A New Disinfectant: Superoxidized Water

CDC – Center for Disease Control and Prevention, Volume 7, Number 2—April 2001

 

The concept of electrolyzing saline to create a disinfectant is appealing because the basic materials, saline and electricity, are cheap and the end product (water) is not damaging to the environment. A commercial adaptation of this process, Sterilox, is available in the United Kingdom. The mode of action is not clear but probably relates to a mixture of oxidizing species. The main products are hypochlorous acid at a concentration of approximately 144 mg/L and free chlorine radicals. This disinfectant is generated at the point of use by passing a saline solution over titanium-coated electrodes at 9 amps. The product generated has a pH of 5.0-6.5 and an oxidation reduction potential of >950 mV. Equipment to produce the product may be expensive because parameters such as pH, current, and redox potential must be closely monitored. The solution has been shown to be nontoxic to biological tissues. Although the solution is claimed to be noncorrosive and nondamaging to endoscopes, one flexible endoscope manufacturer has voided the warranty on its endoscopes because superoxidized water was used to disinfect them (12).

The antimicrobial activity of this new sterilant has been tested against bacteria, mycobacteria, viruses, fungi, and spores (1315). Recent data have shown that freshly generated superoxidized water is rapidly effective (<2 minutes) in achieving a 5-log10 reduction of pathogenic microorganisms (Mycobacterium tuberculosis, M. chelonae, poliovirus, HIV, MRSA, Escherichia coli, Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa) in the absence of organic loading. However, the biocidal activity of this disinfectant was substantially reduced in the presence of organic material (5% horse serum) (14). Additional studies are needed to determine if this solution may be used as an alternative to other disinfectants.

High-level disinfectants

High-level disinfectants (HLD)/chemical sterilants are used primarily for processing of medical devices, although a few HLD are indicated for use on environmental surfaces. These products must have FDA 510(k) clearance to be legally marketed in the United States. A listing of 510(k) clearances for HLDs by active agent type and year (2002-2012) is presented in Table 1 above. Eighteen HLD products have been cleared by the FDA in the last 10 years. Whereas glutaraldehyde formulations continue to be developed and marketed, more oxidizing chemical formulations (H2O2 and peracetic acid [PAA]) have been cleared during this time frame than any of the other formulations listed.

Table 1HLD/chemical sterilants FDA 510(k) cleared 2002-2012 by type of active agent, based on search of available data bases15, 16
Active agentYear 
20022003200420052006200720082009201020112012 
Glutaraldehyde111 
Glutaraldehyde + IPA111 
OPA111 
H2O21 
PAA121 
H2O2/PAA11 
Hypochlorous acid/hypochlorite11 

IPA, isopropyl alcohol; OPA, ortho-phthalaldehyde; PAA, peracetic acid.