This invention relates to products and methods for lowering intraocular pressure within the eye, including treating conditions of glaucoma, by applying analogs of aryloxyand aryl-acetic acids to the affected eye.

Background of the Invention

Glaucoma, as used herein, is any condition of the eye characterized by the therapeutic need to lower intraocular pressure. It may be chronic or acute, and it may result from disease, injury or conventional operative techniques. Glaucoma is a serious condition in that it can cause loss of sight, loss of perception and intense pain. There are various treatments for glaucoma, although none are entirely satisfactory for all indications. A relatively recent advance in the treatment of glaucoma is disclosed in U.S. patent no. 4,757,089 to Dr. David L. Epstein. The '089 patent teaches that elevated intraocular pressure can be relieved by increasing aqueous humor outflow, and that increased aqueous humor outflow can be achieved by treatment with ethacrynic acid or analogs thereof. Aqueous humor outflow is said to be regulated at least in part by the trabecular meshwork of the eye, which contains sulfhydryl groups. The '089 patent teaches that the sulfhydryl-reactive groups of ethacrynic acid molecules react with the sulfhydryl groups of the trabecular meshwork to cause the increase in aqueous humor outflow.

The foregoing approach to treating glaucoma is not without drawbacks. For example, topical aqueous solutions of ethacrynic acid can cause eye irritation. The sulfhydryl-reactive groups of ethacrynic acid have been said to cause this irritation by interacting with sulfhydryl groups in the cornea. Also, ethacrynic acid lacks long term stability in aqueous solution.

Published PCT application WO 92/16199 discloses a further advance by Epstein directed to solving the problem of eye irritation that can be caused by ethacrynic acid. The '199 application teaches combining the ethacrynic acid with a masking agent to "mask" the sulfhydryl-reactive groups from interacting with the sulfhydryl groups of the cornea. The masking agents are selected so as to undergo a Michael Addition reaction with the sulfhydryl

reactive groups of the ethacrynic acid molecules. This reaction is reversible, and it is believed that the masking agent essentially is competitively displaced by the sulfhydryl groups within the trabecular meshwork, only after the ethacrynic acid-masking agent adduct passes through the cornea. Ethacrynic acid is a member of the (aryloxy)acetic acid family of diuretics. The subfamily which ethacrynic acid and its analogs comprise is known as the (acryloylphenoxy)acetic acids. Another subfamily of the (aryloxy)acetic acids are known as the (4-acylphenoxy)acetic acids. This group of compounds, which includes ticrynafen (tienilic acid) and its analogs, differs from the ethacrynic acid-like compounds in that the molecules within this group do not contain sulfhydryl-reactive groups, which can interact with the sulfhydryl groups of the trabecular meshwork. Presumably, compounds such as ticrynafen, which do not contain sulfhydryl reactive groups, could not be used effectively to reduce intraocular pressure and treat glaucoma.

Summary of the Invention

It has been discovered, surprisingly, that molecules of the subfamily (4-acylphenoxy) acetic acids and (4-acylphenyl) acetic acids can lower intraocular pressure when applied to the eye, despite the absence of the sulfhydryl-reactive group believed responsible for the outflow-increasing properties of ethacrynic acid. The methods and products of the invention are particularly useful in treating or preventing the chronic elevation of intraocular pressure that can be associated with glaucoma, as well as the acute elevation of intraocular pressure resulting from conventional operative techniques. They are also useful in therapeutically lowering normal intraocular pressure needed because of damage to the optic nerve.

