THE EVALUATION OF PESTICIDE INGREDIENTS AND FORMULATIONS IN-VITRO ANDCORRELATIONS WITH IN-VIVO DATA

Pesticides are often insoluble directly in aqueous solvents, but can b e dissolved/suspended in surfactant-based formulations. Both surfactan ts and pesticides can induce irritation. Since a single in vitro assay has proved inadequate for evaluating the toxicity of a chemical and i ts ability to cause an irritant response, a combination of assays was employed to examine the potential toxicities of two pesticide formulat ions. The surfactant-based vehicles had toxicities that reflected thei r surfactant concentration. The formulation containing 5% permethrin r equired a more concentrated vehicle than was needed to dissolve 0.1% c ypermethrin. In vitro, the ID50 dose (i.e. the dose which inhibited th e increase in total cellular protein by 50%) was 576 mu g/ml for the p ermethrin formulation and 1080 mu g/ml for the cypermethrin formulatio n. This corresponded closely to the ID50 values for the vehicles alone (464 mu g/ml and 1230 mu g/ml, respectively). When tested at high con centrations on confluent cells over a 1-minute exposure period to mimi c potential exposure of the eye, the more concentrated vehicle, Lanoso l 50 ME, was 4-6 times more toxic than Siege II. Technical grade perme thrin and cypermethrin had low toxicities in each of the in vitro test s employed. Taken together, these results reflected the in vivo profil es available.