CBD Stability in Authentic Blood Had Very Limited Quantifiable Data
Only one participant had baseline blood CBD above the study’s quantification limit. The CBD stability observation was therefore much narrower than a ten-person CBD stability validation.
The overall study size was not the analyte-specific size
The investigators collected authentic blood and plasma after controlled cannabis smoking from ten participants and prepared individual low- and high-THC pools. Most blood CBD values were below the 1.2 microgram-per-liter quantification limit. For the one quantifiable participant, CBD remained within 20% of baseline for one week at room temperature and twelve weeks at refrigerated and frozen temperatures.
Sparse measurable data limit inference
Those observations are useful, but the number of participants contributing to a CBD stability estimate matters. Below-limit values do not provide the same quantitative information as measurable concentrations followed over time. Nor does a nonsignificant or uncomputable group comparison establish that CBD is stable across every relevant concentration.
Apply the result to matching conditions
A claim about stored CBD should identify matrix, initial concentration, container, temperature and duration. The study used authentic specimens after a specific smoking exposure; it was not a broad high-dose CBD formulation experiment. Its limited blood CBD data neither prove that another sample degraded nor establish a universal shelf life. The chemical stability question also does not measure the participant’s clinical response or impairment.
Related analysis: free metabolite changes during specimen storage.
Research cited
Scheidweiler and colleagues (2013). In Vitro Stability of Free and Glucuronidated Cannabinoids in Blood and Plasma Following Controlled Smoked Cannabis. DOI: 10.1373/clinchem.2012.201467.
