Research & Evidence on Hypochlorous Acid

HOCl solution can be considered to make a positive contribution to the eradication of infections in revision hip arthroplasty and can be an effective and safe alternative to other irrigation solutions.

Hypochlorous acid demonstrated equivalent efficacy and safety compared with 5% Sulfamylon when used as the postoperative topical dressing for skin grafts. Hypochlorous acid was more cost-effective.

In conjunction with previously demonstrated superiority to other commonly used antimicrobial irrigations (povidone iodine, chlorhexidine gluconate, triple antibiotic solution) pure, HOCl stabilized in amber glass may be the preferred pocket irrigation solution based on its safe, rapid, and effective antimicrobial and anti-biofilm properties. 

Hypochlorous acid rinses are proposed for plaque control and as a wound healing agent for its use in oral health, due to its low toxicity, high antimicrobial efficacy, anti-inflammatory effect, induction to cell proliferation and its background as a topical solution in the antisepsis of wounds in clinical medicine. HOCl has also the ability to oxidize the amino acid taurine and induce the formation of chlorine-taurine (TauCl) which has broad spectrum antimicrobial activity. The TauCl has a significant protective effect on tissues because it can inhibit the production of inflammatory mediators and thereby contribute to the processes of tissue protection.

Low concentration hypochlorous acid is safe for the oral mucosal epithelium and has antimicrobial efficacy similar to that of chlorhexidine.

In addition to their anti-infectious properties, the end-products of the PMN respiratory-burst, HOCl and TauCl, possess, at low concentrations, very interesting and complementary activities which modulate crucial phases of the inflammatory process, cell turnover and periodontal tissue healing. Such activities may be summarized as follows: (1) neutralization of antigens and pathogenic agents following chlorination and/or their oxidation; (2) direct neutralization of metalloproteinases, IL-5 and IL-6; (3) enhancement of inflammatory mediator binding to 2-macroglobulins; and (4) reduction of the binding of growth factors to 2-macroglobulins.

This study showed a similar reduction of the mean of PD [pocket depth] and CAL [clinical attachment level] in CHX and HOCl protocols. However, in gain >3 mm of CAL, HOCl tended to show a significant reduction compared to CHX. We could hypothesize that reducing the recolonization of periodontal microorganisms may favor tissue healing. However, HOCl has been shown to have an anti-inflammatory effect in atopic dermatitis, and it is favored when combined with taurine. The anti-inflammatory effect of HOCl could also be related to the improvement of healing of periodontal tissues, unlike the CHX, which has been associated with a delay in the proliferation of gingival fibroblasts and the production of collagenous and non-collagenous proteins.

In conclusion, HOCl rinses have an initial effect on bacterial viability in saliva and can be used to reduce the bacterial count in saliva.

[Our] study showed that a low-level hypochlorous acid solution exhibited strong bactericidal activity on four anaerobic bacteria (P. gingivalls, P. intermedius, P. nigrescens, F. nucleatum) responsible for periodontitis and five facultative anaerobic bacteria (S. mutans, S. sobrinus, S. godonii, S. oralis, S. salivarius).

The gargling with slightly acidic hypochlorous acid (HOCl) was found to be effective in the halitosis test, O’Leary index measurement, and Snyder test, and especially, the phase-contrast microscopy showed that Filamentous and Spirochetas, the bacteria that cause periodontal diseases, decreased remarkably. To prevent oral diseases, effective oral care can be achieved by managing dental plaque, decreasing the dental caries activity, and reducing the acid production ability of bacteria. The use of HOCl as a mouthwash rather than CHX, which is commonly used in dental practice but has side effects, will contribute to the prevention of oral diseases and will inhibit the adhesion of dental plaque to the teeth.

HOCl acid has also been described as a wound cleanser. It has been shown to significantly reduce bioburden in peripheral open wounds, thereby assisting in their closure. However, intra-abdominal placement of HOCl has never been described to treat the open septic abdomen. The combination of the ABNPWT device system and the VAC Veraflo device allows for delivery of a set amount of irrigation in a timed manner. This combination in a patient with a septic abdomen proved pivotal in the resolution of the gross mucopurulence visualized in the abdomen.

One day after administration of the hypochlorous acid, the fever began to subside, suggesting that this solution was able to adequately destroy the infecting microorganisms. The patient rated his pain during this procedure as 2/10. The infection had cleared within 2 weeks, and a swab culture found no microbial growth. The wound volume was reduced by more than 90% after 5 weeks, and final wound closure was achieved after 6 weeks.

In vitro studies of 0.01% HOCl were observed to have equal or more efficacious antiseptic properties compared with isopropyl alcohol (IPA), chlorhexidine gluconate (CHG), and povidone-iodine (PVP-I).

In vitro studies demonstrate HOCl is effective against all human bacterial, viral, and fungal pathogens.

Experiences from clinical practice suggest that hypochlorous acid (HOCl) used as adjuvant treatment can shorten the time to clinical resolution of blepharitis, particularly in relation to the ophthalmic complications that often occur with a blepharitis diagnosis. In addition, in clinical practice, HOCl adjuvant treatment also resulted in a viable option for the management of ophthalmic disorders other than blepharitis.

