Treatment of tissue with hypochlorus acid

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Treatment of infected tissues with hypochlorous acid

USPTO Application #: 20080160612

Title: Treatment of infected tissues with hypochlorous acid

Abstract: Super-oxidized water based on hypochlorous acid, such as is obtained

by the electrochemical treatment of a saline solution, may be used in the

treatment of leg ulcers or other open wounds. Preferably, the pH of the

super-oxidized water is in a range of 4 to 7, and the water has a redox

potential of >950 mV. Medicaments based on the super-oxidized water may be in

liquid or gel form. The super-oxidized water is able to control the microbial

population within the wound and at the same time permit cell proliferation. (end

of abstract)

Agent: Cooley Godward Kronish LLP Attn: Patent Group - Washington, DC, US

Inventor: Joe B. SELKON

USPTO Applicaton #: 20080160612 - Class: 435375 (USPTO)

Treatment of infected tissues with hypochlorous acid description/claims

The Patent Description & Claims data below is from USPTO Patent Application

20080160612, Treatment of infected tissues with hypochlorous acid.

Brief Patent Description - Full Patent Description - Patent Application Claims

monitor keywords CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/844,826, which is

a continuation of application Ser. No. 10/830,878, now U.S. Pat. No. 7,276,255,

which is a divisional of application Ser. No. 10/084,518, now abandoned, which

is a continuation of PCT/GB00/03264, which was published in the English language

on Mar. 1, 2001 under International Publication No. WO 01/13926 A2, and the

disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to mixtures of oxidants which are referred to in this

specification as " super-oxidized water, " a term which is known in the art.

Super-oxidized water may be used as a sterilizing, disinfecting and biocidal

solution. One form of super-oxidized water is produced by the applicant under

the trademark STERILOX®. This STERILOX super-oxidized water is generated at the

point of use, for example in a hospital, by passing saline solution over coated

titanium electrodes separated by a semi-permeable ceramic membrane at a current

of about 6 to 9 Amps. An apparatus having coated titanium electrodes separated

by a semi-permeable ceramic membrane is disclosed in the specifications of UK

Patent Nos. 2253860 and 2274113. The basic structure of the apparatus is

disclosed in GB2253860 and can be used to produce the STERILOX super-oxidized

water.

STERILOX super-oxidized water contains a mixture of oxidizing species,

predominantly hypochlorous acid (HOCl) and sodium hypochlorite. The STERILOX

super-oxidized water has a pH of 5-7 and an oxidation reduction potential

(redox) of around 1000 mV. The high redox potential allows for the quick and

efficient destruction of microbes (bacteria, viruses, fungi and spores).

Hypochlorous acid and hypochlorite are in equilibrium and the position of the

equilibrium is determined solely by the pH.

Applicant has found that the resultant super-oxidized water is non-hazardous,

non-irritating and non-sensitizing to the skin, non-irritating to the eyes, not

harmful if swallowed and shows no evidence of mutagenic activity.

It is considered that hypochlorous acid exerts its biocidal effect by attacking

the surface and plasma membrane proteins, impairing transport of solutes and the

salt balance of bacterial cells (Pieterson et al, Water SA, 22(1): 43-48

(1996)). However, it is believed that HOCl does not enter freely into eukaryotic

cells, which may explain the selectivity of hypochlorous solutions.

The STERILOX process produces an extremely effective sterilizing, cold,

non-toxic solution, which is free from highly toxic chemicals and acts against a

wide variety of bacteria, fungi, viruses and spores. The generation of STERILOX

solutions requires only water, electricity and pure, vacuum-dried crystalline

salt. Applicant considers that the STERILOX super-oxidized water will be

suitable for a broad range of applications in both medical and non-medical

environments, such as the preservation of poultry and fish and general

agricultural and petrochemical uses, the breaking down of bacterial biofilm,

water treatment and general disinfection in medical and veterinary applications.

The STERILOX super-oxidized water has been found to be particularly useful for

the disinfection of endoscopes which are sensitive to other cold disinfectants,

such as peracetic acid, which are commonly used.

While glutaraldehyde may be used as a reliable disinfecting agent of flexible

fiber-optic endoscopes and other heat-sensitive instruments, although being

widely practiced in many hospitals, its use can cause asthma and dermatitis in

healthcare staff as a result of exposure to glutaraldehyde fumes, hence a

predilection to the use of peracetic acid and the relatively recent move towards

the use of STERILOX super-oxidized water in such applications.

