5 Final Report on the Safety Assessment of 2-Nitro-p-Phenylenediamine and 4-Nitro-o-Phenylenediamine

Abstract

Animal data on 2NPPD and 4NOPD and cosmetic hair dyes containing these ingredients suggest that both compounds were nonirritating to rabbit skin and eyes, but were sensitizers on guinea pig skin. The results of repeated insult patch tests with hair dye products containing these ingredients indicated that neither was an irritant or a sensitizer to human subjects as normally used. In the absence of human data on the pure compounds, however, 2NPPD and 4NOPD are considered to be potential human sensitizers. Topically applied 2NPPD and 4NOPD are absorbed by experimental animals. Neither embryotoxicity nor teratogenicity was observed in animal studies when hair dyes containing 2NPPD and 4NOPD were applied to the skin. Both ingredients were mutagenic in some bacterial and in vitro mammalian systems; both compounds had some genotoxic activity. In feeding studies in mice and rats, only 2NPPD induced hepatocellular tumors in female mice. Both compounds were noncarcinogenic in male mice and in rats of either sex. Epidemiological data have not demonstrated a carcinogenic effect in man for hair dyes. For those persons not sensitized, it is concluded that 2NPPD and 4NOPD are safe as hair dye ingredients at the current concentration of use.