Determination of trovafloxacin and marbofloxacin in sheep plasma samples by HPLC using UV detection

A simple and rapid high performance liquid chromatographic method was developed, validated and applied for the simultaneous determination of marbofloxacin (MBX) and trovafloxacin (TVX) in sheep plasma. Samples were extracted with 20% perchloric acid and MBX and TVX were separated on a C18 column using a gradient mobile phase system consisting of 17.5 mM of NaH2PO4 and 1.5 mM of tetrabutylammonium hydroxide aqueous solution, pH 3 (A) and 50% acetonitrile and 50% methanol (B), with UV detection at 293 and 270 nm. The retention times of MBX and TVX were 4.9 and 6.6 min respectively. The detection and quantification limits for MBX and TVX were 2 ng/mL and 10 ng/mL respectively for both compounds. The calibration curves were linear over a concentration range of 10–50,000 ng/mL for both antibiotics. The linearity, precision, accuracy, recovery and stability of the assay were evaluated from spiked sheep plasma. The method was successfully applied to sheep plasma samples obtained from MBX and TVX pharmacokinetic studies.

► We developed an HPLC method for assay of marbofloxacin and trovafloxacin in biological fluids.
► These drugs show potential for treatment of respiratory diseases in farm animals.
► The bioassay method was required for ongoing pharmacokinetic and pharmacodynamic trials in sheep.
► The method was validated for routine use with ovine plasma over the range 10–50,000 ng/mL.
► We include pharmacokinetic profiles following IV administration of both drugs in sheep.