Preparation method and application of controlled-release pharmaceutical composition

Abstract

The invention provides a preparation method and application of a controlled-release pharmaceutical composition. Chitosan temperature-sensitive hydrogel and carboxymethyl-beta-cyclodextrin are used for improving the drug loading capacity, solubility and bioavailability of steroid drugs, especially ethinyloestradiol. Compared with a pure ethinylestradiol / carboxymethyl-beta-cyclodextrin inclusion compound, the controlled-release pharmaceutical composition provided by the invention has the advantages that the action time of the medicine can be prolonged, the stability of ethinylestradiol is improved, and the controlled-release capability of the medicine is enhanced. The preparation method disclosed by the invention is simple and convenient to operate and short in gelation time, and has a wide market application prospect.

Description

Technical Field

[0001] The invention belongs to the field of medicine and relates to a preparation method of a controlled-release pharmaceutical composition and application thereof. Background Art

[0002] Ethinyl estradiol is an estrogen drug used to supplement estrogen deficiency and treat diseases such as female gonadal dysfunction, amenorrhea and menopausal syndrome. It is mainly used as an ovulation inhibitor and contraceptive, but its poor water solubility limits its bioavailability. There are few injection formulations designed for ethinyl estradiol, and existing contraceptive formulations (such as tablets) lack long-term sustained-release effects when administered orally.

[0003] At present, although there are reports on using common cyclodextrins such as hydroxypropyl-β-cyclodextrin to solubilize ethinyl estradiol, the solubilization effect is limited and a long-term release effect cannot be achieved.

[0004] Therefore, improving the drug loading, solubility, bioavailability, stability, prolonging the drug action time, and enhancing the drug controlled release ability of ethinyl estradiol are issues that need to be addressed urgently. Summary of the invention

[0005] In view of this, in order to make up for the deficiencies of the prior art, the present invention is proposed.

[0006] The first aspect of the present invention provides a controlled release pharmaceutical composition, which comprises a steroid drug, a cyclodextrin solubilizer, and a controlled release carrier.

[0007] In the present invention, a pharmaceutical composition refers to any composition comprising at least one biologically active agent. When used herein, the term "pharmaceutical composition" also refers to a composition comprising an active pharmaceutical ingredient to be delivered to a subject, for example to achieve a therapeutic, preventive, anti- or prognostic effect.

[0008] In the present invention, controlled release refers to the ability to maintain the blood drug concentration within the effective concentration range for a long period of time.

[0009] Furthermore, the controlled release carrier includes a thermosensitive hydrogel.

[0010] Furthermore, the steroid drug can form an inclusion compound with the cyclodextrin solubilizing agent.

[0011] In the present invention, inclusion compound refers to a unique form of complex formed by a guest molecule being fully or partially included in the molecular cavity of another substance. This inclusion compound is composed of a guest molecule and a host molecule. The host molecule generally has a large cavity structure, which is sufficient to accommodate the guest molecule and form a molecular microcapsule. Inclusion compounds are divided into tubular, cage-type, and layered inclusion compounds according to the geometric shape of the host molecule cavity. After the guest molecule and the host molecule form an inclusion compound through van der Waals force, the solubility increases, the stability is improved, the liquid drug can be powdered, the volatile components can be prevented from volatilizing, the bad smell or taste of the drug can be covered, the release rate can be adjusted, the bioavailability of the drug can be improved, and the irritation and toxic side effects of the drug can be reduced. The size and shape of the guest molecule should be adapted to the cavity of the host molecule to obtain an inclusion compound with stable properties. If the guest molecule is too large, it is difficult to embed into the cavity of the host molecule, and only the side chain is included, and the properties are unstable. If the guest molecule is too small, it cannot fill the cavity, the inclusion force is weak, and it is easy to enter and exit freely and fall off, and the inclusion is unstable. The cavity of the main molecular material cyclodextrin is a hydrophobic area, so hydrophobic or non-dissociated drugs can easily enter and be included, and it is easy to form a stable inclusion complex. Polar drugs can be embedded in the hydrophilic area at the mouth of the cavity and can form hydrogen bonds with the hydroxyl groups of cyclodextrin. Drugs that can associate themselves often dissociate first and then enter the cavity of cyclodextrin.

[0012] Furthermore, the steroid drugs include glucocorticoids, mineralocorticoids, and sex hormones.

[0013] Furthermore, the steroid drug is selected from sex hormones.

[0014] Furthermore, the sex hormones include ethinyl estradiol, estradiol, progesterone, medroxyprogesterone, methyltestosterone, testosterone undecanoate, and testosterone propionate.

[0015] Furthermore, the sex hormone is selected from ethinyl estradiol.

[0016] Furthermore, the thermosensitive hydrogel includes chitosan thermosensitive hydrogel, Pluronic F127 hydrogel, PDLLA-PEG-PDLLA hydrogel, PLGA-PEG-PLGA hydrogel, and Mebiol® Gel hydrogel.

[0017] Furthermore, the thermosensitive hydrogel is selected from chitosan thermosensitive hydrogel.

[0018] Furthermore, the chitosan thermosensitive hydrogel comprises chitosan and sodium β-glycerophosphate.

[0019] Furthermore, the sodium β-glycerophosphate is pentahydrate.

[0020] Furthermore, the cyclodextrin solubilizing agent includes cyclodextrin or its derivatives.

[0021] Furthermore, the cyclodextrin includes α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

[0022] Furthermore, the cyclodextrin solubilizing agent is a β-cyclodextrin derivative.

