Penetration of Enrofloxacin in Aqueous Humour of Avian Eyes.

Enrofloxacin has been shown to be appropriate to treat bacterial eye infections in mammals. However, the anatomy and physiology of the avian eye substantially differ from those in mammals, and pharmacokinetic data substantiating the clinical efficacy of enrofloxacin in birds are still lacking. In total, 40 chickens (Gallus gallus, Lohman Selected Leghorn) received single intramuscular administration of enrofloxacin at a dosage of 25 mg/kg body weight (BW). Serial blood and aqueous humour samples were taken at 12 different time points after administration (0-60 min and 2-32 h) and were analysed for their fluoroquinolone concentrations using a competitive enzyme immunoassay. The metabolization of enrofloxacin to ciprofloxacin was determined using liquid chromatography-mass spectrometry. The maximum serum concentrations of fluoroquinolones were observed at the time point of 2.82 ± 0.1 h and amounted to 10.67 ± 0.5 µg/mL. Fluoroquinolones redistributed to a minor extent into the aqueous humour reaching maximum concentrations of 4.52 ± 1.2 µg/mL after 7.54 ± 1.0 h of drug administration. The mean residence time (MRT), volume of distribution (Vd), and terminal half-life (t1/2 ß) were 1.68-, 2.84-, and 2.01-fold higher in aqueous humour than in serum, indicating that fluoroquinolones were trapped in aqueous humour. Enrofloxacin was only marginally metabolized into ciprofloxacin. A single intramuscular injection of a therapeutical dose of enrofloxacin (25 mg/kg BW) thus generated sustained and therapeutically active levels of enrofloxacin in the aqueous humour of chicken eyes.

Enantiomeric separation by capillary electrochromatography using monolithic capillaries with sol-gel-glued cyclodextrin-modified silica particles.

By an on-column sol-gel process, a chiral monolithic stationary phase was prepared by the fusion of permethyl-beta-cyclodextrin-silica (Chira-Dex-silica) particles and by linking them to the internal capillary wall. The resulting monolith is stable toward voltage (30 kV) and pressure (300 bar) and possesses a high efficiency (up to 100,000 theoretical plates per meter). Efficient enantiomeric separation of various chiral compounds by pressure-supported capillary electrochromatography (CEC) was achieved. When comparing this method to capillary liquid chromatography (LC) employing the same column in an unified equipment, CEC shows a twofold higher column efficiency at comparable elution times and hence better resolution factors.