[General pharmacology of T-3262, a new pyridonecarboxylic acid]

General pharmacological activities of (+/-)-7-(3-amino-1-pyrrolidinyl)-6-fluoro-1-(2,4-difluorophenyl)-1,4- dih ydro- 4-oxo-1,8-naphthyridine-3-carboxylic acid p-toluenesulfonate hydrate (T-3262), which is a new pyridonecarboxylic acid, were examined with the following results. 1. Central nervous system: T-3262 did not show any significant pharmacological effects at oral doses of 100-1,000 mg/kg but caused slow waves in spontaneous EEG in cats at intravenous doses of 10-30 mg/kg. 2. Respiratory and cardiovascular system: T-3262 produced little effect in normotensive rats and anesthetized rabbits at oral doses of 100-1,000 mg/kg and intravenous doses of 3-30 mg/kg, respectively. But T-3262 caused, dose-dependently, an increase of respiratory rate, hypotension, decrease of heart rate and changes in ECG patterns (elevation of T waves, slow amplitudes of QRS complexes and prolongation of RR interval, etc.) in anesthetized dogs at intravenous doses of 3-10 mg/kg. 3. Renal functions: T-3262 increased electrolyte excretions at oral doses of 300-1,000 mg/kg but did not affect PSP excretion in rats. 4. Autonomic nervous system and smooth muscle organs: T-3262 exerted slight inhibition of gastric output in rats and slight miosis in mice at an oral dose of 1,000 mg/kg. But T-3262 did not affect the contraction of nictitating membrane in anesthetized cats at intravenous doses of 1-30 mg/kg. T-3262 increased spontaneous motilities of isolated stomach, ileum and uterus, but decreased that of isolated colon at concentrations of 10(-5)-10(-4) g/ml. 5. Hematological examinations: T-3262 did not show any significant effects on bleeding time, blood coagulation, platelet aggregation and blood glucose level in rats at oral doses of 100-1,000 mg/kg. 6. Miscellaneous effects: T-3262 exerted slight inhibitions of gastric secretion and of carrageenin-induced hind paw edema in rats at a dose of 1,000 mg/kg administered intraduodenally and orally, respectively. T-3262 did not affect neuromuscular junction and bile secretion in rats at intravenous doses of 3-30 mg/kg and oral doses of 100-1,000 mg/kg, respectively. From these results, it can be assumed that T-3262 has a wide safety margin as an oral antibacterial agent.