Eye drops containing ultrafine, poorly water-soluble drugs and water-soluble drugs, and methods for producing and using the same

Abstract

To provide an eye drop that contains a water-insoluble drug and a water-soluble drug while retaining a homogeneous suspension state and a method for producing the same.SOLUTION: The present invention discloses an eye drop that contains a nano water-insoluble drug and a water-soluble drug and forms a homogeneous suspension on day 7 after left standing; and a method for producing an eye drop that includes the steps of: subjecting a water-insoluble drug to hyperfining treatment, to give a nano water-insoluble drug; and mixing the nano water-insoluble drug with a water-soluble drug, to give an eye drop containing the nano water-insoluble drug and the water-soluble drug.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an eye drop comprising a mixture of an ultrafine, poorly water-soluble drug and a water-soluble drug; a method for producing an eye drop comprising mixing an ultrafine, poorly water-soluble drug and a water-soluble drug; and a method for improving the corneal permeability of a poorly water-soluble drug and a water-soluble drug by using an eye drop comprising an ultrafine, poorly water-soluble drug and a water-soluble drug. [Background technology]

[0002] Eye diseases such as cataracts and glaucoma are treated with multiple drugs in combination. In addition, when surgery is performed for eye diseases such as cataracts and retinal diseases, multiple types of eye drops are generally used for postoperative management, each containing an antibacterial drug and an anti-inflammatory drug.

[0003] When eye drops are used to treat and prevent eye diseases, the eye drops are applied several times a day, and the more types of eye drops used, the more frequent the application, which places a burden on patients. In particular, most patients with eye diseases such as cataracts and glaucoma are elderly by nature, and the increased burden of applying eye drops leads to a problem of decreased adherence to eye drops (voluntary compliance with treatment).

[0004] In order to reduce the burden on patients and the frequency of eye drops, eye drops containing a mixture of multiple drugs have been considered. However, some drugs are water-soluble and some are poorly soluble in water. When a poorly water-soluble drug is used, the eye drop is in a suspension state, and it is difficult to make it into a uniform solution, which tends to reduce the dispersion stability of the drug. As a method for increasing the dispersion stability or solubilization rate of a drug in an eye drop containing a poorly water-soluble drug, there are methods described in Patent Document 1 and Non-Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2020-534321 [Non-patent literature]

[0006] [Non-Patent Document 1] Noriaki Nagai et al., Toxicology, 319 (2014), pp.53-62 Summary of the Invention [Problem to be solved by the invention]

[0007] However, little is known so far about a method for making the entire solution into a homogeneous suspension when it contains not only a poorly water-soluble drug but also a combination of a poorly water-soluble drug and a water-soluble drug, and about an eye drop that maintains the dispersion stability of the poorly water-soluble drug and the water-soluble drug.

[0008] Therefore, an object of the present invention is to provide an eye drop that contains a poorly water-soluble drug and a water-soluble drug and maintains a homogeneous suspension state, and a method for producing the same. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors have focused on the miscibility of poorly water-soluble drugs and water-soluble drugs, and have found that ultrafine particle size reduction of poorly water-soluble drugs is a possible way to improve the miscibility. In this case, by ultrafine particle size reduction of poorly water-soluble drugs in the presence of an inclusion compound, aggregation between poorly water-soluble drugs and the associated precipitation can be suppressed. Based on this finding, the present inventors have succeeded in producing an eye drop containing ultrafine particle size reduction of poorly water-soluble drugs and water-soluble drugs.

[0010] Moreover, it was surprisingly found that when the obtained eye drops were instilled into the eye, the corneal permeability could be improved not only for poorly water-soluble drugs but also for water-soluble drugs. Based on such findings, the present inventors have succeeded in creating an eye drop containing ultrafinely divided poorly water-soluble drugs and water-soluble drugs, which can solve the problems of the present invention. The present invention has been completed based on such findings and successful examples.

[0011] That is, according to the present invention, there are provided eye drops and methods according to the following aspects: [1] An eye drop preparation which contains a nanosized poorly water-soluble drug and a water-soluble drug, and which is a homogeneous suspension after being left to stand for 7 days. [2] The eye drop according to [1], wherein the nanosized poorly water-soluble drug has an average particle size of 10 nm to 400 nm. [3] The eye drop preparation according to any one of [1] to [2], further comprising a suspending auxiliary clathrate compound. [4] The eye drop preparation according to [3], wherein the suspending aid is at least one suspending aid selected from the group consisting of inclusion compounds, surfactants, sugars, sugar alcohols, water-soluble polymers, and amino acids. [5] The eye drop preparation according to [4], wherein the inclusion compound is at least one cyclodextrin selected from the group consisting of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin, and methyl-β-cyclodextrin. [6] A step of obtaining a nano-sized poorly water-soluble drug by subjecting a poorly water-soluble drug to ultrafine processing; A step of obtaining an eye drop containing the nanosized poorly water-soluble drug and the water-soluble drug by mixing the nanosized poorly water-soluble drug and the water-soluble drug. A method for producing an eye drop comprising the steps of: [7] The method according to [6], wherein the ultrafine-pulverizing treatment is performed in the presence of a suspension auxiliary. [8] A method for improving the corneal permeability of a poorly water-soluble drug and a water-soluble drug, comprising a step of contacting the cornea with an eye drop containing a nanosized poorly water-soluble drug and a water-soluble drug, thereby improving the corneal permeability of the water-soluble drug and the water-soluble drug compared to contacting the cornea with an eye drop containing a non-nanosized poorly water-soluble drug and a water-soluble drug. Effect of the Invention