On average, subjects reported a 10-point decrease in OSDI score on Day 14 (from 37 to 27) and a further improvement of 5 points on Day 30 (22). A similar response was seen with the EIQ, where subjects showed a 20.5-point decrease over 30 days (from 39 to 18.5). Corneal and conjunctival staining was also reduced over 30 days (from grade 4 to 3 and grade 3 to 1, respectively). Demodex counts were reduced by nearly half over the study period.

A new treatment method for infective eye conditions is proposed which does not rely on the use of topical antibiotics. HOCl, when applied at 80mg/l pH5.4, is profoundly effective and well tolerated in cases of bacterial or viral conjunctivitis.

The application of a saline hygiene solution preserved with pure HOCl acid reduced the bacterial load significantly without altering the diversity of bacterial species remaining on the skin under the lower eyelid.

Acidification of the wound by acidic buffers was found to be an effective strategy to improve wound healing. A significant improvement in wound healing parameters was observed as early as 2 days post-treatment with acidic buffers compared to controls, with faster rate of epithelialization, wound closure and higher levels of collagen at day 7. pH is shown to play a role in mediating the rate of wound healing, with acidic buffers formulated at pH 4 observed to stimulate faster recovery of wounded tissues than pH 6 buffers. Our study shows the importance of maintaining an acidic wound microenvironment at pH 4, which could be a potential therapeutic strategy for wound management.

In these case study presentations, HOCl appears to be effective as a potent DFU antiseptic agent with anti-inflammatory and debridement properties. It is inexpensive, easy to use, safe, reduces odour and pain, as well as exudate. It is also not painful to apply, assisting in an elevated level of patient compliance.

Care of patients with burns is complex, could be lengthy and could be complicated by infection, especially if the prevailing bacteria are present as biofilms. This complication can be anticipated and treated with the use of HOCl, an effective agent against planktonic and biofilm bacteria. Furthermore, its effect on the modulation of inflammation ultimately yields improved outcomes. The patient in this case study, despite the formation of biofilm and inflammation, responded well to the local application of and daily dressing with HOCl and gauze. The results suggest that treatment of wounds with HOCl should be investigated for all burn cases where the wounds are not following the normal wound healing trajectory according to the wound healing phases.

Hypochlorous acid irrigation with ultrasound debridement reduced bacterial growth in chronic open wounds more efficiently than saline alone. Postoperative wound closure outcomes suggest a remarkable reduction in wound complications after wound debridement using hypochlorous acid irrigation with ultrasound versus saline alone.

This study demonstrates immediate and durable antimicrobial action and beneficial effect on acute wound healing after irrigation and treatment with a stabilized hypochlorous acid formulation.

This stabilized form of hypochlorous acid (NVC-101) could have potential application as an antimicrobial wound irrigation and treatment solution if its effective pH range can be maintained in the clinical situation. NVC-101 solution was equally effective at pH 3.5 or 4.0 and more efficient soon after its application. As opposed to other antimicrobials investigated in this animal model, NVC-101 controls the tissue bacterial bioburden without inhibiting the wound healing process.

The stabilized HOCl solution had dose-dependent favorable effects on fibroblast and keratinocyte migration compared to povidone iodine and media alone. These features lead to a stabilized HOCl solution as an ideal wound care agent.

Topical formulations of stabilized, pH-neutral HOCl (e.g., solution, gel, spray) have been evaluated in several studies demonstrating both antimicrobial effects and therapeutic benefit in many cutaneous disorders, including seborrheic dermatitis, atopic dermatitis-associated pruritus, acne vulgaris, diabetic foot ulcers, and hypertrophic scars/keloids. Topical HOCl appears to be well tolerated and safe, without any major adverse events reported.

HOCl gel shows promise as a new topical antimicrobial for wounds, especially due to its ability to inhibit P. aeruginosa.

This study suggests that the use of HOCL 0.01% spray after Betadine® 5% for IVI prophylaxis will offer improved patient comfort as a rinse for Betadine®. The known spectrum of antiseptic coverage provided by HOCl 0.01% spray was equal to or better than Betadine®, and affects the majority of the pathogens commonly implicated in endophthalmitis. This research reports on the novel use of HOCL 0.01% as an ocular surface antiseptic.

Median bacterial counts were lower with stabilized hypochlorous acid compared with control and were further reduced after irrigation and treatment of both groups on day 4, but remained lower in the stabilized hypochlorous acid group compared with the control group. This study demonstrates immediate and durable antimicrobial action and a beneficial effect on acute wound healing after irrigation and treatment with a stabilized hypochlorous acid formulation.

There have been many studies evaluating the beneficial effects of HOCL solution on wound healing; however, there is limited data reviewing the effect of HOCL scar gel. However, the scar gel has demonstrated benefits over silicone gel treatment. In a randomized, double-blind study including 44 adults with a linear or widespread HTS or keloid scars, comparing HOCL scar gel to treatment with silicone gel, favorable results for HOCL gel were demonstrated.