BIOCHEMICAL APPROACH ON THE CONSERVATION OF DRUG MOLECULES DURING HAIR FIBER FORMATION

A biochemical concept for the endogenous incorporation of drug molecul es into growing hair is presented. It is based on the principles of tr ansport across biomembranes, on the principles of biotransformation an d drug melanin affinity. The approach gives explanations for current o bservations in hair analysis, which up to date have not been understoo d sufficiently. Phenomena such as the ratio of parent drug to metaboli te in hair, the dependence of incorporation on the physico-chemical pr operties of the drug, the independence of drug incorporation on active melanogenesis (incorporation into non-pigmented hair) as well as the dependence of drug content on hair pigmentation are elucidated. (C) 19 97 Elsevier Science ireland Ltd.