Patent Application
20080020064
At present, there exists a need for compositions and methods for preventing microbial growth and treating microbial infections. In particular, there exists a need for compositions for preventing microbial growth in products for use in the eye or surrounding area. In particular, the need exists for compositions that remain free of microbial growth for extended periods of time, i.e., compositions that contain a preservative that inhibit microbial growth and that do not irritate the area to which it is applied. Preferably, the compositions will contain an antimicrobial composition that will kill or retard the growth of microbes (e.g., a bactericidal or bacteriostatic composition). In certain embodiments, the compositions are also useful for treating or preventing infection of, for example, the skin. In further embodiments, the preparations of the invention are useful in treating or preventing infection on surfaces, medical devices, and medical instruments.
The invention will be described with reference to the following definitions that, for convenience, are collected here.
The term “cleaning an eyelid” is used herein to describe the act of significantly reducing the amount of dirt, debris, or bacteria, from an eyelid.
The term “dry eye” is known in the art as a condition of a subject that has a loss of water from the tear film due to either a decrease in tear production or an increase in tear film evaporation. Tear production can decrease from lacrimal gland disease, including, but not limited to, that which occurs in Sjögren's syndrome, or from anything that decreases corneal sensation. Examples of conditions that decrease corneal sensation include, but are not limited to, diabetes, long-term contact lens wear, and corneal surgery, including LASIK eye surgery. Tear film evaporation can increase from meibomian gland dysfunction, that manifests itself by stenosis or closure of the meibomian gland orifices, or in the presence of large palpebral fissure widths. Causes for large palpebral fissure width include, but are not limited to, normal biological variation and thyroid eye disease. Dry eye is often an age related disease, and may also be caused by a dietary deficiency of omega-3 essential fatty acids. Dry eye is associated with bacterial overcolonization of the eyelids.
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.
The term “eye surface inflammatory disorder,” as used herein, is intended to include disorders associated with eye surface inflammation. These disorders include dry eye, where ocular surface inflammation has been demonstrated, as well as both anterior and posterior blepharitis. In anterior blepharitis, the inflammation is centered around the eyelashes. Posterior blepharitis or meibomitis is associated with inflammation of the tarsal and bulbar conjunctiva, and complicated by hordeolums and chalazions, and leads to meibomian gland dysfunction. Both anterior and posterior blepharitis are associated with bacterial overcolonization of the eyelids.
Animal models with combined dry eye and eye surface inflammatory disorder have been produced, and can be used to test the efficacy of the antimicrobial preparations provided herein. For example, a rabbit model for meibomianitis and meibomian gland dysfunction has been developed. In this animal model, meibomian gland orifice closure results in the development of inflammation around the meibomian glands (i.e., meibomianitis), inflammation in the eyelids (blepharitis), inflammation in the conjunctiva (conjunctivitis) and in an increase in tear film osmolarity and a decrease in the levels of corneal glycogen and conjunctival mucus-containing goblet cells characteristic of dry-eye surface disease.
The term “eyelid disorder” is defined as a disorder that results in inflammation of the eyelashes and/or eyelash follicles and/or eyelid margins, or inflammation of the lipid producing glands that are located in the eyelid, including meibomianitis and anterior blepharitis. Exemplary eyelid disorders include, but are not limited those caused by bacterial infection.
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 “preparation or antimicrobial preparation” as used herein includes compositions comprising an oxidizing antimicrobial compound, for example, chlorine dioxide, and a heterocyclic compound that stabilizes the preparation. The preparation of the invention can be a solution, cream, paste, ointment, gel or the like. The preparations of the invention can be applied to, for example, the skin, eye, or eyelid.
