April 2010
Volume 51, Issue 13
ARVO Annual Meeting Abstract  |   April 2010
Effectiveness of Ophthalmic Preservatives; Comparing Benzalkonium Chloride and Sofzia® Preservative System
Author Affiliations & Notes
  • G. Ryan, Jr.
    Parenteral Center of Emphasis, Pfizer Inc., Groton, Connecticut
  • J. Fain
    Clinical Development and Medical Affairs, Pfizer Ophthalmics, Chicago, Illinois
  • C. A. Lovelace
    #118, Pfizer Inc, Kennesaw, Georgia
  • K. M. Gelotte
    Parenteral Center of Emphasis, Pfizer Inc., Groton, Connecticut
  • Footnotes
    Commercial Relationships  G. Ryan, Jr., Pfizer Inc., E; J. Fain, Pfizer Inc., E; C.A. Lovelace, Pfizer Inc., E; K.M. Gelotte, Pfizer Inc., E.
  • Footnotes
    Support  None.
Investigative Ophthalmology & Visual Science April 2010, Vol.51, 3194. doi:
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      G. Ryan, Jr., J. Fain, C. A. Lovelace, K. M. Gelotte; Effectiveness of Ophthalmic Preservatives; Comparing Benzalkonium Chloride and Sofzia® Preservative System. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3194.

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      © ARVO (1962-2015); The Authors (2016-present)

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Although there have been reports/studies suggesting that benzalkonium chloride (BAK) in topical ophthalmics is detrimental to cornea epithelial cells, multiple clinical studies have provided significant evidence supporting the safety of BAK. Despite this controversy, it remains the most commonly used preservative in ophthalmic products largely due to proven efficacy as an antimicrobial agent.To evaluate the differences from a microbial viewpoint, this study was designed to characterize the antimicrobial performance characteristics of two commonly used topical IOP lowering products which use different preservation systems, Xalatan® (Pfizer) using Benzalkonium chloride (BAK) and Travatan Z® (Alcon) with a proprietary ionic buffer system (Sofzia®).


Each product was tested as described in European Pharmacopeia Chapter 5.1.3, "Efficacy of Antimicrobial Preservation".


BAK containing Xalatan® met EP-A criteria by immediately reducing all bacterial challenge organisms to the test sensitivity and fungal challenges within the first 6 hours. Travatan Z® however was not able to meet the EP-A criteria. Complete bacterial reduction by Travatan Z® was not shown until 7 days into the test, and fungal reduction never exceeded the requisite 2 logs during the 28 day test.


Xalatan® topical solution exhibited more effective microbial protection compared to Travatan Z® when evaluating rates of microbial reduction, time to no recovery for all challenges and evaluation against EP-A criteria.The rapid and complete reduction of all microbial challenges supports our conclusion that microbial protection provided by BAK (Xalatan®) exceeds that of Sofzia® preservative system (Travatan Z®) and provides a more protective environment in the event of contamination and subsequent exposure to microorganisms during use.  

Keywords: intraocular pressure 

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