Ocular Microbiology and Immunology Group
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2014 OMIG Abstract 6

Put the Preservative in the Bottle, Not the Eye!
Richard A. Eiferman, MD¹; Phat L. Tran, PhD²; Ted W. Reid, PhD²;
Gregory S. Schultz, PhD³, Christopher Batish, PhD^3
1University of Louisville; ²Texas Tech University; ³University of Florida

Purpose: Multi-dose ophthalmic eye drop formulations require the addition of a preservative to reduce the risk of bacterial or fungal growth in the solution that can infect the eye. Unfortunately, preservatives can cause irritation and toxicity when applied to the eye, especially with chronic use. To address this problem, we assessed the microbicidal effects of a high molecular weight, polycationic (polyquat) polymer (polydiallyldimethylammonium chloride, pDADMAC) that was immobilized to polyurethane (PU) “sponge-like” materials that could be placed inside eye drop containers.

Methods: Solutions (500 μl) of PBS containing 10⁶ to 10⁷ CFU of Staphylococcus aureus (AH133), Pseudomonas aeruginosa (PAO1) or Acinetobacter baumannii (patient isolate) were added to 1 inch² PU foam squares with and without immobilized pDADMAC and incubated at room temperature. After 5 minutes, 1 hr, 2 hrs and 4 hrs of incubation, the PU foam squares were transferred to sterile 15 ml conical tubes and levels of viable bacteria bound to the PU foams were determined by extracting the PU foams with sonication and vortexing followed by standard agar plate dilution methods. The studies were performed in triplicate.

Results: PU foam coated with immobilized pDADMAC killed all S. aureus after 5 minutes exposure, killed all A. baumannii after 1 hr exposure, and killed all P. aeruginosa after 2 hours exposure while control PU foam did not reduce bacterial levels.

Conclusion: PU foam with immobilized pDADMAC may be an alternative to soluble preservatives for repeated dose eye drop formulations.

Disclosure: 1, C,O;2 C;3,C, 4 C,0;4C,O

2014 Agenda and Abstracts | < Previous | Next >