WO2017210454A1

WO2017210454A1 - Ophthalmic disinfecting agent and methods of using the same

Info

Publication number: WO2017210454A1
Application number: PCT/US2017/035493
Authority: WO
Inventors: Jonathan Mark PETRASH; Robert W. ENZENAUER; Niklaus H. MUELLER; David A. AMMAR; Michelle PEDLER
Original assignee: The Regents Of The University Of Colorado, A Body Corporate
Priority date: 2016-06-03
Filing date: 2017-06-01
Publication date: 2017-12-07

Abstract

Ophthalmic preparations comprising an oxidizing antimicrobial agent such as chlorine dioxide with improved antibacterial effects. The invention has particular use as an eye care preparation such as an eye drop for disinfecting the eye and for preventing or treating ocular infection.

Description

OPHTHALMIC DISINFECTING AGENT AND METHODS OF USING THE SAME

FIELD OF THE INVENTION

The invention relates to methods of disinfecting an eye by application of a chlorine dioxide formulation.

BACKGROUND

Ocular injuries, such as corneal trauma and penetration of the eye, may result in blindness if such injuries are not treated quickly. Disruption of the corneal surface damages the innate immune barriers of the eye and allows for infiltration and

colonization of the injured areas by opportunistic pathogens. Colonization of the damaged eye, if untreated, results in greater damage to the eye. Thus, early intervention to prevent infections associated with ocular damage is important for better visual outcomes, and methods of treating ocular infection at the site of injury are therefore necessary to limit or prevent irreversible ophthalmic damage.

Like other human flora, Candida albicans, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli cause infections of many tissues, including the eye. Antibiotics are currently used to treat such microbial infections in order to minimize damage to vision. The increase in antibiotic resistance rate of such bacteria, however, has created a need for new antiseptics that are safe and effective for use in the eye.

The current standard of care for ocular disinfection in clinica l practice is irrigation of the ocular surface with povidone-iodine (Betadine™). This form of elemental iodine is commonly used to prevent accidental or opportunistic infections by pathogens that may be present on the ocular surface prior to injections for other invasive surgical procedures performed on the eye, for example in the treatment of age-related macular degeneration (AMD) and diabetic retinopathy. Such disinfecting pretreatment is necessary to prevent patients from developing vision loss due to ocular infection. But many patients experience such severe pain from iodine disinfection that they avoid clinical treatments. Thus, the use of disinfecting iodine preparations, including povidone-iodine, is dose- limiting, and even therapy-limiting, in the ongoing treatment of some eye disorders. Many other procedures, including wound repair, also require disinfection of the ocular surface. Patients would therefore benefit from an improved disinfecting agent that causes limited or no ophthalmic pain.

Lastly, mustard agents used in chemical warfare cause severe damage to the eyes. Mustard agents act via alkylation of various biological targets, and their greatest toxicity results through nonspecific alkylation of DNA. On-site application of an agent that can chemically inactivate alkylating agents would greatly reduce the damaging effects of such chemical warfare agents. There are currently no effective and specific antidotes for ocular exposure to mustard agents, nor are there any effective decontamination methods available that are not toxic to the eye. Thus, there is an additional need for ophthalmic formulations that effectively prevent or ameliorate the ocular damage caused by mustard agents used in chemical warfare.

SUMMARY

The instant invention is based on the discovery that ophthalmic formulations comprising an oxidizing antimicrobial agent such as chlorine dioxide exhibit beneficial effects as topical disinfectants and are therefore useful in the prevention of ocular infection caused by trauma or penetrating procedures.

Accordingly, in at least one aspect, this disclosure provides eye care formulations comprising chlorine dioxide that have antimicrobial activity. These ophthalmic

formulations may have additional active or inactive ingredients that enhance the antibacterial effects of the chlorine dioxide, or act synergistically with the chlorine dioxide, or act to stabilize the chlorine dioxide in the formulation, or act to prolong the antibacterial effect of the chlorine dioxide following application of the formulation to the eye.

The chlorine dioxide in the formulations may be present in a concentration of about 25-125 ppm, or about 50-75 ppm, or about 60 ppm.