The term “heterocyclic compound that improves the antibacterial effect of the chlorine dioxide preparation” is intended to include heterocyclic compounds that, when combined with chlorine dioxide, provide beneficial effects. For example, the heterocyclic compound may increase the half-life of the chlorine dioxide in the preparation, may provide beneficial treatment effects, may increase the efficacy of the preparation, etc. In an exemplary embodiment, the heterocyclic compound improves the bactericidal effect of chlorine dioxide in the compositions, thereby extending the time that the composition is free of microbial growth. Exemplary heterocyclic compounds are xanthenes. Specific exemplary heterocyclic compounds include caffeine, theophylline, dyphylline, theobromine, xanthine, xanthinol, methylxanthine, and aminophylline. In a preferred embodiment, the heterocyclic compound used in the preparations of the invention is dyphylline.
As used herein the language “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 preparations described herein, such media can be used in the compositions of the invention. 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.
Effective health and cleanliness of an eye is dependant upon the ability to control the level microbes. Accordingly, compositions that have extended utility once opened, i.e., that resist microbial growth, are useful for the treatment of the eye.
The present invention provides compositions and methods, which decrease, e.g., significantly decrease, the number of microbes present in or around, for example, an eye, or in materials used in or around the eye.
Accordingly, the invention is directed to a preparation comprising an antibacterial concentration of chlorine dioxide and a heterocyclic compound that improves the antibacterial effect of the chlorine dioxide preparation. The preparation may also contain a pharmaceutically acceptable carrier or water. The preparation 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 preparation may also be used to sterilize, for example, surgical instruments, medical indwelling devices, surfaces and the like. The preparation may also be incorporated into the surface of medical devices for sustained release of the preparation. One of skill in the art would understand that the preparation of the invention 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. Suitable generators are 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):
2ClO3−+2Cl−+4H+→2ClO2+Cl2+2H2O
Alternatively, chlorine dioxide can be made by one of three methods using sodium chlorite: The sodium chlorite—chlorine gas method (2 NaClO2+Cl2→2ClO2+2 NaCl); the sodium chlorite—hypochlorite method (2 NaClO2+2 HCl+NaOCl→2 ClO2+3 NaCl+H2O); or the sodium chlorite—hydrochloric acid method (5 NaClO2+4 HCl→5 NaCl+4 ClO2). Finally, chlorine dioxide can be produced by electrolysis of a chlorite solution (NaClO2+H2O→ClO2+NaOH+½ H2). Preparations of the invention 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.
The heterocyclic compound such as dyphylline can be present in 0.10-10%, 0.25-5% or about 1% to about 3%.
In certain embodiments, the antimicrobial preparation is an aqueous solution containing chlorine dioxide as described herein. The solutions of the invention can 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 preparation of the invention is a preparation having an osmolality of 165 mOsm/Kg or less and a chlorine dioxide concentration of about 50-75 ppm.
The preparations may further include buffers, solubilizers, viscosity increasing agents, preservatives, anti-inflammatory agents and salts.
In a preferred embodiment, the invention provides an eye drop comprising chlorine dioxide and a heterocyclic compounds. The eye drop includes a balance of electrolytes found in natural tear fluid required for ocular surface maintenance, function and repair. These electrolytes are present in amounts and proportions sufficient to maintain or restore conjunctival goblet cells and corneal glycogen, thereby maintaining mucus-mediated lubrication and the potential for normal healing. This enables topical application of the preparation to ocular surfaces preferably without substantially reducing the density of conjunctival mucus-containing goblet cells or levels of corneal glycogen. Goblet cells form a critical layer of the tear film, providing the eye surface with lubrication, and playing an important role in the system that traps foreign matter that may enter the eye, and promptly removes it. Corneal glycogen is the energy source for the sliding step in corneal wound healing. Their preservation is therefore important in maintaining the health of ocular surfaces.
The eye drop compositions of the invention include, in addition to chlorine dioxide and a heterocyclic compounds, e.g., dyphylline, 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.
The preparation 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 preparation, the potassium is present at a concentration of about 22.0 to 43.0 mM/l, the bicarbonate is present at a concentration of about 29.0 to 50.0 mM/l, the sodium is present at a concentration of about 130.0 to 140.0 mM/l, and the chloride is present at a concentration of about 118.0 to 136.5 mM/l, or the electrolyte components can be diluted to create hypotonic formulations where the ratios between the electrolyte concentrations remain unchanged.
