Pharmacokinetics of 11‐nor‐9‐Carboxy‐Δ 9 ‐Tetrahydrocannabinol (CTHC) After Intravenous Administration of CTHC in Healthy Human Subjects

After cannabis consumption there is only limited knowledge about the pharmacokinetic (PK) and metabolic properties of 11‐nor‐9‐carboxy‐Δ 9 ‐tetrahydrocannabinol (CTHC), which is formed by oxidative breakdown from Δ 9 ‐tetrahydrocannabinol (THC). Despite widely‐varying concentrations observed in smoking studies, attempts have been made to interpret consumption behavior with special regard to a cumulated or decreasing concentration of CTHC in serum. Ten healthy nonsmoking white male individuals received 5 mg CTHC intravenously over 10 min. Highest serum concentrations of CTHC were observed at the end of the infusion (336.8±61.7  μ g/l) followed by a quick decline. CTHC concentration could be quantified up to 96 h after administration, with a terminal elimination half‐life of 17.6±5.5 h. Total clearance was low (91.2±24.0 ml/min), with renal clearance having only a minor contribution (0.136±0.094 ml/min). This first metabolite‐based kinetic approach will allow an advanced understanding of CTHC PKs data obtained in previous studies with THC. Clinical Pharmacology & Therapeutics (2007) 82 , 63–69. doi: 10.1038/sj.clpt.6100199 ; published online 4 April 2007.