Influence of bleaching on stability of benzodiazepines in hair

In order to study the influence of hair bleaching on benzodiazepines concen trations, hair was treated with a bleaching product (Poly Blonde, Schwarzko pf & Henkel) for 20 min. The treated hair specimen was obtained from a pers on who died after an overdose of several illicit drugs associated with benz odiazepines. Bleached and non bleached hair were washed (acetone and water) , pulverised and then incubated for 2 h in a thioglycolic solution. In the extracts obtained by solid-phase extraction on C-18 columns, the different drugs with the corresponding deuterated standards were derivatized and dete rmined by GC-MS in a SLM mode. These results show that the concentrations o f all the drug detected decreased in bleached hair in comparison with non t reated hair. Whereas the diminution was less important for cocaine and benz oylecgonine (decrease of 24.6 and 36.4%, respectively), concentrations for codeine, 6-monoacetylmorphine and morphine decreased more significantly (de crease of 57.5, 88.6 and 67.4%, respectively) as well as those of diazepam, nordazepam and 7-aminoflunitrazepam (decrease of 39.7, 67.7 and 61.8%, res pectively), The results in this study agree with those of other authors tha t bleaching affects the stability of cocaine and opiates incorporated in ha ir. These findings also point out that bleaching influences the stability o f entrapped benzodiazepines in hair. Finally, these results reconfirm that it is very important to consider the cosmetic history of a hair sample in t he interpretation of hair analysis results. (C) 2000 Elsevier Science Irela nd Ltd. All rights reserved.