According to one aspect of the invention, a method for treating or preventing glaucoma is provided. A molecule is administered to the eye in an ophthalmic preparation containing an effective amount of the molecule for treating or preventing glaucoma. The molecule has the formula:

wherein R is selected from the group consisting of acetic acid (-CH ₂ COR ² ), α-methyl-acetic acid (-CHCOR ² ), and

CH ₃ 5 oxyacetic (-OCH ₂ COR ² ) residue,

R ² being selected from the group consisting of hydroxy (OH), lower alkoxy (-O-(CH ₂ )„CH ₃ ), aminoalkoxy (O-(CH ₂ ) _m -NR ³ R ⁴ ), aminoalkylamino (-NH(CH ₂ ) _m NR ³ R ⁴ ), R ³ and R ⁴ being, independently, hydrogen (H) or lower alkyl, n being 0 to 4, and m being 2 to 6; R ¹ is selected from the group consisting of o (a) alkyl or branched alkyl containing 3 to 10 carbon atoms (CH-R ⁶ ),

R ⁵ R ⁵ being hydrogen or lower alkyl ((CH ₂ ) _p CH ₃ ), R ⁶ being lower alkyl ((CH ₂ ) _q CH ₃ ), p being 0 to 2 and q being 1 to 4; s

(b) carbocyclic H ₂ ) _Γ

R'

where R ⁷ is hydrogen or lower alkyl of from 1 to 4 carbon atoms and r is 0-3; and o (c) heteroaromatic or substituted heteroaromatic rings consisting of 5 or 6 atoms of which up to two atoms can be a heteroatom selected from the group consisting of nitrogen, oxygen and sulfur, wherein the substituent on the heteroaromatic ring may be lower alkyl (C,-C ₄ ) or halogen selected from bromo or chloro; and

(d) phenyl or substituted phenyl wherein the substituent on the phenyl is in the s para position and is selected from fluoro, chloro, hydroxy, methoxy, or nitro;

X and Y are independently hydrogen, lower alkyl of from 1-3 carbon atoms, chlorine or bromine.

One preferred compound of the foregoing general formula is: 4-(2-furyl keto) 2,3-dichlorophenoxy acetic acid. Another preferred compound is: 4-(2-N-methylpyrroloyl keto) o 2,3-dichlorophenoxy acetic acid. The most preferred compound is: 4-[2-(5-methylthienyl) keto] 2,3-dichlorophenoxy acetic acid.

According to another preferred aspect of the invention, if the heteroaromatic ring is substituted with a lower alkyl, that substituent is methyl.

The topical treatment may include administration of an ophthalmic delivery enhancing agent as well. According to another aspect of the invention, an ophthalmic preparation is provided. The preparation includes an effective amount of a molecule for treating or preventing glaucoma and a delivery enhancing agent, formulated as a pharmaceutically acceptable, ophthalmic topical preparation, wherein the molecule is embraced by the general formula set forth above.

The active compounds and delivery enhancing agents may be contained in containers constructed and arranged to deliver topically to the eye the ophthalmic preparations. Thus, according to one aspect of the invention, a device constructed and arranged to deliver topically to the eye the above formulation is provided. According to another aspect of the invention, a syringe for delivering an ophthalmic preparation is provided. The syringe delivers to the eye a pharmaceutically acceptable ophthalmic preparation that includes an effective amount of a molecule for treating or preventing glaucoma, the molecule being embraced by the general formula set forth above.

The invention provides effective, non-surgical treatment of glaucoma.

Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof, and from the claims.

Detailed Description of the Invention As described above, the invention involves the lowering of intraocular pressure such as in the treatment of glaucoma. It is known that when therapeutically active molecules bearing sulfhydryl reactive groups are applied to the eye, medically unacceptable side effects can follow. Animal studies have indicated that treatment with these compounds have been associated with irritation such as burning or stinging manifested by prolonged eye closure after topical administration, superficial punctate keratopathy, corneal epithelial stippling, conjunctival hyperemia and discharge. Another such side effect is corneal edema. Corneal edema is a condition evidenced by abnormal accumulation of fluid within the intercellular spaces of the cornea. Clinical symptoms of corneal edema include corneal haziness and increased corneal thickness, apparent upon ophthalmoscopic examination. A major cause of corneal edema is

