[Cannabinoid content in seized hashish joints from Castilla y León (Spain)].

Background: Cannabis, in both its herbal form and resin-derived products, is the most widely consumed illicit drug worldwide. This study aimed to determine the potency and dosage of the primary cannabinoids present in cannabis resin from joints circulating in the region.

Methods: A descriptive study was conducted on seized joints confiscated by law enforcement agencies in the Autonomous Community of Castilla y León (Spain) between 2017 and 2020. Gross (whole joint) and net (filler) weights were recorded. Gas chromatography was used to quantify cannabinoids delta-9-tetrahydrocannabinol, cannabidiol, and cannabinol. Potency (percentage content) and dosage (mg) were calculated and bioavailability was estimated at 10% and 25%.

Results: A total of 639 joints containing a mixture of cannabis resin and tobacco were analyzed (34.3% of confiscated samples). Both gross and net weights showed a decreasing trend over time (6.5-8.5%). Median potency values for delta-9-tetrahydrocannabinol, cannabidiol, and cannabinol were 7.58%, 0.62%, and 0.60%, respectively, while corresponding dosages were 57.04 mg, 4.57 mg, and 4.46 mg. Overall potency and dosage declined across the study period for THC (13.5%), CBN (73%) and CBD (52-67%).

Conclusions: The delta-9-tetrahydrocannabinol potency and dosage found in confiscated cannabis resin joints during the study period were higher than those typically reported for herbal cannabis joints, suggesting greater user exposure and increased potential health risks.