Plasma and urine pharmacokinetics of intramuscular marbofloxacin in canines

Abstract

Plasma and urinary disposition of marbofloxacin was studied in canines (n = 6) after intramuscular administration of 2 mg/kg. At different times post-administration, blood samples were collected until 24 h, and urine samples, only from male dogs (n = 4) at 48 12, and 24 h. Liquid-liquid extraction of analyte with water, methanol, and centrifugation at 13500 rpm at 4 °C were performed. Separation and quantification were made using HPLC by reverse phase isocratic elution with a C18 column, fluorescence detector at 295 nm excitation and 490 nm emission, and a mobile phase consisting of water, acetonitrile, and triethylamine. Temporary plasma concentrations were analyzed with non-compartmental PK Solution 2.0 software. The results obtained indicate rapid absorption, as well as rapid and wide distribution. Cl and values of t½β and MRT indicate slow clearance and prolonged stay. The study evidenced plasma concentrations up to 24 h, which exceed the MIC of relevant pathogens. The AUC/MIC ratio indicates efficacy against microorganisms with MIC ≤ 0.15 μg/ml. Urinary levels of marbofloxacin are more significant than plasmatic levels. However, new studies are required to assess their use with the tested dose and route of application.