A review of available sources identified animal (dog, guinea pig, mouse, rabbit) and human acute toxicity data (LDLo, LD50) for various routes (oral, intravenous, subcutaneous). 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 3.6.2, 3.6.3, 3.6.4, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The human (male) LDLo was evaluated for TEEL development. Although the man died after orally consuming an unknown dose of brucine, an autopsy determined that the concentration of brucine in his femoral blood was 1.51 µg/mL. Femoral blood is widely accepted as the most reliable postmortem specimen for drug analysis in forensic toxicology and measurement of the lethal concentration of femoral blood is comparable to an intravenous dose; therefore, the analysts used this dose as equivalent to an intravenous LDLo (1.51 µg/mL). Using a blood density of 1 g/mL, analysts converted this dose to 1.51 mg/kg. This human (male) LDLo (1.51 mg/kg) 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 = Human (male) intravenous LDLo (1.51 µg/mL)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat intraperitoneal LD50 (91 mg/kg) that was identified during this review, but not selected due to the unavailability of human acute toxicity data. The Rev. 29A TEEL-2 basis was a rat intraperitoneal TDLo not found during the review. The Rev. 29A and current TEEL-1 used the same methodology (Table 3.5), with differences due to the change in TEEL-2.