Instability and poor recovery of cannabinoids in urine, oral fluid, and hair.

Cannabinoids including, but not limited to Δ9-tetrahydrocannabinol, 11-hydroxytetrahydrocannabinol, and (-)-11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid are known to toxicologists and synthetic chemists as difficult compounds because they are subject to numerous degradative pathways. It is the purpose of this short review article to discuss common pathways that result in the disappearance of cannabinoids - such as conjugate formation, adsorption to surfaces, chemical reactions, microbial action, thermal decomposition, chemical bonding, photosensitivity, sample handling, analytical methodology, and micelle trapping - and to point out possible ways to avoid such degradation.