Abstract
Purpose:
Ocular drug formulations delivered from multidose eye drop dispensers must contain an effective microbicide to maintain sterility. However, prolonged use of eye drops with soluble microbicides frequently produces epithelial cell toxicity. We assessed the effects of a novel microbicidal polycationic polymer, p-DADMAC, bound to polyurethane foam sponge or cellulose fibers to maintain sterility of eye drop formulations in multidose eye drop dispensers.
Methods:
A circular pad of gauze or polyurethane forma with bound pDADMAC was placed in the bottom of an eye drop container containing 10 ml of nutrient media. 10^6 CFU of Staphylococcus aureus was added to the fluid and aliquots were taken a 1, 6, 12 and 24 hours and grown on blood agar plates.
Results:
There was 100% kill of the bacteria at all time points
Conclusions:
pDADMAC bound to gauze or polyurethane foam sponge rapidly sterilized the contents of the eye drop bottle without leaching into the fluid. This technique avoids adding toxic preservatives such as BAK in the medication solution which can adversely affect the cornea and adnexa.