Background of the InventionThe present invention relates generally to the field of ophthalmology. In particular, the invention relates to the treatment of ocular disorders including visual field loss and glaucoma using a isoquinolinesulfonyl compound, which lowers intraocular pressure (IOP) and produces dilation of ocular blood vessels.
Although the underlying causes of glaucoma are not fully understood at this time, glaucoma is characterized by damage to the optic nerve head, accompanied by a decrease in the normal visual field. One risk factor for glaucomatous visual field loss is elevated IOP. In fact, glaucoma has historically been treated by drug and/or surgical therapy to lower elevated IOP. While elevated IOP has been positively correlated with the rate of progression of visual field loss in glaucoma, visual field loss may occur at levels of IOP which are considered within the normal range. Thus, other factors, alone or in addition to elevated IOP, may influence the occurrence and rate of progression of visual field loss.
To remain healthy and function normally, the retina and the optic nerve head fibers (neurons) must receive a proper supply of nutrients and oxygen, and must have their carbon dioxide and other metabolic waste products removed. This is accomplished by the microcirculation in these tissues. As used herein, the term "microcirculation" refers to the blood flow through the nutritive blood vessels, across whose walls nutrients, gases and waste products move. Blood flow to the eye depends upon the perfusion pressure (the systemic blood pressure minus the IOP). Some tissues have the ability to maintain (i.e., autoregulate) blood flow through a range of perfusion pressures such that an increase in systemic blood pressure may cause a reduction in the caliber of the blood vessel lumen. Conversely, reduction in systemic pressure in such tissues can result in vessel dilation; however, there is a point where perfusion pressure falls to such a level that the vessel is maximally dilated. Any further fall in perfusion pressure results in a reduction of blood flow to the tissue (ischemia). Ischemia may also result from obstruction, vasospasm, increased vascular resistance, or other interference with microcirculation. Prolonged ischemia ultimately can result in tissue necrosis or neuronal cellular apoptosis. In the case of the optic nerve head or retina, a state of visual dysfunction may precede the death of the neurons. Hence, if ischemia is involved in the death of optic nerve fibers due to glaucoma or some other ischemic-borne retinopathies or optic neuropathies, then its prevention could protect the neurons from death or loss of function.
The vasodilatory and spasmolytic activities of certain isoquinolinesulfonyl compounds have been described with respect to non-ocular tissues. See, e.g., EP 0 187 371 B1, which corresponds to U.S. Patent No. 4,678,783. These vascular attributes are likely associated with inhibition of myosin-light chain kinase activity. Myosin-light chain kinase is an enzyme necessary for the excitation-contraction coupling of contractile activity in vascular smooth muscle. Inhibition of this enzyme results in vascular smooth muscle relaxation (i.e., vasodilation) which can produce an increased blood flow.
WO93/23082 discloses topical ophthalmic compositions useful in the treatment of glaucoma and ocular hypertension. The compositions contain a combination of at least one calcium channel antagonist to prevent or reduce the loss of visual field and at least one compound which lower intraocular pressure to maintain intraocular pressure at normal levels. JP-A-07 277 979 discloses substituted isoquinoline-sulphonamide derivatives which are useful for treating and preventing cardiovascular symptoms, eye symptoms, haemophilia, and nerve symptoms due to blood viscosity increase.
WO95/15958 discloses compounds having potent calcium antagonist and antioxidant activity. The compounds and associated pharmaceutical compositions disclosed are useful to prevent or alleviate damage to various types of tissue, in particular ophthalmic tissue.
Summary of the InventionThe inventors believe that microcirculatory disturbances that restrict nutritive blood flow to the choroid, retina and optic nerve head are likely involved in the progression of visual field loss. While bound by no theories, the inventors postulate that compounds which enhance oxygen and nutrient delivery by enhancing ocular blood flow may be beneficial in preventing optic nerve head injury and may subsequently prevent or alter the rate of progression of visual field loss associated with glaucoma and ischemic optic neuropathies.
