Cocaine and metabolites in human graying hair: Pigmentary relationship

Objective: To assess differences in the binding of cocaine, cocaethylene, and benzoylecgonine among pigmented and senile white hairs of the graying human cocaine abuser. Design A sheath of graying hair in the region around the apex of the head was gathered between the thumb and index finger then cut and removed about 2 mm proximal to the scalp. The graying hair was divided into pigmented and senile white of equal weights and lengths and then analyzed by gas chromatography/mass spectrometry chemical ionization. Twenty-nine such pairs were analyzed. Subjects: Male cocaine abusers, ages 33-55 years hospitalized for substance abuse. Informed consent was obtained and confidentiality assured. Main Outcome Measures: Concentrations of cocaine, cocaethylene and benzoylecgonine in ng were assessed for each of 29 paired hair samples by gas chromatography/mass spectrometry chemical ionization. Results: There were statistically significant differences between pigmented and senile white sections of paired samples. Cocaine (ng/mg hair, mean +/- SD) was 31.5 +/- 30.2 for pigmented hair vs 14.9 +/- 19.8 for senile white portions; (p < 0.0001). Cocaethylene (ng/mg hair, mean +/- SD) 3.22 +/- 5.0 (pigmented) vs 0.52 +/- 0.88 (senile white); (p < 0.0016). Benzoylecgonine (ng/mg hair, mean +/- SD) 5.1 +/- 5.3 (pigmented) vs 3.9 +/- 4.8 (senile white), (p < 0.005). Conclusion: Melaninated pigmented hair seems to bind more cocaine, cocaethylene and benzoylecgonine than white hair in the same subject.