Oxolinic acid pharmacokinetics

The pharmacokinetics of FLU and its metabolite 7-OH FLU in sheep tissue was studied using the HPLC method with fluorescence detection (207). Tissue samples were extracted with ethyl acetate. After drying, phosphate buffer (pH 7.8) and hexane were added, and aqueous (lower) phase was injected into an HPLC system. Extraction recovery was 75% for FLU and 60% for 7-OH FLU. The limit of detection was 1 and 4 ytrg/kg for both compounds. The elimination of OXO in eggs (albumen, yolk) was described using an HPLC assay with fluorimetric detection. The limits of quantitation were 5 tg/kg in albumen and yolk. Of the overall oxolinic acid detected in eggs, 95% was concentrated in the albumen. Detectable residues persisted for 9 and 7 days, respectively, in albumen and yolk after the treatment was discontinued (208). Albumen sample was homogenized with water and hydrochloric acid and extracted with ethyl acetate. The supernatant was evaporated and the rest dissolved in mobile phase. Extraction recovery was 65.2%, RSD of 5.3, for a concentration of 10 ig/kg. 

It is recommended for the treaimenl of urinary tract infections caused by strains of Gram-negative bacteria susceptible to these agents. Early clinical studies indicate that the drug pos.sesses pharmacokinetic properties superior to those of either of its predece.ssors. Thus, following oral administration, higher urinary concentrations of cinoxacin than of nalidixic acid or oxolinic acid are achieved. Cinoxacin appears to be more completely absorbed and less protein bound than nalidixic acid. 

Oxolinic Acid. Oxolinic acid, a quinoline antibiotic, is widely used in humans for urinary tract infections. This drug has shown efficacy for the treatment of a variety of gram-negative bacterial diseases in fish however, it has not yet received approval for such use in this country. Recently, studies have investigated the relationship of species differences in metabolism and pharmacokinetics to preferred acclimation temperatures of fish (54). These... 

Table III. Pharmacokinetic Values for Oxolinic Acid in Rainbow Trout (14°C), Warm Water Acclimated Catfish (24°C) and Coldwater Acclimated Catfish (14 0 Following a Single Intravenous Dose (5 mg/kg)...

Water quality has been shown to affect oxolinic acid uptake and its pharmacokinetic parameters when fish are exposed via the water. Endo and Onozawa (59) reported in studies with Ayu that the volume of distribution of... 

SMITH p (2008a), A cost-benefit analysis of the application of pharmacokinetic/ pharmacodynamic-based approaches to setting disc diffusion breakpoints in aquaculture a case study of oxolinic acid and Aeromonas salmonicida Aquaculture, 284,2-18. 

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