Abstract
Allisartan isoproxil (ALS-3) is a selective, nonpeptide blocker of the angiotensin II type 1 receptor. It is a new antihypertensive drug under development with a novel chemical structure. The aim of this study was to evaluate the potential toxicity of ALS-3 in Sprague-Dawley rats. Animals were orally administered either vehicle or ALS-3 at doses of 20, 80 and 320 mg/kg once-daily for 26 weeks, followed by a 6-week recovery period. Toxicity was assessed by mortality, clinical signs, body weight, food consumption, hematology, coagulation, serum chemistry, gross necropsy, organ weights and microscopic examination. Decreased body-weight gain was noted at 320 mg/kg/day in both sexes as well as at the 80-mg/kg/day dose in females. Food consumption was decreased at all doses in males and at 80- and 320-mg/kg/day doses in females. Decreased erythrocyte parameters (erythrocyte count, hemoglobin and hematocrit) were observed in males receiving 320 mg/kg/day. Elevated urea nitrogen (BUN), increased kidney weight, decreased heart weight and exacerbation of chronic progressive nephropathy (CPN) severity were all observed in males at 80 and 320 mg/kg/day. However, only an exacerbated incidence of CPN was observed in females at 320 mg/kg/day. All changes were reversed after the 6-week recovery period, except BUN and CPN. Based on these results, we concluded that a dose of 20 mg/kg/day was the no observed adverse effect level. The toxicity target organ was the kidney. Males were more affected than females.
Acknowledgements
The authors are grateful to Dr. J.H. Sun for critical reading of the manuscript. The authors would also like to acknowledge all colleagues who participated in this study.