The present invention provides topical ophthalmic compositions as defined in claim 1 for the treatment of glaucoma (with or without ocular hypertension) and ocular ischemia, which may result in retinopathies and optic neuropathies. These compositions are effective in reducing or preventing optic nerve head or retinal damage as well as reducing IOP toward normal levels and thus, in reducing or preventing visual field loss.
The invention also provides the use of compositions, as defined hereinafter, in the manufacture of medicaments for treating glaucoma, ocular hypertension, ocular ischemic and related disorders in a patient with one or more of such conditions. The glaucoma (which may occur with or without ocular hypertension) and ocular ischemia may result in retinopathies and optic neuropathies.
In an alternative embodiment of the compositions and uses of the present invention, the above compositions may further include a mucomimetic polymer, a gelling polysaccharide, a finely divided drug carrier substrate (defined below), or a combination of these components. These additional components provide compositions which enhance comfort and provide sustained release and delivery of the drug to the eye.
Detailed Description of the InventionElevation of IOP is associated with clinical manifestations characteristic of glaucomatous optic neuropathy. Optic nerve dysfunction may be the result of pressure-induced changes in the structure of the optic nerve head and/or reduced circulation to the optic nerve head and retina. In addition to affecting vascular resistence and blood flow, the inventors have discovered that certain isoquinolinesulfonyl compounds also lower intraocular pressure.
The compositions employed in the uses of the present invention include, as the sole therapeutically active ingredient, an opthalmically effective amount of an isoquinolinesulfonyl compound of formula (I) shown below, as well as their pharmaceutically acceptable salts. wherein
- R1
- represents a hydrogen atom, a chlorine atom or a hydroxyl group; and when R1 represents a hydrogen atom,
- A
- represents an ethylene group unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a benzyl group,
- R2 and R3
- are directly bonded with each other, thereby forming a trimethylene group unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a benzyl group, and
- R4
- represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; and
when
- R1
- represents a chlorine atom or a hydroxyl group,
- A
- represents an alkylene group having 2 to 6 carbon atoms, said group being unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms,
- R2 and R3
- are not bonded with each other and each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, or R2 and R3 are directly bonded with each other, thereby forming an ethylene group unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms or a trimethylene group unsubstituted or substituted with alkyl group having 1 to 6 carbon atoms, and
- R4
- represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an amidino group;
and pharmaceutically acceptable salts thereof. Alternatively, where the compound of formula (I) is not the sole therapeutically active ingredient, the compound of formula (II) as defined hereinafter is excluded. With respect to the above-mentioned alkyl groups, they may be a straight chain group or a branched chain group. These compounds and methods of their syntheses are disclosed in U.S. Patent No 4,678,783, the entire contents of which are incorporated herein by this reference. Other isoquinolinesulfonyl derivatives and methods of their syntheses are disclosed in U.S. Patent No. 4,525,589, the entire contents of which are likewise incorporated herein by this reference.
The preferred isoquinolinesulfonyl compound employed in the various embodiments of the present invention is hexahydro-1-(5-isoquinolinylsulfonyl)-1H-1,4-diazepine, also known as1-(5-isoquinolinesulfouyl)-homopiperazine, and shown below as Compound (II), as well as its pharmaceutically acceptable salts. Most preferred is the hydrochloride salt of Compound (II). The hydrochloride salt of Compound (II), known as fasudil, AT-877, and HA-1077 is manufactured by Asahi Chemical Industry Co., Ltd. (Japan).
Alternatively, Compound (II) and a preferred metabolite thereof may be represented by the following formula: wherein R = H or OH.
In general, for topical administration an amount of an isoquinolinesulfonyl compound between 0.001 and 10.0 percent by weight (wt%) is used in the compositions of the present invention. It is preferred that between 0.01 and 3.0 wt% is used, and it is especially preferred to use an amount between 0.1 and 2.0 wt%.
The compositions of the present invention may additionally include components to provide sustained release and/or comfort. Such components include mucomimetic polymers, gelling polysaccharides and finely-divided drug carrier substrates. These components are discussed in greater detail in U.S. Patent No. 4,911,920 issued March 27, 1990 and in U.S. Patent No. 5,212,162 issued May 18, 1993. The entire contents of these two patents are incorporated herein by reference. For purposes of this invention, the term "mucomimetic polymers" includes carbomers (discussed below), mucopolysaccharides (e.g. hyahironic acid and chondroitin sulfate) and cellulosic polymers (e.g. methyl cellulose, hydroxy propyl methyl cellulose, hydroxyethyl cellulose, carboxy methyl cellulose, and hydroxy propyl cellulose).
