A contribution to a new test method for dandruff-inhibiting and "keratolytic" action of drugs.

Free cholesterol in lipids from the scalp and hair is predominantly a constituent of epidermal lipids. Therefore, a reduction in cholesterol content induced by a drug indicates a reduction in cell turnover in the epidermis. As, according to the literature, increased cell turnover in the epidermis results in formation of dandruff, a reduction in the proportion of cholesterol should indicate inhibition of the formation of dandruff. Conversely, an increase in free cholesterol should generally indicate a "keratolytic" effect. So unequivocal an interpretation has not so far been possible in persons with dandruff, as it was not known whether free cholesterol was increased or decreased. In addition, this interpretation was not possible after use of antimicrobial substances, as in vitro investigations had failed to exclude microbial esterification of cholesterol on the scalp. The present investigation has shown that correlation of free cholesterol level with cell turnover is permissible in patients with dandruff, even if antimicrobial drugs are being tested.