Pharmacokinetic studies of amoxicillin, potassium clavulanate and their combination

Pharmacokinetic parameters after oral administration of 500 mg amoxicillin, 125 mg potassium clavulanate and 625 mg of their combination (augmentin) were determined in a randomized crossover study in ten healthy volunteers. The absolute bioavailability of amoxicillin (AUCoral/AUCi.v.) was 0.70 +/- 0.12. The mean maximum serum concentration of amoxicillin was 6.5 +/- 1.6 mg/l after administration alone and 6.5 +/- 1.4 mg/l after administration in combination. The respective values for potassium clavulanate were 3.4 +/- 1.4 mg/l and 2.8 +/- 1.1 mg/l. With both substances there was no significant difference between the pharmacokinetic parameters after administration alone and in combination. The AUC for amoxicillin was 19.5 +/- 5.4 h x mg/l after administration alone and 23.2 +/- 10.6 h x mg/l after administration in combination. The respective value for potassium clavulanate were 7.8 +/- 3.2 h x mg/l and 7.3 +/- 2.0 h x mg/l.