The analysis and detection of new psychoactive substances in biological matrices

Nisbet, Lorna A. (2015) The analysis and detection of new psychoactive substances in biological matrices. PhD thesis, University of Glasgow.

Abstract

New psychoactive substances (NPSs) have appeared on the recreational drug
market at an unprecedented rate in recent years. Many are not new drugs but
failed products of the pharmaceutical industry. The speed and variety of drugs
entering the market poses a new complex challenge for the forensic toxicology
community. The detection of these substances in biological matrices can be
difficult as the exact compounds of interest may not be known. Many NPS are
sold under the same brand name and therefore users themselves may not know
what substances they have ingested.

The majority of analytical methods for the detection of NPSs tend to focus on a
specific class of compounds rather than a wide variety. In response to this, a
robust and sensitive method was developed for the analysis of various NPS by
solid phase extraction (SPE) with gas chromatography mass spectrometry (GCMS).
Sample preparation and derivatisation were optimised testing a range of
SPE cartridges and derivatising agents, as well as derivatisation incubation time
and temperature. The final gas chromatography mass spectrometry method was
validated in accordance with SWGTOX 2013 guidelines over a wide concentration
range for both blood and urine for 23 and 25 analytes respectively. This included
the validation of 8 NBOMe compounds in blood and 10 NBOMe compounds in
urine. This GC-MS method was then applied to 8 authentic samples with
concentrations compared to those originally identified by NMS laboratories.

The rapid influx of NPSs has resulted in the re-analysis of samples and thus, the
stability of these substances is crucial information. The stability of mephedrone
was investigated, examining the effect that storage temperatures and
preservatives had on analyte stability daily for 1 week and then weekly for 10
weeks.

Several laboratories identified NPSs use through the cross-reactivity of these
substances with existing screening protocols such as ELISA. The application of
Immunalysis ketamine, methamphetamine and amphetamine ELISA kits for the
detection of NPS was evaluated. The aim of this work was to determine if any
cross-reactivity from NPS substances was observed, and to determine whether
these existing kits would identify NPS use within biological samples. The cross-
reactivity of methoxetamine, 3-MeO-PCE and 3-MeO-PCP for different
commercially point of care test (POCT) was also assessed for urine.

One of the newest groups of compounds to appear on the NPS market is the
NBOMe series. These drugs pose a serious threat to public health due to their
high potency, with fatalities already reported in the literature. These
compounds are falsely marketed as LSD which increases the chance of adverse
effects due to the potency differences between these 2 substances. A liquid
chromatography tandem mass spectrometry (LC-MS/MS) method was validated in
accordance with SWGTOX 2013 guidelines for the detection for 25B, 25C and 25I-NBOMe in urine and hair.

Long-Evans rats were administered 25B-, 25C- and 25I-NBOMe at doses ranging
from 30-300 µg/kg over a period of 10 days. Tail flick tests were then carried out
on the rats in order to determine whether any analgesic effects were observed
as a result of dosing. Rats were also shaved prior to their first dose and reshaved
after the 10-day period. Hair was separated by colour (black and white)
and analysed using the validated LC-MS/MS method, assessing the impact hair
colour has on the incorporation of these drugs. Urine was collected from the
rats, analysed using the validated LC-MS/MS method and screened for potential
metabolites using both LC-MS/MS and quadrupole time of flight (QToF)
instrumentation.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: NPS, New psychoactive substances, NBOMes, Cathinones, Forensic Toxicology, GC-MS.
• Subjects: R Medicine > RA Public aspects of medicine > RA1001 Forensic Medicine. Medical jurisprudence. Legal medicine
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Supervisor's Name: Wylie, Dr. Fiona and Scott, Dr. Karen S.
• Date of Award: 2015
• Depositing User: Miss Lorna Agnes Nisbet
• Unique ID: glathesis:2015-7213
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 16 May 2016 09:01
• Last Modified: 17 May 2016 08:10
• URI: https://theses.gla.ac.uk/id/eprint/7213