Safety and efficacy profiles of different commercial sodium hypochlorite/hypochlorous acid solutions (NaClO/HClO): antimicrobial efficacy, cytotoxic impact and physicochennical parameters in vitro

Background: Sodium hypochlorite (NaCIO, SHC)/hypochlorous acid (HCIO, HCA) wound irrigation solutions have experienced a renaissance in the prevention and treatment of low-level wound infections. They are attributed with lower cytotoxicity and have therefore gained increasing attention in daily clinical practice. Objectives: To determine the cytotoxicity and antimicrobial efficacy of six NaClO/HCE0 wound irrigation solutions. Methods: For cytotoxicity evaluation (based on DIN EN 10993-5), human keratinocytes (HaCaT) and human skin fibroblasts (BJ) were used. Staphylococcus aureus and Pseudomonas aeruginosa were used for antimicrobial efficacy evaluation (based on DIN EN 13727), Solutions were evaluated after 1, 5 and 15 min of exposure, Additionally, physicochemical properties (pH and oxidation-reduction potential values) were investigated. Results: Efficacy and cytotoxicity varied significantly between solutions. Generally, increasing antimicrobial activity was associated with decreasing cell viability. Furthermore, a concentration- and time-dependent impact on pathogens and cells was observed: cytotoxic and antimicrobial activity increased with rising NaClO/HCE0 solution concentrations and extended exposure times. Based on these in vitro evaluations, the following ranking (lowest to highest microbicidal effect and cytotoxic impact) was found: Microdacyn60 (R) (SHC/HCA-M) < Granudacye (R) (SHC/HCA-G) < Veriforte (TM) (SHC/HCA-V) < KerraSol (TM) (SHC-K) < Lavanoe (R) (SHC-L) <<, ActiMarisqorte (R) (SHC/SM-A). Conclusions: The presented results indicate that microbicidal effects are almost always associated with certain negative side effects on cell proliferation. Efficacy and biocompatibility of NaCIO/HCLO solutions depend on their specific formulation and physicochemical properties. The investigations also underline the necessity for exact product- and application-specific efficacy profiles.