Eye-use pilocarpine ion-sensitive in-situ gel preparation

Abstract

The invention provides pilocarpine hydrochloride ion-sensitive in-situ gel eye drops and a preparation method thereof, and a long-acting ophthalmic preparation capable of retarding presbyopia in presbyopia diseases.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eye drops, in particular to a pilocarpine hydrochloride ion-sensitive in-situ gel eye drop and a preparation method thereof, and also includes the application of the pilocarpine hydrochloride ion-sensitive in-situ gel eye drop in presbyopia. BACKGROUND

[0002] Presbyopia, also known as presbyopia, with the increase of age, the lens gradually hardens, the elasticity decreases, the function of ciliary muscle gradually decreases, and the accommodation function of the eye gradually decreases, resulting in a decrease in zoom, and the image cannot be completely focused on the retina. Presbyopia usually occurs at the age of 38, and the peak of the disease is at the age of 42-44, and almost all patients will have presbyopia symptoms at the age of 50.

[0003] For the solution of presbyopia, eye surgery has the advantages of short operation time, fast recovery time and lightening the burden of wearing glasses, but many patients have surgery resistance, and early surgery treatment often cannot completely correct the degree of presbyopia, and there is a possibility of recurrence, so a considerable number of patients choose not to treat or wear presbyopic glasses. Although presbyopic glasses are the most common solution to near vision correction, many people find glasses inconvenient or unwilling to wear for aesthetic reasons. The biggest problem of wearing glasses is that glasses are inconvenient to store and are easy to fog in spaces with temperature differences. These are inconvenient for the elderly, especially in winter and when wearing a mask. For myopic patients who develop presbyopia in old age, they need to wear two single-vision lenses alternately, and this group of people need to frequently change glasses or choose bifocal lenses and progressive multifocal lenses, and some people cannot adapt to multifocal glasses, thereby causing a series of inconvenience or affecting the quality of life.

[0004] For the above-mentioned problems faced by presbyopia patients, it is necessary to develop a therapy that is easy for patients to accept. At present, the most common dosage form for treating eye diseases is eye drops. In the prior art, the eye drops for treating presbyopia include cholinergic agonists such as pilocarpine, carbachol, aceclidine, cevimeline, etc., which can cause pupil contraction to enhance the focusing depth, or stimulate ciliary muscle contraction to increase ciliary muscle contraction force, thereby improving near vision and intermediate vision. At present, only two kinds of pilocarpine hydrochloride eye drops have been approved for the treatment of presbyopia worldwide. In October 2021, Vuity 1.25% pilocarpine hydrochloride eye drops developed by Allergan, a subsidiary of AbbVie, were approved for marketing in the United States as the first eye drops for the treatment of presbyopia. The initial approved dosing frequency of Vuity is once a day. However, due to the short duration of action of Vuity, which is an ordinary solution eye drop, in March 2023, Allergan announced that the FDA had approved Vuity twice a day for adults with presbyopia, with an additional drop in each eye for the second dose, which can be given 3-6 hours after the initial dose. In October 2023, Qlosi 0.4% pilocarpine hydrochloride eye drops developed by Orasis Pharmaceuticals Ltd. were approved for marketing in the United States, and the dosing frequency is still twice a day, which requires the second dose to be given 3 hours after the initial dose. Frequent dosing is inconvenient for presbyopia patients, and in a survey of 1358 presbyopia patients, most people (80%) in different age groups expressed their choice to receive eye drops once a day. Therefore, it is necessary to develop an eye preparation that can long-acting and continuously reduce the effect of presbyopia at the present stage.

[0005] The ordinary eye drops are generally aqueous solution dosage forms of drugs. After eye drop administration, the drug is rapidly lost from the ocular surface due to blinking, flushing by tears, and drainage effect of the tear duct. Due to the special physiological barrier of the eye, the drug is difficult to enter the eye tissue, and the bioavailability is low (5%), the effect is short, and frequent administration is required. After absorption from the nose and pharynx, it may also cause systemic toxicity, thus often reducing the patient's medication compliance and affecting the treatment effect of the disease. Studies have shown that in situ gel eye drops can rapidly phase transition into a semi-solid gel preparation at the drug administration site after changes in the environment (temperature, pH, ionic strength, etc.). Through adhesion, the drug effect time is prolonged, and the purpose of slow drug release is achieved, showing good application prospects in improving bioavailability and reducing adverse reactions. Among them, temperature-sensitive in situ gel eye drops require the use of a high proportion of polymer materials such as poloxamer, and the formed gel has a relatively hard texture, which affects the safety of the cornea. pH-sensitive in situ gels depend on a large change in pH and are not suitable for the eye environment. Currently, there is no pH-sensitive in situ gel eye drops approved for marketing. Ion-sensitive in situ gels have been tested by the market and patients for a long time. In November 1993, FDA approved the marketing of TIMOPTIC-XE, an ion-sensitive in situ gel eye drop containing timolol maleate. Clinical studies have found that the test group using TIMOPTIC-XE once a day and the control group using TIMOPTIC twice a day have the same effect on reducing intraocular pressure, and the same therapeutic effect can be achieved while reducing the frequency of administration, which also confirms the safety of using gellan gum as the matrix of ion-sensitive gels. However, in commercially available eye drops containing gellan gum, the concentration of gellan gum needs to reach 0.5%-1.0% (mass / mass) to have the ability to form in situ gels, which increases the cost of research and production.

