Acute, pharmacokinetic, and subchronic toxicological studies of 2,4-dichlorphenoxyacetic acid

• Published in: Fundamental and applied toxicology 1987-01, Vol.9 (3), p.423-435
• Main Authors: Gorzinski, S J, Kociba, R J, Campbell, R A, Smith, F A, Nolan, R J, Eisenbrandt, D L
• Format: Article
• Language: English
• ISSN: 0272-0590

The single-dose oral LD sub(50) values in Fischer 344 rats for technical-grade 2,4-dichlorophenoxyacetic acid (2,4-D), esters, and salts ranged from 553 mg/kg (isobutyl ester in females) to 1090 mg/kg (dimethylamine salt in males). The LD sub(50) values for the acid, esters, or salts, when expressed as acid equivalents, were consistent which suggests that the acute toxicity was due to 2,4-D per se. Acute dermal LD sub(50) values in rabbits for the acid, esters, and salts were greater than 2000 mg/kg. Overall, these results indicate that the acute oral and dermal toxicity of 2,4-D are low. The amount of 2,4-D in the plasma, kidney, and urine 6 hr postdosing indicated that the urinary elimination of 2,4-D was saturated in male rats given oral doses in excess of 50 mg/kg. Subchronic dietary studies in male and female Fischer 344 rats used dose levels of 0, 15, 60, 100, or 150 mg/kg/day of purified or technical-grade 2,4-D acid for 13 weeks. Body weight gains were decreased for both sexes at the higher dose levels of purified and technical-grade 2,4-D acid.