The eye drop compositions can further optionally include calcium, magnesium and phosphate. In such embodiments, in isotonic preparations, the calcium is preferably present at a concentration of about 0.5 to 2.0 mM/l, the magnesium is preferably present at a concentration of about 0.3 to 1. 1 mM/l, and the phosphate is preferably present at a concentration of about 0.8 to 2.2 mM/l. For hypotonic formulations, the electrolyte components can be diluted to create hypotonic formulations where the ratios between the electrolyte concentrations remain unchanged.
Accordingly, in a particular embodiment, the invention provides an ophthalmic solution set forth in Table 2 of the Examples.
The pH of the ophthalmic preparation generally ranges from about 7.0 to 8.0, as measured by, for example, a Fisher pH Accumet Model 600. 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 ophthalmic drug penetration through the ocular surface. In view of the teachings provided herein, those skilled in the art may employ other pH ranges.
The eye care compositions of the invention can be applied to the ocular surface by various methods known in the art. For example, the preparation can be applied topically to the ocular surface as eye drops or ointments. The preparation can also be applied using an eye cup so that the eye is bathed. The preparation can also be applied using a continuous or near continuous infusion device for ocular surface irrigation and/or wetting and/or drug delivery. The preparation can also be applied by release from a sustained-release carrier such as a sustained-release polymer, a liposome or a microcapsule. The preparation may also be applied by devices that spray solutions as required onto the surface of the eye.
The invention is further directed to methods of using the compositions 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 the antimicrobial preparation described herein 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 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 preparation. In other embodiments, the application of the antimicrobial preparation for one minute results in an at least about 2, 3, 4 or 5 log reduction in colony-forming units.
The invention also provides methods of treating ocular disorders such as blepharitis, dry eye, eye inflammatory disorders, infectious conjunctivitis, and other ocular disorders that result from or are complicated by bacterial colonization or infection of the eye or surrounding tissue, by applying the preparations provided herein to the eye and/or surrounding tissue of a subject.
The invention also provides methods of treating infection of the ocular surface by applying the antimicrobial preparations provided herein to the eye of a subject. Exemplary infections that can be treated with the antimicrobial preparations provided herein include conjunctivitis, e.g., infectious conjunctivitis and corneal ulcers.
The invention also provides methods of preventing an eye infection in a subject having an eye surgery or procedure. These methods would comprise applying the antimicrobial preparation 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 cataract or LASIK surgery.
The invention also provides methods of maintaining low bacterial colony counts on punctal plugs that have been placed in patients for treatment. Exemplary punctal plugs include those manufactured by Odyssey Medical (Memphis, Tenn.), and Eagle Vision (Memphis, Tenn.).
Application of the antimicrobial preparations set forth herein can be by any one of a number of art recognized methods. For example, application can be by a applicator, such as a Qtip or pad, by drops from a dropper or bottle, or using a finger or fingers.
The antimicrobial preparations of the invention 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 preparation, and the duration of the application, will depend on the intent of treatment or on the location and severity infection, and efficacy of the preparations on a given infection. In certain embodiments, the antimicrobial preparation 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 preparation can be applied by release from a sustained release carrier such as a sustained-release polymer, a liposome or a microcapsule. The ordinary skilled physician 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 preparation 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.
In further embodiments, the invention provides disinfecting a surface. Exemplary surfaces include those on medical instruments, in medical facilities, on medical devices, and those in a home, e.g., in a kitchen or bathroom.
The methods and compositions of the invention find numerous commercial applications that could beneficially utilize compliance enhancing methods and compositions for antibacterial applications. Consequently, the invention includes a kit comprising the compositions of the invention, e.g., a kit for the treatment of an infection, e.g., an ocular infection, an ocular disorder, eyelid hygiene. The kits optionally include an applicator. The preparation can be in the form of drops, solution, paste, cream, foam, gel, or ointment, or the like, when included in the kits of the invention.
