Abstract
Abstract: :
Purpose:The addition of preservatives to eyedrops has become a standard procedure to prevent microbiological contamination, even though allergic reactions and corneal epithelial disorders have been attributed to these agents. We recently developed a multidose eyedrops container fitted with a membrane filter (PF container) in order to obviate the requirement for preservative. We have now investigated the efficacy of this new type of container with regard to prevention of microbial contamination. Methods: PF containers fitted with a polyethersulfone filter (pore size, 0.22 µm) were studied. Brevundimonas diminuta (standard strain for filtration sterility test; 106 to 107 colony–forming units/mL) in phosphate–buffered saline was used for laboratory experiments. PF containers containing carteolol chloride, betamethasone sodium phosphate, or sodium cromoglicate were also provided to 76 patients for disease treatment and were recovered after use for 1 to 2 weeks for analysis of the cap, tip, membrane filter, and solution for bacteria. Results:No B. diminuta bacteria were detected in the solution dispensed from any of 10 bottles containing the test bacterial suspension. Similarly, no bacterial contamination of a soybean casein digest placed in 10 containers was detected after the attempted aspiration of B. diminuta suspension by squeezing the bottles. Analysis of the PF containers used by patients revealed the presence of Staphylococcus, Bacillus, or other bacterial species in the inside of the cap (9%), on the tip (30%), and on the external surface of the membrane (14%), but no microbes were detected in the solution. Conclusions:Use of a PF container for eyedrops prevented microbial contamination of the solution, demonstrating that such containers are safe for clinical use without preservatives.
Keywords: Staphylococcus • bacterial disease • microbial pathogenesis: experimental studies