The efficacy of a topical ocular antibiotic relies primarily on its structure, its mechanism of action, and its penetration to the intended site of action. Rapid penetration into the target tissue can translate to greater efficacy and more expedient elimination of bacteria. Effective penetration of medication can therefore have a depot effect and aid in minimizing the spread of infection and reducing the likelihood of bacterial development of resistance.
Clinicians must recognize the importance of tissue-concentration data and the fact that gathering them requires conjunctival biopsy to assess the relative abilities of ophthalmic agents to maintain effective concentrations in the conjunctiva. This study presents a new dual-biopsy technique that has the potential to become a universally approved, standardized means of evaluating topical ocular antibiotics. The purpose of this study was to determine the concentrations of 0.5% moxifloxacin (Vigamox; Alcon Laboratories Inc, Fort Worth, Tex), 0.3% ciprofloxacin (Ciloxan; Alcon Laboratories Inc), 0.3% gatifloxacin (Zymar; Allergan Inc, Irvine, Calif), 0.3% ofloxacin (Ocuflox; Allergan Inc), and 0.5% levofloxacin (Quixin; Santen Incorporated, Napa, Calif) ophthalmic solutions in conjunctival tissue following a single dose of study medication 20 minutes after instillation.
Wagner RS, Abelson MB, Shapiro A, Torkildsen G. Evaluation of Moxifloxacin, Ciprofloxacin, Gatifloxacin, Ofloxacin, and Levofloxacin Concentrations in Human Conjunctival Tissue. Arch Ophthalmol. 2005;123(9):1282-1283. doi:10.1001/archopht.123.9.1282