Assessment of incorporation of drugs into hair, extraction and analysis techniques, and potential interferences with hair analysis for drug detection

Author: Caitlyn Rogers

Rogers, Caitlyn, 2018 Assessment of incorporation of drugs into hair, extraction and analysis techniques, and potential interferences with hair analysis for drug detection, Flinders University, College of Science and Engineering

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The analysis of drugs from hair samples can provide forensic toxicologists a great deal of information that cannot be gained through the analysis of blood and urine. Hair analysis is usually performed as a complementary technique to blood and urine analysis, but has the added advantage of having a greater detection window (months to years, compared to hours to days). This longer detection window allows for determination of chronic drug use, chronic poisoning, the monitoring of drug abstinence and obtaining a drug history. In forensic toxicology, hair analysis can be used in cases involving drug facilitated crimes (DFC’s) including drug-facilitated sexual assault, child protection and suspicious death. Despite this, there are no recognised standard methods for hair analysis. Methods of extracting the drugs from hair are of particular concern, and can vary significantly from lab to lab. Extraction generally involves an incubation step which can last for up to 18 hours. This lengthy extraction process can be a hindrance to case flow. Additional problems with the hair analysis can arise if the hair has been cosmetically treated after a drug has been consumed. Furthermore, authentic drugged hair samples (i.e. hair from a donor that has been administered drugs) should be used for method development and validation. However, it is difficult to acquire authentic hair samples with enough variety of drugs at high enough concentrations to use for this purpose. Artificially incorporating drugs into hair has been proposed for method development and R&D purposes involving hair analysis for drug detection. However, very little is understood about the underlying factors that influence the incorporation. For example, how does solvent affect the degree of drug incorporation into the hair shaft.

Research presented in this thesis examines alternative methods of extraction as a potential substitute for an 18-hour incubation process used for the analysis of hair, along with an investigation into the effects of cosmetic hair treatments on drug recovery. Finally, investigations into the preparation of artificially spiked hair samples for use in method development are presented.

Microwave-assisted extraction (MAE) into methanol resulted in extraction time being reduced, without the requirement for any change to the sample preparation process. The extraction time and temperature were optimised with the optimum conditions being microwaving for 2 hours at 70 °C for a 20 mg hair sample in 2 mL solvent. Other variables were unable to be studied, as the research was limited by the capacity of the microwave which could only irradiate one sample at a time.

The use of an ionic liquid composite (ILC) to disassemble the structure of hair prior to extraction was also assessed. There is has been no prior work published on the use of ionic liquids, or ionic liquid composites, for the digestion and extraction of drugs from hair. The ILC was shown to disassemble the hair structure, however the high temperatures required and the viscosity of the ILC are unsuitable for extraction and detection of drugs in forensic analysis. There is however, potential for this ILC to be used in the detection of heavy metals and other thermally stable compounds in hair.

The effects of three cosmetic hair treatment protocols on drug recovery and hair structure were investigated. These were i) Olaplex® treatment, ii) bleach treatment, and iii) a combined Olaplex® – bleach treatment program. Olaplex® is a recently released cosmetic hair treatment reported to repair hair by rebuilding disulphide bonds. Marketing suggests that it will reduce the damage caused by additional treatments such as bleaching. While there are many cosmetic treatments that have previously been assessed on their potential to interfere with drugs in the hair, Olaplex® has not yet been investigated. There also no reports on how the treatment affects the hair structurally, at a microscopic level. Results presented in this thesis show that the Olaplex® treatment did reduce the damage done to the hair, when compared to bleaching alone. However, this treatment did not reduce the amount of drug lost during bleaching treatments. It was also found through the use of FT-IR that hair that had been bleached could be differentiated from naturally blonde hair. However, this method could not detect Olaplex® on Olaplex® treated hair.

Finally, an investigation into how temperature, solvent ratios (of methanol and DMSO), and prior cosmetic treatment affect the artificial incorporation of drugs into hair. While there have been a small number of reports on artificial incorporation of drugs into hair, very little detail is included in regard to processes, and none have investigated varying effects to incubation time and temperature. This study demonstrated that artificial incorporation is possible, and the level of incorporation can be altered through variation of temperature and solvent ratios. Results show that higher temperatures result in better incorporation for most drugs studied. The methanol/DMSO ratio was also shown to influence the level of incorporation, with increased incorporation observed when the methanol/DMSO ratio was higher. Preliminary work into the use of TOF-SIMS for cross sectional analysis of the hair was unsuccessful. Thus, it was not possible in this study to determine how accurately the artificially incorporated hairs represented authentic hairs, and additional work is needed. Regardless, this work present new insights on how effectively drugs can be incorporated into hair.

Keywords: hair analysis, microwave-assisted extraction, ionic liquid composite, Olaplex

Subject: Forensic & Analytical Chemistry thesis

Thesis type: Doctor of Philosophy
Completed: 2018
School: College of Science and Engineering
Supervisor: Paul Kirkbride