title: In vitro stability of free and glucuronidated cannabinoids in blood and plasma following controlled smoked cannabis.
abstract: BACKGROUND
  Blood and plasma cannabinoid stability is important for test interpretation and is best studied in authentic rather than fortified samples.
  
  
  METHODS
  Low and high blood and plasma pools were created for each of 10 participants after they smoked a cannabis cigarette. The stabilities of Δ(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), cannabinol (CBN), THC-glucuronide, and THCCOOH-glucuronide were determined after 1 week at room temperature; 1, 2, 4, 12, and 26 (±2) weeks at 4 °C; and 1, 2, 4, 12, 26 (±2), and 52 (±4) weeks at -20 °C. Stability was assessed by Friedman test.
  
  
  RESULTS
  Numbers of THC-glucuronide and CBD-positive blood samples were insufficient to assess stability. In blood, 11-OH-THC and CBN were stable for 1 week at room temperature, whereas THC and THCCOOH-glucuronide decreased and THCCOOH increased. In blood, THC, THCCOOH-glucuronide, THCCOOH, 11-OH-THC, and CBN were stable for 12, 4, 4, 12, and 26 weeks, respectively, at 4 °C and 12, 12, 26, 26, and 52 weeks at -20 °C. In plasma, THC-glucuronide, THC, CBN, and CBD were stable for 1 week at room temperature, whereas THCCOOH-glucuronide and 11-OH-THC decreased and THCCOOH increased. In plasma, THC-glucuronide, THC, THCCOOH-glucuronide, THCCOOH, 11-OH-THC, CBN, and CBD were stable for 26, 26, 2, 2, 26, 12, and 26 weeks, respectively, at 4 °C and 52, 52, 26, 26, 52, 52, and 52 weeks, respectively, at -20 °C.
  
  
  CONCLUSIONS
  Blood and plasma samples should be stored at -20 °C for no more than 3 and 6 months, respectively, to assure accurate cannabinoid quantitative results.
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.
authors.forename: Karl B
authors.initials: KB
authors.lastname: Scheidweiler
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.|Aegis Sciences Corp., Nashville, TN.
authors.forename: David M
authors.initials: DM
authors.lastname: Schwope
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.|Aegis Sciences Corp., Nashville, TN.
authors.forename: Erin L
authors.initials: EL
authors.lastname: Karschner
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.
authors.forename: Nathalie A
authors.initials: NA
authors.lastname: Desrosiers
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.
authors.forename: David A
authors.initials: DA
authors.lastname: Gorelick
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD.
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Huestis
mesh_terms: D001800:Blood Specimen Collection; D002185:Cannabidiol / Q000097:blood; D002186:Cannabinoids / Q000097:blood*; D002187:Cannabinol / Q000031:analogs & derivatives / Q000097:blood; D013759:Dronabinol / Q000031:analogs & derivatives / Q000097:blood; D004355:Drug Stability; D005260:Female; D020719:Glucuronides / Q000097:blood*; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000097:blood*; D010949:Plasma; D015813:Substance Abuse Detection
chemical_list: D002186:Cannabinoids; D020719:Glucuronides; D002185:Cannabidiol; C053947:11-hydroxycannabinol; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol; D002187:Cannabinol