To support dosing regimens of pradofloxacin, it is important to know the concentrations in the relevant tissues for these infections. A two-way crossover study compared the pharmacokinetics of pradofloxacin and doxycycline in serum, saliva and tear fluid in cats. Samples of serum, saliva and tear fluid were taken after a single oral dose of doxycycline or pradofloxacin at 5 mg/kg body weight.
Comparison of the pharmacokinetics of pradofloxacin and doxycycline in serum, saliva and tear fluid in cats after a single oral administration of 5 mg/kg
Pharmacokinetic parameters (mean ± SD) of pradofloxacin (PRA) and doxycycline (DOX)
AUC, area under the curve, Cmax, maximum serum concentration, MRT, mean residence time; Tmax, time of Cmax; t1/2, terminal half-life; -, parameter could not be calculated
The AUC0-24 for pradofloxacin recovered in tear fluid was higher than the AUC0-24 in serum, which indicates the excellent penetration of the antibiotic into tear fluid. Concentrations of pradofloxacin in tear fluid markedly exceeded serum concentrations within the first hour of administration. A similar pattern was observed for saliva showing a very good penetration into this fluid. Doxycycline was present in high concentrations in serum samples, but did not exceed the limit of quantification in saliva at any time point. Doxycycline only slightly exceeded the limit of quantification in tear fluid.