The formulations of the invention include solutions, creams, pastes, ointments, and gels. The formulations may be, for example, topical formulations that are applied to the eye, eye-lid, or margins surrounding the eye. Further, the formulations are effective against bacteria, fungi, and/or yeast. The formulations are also effective in

decontamination of mustard gas warfare agents in the prevention of ocular damage following exposure to such agents. These formulations may further comprise a pharmaceutically acceptable carrier. In exemplary embodiments, the formulation is a solution. The solutions may have an osmolality of 180 mOsm/Kg or less, or 165 mOsm/Kg or less.

An exemplary formulation is an eye care formulation having an osmolality of 165 mOsm/Kg or less and a chlorine dioxide concentration of about 50-75 ppm.

In an unexpected finding, these formulations do not provoke avoidance behavior (as a surrogate of pain avoidance) when used to disinfect ocular surfaces, as is common with many antimicrobial treatments for the eyes (e.g., Betadine™ treatment of the eye).

This disclosure also provides methods of using these formulations. The methods include, for example, a method of preventing or treating microbial infection in an eye of a subject by applying the formulations of this disclosure to an infected area in or around an eye in an amount sufficient to prevent or treat a microbial infection in the subject. In these methods, the microbial infections may include bacterial, fungal and yeast infections.

These methods also include, a method of preventing, or ameliorating, or treating ocular damage in a subject following exposure of the subject to mustard gas by applying the formulations of this disclosure to an exposed area in or around an eye in an amount sufficient to prevent or treat ocular damage in the subject.

These methods also include, methods of preventing an infection of the ocular surface in a subject undergoing an ocular injection for therapy of an eye disorder by applying the formulation to an ocular surface in an amount sufficient to prevent an opportunistic or accidental infection of the ocular surface in the subject during the ocular injection.

These methods also include, methods of preventing an infection of the ocular surface in a subject undergoing a surgical procedure on an eye by applying the formulation to an ocular surface in an amount sufficient to prevent an opportunistic or accidental infection of the ocular surface in the subject during the surgical procedure.

The invention also provides methods of reducing the risk of infection of the eye in an eye surgery patient by applying the formulations described herein to an eyelid or ocular surface prior to a surgical procedure in an amount sufficient to reduce the risk of infection in the eye of a surgical patient.

I n these methods, the formulations of this disclosure may be applied multiple times over a number of days preceding the surgery or injection.

This disclosure also provides methods for treating or reducing the risk of infection in a subject by applying the topical formulations of this disclosure to the area that is infected or at risk of becoming infected in an amount sufficient to treat or reduce the risk of infection.

This disclosure also provides kits for the treatment or prevention of an ocular infection, comprising a formulation of this disclosure and instruction for use. The invention also provides kits for the treatment of an ocular disorder comprising an antimicrobial formulation of this disclosure and instruction for use. These kits may further comprise an applicator.

BRIEF DESCRIPTION OF THE DRAWINGS

The following Detailed Description may be understood in conjunction with the accompanying figures in which :

Figure 1 shows a scratched cornea of a Sprague-Dawley rat, demonstrating disruption of host immune defenses to mimic ocular trauma. An 18-gauge needle was passed over the cornea to disrupt host immune defenses to mimic ocular trauma. Tissue sections in the image were gram stained.

Figure 2 shows the differences in bacterial load measured through colony forming units (CFU) of S. aureus after allowing overnight growth of S. aureus on infected rat eyes treated with either eLectrol (eB) or a PBS control. Each eye had a corneal wound

(scratched with an 18G needle) and inoculated with 10⁷ CFU of S. aureus for 15 minutes and then lavaged with 50 μί of eB or PBS. The eyes were then swabbed, cultured in LB for 1 hour and serial dilutions were performed on MSA overnight to determine CFU .

Statistics by unpaired t test with Welch's correction where *P<0.05.

Figure 3 shows the inactivation of an alkylating agent by treating the

chemotherapy agent streptozotocin (STZ) with eLectrol (eL). Various amounts of streptozotocin (0-3 μιηο^) was pre-treated with 1 ml of eL or buffer (a formulation lacking the active ingredient). The mixtures were then reacted with 200 μιηο^ of 4-(4- Nitrobenzyl) pyridine (NBP). Absorbance of the purple adduct was measured at 540 nm.

