Evaluation of dermal irritancy potential of benzanthrone-derived dye analogs: structure activity relationship

The twelve structural analogs of benzanthrone-derived dyes of commercial use were screened for their dermal irritation potential response using the Draize occlusive patch test. The test dyes, dissolved in DMSO as vehicle, were topically applied on the skin of the male Druckery rats (160 +/- 10 g) according to the OECD protocol. The potential dermal hazard was assessed in terms of the primary cutaneous irritation (PCI) index and irritancy. Irritancy was evaluated according to the AFNOR scale. In terms of irritancy, the twelve benzanthrone dyes qualified as moderately irritant (3.0-5.0) according to the above scale. In decreasing order, PCI index of the various dyes was: Navy Blue R (4.5); Jade Green XBN (4.25); 16, 17-dihydroxydibenzanthrone (3.84); Black NB (3.75), Jade Green 2G (3. 75); 3-bromobenzanthrone (3.58); Brilliant Purple 4R (3.58); Olive D (3.50); Dark Blue 2R (3.41); Olive Green B (3.33); isodibenzanthrone (3.33), and benzanthrone (3.16). These results indicate that benzanthrone-derived dyes/dye intermediates caused dermal toxicity which appears to be influenced by the number of carbonyl and amino-anthraquinone groups as well as by the presence of functional groups like halogen, nitro, hydroxy and methoxy in the parent molecule, benzanthrone.