Comparison of cytotoxicity of fluoroquinolone antimicrobial eye drops and its effect on their bioavailability

In addition to the breadth of activity of antibacterial medications as well as to their pharmacokinetic and pharmacodynamic properties, their safety and bioavailability represent an important aspect. Currently, there is no consensus on fluoroquinolone toxicity. The aim of the present study was to compare the total cytotoxic effect on corneal epithelium and bioavailability of three antibacterial fluoroquinolone eye drops, registered in the Russian Federation: 1) Oftaquix™ (levofloxacin 5 mg/ml; preservative benzalkonium chloride (BAC) 0.05 mg/ml; produced by Santen Oy, Finland), hereafter “levofloxacin (original)”; 2) Signicef® (levofloxacin 5 mg/ml; preservative BAC 0.1 mg/ml; produced by Sentiss Pharma Pvt. Ltd., India), hereafter “levofloxacin (generic)”; 3) Vigamox® (moxifloxacin® 5 mg/ml; preservative-free; produced by Alcon Laboratories, Inc., USA) hereafter “moxifloxacin” - using in vivo methods and determining the possible effect of preservative presence (in different concentration) or of its absence on reaching the minimal threshold concentrations of the antibiotic in the anterior chamber fluid, using the high-yield liquid chromatography combined with mass-spectrometric detection. The study showed that tested antibacterial medications could exert a cytostatic effect on the corneal epithelium at in vivo conditions and differ in their cytotoxic potential. Benzalkonium chloride presence in Signicef in a concentration twice as high than that of the main medication (Oftaquix) causes a proven by confocal microscopy effect on the corneal epithelium, and this may influence the bioavailability of the medication