Evaluation of the genotoxic potential of zinc pyrithione in the Salmonella mutagenicity (Ames) assay, CHO/HGPRT gene mutation assay and mouse micronucleus assay.

The mutagenic potential of zinc pyrithione (Znpt) was evaluated in vitro in the Salmonella/mammalian microsome plate incorporation mutagenicity (Ames) assay and the CHO/HGPRT gene mutation assay. The clastogenic potential of Znpt was evaluated in vivo using the mouse micronucleus test. Znpt was negative in the Ames test in five tester strains in the presence and absence of rat liver microsomal enzymes when assayed at concentrations ranging between 10 and 333 micrograms per plate and between 0.03 and 33 micrograms per plate, respectively. Znpt also produced negative results in the CHO/HGPRT assay. No significant increases in mutant frequencies were seen in the presence and absence of rat liver microsomal enzymes. In each case, the highest concentrations reduced cellular viability by 83% and 85%, respectively. Znpt also did not induce increased frequencies of micronuclei in mouse bone marrow cells when tested at the maximally tolerated dose (MTD) (44 mg kg-1). These data support the conclusion that Znpt lacks genotoxic activity under the conditions of these tests.