Accumulation of amphetamine in hair after contact with street amphetamine

Abstract

Drugs and drug metabolites can be incorporated into hair in different ways. In addition to passive diffusion from blood and accumulation from sweat, sebum and surrounding tissues, substances can be incorporated into hair through external contamination. Still, little is known about the effects of external contamination of hair with amphetamine. Amphetamine is a commonly used illegal drug and usually applied nasally. Handling and physical contact with powder containing amphetamine can easily lead to direct or indirect contact with hair, which might lead to positive hair results even without consumption. The aim of this study was to elucidate the impact of external contaminations through contact with amphetamine on hair analysis results. 25 subjects simulated the handling of amphetamine in a realistic manner over a short period of time that would be expected in a typical consumption setup. A hair and a urine sample were collected before the start of the study to rule out previous amphetamine abuse or external contamination. One gram of street amphetamine containing approximately 16% amphetamine sulfate was handed out to a total number of 15 participants. Under supervision the subjects prepared several lines of amphetamine for nasal consumption using personal items like credit cards and banknotes. Another group of 10 participants received 10 g of street amphetamine and packaged it into 10 bags, each containing approximately 1 g of powder. After the handling of amphetamine, hands were not be washed for 3 h. The experimental procedure was repeated on five consecutive days. Further hair and urine samples were taken at the fifth day and again after four and eight weeks. The samples taken at the Institute of Forensic Medicine in Freiburg were submitted to amphetamine analysis. The analysis comprised a washing procedure (water, acetone and petroleum ether), overnight methanolic extraction, subsequent solid phase extraction and LC-MS/MS detection of amphetamine enantiomers. Although consumption could be excluded, the handling of street amphetamine led to accumulation of amphetamine in hair. Amphetamine was detected in relatively high concentrations directly after the exposition to amphetamine, but was still detectable four and eight weeks later. As expected washing of the hair samples was not sufficient to remove external amphetamine contamination. Obviously, amphetamine was incorporated and accumulated in the hair matrix via diffusion, preventing rapid wash-out during the decontamination procedure. External contamination of hair with amphetamine cannot be efficiently removed by a hair washing procedures prior to hair analysis. The interpretation of positive amphetamine results in hair must be carried out with caution as “false positive” results might occur. Further studies should look more closely at the quantity of amphetamine enantiomers incorporated into hair by other routes (blood stream, sweat, sebum) to improve the basis of interpretation for hair analysis results.