Hair Analysis And Evaluation Of Drugs In Drug-facilitated Crimes

The increase in reports of drug-facilitated crimes (sexual assaults, robbery) has caused alarm in the general public. Drugs involved can be single dosage, short-acting, low concentration and rapid absorption and metabolism. Besides, most of these substances possess amnesic properties and therefore the victims are less able to accurately recall the circumstances under which the sexual offence occurred. Their blood and urine samples are usually unable to provide effective evidence of drug intake. To address a response to this important caveat, hair was suggested as a valuable specimen. Hair analysis can prolong the detection window and provide long-term information of drug abuse which plays an important role in drug-assisted criminal cases, and sometimes even become the only means to provide evidence.Based on the existing research results of hair segmentation analysis of a single dose and novel toxicology analysis techniques, zolpidem and gamma-hydroxybutyric acid (GHB)(different physical and chemical properties) were chosen as the research object. Volunteers experimental were carried out to study the incorporation and distribution of drugs in hair after a single dosage.The same dose of zolpidem was used to perform hair segmental analysis of different hair color between Chinese and Caucasian population. Hair samples were collected1month after administration of10mg zolpidem. The2cm segments near the root of black hair of healthy volunteers were135.0-554.6pg/mg (n=20), which were much higher than that of the Caucasian population. The study indicated that hair color and dose factors should be considered in drug auxiliary criminal cases.The GC-MS/MS method to determine GHB in hair was of high sensitivity, specificity, high accuracy, and the lower limit of quantification of GHB was0.05ng/mg. This was the first time to determine and evaluate the GHB concentration in hair. Four volunteers oral ingested1.5g GHB, and hair samples were collected for6weeks. After0.5cm segmentation hair analysis, only two volunteers pronounced peak concentration after4weeks, while the rest had no appreciable change. Due to physical and chemical properties of GHB, it is difficult for GHB to enter the hair. Besides, the presence of endogenous GHB as well make it hard to use segmental hair analysis when involved in drug assisted criminal cases.On the whole, this was the first time to study the incorporation and distribution of drugs of different physical and chemical properties in hair after a single dosage. Significant difference of segmental hair analysis and drug disposition was found between different drugs. The study indicated that it was important to accumulate data of each compound when dealing with drug-facilitated crimes. The above study can be used in drug-facilitated crimes to provide the basis for the interpretation.