Sixty-day repeated dose toxicity of sinafloxacin in rats and dogs

Sinafloxacin is a new quinolone antibacterial agent. The present study was conducted to determine its toxicity at low flow rate intravenous infusion doses of 0, 10, 30, and 60 mg/kg/day in rats and at 0, 25, 50, and 100 mg/kg/day in dogs 6 days per week for 60 days. A 20-day recovery period was included at the end of the study to evaluate the reversibility of the toxic effects. During the treatment and recovery periods, the effects of the test agent on mortality, body weight, food consumption, hematology, serum biochemistry, urinalysis, electrocardiogram (ECG), organ weights, bone marrow, and histopathology were examined. There were no treatment-related mortalities. Dysphoria and local irritation were observed in rats during administration, but the rats recovered soon after administration. Dysphoria, dermal rubeosis, salivation, vomiting and local irritation were observed in dogs receiving 50 or 100 mg/kg/day during administration, but all dogs also recovered within 30 min after infusion. Significant increases in total bilirubin and glucose, and a significant decrease in total protein were observed in rats receiving the 60 mg/kg/day dose at the end of treatment period, but the levels returned toward normal during the 20-day recovery period. The most apparent toxicity was the digestive system of both rats and dogs, with irritation also occurring in the vein used for infusion. There were also notable effects on the endocrine system in rats and the central nervous system (CNS) in dogs. However, these toxic effects of sinafloxacin were transient and were reversible. The no-observed adverse effect level (NOAEL) in rats and dogs was 30 mg/kg/day and 25 mg/kg/day, respectively.