Skopp G.^*, Poetsch L.^**

^* Institute of Legal Medicine, Voßstr. 2, 69115 Heidelberg, Germany
^** Institute of Legal Medicine, Am Pulverturm 3, 55131 Mainz, Germany

The illegal use of drugs poses a vast number of associated dangers on public health especially regarding road traffic and the ever-increasing number of impaired drivers. To identify these drivers more easily, roadside testing is based on non invasive sampling and screening methods as the initial method.
Body fluids such as saliva and perspiration for detection of drugs of abuse are becoming popular, because commercial devices for the collection of appropriate specimen are available now. The transfer mechanisms for the passage of drugs from blood into saliva are quite well elucidated but data on percutaneous drug delivery are rare.
The composition of saliva or skin secretions, a discussion of particular transport mechanisms as well as physiological and biochemical aspects of salivary glands, skin and its appendages are briefly presented. These theoretical reflections were confirmed by analyzing skin swabs and perspiration devices by GC/MS. The results were compared with findings obtained from skin testing by an immunological test procedure (Drugwipe^®). Saliva samples were collected using Salivette^® and were analyzed by Triage^® as well as by GC/MS. The samples were obtained from persons with a history of chronic or acute drug consumption. GC/MS analysis revealed the parent drugs to be the main analytes. Skin testing in chronic drug abusers proved to be always positive whereas a lag time (2-5 h) could be observed after acute consumption. Skin testing by the immunological test procedure was found to be inappropriate mainly because the system is based on metabolites and high LOD`s. In the initial phase after drug intake, especially after the oral and nasal route, high concentrations were present in saliva. In chronic drug abusers concentrations were comparatively low according to the calculated saliva/blood ratios of the particular substances.
Examples of analytical findings in skin swabs, saliva and blood samples for acute and chronic drug consumption are given to confirm biological data and to demonstrate that in roadside testing saliva should be favored over "sweat".