[0012] According to an embodiment of the present invention, the eye drop contains an ultrafinely divided poorly water-soluble drug and a water-soluble drug, so that the dispersion stability of the drug is high and a homogeneous suspension state can be maintained. In addition, according to the present invention, the permeability to the cornea of ​​both the poorly water-soluble drug and the water-soluble drug can be increased, and the pharmacological action of the drug can be effectively applied to the ocular tissue, which is expected to treat and prevent eye diseases such as cataracts and glaucoma, which are the targets of the drug. [Brief description of the drawings]

[0013] [Figure 1] As described in the examples below, Figure 1A shows the average particle size of commercially available fluorometholone bulk powder measured by laser scattering method; Figure 1B shows the average particle size of nanoized fluorometholone measured by laser scattering method; Figure 1C shows the average particle size of nanoized fluorometholone measured by nanotracking method; and Figure 1D is an image of nanoized fluorometholone particles taken with a scanning probe microscope. [Diagram 2] As described in the Examples below, Fig. 2A shows the results of measuring fluorometholone concentration over time; Fig. 2B shows the results of measuring rebamipide concentration over time; Fig. 2C is a photograph of a glass tube containing the test mixed eye drops; Fig. 2D is a diagram showing the number of nanosized fluorometholone particles with an average particle size of 1 μm or less in the mixed eye drops FBL-NPs 0 days and 1 month after standing. In the figures, "*1" indicates P<0.05 vs. CA-FL, and "*2" indicates P<0.05 vs. FBL-MPs. [Diagram 3] FIG. 3 is a schematic diagram of an apparatus used to evaluate the in vitro corneal permeability of a poorly water-soluble drug (fluorometholone) in a test mixed eye drop, as described in the Examples below. [Figure 4] FIG. 4 shows the results of evaluation of in vitro corneal permeability of a poorly water-soluble drug (fluorometholone) in a test mixed eye drop, as described in the Examples below. [Diagram 5]FIG. 5 is a schematic diagram of a test system for evaluating the in vivo corneal permeability of a poorly water-soluble drug and a water-soluble drug in a test mixed eye drop, as described in the Examples below. [Figure 6] Figure 6 is a graph showing the results of evaluation of in vivo corneal permeability of a poorly water-soluble drug (fluorometholone) in the test mixed eye drop, as described in the examples below; Figure 6A shows the results of evaluation of in vivo corneal permeability of a water-soluble drug (levofloxacin) in the test mixed eye drop, and Figure 6C shows the results of evaluation of in vivo corneal permeability of a water-soluble drug (bromfenac sodium) in the test mixed eye drop. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Each aspect of the present invention will be described in detail below, but the present invention is not limited to the details of these items and can take various forms as long as the object of the present invention is achieved.

[0015] Unless otherwise specified, each term in this specification is used in the sense commonly used by those skilled in the art in the industry of pharmaceuticals including eye drops, and should not be interpreted as having an unduly restrictive meaning. In addition, the speculations and theories made in this specification are based on the knowledge and experience of the inventors, and therefore the present invention is not limited solely to such speculations and theories.

[0016] "Content" is synonymous with concentration and refers to the ratio of the amount of a component to the total amount of a solution. However, the total amount of the content of the components does not exceed 100%. In this specification, unless otherwise specified, the unit of content means "mass% (wt%)". When a commercially available product is used, the content of the component is preferably the amount of the component contained in the commercially available product, but may be the amount of the commercially available product itself. The term "and / or" means any one or any or all combinations of two or more of the associated listed items. In a numerical range, "to" means a range that includes the numerical values ​​before and after it, for example, "0% to 100%" means a range that is equal to or greater than 0% and equal to or less than 100%. "More than" and "less than" mean a lower limit and an upper limit, respectively, without including the numerical value before it, for example, "more than 1" means a numerical value greater than 1, and "less than 100" means a numerical value less than 100. "Comprising" means that elements other than the elements explicitly stated as being included can be added (same meaning as "comprising at least"), but also encompasses "consisting of" and "consisting essentially of." In other words, "comprising" can mean including the elements explicitly stated and any one or more elements, consisting of the elements explicitly stated, or consisting essentially of the elements explicitly stated. Elements include limitations such as ingredients, steps, conditions, and parameters.

[0017] The eye drop preparation of one embodiment of the present invention contains a nanosized poorly water-soluble drug and a water-soluble drug. The eye drop preparation of one embodiment of the present invention is a homogenous suspension after being left standing for 7 days.

[0018] A nano-sized poorly water-soluble drug is a poorly water-soluble drug with an average particle size of less than 1 μm (nano level). A poorly water-soluble drug is a compound that is classified as "hardly soluble (solvent volume required to dissolve 1 g or 1 mL of solute is 100 mL or more) to "hardly soluble (solvent volume required to dissolve 1 g or 1 mL of solute is 10,000 mL or more)" according to the solubility measurement method specified in the Japanese Pharmacopoeia. In contrast, a water-soluble drug is a compound that is classified as "very soluble (less than 1 mL) to "slightly soluble (less than 100 mL)" according to the solubility measurement method specified in the Japanese Pharmacopoeia. The solubility is the degree to which a drug dissolves within 30 minutes after powdering it and placing it in water and shaking vigorously for 30 seconds every 5 minutes at 20±5°C according to the Japanese Pharmacopoeia No. 17.