impaired function of the corneal endothelium, the cell layer covering the inner surface of the cornea, in response to certain chemicals or conditions. The corneal endothelium is known to possess sulfhydryl groups. The present invention involves the unexpected finding that ticrynafen and analogs thereof can accomplish a reduction in intraocular pressure, despite the fact that they do not include sulfhydryl reactive groups which are capable of undergoing a Michael Reaction. According to the invention, medically unacceptable side effects, in particular corneal edema, can be avoided by using a compound which lacks the sulfhydryl reactive groups of the ethacrynic acid molecules. Thus, the use of the compounds embraced by the formula above can increase the margin of safety over the use of therapeutic compounds containing sulfhydryl-reactive groups, allowing for a safe and effective treatment for glaucoma.

The preferred molecules useful in the methods of the invention have a number of properties, now discussed in greater detail. The molecules useful according to the invention are of the general formula set forth above. Particular examples are as follows. The chemical name of ticrynafen is [2,3-dichloro-4-(2-thienylcarbonyl)phenoxy] acetic acid. Ticrynafen has the following chemical formula.

CHOCCHH

A preferred compound is 4-(2-furyl keto) 2,3-dichlorophenoxy acetic acid with the following chemical formula.

Another preferred compound is 4-(2-N-methylpyrrolyl keto) 2,3-dichlorophenoxy acetic acid with the following chemical formula.

The most preferred compound is 4-[2-(5-methylthienyl) keto] 2,3-dichlorophenoxy acetic acid. The preferred compound has the following chemical formula.

When R is an oxyacetic acid residue, R ¹ can be, of course, any of the R ¹ moieties of general formula I. Representative compounds of general formula I that are oxyacetic acid molecules include:

a'--co}i

CH-.COH

All of the foregoing compounds in the oxyacetic acid series can be modified as described above in general formula I, by substituting other oxyacetic acid residues. The following modifications are representative. R equals:

OCH ₂ CO ₂ C ₂ H ₅ OCH ₂ CO ₂ (CH ₂ ) ₂ ^N(C ₂ H ₅ ) ₂ OCH ₂ CONH(CH ₂ ) ₂ N(CH ₂ ) ₂

Exemplary molecules include:

Where R is an α-methylacetic acid residue, R ¹ can be any of the R ¹ moieties of general formula I, including for example those R ¹ moieties shown in the oxyacetic acid series above. Exemplary molecules in the α-methylacetic acid series include:

Where R is an acetic acid residue, R ¹ can be any of the R ¹ moieties of general formula I, including those R ¹ moieties shown in the oxyacetic acid series above. Exemplary molecules in the acetic acid residue series include:

The invention is useful whenever it is desirable to reduce intraocular pressure or inhibit or prevent intraocular pressure increases. This includes treatment of existing chronic and acute conditions, as well as prophylactic treatment to prevent such conditions. The formulations of the invention may be administered topically to the eye, instilled in the eye or injected intracamerally

into the eye. The preferred manner of administration is topical.