[0006] Currently, there is no sustained-release preparation for treating presbyopia approved for marketing on the market. ARVN003 (pilocarpine micro eye solution) developed by Jiemu Biotech for treating presbyopia has already carried out clinical phase 3 research, but it needs to be combined with Optejet for administration, resulting in high cost and high administration concentration; Shenyang Xingqi Pharmaceutical Co., Ltd. has disclosed an ophthalmic pilocarpine hydrochloride microemulsion and a preparation method (CN117731611A). Since the microemulsion is a heterogeneous system, the water phase, oil phase, and surfactant need to be selected, and the production and quality control are difficult; Nanjing Jiqun Pharmaceutical Technology Co., Ltd. has disclosed a M-choline receptor agonist compound, its preparation method and use (WO2023143575A1), which is a new salt type of pilocarpine, but its preparation form is still a common solution eye drop.

[0007] CN101342172A discloses a method for preparing a pilocarpine nitrate eye-forming gel using polyethylene glycol and methyl cellulose, the gel matrix is high in amount (3% to 10%), the prepared temperature-sensitive eye-forming gel phase transition is 28 to 36 DEG C, and the gel is not conducive to eye drop operation of patients in high-temperature conditions such as summer, and the related substances and the polymerization degree of the polyethylene glycol with high polymerization degree are difficult to control, which is not conducive to industrial application, and in addition, all the prescriptions contain ethanol.

[0008] CN101564374A discloses a method for preparing eye-forming gels of multiple drugs using gellan gum, but it is difficult to obtain long-time eye retention by simply mixing the gellan gum itself or a conventional gel matrix, because the gellan gum cannot exert the maximum advantage of ion sensitivity.

[0009] CN118765279A discloses a method for preparing a new compound for treating presbyopia by connecting a disulfide bond reducing agent with pilocarpine, but the method is relatively complex, difficult to prepare, and difficult to control the related substances, and the disulfide bond active softening lens for treating presbyopia has not been clinically proven.

[0010] Therefore, it is urgent to develop an eye preparation for slowing down presbyopia with a slow-release effect at the present stage. SUMMARY

[0011] The purpose of the present application is to develop a slow-release pilocarpine eye drop, reduce the frequency of drug administration of patients, improve the compliance of patients, and reduce the risk of adverse reactions caused by low bioavailability of conventional eye drops and easy system exposure. The in-situ gel preparation of the present application comprises a M cholinergic receptor agonist, a gel matrix, an ion concentration regulator, an osmotic pressure regulator, a pH regulator, a preservative, and water. When the preparation is used in the eye of a subject, an in-situ gel containing a M cholinergic receptor agonist is formed. Examples of the eye disease include but are not limited to presbyopia, myopia, glaucoma, etc.

[0012] The present application provides an ion-sensitive in-situ gel preparation for the eye, which comprises:

[0013] a pharmaceutically active ingredient, which is pilocarpine hydrochloride;

[0014] a gel matrix selected from deacetylated gellan gum, sodium alginate, xanthan gum, hydroxypropyl methyl cellulose, or polyethylene glycol, or a combination of two or more thereof.

[0015] As one embodiment, the gel base is selected from the group consisting of deacetylated gellan gum, or a combination of deacetylated gellan gum-sodium alginate, deacetylated gellan gum-xanthan gum, deacetylated gellan gum-hydroxypropyl methylcellulose, or deacetylated gellan gum-polyethylene glycol; and

[0016] an ionic strength adjusting agent present in an amount of 0.15% to 0.25% w / w based on the weight of the gel, the ionic strength adjusting agent comprising sodium chloride, potassium chloride, or calcium chloride, or a combination of two or more thereof. By way of illustrative example, the ionic strength adjusting agent can be present in an amount of 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, or 0.15% to 0.25% w / w.

[0017] The ophthalmic ion-sensitive in situ gel formulation of the present application is instilled into the eye as a solution and rapidly undergoes phase transition from a liquid to a semi-solid gel formulation upon contact with the tear fluid.

[0018] As one embodiment of the present application, the ophthalmic ion-sensitive in situ gel formulation can further comprise a tonicity adjusting agent, a pH adjusting agent, a preservative, or water, or a combination of two or more thereof.

[0019] In some embodiments of the present application, the ionic strength adjusting agent is preferably sodium chloride.

[0020] In some embodiments of the present application, the ionic strength adjusting agent is preferably present in an amount of 0.15% w / w, 0.16% w / w, 0.17% w / w, 0.18% w / w, 0.19% w / w, 0.2% w / w, 0.25% w / w, more preferably 0.15% w / w, 0.2% w / w, 0.25% w / w, most preferably 0.2% w / w, based on the weight of the gel.

[0021] In some embodiments of the present application, the active ingredient pilocarpine hydrochloride is present in an amount of 0.3% to 1.5% w / w, preferably 0.4% w / w or 1.25% w / w. By way of illustrative example, the active ingredient pilocarpine hydrochloride can be present in an amount of 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 0.3% to 1.5% w / w.

[0022] In some embodiments of the present application, the gelling agent is present in an amount of 0.2% to 0.8% w / w, preferably 0.3% w / w, 0.4% w / w, 0.45% w / w, 0.5% w / w, 0.6% w / w, 0.7% w / w, more preferably 0.4% w / w, 0.6% w / w, based on the weight of the gel.

[0023] In some embodiments of the present application, the ion-sensitive in situ gelling formulation further comprises an osmotic pressure adjusting agent selected from one or more of mannitol, glycerol, polyethylene glycol 400.

