[Comparative pharmacokinetics of oral cephalosporins: cephalexin, cefaclor and cefadroxil (author's transl)].

In a randomized crossover study, the pharmacokinetics of two new cephalosporin antibiotics, cefaclor (CCL), and cefadroxil (CDX), were determined after oral administration of 1000 mg (capsules) on an empty stomach in 12 normal subjects in comparison to cephalexin (CEX). Serum concentrations were measured during a period of 8 h and urine recovery during 24 h. The significant parameters of bioavailability of an orally administered substance were determined. The maximum serum concentrations (ymax) were 38.8 +/- 8.1 mg/l (CEX), 34.6 +/0 7.8 mg/l (CCL), 33.0 +/- 5.4 mg/l (CDX); the areas under the curve were 93.0 +/- 14.8 h . mg/l (CEX), 74.5 +/- 9.9 h . mg/l (CCL), and 108.5 +/- 18.4 h . mg/l (CDX). In a further crossover study with 6 subjects, 1000 mg CEX and CDX were given during a standard breakfast. The ymax of CEX decreased to 23.1 +/- 6.6 mg/l in contrast to CDX with an unchanged ymax of 32.7 +/- 3.4 mg/l.