Figure 4 shows the difference in rat behavior when administered eye drops containing eLectrol (eB) versus those containing Betadine™. Eyes were treated with eB or betadine and the number of behaviors exhibited, including wipes, blinks and avoidance behaviors, were each given a score of one and totaled to give a score for behavior.

Figure 5A shows an H&E 20X magnification of a whole eye of a rat treated with eLectrol for 6 hours.

Figure 5B shows a Caspase 3 stain of an eLectrol treated eye.

Figure 5C shows a 20X magnification of Jurkat cells treated with 5μΜ

camptothecin for 24 hours and stained with caspase 3 positive control.

DETAILED DESCRIPTION

There exists a need for compositions and methods for preventing microbial growth and treating microbial infections of the eye or surrounding areas. Preferably, these compositions and methods would prolong the contact of the eye with compounds that inhibit microbial growth and that do not irritate the area to which it is applied.

Preferably, these compositions contain an antimicrobial composition that will kill or retard the growth of microbes (e.g., a bactericidal or bacteriostatic composition).

Definitions

The term "cleaning" is used herein to describe the act of significantly reducing the amount of dirt, debris, or bacteria, from a surface, such as the surface of the eye, an eyelid, and/or the margins of an eye.

The term "eyelid" as used herein, includes the tarsal conjunctival surface, both the interior and exterior surfaces of the eyelid, the eyelid margin, the glands in and around the eyelid margins, the hair follicles of the eyelid, the eyelashes, and the periocular skin surrounding the eye.

Animal models for eye injury and eye injection as well as eye disorders have been produced, and can be used to test the efficacy of the formulations of this disclosure. These models may include, for example, rabbits or mice and the use of such models is described further in the Examples section of this disclosure. The term "ocular disorder" as used herein, includes ocular surface disorders, disorders of the eyeball, periocular skin disorders, and eyelid disorders. Exemplary ocular disorders include, but are not limited to, dysfunctions of the tear film, inflammation of the eyelid margins due to bacterial infection, infections inside the eye known as endophthalmitis, and dry eye.

The term "treatment" as used herein is defined as prophylactic treatment (e.g., daily preventative use) or therapeutic treatment (e.g., a single treatment or a course of treatment) of a subject with or at risk for an ocular disorder, or with an ear or skin condition, that are associated with or exacerbated by infections or bacterial colonization.

The term "formulation or antimicrobial formulation" as used herein includes compositions comprising an oxidizing antimicrobial compound, for example, chlorine dioxide. The formulations of this disclosure can be a solution, cream, paste, ointment, gel or the like. The formulations of this disclosure can be applied to, for example, the skin, eye, or eyelid.

As used herein "pharmaceutically acceptable carrier" is intended to include any and all solvents, agents, and the like, compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the antimicrobial formulations described herein, such media can be used in the formulations of this disclosure. Pharmaceutical compositions suitable for topical application preferably take the form of a drop, solution, ointment, cream, lotion, paste, gel, spray, aerosol, or oil. Exemplary carriers which may be used include water, carboxymethylcellulose, petroleum jelly, mineral oil, lanolin, polyethylene glycols, alcohols, and combinations of two or more thereof.

Methods and Compositions

Effective health and cleanliness of an eye is dependent upon the ability to control the level of microbes. Accordingly, compositions that can extend the contact of the oxidizing antimicrobial compound with the eye may be useful in controlling the level of microbes in and around the eye and prevent or better treat infections of the eye.

The present disclosure provides compositions and methods, which decrease, e.g., significantly decrease, the number of microbes present in or around an eye. Accordingly, this disclosure provides a formulation comprising an antibacterial concentration of chlorine dioxide in a formulation that improves (i.e., increases) the residence time of the chlorine dioxide on the ocular surface, thereby improving the antibacterial effect of the chlorine dioxide formulation. The formulation may also contain a pharmaceutically acceptable carrier or water. The formulation may be used as a preservative for materials used in conjunction with the eye such as eye drops or may be specifically formulated for the treatment of a particular disorder, e.g., an ocular disorder selected from blepharitis, dry eye, infectious conjunctivitis, an ear infection, or a skin infection. The formulations of this disclosure may be prepared in the form of drops, solution, paste, cream, foam, gel, ointment, or the like, or incorporated into sustained-release carriers such as sustained- release polymers, liposomes and microcapsules.

