HK1130665B - Ophthalmic compositions comprising povidone-iodine - Google Patents

Description

Ophthalmic composition comprising povidone-iodine

Related applications

This application claims the benefit of priority to U.S. Application Serial No. 11/636,293, filed December 7, 2006, U.S. Provisional Application Serial No. 60/782,629, filed March 14, 2006, and U.S. Provisional Application Serial No. 60/848,315, filed September 29, 2006. All patents, patent applications, and references cited anywhere in this specification are hereby incorporated by reference in their entirety.

Background of the Invention

Infectious conjunctivitis is an ophthalmic condition characterized by inflammation of the conjunctiva secondary to microbial invasion. Microorganisms that can cause conjunctivitis in the human body include bacteria (including mycobacteria), viruses, fungi, or amebas. Current treatments for bacterial conjunctivitis include antibiotic drops. Since antibiotic drops are ineffective in suppressing viral conjunctivitis, treatment of this infection can only alleviate symptoms. Treatments for fungal and amebic conjunctivitis include a few optional drug therapies, which lack antibacterial or antiviral efficacy and are toxic to the ocular surface.

Diagnosis of the different pathogens in infectious conjunctivitis, such as bacteria, viruses, or fungi, is not economically feasible because accurate diagnosis requires complex laboratory cultures that are not easily incorporated into routine healthcare practice. Because accurate diagnostic methods are not practical, most conjunctivitis is presumed to be bacterial without bacterial culture and treated with antibiotics. Antibiotic treatment is not optimal because it is ineffective for viral or fungal conjunctivitis.

The use of steroids in ocular infections is being explored cautiously. Although steroids have the advantage of reducing the severity of inflammation in acute infections, they are also known to increase susceptibility to some infections.

Topical corticosteroids are often used to control ophthalmic inflammation. Their mechanism of action involves suppressing the immune response and concurrent tissue destruction that may result from excessive inflammation. Corticosteroids have adverse side effects that limit the body's inherent ability to resist infection. In fact, inappropriate steroid use can exacerbate the course of infections secondary to mycobacteria, viruses, or fungi. Due to these obvious risks, it is only recommended that antibiotic-steroid combination therapy be used for ocular infections under the careful observation of a trained ophthalmologist. In fact, the most commonly used compound ophthalmic antibiotic-steroid drug, ^{Diphenhydramine} (Alcon), clearly lists "viral diseases of the cornea and conjunctiva, mycobacterial infections, and fungal infections" as absolute contraindications for its use. Obviously, these compound drugs are not intended to be used on surfaces of infectious conjunctivitis where bacterial infection cannot be confirmed.

In summary, there is currently no single ophthalmic antimicrobial drug with broad-spectrum activity against all forms of conjunctivitis or keratitis, and current antimicrobial/steroid or antimicrobial/NSAID combinations have not been shown to be safe for use in infectious conjunctivitis or keratitis that may be caused by viruses or fungi.

Summary of the Invention

The present invention provides an ophthalmic composition comprising 0.01% to 10% (weight/weight or weight/volume) povidone-iodine in combination with an anti-inflammatory drug, a steroid, or a combination of an anti-inflammatory drug and a steroid. In a preferred embodiment, the povidone-iodine (PVP-I) content is between 0.1% and 2.5%, 0.5% and 2%, 0.75% and 2%, 0.8% and 2%, 0.9% and 2%, 1% and 2%, or 1% and 1.5%. In another embodiment, the combined weight of PVP-I, anti-inflammatory drug, and steroid is between 0.1% and 4.5%. The solution is used to treat conjunctival and corneal infections. The broad spectrum of povidone-iodine allows the combination to be used for mycobacterial, viral, fungal, and amebic infections of the conjunctiva or cornea, unlike existing combination antibacterial-steroid ophthalmic compositions, which are contraindicated for these infections. Additionally, the solution is useful for infection prevention and inflammation control in patients recovering from recent ophthalmic surgery. Existing antimicrobial/anti-inflammatory drugs or antimicrobial/steroid combinations are not indicated for the treatment of viral, fungal, mycobacterial, and amebic infections in the postoperative period.

One embodiment of the present invention relates to an ophthalmic composition suitable for external application to the eye, effective for treating and/or preventing microbial infections or conditions of at least one ocular tissue. For example, the disease prevention can include preventing postoperative infections, preventing postnatal infections in newborns, or preventing accidental injuries from contact with contaminants. Accidental injuries from contact with contaminants can occur, for example, during surgical procedures or food processing. The composition comprises povidone-iodine at a concentration between 0.01% and 10%, and an anti-inflammatory agent, a steroid, or a combination thereof.

The mammalian eye can be divided into two main sections: the anterior segment and the posterior segment. The anterior segment, the front third of the eye, contains the tissues in front of the vitreous humor: the cornea, iris, ciliary body, and lens. Within the anterior segment are two fluid-filled spaces: the anterior chamber and the posterior chamber. The anterior chamber is located between the back of the cornea (i.e., the corneal endothelium) and the iris. The posterior chamber is located between the iris and the front surface of the vitreous humor. The posterior segment, the back two-thirds of the eye, contains the vitreous membrane at the front and all the tissues behind it: the vitreous humor, retina, choroid, and optic nerve. In some animals, the retina includes a reflective layer (tachycardia) that increases the amount of light detected by each photoreceptor cell and allows these animals to see better in dim conditions.

