Cocaine disposition in saliva following intravenous, intranasal, and smoked administration

Saliva concentrations of cocaine, benzoylecgonine, ecgonine methyl ester, and anhydroecgonine methyl ester were measured by gas chromatography- mass spectrometry in six healthy male subjects following cocaine administration by the intravenous, intranasal, and smoked routes of administration. Cocaine appeared in saliva rapidly following all routes of administration. Saliva/plasma (S/P) ratios were generally greater than 1, and there was evidence of moderate to extreme contamination of saliva by cocaine immediately following intranasal and smoked routes of administration. Contamination of the oral cavity and saliva cleared rapidly. Saliva obtained 2 h after dosing appeared to be free of contamination and demonstrated S/P ratios comparable with intravenous administration. Benzoylecgonine and ecgonine methyl ester concentrations were consistently low and were only comparable with cocaine concentrations at times when cocaine concentrations had declined to below 100 ng/mL. Anhydroecgonine methyl ester was detectable in saliva following smoked drug administration, but it was quickly cleared. Terminal half-life estimates for cocaine administered by the intranasal and smoked routes were significantly shorter in saliva compared with those measured in plasma. Half-life estimates following intravenous administration tended to be lower for saliva than plasma, but the differences were not significant. The duration of pharmacologic effects was generally the same as or shorter than detection times of cocaine in plasma and saliva. Overall, the study demonstrated the usefulness of saliva as a test matrix for the detection and measurement of cocaine following administration by different routes of administration.