[0019] The poorly water-soluble drug and the water-soluble drug may be either one produced by a known method or one commercially available, so long as they are used as the active ingredient of the eye drop. Non-limiting examples of poorly water-soluble drugs include fluorometholone, rebamipide, indomethacin, brinzolamide, triamcinolone acetonide, pirenoxine, brinzolamide, latanoprost, isopropyl unoprostone, etc. Non-limiting examples of water-soluble drugs include bromfenac sodium, levofloxacin, timolol maleate, etc. The poorly water-soluble drug and the water-soluble drug may be one of the above-mentioned drugs alone or two or more of them in combination.

[0020] If the poorly water-soluble drug manufactured or commercially available is at the nano level, it can be used as a nano-sized poorly water-soluble drug. On the other hand, the average particle size of typical commercially available poorly water-soluble drugs is 1 μm or more (micro-level). Therefore, when the poorly water-soluble drug is at the micro-level, the poorly water-soluble drug is subjected to ultrafine processing to obtain a nano-sized poorly water-soluble drug.

[0021] The ultrafine processing of the poorly water-soluble drug is not particularly limited as long as it does not significantly affect the pharmacological action of the poorly water-soluble drug, and examples thereof include a physical grinding process using a device such as a nano-pulverizer, a process of repeatedly crushing with a bead mill using metal beads and centrifuging, etc. The ultrafine processing may be either a dry grinding process in which a powder of the poorly water-soluble drug and a powder of an optional component are added to a grinding container and ground, or a wet grinding process in which such grinding is carried out in the presence of water, but a wet grinding process is preferred in order to improve the mixing of the poorly water-soluble drug with water-soluble components such as the water-soluble drug.

[0022] In addition, when performing ultrafine processing of a poorly water-soluble drug, it is preferable to add a suspension aid. By adding a suspension aid, the dispersibility of the poorly water-soluble drug in the suspension can be improved. When a poorly water-soluble drug is subjected to ultrafine processing by wet grinding, it is preferable to add the poorly water-soluble drug to an aqueous solution containing a suspension aid and then subject it to wet grinding.

[0023] The suspension aid is not particularly limited as long as it improves the dispersibility of a poorly water-soluble drug in an aqueous solution, and examples thereof include inclusion compounds such as α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin, and methyl-β-cyclodextrin; surfactants such as docusate sodium, benzalkonium chloride, and sodium lauryl sulfate; water-soluble polymers such as carboxyvinyl polymers, hydroxyethyl cellulose, hydroxypropyl methylcellulose, methylcellulose, hydroxypropyl cellulose, alginic acid and its salts, polyvinyl alcohol, polyvinylpyrrolidone, macrogol, chondroitin sulfate and its salts, and hyaluronic acid and its salts; and amino acids such as glycine, leucine, and isoleucine. The suspension aid may be either one produced by a known method or a commercially available one. In addition, the suspension aid may be one of the above-mentioned ones alone or two or more of them in combination.

[0024] Among the above-mentioned suspension aids, inclusion compounds are more preferable, and 2-hydroxypropyl-β-cyclodextrin is even more preferable, because they can disperse poorly water-soluble drugs better in the eye drops. When an inclusion compound such as 2-hydroxypropyl-β-cyclodextrin is used, the nano-sized poorly water-soluble drug is included in the inclusion compound, and aggregation between the poorly water-soluble drug and the water-soluble drug and any component in the eye drops, sedimentation caused by the aggregation, etc. are suppressed, and the dispersibility of the poorly water-soluble drug is improved while the miscibility with the water-soluble drug is improved. In addition, when instilled in the eye, the corneal permeability of the water-soluble drug can be improved together with the poorly water-soluble drug.

[0025] The suspension aid is preferably added before carrying out ultra-fine particle processing of the poorly water-soluble drug, but may also be added after the ultra-fine particle processing of the poorly water-soluble drug and mixed with the nano-sized poorly water-soluble drug.

[0026] Non-limiting examples of ultrafine particle size reduction of poorly water-soluble drugs are as follows. A mixture of powder of a poorly water-soluble drug and powder of an optional ingredient is mixed while being ground, and then the resulting drug mixture is pulverized in a bead mill (e.g., 2,000 rpm to 4,000 rpm, 10 seconds to 5 minutes, room temperature conditions) using metal beads (e.g., zirconia beads) with a diameter of about several mm, preferably 1 mm to 3 mm, to obtain a fine drug powder. The resulting fine drug powder is then suspended in an aqueous solution containing a suspension aid to obtain a suspension containing a poorly water-soluble drug. Next, the obtained suspension containing the poorly water-soluble drug, with the poorly water-soluble drug dispersed therein, is subjected to crushing in a bead mill using metal beads (e.g., zirconia beads) having a diameter of 1 mm or less, preferably 0.05 mm to 0.5 mm (e.g., conditions of 4,000 rpm to 6,500 rpm, 10 seconds to 5 minutes, about 4°C) and centrifugation (e.g., conditions of 500 g to 1,000 g, 30 seconds to 2 minutes, about 4°C) several dozen times, preferably about 30 times, to obtain a dispersion containing a nanosized poorly water-soluble drug.

