Institut de Médecine Légale, 11 rue Humann, 67085 Strasbourg, France

In order to verify if normal hygiene practices with Cannabio^® shampoo can cause positive hair results for cannabinoids, 3 subjects daily washed their hair with this shampoo during two weeks. After this period, hair specimens were collected and extracted as described in our previously published procedure (Cirimele et al., J. Anal. Tox., 20, 1996, 13-16). In the 3 hair specimens, THC, CBD and CBN were never detected within their respective limits of detection 0.1, 0.02 and 0.01 ng/mg. We concluded that the use of Cannabio^® shampoo during normal hygiene practices cannot be considered as a source of potential contamination of hair.

In a second experiment, drug-free hair specimens (200 mg) were incubated in 10 ml water/Cannabio^® shampoo (20:1, v/v) for 30 minutes, 2 and 5 hours, respectively. After incubation, hair strands were washed with water and separated into two portions. One part was extracted directly, the second was decontaminated with methylene chloride and then extracted. After an incubation period of 30 minutes, the analysis of hair by GC/MS did not revealed the presence of THC, CBD and CBN either with or without decontamination. After an incubation period of 2 hours, specimens tested positive for CBD (0.113 ng/mg without decontamination and 0.100 ng/mg after decontamination) and CBN (0.019 ng/mg without decontamination and 0.018 ng/mg after decontamination). After an incubation period of 5 hours, specimens tested positive for CBD (0.247 ng/mg without decontamination and 0.135 ng/mg after decontamination) and CBN (0.021 ng/mg without decontamination and 0.020 ng/mg after decontamination). THC was never detected.

In conclusion, extensive but unrealistic use of Cannabio^® shampoo can produce positive analyses in drug-free hair for CBD and CBN but not for the primary psychoactive drug THC.