[0023] Furthermore, the β-cyclodextrin derivative is carboxymethyl-β-cyclodextrin.

[0024] Furthermore, the controlled-release pharmaceutical composition comprises chitosan thermosensitive hydrogel and ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound.

[0025] Furthermore, the controlled-release pharmaceutical composition also includes pharmaceutically acceptable excipients other than the cyclodextrin solubilizer.

[0026] Furthermore, the pharmaceutically acceptable excipients include, but are not limited to, diluents, excipients, fillers, binders, wetting agents, disintegrants, emulsifiers, solubilizers, osmotic pressure regulators, lubricants, surfactants, coating materials, colorants, pH regulators, antioxidants or antibacterial agents.

[0027] Further, the diluent includes but is not limited to lactose, sodium chloride, glucose, urea, starch, water, etc. The binder includes but is not limited to starch, pregelatinized starch, dextrin, maltodextrin, sucrose, gum arabic, gelatin, methylcellulose, carboxymethylcellulose, alginic acid and alginate, xanthan gum, hydroxypropyl cellulose, etc. The surfactant includes but is not limited to sodium lauryl sulfate, stearic acid monoglyceride, hexadecanol, etc. The lubricant includes but is not limited to zinc stearate, talc, calcium and magnesium stearate, polyethylene glycol, polyoxyethylene monostearate, monolauric sucrose acid ester, magnesium lauryl sulfate, etc. The filler includes but is not limited to mannitol, xylitol, sorbitol, maltose, glucose, lactose, sucrose, dextrin, starch, etc. The disintegrant includes but is not limited to cross-linked vinyl pyrrolidone, sodium carboxymethyl starch, low-substituted hydroxypropyl methyl, cross-linked sodium carboxymethyl cellulose, soybean polysaccharide, etc.

[0028] Furthermore, the controlled-release pharmaceutical composition is administered in a suitable dosage form.

[0029] Furthermore, the dosage form includes a dosage form for enteral administration and a dosage form for parenteral administration.

[0030] Furthermore, the non-intestinal administration dosage forms include injection dosage forms, respiratory tract administration dosage forms, cavity administration dosage forms, mucosal administration dosage forms, and skin administration dosage forms.

[0031] Furthermore, the parenteral dosage form is selected from an injection dosage form.

[0032] Furthermore, the injectable dosage form includes intravenous injection, intramuscular injection, subcutaneous injection, intradermal injection or intracavitary injection.

[0033] The second aspect of the present invention provides a method for preparing the controlled release pharmaceutical composition according to the first aspect of the present invention, the method comprising mixing a controlled release carrier with a drug / cyclodextrin solubilizer inclusion complex.

[0034] Furthermore, the method comprises mixing the chitosan thermosensitive hydrogel with the ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex.

[0035] Furthermore, the method comprises immersing the chitosan thermosensitive hydrogel in the inclusion complex supernatant to obtain the drug-loaded hydrogel.

[0036] Furthermore, the chitosan thermosensitive hydrogel is in a freeze-dried state.

[0037] Furthermore, the method also includes a method for preparing an ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex, and the steps of the preparation method include mixing ethinyl estradiol with carboxymethyl-β-cyclodextrin.

[0038] In the present invention, the preparation method of the ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound includes a saturated aqueous solution method, an embedding method, a microwave method, a co-grinding method, an ultrasonic method, and a suspension method.

[0039] In the present invention, the saturated aqueous solution method is also called coprecipitation or recrystallization method. First, β-cyclodextrin is made into a saturated aqueous solution, and the guest molecule drug is added. For water-insoluble drugs, they can be dissolved in a small amount of organic solvent first, and then injected into the saturated aqueous solution of β-cyclodextrin, and stirred until they become inclusion compounds. The inclusion compound is precipitated by appropriate means (such as refrigeration, concentration, adding precipitants, etc.), and the obtained solid inclusion compound is filtered, washed, and dried.

[0040] In the present invention, the co-grinding method refers to taking β-cyclodextrin and adding 2 to 5 times the amount of water to grind evenly, adding the guest molecule drug (for those that are poorly soluble in water, first dissolve the guest molecule drug in a small amount of appropriate solvent), placing it in a grinder and mixing it thoroughly to grind it into a paste, drying it at low temperature, washing it with an appropriate solvent, and then drying it to obtain an inclusion compound.

[0041] In the present invention, the ultrasonic method refers to adding the substance to the saturated solution of the wall material, selecting a suitable ultrasonic intensity, using an ultrasonic crusher or an ultrasonic cleaner to ultrasonicate for a certain period of time at a set temperature, placing it in a refrigerator for refrigeration and filtering to obtain a white powder, washing the filter cake with a small amount of solvent, drying it in an oven, and crushing it to obtain the inclusion compound.

[0042] Furthermore, the preparation method is selected from a saturated aqueous solution method.

[0043] Furthermore, the saturated aqueous solution method comprises mixing a carboxymethyl-β-cyclodextrin aqueous solution with an ethinyl estradiol organic solution.

[0044] Furthermore, the carboxymethyl-β-cyclodextrin aqueous solution is a saturated aqueous solution.

[0045] Furthermore, the molar usage ratio of ethinyl estradiol to carboxymethyl-β-cyclodextrin is 1:1 to 100:1.

[0046] Furthermore, the molar usage ratio of ethinyl estradiol and carboxymethyl-β-cyclodextrin is 1:1.

