Incorporation in liposomes as a method for the application of genotoxins of low water solubility in the SCE assay.

Benzo[alpha]pyrene BaP), freely dissolved or incorporated in liposomes prepared from egg yolk lecithin, was checked for SCE induction in Chinese hamster V79-E and rat liver RL-19 cells in vitro. SCE induction in V79-E was observed only when freely dissolved BaP was added together with S9 mix. RL-19 cells were per se highly sensitive to SCE induction by BaP either freely dissolved or incorporated in liposomes. It is suggested that the incorporation of genotoxins in liposomes is a practicable method for the application, in mammalian genotoxicity assays, of agents which are barely soluble or completely insoluble in water, provided no exogenous metabolizing system is required.