The preferred mucomimetic polymers useful in the present invention are anionic and have a molecular weight between about 50,000 and 6 million daltons. These preferred polymers are characterized as having carboxylic acid functional groups and preferably contain between 2 and 7 carbon atoms per functional group. The gels which form during preparation of the ophthalmic polymer dispersion have a viscosity between about 1,000 to about 300,000 centipoise (cps). Suitable polymers are carboxy vinyl polymers, preferably those called carbomers, e.g., CARBOPOL® (Goodrich Co., Cleveland, Ohio). Specifically preferred are CARBOPOL® 934 and 940. Such polymers will typically be employed in an amount between about 0.05 and about 8.0 wt%, depending on the desired viscosity of the composition. Pourable liquid compositions generally comprise an amount of the polymer between 0.05 and 2.0 wt%.
As used herein, the term "finely-divided drug carrier substrate" (or "DCS") means finely-divided solids, colloidal particles, or soluble polymers and/or polyelectrolytes which are capable of selective adsorption or binding with drug molecules. Examples of DCS include, but are not limited to: finely divided silica, such as fumed silica, silicates and bentonites; ion exchange resins, which can be anionic, cationic or non-ionic in nature; and soluble polymers, such as, alginic acid, pectin, soluble carrageenans, CARBOPOL®, and polystyrene sulfonic acid. In general, the DCS component is used at a level in the range of 0.05 to 10.0 wt%. For particulate DCS, the average particle size diameter ranges from 1 to 20 µm. The amount of DCS and its characteristics (e.g., amount of cross-linking, particle size) may be varied in order to produce the desired time-release profile for the chosen drug.
Preferred DCS are the ion exchange resins. Some resins which are used in chromatography make ideal DCS for binding drugs in the compositions of the present invention. Such resins are readily available, for example, from Rohm & Haas (Philadelphia, Pennsylvania) under the name AMBERLITE® and from Dow Chemical Co. (Midland, Michigan) under the name DOWEX®. The average particle size diameter of the commercially available forms of the resins is 40 to 150 µm. Such commercially available particles are most conveniently reduced to a particle size range of 1.0 to 25 µm by ball milling, according to known techniques. At least 95% of the resulting spheroidal particles will preferably have a diameter less than 20 µm. The ion exchange resins will typically be present in an amount between 0.05 and 10.0 wt% and will have an average particle size diameter between 1 and 20 µm.
In addition to the above-described principal ingredients, the compositions of the present invention may further comprise various formulatory ingredients, such as antimicrobial preservatives and tonicity agents. Examples of suitable antimicrobial preservatives include: benzalkonium chloride, thimerosal, chlorobutanol, methyl paraben, propyl paraben, phenylethyl alcohol, edetate disodium, sorbic acid, polyquaternium 1 and other agents equally well-known to those skilled in the art. Such preservatives, if utilized, will typically be employed in an amount between 0.001 and 1.0 wt%. Examples of suitable agents which may be utilized to adjust the tonicity or osmolality of the formulations include: sodium chloride, potassium chloride, mannitol, dextrose, glycerin and propylene glycol. Such agents, if utilized, will typically be employed in an amount between 0.1 and 10.0 wt%.
As will be appreciated by those skilled in the art, the compositions may be formulated in various dosage forms suitable for topical ophthalmic delivery, including solutions, suspensions, emulsions, gels and erodible solid ocular inserts. The compositions are preferably aqueous, have a pH between 3.5 and 8.0 and an osmolality between 280 and 320 milliOsmoles per kilogram (mOsm/kg).