[0027] In the above specific example, ultrafine particle size reduction is performed using a bead mill with metal beads, but when performing the process on an industrial scale, any suitable means for ultrafine particle size reduction of drugs suitable for industrial scale implementation may be used.

[0028] The average particle size of the nano-sized poorly water-soluble drug is not particularly limited as long as it is at the nano level, i.e., less than 1 μm. For example, when the size of corneal endothelial cells is 400 nm and the permeability of the poorly water-soluble drug through the cornea is taken into consideration, the average particle size is preferably 10 nm to 400 nm, more preferably 20 nm to 300 nm, and even more preferably 50 nm to 200 nm. The average particle size of the nano-sized poorly water-soluble drug is a value measured by number standard using a laser scattering method using a laser diffraction particle size distribution measuring device as described in the examples below. Note that the average particle size of the water-soluble drug is not particularly limited since it is dissolved in the eye drop.

[0029] The contents of the nanosized poorly water-soluble drug, water-soluble drug, and suspending aid in the eye drops are not particularly limited, and may be appropriately set depending on, for example, the desired efficacy and safety of the drug, and the solubility and average particle size of the nanosized poorly water-soluble drug.

[0030] Non-limiting preferred specific embodiments of the eye drops of the present invention include those in which the total contents of the nanosized poorly water-soluble drug, the water-soluble drug, and the suspension auxiliary are as follows, but the present invention is not limited thereto. [Specific embodiment 1 of eye drops] (1) Nanosized water-insoluble drugs: 0.01% (w / v) to 5.0% (w / v) (2) Water-soluble drugs: 0.01% (w / v) to 5.0% (w / v) [Specific embodiment 2 of eye drops] (1) Nanosized water-insoluble drugs: 0.01% (w / v) to 5.0% (w / v) (2) Water-soluble drugs: 0.01% (w / v) to 5.0% (w / v) (3) Suspension aid: 0.1% (w / v) to 10% (w / v) [Specific embodiment 3 of eye drops] (1) Nanosized water-insoluble drugs: 0.05% (w / v) to 3.0% (w / v) (2) Water-soluble drugs: 0.1% (w / v) to 1.0% (w / v) (3) Suspension aid: 3% (w / v) to 7% (w / v)

[0031] The ophthalmic solution according to one embodiment of the present invention is a homogeneous suspension containing a nano-sized poorly water-soluble drug in a well-dispersed state. The homogeneity of the ophthalmic solution according to one embodiment of the present invention is evaluated by whether it is a homogeneous suspension on the 7th day after standing. The term "homogeneous suspension on the 7th day after standing" is evaluated by either or both of the following: when the ophthalmic solution according to one embodiment of the present invention is placed in a glass tube and left standing in a dark place at room temperature for 7 days, the suspension maintains a uniform dispersion state by visual inspection, and no obvious sedimentation or clear part of the drug is observed, and when the concentration of the poorly water-soluble drug is measured by HPLC after sampling at 90% of the liquid level, 80% or more of the initial concentration is measured. The ophthalmic solution according to one embodiment of the present invention may be a homogeneous suspension on the 7th day after standing, but in order to maintain a homogeneous state, it is preferably a homogeneous suspension on the 14th day after standing, more preferably a homogeneous suspension on the 21st day after standing, and even more preferably a homogeneous suspension on the 28th day after standing.

[0032] The eye drop of one embodiment of the present invention may contain various other components in addition to the nanosized poorly water-soluble drug, the water-soluble drug, and the suspension auxiliary, as long as the other components do not interfere with the solution of the problems of the present invention. A typical example of the other components is water, since the eye drop of one embodiment of the present invention is a suspension. Examples of other components other than water include additives that are commonly used in the manufacture of eye drops, such as bases (such as aqueous ethanol); preservatives (such as benzalkonium chloride, sodium benzoate, ethanol, chlorobutanol, sorbic acid, potassium sorbate, sodium dehydroacetate, methyl parahydroxybenzoate, ethyl parahydroxybenzoate, propyl parahydroxybenzoate, butyl parahydroxybenzoate, oxyquinoline sulfate, phenethyl alcohol, benzyl alcohol, biguanide compounds, etc.); pH adjusters (such as hydrochloric acid, boric acid, aminoethylsulfonic acid, epsilon-aminocaproic acid, citric acid, acetic acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, sodium bicarbonate, sodium carbonate, borax, triethanolamine, monoethanolamine, diisopropanolamine, sulfuric acid, phosphoric acid, polyphosphoric acid, propionic acid, oxalic acid, gluconic acid, fumaric acid, lactic acid, tartaric acid, malic acid, succinic acid, gluconolactone, ammonium acetate, etc.); isotonicity agents (sodium bisulfite, sodium sulfite, potassium chloride, calcium chloride, sodium chloride, magnesium chloride, potassium acetate, sodium acetate, sodium bicarbonate, sodium carbonate, sodium thiosulfate, magnesium sulfate, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, glycerin, propylene glycol, etc.); stabilizers (dibutylhydroxytoluene, trometamol, tocopherol, sodium pyrosulfite, monoethanolamine, aluminum monostearate, glycerin monostearate, etc.); fragrances (menthol, anethole, eugenol, camphor, geraniol, cineol, borneol, limonene, rhubarb, etc.); essential oils (peppermint oil, cool mint oil, spearmint oil, peppermint oil, fennel oil, cinnamon oil, bergamot oil, eucalyptus oil, rose oil, etc.), but are not limited to these.Incidentally, some of the above compounds have a function as a suspension aid, and in that case, they may be blended to also function as a suspension aid.

