Adult Volunteers

Five volunteers received intramuscular injections of 7 mg (approximately 500 mg) of cephanone, a new cephalosporin for parenteral use per kg. Peak serum concentrations averaged 36 jig/ml, about four times as high as with the same doses of cephalothin, twice as high as with cephaloridine, and slightly lower than with cefazolin. With a constant intravenous infusion of 100 mg/h, a steady-state serum concentration of 31 tsg/ml was attained in four volunteers. The serum half-life was similar for the intramuscular and intravenous studies, 2.4 and 2.6 h, respectively. Over 90% of the dose administered was recovered in the urine. The factor mainly responsible for the higher and more sustained serum concentrations of cephanone was its low renal clearance of 47 ml per min per 1.73 m2. Cephanone has a small apparent volume of distribution, probably related to its high serum protein binding of 88%.