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 vit ro in the Salmonella/mammalian microsome plate incorporation mutagenic ity (Ames) assay and the CHO/HGPRT gene mutation assay. The clastogeni c potential of Znpt was evaluated in vivo using the.mouse micronucleus test. Znpt was negative in the Ames test in five tester strains in th e presence and absence of rat liver microsomal enzymes when assayed at concentrations ranging between 10 and 333 mug per plate and between 0 .03 and 33 mug per plate, respectively. Znpt also produced negative re sults in the CHO/HGPRT assay. No significant increases in mutant frequ encies were seen in the presence and absence of rat liver microsomal e nzymes. In each case, the highest concentrations reduced cellular viab ility 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 These data support the co nclusion that Znpt lacks genotoxic activity under the conditions of th ese tests.