There are several commercial generators for producing the chlorite/chlorine, chlorine dioxide, for example, those disclosed in U.S. Pat. Nos. 4,247,531; 5,204,081; 6,468,479; and 6,645,457, the disclosures of which are incorporated herein by reference.

Chlorine dioxide can be produced with high efficiency by reducing sodium chlorate in a strong acid solution with a suitable reducing agent (for example, hydrogen peroxide, sulfur dioxide, or hydrochloric acid):

2CIO3 ^"+2C|-+4H⁺ ^ 2CI0₂+CI₂+2H₂0

Alternatively, chlorine dioxide can be made by one of three methods using sodium chlorite: The sodium chlorite— chlorine gas method (2 NaCI0₂ + Cl₂ -> 2 CI0₂ + 2NaCI) or the sodium chlorite- hypochlorite method (2NaCI0₂ + 2HCI + NaOCI -> 2CI0₂+ 3NaCI + H₂0). Finally, chlorine dioxide can be produced by electrolysis of a chlorite solution (NaCIOz + H₂0 CI0₂ + NaOH + 1/2 H₂).

Chlorine Dioxide solutions suitable for uses in the current application may also be obtained commercially from Strategic Resource Optimization, Inc. as "eLectrol" which maintains the disinfectant properties chlorine dioxide, while employing a formulation that enhances adherence to the ocular surface.

Formulations of this disclosure may comprise between about 25-200 ppm of chlorine dioxide, about 50-150 ppm of chlorine dioxide, about 50-100 ppm of chlorine dioxide, or about 50-75 ppm of chlorine dioxide. For treatment of infection, higher values may be used. These antimicrobial formulations may comprise an aqueous solution containing chlorine dioxide that may have an osmolality of, for example, about 180 mOsm/Kg, about 175 mOsm/Kg or less, about 170 mOsm/Kg, about 165 mOsm/Kg or less, about 160 mOsm/Kg or less, or about 155 mOsm/Kg or less. An exemplary formulation of this disclosure is a formulation having an osmolality of 165 mOsm/Kg or less and a chlorine dioxide concentration of about 50-75 ppm.

These formulations may further include buffers, solubilizers, viscosity increasing agents, preservatives, anti-inflammatory agents and salts.

A preferred formulation of this disclosure provides an eye drop comprising chlorine dioxide and a balance of electrolytes and/or buffers found in natural tear fluid required for ocular surface maintenance, function and repair. These electrolytes and/or buffers may be present in amounts and proportions sufficient to maintain or restore the health of cells of the eye or surrounding tissues. The inclusion of such electrolytes and/or buffers in these formulations enables topical application of these formulation to ocular surfaces, preferably without substantially reducing the buffering capacity of the naturally-occurring solutions/suspensions of the eye. The inclusion of such electrolytes and/or buffers in these formulations may also help to minimize or even eliminate irritation of the eye by the active agents present in these formulations.

The eye drop compositions of this disclosure may include, in addition to chlorine dioxide, a balance of electrolytes naturally found in tear fluid. These electrolytes principally include major amounts of sodium and chloride, and lesser amounts of potassium and bicarbonate.

These formulations may also contain other naturally-occurring elements of the tear fluid, such as proteins, enzymes, lipids and metabolites as described in U.S. Pat. No. 4,911,933. Typically, in an isotonic formulation, the potassium is present at a

concentration of about 22.0 to 43.0 mM, the bicarbonate is present at a concentration of about 29.0 to 50.0 mM, the sodium is present at a concentration of about 130.0 to 140.0 mM, and the chloride is present at a concentration of about 118.0 to 136.5 mM, or the electrolyte components can be diluted to create hypotonic formulations where the ratios between the electrolyte concentrations remain unchanged. The eye drop formulations of this disclosure may further optionally include calcium, magnesium and phosphate. In such embodiments, in isotonic formulations, the calcium is preferably present at a concentration of about 0.5 to 2.0 mM, the magnesium is preferably present at a concentration of about 0.3 to 1.1 mM, and the phosphate is preferably present at a concentration of about 0.8 to 2.2 mM. For hypotonic

formulations, the electrolyte components can be diluted to create hypotonic

formulations where the ratios between the electrolyte concentrations remain unchanged.