[0024] In some embodiments of the present application, the osmotic pressure adjusting agent is present in an amount of 1% to 5% w / w, preferably 1.1% to 4% w / w, more preferably 1.15% w / w, 2% w / w, 2.3% w / w, 2.5% w / w, 3% w / w, 3.2% w / w, 3.5% w / w, 4% w / w, most preferably 2% w / w or 3.5% w / w, based on the weight of the gel. By way of illustrative example, the osmotic pressure adjusting agent can be present in an amount of 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, or any real number within the range of 1% to 5% w / w.

[0025] In some embodiments of the present application, the ion-sensitive in situ gelling formulation further comprises a pH adjusting agent selected from one or more of disodium edetate, hydrochloric acid, sodium hydroxide, tromethamine.

[0026] In some embodiments of the present application, the preservative is selected from one or more of benzalkonium chloride, methylparaben, chlorobutanol, potassium sorbate.

[0027] In some embodiments of the present application, the ion-sensitive in situ gelling formulation further comprises a preservative present in an amount of 0.001% to 0.5% w / w, preferably 0.005% to 0.01% w / w, more preferably 0.0075% w / w, 0.01% w / w, most preferably 0.0075% w / w, based on the weight of the gel. By way of illustrative example, the preservative can be present in an amount of 0.1%, 0.2%, 0.3%, 0.4%, or any real number within the range of 0.001% to 0.5% w / w.

[0028] In some embodiments of the present application, the ophthalmic ion-sensitive in situ gelling formulation further comprises an amount of water sufficient to provide a total weight of the formulation of 1 gram.

[0029] In some embodiments of the present application, the ion-sensitive in situ gelling formulation comprises pilocarpine hydrochloride 0.3% to 1.5% w / w, deacetylated gellan gum 0.2% to 0.8% w / w, sodium chloride 0.15% to 0.20% w / w, mannitol 1% to 5% w / w, benzalkonium chloride 0.001% to 0.5% w / w, tromethamine 0.001% to 0.05% w / w, purified water (i.e. the balance of the formulation).

[0030] In some embodiments of the present application, the ion-sensitive in situ gelling formulation comprises pilocarpine hydrochloride 0.3% to 1.5% w / w, deacetylated gellan gum 0.2% to 0.8% w / w, sodium chloride 0.15% to 0.20% w / w, mannitol 1% to 5% w / w, benzalkonium chloride 0.001% to 0.5% w / w, purified water (i.e. the balance of the formulation).

[0031] In some embodiments of the present application, the pilocarpine hydrochloride is present in an amount of preferably 0.4% w / w or 1.25% w / w.

[0032] In some embodiments of the present application, the deacetylated gellan gum is present in an amount of preferably 0.3% w / w, 0.4% w / w, 0.45% w / w, 0.5% w / w, 0.6% w / w, 0.7% w / w, more preferably 0.4% w / w, 0.6% w / w, by weight of the gel.

[0033] In some embodiments of the present application, the sodium chloride is present in an amount of preferably 0.15% w / w, 0.16% w / w, 0.17% w / w, 0.18% w / w, 0.19% w / w, 0.2% w / w, more preferably 0.15% w / w, 0.2% w / w, most preferably 0.2% w / w, by weight of the gel.

[0034] In some embodiments of the present application, the mannitol is present in an amount of preferably 2% to 4% w / w, more preferably 2% w / w, 2.3% w / w, 2.5% w / w, 3% w / w, 3.2% w / w, 3.5% w / w, 4% w / w, most preferably 2% w / w, 3.2% w / w, or 3.5% w / w, by weight of the gel. By way of example, the mannitol can be present in any real number within the range of 2% to 4% w / w.

[0035] In some embodiments of the present application, the benzalkonium chloride is present in an amount of preferably 0.005% to 0.01% w / w, more preferably 0.0075% w / w, by weight of the gel. By way of example, the benzalkonium chloride can be present in any real number within the range of 0.006%, 0.007%, 0.008%, 0.009%, or 0.005% to 0.01% w / w.

[0036] In some embodiments of the present application, the tromethamine is preferably present in an amount of 0.01% w / w or 0.002% w / w of the weight of the gel.

[0037] In some embodiments of the present application, when the mannitol is preferably present in an amount of 3.2% to 4% w / w of the weight of the gel, the sodium chloride is preferably present in an amount of 0.15% to 0.2% w / w of the weight of the gel, and when the mannitol is most preferably present in an amount of 3.5% w / w of the weight of the gel, the sodium chloride is present in an amount of 0.2% w / w of the weight of the gel.

[0038] In some embodiments of the present application, the pH value of the ion-sensitive in-situ gel formulation is in the range of 4.0 to 6.0, preferably 4.5 to 5.5, and more preferably 5.0 to 5.5. As an illustrative example, the pH value can be any real value in the range of 4.0 to 6.0.

[0039] The eye ion-sensitive in-situ gel formulation provided by the present application can be used for the preparation of a medicament for the treatment of ophthalmic diseases, preferably presbyopia, old vision, and glaucoma.

[0040] The present application provides a preparation method of the eye ion-sensitive in-situ gel formulation of pilocarpine hydrochloride, which specifically comprises the following steps:

[0041] 1) precisely weigh the prescribed amount of gel matrix into a suitable amount of stirring purified water, disperse uniformly, and continue to stir at 80°C until clear and transparent, cool to room temperature, and stand for sufficient swelling to obtain a blank gel solution;

[0042] 2) precisely weigh the prescribed amount of ion concentration regulator, osmotic pressure regulator, and preservative into a suitable amount of purified water, dissolve completely, and if necessary, heat appropriately to dissolve completely, then add the prescribed amount of pilocarpine hydrochloride and dissolve completely;

[0043] 3) mix the solution in step 2) with the solution in step 1) uniformly, detect the pH value, and use a pH regulator to adjust the pH value to 5.0 to 5.5;

[0044] 4) supplement the remaining amount of water, mix uniformly, filter at 40°C using a 0.22 μm microporous filter membrane while hot, and dispense, thereby obtaining the product.