The compositions of the present invention may also comprise non-aqueous formulations such as: substantially non-aqueous liquids, substantially non-aqueous semi-solid compositions, and solid compositions or devices. The first class, substantially non-aqueous liquids, includes a isoquinolinesulfonyl compound dissolved or suspended in one or more of the following: vegetable and mineral oils, such as liquid petrolatum, com oil, castor oil, sesame oil, and peanut oil; triglycerides, such as the capric/caprylic triglycerides commonly used in foods and cosmetics; liquid lanolin and lanolin derivatives; and perfluorohydrocarbons. The second class, semi-solid compositions, comprises an isoquinolinesutfonyl compound dissolved or suspended in one or more of the following: various types of petrolatum, such as white, yellow, red, and so on; lanolin and lanolin derivatives; gelled mineral oil having a hydrocarbon base, such as PLASTIBASE®; petrolatum and ethylene carbonate mixtures; petrolatum in combination with surfactants and polyglycol, such as polyoxyl 40 stearate and polyethylene glycol.
The third class, solid compositions or devices, includes an isoquinolinesulfonyl compound in association with (i) non-erodible devices which are inserted into the conjunctival sac of the eye and later removed, such as the Alza-type diffusion or osmotic pressure controlled polymer membranes; and (ii) bioerodible polymers which do not have to be removed from the conjunctival sac, such as essentially anhydrous but water soluble polymers and resins (e.g., celluloses, polycarboxylic acids, and so on). Especially preferred are the bioerodible inserts described and detailed in U.S. 4,540,408 (Lloyd) and U.S. 4,730,013 (Bondi et al.), wherein isoquinolinesulfonyl compounds of the present invention would be entrained in a non-aqueous matrix consisting essentially of polyvinyl alcohol. The entire contents of these two patents are incorporated herein by reference.
As will further be appreciated by those skilled in the art, the medicaments manufactured in accordance with the use of the present invention may also be administered intraocularly, periocularly or systemically (e.g. parenterally or orally).
Intraocular or periocular administration may be effected by incorporating a isoquinolinesulfonyl compound in a surgical irrigating solution used in ophthalmic surgery, or, preferably, by intravitreal or periocular injection. Such injection therapy will typically require from 0.1 nM to 1mM (approximately 0.02ng to 500µg) of a isoquinolinesulfonyl compound for each eye treated. It is preferred that between 200nM and 160µM (approximately 40ng to 80µg) per eye be used in such therapy.
The preferred routes of systemic administration are oral and intravenous. Oral dosing of an isoquinolinesulfonyl compound in accordance with this invention will typically range from 1.0 to 1000 mg, one to four times per day. The preferred dosing range of oral administration is from 10 to 250 mg two to three times per day. Intravenous dosing of an isoquinolinesulfonyl compound in accordance with this invention will typically range from 0.01 to 100 mg, one to four times per day. The preferred dosing range for intravenous administration is from 1.0 to 30 mg, two to three times per day.
The compositions of the present invention are useful in methods of treating glaucoma and other ophthalmic diseases and abnormalities associated with visual field loss. The treatment may be effected by administering a therapeutically effective amount of an isoquinolinesulfonyl compound topically, intraocularly, periocularly or systemically. The preferred methods comprise topically applying to the affected eye(s) of the patient a therapeutically effective amount of a composition according to the present invention. The frequency and amount of dosage will be determined by the clinician based on various clinical factors. The preferred methods will typically comprise topical application of one or two drops (or an equivalent amount of a solid or semi-solid dosage form) to the affected eye as needed, preferably one to three times per day.
The following examples are presented to further illustrate various aspects of the present invention.
Example 1The hydrochloride salt of Compound II, also known as fasudil hydrochloride or just fasudil, was topically administered to eyes of ocular hypertensive monkeys, New Zealand Albino (NZA) and Dutch Belted (DB) rabbits. The results are presented in Table 1. As presented, Compound II effectively lowered IOP in both ocular normotensive and hypotensive (laser-induced) primates. In NZA rabbits, IOP was marketedly lowered below base line for the four hour dose response. Compound II also lowered IOP in the DB rabbit; however, the reduction in IOP was not sustained as in the NZA rabbit study.