[0047] In the present invention, the organic solvent in the organic solution can include 10 categories according to its chemical structure: ① aromatic hydrocarbons: benzene, toluene, xylene, etc.; ② aliphatic hydrocarbons: pentane, hexane, octane, etc.; ③ alicyclic hydrocarbons: cyclohexane, cyclohexanone, toluene cyclohexanone, etc.; ④ halogenated hydrocarbons: chlorobenzene, dichlorobenzene, dichloromethane, etc.; ⑤ alcohols: methanol, ethanol, isopropanol, etc.; ⑥ ethers: ethyl ether, propylene oxide, etc.; ⑦ esters: methyl acetate, ethyl acetate, propyl acetate, etc.; ⑧ ketones: acetone, methyl butyl ketone, methyl isobutyl ketone, etc.; ⑨ glycol derivatives: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, etc.; ⑩ others: acetonitrile, pyridine, phenol, etc.

[0048] Furthermore, the ethinyl estradiol organic solution includes ethinyl estradiol methanol solution, ethinyl estradiol ethanol solution and ethinyl estradiol isopropanol solution.

[0049] Furthermore, the ethinyl estradiol organic solution is selected from ethinyl estradiol ethanol solution.

[0050] Furthermore, the volume ratio of the aqueous solution to the organic solution is 5:1 to 20:1.

[0051] Furthermore, the volume ratio of the aqueous solution to the organic solution is 10:1.

[0052] Furthermore, the molar concentration of the carboxymethyl-β-cyclodextrin is 0.04 mol / L.

[0053] Furthermore, the molar concentration of ethinyl estradiol is 0.4 mol / L.

[0054] Furthermore, the preparation method comprises mixing a saturated aqueous solution of carboxymethyl-β-cyclodextrin and an ethanol solution of ethinyl estradiol at a volume ratio of 10:1, wherein the solute amounts of ethinyl estradiol and carboxymethyl-β-cyclodextrin are equimolar, and stirring them for later use.

[0055] Furthermore, the stirring temperature is 35°C to 50°C.

[0056] Furthermore, the stirring temperature is 40°C.

[0057] Furthermore, the stirring time is 30 min to 2 h.

[0058] Furthermore, the stirring time is 1 h.

[0059] Furthermore, after stirring, the mixture was left at room temperature and continued to be stirred.

[0060] Further, the stirring time is continued for 2 h to 5 h.

[0061] After stirring, the mixture was placed at room temperature and stirred for 3 h.

[0062] Further, stir and refrigerate.

[0063] Further, refrigerate and dry for later use.

[0064] Furthermore, the drying method is freeze drying.

[0065] Furthermore, the method also includes a method for preparing chitosan / β-sodium glycerophosphate hydrogel, and the steps of the preparation method include mixing a chitosan solution with a β-sodium glycerophosphate solution.

[0066] Furthermore, the chitosan solution is used at a concentration of 1% (w / v) to 5% (w / v).

[0067] Furthermore, the chitosan solution is used at a concentration of 2% (w / v).

[0068] Furthermore, the use concentration of the β-sodium glycerophosphate solution is 50% (w / v) to 200% (w / v).

[0069] Furthermore, the use concentration of the β-sodium glycerophosphate solution is 100% (w / v).

[0070] Furthermore, the volume ratio of the chitosan solution to the sodium β-glycerophosphate solution is 10:1 to 1:1.

[0071] Furthermore, the volume ratio of the chitosan solution to the β-sodium glycerophosphate solution is 1:1.

[0072] Furthermore, the chitosan is dissolved using hydrochloric acid.

[0073] Furthermore, the sodium β-glycerophosphate is dissolved in distilled water.

[0074] Furthermore, the concentration of hydrochloric acid used is 0.1 mol L -1 .

[0075] Furthermore, the preparation method comprises dissolving chitosan in hydrochloric acid to form a 2% (w / v) solution, dissolving β-sodium glycerophosphate pentahydrate in distilled water to form a 100% (w / v) solution, cooling, adding the β-sodium glycerophosphate solution dropwise to the chitosan solution while stirring, stirring in an ice bath, and drying for later use.

[0076] Furthermore, the stirring time in the ice bath was 10 min.

[0077] Furthermore, the method also includes a method for preparing carboxymethyl-β-cyclodextrin, which includes synthesizing carboxymethyl-β-cyclodextrin using β-cyclodextrin and chloroacetic acid under alkaline conditions.

[0078] Furthermore, the method includes mixing a chitosan solution with a concentration of 2% (w / v) and a 100% (w / v) sodium β-glycerophosphate solution at a volume ratio of 1:1 to obtain a chitosan / sodium β-glycerophosphate hydrogel, mixing a saturated aqueous solution of carboxymethyl-β-cyclodextrin and an ethinyl estradiol ethanol solution at a volume ratio of 10:1 to obtain an ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex, wherein the solute usage amounts of ethinyl estradiol and carboxymethyl-β-cyclodextrin are equimolar, and mixing the chitosan / sodium β-glycerophosphate hydrogel and the ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex.

