Acute toxicity of lefucoxib in rats, mice and Beagles

Objective To observe the toxic reaction in animals after a single drug was given and to calculate the LD50 or the maximum dose.Methods NIH mice were given lefucoxib by gavage at the dose of 5.0g/kg,once a week for 10 weeks,and the largest volume was 0.8mL.Acute toxicity in rats was detected after a single fixed-dose of oral lefucoxib(2 000mg/kg).Beagles received an approximate lethal dose of lefucoxib in accordance the Guiding Principles of Chemical and Therapeutic Biological Products.Results No statistical change was found in body weight between NIH mice and controls one week after treatment.The maximum tolerable dose was over 5.0g/kg.No statistical difference was observed in the food intake and body weight of rats between treatment and control groups.The appetite,activity and body temperature of beagles were normal with no obvious change in heart rate and electrocardiogram.No congestion,bleeding and infection occurred in the heart,liver,kidney,lung,spleen and digestive tract of beagles.Conclusion Lefucoxib has low toxicity and the approximate lethal dose cannot be determined in beagles.The highest non-lethal dose is over 5.0g/kg.