Impact of coca leaf flour candy consumption on cocaine and benzoylecgonine levels: The role of hygrine and cuscohygrine in distinguishing licit from illicit cocaine use

The consumption of coca leaf products, a traditional practice in several Latin American countries, raises forensic challenges in distinguishing legal consumption from illicit cocaine use. This study investigates the implications of consuming coca flour-based candies on drug detection thresholds in oral fluid (OF) and urine for drug-impaired driving (DUID) and workplace drug testing (WDT) contexts. Three commercial candy brands were analyzed, revealing significant variability in coca alkaloid content. Volunteers consumed these candies under controlled conditions, with biological samples collected at various intervals. Key analytes, including cocaine (COC), benzoylecgonine (BE), ecgonine methyl ester (EME), tropococaine (TRO) and cocaethylene (CE), were quantified alongside coca leaf-specific markers (cuscohygrine, cinnamoylcocaine, and hygrine). Analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring mode (MRM) transitions to ensure specificity. RESULTS: indicate that coca leaf markers (CUS, HYG) remain detectable after candy consumption, while traditional cocaine markers (COC, BE) exceeded international cutoffs for DUID and WDT in certain cases, particularly following ingestion of high-alkaloid brands. Coca-flour candies with alcoholic beverages produced detectable CE levels but never exceeded the cutoff values of 8 ng/mL in OF or 20 ng/mL in urine required by DUID guidelines. Analyte variability was influenced by candy brand, quantity consumed, and method of ingestion, with oral fluid showing prolonged detection when candies adhered to teeth. These findings emphasize the need to account for legal coca product consumption, as misinterpreted results could unjustly categorize consumers as illicit drug users, requiring nuanced approaches in forensic toxicology.