[0033] The eye drop according to one embodiment of the present invention has the property of being in the form of a suspension used for the purpose of instillation. Other properties of the eye drop according to one embodiment of the present invention are not particularly limited as long as they are within the range acceptable for use as a pharmaceutical product. For example, the pH is preferably 5.0 to 8.0, and more preferably 6.0 to 7.0; the viscosity is preferably 10 mPa·s or less, and more preferably 0.5 mPa·s to 2.0 mPa·s; and the osmotic pressure ratio is preferably 0.7 to 1.6. The viscosity is a value obtained by measurement according to the method described in the Examples below, and the pH and osmotic pressure ratio may be measured according to known methods.

[0034] The eye drops according to one embodiment of the present invention are preferably instilled at one or several drops per eye once a day or in divided doses several times a day, and more preferably at one or two drops per eye once a day or in divided doses twice a day. When the eye drops according to one embodiment of the present invention are instilled in divided doses several times a day, the interval between instillations is preferably 1 hour or more, more preferably 2 hours or more, and even more preferably 3 hours or more. The volume of one drop is not particularly limited as long as it is a commonly used amount, but is preferably about 0.01 mL to about 0.1 mL, and more preferably about 0.02 mL to about 0.05 mL, for example.

[0035] The eye drops according to one embodiment of the present invention may be applied directly to the naked eye, but since the corneal permeability of the drug is good, they can also be applied when wearing contact lenses. The contact lenses may be either hard or soft contact lenses, and can be applied to all types of commercially available contact lenses, such as repeatedly used contact lenses, daily disposable contact lenses, weekly disposable contact lenses, biweekly disposable contact lenses, and colored contact lenses.

[0036] When the eye drop of one embodiment of the present invention is distributed on the market, it is preferably a container-packed eye drop. The container is not particularly limited as long as it is a container that is usually used for eye drops, and examples thereof include a multi-dose type container, a single-use unit dose type container, and a PFMD (Preservative Free Multi Dose) container. The material of the container is not particularly limited as long as it is a material that is generally used for eye drop containers, and examples thereof include resins, and specific examples thereof include resins such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene-polyethylene copolymer, polyvinyl chloride, acrylic, polystyrene, and polycyclic olefin copolymer.

[0037] Another aspect of the present invention is a method for producing the eye drop of the aspect of the present invention. The production method of the aspect of the present invention includes a step of obtaining a nano-sized poorly water-soluble drug by subjecting a poorly water-soluble drug to ultrafine processing (hereinafter also referred to as step 1), and a step of obtaining an eye drop containing the nano-sized poorly water-soluble drug and the water-soluble drug by mixing the nano-sized poorly water-soluble drug with a water-soluble drug (hereinafter also referred to as step 2).

[0038] In step 1, the poorly water-soluble drug is preferably ultrafine-divided in the presence of a suspending aid. That is, as described above, it is preferable to carry out the ultrafine-dividing treatment by adding a mixture containing the poorly water-soluble drug to an aqueous solution containing a suspending aid and subjecting the mixture to a wet grinding treatment.

[0039] In step 2, the method for mixing the nanosized poorly water-soluble drug with the water-soluble drug is not particularly limited, and examples include adding the water-soluble drug to an aqueous solution containing the nanosized poorly water-soluble drug and mixing until a homogenous suspension is obtained.

[0040] In addition to steps 1 and 2, the production method according to one embodiment of the present invention may include additional steps, such as a step of adjusting the pH, viscosity, osmotic pressure, etc., within a predetermined range, and a step of heat sterilization, as necessary.

[0041] According to the production method of one aspect of the present invention, the solubility of a poorly water-soluble drug is improved, the miscibility with a water-soluble drug is enhanced, and aggregation and precipitation of the drug can be suppressed, so that an eye drop with high uniform dispersion can be obtained, and as a result, an eye drop in which unevenness in the drug concentration between each instillation is eliminated can be obtained.

[0042] Another aspect of the present invention is a method for improving the corneal permeability of a poorly water-soluble drug and a water-soluble drug by using the eye drops according to one aspect of the present invention. The method for improving the corneal permeability of one aspect of the present invention includes a step of contacting the cornea with an eye drop containing a nanosized poorly water-soluble drug and a water-soluble drug, thereby improving the corneal permeability of the poorly water-soluble drug and the water-soluble drug, compared to the case of contacting the cornea with an eye drop containing a non-nanosized poorly water-soluble drug and a water-soluble drug.