STERILOX super-oxidized water has been tested and is the subject of two

scientific papers by Selkon et al, Journal of Hospital Infection, 41: 59-70

(1999) and Shetty et al, Journal of Hospital Infection, 41: 101-105 (1999). In

these studies, freshly produced STERILOX super-oxidized water was found to be

highly active against Mycobacterium tuberculosis, Mycobacterium

avium-intracellulare, Mycobacterium chelonae, Escherichia coli (including type

0157), Enterococcus faecalis, Pseudomonas aeruginosa, Bacillus subtilis var

niger spores, methicillin-resistant Staphylococcus aureus, Candida albicans,

poliovirus type 2 and human immunodeficiency virus HIV-1.

There has been a recent upsurge in interest in the use of super-oxidized water

as a disinfectant, because of its rapid and highly biocidal activity against a

wide range of bacteria. Tanaka et al, Journal of Hospital Infection. 34: 43-49

(1996), report the electrolysis of a saline solution to produce a super-oxidized

water with a highly acidic pH of 2.3-2.7, which limits its suitability for many

applications, particularly the disinfection of endoscopes. The acidic pH of the

super-oxidized water produced by the method described by Tanaka et al. also

precludes its use in other medical indications.

Having carried out trials in a large number of applications, including those

mentioned above, Applicant turned its attention to the use of STERILOX

super-oxidized water as a disinfectant of mammalian tissue, in particular the

treatment of open wounds such as leg ulcers.

An article by Chemy in The Prescriber (May 1996) entitled " GP guide to the care

of patients with leg ulcers " states " leg ulcers are notoriously difficult to

treat successfully and can seriously reduce the patient's quality of life. "

Indeed, according to Chemy, " epidemiological studies have shown that at any

given time there are approximately 100,000 patients in the UK that have leg

ulceration. In treating these patients it has been estimated that over £39

million per year alone is spent on materials used in their ulcer care. "

There are two types of leg ulcers: arterial and venous. Arterial ulcers, which

are much harder to treat, are caused by ischemia, while venous ulcers are caused

by blood stasis in the veins.

There are many proposals for the management of ulcers, all of which have varying

degrees of success. Successful ulcer management is very much dependent on the

rigid adherence to a program of treatment in combination with effective

disinfection of the wound, which reduces bacterial infection and promotes the

regeneration of dermal fibroblasts and keratinocytes in the bed of the ulcer

which are essential for healing of the wound and the growth of new tissue. If

the bacterial growth is not controlled, the wound cannot heal.

The most useful treatment for venous ulcers is the use of compression bandages

together with elevation of the leg(s). This mimics the pumping action of the

calf muscles which return the blood back to the body and maximizes the removal

of blood from the leg(s). In conjunction with this, other treatment strategies

include the use of topical treatments such as GRANUFLEX® to aid granulation and

skin repair, alginates to clean the wound of debris, dry inert dressings to

protect the wound (but which do not promote healing), and bacteriostatic or

bactericidal ointments to reduce the infection. While antibiotics have been used

to reduce infection in the past, nowadays this is not a treatment of choice due

to the increased risk of antibiotic resistance.

While potassium permanganate (KMnO4) is an oxidant which has stood the test of

time in the treatment of leg ulcers, it still nevertheless has the disadvantages

of irritating and injuring newly grown skin and causing skin discoloration.

Known hypochlorites, such as EUSOL (Edinburgh University Solution of Lime) and

Daikin's solution, rely on a high concentration of hypochlorite ions for their

disinfectant properties. In fact, these compounds are no longer recommended for

use due to their irritant and painful effects and impairment of cell growth

which outweigh their therapeutic value, resulting in these preparations falling

out of use. Attempts have been made to reduce the alkaline effect of the high

hypochlorite ion content of these Solutions, e.g. by the use of suitable

buffers, but have been found to be ineffective in such circumstances.

All this has militated against the use of preparations including hypochlorites

for the treatment of leg ulcers. However, the success in disinfection and

sterilization of endoscopes and the known non-irritant effects of the STERILOX

super-oxidized water, have led the Applicant to re-address the treatment of open

wounds such as leg ulcers.

BRIEF SUMMARY OF THE INVENTION

As a first step, in vitro tests were carried out on single layers of cultured

human dermal fibroblast cells and keratinocyte cells to ascertain whether or not

super-oxidized water had any effect on the viability of the cells. The cells

were incubated under sterile conditions in a super-oxidized water based on

hypochlorous acid and including sodium hypochlorite and other oxidized chlorine

species, having a pH range from 4 to 7 and a redox potential of around 1000 mV.

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