[0079] The third aspect of the present invention provides any of the following applications:

[0080] (1) Use of the controlled release pharmaceutical composition according to the first aspect of the present invention in the preparation of a controlled release injection;

[0081] (2) Use of the controlled-release pharmaceutical composition described in the first aspect of the present invention in the preparation of an estrogen supplement drug;

[0082] (3) Use of the controlled-release pharmaceutical composition according to the first aspect of the present invention in the preparation of contraceptive drugs;

[0083] (4) Use of the controlled-release pharmaceutical composition according to the first aspect of the present invention in improving the bioavailability of drugs;

[0084] (5) Use of the controlled-release pharmaceutical composition according to the first aspect of the present invention in increasing the drug loading of ethinyl estradiol;

[0085] (6) Use of the controlled release pharmaceutical composition according to the first aspect of the present invention in improving the solubility of hydrophobic drugs.

[0086] The present invention has the following advantages and beneficial effects:

[0087] The present invention provides a preparation method and application of a controlled-release pharmaceutical composition. The present invention uses chitosan thermosensitive hydrogel and carboxymethyl-β-cyclodextrin to improve the drug loading, solubility and bioavailability of steroid drugs, especially ethinyl estradiol. Compared with a simple ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound, the controlled-release pharmaceutical composition provided by the present invention has the advantages of being able to prolong the drug action time, improve the stability of ethinyl estradiol, and enhance the drug controlled release ability. The preparation method of the present invention is simple to operate, has a short gelation time, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 The present invention is a flow chart for the preparation of a controlled-release pharmaceutical composition, wherein (A) is a flow chart for the preparation of an inclusion compound; (B) is a flow chart for the preparation of a chitosan / β-sodium glycerophosphate hydrogel; and (C) is a schematic diagram of the action of ethinyl estradiol.

[0089] Figure 2 The figures are the synthesis and characterization results of chitosan / sodium β-glycerophosphate thermosensitive hydrogel loaded with ethinyl estradiol, wherein (A) is the infrared image of β-cyclodextrin, carboxymethyl-β-cyclodextrin, ethinyl estradiol and inclusion complex; (B) is the infrared image of chitosan, sodium β-glycerophosphate, chitosan / sodium β-glycerophosphate hydrogel and ethinyl estradiol inclusion complex / chitosan / sodium β-glycerophosphate hydrogel; (C) is the XRD spectrum of sodium β-glycerophosphate and chitosan / sodium β-glycerophosphate hydrogel; (D) is the UV spectrum of ethinyl estradiol; (E) is the UV spectrum of the inclusion complex; (F) is the calibration curve.

[0090] Figure 3 These are the results of the study on the sol-gel transition behavior and injectability of hydrogels, where (A) is a diagram of the gelation process; (B) is a diagram of the viscosity results at 25, 30, 34, 35, 36, and 37°C; (C) is a diagram of the injectability study results; and (D) is a picture of the solution gel transformation.

[0091] Figure 4 These are the results of hydrogel swelling characteristics and porosity analysis, where (A) is the swelling rate result of blank hydrogel; (B) is the swelling rate result of drug-loaded hydrogel; (C) is the porosity result of blank hydrogel and drug-loaded hydrogel.

[0092] Figure 5 Figure 2 is a graph showing the results of in vitro degradation and cytotoxicity analysis, where (A) shows the degradation rate of the hydrogel in PBS and lysozyme in PBS; (B) shows the cell viability at 24 and 48 hours after adding different concentrations of hydrogel extracts.

[0093] Figure 6 Different addition amount (A) Figure 5mg, (B) Fig.10 Figure 20 shows the cumulative release efficiency of ethinyl estradiol in (A) 20 mg, (B) 40 mg, (C) 60 mg, (D) 80 mg, and (G) 100 mg, respectively.

[0094] Figure 7 This is a graph showing the effect of carboxymethyl-β-cyclodextrin (CM-β-CD) on improving the water solubility of ethinyl estradiol (EE) and its dispersion effect on thermosensitive hydrogel.

[0095] Figure 8 This is the result diagram showing that CM-β-CD can significantly improve the dispersion of EE in gel.

[0096] Fig. 9 It is a comparative data result graph of the sustained release ability of the CM-β-CD / EE inclusion complex containing thermosensitive hydrogel and the CM-β-CD / EE inclusion complex without thermosensitive hydrogel, wherein (A) is the release curve of ethinyl estradiol (EE) in β-CD / EE and CM-β-CD / EE; (B) is the release curve of ethinyl estradiol (EE) in the thermosensitive hydrogel with a drug loading of 20 mg in the present application.

[0097] Fig.10 This is a comparison chart of drug dispersibility and hydrogel stability. DETAILED DESCRIPTION

[0098] The disclosure above generally describes the present invention. A more complete understanding can be obtained with reference to the following specific embodiments. The purpose of describing these embodiments is merely for illustration and is not intended to limit the scope of the present invention. Form changes and equivalent substitutions are considered to be circumstances that may suggest or confer convenience. Although specific terms are used in this article, the purpose of these terms is descriptive rather than limiting.

[0099] Example 1 Preparation, characterization and functional verification of the composite system of chitosan-based thermosensitive hydrogel and / ethinylestradiol carboxymethyl-β-cyclodextrin inclusion complex

[0100] 1. Experimental Materials

[0101] Chitosan (100–200 mPa·s, deacetylation ≥95%) was purchased from Shanghai McLean Biochemical Technology Co., Ltd. Dialysis bags (14,000 KDa), lysozyme (egg white, 20,000 u mg -1) and β-cyclodextrin (β-CD) were purchased from Shanghai Chemical Reagent Purchasing and Supply Station (Shanghai, China). Sodium β-glycerophosphate was provided by Shanghai Yien Chemical Technology Co., Ltd. Anhydrous ethanol (AR) was purchased from Tianjin Fuyu Fine Chemical Co., Ltd. (Tianjin, China). Sodium chloroacetate (AR, 98.0%) and sodium hydroxide (AR) were from Tianjin Fuyu Fine Chemical Co., Ltd. (Tianjin, China). All reagents and solvents were used in accordance with safety requirements without any labeling and no further purification was required. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltriazolium bromide (MTT, BR, 98%) was purchased from Nanjing Dulai Biotechnology Co., Ltd. (Nanjing, China).