It has been surprisingly found that the combination of povidone-iodine and a steroid eliminates the undesirable irritation to the eye caused by PVP-I when present in an appropriate pH range. The present invention provides aqueous suspensions of water-insoluble drugs that are pH-stable and maintain this state even after storage for extended periods of time.

In a preferred embodiment, the ophthalmic composition contains povidone iodine at a concentration of between 0.1% and 2.5% by weight, or more preferably, between 0.5% and 2%. In another preferred embodiment, the ophthalmic composition contains povidone iodine, anti-inflammatory drugs, and steroids at a total weight of between 0.1% and 2.5% (weight to volume, or weight to weight), or between 0.1% and 4.5%.

The steroid concentration in the ophthalmic composition may be between 0.01 and 10%. In a preferred embodiment, the steroid concentration is between 0.05 and 2%.

The ophthalmic composition may further include (1) a local anesthetic to relieve pain; (2) a penetration enhancer (which may be a local anesthetic) to promote penetration of povidone iodine into the ocular tissue; (3) an antimicrobial preservative, for example, at a concentration of about 0.001% to 1.0% by weight; (4) a cosolvent or nonionic surfactant-surfactant, for example, at a concentration of about 0.01% to 2% by weight; (5) a viscosity increasing agent, for example, at a concentration of about 0.01% to 2% by weight; and (6) a suitable ophthalmic carrier.

The ophthalmic composition can be in the form of a solution, suspension, emulsion, ointment, cream, gel, or a controlled release/slow release carrier. For example, the composition can be in the form of a contact lens solution, an eye wash, eye drops, and the like.

The ophthalmic composition can be used to treat and/or prevent microbial infections. The microorganisms can be bacteria, viruses, fungi, or amoebas, parasites, or combinations thereof. The bacteria can be mycobacteria. Furthermore, the solution can be used to treat or prevent diseases such as conjunctivitis, corneal abrasions, ulcerative infectious keratitis, epithelial keratitis, stromal keratitis, and keratitis associated with herpes viruses.

For example, the ophthalmic composition may comprise the following components: 0.5 to 2% (w/w) povidone-iodine complex; 0.05 to 2% (w/w) steroid; 0.005 to 0.02% (w/w) EDTA (ethylenediaminetetraacetic acid); 0.01 to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5 to 2% (w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose, with a pH ranging from 5 to 7. More preferably, the ophthalmic composition may comprise the following components: 1.0% (w/w) povidone-iodine complex; 0.1% (w/w) steroid; 0.01% (w/w) anhydrous EDTA; 0.3% (w/w) sodium chloride salt; 0.05% (w/w) tyloxapol; 1.2% (w/w) sodium sulfate; and 0.25% (w/w) hydroxyethyl cellulose; with a pH range of 5.5 to 6.5. In one embodiment, the composition consists essentially of 0.5 to 2% (w/w) povidone-iodine complex; 0.05 to 2% (w/w) steroid; 0.005 to 0.02% (w/w) EDTA (ethylenediaminetetraacetic acid); 0.01 to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5 to 2% (w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose; and a pH range of 5 to 7. In another embodiment, the composition consists essentially of 1.0% (w/w) povidone-iodine complex; 0.1% (w/w) steroid; 0.01% (w/w) EDTA sodium salt; 0.3% (w/w) sodium chloride salt; 0.05% (w/w) tyloxapol; 1.2% (w/w) sodium sulfate; and 0.25% (w/w) hydroxyethylcellulose; with a pH ranging from 5.5 to 6.5.

Of course, it is known that EDTA can be in various forms, such as the free acid, disodium salt, or tetrasodium salt. The steroid can be dexamethasone, prednisolone, or prednisone. These steroids can be in the form of sodium phosphate salts (e.g., dexamethasone sodium phosphate, prednisolone sodium phosphate, or prednisone sodium phosphate) or acetate salts (e.g., dexamethasone acetate, prednisolone acetate, or prednisone acetate). Prednisolone is the active metabolite of prednisone, and it is known that prednisolone can be used in place of prednisone.

In a preferred embodiment, the ophthalmic composition retains at least 90% of the PVP-I and at least 90% of the steroid 1 month, 2 months, 3 months, 6 months, or 1 year after preparation. This can be achieved by preparing the ophthalmic composition according to at least the above formulation (e.g., the first two paragraphs). This stability is maintained even when the composition is stored at room temperature under an indoor lighting environment of 100 lux to 1000 lux. In a preferred embodiment, the composition is an aqueous solution.

In another embodiment, the present invention relates to a method for treating and/or preventing an ophthalmic condition or a microbial infection of at least one ocular tissue, comprising the step of administering to the eye one of the various doses of the ophthalmic compositions discussed above. The ophthalmic condition can be, for example, a microbial infection of at least one ocular tissue, conjunctivitis, corneal abrasions, ulcerative infectious keratitis, epithelial keratitis, stromal keratitis, and herpes virus-associated keratitis. The microorganism can be a bacterium (e.g., mycobacterium), a virus, a fungus, or an ameba.

In the above methods, treatment can include administering a solution of the present invention, wherein the total amount of povidone-iodine, the anti-inflammatory agent, and the steroid is 0.001 mg to 5 mg per dose. Furthermore, the dose volume can be between 10 microliters and 200 microliters, or between 50 microliters and 80 microliters; approximately one drop per eye. Administration can be 1 to 24 times a day, 2 to 4 times a day, or 2 to 24 times a day.

In one embodiment, the method further comprises storing the solution for at least one month, at least two months, at least three months, at least six months, or at least one year prior to administration. Storage can be in a transparent bottle (a substantially light-proof container) in a light environment. The light environment can be, for example, an outdoor light environment with approximately 100 lux to 1000 lux of light.

