Partition coefficient, blood to plasma ratio, protein binding and short-term stability of 11-nor-Delta(9)-carboxy tetrahydrocannabinol glucuronide

Forensic Sci Int. 2002 Mar 28;126(1):17-23. doi: 10.1016/s0379-0738(02)00023-3.


11-Nor-Delta(9)-carboxy tetrahydrocannabinol glucuronide (THCCOOglu) is a major metabolite of tetrahydrocannabinol in blood. Despite its mass spectrometric identification already in 1980, further physicochemical data of THCCOOglu have not been established. Therefore, the octanol/buffer partition coefficient P and the blood to plasma ratio b/p for THCCOOglu concentrations of 100 and 500ng/ml were investigated. Protein binding of the glucuronide was established from spiked albumin solutions at a level of 250ng/ml as well as from authentic samples. The data were compared to those of 11-nor-Delta(9)-carboxy tetrahydrocannabinol (THCCOOH). In addition, the short-term stability of THCCOOglu in plasma at different storage temperatures was studied. Analysis was performed by LC/MS/MS. The glucuronide partition coefficient P (mean: 17.4 and 18.0 for 100 and 500ng/ml, respectively) was unexpectedly lipophilic at pH 7.4. Its blood to plasma ratios averaged 0.62 and 0.68 at 100 and 500ng/ml, respectively. THCCOOglu was highly reversibly bound to albumin (mean: 97%), and the mean fraction bound did not differ from that determined from authentic samples. THCCOOglu degraded even at a storage temperature of 4 degrees C and THCCOOH was identified as a major decomposition product.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Specimen Collection
  • Dronabinol / administration & dosage*
  • Dronabinol / analogs & derivatives*
  • Dronabinol / analysis*
  • Dronabinol / blood
  • Drug Stability
  • Forensic Medicine
  • Glucuronides / analysis*
  • Glucuronides / blood
  • Humans
  • Mass Spectrometry
  • Protein Binding


  • Glucuronides
  • 11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid
  • Dronabinol