Table 1. |
| | |
| | 1 HR | 2 HR | 3 HR | 4 HR | 6 HR |
| Lasered MIOP(n=9) † | 32.1±3.2 | 21.9±6.7 ↓ | - - | 14.6±6.5 ↓ | - - | 23.4±4.4 ↓ |
| Lasered MIOP(n=9) | 38.2±3.3 | 15.9±6.8 ↓ | - - | 16.1±4.8 ↓ | - - | 7.1±4.9 ↓ |
| Normal MIOP(n=9) | 20.4±1.4 | 18.9±5.5 ↓ | - - | 21.7±5.2 ↓ | - - | 11.1±5.3 ↓ |
| Dutch Betted Rabbit(n=7) †† | 37.4±0.6 | 33.7±2.1 ↓ | 18.0±3.7 ↓ | 10.8±5.2 ↓ | 6.6±3.9 ↓ | - - |
| Dutch Belted Rabbit(n=7) †† | 32.1±0.4 | 33.1±2.7 ↓ | 25.2±3.5 ↓ | 16.7±3.9 ↓ | 11.7±4.0 ↓ | - - |
| NZA Rabbit(n=7) †† | 27.2±0.3 | 36.2±3.7 ↓ | 35.5↓3.6 ↓ | 26.1±3.9 ↓ | 22.5±3.8 ↓ | - - |
| All drugs were administered to eyes in a topical manner at a dose = 500 µg (2x25 µl). Fasudil was formulated in phosphate buffered saline containing 0.01% benzalkonium chloride.† No significant change in tOP from baseline values was observed in the contralateral untreated ocular normotensive eye or in a vehicle treated ocular hypertensive eye. †† No significant change in IOP from baseline values were observed in the contralateral untreated eye.MIOP = monkey intraocular pressure, n = number of animals in study |
Compound II (hydrochloride) was administered topically to the eyes of Dutch Belted (DB) rabbits in doses of 75 and 154µg. The results are presented in Table 2.
Table 2. |
| | |
| | | | | | |
| Group 1Fasudil150 µg OD | 33.0±0.8 | 8.8±3.8 ↓ | 11.5±3.2 ↓ | 14.6±3.5 ↓ | 3.4±2.7 ↓ | 0.5±3.2 ↑ |
| Group 1VehicleOS | 33.8±0.6 | 3.3±1.9 ↓ | 3.7±2.4 ↓ | 5.7±2.6 ↓ | 0±2.4 ↓ | 2.1±3.2 ↑ |
| Group 2Fasudil75 µg OD | 34.3±0.8 | 3.2±2.8 ↓ | 3.3±1.9 ↓ | 1.7±2.7 ↓ | 5.2±2.2 ↓ | 2.9±2.1 ↓ |
| Group 2VehicleOS | 33.8±0.6 | 1.1±0.6 ↑ | 5.9±2.6 ↑ | 6.0±3.9 ↑ | 4.5±1.9 ↑ | 1.9±3.4 ↑ |
| All drugs were administered to eyes in a topical manner (1x30 µl). All compounds were formulated in a phosphate buttered saline containing 0 01% benzalkonium chloride. N=6 animals/group: OD= drug treated eye: OS=vehicle treated contralateral eye. |
A dose study similar to that described in Example 2 was conducted with the NZA rabbit. Compound II (hydrochloride) was administered in a topical ocular fashion in doses of 50, 125 and 250µg. The results of this study are presented in Table 3.