Detailed Description of the Invention

In a preferred embodiment, the composition of the present invention is for topical administration. The dosage range is 0.001 to 5.0 mg per eye; the numerical values recited represent the sum of three compounds: the anti-inflammatory agent, povidone iodine, and the local anesthetic. A dosage for one eye can be understood as approximately one drop of solution. One drop of solution is approximately between 10 μl and 200 μl, between 20 μl and 120 μl, or between about 50 μl (microliters) and about 80 μl of solution, or any volume therebetween. For example, a pipette such as a pipette manager can administer drops of at least 1 μl to 300 μl, and any volume therebetween.

In a preferred embodiment, the solution can be administered as an eye drop using any of the many types of eye drop pipettes available on the market. Although not required, the containers used for the compositions of the present invention can be transparent, translucent, and opaque, and can include other properties or combinations of properties, such as glass lining, tamper-proofing, packaging for single or several doses, and combinations thereof.

Povidone iodine has the following structure:

Anti-inflammatory drugs suitable for the compositions and methods of the present invention include at least the following: ketotifen fumarate, diclofenac sodium, flurbiprofen sodium, ketorolac tromethamine, suprofen, celecoxib, naproxen, rofecoxib, or derivatives or combinations thereof. Ketorolac (also known as ketorlac or ketorolac tromethamine) is a nonsteroidal anti-inflammatory drug (NSAID) in the propionic acid family.

Anti-inflammatory drugs suitable for the compositions and methods of the present invention include at least: dexamethasone, dexamethasone alcohol, dexamethasone sodium phosphate, fluorometholone acetate, fluorometholone alcohol, loteprendol etabonate, medrysone, prednisolone, prednisone, prednisolone acetate, prednisolone sodium phosphate, rimexolone, hydrocortisone, hydrocortisone acetate, lodoxamide tromethamine, or derivatives or combinations thereof. It is understood that all compounds herein may be in various modified forms, such as acetate, sodium phosphate, sodium salt, and the like.

Dexamethasone has the following structure:

It is known that any reagent mentioned in each place herein can be in the form of chemical equivalents, such as salts, hydrides, esters and other modifications of basic compounds. For example, dexamethasone in any composition and method of the present invention can be replaced by any of its derivatives, including its esters or salts. Examples of the derivatives include at least dexamethasone-17-acetate (CAS Registry No.: 1177-87-3), dexamethasone disodium hydrogen phosphate (CAS Registry No.: 2392-39-4), dexamethasone valerate (CAS Registry No.: 14899-36-6), dexamethasone-21-isonicotinate (CAS Registry No.: 2265-64-7), dexamethasone palmitate (CAS Registry No.: 33755-46-3), dexamethasone propionate (CAS Registry No.: 55541-30-5), dexamethasone furoate (CAS Registry No.: 83880-70-0), dexamethasone-21-galactoside (CAS Registry No.: Dexamethasone derivatives are also described in U.S. Patent No. 4,177,268.

Local anesthetics suitable for the compositions and methods of the present invention include at least proparacaine, lidocaine, tetracaine, or derivatives or combinations thereof.

The compositions of the present invention may be administered as a solution, suspension, emulsion (dispersion), gel, cream, or ointment in an ophthalmically acceptable carrier.

In compositions herein for topical administration (e.g., topical administration to the eye), the mixture is preferably formulated as a 0.01 to 2.0% solution by weight in water at a pH of 5.0 to 8.0 (values refer to the combined presence of povidone-iodine and dexamethasone). This pH range can be achieved by adding a buffer to the solution. Surprisingly, it has been found that the compositions of the present invention are stable in buffered solutions. That is, there are no adverse interactions between the buffer and the iodine or other components that would render the composition unstable. While the exact dosage regimen is left to the discretion of the clinician, topical application of the resulting solution is recommended as one drop per eye 1 to 24 times daily. For example, the solution may be applied 1, 2, 4, 6, 8, 12, 18, or 24 times daily.

antimicrobial preservatives

As an optional component, a suitable antimicrobial preservative may be added to prevent contamination of the multi-dose packaging. Such agents include benzalkonium chloride, thimerosal, chlorobutanol, methylparaben, propylparaben, phenylethyl alcohol, EDTA, sorbic acid, polychloridium chloride, other agents known to those skilled in the art, or combinations thereof. Generally, the concentration of the preservative used is 0.001% to 1.0% by weight.

Cosolvent/Surfactant

The compositions of the present invention contain optional cosolvents. The solubility of the components in the compositions can be enhanced by using surfactants or other suitable cosolvents in the composition. Such cosolvents/surfactants include polysorbates 20, 60, and 80, polyoxyethylene/polyoxypropylene surfactants (e.g., Pluronic F-68, F-84, and P-103), cyclodextrins, tyloxapol, other agents known to those skilled in the art, or combinations thereof. Generally, the cosolvent concentration used is 0.01% to 2% by weight.

adhesive

The compositions of the present invention optionally contain a viscosity-increasing agent—an agent that increases viscosity. Increasing the viscosity of the single aqueous solution can improve absorption of the active compound by the eye; reduce variability during dispensing; reduce spontaneous separation of components of a suspension or emulsion within the formulation; and/or otherwise improve the quality of the ophthalmic formulation. Such viscosity-increasing agents include, for example, polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, other agents known to those skilled in the art, or combinations thereof. These agents are typically used at a concentration of 0.01% to 2% by weight.

preparation

The following two reactions are considered to be the chemical reactions that PVP-I undergoes in aqueous solution:

The reactivity of free iodine ( _I2 ) with -OH, -SH, and -NH functional groups is well described in the literature and forms the basis of the antimicrobial activity of iodine-containing solutions (Rackur HJ Hasp. Infect., 1985; 6: 13-23, and references cited therein). Dexamethasone (9-fluoro-11β,17,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione) contains three -OH groups at positions 11, 17, and 21. One skilled in the art would conclude that these hydroxyl groups would readily undergo covalent substitution reactions with the free iodine generated in the solution equilibrium reaction described above for PVP- _I2 .

