This study aimed to identify variation in the minimum biocidal concentration (MBC) over time, comparing three commercial super-oxidized solutions with different chemical compositions. In the bactericidal assay, the following bacteria were tested: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), and for each ATCC, one wild-type strain was used. In vitro experiments were performed in triplicate at 0, 60, and 120 days of follow up. A commercial formulation based on sodium and chloride ions (SCSS) was tested using a standard accelerated aging protocol. Data were analyzed with the Friedman and Wilcoxon signed-rank tests. The results showed that super-oxidized solution bases of 20 ppm of sodium (SSS) had a significant change in MBC at 120 days (p < 0.001), whereas SCSS remained stable during the same period (p = 0.18). However, after accelerated aging treatment, the MBC of SCSS increased (p < 0.001). With our proposed approach, the two SSS showed MBC variation at 120 days, whereas SCSS showed stability over time, similar to chlorhexidine, but lost its bactericidal properties after accelerated aging treatment.
Keywords: anti-infective agent; antiseptic; chemical stability; chlorhexidine; microbicide; super-oxidized solution.