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 preparations of the invention to the infected area of a subject.
A study was conducted to evaluate the stability of three different formulations of the eye care preparations comprising chlorine dioxide. The basic formulations were prepared with either 0.005% chlorine dioxide alone, or 0.005% chlorine dioxide and 2.5% dyphylline. The study incorporated an evaluation of each formulation with and without autoclave sterilization in the manufacturing procedure.
The analysis consisted of both USP Antimicrobial Effectiveness (preservative efficacy) testing and analytical testing over a three month time frame, at three storage conditions: 5° C., 25° C./60% relative humidity (RH), and 40° C./75% RH. Analytical testing for chlorine dioxide content, pH, and osmolality was performed every two weeks for three months. The Antimicrobial Effectiveness was evaluated on a monthly basis on formulations that met the acceptance criteria for a Category 1 article at the initial Antimicrobial Effectiveness testing.
The analytical testing of the dyphylline/chlorine dioxide samples showed a pH drift upward in both the autoclaved and non-autoclaved formulations.
The initial Antimicrobial Effectiveness testing indicated that both autoclaved and non-autoclaved dyphylline/chlorine dioxide samples met the USP criteria at initial formulation. Samples of the autoclaved dyphylline/chlorine dioxide formulation were then tested after four months (all conditions) and met USP criteria for Antimicrobial Effectiveness.
In the chlorine dioxide formulations without dyphylline, the chlorine dioxide concentration showed no clear trend. The chlorine dioxide only formulation samples did not meet the acceptance criteria for the Antimicrobial Effectiveness testing during the initial testing and this portion of the study was discontinued.
During the execution of the initial study, a confirmatory study was performed to confirm the passing Antimicrobial Effectiveness results for the autoclaved dyphylline/chlorine dioxide sample. In addition to this sample, an autoclaved chlorine dioxide formulation and a formula based on example 5, U.S. Pat. No. 6,024,954 (consistent with Refresh) were prepared. All three were tested using the USP Antimicrobial Effectiveness testing, with the dyphylline/chlorine dioxide and the formulation based on example 5, U.S. Pat. No. 6,024,954 (consistent with Refresh) passing through 28 days, and the chlorine dioxide alone sample again failing at day 7.
The following variations of the formulations were prepared for this stability evaluation:
dyphylline/chlorine dioxide sample. In addition to this sample, an autoclaved chlorine dioxide formulation was prepared as well as a formula based on example 5, U.S. Pat. No. 6,024,954 (consistent with Refresh) were prepared (formulation in Table 3).
Samples of each formula were submitted for USP Antimicrobial Effectiveness testing.
Each formula was prepared in duplicate, with one formula prepared without autoclaving, and the other prepared with autoclaving.
When each formulation and initial analytical testing was completed, samples were submitted to microbiology for the initial Antimicrobial Effectiveness Testing. The challenge organisms were S. aureus, P. aeruginosa, E. coli, C. albicans, and A. niger.
The remainder of the bulk solutions was filled into low density polyethylene (LDPE) bottles and placed into the appropriate stability chambers. The autoclaved dyphylline/chlorine dioxide formulation had an additional test performed at approximately four months to correlate with the last Antimicrobial Effectiveness testing.
During the execution of the initial study, a confirmatory study was performed to confirm the passing Antimicrobial Effectiveness results for the autoclaved
After compounding the six formulations, samples were submitted for the initial USP Antimicrobial Effectiveness testing per USP and SOP-00181. All test samples were challenged with approximately 1.0×10 to 1.0×106 cfu/mT, of S. aureus ATCC 6538, P. aeruginosa ATCC 9027, E. coli ATCC 8739, C. albicans, ATCC 10231 and A. niger, ATCC 16404. The organisms were inoculated into a 50 mL centrifuge tube containing 10 mL of test sample at Time=O. One (1) mL was aliquoted from each centrifuge tube for the following 4 weeks. The log reduction was determined by the plate count method after 7 14, 21 and 28 days by diluting in DEB from 10″1 to 10−4 for bacteria/yeast and 10−1 to 1−′ for mold. The plates were then poured with the appropriate media and incubated. Bacterial plates were poured with SCDA and incubated at 32.5±20.5° C.. Yeast/mold plates were poured with SDA and incubated at 22.5±2.5° C.. The initial antimicrobial effectiveness data was reviewed before any further testing for antimicrobial effectiveness was conducted. Only formulas that had met the acceptance criteria at the initial testing were followed beyond the initial testing.
