Multiple response optimization of a liquid chromatographic method for determination of fluoroquinolone and nitroimidazole antimicrobials in serum and urine.

Objectives: Development and validation of a sensitive, selective and robust SPE assisted HPLC method for the quantification of fluoroquinolones and nitroimidazoles in human serum and urine using design of experiments methodology.
Design and Methods: Design of experiments was employed for method optimization (Box-Behnken design) and robustness testing (Plackett-Burman design). Sample preparation involved a simple solid phase extraction, which offered a satisfactory recovery (≥94%). Analytes were separated on a phenyl hexyl column with mobile phase comprising water, acetonitrile and triethyl amine in ratio of 74:26:0.15 v/v, with a flow rate of 1.1mL/min.
Results: Calibration curves were linear over selected range (≥0.995) for all the analytes. The method was sensitive with detection limits of 0.06-0.16μg/mL in serum and urine samples. Inter and intra-day precision data (in terms of %RSD) was found to be less than 7%. Stability studies were carried out to assess freeze thaw, short term and long term stability and all analytes were found to be stable. The method was successfully applied for determination of antimicrobial drugs in spiked serum and urine.
Conclusion: The obtained results corroborated the potential of the proposed method for determination of all the four antimicrobial drugs in therapeutic drug monitoring, bioequivalence and drug-drug interaction studies.
(Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)