Institute of Clinical Chemistry, Bogenhausen City Hospital;
* Institute of Legal Medicine, University of Munich;
** MRI Clinical Toxicology, Technical University Munich, Germany

130 saliva samples (from 34 patients) were obtained from the oral cavity using a new developed collection device. Clin Rep^® (Recipe, Munich GER) consists of a cotton roll treated with 1% citric acid and a centrifugation vial with a filter inset. Urine was extracted by liquid extraction using Toxilab A vials (DRG, Marburg GER). Saliva samples were prepared with chromabond drug^® columns (Macherey-Nagel, Düren GER). Retention times were verified by deuterated standards.

From a total of 130 samples 9 urines were positive for cocaine metabolite above 100 ng/ml benzoylecgonine by FPIA. GC/MS identified benzoylecgonine in 7 samples, cocaine once and methylecgonine once in these samples. In saliva in all 9 corresponding specimens cocaine itself was detectable with a limit of detection of 10 ng/ml. By FPIA, however, no positive results were found. The other 121 samples were negative with urine and saliva as well. Cocaine was detectable in saliva for up to 4 days (maximal) after withdrawal of the drug.

Although analysis of cocaine in saliva requires sample extraction, derivatisation and analysis by GC/MS, saliva as sample material has many advantages: Saliva can easily be collected under supervision and therefore sample adulteration seems to be difficult. Patients do not feel disturbed in their privacy and the sample is obtainable at any time.