In developing this formulation, various combinations of anti-inflammatory drugs and PVP-I, or steroids and PVP-I, were tested. We observed that most formulations were unsuccessful due to the rapid reaction between PVP-I and the added drug (anti-inflammatory drug or steroid). Some of these unsuccessful formulations are described elsewhere herein. Specifically, the low concentration of the PVP-I solution was a limiting factor in its stability and effectiveness as a bactericidal agent.

Therefore, the present invention aimed to develop a novel combination formulation of PVP-I and an anti-inflammatory drug that addresses the three challenges of stability, efficacy, and non-irritation to the eye. Surprisingly, we discovered that a 1% PVP-I solution, when combined with dexamethasone, is effective for the treatment or prevention of infections. Previous literature has suggested that when 1% PVP-I was attempted, side effects from ocular administration precluded its use. Undesirable side effects include pain and irritation.

We were surprised to find that the PVP-I and dexamethasone solutions remained stable for many months. Based on published stability data, we hypothesize that the compositions of the present invention are stable for several years, although experiments on this point are still ongoing. Even more surprising was the lack of any observable reaction between dexamethasone and PVP-I over time at room temperature in the light or in the dark. Surprisingly, despite mixing in our formulation, no reaction occurred between the free iodine in the solution and the hydroxyl groups present in the dexamethasone molecule.

Due to the extreme oxidizability of PVP-I, conventional practitioners/scientists/physicians in the field did not believe that a stable combination of PVP-I and dexamethasone could be achieved. We observed that stable formulations of this combination could be achieved at concentrations greater than 0.5% PVP-I. Surprisingly, we found that the stability of the 0.3% PVP-I and dexamethasone combination was relatively low. This was surprising, as lower concentrations of iodine are generally considered less reactive and therefore less damaging to both agents. After 8 weeks, the amount of iodine available in the combination (initially 0.3% PVP-I) had decreased by 20%. Although it has been suggested that a 0.1% diluted PVP-I exhibits the greatest antimicrobial activity (Gottardi W. J. Hosp. Infect., 1985;6(Suppl):1-11), our data suggest that a combination of at least 0.5% PVP-I and dexamethasone is required for optimal antimicrobial activity. We have observed that PVP-I reacts rapidly with ketorolac (a nonsteroidal anti-inflammatory drug) and that ketorolac is completely consumed with a substantial reduction in the iodine available in the PVP-I complex, depending on the ratio of ketorolac to PVP-I. A combination of PVP-I and dexamethasone sodium phosphate has also proven less successful, but still useful. We observed that after 12 weeks, the PVP-I complex partially decomposes into an unknown multimeric complex that appears under UV spectroscopy and that the iodine is reduced by approximately 5%. We further observed that PVP-I reacts rapidly with proparacaine and rapidly releases free iodine.

Surprisingly, this combination formulation improves the stability of dilute PVP-I solutions. After 5 weeks of storage, the available iodine content of a 0.625% povidone-iodine solution at 25°C was 91% and at 4°C was 98%. (Iryo Yakugaku 2003, 29(1), 62-65). Our data demonstrate that our formulation stabilizes dilute PVP-I solutions. After 8 weeks at room temperature, the available iodine content of solutions containing 0.5% and 1% PVP-I exceeded 99%.

Topical steroids alone are contraindicated in undiagnosed viral and fungal infections of the human eye. Furthermore, combined use of antimicrobial/steroid solutions is contraindicated in undiagnosed viral infections. There are no reports demonstrating the safety and efficacy of steroid-containing solutions for undiagnosed viral or fungal infections of the human eye. Therefore, the authors and others skilled in the art are unsure of the use of steroid-containing solutions for acute viral or fungal eye infections.

Potentially destructive ocular immune responses in active infection settings limit the use of potent anti-inflammatory steroids. However, due to the antimicrobial (antibacterial, antiviral, and antifungal, antiprotozoal) efficacy of PVP-I, the compound is useful in active infection settings without the risk of exacerbating the infection. This unique property (broad-spectrum antimicrobial and potent anti-inflammatory) represents a significant improvement over other ophthalmic antibiotics and anti-inflammatory drugs.

