Phototoxicity of bituminous tars-correspondence between results of 3T3 NRU PT, 3D skin model and experimental human data.
Bituminous tars (Ichthammol and Ichthyol Pale) are widely used in pharmaceutical, veterinary and cosmetic industries for their anti-microbial, anti-inflammatory and anti-pruritic effects. In contrast to coal tar, no phototoxicity of bituminous tars has been reported in man, although both Ichthammol and Ichthyol Pale exhibit UV absorption which is higher and broader for the former. The validated 3T3 NRU phototoxicity test indicated phototoxic potential of both substances. The phototoxicity test in a 3D human skin model (EpiDerm) only confirmed phototoxicity for Ichthammol. Human data on Ichthammol phototoxicity are missing. A photopatch test in human volunteers was performed in order to clarify the discrepancy between the phototoxicity found in the skin model and the absence of reported human phototoxicity. Following 4h exposure to 5% and 10% aqueous solutions of Ichthammol and Ichthyol Pale the test sites were irradiated with a UVA dose of 5 J/cm(2). Early phototoxic reaction (erythema) within 4-6h after irradiation was only elicited by Ichthammol and not by Ichthyol Pale. These data correspond well with those from the 3D skin model test and suggest the necessity to employ several test systems for final phototoxicity assessment. In addition to the results obtained in 3T3 NRU PT, further testing on 3D skin models may better reflect bioavailability of a given chemical in the skin, relevant to the situation in humans.
Jirová
D
D
National Reference Center for Cosmetics, National Institute of Public Health, Srobárova 48, 100 42 Prague 10, Czech Republic. djirova@iol.cz
Kejlová
K
K
Bendová
H
H
Ditrichová
D
D
Mezulániková
M
M
D000328:Adult; D000368:Aged; D000826:Animal Testing Alternatives; D000818:Animals; D041702:BALB 3T3 Cells; D002470:Cell Survival / Q000187:drug effects; D017484:Dermatitis, Phototoxic / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D051379:Mice; D008875:Middle Aged; D009924:Organ Culture Techniques; D010328:Patch Tests; D000644:Quaternary Ammonium Compounds / Q000008:administration & dosage / Q000633:toxicity*; D012867:Skin / Q000187:drug effects* / Q000473:pathology; D013638:Tars / Q000633:toxicity*; D014466:Ultraviolet Rays
D000644:Quaternary Ammonium Compounds; D013638:Tars; C089399:ichthammol