COMPARISON OF THE UP-AND-DOWN, CONVENTIONAL LD(50), AND FIXED-DOSE ACUTE TOXICITY PROCEDURES

The up-and-down procedure (UDP), fixed-dose procedure (FDP) and conven tional LD(50) tests were compared to determine their consistency in ch emical hazard classification for acute oral toxicity according to the European Economic Community (EEC) system. There was consistent classif ication for 23 out of 25 cases between the UDP and the conventional LD (50) results, in 16 out of 20 cases between the FDP and the convention al LD(50), and in seven out of 10 cases between the UDP and the FDP. T he UDP needed only between six and 10 animals of one sex (fewer than e ither the LD(50) or the FDP). Available literature indicates that the sexes are usually similar in their acute toxicity responses and that o f females are often more sensitive than males when acute toxicity diff erences do exist, thus obviating the need for both sexes to be tested in most cases. Unlike the FDP, the UDP also estimates an LD(50), thus providing data directly applicable to all current hazard classificatio n systems based on acute oral toxicity.