Although topical steroids are highly effective in treating ophthalmic inflammation, their use is associated with risks. Topical ophthalmic steroids act through a number of well-documented genetic and non-genetic mechanisms, reducing the production of proteins involved in the inflammatory cascade, decreasing vascular permeability, reducing the production of proinflammatory cytokines, decreasing the titer of soluble inflammatory factors, inhibiting the production of acute-phase proteins, reducing leukocyte migration, and increasing cell membrane stability. Through all of these mechanisms, topical steroids can reduce the local concentration of active substances that are toxic to the eye, including proteins from the gelatinase, collagenase, and matrix metalloproteinase families. This reduction in potential toxic substances is accompanied by a prolonged infection and increased risk of infection. The risks of these topical steroids can be reduced and/or eliminated if they are coadministered with appropriate antimicrobial agents (i.e., antibacterials for bacterial infections, antivirals for viral infections, and antifungals for fungal infections). The average trainee ophthalmologist cannot accurately identify the pathogen in most cases of acute external ocular infections within a short period of time, which is closely related to the treatment prescribed. Thus, the beneficial effects of immediate topical steroid use are delayed or lost entirely as clinicians await culture results or, more likely, delay treatment. The novel combination of a broad-spectrum microbicide effective against bacteria, viruses, and fungi with a topical steroid eliminates this risk and allows for prompt control of inflammation and eradication of the pathogen. In our opinion, this is the most preferred embodiment of the present invention.

We also note that the other components in our preferred composition appear to further stabilize the formulation. That is, EDTA, sodium chloride, tyloxapol, sodium sulfate, and hydroxyethylcellulose appear to have an additional effect in stabilizing the composition.

Although certain preferred embodiments are incorporated herein by reference in describing the present invention, variations thereof will be apparent to those skilled in the art, and the present invention is not intended to be limited thereto. All patents, patent applications, and references incorporated herein by reference in their entirety.

Example

The letter "A" in the sample names throughout this section refers to povidone-iodine complex ("PVP-I"), A00 refers to 0.0% PVP-I, A03 refers to 0.3% PVP-I, A05 refers to 0.5% PVP-I, A10 refers to 1.0% PVP-I, A15 refers to 1.5% PVP-I, A20 refers to 2.0% PVP, A40 refers to 4.0% PVP-I, and so on.

Similarly, the letters "B, C, D, K, P" in the sample names refer to dexamethasone, dexamethasone sodium phosphate, prednisolone sodium phosphate, ketorolac (also known as ketorlac), and proparacaine, respectively. B00 refers to 0.0% dexamethasone, B01 refers to 0.1% dexamethasone, C01 refers to 0.1% dexamethasone sodium phosphate, D01 refers to 0.1% prednisolone sodium phosphate, K01 refers to 0.1% ketorolac, and P008 refers to 0.08% proparacaine, etc.

Example 1: Preparation of Povidone-Iodine/Dexamethasone Suspension

Quantity (wt.%)

Povidone-iodine (PVP-I) 0.0 to 4.0

Dexamethasone, micronized, USP 0.1

EDTA, USP 0.01

Sodium chloride, USP 0.3

Sodium sulfate, USP 1.2

Tyloxapol, USP 0.05

Hydroxyethyl cellulose 0.25

Sulfuric acid and/or

Sodium hydroxide: Adjust pH to 5.7-6.0

Sterile water, USP qs to 100

Experimental process:

To a 1000 mL beaker, add 400 g of sterile water and, under vigorous stirring with an overhead mechanical stirrer, add hydroxyethyl cellulose (2.25 g, 0.25% w/w). Slowly add sodium chloride (2.70 g, 0.3% w/w) and dissolve it, followed by the addition of EDTA (0.09 g, 0.01% w/w) and sodium sulfate (10.8 g, 1.2% w/w). After stirring for 10 minutes, tyloxapol (0.45 g, 0.05% w/w) dissolved in water was transferred to the above solution. The reaction mixture was stirred for 1 hour and sterile water was added to 540 g, followed by stirring for another 10 minutes to obtain "bulk solution 1".

Each 60 g portion of bulk solution 1 was transferred to two 125 mL beakers, and povidone-iodine complex (0.5 g, 1.5 g) was added to each solution while stirring. The pH was adjusted to a range of 5.7 to 6.0 by adding sodium hydroxide or sulfuric acid, and an appropriate amount of sterile water was added to bring the suspension to 100 g, thereby obtaining control samples A05B00 and A15B00, respectively.

Dexamethasone (0.7 g, 0.1% w/w) was added to the remaining 417 g of bulk solution 1 and homogenized for 5 minutes, and then an appropriate amount was added to 420 g to obtain bulk solution 2.

Each 60g portion of bulk solution 2 was transferred to seven 125mL beakers, and povidone-iodine complex (0.0g, 0.3g, 0.5g, 1.0g, 1.5g, 2.0g, and 4.0g) was added to each solution while stirring. The pH was adjusted to a range of 5.7 to 6.0 by adding sodium hydroxide or sulfuric acid, and the suspension was made up to 100g by adding an appropriate amount of sterile water to obtain samples A00B01, A03B01, A05B01, A10B01, A15B01, A20B01, and A40B01, respectively. LC-MS spectra of all samples confirmed the finding that there was no reaction between PVP-I and dexamethasone. The dexamethasone (MH ⁺ = 392.9) peak did not change to other mass spectrometry peaks.

Example 2: Povidone iodine/dexamethasone sodium phosphate solution, povidone iodine/prednisolone sodium phosphate solution and povidone Preparation of ketone iodine/ketorolac solution

A00C01, A03C01, A05C01, A10C01, A15C01, A00D01, A03D01, A05D01, A10D01, A15D01, A00K01, A05K01, A10K01, and A15K01 solutions were prepared in the same manner.

The LC-MS spectra of A05C01, A10C01, and A15C01 confirmed the peak of dexamethasone sodium phosphate (MH ⁺ =472.9), and the LC-MS spectra of A05D01, A10D01, and A15D01 confirmed the peak of prednisolone phosphate (MH ⁺ =440.9).

