BUGNON D, MAJCHERCZYK PA, GIANNONI E, GLAUSER MP, MOREILLON P; Interscience Conference on Antimicrobial Agents and Chemotherapy.

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2000 Sep 17-20; 40: 13.

Chuv, Lausanne, Switzerland

Introduction: During validation of CEF titration by HPLC we observed significant temperature- and plasma-dependent drug degradation in vitro. Since this might bias the results provided to the caretaker, we measured the degradation kinetics for various CEF concentrations and temperatures and established validation procedures at 4 degrees C. Method: Citrated plasma containing CEF was deproteinized by acetonitrile precipitation followed by methylene chloride back-extraction. CEF was separated by HPLC using a C18 column and detected with a diode array. The area under the peak was calculated at 260 nm for CEF.RESULTS: 1 - When all procedures were performed at 4 degrees C, the limit of detection was 0.5 microg/ml, the standard curve was linear from 0.5 to 200 microg/ml, recovery was >/=90%, the intra- and inter-run coefficients of variation and accuracy were <10%, and no degradation was observed over a 12 h period of time. 2 - At 20 degrees C, CEF was irreversibly degraded in plasma with a mean +/- SD half-life (T[1/2]) of 7.3 +/- 2.8 h as assessed in 3 separate experiments, and was independent of drug concentrations in a range 1-160 microg/ml. In contrast, no significant degradation was observed over 12 h when CEF was dissolved in water. 3 - At 37 degrees C, CEF degradation occurred with a mean +/- SD T[1/2] of 1.6 +/- 0.3 h (assessed at 5 different concentrations). 4 - Finally, when parallel kinetics were performed over 12h with the same 50 microg/ml stock of CEF at 4 degrees C, 20 degrees C and 37 degrees C, the temperature-dependent degradation of CEF was confirmed with the T[1/2] decreasing from 126 to 1.9 h between the two extremes. Again, the drug was stable in water. Conlusion: Considering the handling-time required for drug monitoring in patients, reliable CEF titration should only be performed at 4 degrees C. Importantly, the plasma and temperature-dependent degradation of CEF raises serious questions on the reliability of more classic titration by bioassay, as well as on the stability of other drugs. In the present experiments multiple CEF degradation products were detected. Characterizing these metabolites and their biological activity will require further studies.KEYWORDS: Assay; Cefepime; Unstability

Publication Types:

• Meeting Abstracts

Keywords:

• Body Temperature
• Cephalosporins
• Chromatography, High Pressure Liquid
• Humans
• In Vitro
• Temperature
• cefepime
• methods

Other ID:

• GWAIDS0011127

UI: 102248625

From Meeting Abstracts