The pH of these ophthalmic formulations generally ranges from about 7.0 to 8.0. However, this pH range need not be rigidly adhered to, and it may be desirable to alter pH outside of this range, for instance, to improve the antimicrobial effect on the ocular surface.

The formulations of this disclosure can be applied to the ocular surface by various methods known in the art. For example, these formulations can be applied topically to the ocular surface as eye drops or ointments. The formulation can also be applied using an eye cup so that the eye is bathed. The formulation can also be applied using a continuous or near continuous infusion device for ocular surface irrigation and/or wetting and/or drug delivery. The formulation can also be applied by release from a sustained-release carrier such as a sustained-release polymer, a liposome or a microcapsule. The formulation may also be applied by devices that spray solutions as required onto the surface of the eye.

This disclosure is further directed to methods of using the formulations described above to treat a subject, e.g., a subject having or at risk of having an infection, e.g., an infection of the eye or skin. The method comprises the step of applying an antimicrobial formulation as described above to the site of the infection, or site where an infection is likely to occur, or the site from which an infection might originate, for a time and under conditions effective for reducing the amount of a microbe (e.g., bacteria) present. In a specific embodiment, the time and conditions selected result in an at least about 1 log reduction in colony-forming units of the infecting bacteria after one minute of exposure to the antimicrobial formulation. In other embodiments, the application of the antimicrobial formulation for one minute results in an at least about 2, 3, 4 or 5 log reduction in colony-forming units.

This disclosure also provides methods of treating ocular infections that may result from, or are complicated by bacterial colonization or infection of the eye or surrounding tissue caused by trauma or penetrating procedures (e.g., injections into the eye or surgical procedures on the eye), by applying the formulations provided herein to the eye and/or surrounding tissue of a subject.

This disclosure also provides methods of preventing an eye infection in a subject having an eye surgery or procedure. These methods would comprise applying the antimicrobial formulations of this disclosure to the eye over a number of days preceding the surgery or procedure to reduce or eliminate the risk of developing an infection during the surgery or procedure. Exemplary procedures include injections into the eye, i.e., for peri-operative ocular disinfection for patients who require ocular injections for treatment of chronic conditions, including, but not limited to, diabetic retinopathy, uveitis, or macular degeneration, or cataract or LASIK surgery.

This disclosure also provides methods of treating or preventing an eye disorder or injury in a subject that has been exposed to or may be at risk of exposure to chemical warfare agents, such as a mustard gas.

Application of the antimicrobial formulations set forth herein can be by any one of a number of art recognized methods. For example, application can be made by an applicator, such as a Qtip or pad, by drops from a dropper or bottle.

The antimicrobial formulations of this disclosure may be applied one or more times per day, and may be left in place as long as needed, depending on the intended indication. The number of days which a subject applies the antimicrobial formulation, and the duration of the application, will depend on the intent of treatment or on the location and severity infection, and efficacy of the formulations on a given infection. In certain embodiments, the antimicrobial formulation may be applied for a period of 30 seconds, 45 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, or longer.

The antimicrobial formulation can be applied by release from a sustained release carrier such as a sustained-release polymer, a liposome or a microcapsule. The ordinary skilled clinician would be able to effectively prescribe a treatment regimen that will be effective in treating or preventing an infection in an individual.

The methods described above may further include a rinsing step after a recommended period of exposure. This step preferably comprises a simple water rinse. The antimicrobial formulation may be rinsed from the area to which it was applied with ample water after application, e.g., with a hand, finger or any moist pad or cloth suitable for this purpose.

Commercial Applications

The methods and compositions of this disclosure find numerous commercial applications that could beneficially utilize compliance enhanci ng methods and compositions for antibacterial a pplications. Consequently, this disclosure includes a kit comprising the formulations of this disclosure, e.g., a kit for the treatment of an infection, e.g., an ocular infection, an ocular disorder, eye injury. The kits optionally include an applicator. The formulation can be in the form of drops, solution, paste, cream, foam, gel, or ointment, or the like, when included in the kits of this disclosure.

The kit may optionally be packaged with instructions for use. The kit may optionally contain a dispenser or applicator, e.g., a sponge, to apply the antimicrobial formulations of this disclosure to the infected area of a subject.