However, LC-MS experiments for A05K01 and A10K01 confirmed the findings regarding the reaction between PVP-I and ketorolac tromethamine. A05K01 showed a small amount of ketorolac remaining in the sample (MH ⁺ = 256.1), with the main peak at MH ⁺ = 381.9. For A10K01 and A15K01, no ketorolac remained, and all of it had been converted to a new compound (MH ⁺ = 381.9).

LC-MS experiments with A00B01P008 (control), A05B01P008, and A10B01P008 confirmed the findings regarding the reaction between PVP-I and proparacaine. In the control group, two peaks were observed in the LC-MS spectrum: MH ⁺ = 295.1 (proparacaine) and MH ⁺ = 392.9 (dexamethasone). Comparing A05B01P008 with A10B01P008, the proparacaine peak (MH ⁺ = 295.1) became smaller relative to the dexamethasone peak (MH ⁺ = 392.9), suggesting that povidone-iodine reacts with proparacaine.

Example 3: Preparation of Povidone-Iodine/Dexamethasone/Proparacaine Suspension

Weight (wt.%)

PVP-I 0.0 to 1.5

Dexamethasone, micronized, USP 0.1

Proparacaine Hydrochloride, USP 0.08%

EDTA, USP 0.01

Sodium chloride, USP 0.3

Sodium sulfate, USP 1.2

Tyloxapol, USP 0.05

Hydroxyethyl cellulose 0.25

Sulfuric acid and/or

Sodium hydroxide: Adjust pH to 5.7-5.9

Sterile water, USP qs to 100

To a 400 mL beaker, 100 g of sterile water was added. Hydroxyethylcellulose (0.75 g, 0.25% w/w) was added while stirring vigorously with an ARROW overhead mechanical stirrer. Sodium chloride (0.9 g, 0.3% w/w) was slowly added and dissolved, followed by the sequential addition of EDTA (0.03 g, 0.01% w/w), sodium sulfate (3.6 g, 1.2% w/w), and proparacaine hydrochloride (0.24 g, 0.08% w/w). After stirring for 10 minutes, tyloxapol (0.15 g, 0.05% w/w) dissolved in water was transferred to the above solution. The reaction mixture was stirred for 1 hour and dexamethasone (0.3 g, 0.1% w/w) was added and homogenized for 10 minutes. The solution was then brought to 180 g with an appropriate amount of sterile water to obtain "bulk solution 5." Each 60 g portion of bulk solution 5 was transferred to four 125 mL beakers, and povidone-iodine complex (0.0 g, 0.5 g, 1.0 g) was added to each solution while stirring. The pH was adjusted to approximately 5.8 by adding sodium hydroxide or sulfuric acid, and an appropriate amount of sterile water was added to bring the suspension to 100 g, thereby obtaining samples A00B01P008, A05B01P008, and A10B01P008.

During the preparation of these samples, a strong iodine odor was observed. We suspected that PVP-I reacted very rapidly with proparacaine. This suspicion was confirmed by LC-MS spectra. The dexamethasone and proparacaine peaks were significantly reduced or even disappeared in these combined samples with PVP-I.

Stability of solution

After storing the various samples at room temperature for several weeks, the total amount of titratable iodine in the solution was determined by titration.

Titration: Pipette 5 mL of each sample into a 125 mL beaker and add 1 mL of 1% (w/v) starch indicator solution. Titrate this solution with 0.0025 N sodium thiosulfate solution until the blue color disappears. Determine the volume of sodium thiosulfate used.

Titratable iodine (mg) = V (mL, volume used for titration) ^* 12.69 (mg/mL) / 2

The calculated titratable iodine (mg) is listed in Table 1.

Table 1. Summary of Stability Data (Available Iodine)

Povidone-iodine concentration data after several weeks of storage at room temperature in the dark or under light conditions suggest that stable combination formulations have been obtained: povidone-iodine with dexamethasone, or dexamethasone sodium phosphate or prednisolone sodium phosphate. The combination of 0.3% (wt.%) PVP-I with dexamethasone was less stable than the aforementioned 0.5% povidone-iodine with dexamethasone combination, which showed only a 5% change in available iodine concentration after 8 weeks.

The data also suggest that PVP-I reacts with ketorolac tromethamine. After five weeks in the sample at 0.5% PVP-I, no titratable iodine remained. At 1.5% and 1.5% PVP-I in the sample, titratable iodine significantly decreased by 58.8% and 36.3%, respectively.

Stability testing of dexamethasone in samples using HPLC

The USP method was used. The concentration data for dexamethasone are tabulated in Table 2 below:

Table 2

sample Initial concentration (mg/mL)/3 weeks Concentration (mg/mL)/7 weeks Concentration change% CLS-A05B01 0.94 0.92 -2.13 CLS-A10B01 0.86 0.90 4.65 CLS-A15B01 0.93 0.86 -7.53

HPLC chromatogram showed that no new peaks appeared compared with the standard control group, and the spectrum indicated that there was no reaction between povidone iodine and dexamethasone.

Stability test of dexamethasone sodium phosphate in samples using HPLC

The USP method was used. The concentration data of dexamethasone sodium phosphate are listed in Table 3 below in a graph. A05C01 (1 day), A10C01, A15C01 (3 days) were placed in a 40°C incubator.

Table 3.

Sample name Initial concentration (mg/mL) Concentration (mg/mL) Concentration change% A05C01 1.273 1.244 -2.28 A10C01 0.948 1.075 13.40 A15C01 1.355 1.148 -15.28

HPLC chromatograms showed that new peaks appeared in samples A10C01 and A15C01 compared with the standard control group and A05C01. The concentration of dexamethasone sodium phosphate in samples A10C01 and A15C01 changed by more than 10%.