[0102] 2. Experimental methods and results

[0103] 1. Experimental methods

[0104] (1) Synthesis of β-cyclodextrin derivative - carboxymethyl-β-cyclodextrin

[0105] Carboxymethyl-β-cyclodextrin was synthesized using β-cyclodextrin and chloroacetic acid under alkaline conditions. The synthesis process is as follows: 1.0 g of β-cyclodextrin was dissolved in a mixture of 10.0 mL of deionized water and 0.1 g of sodium hydroxide to prepare an alkaline β-cyclodextrin solution. The solution was stirred at 60°C for about 20 minutes until it was completely dissolved. Then, 0.31 g of sodium chloroacetate was dissolved in 10.0 mL of deionized water and added dropwise to the β-cyclodextrin solution within 20 minutes. The mixture was stirred at 70°C for 4 hours. Then, the pH value was adjusted to 6-7, and ethanol was added to precipitate the product. The suspension was frozen at 4°C overnight to ensure complete precipitation. Finally, the reaction solution was filtered under reduced pressure, and the filter cake was dried in an oven at 60°C to obtain the finished product.

[0106] (2) Preparation of ethinyl estradiol / carboxymethyl-β-cyclodextrin

[0107] There are several methods for preparing cyclodextrin inclusion compounds, including saturated aqueous solution method (coprecipitation or recrystallization method), embedding method, microwave method, co-grinding method, ultrasound method and suspension method. Figure 1 As shown in (A), this experiment used the saturated aqueous solution method. Briefly, equimolar amounts of carboxymethyl-β-cyclodextrin (0.0004 mol) and ethinyl estradiol (0.0004 mol) were dissolved in 10.0 mL of deionized water and 1.0 mL of ethanol, respectively. The two solutions were combined and stirred at 40 °C for 1 h, and then stirred at room temperature for another 3 h. Afterwards, the mixture was refrigerated at 4 °C for 12 h, filtered, and the filtrate was freeze-dried for 12 h to obtain a white solid powder product.

[0108] (3) Preparation of chitosan / sodium β-glycerophosphate hydrogel and ethinyl estradiol inclusion complex / chitosan / sodium β-glycerophosphate hydrogel:

[0109] like Figure 1 (B) As shown. To prepare the hydrogel, chitosan was first dissolved in 0.1 mol L -1 HCl solution to obtain a 2% (w / v) chitosan solution. The solution was stirred for 2 h until it was completely dissolved. Meanwhile, sodium β-glycerophosphate pentahydrate was dissolved in distilled water to prepare 1 g mL -1 Sodium β-glycerophosphate solution. Both solutions were then cooled at 4 °C for 20 min. The sodium β-glycerophosphate solution was added dropwise to the chitosan solution while stirring, followed by stirring in an ice bath for 10 min. This process resulted in the formation of chitosan / sodium β-glycerophosphate hydrogel. The hydrogel was then freeze-dried in a freeze dryer to obtain a freeze-dried hydrogel. To prepare the drug-loaded hydrogel, the dried hydrogel sample was immersed in the inclusion complex supernatant. Once the supernatant was completely absorbed, the drug-loaded hydrogel was obtained. Figure 1 (C) is a schematic diagram of the action of ethinyl estradiol.

[0110] (4) Morphological observation

[0111] XRD is used to characterize the crystal structure and its changes.

[0112] (5) FTIR test

[0113] The hydrogel samples incubated at 37 °C were frozen in a -30 °C refrigerator overnight and freeze-dried using a freeze dryer. The cyclodextrin derivatives and inclusion complexes as well as the hydrogel and drug-loaded hydrogel samples were fully mixed with KBr and compressed into tablets. The samples were analyzed by infrared and the wavelength was 4000–400 cm -1 The test was carried out in the spectral range.

[0114] (6) In vitro cytotoxicity test

[0115] The biosafety of ethinylestradiol inclusion complex / chitosan / sodium β-glycerophosphate hydrogels was examined by evaluating cell viability in vitro using the MTT assay. The freeze-dried hydrogels were sterilized and extracted with saline solution according to ISO 10993-5. The extracts were incubated at different concentrations (0, 40, 80, 120, and 160 mg L -1). Cytotoxicity assays were performed with these extracts. In a 96-well plate, 104 fibroblasts (L929) were placed in each well and cultured for 24 h (5% CO2 pressure, 98% humidity, 37°C). The cells were divided into two groups: (1) negative control (L929 cells without extract) and (2) positive control (L929 cells in culture medium containing hydrogel extract). The cells were cultured for 24 or 48 h. At the end of the incubation, 20 μL of 5 mg mL -1 After 4 hours of incubation, all liquid was carefully removed and 150 μL of dimethyl sulfoxide was added to dissolve the formate hydrazide crystals. The plate was then shaken for 15 seconds to ensure that the precipitate was completely dissolved. Finally, the absorbance at 490 nm was measured using an enzyme marker. Cell viability was calculated according to formula (a).

