SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

M6
MONITORING DRUG USE THROUGH SEGMENTAL HAIR ANALYSIS. A THREE YEAR
CASE STUDY.
Karen S. Scott*, Kerri-Ann Hoy: Department of Forensic Science and Chemistry, AngJia Polytechnic
University, Cambridge
Segmental analysis of hair for the determination of past drug use is an area which receives mixed views
within the field of Forensic Toxicology. The aim of this study was to ascertain if an accurate pattern of
drug use can be predicted by the segmental analysis ofa length of hair. The hair sample (33cm length) was
obtained from a 47 year old male with a known history of use of three types of medication. Atenolol
(IOOmg) was taken as required; diazepam (3x 5mg) was taken as required and dihydrocodeine (3 x 30 mg)
was taken daily. All three drugs had been prescribed over a period of9 years following a serious injury.
The hair was cut into eleven 3 cm sections each representing an approximate period of three months
(assuming a hair growth rate of I cm/month). The segments were prepared for extraction by washing and
cutting. Blank hair was obtained from a subject known not to have used any of the drugs under
investigation and similarly prepared. Triplicate aliquots (20 mg) of the hair were subjected to overnight
acidified methanolic digestion along with standards and blanks. Following digestion the samples were
filtered, evaporated to dryness, derivatised using BSTF A 1% TMCS and analysed by GCIMS in the SIM
mode.
Analysis of atenolol in the hair segments showed a variable pattern of use. No accurate record of atenolol
use was obtained other than an increased use for short periods of time 9 and 18 months prior to sampling.
The highest concentration of atenolol in the hair segments was obtained in segment three (corresponding to
6-9 months hair growth). A slight increase in the levels measured in segment six (corresponding to 15-18
months) was also observed.
The analysis of diazepam in hair showed an overall increase of drug in hair from the proximal end to the
distal end. It is known that the subject decreased the frequency of diazepam use in the 18 months prior to
sampling which is consistent with the decreased concentrations in these hair sections. However there is a
threefold increase in the amount of diazepam detected between segment six (15-18 months) and segment II
(30-33 months). No drug use history of diazepam is available for this period.
Finally, the analysis ofdihydrocodeine for which the full drug history was known (90 mg/day for 9 years)
yielded extremely interesting results. If no environmental issues (e.g. UV exposure, washing) affect the
amount of drug in hair then we would expect the levels in the proximal and distal segments to give the
same concentration. However a decrease of approximately 90% in the level of dihydrocodeine detected
was observed (r2 0.77).
This study demonstrates that hair analysis can be used to detect drugs which were taken several years ago.
More work is required to determine the exact relevance of history evaluation through segmental analysis
but the results for dihydrocodeine indicate that this is not a futile exercise. The importance of obtaining a
full drug use history from subjects participating in studies of this type is highlighted in the analysis of both
atenolol and diazepam where gaps in the history meant that a full interpretation of the results could not be
carried out.
Keywords: Segmental Analysis, Drug Use History
Page 289