Table 3. |
| | |
| | | | | | |
| Group 1Fasudil250 µg OD | 20.6±0.3 | 5.5±6.7 ↓ | 21.1±5.4 ↓ | 24.9±6.1 ↓ | 25.1±4.1 ↓ | 16.3±4.0 ↓ |
| Group 2VehicleOS | 21.2±.5 | 1.1±3.7 ↓ | 4.4±3.4 ↑ | 2.7±3.2 ↑ | 2.7±3.9 ↑ | 5.4±3.6 ↑ |
| Group 2Fasudil125 µg OD | 20.4±.7 | 2.8±3.8 ↑ | 11.6±2.9 ↓ | 11.0±4.7 ↓ | 7.0±4.8 ↓ | 5.1±2.7 ↓ |
| Group 2VehicleOS | 21.3±.6 | 5.3±2.6 ↑ | 8.3±6.0 ↑ | 7.3±4.6 ↑ | 7.2±5.3 ↑ | 17.1±6.5 ↑ |
| Group 3Fasudil50 µg | 21.3±.5 | 1.6±3.0 ↓ | 3.2±3.1 ↑ | 2.1±4.7 ↑ | 1.7±4.3 ↓ | 10.8±5.7 ↑ |
| Group 3VehicleOS | 21.4±.8 | 6.7±4.1 ↑ | 9.1±1.7 ↑ | 3.6±3.3 ↑ | 9.8±7.6 ↑ | 7.4±4.5 ↑ |
| All drugs were administered to eyes in a topical manner (1x30 µl). All compounds were formulated in a phosphate buttered saline containing 0.01% benzalkonium chloride. N=6 animals/group: OD= drug treated eye: OS=vehicle treated contralateral eye. |
The effect of repeated doses of Compound II on the magnitude and duration of IOP reduction was evaluated in ocular normotensive monkeys. As shown in Table 4, a total of 900µg of Compound II (hydrochloride) administered in three doses, ten minutes apart, resulted in significant IOP reduction.
Table 4. |
| | |
| | | | |
| Fasudil900 µg OS | 20.6±0.8 | 23.1±2.8 ↓ | 23.1±3.3 ↓ | 19.3±3.2 ↓ |
| Vehicle 3 x 30 µlOS | 20.2±0.8 | 4.1±1.8 ↓ | 0.3±4.4 T | 1.1±3.7 ↓ |
| Fasudil was administered 3 x 30 µl topically (1 x 30 µl. 10 minutes apart). N=10 for drug treated and N=5 for vehicle. Fasudil was formulated in a phosphate buttered saline containing 0.01% benzalkonium chloride. |
| Ingredient | % (w/v) |
| Compound II (hydrochloride) | 1.5 |
| Benzalkonium chloride | 0.01 |
| Phosphate buffered saline | q.s. to 100 |
| Ingredient | % (w/v) |
| Compound II (hydrochloride) | 1.0 |
| Carbomer 934P or Carbomer 974P | 0.5 |
| NaCl | 0.4 |
| Mannitol | 2.4 |
| Disodium edetate | 0.01 |
| BAC | 0.01 |
| Water for Injection | q.s. to 100 |
| NaOH or HCl to adjust pH | q.s. |
| Ingredient | Weight Proportion |
| Compound II (hydrochloride) | 50 |
| Sodium Citrate | 20 |
| Alginic Acid | 5 |
| Polyvinylpyrrolidone | 15 |
| Magnesium Stearate | 5 |
Preparation: The dry composition is thoroughly blended, tablets are punched from the resulting mixture, each tablet being of such size that it contains 10mg of Compound II (hydrochloride).
| Ingredient | % (w/v) |
| Compound II (hydrochloride) | 0.002 |
| Sterile balanced salt solution | q.s. to 100 |
A patient suffering from elevated TOP and/or visual field loss is treated by the topical administration of the formulation of Example 5. One 30µl drop of the formulation is administered one to four times per day to the affected eye(s) thereby reducing the TOP and/or the progression of visual field loss.
Example 10Method of Treatment (Systemic)A patient suffering from elevated TOP and/or visual field loss is treated by the oral administration of the formulation of Example 7. One or more tablets of the formulation are administered orally 1 to 4 times per day thereby reducing the IOP and/or the progression of visual field loss.
Example 11Method of Treatment (Intraocular or Periocular)A patient suffering from elevated IOP and/or visual field loss is treated by the intravitreal or periocular administration of the formulation of Example 8. Ten to twenty-five microliters of the formulation are administered 1 time per month to the affected eye(s) thereby reducing the IOP and/or the progression of visual field loss.
Example 12Other isoquinolinesulfonamiades were topically administered to the eyes of New Zealand Albino (NZA) rabbits. The results are presented in Table 5 below. All drugs were administered to eyes in a topical manner at a dose = 500 µg (2x25 µl). All compounds were formulated in phosphate buffered saline containing 0.01% benzalkonium chloride, and in all instances N = 7.