EXAMPLES

Example 1: chlorine dioxide is efficacious against bacterial infection in a cornea scarification model

Ocular injuries are associated with corneal trauma with possible penetration of the eye, and if not treated quickly may result in blindness. Disruption of the corneal surface damages the innate immune barriers of the eye that allows for infiltration and colonization of the injured areas by opportunistic pathogens. Colonization of the damaged eye if untreated will result in greater damage to the eye. Current treatments that potentially minimize the da mage to vision include administering antibiotics both systemically and at the site of injury. Early intervention to prevent infections associated with ocular damage is important for better visual outcomes.

The need for new options to treat ocular infections led us to study additional compounds that inhibit bacterial replication while protecting tissues within the eye. There are a number of compounds used as disinfectants that have known antimicrobial properties but are cytotoxic. Dilution of some disinfectants allows for their use on tissues as antiseptics. The disinfectant Electro-BioCide™ is a broad-spectrum antimicrobial that works by a different, less characterized, mechanism of action. Environmental Protection Agency has classified Electro-Biocide a category IV ("practically non-toxic") agent making it potentially useful for treatment of ocular infections.

A modified form of Electro-BioCide™, "eLectrol" with tissue favorable

modifications was tested to determine the protective effects of the composition as an antimicrobial that is safe for ocular infections.

Numerous microbes can cause ocular infection, however only a few of them are normal flora that become opportunistic pathogens when trauma occurs. Like other human flora, Candida albicans, Staphylococcus aureus, Bacillus subtilis (a model organism or B. anthracis), Pseudomonas aeruginosa, and Escherichia coli are well-documented opportunistic infections of many tissues including the eye. Moreover, the increase in antibiotic resistance rate of these bacteria make them ideal targets for testing new compounds as antiseptics in the eye.

In initial studies, the inventors scratched one cornea in each of 12 rats, infected them with S. aureus, and then treated them with eLectrol. The eyes were then harvested and analyzed for bacterial loads. The corneas of three month old Sprague-Dawley rats were scratched with an 18-gauge needle to induce a corneal wound (Figure 1). Eyes were inoculated with 107 colony forming units (CFU) of S. aureus for 15 min. Eyes were then washed with either eLectrol or a phosphate buffered saline (PBS) control solution. After 15 min, the eyes were either left untreated or were treated by installation of either eLectrol formulation or PBS as control. Thereafter, animals were returned to housing and monitored twice daily for signs of inflammation and scratching and irritation of either eye. After a 4hr incubation, eyes were harvested and swabbed for bacteria that was plated out on Mannitol Salts Agar (MSA) while remaining tissues were formalin fixed. Following overnight growth of S. aureus, CFU were counted and analyzed for differences in bacterial load. There was approximately a 3-fold decrease in bacterial load in the eyes treated with the eLectrol formulation compared with the eyes treated with the PBS control (Figure 2).

Example 2: eLectrol can chemically inactivate mustard agents Mustard agents act via alkylation of various biological targets, and while they are powerful blistering agents, their greatest toxicity results through nonspecific alkylation of DNA.

Due to the chemistry surrounding the chlorine dioxide constituent of eLectrol, the inventors hypothesized that it could be used to inactivate mustard agents. To test this concept with an occupationally safe system, the inventors measured the ability of eLectrol to reduce the reactivity of a surrogate alkylating agent (the chemotherapy agent streptozotocin). As shown in Figure 3, streptozotocin (STZ) alkylates nitrobenylpyridine (NBP) to produce a reaction product that absorbs 540 nm light. However, the eLectrol formulation significantly reduced the ability of STZ to alkylate NBP.

Example 3: eLectrol is efficacious as an ocular surface sanitizing agent.

The standard of care for ocular disinfection in current clinical practice is to irrigate the ocular surface with betadine. This is commonly done to prevent accidental infections from a pathogen that might be present on the ocular surface prior to intravitreal (IVT) injections of anti-Vascular Epithelial Growth Factor (VEGF) drugs, which are a treatment for age related macular degeneration (AMD) and diabetic retinopathy. This treatment is critical to prevent patients from developing vision loss, yet many patients experience such severe pain from Betadine™ that they avoid their clinical treatment. While infection prevention is critical in the treatment of AMD patients with VEGF therapies, many other procedures including wound repair will obviously require disinfection of the ocular surface and hence would benefit from an improved agent that is free from pain. The inventors have hypothesized that if ocular exposure to chlorine dioxide causes little or no pain, this would be a great improvement to disinfection of the ocular surface before IVT injections.

