title: Postmortem redistribution of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH).
abstract: BACKGROUND
  Postmortem redistribution (PMR), a well-described phenomenon in forensic toxicology for certain drugs, can result in increased central blood concentrations relative to peripheral blood concentrations. Δ(9)-tetrahydrocannabinol (THC), the primary psychoactive component in cannabis or marijuana, is the illicit substance most commonly implicated in driving under the influence of drugs (DUID) cases and fatally-injured drivers. No investigation of PMR of THC in human blood has been reported to date.
  
  
  METHODS
  Matched heart and iliac postmortem blood specimens were collected from 19 medical examiner cases (16 Males, 3 Females) with positive cannabinoid urine immunoassay screens. THC, its equipotent metabolite 11-hydroxy-THC (11-OH-THC) and non-psychoactive metabolite 11-nor-9-carboxy-THC (THCCOOH) were quantified by two-dimensional gas chromatography-mass spectrometry with cryofocusing, with 0.5 ng/mL limits of quantification (LOQ) for all analytes.
  
  
  RESULTS
  10 cases had quantifiable THC and 11-OH-THC; THCCOOH was present in all 19. Median (range) heart:iliac blood ratios were 1.5 for THC (range: 0.3-3.1); 1.6 for 11-OH-THC (range: 0.3-2.7); and 1.8 for THCCOOH (range: 0.5-3.0).
  
  
  CONCLUSIONS
  Cannabinoids, in general, exhibited a mean and median central:peripheral (C:P) concentration ratio of less than 2 following death. A trend was observed for greater PMR with increasing postmortem interval between death and sampling. To our knowledge, these are the first data on THC PMR in humans, providing important scientific data to aid in the interpretation of postmortem cannabinoid concentrations in medico-legal investigations.
authors.affiliation: Department of Emergency Medicine, SUNY Upstate Medical University, Syracuse, NY 13210, United States. mholland@glensfallshosp.org
authors.forename: Michael G
authors.initials: MG
authors.lastname: Holland
authors.forename: David M
authors.initials: DM
authors.lastname: Schwope
authors.forename: Robert
authors.initials: R
authors.lastname: Stoppacher
authors.forename: Shane B
authors.initials: SB
authors.lastname: Gillen
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Huestis
mesh_terms: D001344:Autopsy; D001800:Blood Specimen Collection / Q000379:methods; D002186:Cannabinoids / Q000097:blood* / Q000737:chemistry; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000097:blood* / Q000737:chemistry; D005260:Female; D053593:Forensic Toxicology / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D011180:Postmortem Changes; D012494:Sampling Studies; D018709:Statistics, Nonparametric; D015813:Substance Abuse Detection / Q000379:methods
chemical_list: D002186:Cannabinoids; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol