik GmbH, Bremen, Germany
Dirk Wunderlich, Bruker Daltonik GmbH, Bremen, Germany
Stefanie Lohrmann, Bruker Daltonik GmbH, Bremen, Germany
Michael Boettcher, Bruker Daltonik GmbH, Bremen, Germany

Introduction :
Background: Drug screening in patients undergoing substitution or abstinence therapy is predominantly performed with urine samples using immunochemical methods. In order to prevent manipulation of the samples and to ensure their authenticity, sampling under visual inspection is required. In recent years screening with the usual tests became no longer sufficient in many cases. Therefore, GC/MS was increasingly used for general unknown screening. In comparison to urine, saliva is much easier to gain under supervision. In the context of this study, the possibility of general unknown screening in saliva samples in combination with a LC-MSⁿ library search approach (Toxtyper) is reported.

Methods :
250 saliva samples for routine drug screening of patients mainly from substitution or abstinence therapy (62% male, 27% female, 11% unspecified) were further investigated after anonymization. The samples were collected using the Greiner Bio-One Saliva Collection System pH 4.2 according to the manufacturer's instructions.

An aliquot of the saliva sample was mixed with different internal standards and 1:20 concentrated after protein precipitation and liquid-liquid extraction. The samples were measured with two different chromatographic methods using an LC-MSⁿ ion trap (Toxtyper, Bruker). The respective mass spectra were automatically evaluated with the spectral library of Bruker and the Maurer / Weber / Wissenbach "LC-MSⁿ Library of Drugs, Poisons and their Metabolites" (Wiley-VCH, 2014).

Results :
The detected compounds were categorized into the following categories: amphetamines, benzodiazepines, cocaine, opiates, opioids/analgesics, antidepressants, beta-blockers, neuroleptics and others. THC is poorly detectable in saliva with this approach, and was not considered.

Amphetamines: In 10 patients (4%) 4 different amphetamines could be detected 13 times. Benzodiazepines: 9 different benzodiazepines were detected 61 times in 36 patient samples (14%). Cocaine: Cocaine or its metabolite was positive in 14 patients (6%). Opiates: 4 different opiates were detected at least once in 31 patients (12%). Opioids/analgesics: 9 different substances were detected 69 times in 63 patients (25%). Of this amount, paracetamol 36 times and naloxone 8 times were detected. Antidepressants: In 81 samples (32%), 14 different antidepressants were 101 times positive. ß-blocker: In 18 patients (7%), 7 different substances could be detected 21 times. Neuroleptics: In 55 patients (22%) 12 different neuroleptics were detected 70 times. Other compounds: 37 additional compounds of toxicological or forensic relevance could be detected 91 times in 75 patient samples (30%).

In total 97 different compounds could be detected. Methadone was detected in 135 patients (54%) and buprenorphine in 55 patients (22%). Twelve samples (5%) were completely negative for xenobiotics.

Conclusion: 99 different substances were detected a total of 686 times. An indeterminate percentage of these had certainly been prescribed by the doctor and should not be classed as substance abuse. A total of 95% of the samples were positive for at least one substance. Thus the GU in saliva samples appears to be a good alternative to the GU in urine samples.

Novel Aspect:
First application of systematic saliva screening as alternative matrix for drugs screening in combination with the automated Toxtyper LC-MSn library search approach.