TY - JOUR
T1 - Stability of drugs of abuse in synthetic oral fluid investigated using a simple “dilute and inject” method of analysis
AU - Gavrilović, Ivana
AU - Musenga, Alessandro
AU - Wolff, Kim
AU - Woffendin, Alison
AU - Smart, Andrew
AU - Gong, Fan
AU - Harding, Duncan
AU - Cowan, David
N1 - Funding Information:
Funding was received from the Home Office, Centre for Applied Science and Technology HOS/13/038: Stability Testing of Drug Solutions. Open access funding enabled and organized by Projekt DEAL.
Publisher Copyright:
© 2022 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd.
PY - 2022/8
Y1 - 2022/8
N2 - Human oral fluid is well established as a matrix for drug screening, particularly in the workplace. The need to synthesise synthetic oral fluid (SOF) has been recognised in order to overcome human oral fluid's composition variability. We have used SOF spiked with six common drugs of abuse or their primary metabolites: morphine, amfetamine, benzoylecgonine, cocaine, diazepam, and (−)-Δ9-tetrahydrocannabinol (THC) in order to assess the suitability of this matrix for quality assurance purposes. For confirmation of a drug screening test, controls and spiked standards are normally required. All our analytes were detected by LC–MS/MS using a quick and easy “dilute and inject” sample preparation approach as opposed to relatively slower solid-phase extraction. The limit of detection (LOD) was 10 ng/ml for diazepam and THC and 5 ng/ml for morphine, amfetamine, benzoylecgonine and cocaine. Validation results showed good accuracy as well as inter- and intra-assay precision (CV [%] < 5). Our work highlighted the importance of adding Tween® 20 to the SOF and calibrants to reduce losses when handling THC. Furthermore, drug stability was tested at various temperatures (5°C, 20°C and 40°C), for a number of days or after freeze–thaw cycles. Recommendations regarding storage are provided, the spiked SOF being stable at 5°C for up to 1 week without significant drug concentration loss.
AB - Human oral fluid is well established as a matrix for drug screening, particularly in the workplace. The need to synthesise synthetic oral fluid (SOF) has been recognised in order to overcome human oral fluid's composition variability. We have used SOF spiked with six common drugs of abuse or their primary metabolites: morphine, amfetamine, benzoylecgonine, cocaine, diazepam, and (−)-Δ9-tetrahydrocannabinol (THC) in order to assess the suitability of this matrix for quality assurance purposes. For confirmation of a drug screening test, controls and spiked standards are normally required. All our analytes were detected by LC–MS/MS using a quick and easy “dilute and inject” sample preparation approach as opposed to relatively slower solid-phase extraction. The limit of detection (LOD) was 10 ng/ml for diazepam and THC and 5 ng/ml for morphine, amfetamine, benzoylecgonine and cocaine. Validation results showed good accuracy as well as inter- and intra-assay precision (CV [%] < 5). Our work highlighted the importance of adding Tween® 20 to the SOF and calibrants to reduce losses when handling THC. Furthermore, drug stability was tested at various temperatures (5°C, 20°C and 40°C), for a number of days or after freeze–thaw cycles. Recommendations regarding storage are provided, the spiked SOF being stable at 5°C for up to 1 week without significant drug concentration loss.
KW - drug stability
KW - LC–MS/MS
KW - synthetic OF
KW - “dilute and inject”
UR - http://www.scopus.com/inward/record.url?scp=85130480036&partnerID=8YFLogxK
U2 - 10.1002/dta.3279
DO - 10.1002/dta.3279
M3 - Article
C2 - 35514245
AN - SCOPUS:85130480036
SN - 1942-7603
VL - 14
SP - 1482
EP - 1490
JO - Drug Testing And Analysis
JF - Drug Testing And Analysis
IS - 8
ER -