[0045] The in-situ gel ophthalmic preparation of the present application with ion-sensitive polysaccharide as a gel matrix will optimize the prescription of pilocarpine hydrochloride in-situ gel by studying the viscosity change of the gel matrix before and after adding artificial tears (34°C, close to human body temperature, i.e. temperature after entering the eye). The viscosity of the gel matrix after adding artificial tears at 34°C is expected to be higher than that before adding artificial tears. Only such a gel matrix can form an in-situ gel with the characteristics of resisting dilution by tears. The ion-sensitive in-situ gel ophthalmic preparation of the present application has obvious thixotropy. They form a semi-solid gel under normal static conditions, but can become a free-flowing liquid immediately after shaking. Such characteristics help the liquid drop to spread on the ocular surface and reduce the foreign body sensation.

[0046] The in-situ gel ophthalmic preparation containing pilocarpine of the present application not only delays the erosion and release of the drug, thereby prolonging the residence time of pilocarpine in the conjunctival sac, but also reduces the number of drug administrations and reduces the irritation of pilocarpine to the eye, making it more suitable for clinical application.

[0047] The in-situ gel ophthalmic preparation containing pilocarpine of the present application can accelerate the speed of gel formation by adding an ion concentration regulator. In addition, the proportion of deacetylated gellan gum in the prescription can be reduced, reducing the research and production cost while providing better sustained-release effect. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 : Viscosity change of Comparative Example 1 before and after mixing with different proportions of simulated artificial tears;

[0049] Figure 2 : Viscosity change of Example 3 before and after mixing with different proportions of simulated artificial tears;

[0050] Figure 3 : Viscosity change of Example 32 before and after mixing with different proportions of simulated artificial tears;

[0051] Figure 4 : Viscosity change of Example 33 before and after mixing with different proportions of simulated artificial tears;

[0052] Figure 5 : Erosion curves of Example 7, Example 32 and Example 33 measured by the membrane-free method;

[0053] Figure 6 : Release curves of Example 7, Example 32 and Example 33 measured by the membrane-free method;

[0054] Figure 7In-vitro release curves of 1.25% pilocarpine hydrochloride control solution, Comparative Example 9, Example 32, Example 33 measured by dialysis bag method. DETAILED DESCRIPTION

[0055] The present application is further illustrated in detail by the following examples. These examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[0056] Comparative Examples 1-2: Preparation of pilocarpine hydrochloride ion-sensitive in-situ gel

[0057] 1) Preparation of deacetylated gellan gum mother liquor: 1 g of deacetylated gellan gum was slowly added to 99 g of stirring deionized water, uniformly dispersed, and stirred in a water bath at 80°C until clear and transparent, cooled to room temperature, and placed in a refrigerator for sufficient swelling. A 1% (w / w) deacetylated gellan gum mother liquor was prepared and used as needed.

[0058] 2) Drug-containing solution: The prescribed amount of mannitol and benzalkonium chloride was weighed according to Table 1, and an appropriate amount of water was added until complete dissolution. If necessary, heating was applied until complete dissolution. Then, the prescribed amount of pilocarpine hydrochloride was added and dissolved completely.

[0059] 3) From the 1% (w / w) deacetylated gellan gum mother liquor in 1), 0.6% (w / w) of the deacetylated gellan gum solution was weighed and mixed uniformly with the drug-containing solution in 2).

[0060] 4) The remaining water in the prescription was added and thoroughly mixed. The pilocarpine hydrochloride ion-sensitive in-situ gel was obtained by filtering and sterilizing at 40°C using a 0.22 μm microporous filter.

[0061] Table 1

[0062]

[0063] The different consistencies of pilocarpine hydrochloride ion-sensitive in-situ gels with different contents indicate that the hydrogen ions released from pilocarpine hydrochloride can affect the gelation behavior of deacetylated gellan gum.

[0064] Examples 1-15

[0065] 1) Preparation of deacetylated gellan gum mother liquor: 1 g of deacetylated gellan gum was slowly added to 99 g of stirring deionized water, uniformly dispersed, and stirred in a water bath at 80°C until clear and transparent, cooled to room temperature, and placed in a refrigerator for sufficient swelling. A 1% (w / w) deacetylated gellan gum mother liquor was prepared and used as needed.

[0066] 2) Drug-containing solution: the prescription amount of ion concentration regulator, mannitol, benzalkonium chloride was weighed according to Table 2, and a proper amount of water was added until it was completely dissolved, and it could be heated to completely dissolve, and then the prescription amount of pilocarpine hydrochloride was added and dissolved completely;

[0067] 3) The prescription proportion of 0.6% (w / w) deacetylated gellan gum solution was weighed from 1% (w / w) deacetylated gellan gum mother liquor in 1), and mixed uniformly with the drug-containing solution in 2);

[0068] 4) The remaining water in the prescription was supplemented, and thoroughly mixed, filtered and sterilized at 40°C with a 0.22 μm microporous filter, to obtain pilocarpine hydrochloride ion-sensitive in-situ gel.

