A systematic review of quantitative analysis of cannabinoids in oral fluid

Cannabis sativa L. is a substance widely used around the world for recreational and medicinal purposes. Oral fluid has been investigated as an alternative biological matrix for demonstrating the illegal use of cannabis, particularly in situations where its recent use needs to be identified. In the last two decades, many methods have been developed to detect and quantify cannabinoids in oral fluid, especially for Δ⁹ -tetrahydrocannabinol, the primary psychoactive substance of cannabis. However, some aspects must be considered in the use of these techniques, such as cannabinoids recoveries or extraction efficiency from different oral fluid collection devices/containers. Pharmacokinetic studies have shown that the presence of minor cannabinoids and metabolites in the analysis of oral fluid may be valuable in interpreting tests, which indicates the need to improve the sensitivity of detecting low concentrations. The aim of this review is to summarize and to describe the methodologies for the quantitative analysis of cannabinoids in oral fluid that have previously been investigated. A systematic search for articles was performed of four different databases, using the descriptor "cannabinoids and oral fluid". Forty-seven studies that examined quantitative methods were identified. The analytical data described in these articles, including oral fluid collection, sample preparation, cannabinoids recovery and extraction efficiency, detection instruments, and quantification limits, were analyzed. The discussion of these particular features of cannabinoid analysis in oral fluid could help to improve or to develop methods for use in Forensic Toxicology.