Final Report of the Cosmetic Ingredient Review Expert Panel Safety Assessment of Coal Tar

Coal Tar is a semisolid byproduct obtained in the destructive distillation of bituminous coal which functions in cosmetic products as a cosmetic biocide and denaturant — antidandruff agent is also listed as a function, but this is considered an over-the-counter (OTC) drug use. Coal Tar is a nearly black, viscous liquid, heavier than water, with a naphthalene-like odor and a sharp burning taste, produced in coking ovens as a byproduct in the manufacture of coke. Crude Coal Tar is composed of 48% hydrocarbons, 42% carbon, and 10% water. In 2002, Coal Tar was reported to FDA to be used in four formulations, all of which appear to be OT C drug products. Coal Tar is monographed by the Food and Drug Administration as Category I (safe and effective) for over-the-counter drug ingredient for use in the treatment of dandruff, seborrhoea, and psoriasis. Coal Tar is absorbed through through the skin of animals and humans and is systemically distributed. In short term studies, mice fed Coal Tar in their diet found their diet unpalatable, but no adverse effects were reported other than weight loss; rats injected with Coal Tar experienced malaise in one study and decreased water intake and increased liver weights in another; rabbits injected with Coal Tar residue experienced eating avoidance, respiratory difficulty, sneezing, and weight loss. In a subchronic neuro toxicity study using mice, a mixture of phenols, cresols, and xylenols at concentrations approximately equal to those expected in Coal Tar extracts produced regionally selective effects, with a rank order of striatum > cerebellum > cerebral cortex. Coal Tar applied to the backs of guinea pigs increases ep idermal thickness. Painting female rabbits with tar decreases the absolute and relative weights of the ovaries and decreased the number of interstitial cells in the ovary. Four therapeutic Coal Tar preparations used in the treatment of psoriasis screened using the Ames test were mutagenic. Urine and blood from patients treated with Coal Tar were geno toxic in bacterial assays. Coal Tar was genotoxic in a mammalian genotoxicity assay and induced DNA adducts in various tissue types. Chronic exposure of mice significantly decreased survival and liver neoplasms were seen in a significant dose-related trend; in other studies using mice lung tumors and perianal skin cancers were found. Coal Tar was comedogenic in three small clinical studies. Folliculitis is associated with the prolonged use of some tars. Several published reports describe cases of contact sensitivity to Coal Tar. Po lycyclic aromatic hydrocarbons which make up Coal Tar are photosensitizers and cause phototoxicity by an oxygen dependent mechanism. A retrospective study of the reproductive toxicity of Coal Tar in humans compared exposed women to controls and found little difference in spontaneous abortion and congenital disorders. Cancer epidemiology studies of patients who have received Coal Tar therapy of one form or other have failed to link treatment with an increase in the risk of cancer. While the CIR Expert Panel believes that Coal Tar use as an antidandruff ingredient in OTC drug preparations is adequately addressed by the FDA regulations, the Panel also believes that the appropriate concentration of use of Coal Tar in cosmetic formulations should be that level that does not have a biological effect. Additional data needed to make a safety assessment include product types in which Coal Tar is used (other than as an OT C drug ingredient), use concentrations, and the maximum concentration that does not induce a biological effect.