Assessment and detection: The effect of hair pigment on the incorporation of fatty acid ethyl esters (FAEE)

Aims: The objective of the current study was to determine whether FAEE incorporation is affected by hair pigmentation. Methods: Black hooded LE rats were injected intraperitoneally daily with ethanol. Prior to dosing, black and white patches of fur were shaved and analyzed for baseline levels of FAEE using an adapted extraction procedure and GCMS method. Once the shaved 'patches' had grown back they were re-sampled along with hair outside the 'patches', referred to as 'no patch' hair, and tested for post-treatment FAEE levels in the same manner. Blood was also sampled for pharmacokinetic analysis of ethanol. Results: Total FAEE levels were significantly higher in post-treatment hair (black and white) compared to baseline (pre-treatment) levels. Total FAEE levels were also significantly higher in post-treatment 'patch' hair (black and white) compared to 'no patch' hair. No significant differences were found between post-treatment black and white hair. The FAEE profiles were similar between black and white hair, with FAEE levels being highest for ethyl myristate, followed by ethyl stearate, palmitate, and then oleate. Conclusion: FAEE incorporation into hair does not appear to be affected by hair pigment, which is in congruence with what is known about the chemistry of drug-melanin interactions. This is important in avoiding potential bias and discrimination in the interpretation of alcohol abuse based on hair color.