|A Potent and Safe Wound Care Agent|
|By Ron Najafi, PhD|
|Tuesday, 13 December 2011 07:45|
Chronic wounds can become infected by Staphylococcus including MRSA, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia, and Serratia spp. that can form a biofilm that can become a major obstacle for wound closure and the healing process. If the physician cannot control the infection in these chronic wounds, the patient may become further compromised by additional tissue damage, bacteremia, sepsis or deeper wound infections.
Attempts to control the bioburden of these chronic non-healing wounds have been very difficult. Systemically administered antibiotics do not effectively decrease the level of bacteria or the associated biofilm in a chronic granulating wound. Topical antiseptics have been the method of choice but still do not fully provide effective alternatives or significant improvement.
Topical antiseptics have a long history of use, such as sodium hypochlorite (Dakin’s solution), hydrogen peroxide, acetic acid and povidone-iodine that remain in widespread use today. Used at typical concentrations, these disinfectants can actually impede wound healing and are discouraged for use on chronic ulcers. Therefore, the standard of care for chronic ulcers is debridement and moisture retentive dressings.
A Pure Form of Hypochlorous Acid
Hypochlorous acid (HOCl) is a very potent broad-spectrum antimicrobial agent produced by the body’s white blood cells as part of the innate defense against microbial pathogens through phagocytosis and oxidative burst with no to low potential for resistance. In the past, companies and compounding pharmacies have attempted to prepare various forms of pure HOCl unsuccessfully and have unfortunately had to settle with mixtures such as Dakin’s solution which is a mixture of sodium hypochlorite (bleach) and HOCl (innate immune molecule).
Pure HOCl in solution has been described as being 80-100 times more potent as a germicide than the hypochlorite anion (high pH). This is because pure HOCl in solution as a neutral/uncharged species can penetrate microbial cells and spore walls while the charged hypochlorite anion cannot penetrate cell walls. Pure HOCl is protonated and neutral in solution at acidic pH’s.
An understanding of chlorine chemistry is important in order to appreciate both the active form and the long-term stability in glass or plastic containers. Chlorine species in aqueous solution transforms into two active forms: hypochlorous acid (HOCl) and the hypochlorite anion (OCl-). The pH range where the ratio of the two species (HOCl/OCl-) in 0.9% saline gives pure HOCl (i.e. >97% relative molar distribution of active chlorine species as HOCl) is at pH 4-6. One finds mixtures of hypochlorous acid and hypochlorite anion at neutral (pH 7) and hypochlorite anion at basic pH ranges (pH >8).
Recent in vitro research studies showed that hypochlorous acid was effective against both planktonic and biofilm forms of S. aureus; the researchers concluded that the compound was equally effective in vitro against various antibiotic-sensitive and resistant S. aureus isolates when tested in minimum bactericidal concentration and time kill assays.
NeutroPhase® has recently garnered much attention within the wound care research community due to a series of studies indicating that it is a safe, effective, broad-spectrum antimicrobial agent against: Gram-positive bacteria including MRSA, VRE, and Bacillus anthraxis, Gram-negative bacteria; yeast; fungi; and Acanthamoeba. NovaBay has conducted several GLP studies indicating broad safety profile of NeutroPhase®.
NeutroPhase® is pure 0.01% hypochlorous acid (i.e. >97% relative molar distribution of active chlorine species as HOCl) in a 0.9% saline solution at pH 4-5 and NovaBay has an FDA cleared 510(k) for wound cleansing, irrigation and to aid in wound debridement.
Clinical Case Studies with NeutroPhase®
Clinical case studies using NeutroPhase® shown that we can use a variety of wound mesh dressings, with (or without) negative pressure wound therapy (NPWT). Wound mesh dressings are designed to aid in the reduction of tissue maceration of the adjacent skin next to the wound. Clinical case studies have shown a marked increased speed of wound healing without being toxic to living tissues.
John Crew, M.D., Vascular Surgeon at the Wound Care Center, Seton Medical Center, has used NeutroPhase® with a variety of wound mesh dressing, with (and without) NPWT in many severe chronic non-healing wounds showing good wound closure and accelerated wound healing.
NeutroPhase® was used with a simplified and streamlined NPWT clinical protocol that involves moistening the wound with a moist compress wetting with NeutroPhase® on standard cotton gauze prior to physical cleaning, debridement and drying of the affected wounds. Thin film dressings were used to cover the wound and hold a hydrophobic mesh in the wound, a pre-cut silicone tube (instillation port) positioned at the wound bed, and a Trac-Pad (exit port) in place for negative pressure wound therapy (NPWT). The wound area was then wrapped in cotton gauze and a secondary dressing as ordered by the physician. Wound care specialists or informed patients can instill NeutroPhase® with NPWT as instructed by the attending surgeon or wound care nurse.
The results were that by the use of NeutroPhase® and NPWT in many severe chronic non-healing wounds (e.g. below-the-knee amputation, chronic venous girdle ankle ulcer, cancer patient with a radical excision of a squamous cell cancer exposing cranial bone) resulted in marked accelerated wound repair in patients.
NeutroPhase® will be launched in 2012 in a glass 40 mL bottle with an optional finger actuated spray pump for wound care. There is a clear potential for the use of NeutroPhase® as a key agent in wound healing for a wide variety of wound types.
About the Author
Ron Najafi, PhD is the founder and Chairman of NovaBay Pharmaceuticals. He has served as President since July 2002, and as Chief Executive Officer since November 2004. Previously, Dr. Najafi served in various management positions within NovaBay including as Chief Scientific Officer. Prior to founding NovaBay, Dr. Najafi was the President and CEO of California Pacific Labs, Inc., a chemical laboratory safety devices company. He has also held scientific roles at RhônePoulenc Rorer (now Sanofi-Aventis), Applied Biosystems, a division of PerkinElmer, Inc., and Aldrich Chemical. Dr. Najafi received a B.S. and M.S. degree in Chemistry from the University of San Francisco and a Ph.D. in Organic Chemistry from the University of California at Davis. Contact him at NovaBay Pharmaceuticals, Inc., 5980 Horton Street, Suite 550, Emeryville, CA 94608. Phone: (510) 899-8800. Fax: (510) 225-0371.