Comparison of pharmacokinetics/pharmacodynamics of cefdinir, cefpodoxime proxetil and cefaclor against common bacteria of community acquired infections

Abstract

To compare the pharmacokinetics/pharmacodynamics property of cefdinir, cefpodoxime proxetil and cefaclor against common bacteria of community acquired infections and evaluate the recommended regimens. The antibacterial activities of 3 agents against 238 clinical isolates were determined by standard agar dilution test and the pharmacokinetics of these antibiotics in male healthy volunteers were conducted in Latin-square manner. The time over MIC (T > MIC) of serum antibiotic concentrations were calculated with pharmacokinetic equation and MIC. The value of MIC90 s cefdinir against these bacterial strains except penicillin non-sensitive pneumococci were 0.031-1 mg/L. Cefpodoxime held similar antibacterial activity with cefdinir, but was less potent against staphylococci. Cefaclor had much higher MIC values than other two drugs. After oral administration of 250 mg cefaclor, the drug concentration quickly reached peak concentration of 4.95 mg/L +/- 2.41 mg/L and the eliminative half time was 0.69 h +/- 0.6 h; the Tmax, Cmax and T1/2beta of cefdinir and cefpodoxime after oral administration of 100 mg were 2.5 h +/- 0.48 h, 0.81 mg/L +/- 0.19 mg/L, 1.73 h +/- 0.3 h and 2.38 h +/- 0.43 h, 1.12 mg/L +/- 0.28 mg/L, 1.92 h +/- 0.55 h, respectively. T > MIC of cefdinir in thrice daily administration were longer than 40% of medication interval against most of the tested isolates; no T > MIC period was found in cefpodoxime against staphylococci and the T > MICs of cefaclor after 250 mg oral administration were shorter than expected values against most bacteria. With powerful antibacterial activity, the T > MICs of cefdinir after 100 mg oral administration can meet with the clinical requirement in most infections; PK/PD value of cefpodoxime proxetil against staphylococci is lower than expectancy and 250 mg cefaclor 3 times daily is not enough to the treatment of common community acquired infections, the regimens of cefpodoxime proxetil and cefclor should be furtherly optimized.