[0043] In the method of one aspect of the present invention, the nano-sized poorly water-soluble drug is preferably a nano-sized poorly water-soluble drug obtained by subjecting the poorly water-soluble drug to ultrafine processing in the presence of a suspension aid. In this case, the ultrafine size of the poorly water-soluble drug and the improvement in the solubility of the poorly water-soluble drug by the suspension aid work together to increase the adhesion and retention of the poorly water-soluble drug to the cornea, and it is expected that the efficacy of the drug in the cornea will be improved. In addition, the corneal permeability by the active transport mechanism will be increased not only for poorly water-soluble drugs but also for water-soluble drugs, and the migration of both of these drugs into the eye will be improved.

[0044] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples, and the present invention can take various forms as long as the object of the present invention can be achieved. EXAMPLES

[0045] In the present examples, "%" indicating the content of a component indicates "mass volume percent concentration (w / v%)". Statistical analysis was performed using unpaired Student's t-test for comparison between two groups, and Dunnett's multiple comparison for comparison between multiple groups. A significant difference was determined when p<0.05.

[0046] Fluorometholone and rebamipide were used as poorly water-soluble drugs. Levofloxacin, bromfenac sodium, and timolol maleate were used as water-soluble drugs. 2-hydroxypropyl-β-cyclodextrin was used as cyclodextrin. Using these, mixed eye drops containing two types of drugs, a finely divided poorly water-soluble drug and a water-soluble drug, were prepared, and the degree of dispersion and dispersion stability of the poorly water-soluble drug in the mixed eye drops, as well as the corneal permeability were evaluated.

[0047] [Preparation of test mixed eye drops] 1. Suspension containing nanosized fluorometholone, bromfenac sodium, and levofloxacin (FBL-NPs) 0.2 g of fluorometholone (FL) bulk powder (average particle size: 4 μm-5 μm), 0.0004 g of benzalcohol chloride (BAC), 0.04 g of D-mannitol, and 0.2 g of methylcellulose (MC) were ground in an agate mortar for about 1 hour to obtain a drug mixture. The resulting drug mixture was then placed in a 2.0 mL tube containing 2.0 g of zirconia beads with a diameter of 2.0 mm, and milled using a bead mill (3,000 rpm, 30 seconds, with cooling; Waken Pharmaceutical Co., Ltd.) to obtain a fine drug powder. The resulting fine drug powder was suspended in a 5% aqueous solution of 2-hydroxypropyl-β-cyclodextrin (HPβCD) to prepare a 0.5% fluorometholone-containing suspension.

[0048] The obtained 0.5% fluorometholone-containing suspension was dispersed using a benchtop ultrasonic cleaner to disperse the components in the liquid, and then poured into a 2.0 mL tube containing 2 g of 0.1 mm diameter zirconia beads until the tube was approximately 80% full. The suspension was then crushed using a bead mill (5,500 rpm, 30 seconds, 4°C) and centrifuged (800 g, 60 seconds, 4°C) 30 times to prepare a fluorometholone nanoparticle-containing dispersion (FL-NPs).

[0049] Furthermore, bromfenac sodium (BF) and levofloxacin (LV) were dissolved in the obtained FL-NPs to prepare a suspension (FBL-NPs) containing final concentrations of 0.1% FL, 0.001% BAC, 0.1% D-mannitol, 5% HPβCD, 0.5% MC, 0.1% BF and 0.5% LV.

[0050] The pH of FBL-NPs was measured at room temperature using a pH meter (main unit: Seven Compact S220, electrode: InLab MicroPro-ISM) (manufactured by Mettler Toledo) and was found to be approximately 6.5.

[0051] The viscosity of FBL-NPs was measured by the spindle rotor method using an RB80 type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 60 rpm for 3 minutes after adjusting 20 mL of the sample to 20 °C and immersing a BL adapter (code No. 10). The viscosity was 1.2 mPa s to 1.7 mPa s.

[0052] 2. Suspension containing nanosized rebamipide and timolol maleate (TM / REB-NPs) In a manner similar to the preparation method for FBL-NPs, rebamipide (REB) bulk powder (average particle size: 0.05 μm to 0.2 μm) was used as the poorly water-soluble drug, and timolol maleate (TM) was used as the water-soluble drug, to prepare a suspension (TM / REB-NPs) containing a final concentration of 2% REB, 0.5% TM, 0.001% BAC, 0.1% D-mannitol, 5% HPβCD, and 0.5% MC.

[0053] 3. Suspension containing fluorometholone, bromfenac sodium and levofloxacin (FBL-MPs) 0.2g of FL bulk powder, 0.0004g of BAC, 0.04g of D-mannitol, and 0.2g of MC were ground in an agate mortar for about 1 hour to obtain a drug mixture. The obtained drug mixture was then placed in a 2.0mL tube containing 2.0g of zirconia beads with a diameter of 2.0mm, and milled using a bead mill (3,000rpm, 30 seconds, with cooling; Wakenyaku Co., Ltd.) to obtain a fine drug powder. The obtained fine drug powder was suspended in a 5% HPβCD aqueous solution to prepare a 0.5% fluorometholone-containing suspension.

[0054] The components of the obtained 0.5% fluorometholone-containing suspension were dispersed using a benchtop ultrasonic cleaner, and BF and LV were further dissolved to prepare a suspension (FBL-MPs) in which the final concentration of each component was the same as that of FBL-NPs and in which FL was not nanosized.

[0055] 4. Suspension containing rebamipide and timolol maleate (TM / REB-MPs) In a similar manner to the preparation of FBL-MPs, a suspension was prepared using REB as the poorly water-soluble drug and TM as the water-soluble drug, containing final concentrations of 2% REB, 0.5% TM, 0.001% BAC, 0.1% D-mannitol, 5% HPβCD and 0.5% MC (TM / REB-MPs).

[0056] 5. Commercially available eye drops (CA-FL, CA-BF, CA-LV, CA-REB) The commercially available FL eye drops used were "Flumetholone eye drops 0.1%" (0.1% FL; manufactured by Santen Pharmaceutical Co., Ltd.) (CA-FL), the commercially available BF eye drops used were "Bronac eye drops 0.1%" (0.1% BF; manufactured by Senju Pharmaceutical Co., Ltd.) (CA-BF), the commercially available LV eye drops used were "Cravit eye drops" (0.5% LV; manufactured by Santen Pharmaceutical Co., Ltd.) (CA-LV), and the commercially available REB eye drops used were "Mucosta eye drops UD 2%" (2% REB; manufactured by Otsuka Pharmaceutical Co., Ltd.) (CA-REB).

[0057] [Measurement of the average particle size of poorly water-soluble drugs in the test mixed eye drops] The average particle size of fluorometholone in FBL-MPs and FBL-NPs was measured by number standard using laser scattering method with laser diffraction particle size distribution analyzer "SALD-7100" (Shimadzu Corporation). The measurement results of bulk fluorometholone in FBL-MPs are shown in Figure 1A, and the measurement results of nanoized fluorometholone in FBL-NPs are shown in Figure 1B. As these results show, the average particle size of bulk fluorometholone was 3.98 μm, while the average particle size of nanoized fluorometholone was 74 nm, confirming that it was sufficiently finely divided.

[0058] In addition, nano-sized fluorometholone was measured by number using a nano-tracking particle size measurement device "NANOSIGHT LM10" (Malvern). The results are shown in Figure 1C. As shown in Figure 1C, the average particle size of nano-sized fluorometholone was 119 nm, and it was found to be nano-sized by the nano-tracking method.

[0059] Furthermore, the results of photographing nano-sized fluorometholone using a scanning probe microscope "SPM-9700" (Shimadzu Corporation) are shown in Figure 1D. As shown in Figure 1D, the image also shows that the nano-sized fluorometholone is nano-sized.

[0060] [Measurement of the degree of dispersion of poorly water-soluble drugs in the test mixed eye drops] 10 mL of FBL-NPs and 10 mL of FBL-MPs were each taken and centrifuged at a relative centrifugal force of 100,000 g for 60 minutes using a centrifuge "Optima MAX-MP" (manufactured by BECKMAN COULTER), and the supernatant was collected. The concentration of fluorometholone in the obtained supernatant was measured by high performance liquid chromatography according to a conventional method.

[0061] The measurement results confirmed that FBL-NPs containing nanosized fluorometholone had a higher concentration of fluorometholone in the supernatant and a higher degree of dispersion in the mixed eye drops than FBL-MPs containing bulk fluorometholone powder.

[0062] [Measurement of dispersion stability of poorly water-soluble drugs in test mixed eye drops] 20 mL of FBL-NPs, 20 mL of FBL-MPs and 20 mL of CA-FL were each dispensed into a glass tube and left to stand in a dark place at room temperature. At this time, the height of the liquid surface in the glass tube was 4 cm from the bottom. At the start of the standing (0 d) and on the 1st, 4th, 7th, 14th, 21st and 28th days (1M) after the standing, 50 μL samples were taken from each glass tube at 0.4 cm (90% part) from the liquid surface, and the fluorometholone concentration was measured using high performance liquid chromatography. In the same manner, the rebamipide concentration was measured for TM / REB-NPs, TM / REB-MPs and CA-REB.

[0063] The results of measuring the fluorometholone concentration and rebamipide concentration over time are shown in FIG. 2A and FIG. 2B, respectively.

[0064] Furthermore, photographs of the 0d and 1M glass tubes are shown in Figure 2C. These were also visually inspected and the dispersibility of fluorometholone was evaluated according to the following criteria, and the results are shown in Table 1. <Evaluation of dispersibility> ○: Uniformly dispersed △: Some of the drug precipitated and clear parts were observed in the solution. ×: The drug has completely precipitated and the solution is clear.

[0065] [Table 1]

[0066] As shown in Figures 2A and 2B, the mixed eye drops containing nanosized fluorometholone and nanosized rebamipide had fluorometholone and rebamipide concentrations of approximately 90% on the first day after the start of storage, whereas the concentrations of the mixed eye drops containing microsized fluorometholone and rebamipide were approximately 25% and 10%, respectively, and only a few percent in the commercially available eye drop suspension.

[0067] Furthermore, as shown in Figure 2C, visual inspection confirmed that the mixed eye drops containing nanosized fluorometholone maintained a dispersed state, whereas the mixed eye drops containing microsized fluorometholone and the commercially available eye drop suspension were found to aggregate and / or settle out of fluorometholone when left to stand.