In another experiment, we surprisingly found that the following formulation of eye drops was stable for 1 month, 3 months, and even 6 months: 0.5 to 2% (w/w) povidone-iodine complex; 0.05 to 0.2% (w/w) steroid; 0.005 to 0.02% (w/w) EDTA; 0.0.1 to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5 to 2% (w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose; wherein the steroid was dexamethasone, prednisolone, prednisone, or its acetate or sodium phosphate forms. Based on the data collected to date, such solutions appear to be shelf-stable for at least one year from the date of their preparation. Stability is defined as a deviation of less than 10% in the concentrations of the major components (PVP-I and steroid) over time. Thus, when the solution is stored, and based on our 6-month data, the amount of PVP-I decreases by less than 90% over the 1-month, 3-month, and 6-month periods, it appears that the solution will remain stable for at least one year. Storage conditions were room temperature, clear bottles, and room lighting of 100 to 1000 lux of incandescent and/or fluorescent light. The stability can be attributed to the unique combination of PVP-I and dexamethasone, prednisolone, and prednisone (including the acetate and sodium phosphate forms of these steroids). We also found that the presence of other agents (EDTA, sodium chloride, tyloxapol, sodium sulfate, and hydroxyethylcellulose) further enhanced stability.

We have found that PVP-I contributes a number of advantages to the formulation when compared to various formulations during development. Briefly, the PVP-I formulation has the following improved properties compared to iodine solutions: (1) less irritation to skin and eyes, (2) washability, (3) increased stability, (4) increased stability to light, (5) lower systemic toxicity, and (6) fewer side effects. Furthermore, based on current knowledge, PVP-I does not cause scar tissue formation.

Example 4. Antimicrobial Assay

Solutions of povidone-iodine combined with various anti-inflammatory steroids were tested for their antimicrobial activity against common pathogens, yeasts, fungi, and viruses. The USP antimicrobial assay (inoculation) culture medium method was used to test the efficacy of various concentrations of povidone-iodine combination solutions against pure ocular isolates. Povidone-iodine was found to inhibit microbial growth in a dose-dependent manner starting at a concentration of 0.03%. Cultures treated with the 0.03% solution within 72 hours completely eliminated all tested species, further supporting its antimicrobial activity. Optimal antimicrobial efficacy was achieved at concentrations greater than 0.5%. At concentrations greater than this, the solution effectively killed and eliminated all tested bacterial species, even in direct contact without further incubation. For example, 1% povidone iodine and 0.1% dexamethasone (wt %) were found to kill Pseudomonas aeruginosa, Proteus mirabilis, Serratia maracescens, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, penicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Candida parapsilosis, Candida albicans, and Aspergillus niger upon contact. This result clearly demonstrates the effectiveness of the solution in eliminating microbial growth.

Example 5. Adenovirus Experiment

Povidone-iodine combined with dexamethasone was tested for antiviral activity against human adenovirus. 0.5 mL aliquots of each test and control were combined with 0.5 mL of virus in sterile tubes. The tubes were then incubated at 37°C for 30 minutes. A00B01 was used as a positive control. Hank's Balanced Salt Solution (HBSS) was used as a negative control. Following incubation, the test and control samples were titrated for infectious HAdV-4.

Table 4. Antiviral activity

Sample No. A00B01 4.4 A10B01 ≤1.6 A15B01 ≤1.6 A20B01 ≤1.6 HBSS 4.0

After incubation of the virus-laden samples for 30 minutes, A00B01 had no effect on viral infectivity, but the mixtures A10B01, A15B01, and A20B01 resulted in complete inactivation of the virus.

Example 6. Human eye irritation study

All volunteers were examined prior to testing and found to have healthy eyes without symptoms. A single 1.0% povidone-iodine solution was prepared and tested on 15 healthy volunteers. Side effects of treatment were promptly reported. Observed side effects included mild pain, discomfort, tearing, and redness. This is consistent with previous literature indicating that 1% povidone-iodine is unsuitable for use due to unacceptable irritation in patients (e.g., U.S. Patent 5,126,127). The reported side effects clearly indicate that many applications were difficult for the volunteers to tolerate.

A solution of A10B01 containing 1% PVP-I and 0.1% dexamethasone was tested on seven healthy volunteers. It was administered as an eye drop. Surprisingly, the solution was found to be acceptable to the eye (no burning sensation) and comfortable over a range of pH values. In particular, the formulation at pH 5.9 was comfortable to instill in the eye.

A person uses the solution in the form of eye drops four times daily for three days with no adverse side effects.Other pH values, such as pH 6 to 8, are obtained by using suitable chemicals such as sulfuric acid or sodium hydroxide alone, or by adding a suitable buffer.

All volunteers were examined by a doctor immediately after the trial phase and underwent further follow-up examinations over time. Furthermore, the volunteers were allowed to contact the doctor one, two, and three months after the trial, and no volunteer reported any side effects.