The acceptance criteria for USP Antimicrobial Effectiveness for a Category 1 item are:
Bacteria—7 day—Not less than 1.0 log reduction from initial count
Yeast/Molds—7 and 14 days—No increase from initial count
Samples of each formulation were pulled from all storage conditions every two weeks and analyzed for chlorine dioxide, pH, and osmolality.
The analytical testing of the dyphylline/chlorine dioxide samples showed a pH drift upward in both the autoclaved and non-autoclaved formulations, with the higher temperatures demonstrating a more dramatic pH change (see Table 4). There were no apparent changes in osmolarity in all samples at all storage conditions (Table 5). The chlorine dioxide concentration in the dyphylline/chlorine dioxide samples showed no clear trend (Table 6).
For the antimicrobial effectiveness testing, the initial formulations (both autoclaved and non-autoclaved), met the acceptance criteria. For the last (four month) time point, samples of the autoclaved formulation at all storage conditions were tested for antimicrobial effectiveness. The samples of the autoclaved formulation stored at 5° C., 25° C. % 60% RH, and 40° C./75% RH all met the acceptance criteria for USP Antimicrobial Effectiveness after four months (see Tables 7-11).
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
During the 3 months of testing, pH of both autoclaved and non-autoclaved increased in all conditions (see Table 12). There were no apparent changes in osmolality for all samples at all storage conditions (Table 13). The chlorine dioxide concentration showed no clear trend (see Table 14). These samples did not meet specification for USP Antimicrobial Effectiveness for the initial testing (Tables 15 and 16).
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
During the execution of the initial study, a confirmatory study was performed to confirm the passing antimicrobial results for the autoclaved dyphylline/chlorine dioxide sample. In addition to this sample, an autoclaved chlorine dioxide formulation and a formulation based on example 5 of U.S. Pat. No. 6,024,954, consistent with the Refresh product marketed by Allergan were prepared for the confirmatory studies. All three were analyzed in the USP Antimicrobial Effectiveness test, and the earlier tests were confirmed with the dyphylline/chlorine dioxide and the formulation based on example 5, U.S. Pat. No. 6,024,954 (consistent with Refresh) passing through 28 days, and the chlorine dioxide alone sample failing at day 7 (see Tables 17-19).
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
S. aureus
P. aeruginosa
E. coli
C. albicans
A. niger
Samples of the dyphylline/chlorine dioxide formulation stored at 5° C., 25° C./60% RH and 40° C./75% RH met the criteria for USP Antimicrobial Effectiveness for a Category 1 item after four months of storage.
The chlorine dioxide only formulation samples did not meet the acceptance criteria for the USP Antimicrobial Effectiveness testing for a Category 1 item.
The confirmatory Antimicrobial Effectiveness testing did confirm the observed results of the initial Antimicrobial Effectiveness testing for the dyphylline/chlorine dioxide and chlorine dioxide formulations. The dyphylline/chlorine dioxide formulation again met the acceptance criteria for USP Antimicrobial Effectiveness for a Category 1 item. The chlorine dioxide formulation did not meet the acceptance criteria for USP Antimicrobial Effectiveness for a Category 1 item. During the same testing, the formulation based on example 5, U.S. Pat. No. 6,024,954 (consistent with Refresh) also met the acceptance criteria for USP Antimicrobial Effectiveness for a Category 1 item.
The contents of all references, patents, pending patent applications and published patents, cited throughout this application are hereby expressly incorporated by reference.
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