[0116] (a)

[0117] (7) Study on swelling, viscosity, porosity and degradation of hydrogels

[0118] The swelling properties of the hydrogel in PBS (pH=7.4) solution were measured by gravimetric method. The swelling capacity of the hydrogel was evaluated by comparing the mass difference before and after swelling. Accurately weigh the freeze-dried hydrogel sample to be tested, then immerse it in PBS solution, incubate it in a 37°C water bath at 100r / min, take out the sample regularly (0.5, 1, 2, 3, 5, 7, 8, 10, 12h), wipe off the surface water with filter paper, and then accurately weigh the mass until the gel mass reaches equilibrium. Use formula (b) to calculate the swelling rate of the hydrogel:

[0119] (b)

[0120] The viscosity of the hydrogel at different temperature gradients (25, 30, 35, 36, 37°C) was measured using an NDJ-1 rotational viscometer. A suitable rotor was selected and inserted into the hydrogel and measured at an appropriate rotation speed. The readings were then recorded.

[0121] The degradation of freeze-dried chitosan / sodium β-glycerophosphate hydrogels was evaluated in PBS solution at 37°C, both with and without lysozyme. The freeze-dried hydrogels were incubated in PBS containing 0.2 mg lysozyme, and the PBS solution was refreshed every three days. The weight of the dried gel was measured at intervals of 1, 3, 5, 7, 10, 15, and 22 days. The degradation rate of the hydrogel was calculated using formula (c).

[0122] (c)

[0123] The porosity of hydrogels can be measured by gravimetric analysis, density measurement, and BET gas adsorption. In this experiment, the porosity of freeze-dried drug-loaded hydrogels and freeze-dried bare hydrogels was determined gravimetrically. The procedure was as follows: The hydrogel sample was immersed in anhydrous ethanol for 2 hours, then removed and the surface ethanol was carefully blotted with filter paper. The weight of the sample was then recorded. The porosity of the hydrogel was calculated using formula (d).

[0124] (d)

[0125] (8) In vitro release test

[0126] The release of ethinyl estradiol from drug-loaded hydrogels in PBS (pH = 7.4) buffer solution was studied. Hydrogels with different drug loadings (5 mg, 10 mg, 20 mg, 40 mg, 60 mg, 80 mg, 100 mg) and aqueous solutions of ethinyl estradiol were placed in dialysis bags. The bags were then immersed in a sealed container containing 100 mL of release medium, maintained at 37 °C and gently stirred at 100 rpm. At designated time intervals (0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, and 240 h), 4 mL of the release medium was removed for analysis, and an equal volume of fresh PBS buffer was added to keep the volume constant. Since the absorption wavelength of ethinyl estradiol is 281 nm, this wavelength was selected for detection to minimize the interference of cyclodextrin UV absorption. The release of EE was quantified by measuring the absorbance at 281 nm using a UV–vis spectrophotometer. Each experiment was repeated in triplicate, and the average data of each experiment were plotted.

[0127] (II) Experimental results

[0128] (1) Synthesis and characterization of chitosan / sodium β-glycerophosphate thermosensitive hydrogel loaded with ethinyl estradiol

[0129] IR analysis provided key insights into the structural modifications and interactions within the synthesized hydrogels and their components. The IR spectra of β-cyclodextrin, carboxymethyl-β-cyclodextrin, ethinyl estradiol, and carboxymethyl-β-cyclodextrin / ethinyl estradiol complex (Figure 2(A)) revealed significant changes, confirming the successful carboxymethylation of β-cyclodextrin and the inclusion of ethinyl estradiol within the carboxymethyl-β-cyclodextrin cavity. Further structural confirmation was obtained from the IR spectra of sodium β-glycerophosphate, chitosan, chitosan / sodium β-glycerophosphate hydrogel, and drug-loaded hydrogel (Figure 2(B)). XRD analysis of sodium β-glycerophosphate and the prepared chitosan / sodium β-glycerophosphate hydrogel was performed, as shown in Figure 2(C). The XRD spectrum of sodium β-glycerophosphate showed obvious crystalline peaks at 11.12°, 13.33°, 22.39°, 33.93°, and 46.48°, while the XRD spectrum of the hydrogel had almost no obvious crystalline peaks, indicating its amorphous nature. The UV-visible spectra of the insoluble drug ethinyl estradiol and the inclusion complex are shown in Figure 2(D) and Figure 2(E). As can be seen from the figure, the inclusion complex has a characteristic absorption peak at about 281nm. This indicates that ethinyl estradiol is able to form an inclusion complex with carboxymethyl-β-cyclodextrin, which may indicate that ethinyl estradiol enters the hydrophobic cavity of the cyclodextrin derivative through van der Waals interactions, hydrogen bonding interactions, electrostatic interactions, and hydrophobic effects. Calibration curve of Figure 2(F).

[0130] (2) Study on the sol-gel transition behavior and injectability of hydrogels

[0131] Figure 3(A) (a)-(c) shows photos of chitosan / sodium β-glycerophosphate hydrogel in sol (4°C) and gel (37°C) states, demonstrating the thermal sensitivity of the hydrogel. Figures 3A (d)-(j) and Figure 3(D) show the process of the hydrogel changing from sol to gel at 37°C, and it was found that the gelation time was less than 5 minutes. Figure 3(B) shows the changes in the viscosity of the temperature-sensitive hydrogel tested at different temperatures (25, 30, 34, 35, 36, 37°C). The gel was injectable under all test conditions. The study found that compared with the viscosity before injection (25°C), the viscosity of the gel in each group increased, reaching the maximum viscosity at 37°C. As the temperature continued to rise, the degree of gelation increased, and when the temperature required for sol-gel transformation was reached, the maximum viscosity was reached at 37°C. The injectability of the hydrogel is shown in Figure 2(C). When injected through a sterile syringe (0.5×20 mm RWLB), the hydrogel took on a droplet shape (Figure 2(D)), indicating that it can be used for injectable drug delivery, and this injectability makes it possible to fabricate hydrogels of various shapes and deliver them in a minimally invasive manner.

