For many forensic toxicologists, studying the biological pathways of illicit drugs is important if offering interpretation to the submitting agents. One of the most common drugs seen by forensic toxicologists on a routine basis is cocaine. The pharmacokinetic profile of oral cocaine has not been fully characterized and prospective data on oral bioavailability is limited. In a recent paper published in Journal of Analytical Toxicology (doi: 10.1093/jat/bky007) by Marion A.Coe, set al., a within-subject study was performed to characterize the bioavailability and pharmacokinetics of oral cocaine. This study was performed using UCT’s most famous solid phase extraction (SPE) sorbent Clean Screen DAU®(ZSDAU020) to extract the compound and metabolites.
Fourteen healthy, inpatient participants (six males) with current histories of cocaine use were administered two oral doses (100 and 200 mg) and one intravenous (IV) dose (40 mg) during three separate dosing sessions. Plasma samples were collected for up to 24 h after dosing and analyzed for cocaine and metabolites by gas chromatography-mass spectrometry after SPE extraction and derivatization.
In this study, the pharmacokinetic parameters were calculated by non-compartmental analysis, and a two-factor model was used to assess for dose and sex differences. The mean ± SEM oral cocaine bioavailability was 0.32 ± 0.04 after 100 and 0.45 ± 0.06 after 200 mg oral cocaine. Volume of distribution (Vd) and clearance (CL) were both greatest after 100 mg oral (Vd = 4.2 L/kg; CL = 116.2 mL/[min kg]) compared to 200 mg oral (Vd = 2.9 L/kg; CL = 87.5 mL/[min kg]) and 40 mg IV (Vd = 1.3 L/kg; CL = 32.7 mL/[min kg]). Oral cocaine area-under-the curve (AUC) and peak concentration increased in a dose-related manner. AUC metabolite-to-parent ratios of benzoylecgonine and ecgonine methyl ester were significantly higher after oral compared to IV administration and highest after the lower oral dose. In addition, minor metabolites were detected in higher concentrations after oral compared to IV cocaine. Oral cocaine produced a pharmacokinetic profile different from IV cocaine, which appears as a rightward and downward shift in the concentration–time profile. Cocaine bioavailability values were similar to previous estimates. Oral cocaine also produced a unique metabolic profile, with greater concentrations of major and minor metabolites.
This study shows the power and efficiency of UCT’s world famous flagship sorbent Clean Screen® DAU when set to the task of evaluating the pharmacokinetics of cocaine. For more information regarding Clean Screen® DAU, visit https://sampleprep.unitedchem.com/products/spe/clinical-forensic/clean-screen-dau