Vol.55 No.S-1 October 2007
Three-month repeated oral dose toxicity study of garenoxacin in cynomolgus monkeys
1)Research Laboratories, Toyama Chemical Co., Ltd., 2-4-1 Shimookui, Toyama, Japan
2)Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd.
Abstract
Garenoxacin(mesilate hydrate, GRNX) was administered by oral gavage to male and female cynomolgus monkeys at doses of 10, 30, and 100 mg/kg once daily for 3 months and toxicity assessed. Reversibility of toxic changes was also assessed in animals receiving 30 and 100 mg/kg following 3-month withdrawal. Animals receiving 100 mg/kg showed vomiting and salivation during the dosing period; these clinical signs were seen approximately just after dosing and disappeared with time. In histopathology, stomachs of animals receiving 100 mg/kg showed atrophy of fundic glands at the termination of the dosing period; this change improved by withdrawal. Abnormalities attributable to GRNX at each dose were not observed in body weight changes, food consumption, ophthalmology, electrocardiography, auditory sense, urinalysis, hematology, or blood chemistry. In the present study, no observed adverse effect level was established at 30 mg/kg, and systemic exposure of GRNX at this dose level was as follows: Cmax was 11.2-16.9 μg/mL, and AUC was 88.6-159 μg·h/mL. Reddish-purple discoloration of several organs and tissues including oral mucosa, and blackish brown discoloration of thyroids were observed in animals receiving 30 mg/kg and above. However, organs and tissues with discoloration did not have histological abnormalities related to the gross finding, and serum levels of thyroid hormones(triiodothyronine (T3), thyroxine (T4), free T3, and free T4) were not affected. Reversibility of discoloration was shown by withdrawal.
Key word
garenoxacin, des-fluoro(6)-quinolone, monkey, subacute toxicity
Received
May 9, 2007
Accepted
July 6, 2007
Jpn. J. Chemother. 55 (S-1): 42-53, 2007
