A review of available sources identified mouse and rat LD50 for oral and intraperitoneal routes. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The rat oral LD50 was the most preferred species and route; it was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
· TEEL-1 = TEEL-2/11
· TEEL-2 = TEEL-3/6
· TEEL-3 = Rat oral LD50 (3073 mg/kg)
This review generated TEEL values that are significantly less conservative than those Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse intraperitoneal LD50. The current TEEL-3 basis is a rat oral LD¬¬50, but a more preferred species and route than Rev. 29A. The methodology to derive TEEL-2 and TEEL-1 values remains unchanged (Table 3.5).