The dilution of benzalkonium chloride (BAK) in the tear Film
- 158 Downloads
The claim that benzalkonium chloride (BAK) synergistically enhances the antibiotic efficacy of gatifloxacin ophthalmic solution 0.3% (preserved with 0.005% BAK [50 μg/mL), Zymar; Allergan Inc., Irvine, Calif, USA) has been the subject of several studies. The purpose of this prospective clinical study was to test the hypothesis that BAK would be significantly diluted shortly after topical ocular administration and would thereafter have little or no effect on the enhancement of the antibiotic efficacy of commercial gatifloxacin on the ocular surface. This hypothesis was tested by investigators who measured the concentration of tear film BAK at successive time points after topical administration of commercial gatifloxacin. After subjects (N=10) received 5 separate instillations of a single 35-μL drop of gatifloxacin 0.3% ophthalmic solution in each eye, tear samples were collected at 30 sec, 1 min, 3 min, 5 min, and 20 min, with the use of graduated 5-μL glass microcapillaries. A validated high-performance liquid chromatography method was used to measure the concentration of BAK in each tear sample. The results showed rapid BAK dilution to 6.4 μg/mL, 3.2 μg/mL, 1.4 μg/mL, below the detection limit, and below the detection limit at 30 sec, 1 min, 3 min, 5 min, and 20 min after instillation of a single 35-μL drop of gatifloxacin. Because such rapid dilution reduces the concentration of BAK to near zero in minutes and does not allow the time (1 h) required for effective bacterial kill power, BAK is not expected to have a clinically significant effect on enhancement of the antimicrobial efficacy of gatifloxacin on the human ocular surface.
Keywordsbenzalkonium chloride (BAK) gatifloxacin fluoroquinolone tear film preservative kill power antimicrobial antibiotic
Unable to display preview. Download preview PDF.
- 3.Schlech BA, Sutton A, Rosenthal RA, et al. Antimicrobial preservative effectiveness of Vigamox.Invest Ophthalmol Vis Sci. 2004; 45: 4913. [E-abstract]Google Scholar
- 4.Blondeau JM, Borsos AD. Antimicrobial efficacy of gatifloxacin with and without benzalkonium chloride compared with moxifloxacin against methicillin-resistantStaphylococcus aureus.Invest Ophthalmol Vis Sci. 2006; 47(suppl): 1903. [E-abstract]Google Scholar
- 5.Borsos SD, Blondeau JM. Antimicrobial efficacy of gatifloxacin with and without benzalkonium chloride compared with moxifloxacin against common ocular pathogens.Invest Ophthalmol Vis Sci. 2006; 47(suppl): 1892. [E-abstract]Google Scholar
- 8.Owen GR, McCarey BE, Edelhauser HF. Non-invasive fluorophotometry assessment of corneal epithelial permeability after exposure to Vigamox™ or Zymar™.Invest Ophthalmol Vis Sci. 2004: 45(suppl): 4902.Google Scholar