Development and validation of an LC-MS analytical method for the quantification of cannabinoids in blood plasma of medicinal CBD users

The Cannabis sativa L. plant has been used worldwide for medicinal purposes for thousands of years and is a rich source of bioactive compounds, such as cannabinoids. Among them, Δ 9 -THC and CBD stand out for their therapeutic effects, with applications in pain relief, and the treatment of several health conditions. CBD, in particular, has shown potential in the treatment of knee osteoarthritis, relieving pain and improving patient mobility [ 1 ]. Thus, this study aims to establish an analytical method for the quantification of CBD, CBN, Δ 9 -THC, CBG, 11-OH-THC and 11-COOH-THC in 40 blood plasma samples, contributing to better dosage control and monitoring of cannabinoid therapy. To evaluate the selectivity of the method, a matrix effect study was conducted, in which a t-test indicated that the slopes of the calibration curve did not present statistically significant differences for the cannabinoids analyzed. The calibration curves covered a concentration range of 0.0025 to 0.25 μg mL −1 , demonstrating good linearity, with correlation coefficients (R 2 )≥0.9855. The limits of quantification (LOQ) ranged from 4.10×10 −2 to 2.14×10 −2 μg mL −1 , while the limits of detection (LOD) were between 1.19×10 −2 and 9.42×10 −3 μg mL −1 . The results indicate that the developed method presents good selectivity and linearity, together with LOD and LOQ values appropriate for biological matrix analysis. The absence of matrix effect reinforces its reliability. However, the validation process is still ongoing, with precision and accuracy assessments, critical steps to ensure the robustness and applicability of the method in routine analytical use. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany