Apparent Signs Of Toxicity Research Articles

Long-term toxicity study of mycophenolic acid in rabbits

Rabbits were chosen for a long-term toxicity study of mycophenolic acid (MPA) because the rate of formation of the MPA-glucuronide metabolite was rapid and similar to that for man and because they were able to tolerate larger daily doses than other laboratory species such as rats, dogs, and monkeys. Dutch Belted rabbits were given daily (5 days/week) oral doses of 0, 80, or 320 mg of MPA/kg for 1 yr. Survival of the animals was similar for each test group. There were no apparent signs of toxicity. The hematologic and blood chemistry values were unaffected with the exception of a dose-related decrease in lactic dehydrogenase (LDH). It was concluded that the rabbit was an appropriate animal model and tolerated large daily doses of MPA for 1 yr without important treatment-related changes.

Some Pharmacological Characteristics of Bacitracin II. Absorption and Excretion of Bacitracin in the Dog.

SummaryThe absorption and excretion of bacitracin have been studied in the dog. Only small fractions of the oral dose were recovered in the stool. Since none was found in the blood or urine after oral administration and little was found in the feces, it appears that the antibiotic was largely destroyed in the gastro-intestinal tract. Following parenteral administration of large single doses, significant concentrations of the drug persisted in the blood stream for as long as 7 or 8 hours. Other than slight and transient central effects produced by excessively rapid intravenous injection, the animals showed no apparent signs of toxicity in spite of the fact that doses as high as 6,000 units per kg body weight were administered. The recovery of the drug in the urine appeared, in general, to increase in direct ratio to the dose administered, but the recoveries were widely variable. Significant concentrations of bacitracin persisted in the urine for more than 7 hours after administration of a single dose of th...