When administered, the formulations of the invention are applied in ophthalmologically acceptable amounts and in ophthalmologically acceptable solutions. Such amounts and solutions are those that cause no medically unacceptable side-effects when administered to an intraocular chamber of the eye according to the methods described herein. Preferred ophthalmologically acceptable solutions for intracameral delivery are sterile solutions which are iso-osmotic with respect to the fluid in intraocular chambers. Such solutions are non-irritating to the eye and maintain the osmotic stability of the tissues defining the chamber. The osmolality preferably is between about 250 and about 350 mOsm and most preferably about 280-320 mOsm. The solutions also are pH compatible with the environment of the selected intraocular chamber. The pH of the solution preferably is between about 6.5 and about 8.0 and more preferably between about 7.2-7.8. Most preferably the pH is 7.4. The solutions optionally contain particular buffering agents and other factors to support metabolism of the eye tissue. For example, the solution may contain bicarbonate at a concentration of between about 10 and 50 mM. The solution also may contain, for example, glucose and glutathione. The buffer preferably is a phosphate buffer whereby the final phosphate concentration is between about 1 and 5 mM. Other additives include sodium and potassium salts such as sodium and potassium chlorides, sulfates, acetates, citrates, lactates, and gluconates. Calcium and magnesium chlorides also may be added. When administered topically, such preparations may routinely contain ophthalmologically acceptable concentrations of salts, buffering agents, preservatives, thickening agents, chelating agents, wetting agents, and delivery enhancing agents. A delivery enhancing agent is a substance that facilitates the delivery of the therapeutic compound of the invention into the aqueous humor, including substances which increase corneal permeability, such as surfactants, wetting agents, liposomes, DMSO, and agents which mildly disrupt the corneal surface. A wetting agent is a substance which evenly coats the outer corneal surface. A preferred wetting agent is benzalkonium chloride. Other examples of wetting agents include sorbitan esters and polyoxyethylene ethers.

Suitable buffering agents include: acetic acid and a salt (1-2% W/V); citric acid and a salt (1-3% W/V); boric acid and a salt (0.5-2.5% W/V); and phosphoric acid and a salt (0.8-2%

W/V). Suitable preservatives include benzalkonium chloride (0.003-0.03% W/V); chlorobutanol

(0.3-0.9% W/V); parabens (0.01-0.25% W/V) and thimerosal (0.004-0.02% W/V). Suitable chelating agents include edetate disodium (0.01-0.2%) W/V). Suitable thickening agents include hydroxypropyl methylcellulose (0.2-5% W/V); polyvinyl alcohol (0.6-10% W/V); and carboxymethyl cellulose sodium (0.5-1.5%) W/V). The topical preparation may be a solution iso-osmotic with tears. It also can be prepared as a semi-solid dosage form such as a sterile hydrophilic gel base (made of carbomers, sodium alginate, cellulose derivatives, montmorillonite clays, gums and the like) or a sterile oleaginous ointment base (made of, for example, white petrolatum, mineral oil, polyethelene glycols and the like). The formulations of the invention are administered in therapeutically effective amounts.

A therapeutically effective amount is one which causes a medically useful decrease in intraocular pressure or prevents or inhibits to a medically usef l degree an increase in intraocular pressure. Such amounts will depend upon the condition being treated and the condition of the patient and can be determined using no more than routine experimentation. The formulations of the invention are administered in nontoxic amounts with acceptable margins of safety. As used herein, "margin of safety" refers to the ratio of the dosage of the intraocular pressure reducing molecules which causes medically unacceptable side effects, and the dosage which causes a substantial (i.e., medically useful) reduction in intraocular pressure in treating or preventing glaucoma (e.g., in a typical patient with open angle glaucoma). The margin of safety of the formulations must be at least 2.0, and more preferably at least 4.0. It is also important that the molecules not produce, at effective dosages, long-term deleterious changes in the eye.

The formulations of the invention are for treatment of glaucomatous conditions in eyes of mammalian subjects (e.g., humans, dogs and cats). The formulations of the invention may be supplied in different containers and forms. In one embodiment, they will be supplied in the form of a solution in a bottle constructed and arranged to facilitate administration of the solution as eyedrops. Such a bottle may have a dropper tip as the upper part, with a detachable cap which seals the dropper tip when the cap is replaced on the bottle. An alternative bottle may have a separable dropper instrument which is attached to the bottle cap, and which is contained inside the bottle when the cap is replaced.

In another embodiment, the compound is supplied as a lyophilized powder. In these

embodiments, a diluent also can be provided and can include sterile water, organic and inorganic electrolytes, and buffering agents. Examples of inorganic electrolytes include, but are not limited to, the chlorides of sodium, potassium, calcium and magnesium. Suitable buffering agents may include the sodium or potassium salts of boric acid, citric acid, phosphoric acid, acetic acid and 5 the like. The lyophilized powder of the invention may contain, in addition to the active ingredients, other pharmaceutically acceptable inert ingredients such as bulking agents. Suitable bulking agents include mannitol and dextran.