The inventors' initial behavior studies were developed from a modified method for studying behavior in rats based on the wide range of previous behavioral studies especially focused on social interaction. The study included criteria such as scratching at the handler, scratching self, pawing eyes, licking, pacing, cowering, hiding, grooming others and length of walking. Videos were recorded and counted by blinded observers to confirm the findings (Figure 4). These data clearly show that the chlorine dioxide formulation (eLectrol) is less stressful to the animals than the Betadine™ eye drops.

Toxicity and safety measures: To test the possibility that eLectrol has a detrimental effect on the ocular surface, the inventors performed studies where the rats were transiently anesthetized in order to ensure efficient contact between the disinfecting agent and the ocular surface. The preliminary results of H&E, aSMA, and caspase 3 immunohistochemistry indicated there were no apoptotic cells in chlorine dioxide formulation (eLectrol) treated eyes (Figure 5).

It should be understood that the specified embodiments are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.

Claims

1. An eye care formulation comprising chlorine dioxide that has antimicrobial

activity.

2. The formulation of claim 1, wherein the formulation comprises at least one

additional active or inactive ingredient that enhances the antimicrobial effects of the chlorine dioxide.

3. The formulation of claim 1, wherein the formulation comprises at least one

additional active or inactive ingredient that acts synergistically with the chlorine dioxide.

4. The formulation of claim 1, wherein the formulation comprises at least one

additional active or inactive ingredient that acts to stabilize the chlorine dioxide in the formulation.

5. The formulation of claim 1, wherein the formulation comprises at least one

additional active or inactive ingredient that acts to prolong the antimicrobial effect of the chlorine dioxide following application of the formulation to the eye.

6. The formulation of claim 1, wherein the chlorine dioxide in the formulation is present in a concentration of about 25ppm to about 125 ppm.

7. The formulation of claim 1, wherein the chlorine dioxide in the formulation is present in a concentration of about 60 ppm.

8. The formulation of claim 1, wherein the eye care formulation is prepared as

solution, cream, paste, ointment, or a gel.

9. The formulation of claim 1, wherein the eye care formulation is effective against at least one of bacteria, fungi, and yeast.

10. The formulation of claim 1, wherein the eye care formulation effectively

decontaminates mustard gas.

11. The formulation of claim 1, further comprising a pharmaceutically acceptable carrier.

12. The formulation of claim 1, wherein the formulation is a solution that has an osmolality of about 180 mOsm/Kg or less.

13. The formulation of claim 1, wherein the formulation is a solution having an osmolality of about 165 mOsm/Kg or less, and a chlorine dioxide concentration of about 50ppm to about 75 ppm.

14. A method of preventing or treating microbial infection in an eye of a subject comprising applying an eye care formulation of any one of claims 1-13 to an infected area in or around an eye in an amount sufficient to prevent or treat a microbial infection in the subject.

15. A method of preventing an infection of an ocular surface in a subject undergoing an ocular injection for therapy of an eye disorder comprising applying an eye care formulation of any one of claims 1-13 to an ocular surface in an amount sufficient to prevent an opportunistic or accidental infection of the ocular surface in the subject during the ocular injection.

16. A method of preventing an infection of an ocular surface in a subject undergoing a surgical procedure on an eye comprising applying an eye care formulation of any one of claims 1-13 to an ocular surface in an amount sufficient to prevent an opportunistic or accidental infection of the ocular surface in the subject during the surgical procedure.

17. A method of reducing the risk of infection of the eye in an eye surgery patient comprising applying an eye care formulation of any one of claims 1-13 to an eyelid or ocular surface prior to a surgical procedure in an amount sufficient to reduce the risk of infection in the eye of a surgical patient.

18. The method of claims 14-17, wherein the infectious organism is a bacterium, fungi, or yeast.

19. A method of preventing, ameliorating, or treating ocular damage in a subject following exposure of the subject to mustard gas comprising applying an eye care formulation of any one of claims 1-13 to an exposed area in or around an eye in an amount sufficient to prevent or treat ocular damage in the subject.

20. A kit for the treatment or prevention of an ocular infection, comprising an eye care formulation of any one of claims 1-13 and instruction for use.