twenty-eight-day-old sprague-dawley rats were fed amoxicillin ( 50 mg/kg/dose ) , ampicillin ( 50 mg/kg/dose ) , cefaclor ( 50 mg/kg/dose ) , cephalexin ( 50 mg/kg/dose ) , erythromycin ( 50 mg/kg/dose ) , penicillin v ( 50 mg/kg/dose ) or sulfamethoxazole ( 20 mg/kg/dose ) and sera were assayed for antibiotics at 1 , 2 , 4 , 6 and 12 hours after therapy .
C0007537
cefaclor
C0007716
cephalexin