Thus, the components in the lyophilized powder and the vehicle for reconstitution may be adjusted such that the final formulation for injection is compatible with the osmolality and pH of o the aqueous humor. Acceptable osmolality may be in the range of 150 to 400 mOsm/kg, while the pH of the formulation may vary from 4.5 - 7.8.

The compounds of the invention and appropriate solutions for their use may be supplied in suitable containers in the form of kits. These kits may include instructions for use, useful additional implements, and may be supplied in a sterile condition with an impervious protective s covering.

Example 1 The method used to prepare ticrynafen was as follows.

1.0% EY-1 17 fticrvnafen') Ointment: A 150 ml beaker was used to weigh out 11.22 o grams of mineral oil, USP (Fisher). 0.75 grams of ticrynafen (tienilic acid, Sodepharm) was ground with a mortar and pestle and 0.50 grams of the ground powder was slowly added to the mineral oil while stirring with a stir bar. The solution was mixed until a homogenous milky white suspension was formed. 38.37 grams of petrolatum, white USP (Spectrum) was weighed out in a container and heated to 90 °C. The petrolatum was then slowly added to the 5 ticrynafen/mineral oil suspension and the resultant suspension was mixed with a homogenizer and allowed to cool to 25-35 °C. This ointment (1.0% EY-1 17) can be stored in a sealed tube.

2.0%) EY-1 17 ( ^' ticrynafen ^' ) Ointment: A 150 ml beaker was used to weigh out 11.04 grams of mineral oil, USP (Fisher). 1.5 grams of ticrynafen (tienilic acid, Sodepharm) was ground with a mortar and pestle and 1.00 grams of the ground powder was slowly added to the 0 mineral oil while stirring with a stir bar. The solution was mixed until a homogenous milky white suspension was formed. 37.99 grams of petrolatum, white USP (Spectrum) was weighed

out in a container and heated to 90 °C. The petrolatum was then slowly added to the ticrynafen/mineral oil suspension and the resultant suspension was mixed with a homogenizer and allowed to cool to 25-35 °C. This ointment (2.0%> EY-117) can be stored in a sealed tube.

5 In Vivo Study Results

Three animal studies were conducted.

Study 1 : Various formulations of ticrynafen were tested for efficacy in lowering intraocular pressure (IOP) in ocular normotensive cynomologus monkeys. Six animals were treated with 1.0% EY-117 ointment in one eye, placebo ointment in the contralateral eye, once ιo daily for 7 consecutive days followed by twice daily treatment for an additional 4 days. Each monkey was randomly assigned one experimental and one control eye. Slit lamp examination was done to ensure normal, healthy eyes prior to the experiment. The monkeys were anesthetized with 10 mg/kg ketamine hydrochloride administered intramuscularly. Supplemental anesthesia was administered at a concentration of 5mg/kg at 45 minute intervals. Baseline is intraocular pressure was measured in each eye with a Digilab Pneumotonometer. The monkeys heads were placed in a headholder with eyes directed ceilingward and a one centimeter strip of EY-1 17 was administered to the lower cul de sac of the eye. A placebo was administered to the opposite eye. A 1 centimeter strip of 1% EY-117 contains on the average 131 ug/cm of ticrynafen. After 15 to 20 minutes the excess ointment was wiped away.