Claims (37)

1. An ophthalmic composition suitable for topical administration to the eye, effective for treating and/or preventing microbial infections of at least one ocular tissue, comprising: a) Povidone-iodine with a concentration between 0.5% and 1.0% by weight, and b) A steroid at a concentration of 0.1% by weight, said steroid being selected from dexamethasone alcohol, dexamethasone sodium phosphate, and their salts and combinations thereof. One month after the ophthalmic composition was prepared, the composition retained at least 90% steroids and at least 90% povidone-iodine by weight. 2. The ophthalmic composition of claim 1, wherein the composition further comprises a local anesthetic for pain relief. 3. The ophthalmic composition of claim 2, wherein the local anesthetic is selected from paracaine, lidocaine, tetracaine, and combinations thereof. 4. The ophthalmic composition of claim 1, wherein the composition further comprises a penetration enhancer that promotes the penetration of povidone-iodine into ocular tissues. 5. The ophthalmic composition of claim 4, wherein the penetration enhancer is a local anesthetic. 6. The ophthalmic composition of claim 1, wherein the composition further comprises an antibacterial preservative. 7. The ophthalmic composition of claim 6, wherein the antibacterial preservative is selected from benzalkonium chloride, thimerosal, chlorobutanol, methylparaben, propylparaben, phenylethyl alcohol, EDTA, sorbic acid, polidocanol, and combinations thereof. 8. The ophthalmic composition of claim 6, wherein the concentration of the antibacterial preservative in the composition is from 0.001% to 1.0% by weight. 9. The ophthalmic composition of claim 1, wherein the composition further comprises a co-solvent/surfactant. 10. The ophthalmic composition of claim 9, wherein the co-solvent/surfactant is selected from polysorbate 20, polysorbate 60, polysorbate 80, prolylonide F-68, prolylonide F-84, prolylonide P-103, cyclodextrin, tylosap, and combinations thereof. 11. The ophthalmic composition of claim 9, wherein the concentration of the co-solvent/surfactant in the composition is from 0.01% to 2% by weight. 12. The ophthalmic composition of claim 1, wherein the composition further comprises a thickener. 13. The ophthalmic composition of claim 12, wherein the thickener is selected from polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, and combinations thereof. 14. The ophthalmic composition of claim 12, wherein the concentration of the thickener in the composition is from 0.01% to 2% by weight. 15. The ophthalmic composition of claim 1, wherein the composition is in the form of a solution, suspension, emulsion, ointment, cream, gel, or controlled-release/sustaining-release carrier. 16. The ophthalmic composition of claim 1, wherein the microorganism is selected from bacteria, viruses, fungi, and amoebae. 17. The ophthalmic composition of claim 16, wherein the bacteria is mycobacterium. 18. The ophthalmic composition of claim 1, wherein the microbial infection of at least one ocular tissue is selected from conjunctivitis, ulcerative keratitis, epithelial keratitis, stromal keratitis, and herpesvirus-associated keratitis. 19. The ophthalmic composition of claim 1, wherein the prevention is prevention of corneal abrasion or infection following ophthalmic surgery. 20. The ophthalmic composition of claim 1, comprising: 0.5 to 1.0% (w/w) povidone-iodine; 0.1% (w/w) steroids; 0.005% to 0.02% (w/w) EDTA; 0.01 to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) Tyrosine; 0.5% to 2% (w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethyl cellulose; The steroid is selected from the form of dexamethasone sodium phosphate. 21. The ophthalmic composition of claim 1, comprising: 1.0% (w/w) povidone-iodine; 0.1% (w/w) steroids; 0.01% (w/w) EDTA; 0.3% (w/w) sodium chloride salt; 0.05% (w/w) Tyrosine; 0.2% (w/w) sodium sulfate; and 0.25% (w/w) hydroxyethyl cellulose; The steroid is selected from the form of dexamethasone sodium phosphate. 22. The ophthalmic composition of claim 1, wherein the composition retains 90% of its povidone-iodine and 90% of its steroid content after 3 months of exposure to light. 23. The ophthalmic composition of claim 1, wherein the composition retains 90% of its povidone-iodine and 90% of its steroids after one year of exposure to light. 24. The ophthalmic composition of claim 1, wherein the composition is an aqueous solution. 25. Use of one or more doses of the ophthalmic composition of claim 1 in the preparation of a medicament for treating and/or preventing microbial infections of at least one ocular tissue. 26. The use of claim 25, wherein the prevention is the prevention of infection following corneal abrasion or ophthalmic surgery. 27. Use of one or more doses of the ophthalmic composition of claim 1 in the preparation of a medicament for the treatment and/or prevention of an ophthalmic disease, wherein the ophthalmic disease is selected from microbial infection of at least one ocular tissue and corneal abrasion. 28. The use of claim 27, wherein the microbial infection of at least one ocular tissue is selected from conjunctivitis, ulcerative infectious keratitis, epithelial keratitis, stromal keratitis, and herpesvirus-associated keratitis and combinations thereof. 29. The use of claim 25, wherein the microorganism is selected from bacteria, viruses, fungi or amoebas. 30. The use of claim 29, wherein the bacteria is mycobacterium. 31. The use of claim 25, wherein the total amount of said povidone-iodine and steroid is 0.001 mg to 5 mg per dose. 32. The use of claim 25, wherein each dose is between 10 μL and 200 μL. 33. The use of claim 25, wherein each dose is between 50 μL and 80 μL. 34. Use of one or more doses of the ophthalmic composition of claim 1 in the preparation of a medicament for treatment and/or prevention of microbial infection of at least one ocular tissue by administration once to four times a day. 35. Use of one or more doses of the ophthalmic composition of claim 1 in the preparation of a medicament for treatment and/or prevention of microbial infection of at least one ocular tissue by administration once to twenty-four times a day. 36. The use of claim 25, further comprising the step of storing the composition for at least one month, at least three months, at least six months, or at least one year prior to the administration step. 37. The use of claim 36, wherein the preservation is in a light-exposed environment.