[0069] Preparation of simulated artificial tear solution: NaHCO3: 2.18 g; NaCl: 6.78 g; CaCl2·2H2O: 0.084 g; KCl: 1.38 g; dissolved in 1000 mL of deionized water, and the pH of the solution was adjusted to 7.4 with hydrochloric acid.

[0070] Gel evaluation: the prepared sample was mixed uniformly with the simulated artificial tear solution at a ratio of 40:7 (v / v) at 34°C, and the change in gel strength before and after mixing was evaluated: + liquid that can flow; ++ slightly thick gel; +++ strong gel.

[0071] Table 2

[0072]

[0073] After mixing with the simulated artificial tear solution, the comparative example 1 was in a state of dilution, showing the characteristics of tear dilution. When 0.05% to 0.1% of sodium chloride was added, as in comparative examples 3-8, the mixture with the simulated artificial tear solution could not form a gel. However, the 0.4% pilocarpine hydrochloride in-situ gel added with 0.15% to 0.20% of the ion concentration regulator, such as in examples 2 and 3, could quickly complete the transition from solution to gel after mixing with the simulated artificial tear solution, and had the characteristics of resisting tear dilution. When the ion concentration regulator reached 0.25%, such as in examples 4-5 and example 7, small gel particles appeared after the preparation was stored for a long time, which disappeared after shaking. In addition, it was surprisingly found that the mannitol in the 0.4% pilocarpine hydrochloride in-situ gel could synergistically promote the formation of the gel with the ion concentration regulator, such as in example 1, the addition of 3% mannitol did not achieve gel transition, but in example 2, the same proportion of ion concentration regulator increased the mannitol to 4% to form a gel. When the proportion of mannitol was 3.2% to 4% and the proportion of sodium chloride was 0.15% to 0.2%, the synergistic effect was better, and when the proportion of mannitol was 3.5% and the proportion of sodium chloride was 0.2%, the synergistic effect was the best.

[0074] The same method was used to prepare 1.25% pilocarpine hydrochloride in situ gel according to Table 3:

[0075] Table 3

[0076]

[0077] Comparative Examples 9-12 showed that they were gels at room temperature (not mixed with simulated artificial tears), and became liquid after shaking. When the proportion of deacetylated gellan gum was reduced to 0.4%, as in Examples 11-12, the addition of 0.15%-0.2% of the ionic strength regulator could quickly form a gel after mixing with simulated artificial tears. Further increasing the proportion of ionic strength regulator to 0.25% would result in small gel particles, as in Example 13. When the proportion of deacetylated gellan gum was 0.3%, a strong gel could not be formed. When the proportion of mannitol was 2%-2.5% and the proportion of sodium chloride was 0.15%-0.2%, both good gelation behavior and the requirement for osmotic pressure of ophthalmic preparations could be achieved.

[0078] Examples 16-21

[0079] The prescription amount of drugs and excipients was taken according to the following table, and the osmotic pressure regulator of pilocarpine hydrochloride ion-sensitive gel was screened by the same preparation method as described above. The appropriate osmotic agent was selected based on the comprehensive evaluation of the flow properties of the preparation and the osmotic pressure regulation effect.

[0080] Table 4

[0081]

[0082] The flowability of the preparations of Examples 16-18 was observed. With the increase of the concentration of mannitol, the consistency of the sample was enhanced, indicating that mannitol could increase the consistency of the preparation. The effects of mannitol, PEG400, and glycerol on the preparation were investigated. The results showed that Example 20 with 2.3% PEG400 had a more serious wall-hanging phenomenon, poor flowability, and an osmotic pressure of only 224 mOsmol / kg, which did not meet the requirement for osmotic pressure of ophthalmic preparations. Further increasing the amount of PEG400 would result in a more serious wall-hanging phenomenon, so PEG400 was not suitable as an osmotic pressure regulator for this system. The osmotic pressure of Example 2 with 1.15% glycerol was 302 mOsmol / kg, but the gel strength of this formulation was weak, so it was a second choice as an osmotic pressure regulator.

[0083] Examples 22-26

[0084] The pH of 1.25% pilocarpine hydrochloride ion-sensitive in-situ gel without pH adjuster in the prescription is about 4.8, and the screening of pH adjuster for 1.25% pilocarpine hydrochloride ion-sensitive in-situ gel is carried out. According to the following table, the pH adjustment effect of edetate disodium, sodium hydroxide and tromethamine on the preparation is investigated. The preparation method is changed only by adding the new pH adjuster into the drug-containing solution, and the pH values of the prescriptions listed in Table 5 are measured by a pH meter, without other changes.

[0085] Table 5

[0086]

[0087]

[0088] The pH value of the prescription of Example 22 is 4.33, which is lower than that of Comparative Example 2 (4.85), and 0.1% edetate disodium will make the pH of the preparation lower. The pH of Examples 23-26 is adjusted to about 5.0-5.5, and each prescription is clear and transparent at room temperature. When mixed with simulated artificial tears 40:7 at 34°C, all of them are in a dilute state except Example 25, so tromethamine is the preferred pH adjuster.

[0089] Examples 27-31

[0090] The gelling property of deacetylated gellan gum when compounded with gel adjusters such as sodium alginate and xanthan gum is investigated.

[0091] The deacetylated gellan gum mother liquor is prepared according to the same method as described above.

[0092] Preparation of sodium alginate mother liquor: 1g of sodium alginate is weighed and added to 99g of purified water under stirring at room temperature, and the solution is continuously stirred until it becomes clear. The solution is left to swell fully, and 1% w / w sodium alginate mother liquor is prepared for later use.