2o The monkeys were carefully examined with a slit lamp on days 1, 3, 5, and 11 at 0 and 3 hours and additional pressures were taken with topical 0.5% proparacaine HC1 at 0, 1, and 3 hours. At day 5 the mean±SEM IOP values for treated versus control eyes at 1 and 3 hours were 13.3±1.12 versus 13.0±0.86 and 12.0±0.52 versus 13.0±1.24 mmHg, respectively. On day 1 1 (the fourth day in which doses were administered twice daily) slight but significant reductions in

25 IOP were observed. The mean IOP values for treated versus control eyes at 0 and 3 hours were

13.5±0.81 versus 15.0±1.10 mmHg (P=0.02) and 14.5±0.85 versus 15.8±1.05 mmHg (P=0.07), respectively. No IOP reductions were observed in treated eyes at 1 hour on Day 11.

Results from the slit lamp exams were similar for both EY-117 and control eyes. Mild » superficial punctate keratopathy was observed on Days 3, 5, and 11 and very mild corneal

30 stippling on Day 11 in some eyes treated with either EY-117 or vehicle. Corneal irregularity was observed in one control eye on Days 1 and 3. There were no apparent differences in ocular

irritation between EY-117 and control eyes as examined by slit lamp.

Study 2: Another study was performed to measure the effect of 2.0%> EY-117 ointment on IOP in laser induced glaucomatous monkeys. EY-117 was administered twice daily to both eyes of glaucomatous monkeys for 5 consecutive days. The monkeys were anesthetized with 1-5 s mg/kg of ketamine hydrochloride. A one centimeter strip of 2.0%> EY-117 was administered to the lower cul de sac of the eye. A 1 centimeter strip of 2% EY-117 contains on the average 250ug/cm of ticrynafen. The eye was then held closed for approximately 30 seconds. The excess ointment was not wiped away.

IOP was measured at 0, 0.5, 1, 2, 3, 4, 5, and 6 hours. Slit lamp exams were performed at o 2, 4, and 6 hours each day. There was an effective IOP reduction with EY-117 treatment which increased with each successive day of dosing after the first day of treatment. There was only a slight reduction in IOP observed on Day 2 but large reductions were observed by Day 4 of treatment. Maximum mean IOP reductions on Days 4 and 5 were 7.5 and 9.8 mmHg, respectively. s There was no apparent drug associated irritation, and all eyes opened widely after drug administration.

Results from the slit lamp exams revealed that 3 of 4 eyes were clear on each of the treatment days. One of 4 eyes exhibited mild corneal epithelial edema on Days 1 and 4 and an epithelial defect, 3x4 mm, was noted in the same eye on Day 5 of treatment. o Study 3: Another study was performed to measure the effect of 2.0%> EY-117 ointment administered twice daily on IOP and outflow facility in ocular normotensive cynomolgus monkeys. Six monkeys were treated with 2.0%> EY-117 in one eye and a vehicle control in the contralateral eye, twice daily for 5 consecutive days. EY-117 was administered under the same conditions as described in study 1 and IOP was measured at 0, 1 , and 3 hour timepoints on Day 5 5. Slip lamp exams were also performed on Day 5 at 0 and 3 hours. Outflow facility was measured on Day 5 following the 3 hour IOP measurement.

Slight reductions in IOP were observed on Day 5 of treatment. Mean change in IOP (IOP±SEM) for treated versus control eyes at 0, 1, and 3 hours was -1.5 mmHg ± 0.72, -0.7 mmHg ± 0.49, and -1.0 mmHg ± 0.58, respectively. 0 Outflow facility measurements encompassing 3.5 to 4.5 hours after treatment on Day 5 demonstrated an increase in outflow facility in the EY-117 treated eyes. Outflow facility values

(mean±SEM) for treated versus control eyes were 0.434+0.027 versus 0.349±0.036 ul/miii/πimHg, respectively. Mean difference in outflow facility (treated - control) was 0.086±0.030 (p=0.034) and mean ratio (treated control) was 1.28±0.09 (p=0.02).

Those skilled in the art will be able to recognize or ascertain with no more than routine experimentation, numerous equivalents to the specific products and processes described herein. Such equivalents are considered to be within the scope of the invention and are intended to be covered by the following claims in which we claim: