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Deborah McGrath, Kimberly A Millard, Damien Cordero, Timothy W Morris; Simultaneous Determination of the Rate of Disinfection and Peroxide Neutralization of a Novel Hydrogen Peroxide Disinfecting System. Invest. Ophthalmol. Vis. Sci. 2014;55(13):6052.
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The addition of a platinum modulating compound (PMC) has been shown to delay hydrogen peroxide neutralization and increase the total Area Under Curve (AUC) in a novel one-step system that utilizes a lens case with a platinum (Pt) coated disk. This study investigated the simultaneous rate of disinfection and total AUC within the first 30 minutes of neutralization using a novel one-step hydrogen peroxide system containing a PMC and a marketed one-step disinfecting system without a PMC.
Stand-alone biocidal efficacy test methods were based upon the ISO 14729 testing standard modified to permit testing of each product at 15 min, 30 min and 60 min time points in separate lens cases. Challenge inocula were prepared in 10% organic soil and diluted to a final test concentration of ~ 5 x 105 CFU/mL in 10 mL of each solution/lens case combination. At each time point, samples were neutralized with catalase, serially diluted, and plated to enumerate surviving microbes and calculate log reduction values. An additional sample was taken from each case and peroxide concentration was determined by standard redox titration. Statistical comparisons among each test solution/lens case combination for both total AUC and log reduction were analyzed using Minitab 16 release software.
The total AUC within the first 30 minutes for the novel hydrogen peroxide system with a PMC was significantly higher (p-value = 0.038) than the marketed peroxide solution without a PMC. Log reduction values at the 30 minute time point for control versus test solutions ranged from 3.2 - 4.7 for S. aureus, 4.8 - 4.8 for P. aeruginosa, 3.3 - 4.6 for S. marcescens, 1.1 - 1.3 for C. albicans and 3.3 - 3.6 for F. solani, respectively for the marketed and novel peroxide system.
The novel one-step hydrogen peroxide solution showed a faster rate of disinfection for S. aureus, S. marcescens and F. solani. These values correlate with the higher AUC value that was determined within the first 30 minutes of disinfection. Although after the total recommended disinfection time, both solutions exceed the primary acceptance criteria for all organisms tested, further investigation is warranted to determine any biological benefits of an increased rate of disinfection
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