[0093] Preparation of xanthan gum mother liquor: 0.8g of xanthan gum is weighed and added to 99.2g of purified water under stirring at room temperature, and the solution is continuously stirred until it is evenly dispersed, and 0.8% w / w xanthan gum mother liquor is prepared for later use.

[0094] The samples with added sodium alginate are prepared according to the prescriptions listed in Table 6, and the preparation method is changed only by adding the new prescription amount of sodium alginate solution into the drug-containing solution, without other changes.

[0095] Table 6

[0096]

[0097]

[0098] Comparative Examples 17-19 were clear and transparent, and failed to form a gel when mixed with simulated artificial tears at a ratio of 40:7. Compared to Examples 4-5 without sodium alginate, the gel particles in Examples 28-29 were improved, indicating that the addition of sodium alginate can improve the hard gel behavior formed after deacetylated gellan gum binds to cations. Example 30 (with calcium chloride) formed irreversible gel clumps immediately upon the addition of sodium alginate, and the same was true after reducing the calcium chloride content to 0.05%, showing greater sensitivity to calcium ion concentration, indicating that the introduction of divalent cation calcium ions is not suitable as an ion concentration regulator for this mixed gel system.

[0099] Samples with added xanthan gum were prepared according to the prescriptions listed in Table 7. The preparation method was the same except that the newly added xanthan gum was added to the drug-containing solution.

[0100] Table 7

[0101]

[0102] As the xanthan gum concentration increased, the sample consistency gradually increased. At 0.3% xanthan gum, a gel formed at room temperature, but the formulation still exhibited poor flowability after shaking. Comparative Example 20 was relatively thin, becoming even thinner after mixing with simulated artificial tears at 34°C (40:7 ratio), and failed to form a gel. Example 31, with the addition of 0.2% sodium chloride, rapidly formed a gel. By adding an appropriate amount of ion concentration regulator to a low-proportion xanthan gum formulation, the gelation properties of the deacetylated gellan gum-xanthan gum complex were adjusted, while simultaneously reducing the deacetylated gellan gum content to 0.4%.

[0103] Experimental Example 1: Measurement of the viscosity of the formulation

[0104] This study simulates the viscosity changes caused by factors such as temperature, shear force, and tear flushing after instilling pilocarpine-containing in-situ gel eye drops into the conjunctival sac. The formulations listed in Table 8 were prepared. Comparative Examples 9, 3, and 32-33 were mixed with simulated artificial tears at volume ratios of 40:0, 40:7, 40:14, 40:21, and 40:28. The viscosity before and after adding the simulated artificial tears was measured within 30 seconds under physiological conditions (34°C) using an Anton Paar CC18 rotational viscometer.

[0105] Table 8

[0106]

[0107] like Figures 2 to 4 As shown in Tables 10-12, the viscosity of Examples 3 and 32-33 increased after contact with tears, and the in-situ gels formed all exhibited shear-thinning non-Newtonian fluid characteristics. According to... Figure 1As shown in Table 9, after contact with tears, the viscosity of Comparative Example 9 first decreased, then increased, and then decreased again, reaching a peak viscosity of 562.2 mPa·s only at a ratio of 40:21. This indicates that the viscosity of Comparative Example 9 was initially at a low level after being instilled into the ocular surface, and then slowly formed a gel with the secretion of tears. Comparative Example 9 required more tears to form a gel, and its gel formation rate was slower. Figure 2 The results in Table 10 show that the viscosity peak of Example 3 was not significantly different from that of Comparative Example 9. However, the addition of 0.2% sodium chloride accelerated the gel formation rate of deacetylated gellan gum, and the viscosity increased immediately upon application to the ocular surface, reaching its peak viscosity at a ratio of 40:14. This indicates that the formulation can form a gel relatively quickly during continuous tear renewal. Figure 3 As shown in Table 11, the viscosity change trend of Example 32 is similar to that of Example 3, reaching a peak viscosity at 40:14, indicating rapid gel formation. Figure 4 As shown in Table 12, Example 33 reached its maximum viscosity and formed a gel fastest at a ratio of 40:7, forming a gel immediately upon application to the ocular surface. The pH and osmotic pressure of Examples 3, 32, and 33 all met the requirements for ophthalmic preparations.

[0108] Table 9

[0109]

[0110]

[0111] Table 10

[0112]

[0113] Table 11

[0114]

[0115] Table 12

[0116]

[0117] Stability test in Experiment Example 2

[0118] The formulations of Examples 3, 12, and 32-33 were prepared and dispensed into transparent, capped glass bottles for stability testing.

[0119] High-temperature test: Samples were taken at 60°C at 0, 5, and 10 days. The appearance of the formulations in Examples 3, 12, and 32-33 was observed, and changes in pH, osmotic pressure, and content were measured. If the content of the test sample was lower than the specified limit, the test was conducted at 40°C using the same method. If there was no significant change at 60°C, the 40°C test was not performed.

[0120] Low temperature test: Samples were taken at 0, 5 and 10 days at 4℃ to observe the appearance of the formulations in Example 3, Example 12 and Example 32-33, and to measure the changes in their pH, osmotic pressure and content.

[0121] Light test: The samples were placed in a light incubator and placed under an illuminance of 4500 lx ± 500 lx for 10 days. The various indicators of the formulations listed in Example 3, Example 12, and Examples 32-33 were examined.