[0068] Furthermore, the particle count of fluorometholone in a mixed eye drop containing nanoized fluorometholone with an average particle size of less than 1 μm was measured immediately after preparation (day 0) and on day 28. As shown in Figure 2D, it was confirmed that the concentrations of both were almost constant.

[0069] From the above results, it was found that nano-sizing a poorly water-soluble drug improves the dispersibility during preparation and the long-term dispersion stability in a mixed eye drop containing a poorly water-soluble drug and a water-soluble drug.

[0070] [Measurement of corneal permeability (in vitro) of poorly water-soluble drugs in the test mixed eye drops] As shown in Figure 3, a device was prepared in which a donor chamber and a reservoir chamber were separated by a rabbit cornea. The rabbit cornea had a total thickness of 520 µm (epithelial layer 50 µm; stromal layer 450 µm; endothelial layer 20 µm).

[0071] The donor chamber was filled with 3.0 mL of the test mixed eye drop or a commercially available eye drop suspension, and the reservoir chamber was filled with 3.0 mL of glucose-containing HEPES (4-(2-hydroxyethyl)-1-piperazine·ethanesulfonic acid) buffer solution.

[0072] The device was incubated in a water bath set at 35°C, and 50μL of samples were taken from the reservoir chamber 30, 60, 120, 240, 300 and 360 minutes after the start of the measurement, and the concentration of fluorometholone in the samples was measured using high performance liquid chromatography. The results are shown in Figure 4.

[0073] In the case of the commercially available eye drop suspension (CA-FL), the fluorometholone concentration on the reservoir side did not increase, indicating that drug permeation was hindered by the rabbit cornea.In contrast, in the case of the mixed eye drop containing nanosized fluorometholone (FBL-NPs), the fluorometholone concentration in the samples taken from the reservoir chamber increased over time, indicating that the nanosized drug has excellent corneal permeability.

[0074] [Measurement of corneal permeability (in vivo) of each drug in the test mixed eye drops] The corneal permeability of each drug was evaluated for the test mixture eye drops, FBL-NPs, and three commercially available eye drops containing fluorometholone, bromfenac sodium, and levofloxacin alone (CA-FL, CA-LV, and CA-BF).

[0075] A schematic diagram of the test outline is shown in Figure 5. After administering influenza inhalation anesthesia to male Japanese white rabbits, a microsyringe equipped with a silicone tube (φ0.5 mm) with an insulin injection needle (29G) at the tip was used to puncture the eye just below the cornea. 5 mL of the test eye drops or 5 mL of a commercially available eye drop was dripped into the rabbit's eye in this state. After dripping, 5 μL of aqueous humor in the rabbit's eye was collected into the microsyringe every 10 minutes for up to 90 minutes. The drug concentration in the collected aqueous humor was measured using high performance liquid chromatography.

[0076] The results of measuring the concentrations of fluorometholone, bromfenac sodium, and levofloxacin over time in the collected aqueous humor when FBL-NPs, or CA-FL, CA-LV, and CA-BF were instilled, respectively, are shown in Figure 6.

[0077] As shown in Figure 6A, for the poorly water-soluble drug fluorometholone, the fluorometholone concentration was higher at all measurement times when the mixed eye drops containing nanoized fluorometholone were instilled compared to when the commercially available eye drops were instilled. This result demonstrated that nano-processing of the poorly water-soluble drug fluorometholone improves corneal permeability.

[0078] As shown in Figures 6B and 6C, it was surprising that when the poorly water-soluble drug fluorometholone was nanosized, the concentrations of not only fluorometholone but also the coexisting water-soluble drugs bromfenac sodium and levofloxacin were higher at all measurement times when the mixed eye drops containing nanosized fluorometholone were instilled compared to when the commercially available eye drops were instilled. This result indicates that nanoizing the poorly water-soluble drug fluorometholone synergistically improves the corneal permeability of water-soluble drugs that coexist in a mixed state with nanosized fluorometholone. [Industrial Applicability]

[0079] The eye drops and method of one embodiment of the present invention have high dispersion stability of the drug and are capable of maintaining a homogeneous suspension state. Furthermore, due to excellent corneal permeability of the drug, the pharmacological action of the drug can be effectively applied to ocular tissues, and can contribute to the health and welfare of individuals seeking treatment and prevention of eye diseases such as cataracts and glaucoma.

Claims

1. An eye drop comprising a nanosized poorly water-soluble drug and a water-soluble drug, and being a homogeneous suspension after 7 days of standing, Further containing 2-hydroxypropyl-β-cyclodextrin as a suspending aid. The eye drops.

2. The eye drop according to claim 1, wherein the nanosized poorly water-soluble drug has an average particle size of 10 nm to 400 nm.

3. 3. The eye drop according to claim 1, further comprising at least one suspending aid selected from the group consisting of surfactants, sugars, sugar alcohols, water-soluble polymers and amino acids.

4. A step of obtaining a nano-sized poorly water-soluble drug by subjecting the poorly water-soluble drug to ultrafine processing; A step of obtaining an eye drop containing the nanosized poorly water-soluble drug and the water-soluble drug by mixing the nanosized poorly water-soluble drug and the water-soluble drug. A method for producing an eye drop comprising the steps of: The ultrafine-graining treatment is performed in the presence of 2-hydroxypropyl-β-cyclodextrin as a suspension aid. The manufacturing method.

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