Abstract: 【ABSTRACT】 BACKGROUND ＆ AIM： To investigate whether two highly effective photoinitiators, Bis(p-toly)iodonium hexaflurophosphaye(IHT-PI 820)and 2-Isopropylthioxanthone(IHT-PI ITX)are mutagenic. MATERIAL AND METHODS： The bacterial reverse mutation assay was used with S.typhimurium TA98, TA100, TA1535, TA1537 and E.coli WP2 uvrA. The plate incorporation method was performed with and without metabolic activation. RESULTS： In the absence of metabolic activation ,IHT-PI 820 induced the number of revertant colonies of five tester strains,and IHT-PI ITX induced the number of revertant colonies of TA98 all in a dose-dependent manner.In the presence of metabolic activation,IHT-PI 820 induced the number of revertant colonies of TA98, TA1537 and WP2 uvrA, all in a dose-dependent manner. CONCLUSION: Both IHT-PI 820 and IHT-PI ITX induced point mutations in the tester strains.These two highly effective photoinitiators may have potential genotoxicity for human bodies.

Key words: Bis(p-toly)iodonium hexaflurophosphaye(IHT-PI 820), 2-Isopropylthioxanthone(IHT-PI ITX), bacterial reverse mutation assay, mutagenicity, heritabletoxicity