[0122] The stability results under various conditions are shown in Tables 13 and 14. The formulations under all conditions were clear and transparent. At high temperatures, the fluidity of the formulations was close to that of an aqueous solution, and they returned to their original state at room temperature. The osmotic pressure of all formulations showed no significant change, ranging from 260 to 330 mOsmol / kg. Under both normal and low-temperature conditions, the content changes met the requirements, remaining between 98% and 102%. When the temperature reached 40°C, the pH of the formulation decreased; when the temperature further reached 60°C, the pH of all formulations was below 5. Therefore, the formulations containing pilocarpine hydrochloride of this invention should be avoided at high temperatures.

[0123] Table 13

[0124]

[0125] Table 14

[0126]

[0127]

[0128] Experimental Example 3: In vitro dissolution rate test

[0129] The dissolution rate and cumulative release percentage were determined using a membrane-free dissolution method. The formulation containing pilocarpine hydrochloride of this invention was prepared according to the table below. 2 g of the formula listed in Table 15 was accurately weighed, and 350 μL of simulated artificial tears was added. The mixture was quickly mixed, accurately weighed, and recorded. The mixture was placed in an air bath shaker (34°C, 120 r / min), and 2 mL of simulated artificial tears preheated to 34°C was slowly added. All release media were collected at different time points, quickly weighed, and recorded. After each collection of release media, an equal volume of fresh simulated artificial tears preheated to 34°C was added, and the mixture was placed back in the air bath shaker. This process was repeated. The cumulative dissolution amount of the gel was plotted against time to obtain the gel dissolution curve. Simultaneously, the content of the collected release media was determined, and the cumulative release percentage was calculated.

[0130] Table 15

[0131]

[0132] like Figure 5As shown in Table 16, Examples 7 and 33, containing 0.4% (w / w) deacetylated gellan gum, demonstrated good ability to inhibit tear erosion. Under simulated tear flushing conditions, approximately 60% of the matrix in Examples 7 and 32-33 remained undissolved after 24 hours, effectively prolonging the drug's retention time in the eye. Figure 5 and Figure 6 The gel dissolution rate was relatively fast within the first 7 hours, and the drug release was also relatively fast within that time. After 7 hours, the gel dissolution rate slowed down, and the drug release rate also slowed down. Among them, the release rate of Example 7 was significantly faster than that of Examples 32 and 33. The in vitro dissolution behavior and in vitro drug release behavior of the pilocarpine hydrochloride in situ gels of Examples 7, 32-33 of the present invention, measured using the membrane-free method, were consistent with the in vitro drug release behavior.

[0133] Table 16

[0134]

[0135] Experimental Example 4: In vitro release test

[0136] A 1.25% pilocarpine hydrochloride eye drop solution was prepared as a control, based on the formulation of the commercially available formulation Vuity. The in vitro drug release of the control solution, Comparative Example 9, and Examples 32-33 was measured. The cumulative release percentage of pilocarpine hydrochloride was determined using the dialysis bag method.

[0137] Using 30 mL of simulated artificial tears (34°C) as the diffusion medium, 1 mL of the control solution, Comparative Example 9, and Examples 32-33 were transferred into pre-treated dialysis bags. The constant-temperature shaker speed was adjusted to 120 r / min, and the temperature was controlled at 34°C. At specific time points, 5 mL samples were taken, and isothermal and equal volumes of simulated artificial tears were added promptly. After filtering the above samples through a 0.22 μm filter, the drug content was determined by HPLC, and the cumulative drug release was calculated.

[0138] Release results measured using the dialysis bag method are as follows: Figure 7 As shown in Table 17, the release rate of the 1.25% pilocarpine hydrochloride control solution exceeded 90% within 1 hour, while the pilocarpine hydrochloride in-situ gel formulations of Examples 32 and 33 of this invention maintained drug release for more than 4 hours. Compared with the pilocarpine hydrochloride control solution, the pilocarpine hydrochloride in-situ gel formulations of this invention exhibited a sustained-release effect. Compared with Comparative Example 9 (containing only 0.6% gellan gum in the formulation), Example 33, with the addition of 0.2% sodium chloride and a reduction in the gellan gum content to 0.4%, achieved the same sustained-release rate. The similar release rates of Examples 32 and 33 indicate that the release behavior of the two specifications of the pilocarpine hydrochloride in-situ gel formulations of this invention is consistent.

[0139] Table 17

[0140]

Claims

1. An ophthalmic ion-sensitive in-situ gel formulation, characterized in that, The ion-sensitive in-situ gel formulation includes: The active pharmaceutical ingredient is pilocarpine hydrochloride. The gel matrix is ​​selected from deacetylated gellan gum, sodium alginate, xanthan gum, hydroxypropyl methylcellulose, or polyethylene glycol, or a combination of two or more of these; and An ion concentration regulator, wherein the ion concentration regulator comprises 0.15% to 0.25% w / w of the gelling agent by weight, and the ion concentration regulator includes sodium chloride, potassium chloride, or calcium chloride, or a combination of two or more thereof. Preferably, the gel matrix is ​​selected from deacetylated gellan gum, or a combination of deacetylated gellan gum and sodium alginate, a combination of deacetylated gellan gum and xanthan gum, a combination of deacetylated gellan gum and hydroxypropyl methylcellulose, or a combination of deacetylated gellan gum and polyethylene glycol.

2. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The preferred ion concentration regulator is sodium chloride.

3. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The ion concentration regulator, based on the weight of the gel, preferably comprises 0.15% w / w, 0.16% w / w, 0.17% w / w, 0.18% w / w, 0.19% w / w, 0.2% w / w, and 0.25% w / w, more preferably 0.15% w / w, 0.2% w / w, and 0.25% w / w, and most preferably 0.2% w / w.

4. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The active ingredient, pilocarpine hydrochloride, has a content of 0.3% to 1.5% w / w, preferably 0.4% w / w or 1.25% w / w.

5. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The gel matrix, based on the weight of the gelling agent, accounts for 0.2% to 0.8% w / w, preferably 0.3% w / w, 0.4% w / w, 0.45% w / w, 0.5% w / w, 0.6% w / w, 0.7% w / w, and more preferably 0.4% w / w and 0.6% w / w.

6. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The ion-sensitive in-situ gel formulation further includes an osmotic pressure regulator, which is selected from one or more of mannitol, glycerol, and polyethylene glycol 400.

7. The ophthalmic ion-sensitive in-situ gel formulation according to claim 6, characterized in that, The osmotic pressure regulator, based on the weight of the gel, accounts for 1% to 5% w / w, preferably 1.1% to 4% w / w, more preferably 1.15% w / w, 2% w / w, 2.3% w / w, 2.5% w / w, 3% w / w, 3.2% w / w, 3.5% w / w, 4% w / w, and most preferably 2% w / w or 3.5% w / w.

8. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The ion-sensitive in-situ gel formulation further includes a pH adjuster, which is selected from one or more of disodium edetate, hydrochloric acid, sodium hydroxide, and tromethamine.

9. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The ion-sensitive in-situ gel formulation also includes a preservative, which is selected from one or more of benzalkonium chloride, methylparaben, chlorobutanol, and potassium sorbate.

10. The ophthalmic ion-sensitive in-situ gel formulation according to claim 9, characterized in that, The preservative, based on the weight of the gelling agent, accounts for 0.001% to 0.5% w / w, preferably 0.005% to 0.01% w / w, more preferably 0.0075% w / w or 0.01% w / w, and most preferably 0.0075% w / w.

11. The ophthalmic ion-sensitive in-situ gel formulation according to claim 1, characterized in that, The gel formulation also includes an appropriate amount of water.

12. The ophthalmic ion-sensitive in-situ gel formulation according to any one of claims 1 to 10, characterized in that, The ion-sensitive in-situ gel formulation comprises: pilocarpine hydrochloride 0.3%–1.5% w / w, deacetylated gellan gum 0.2%–0.8% w / w, sodium chloride 0.15%–0.20% w / w, mannitol 1%–5% w / w, benzalkonium chloride 0.001%–0.5% w / w, tromethorphan 0.001%–0.05% w / w, and purified water.

13. The ophthalmic ion-sensitive in-situ gel formulation according to any one of claims 1 to 10, characterized in that, The ion-sensitive in-situ gel formulation comprises 0.3%–1.5% w / w pilocarpine hydrochloride, 0.2%–0.8% w / w deacetylated gellan gum, 0.15%–0.20% w / w sodium chloride, 1%–5% w / w mannitol, 0.001%–0.5% w / w benzalkonium chloride, and purified water.

14. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12 or 13, characterized in that, The content of pilocarpine hydrochloride is preferably 0.4% w / w or 1.25% w / w.

15. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12 or 13, characterized in that, The deacetylated gellan gel, by weight of the gelling agent, preferably comprises 0.3% w / w, 0.4% w / w, 0.45% w / w, 0.5% w / w, 0.6% w / w, or 0.7% w / w, more preferably 0.4% w / w or 0.6% w / w.

16. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12 or 13, characterized in that, The sodium chloride content, based on the weight of the gelling agent, is preferably 0.15% w / w, 0.16% w / w, 0.17% w / w, 0.18% w / w, 0.19% w / w, or 0.2% w / w, more preferably 0.15% w / w or 0.2% w / w, and most preferably 0.2% w / w.

17. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12 or 13, characterized in that, The mannitol, by weight of the gelling agent, preferably comprises 2% to 4% w / w, more preferably 2% w / w, 2.3% w / w, 2.5% w / w, 3% w / w, 3.2% w / w, 3.5% w / w, or 4% w / w, and most preferably 2% w / w, 3.2% w / w, or 3.5% w / w.

18. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12 or 13, characterized in that, The benzalkonium chloride content, based on the weight of the gelling agent, is preferably 0.005% to 0.01% w / w, more preferably 0.0075% w / w.

19. The ophthalmic ion-sensitive in-situ gel formulation according to claim 12, characterized in that, The tromethamine, by weight of the gelling agent, is preferably present in a concentration of 0.01% w / w or 0.002% w / w.

20. The ophthalmic ion-sensitive in-situ gel formulation according to any one of claims 12 to 19, characterized in that, When mannitol is preferably 3.2% to 4% w / w by weight of the gelling agent, sodium chloride is preferably 0.15% to 0.2% w / w by weight of the gelling agent. When mannitol is most preferably 3.5% w / w by weight of the gelling agent, sodium chloride is 0.2% w / w by weight of the gelling agent.

21. The ophthalmic ion-sensitive in-situ gel formulation according to any one of claims 1 to 20, characterized in that, The pH range of the ophthalmic preparation is 4.0 to 6.0, preferably 4.5 to 5.5, and more preferably 5.0 to 5.

5.

22. The use of the ophthalmic ion-sensitive in-situ gel formulation according to any one of claims 1 to 21 in the preparation of a medicament for treating ophthalmic diseases, wherein the ophthalmic diseases are preferably hyperopia, presbyopia, or glaucoma.

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