[0132] (3) Analysis of hydrogel swelling characteristics and porosity

[0133] The swelling rates of the blank hydrogel and the prepared drug-loaded hydrogel at room temperature and body temperature are shown in Figure 4 (A) and Figure 4 (B). Both hydrogels were shown to absorb water and swell rapidly. The swelling rate of the drug-loaded hydrogel was lower than that of the corresponding blank hydrogel because a large number of ethinyl estradiol drug particles were attached to the cross-linked hydrogel skeleton or the pores of the internal network structure, resulting in a decrease in the swelling degree of the drug-loaded hydrogel due to physical interaction. Over time, the swelling rate of the hydrogel increased to 487% without excessive swelling. Therefore, it does not lead to a decrease in the mechanical strength of the hydrogel, affect the growth of surrounding tissues, or cause abnormal biological indexes, thereby limiting its application. However, over time, the hydrogel degraded to a certain extent in the PBS solution, showing a certain downward trend. As shown in Figure 4 (C), the porosity of the blank hydrogel (at 37°C) was 57.4%, and the porosity of the drug-loaded hydrogel decreased to 29.1%. It can be seen that with the addition of drugs, the porosity also seems to decrease more significantly. Ethinyl estradiol particles are granular solids with a certain hydrophobicity. As the dosage of ethinyl estradiol increases, a large number of ethinyl estradiol particles are attached to the pore space in the cross-linked hydrogel skeleton or the internal network structure to occupy a certain physical space.

[0134] (4) In vitro degradation

[0135] Figure 5(A) shows the degradation curves of the samples. It can be seen that both groups of hydrogels showed significant weight loss within 1 day, and the degradation rate reached more than 50%, and showed an upward trend. The degradation rate of the hydrogel in PBS containing lysozyme was higher than that of pure PBS, because chitosan degraded slowly in aqueous solution, however, the degradation was accelerated in the presence of lysozyme. Starting from 3d, the weight loss rate of the two groups gradually stabilized, and the degradation rate was about 60%. This is because the cross-linked chitosan chains and sodium β-glycerophosphate were physically bonded to chitosan, maintaining the structure of the hydrogel. Chitosan is almost insoluble in a near-neutral environment, so the degradation rate of the hydrogel slowed down. After 30 days of hydrolysis in PBS, the degradation rate can reach more than 80%.

[0136] (5) Cytotoxicity analysis

[0137] The biocompatibility of the hydrogels was evaluated by cytotoxicity test using MTT assay. Figure 5(B) shows the effect of 5 different concentrations of hydrogel extracts on L929 cell viability after 24 and 48 h of incubation, with cell viability exceeding 85%. According to GB / T 16886.5-2003 (ISO 10993-5:1999), samples with cell viability above 75% are considered non-cytotoxic. This clearly indicates that the produced hydrogels have no adverse effects on human health. In conclusion, the developed hydrogels have demonstrated their suitability as in vivo delivery systems for active substances.

[0138] (6) In vitro release characteristics

[0139] The release efficiency of ethinyl estradiol in hydrogel systems with different drug loads was tested in buffer solution to evaluate the effect of hydrogel on the sustained release of ethinyl estradiol. As shown in Figure 6(A)-(G), the release rate gradually accelerated in the first 24 h of release. This can be attributed to the swelling process of the hydrogel, which led to an increase in internal pores, thereby accelerating the release of ethinyl estradiol. Continuous removal of 5 mL of solution to replenish PBS solution resulted in a continuous decrease in the content of ethinyl estradiol in the system, resulting in a continuous decrease in the release rate of ethinyl estradiol after 24 hours. At the same time, with the increase in the amount of drug added (5 mg-100 mg), the cumulative release efficiency of ethinyl estradiol gradually decreased. This indicates that higher drug doses can effectively prolong the duration of drug release, thereby facilitating sustained release.

[0140] Example 2

[0141] (1) Comparison between the CM-β-CD / EE inclusion complex loaded with thermosensitive hydrogel and the CM-β-CD / EE inclusion complex not loaded with thermosensitive hydrogel

[0142] Although the (CM-β-CD / EE inclusion complex) without thermosensitive hydrogel has improved the water solubility of ethinyl estradiol (EE) by using CM-β-CD (carboxymethyl-β-cyclodextrin), this method lacks an effective sustained-release medium and therefore cannot achieve long-term release of the drug in vivo. In contrast, the present application combines the thermosensitive phase transition, fixation and sustained-release technology of thermosensitive hydrogel to successfully disperse the hydrophobic EE evenly in the hydrophilic gel. This technology utilizes the property of thermosensitive hydrogel to undergo phase transition at human body temperature, allowing the EE inclusion complex to exist stably in the hydrogel and achieve sustained and controlled release through the hydrogel system.

