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USDTL Research

The Stability of Drugs in Hair

The Stability of Drugs in Hair After Treatment With Two Varieties of Chemical Straighteners (Those Containing Lye And Those Not Containing Lye)
By: Dr. Jeanita S. Pritchett

Hair testing is gaining popularity as a specimen of choice when it comes to testing for drugs of abuse. It is important, therefore, to study its limitations as well as its advantages. While attending the 2012 SoHT conference, we listened to a very important presentation on the influence of chemical straightening on the stability of drugs of abuse in hair samples treated by two different kinds of relaxers/straighteners by Dr. Jeanita Pritchett. She agreed to an interview to introduce her study and her findings to our readers.

[USDTL]: Dr. Pritchett, could you please give our readers a little bit about your background and work you have done.

[JSP]: I graduated with a B.S. in Professional Chemistry from Tennessee State University in 2005, and then followed up with a Ph.D. in Analytical Chemistry in 2011 from the University of Illinois at Chicago. After completion of my degree, I was awarded a National Research Council Postdoctoral Fellowship at the National Institute of Standards and Technology (NIST) in Gaithersburg MD. Since beginning at NIST, I have had the opportunity to participate in a multitude of forensic and toxicology related research projects.

[USDTL]: What made you question the role hair relaxers may play in screening substances of abuse in hair samples?

[JSP]: While perusing articles concerning the effects of cosmetic treatments on the stability of illicit drugs found in hair, I realized that I had not come across any that focused on what occurs after application of a chemical straightener (also known as a Relaxer) to hair. I found an abundance of articles that examined the effects of common treatments such as shampooing, dyeing, and alkaline waving (Perm). We hypothesized that there would be a high degree of change in the measured concentration of illicit drugs post application of relaxers. Fortunately, at NIST we have two Standard Reference Materials (SRMs) with certified values for the drugs of interest in this study (cocaine and its major metabolites benzoylecgonine and cocaethylene, phencyclidine, and Δ-9 tetrahydrocannibinol) which we could use to test this theory in a more controlled environment.

[USDTL]: Did you see a significant trend in your results?

[JSP]: Yes we did. In fact, only 6-67% of the original concentration remained after a single chemical straightening treatment with the greatest effect being on cocaine. Since the SRMs consist of drug fortified hairs, we also tested hairs clipped from authentic cocaine users who had ingested the drug. After the specimens from an authentic user were treated for 15 minutes with both types of relaxer (Lye and No-Lye), only 5-30% of Benzoylecgonine (BZE), Cocaine (COC), and Cocaethylene (CE) remained when compared to a sample of the same user that was not treated with either type of relaxer (Control).

[USDTL]: Were you surprised by your results? Why or why not?

[JSP]: Considering the harsh conditions (high pH 12-14) that the hair is being exposed to and the fact that the cuticle is being lifted as well as disulfide bonds being broken, I wasn’t surprised by the results. A similar attenuation was seen by others after shampooing, dyeing, and alkaline waving.

[USDTL]:What is your study’s main message take-away for our readers?

[JSP]: Results of this study have demonstrated that it would be possible for a drug abuser to intentionally apply a relaxer to yield drug concentrations approaching or below the established National Institute on Drug Abuse/Society of Hair Testing cut-off levels. Because of this, the analyst should inquire about a subject’s cosmetic treatment history prior to analysis to ensure accurate results are obtained.

[USDTL]: Thank you Dr. Pritchett for your insight and for sharing your study with our readers.

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