ABSTRACT
The incorporation of drugs into hair was primarily ascribed to the transportation by passive diffusion of the substances present in blood into the growing cells located at the base of the follicle of the hair where the drugs, as the cells die and fuse to form hair strands, become trapped and tightly bound in the keratin matrices during subsequent keratogenesis. According to this model, drug incorporation into hair is dependent on the drug concentration in blood which, in turn, is dependent on the dose of drug ingested.
