1981 年 101 巻 6 号 p. 556-566
The concentrations of o-ethoxybenzamide (EBA), N-(β-hydroxybutyryl)-p-phenetidine (HBP) and metabolites in the rabbit serum were investigated when EBA was administered orally with HBP and EBA or HBP administered alone. 1) The concentration of EBA in the serum increased when 100 mg/kg of EBA was administered concurrently with 28.5, 33.3 and 62.5 mg/kg of HBP as compared with the administration of 100 mg/kg of EBA alone. The co-administration of EBA and HBP also decreased the concentration of salicylamide (SAM) sulfate in the serum. 2) The concentration of HBP in the serum increased when 28.5, 33.3 and 62.5 mg/kg of HBP and 100 mg/kg of EBA were administered together, while that of N-(β-hydroxybutyryl)-p-aminophenol (HBA) glucuronide was decreased. 3) The deethylation of EBA was inhibited competitively by the addition of HBP, and also the deethylation of HBP inhibited competitively by the addition of EBA in 9000×g supernatant fraction of the rabbit liver. 4) The area under the serum concentration-time curve (AUC, 0-8 hr) of SAM sulfate approached a limiting value when 300 mg/kg of EBA was administered orally, while the AUC values of SAM glucuronide, EBA, SAM total and SAM total plus EBA increased with increasing doses of EBA. 5) The deethylation of HBP approached a limiting value when 300 mg/kg of HBP was administered orally, while the AUC values of HBP and HBA total plus HBP total (HBP plus HBP glucuronide) increased with increasing doses of HBP.