Single-hair analysis of zolpidem on the supposition of its single administration in drug-facilitated crimes

Little information is available on the amounts of hypnotics incorporated into hair after a single administration and about effective analytical procedures to document cases like drug-facilitated sexual assaults. To obtain basic information, single-hair specimens from a volunteer who took a single dose of 10-mg zolpidem (ZP) were analyzed by a newly established liquid chromatography-tandem mass spectrometry procedure, using a one-pot pulverization extraction method. The detection limit of ZP was 50 fg/2-cm single hair, and ZP in each segment was determined for the single black hair specimens (n = 15). ZP was detectable in 14 hairs (positive for all the proximal 0-2 cm segments, negative for all 2-4 cm segments), but was not detected in a single hair (probably in the telogen stage). The amounts of ZP detected in each positive 2-cm segment of single hair ranged from 27 to 63 pg (average 43 pg). The estimated total incorporation of ZP in the scalp hair (black hair similar to 110,000 strands) was about 4.7 mu g, which corresponds to about 0.06 % of the single 10-mg dose (8.03 mg as free ZP). In addition, the direct detection of single-dose ZP incorporated in hair and its imaging were successfully achieved by matrix-assisted laser desorption ionization-mass spectrometry. It is suggested that a combination of these methodologies will provide the highest-level evidence to document such exposure to a hypnotic drug.