Pharmacokinetics of topically applied sparfloxacin in rabbits

Abstract

Fluoroquinolones are antimicrobial agents that have a broad spectrum of activity and are widely used against many of the ocular pathogens, responsible for conjunctivitis, blepharitis, corneal ulcers etc. The aim of our study was to evaluate the ocular pharmacokinetics of sparfloxacin (0.3% w/v) in the aqueous humour of rabbits. Pharmacokinetics of topically administered sparfloxacin were determined after a single application of 50 microl topically. The aqueous humour samples were collected at 0, 0.25, 0.5, 1, 2, 3, 4, 5 or 6 hours after instillation. High Performance Thin Layer Chromatographic method was used to analyse the drug concentration in the aqueous humour samples. Fifteen minutes after the instillation of 50 microl of sparfloxacin 0.3% solution, the mean concentration in aqueous humour was found to be 1.4 microg/ml, which reaches the peak level of 3.7 microg/ml after 1.3 hours. At 6 hours, the sparfloxacin aqueous levels were 0.562 microg/ml. The clinical efficacy was predicted based on the Maximum Concentration (Cmax): Minimum Inhibitory Concentration (MIC) and Area Under the Concentration-time curve (AUC):MIC ratios. The sparfloxacin levels in aqueous humour of rabbits are sufficiently high up to the 6 hours after instillation in the conjunctival sac to provide bactericidal effect against most of the ocular pathogens. Both Cmax:MIC and AUC:MIC ratios are high enough to provide bactericidal effect against most of the ocular pathogens. Sparfloxacin (0.3%) ophthalmic preparation has excellent penetration through cornea.