Simultaneous determination of 12 beta-lactam antibiotics in human plasma by high-performance liquid chromatography with UV detection: application to therapeutic drug monitoring

Abstract

A rapid and specific high-performance liquid chromatography method with UV detection (HPLC-UV) for the simultaneous determination of 12 beta-lactam antibiotics (amoxicillin, cefepime, cefotaxime, ceftazidime, ceftriaxone, cloxacillin, imipenem, meropenem, oxacillin, penicillin G, piperacillin, and ticarcillin) in small samples of human plasma is described. Extraction consisted of protein precipitation by acetonitrile. An Atlantis T3 analytical column with a linear gradient of acetonitrile and a pH 2 phosphoric acid solution was used for separation. Wavelength photodiode array detection was set either at 210 nm, 230 nm, or 298 nm according to the compound. This method is accurate and reproducible (coefficient of variation [CV] < 8%), allowing quantification of beta-lactam plasma levels from 5 to 250 μg/ml without interference with other common drugs. This technique is easy to use in routine therapeutic drug monitoring of beta-lactam antibiotics.

Figures

Fig. 1.

HPLC chromatograms of an internal quality control with 10 μg/ml of each antibiotic at 298 nm (a), 230 nm (b), and 210 nm (c). Values after the antibiotic names are retention times.

Fig. 2.

HPLC chromatograms of a blank plasma sample at 298 nm (a), 230 nm (b), and 210 nm (c). Retention times for the different compounds are indicated by the positions of the names.

Fig. 3.

Chromatograms of extracted plasma samples from patients treated with amoxicillin (residual concentration, 33.5 mg/liter) (a) and cloxacillin (residual concentration, 15.3 mg/liter) (b).

Fig. 4.

Retention times of beta-lactam antibiotics by pH of the mobile phase.