Determination of quinolone antibiotics in growth media by reversed- phase high-performance liquid chromatography

A simple, accurate, precise, and versatile high-performance liquid chromatographic (HPLC) method was developed and validated for the determination of three quinolone antibiotics in Mueller-Hinton broth. The fluoroquinolone agents studied were ciprofloxacin, ofloxacin, and sparfloxacin; other quinolone agents have been identified using this method but not validated in this matrix (levofloxacin, clinafloxacin, temafloxacin, and trovafloxacin). In addition, several other biological growth mediums have been investigated (human serum, human urine, Todd-Hewitt growth media, Ensure enteral feeding solution, and Haemophilus growth media). This method uses UV detection (280 nm), a simple, one-step protein precipitation extraction, and separation using a C₁₈ column with an isocratic, ion-pairing mobile phase. An appropriate internal standard was obtained by using another quinolone antibiotic of differing retention time. The calibration curves were linear (r² ≤ 0.999) over a concentration range of 0.0625-20.0 μg/ml with a lower limit of quantification of 0.1 μg/ml. The intra-day and inter-day coefficients of variation were less than 15%.