[0143] Specifically, the thermosensitive hydrogel exhibits a phase transition under temperature changes in the body, thereby promoting the slow release of the drug. Unlike the CM-β-CD / EE inclusion complex, this method enables the sustained release of EE in the body through the sustained release effect of the gel, significantly prolongs the drug's duration of action, and provides a more long-lasting release capability. Therefore, compared with the method without thermosensitive hydrogel (CM-β-CD / EE inclusion complex), the thermosensitive hydrogel drug delivery system of the present application not only improves the stability of EE, but also significantly enhances the controlled release ability of the drug, overcoming the long-term release effect that cannot be achieved by simple inclusion complexes.

[0144] (a) Effect of CM-β-CD on improving the water solubility of EE and its effect on the dispersion of thermosensitive hydrogels

[0145] Figure 7 In the figure, the left bottle is a CM-β-CD / EE aqueous solution, and the right bottle is an EE aqueous solution. It can be clearly observed that CM-β-CD significantly improves the solubility of EE in water. This effect of improving water solubility provides the necessary basis for uniformly dispersing the hydrophobic drug EE into the hydrophilic thermosensitive hydrogel. Through the inclusion complexation of CM-β-CD, EE can be better dissolved and evenly distributed, which enables the subsequent thermosensitive hydrogel drug delivery system to achieve more stable drug release and improve its long-lasting effect in the body.

[0146] (b) CM-β-CD can significantly improve the dispersion of EE in gel

[0147] Figure 8 The dispersion of CM-β-CD / EE and EE in hydrogels is shown. It can be observed that due to the hydrophobicity of ethinyl estradiol (EE) itself, its dispersibility in hydrogel is poor, resulting in inability to distribute evenly. However, after inclusion with CM-β-CD, the water solubility of EE is significantly improved, thereby achieving uniform dispersion of EE in hydrogel. This improvement provides a basis for subsequent thermosensitive hydrogel drug delivery systems, allowing EE to be stably dispersed in the gel, thereby achieving a more sustained sustained release effect.

[0148] (c) Comparative data of sustained release capacity of (CM-β-CD / EE inclusion complex) loaded with thermosensitive hydrogel and (CM-β-CD / EE inclusion complex) without thermosensitive hydrogel

[0149] By comparing these two sustained-release curves (Figure 9 (A)-(B)), it can be clearly seen that after adding the thermosensitive hydrogel, the release rate of EE is significantly slower than that of the simple CM-β-CD / EE inclusion complex. The thermosensitive hydrogel, as a carrier, can evenly carry the ethinyl estradiol inclusion complex and prolong the release time of the drug through the sustained-release mechanism of the hydrogel. This effect enables the hydrophobic ethinyl estradiol drug to achieve long-term sustained release in vivo. Compared with the (CM-β-CD / EE inclusion complex) system without thermosensitive hydrogel, the method proposed in this application significantly improves the controlled release performance of the drug and provides a more stable and sustained drug release capability.

[0150] (2) Improvement of the preparation method of chitosan / sodium β-glycerophosphate thermosensitive hydrogel

[0151] (a) Innovation of preparation method and simplicity of operation:

[0152] The preparation method of chitosan / sodium β-glycerophosphate thermosensitive hydrogel in the patent document "CN109810263A-A preparation method and application of chitosan thermosensitive gel" takes 2-5 days, including multiple tedious steps of reaction and low-temperature standing. In contrast, the method of the present application only takes 10-20 minutes to complete the pre-treatment through simple dissolution and short-time cooling, and the operating conditions are mild, with low requirements for equipment and environment. This simplified preparation process not only significantly shortens the time, but also reduces the complexity of operation and production costs, and has obvious advantages in industrial application.

[0153] (b) Technical improvements in gelation time and controlled release performance:

[0154] Although the hydrogel in CN109810263A can complete gelation within 1-5 minutes, it fails to provide a stable drug release system. However, the present application achieves rapid gelation (≤2 minutes) by optimizing the ratio of chitosan to sodium β-glycerophosphate (such as 2% chitosan to 100% sodium β-glycerophosphate), while greatly prolonging the drug sustained release time and significantly reducing the risk of drug burst release. This technology not only overcomes the shortcomings of CN109810263A, but also provides a new solution for the application of thermosensitive hydrogels in the field of drug release.

[0155] (c) Technical data comparison and support:

[0156] Table 1 compares the preparation conditions and gel properties of this application and CN109810263A:

[0157] Table 1 Comparison of preparation conditions and gel properties between this application and CN109810263A

[0158]

[0159] The experimental results show that the method of this application has the comprehensive advantages of simple operation, rapid gelation, and long-term sustained release. In particular, in terms of drug release performance, this application achieves a controlled release effect that cannot be achieved by existing technologies. This difference is a breakthrough in the essence of the technology.

[0160] (3) Chitosan / sodium β-glycerophosphate thermosensitive sustained-release hydrogel drug delivery

[0161] (a) Technological innovation of hydrogels carrying water-soluble and hydrophobic drugs:

[0162] Compared with the chitosan / sodium β-glycerophosphate thermosensitive sustained-release hydrogel in the patent document "CN116350573A-Thermosensitive sustained-release drug-loaded gel preparation with bactericidal function and its preparation method", which only studies water-soluble drugs, this application proposes an effective technical solution for uniformly dispersing hydrophobic drugs into thermosensitive hydrogels for sustained release. The thermosensitive hydrogel in CN116350573A is only used for water-soluble drugs such as benzalkonium bromide (easily soluble in water), and fails to solve the problem of uniform dispersion of hydrophobic drugs. In contrast, this application uses cyclodextrin to encapsulate hydrophobic drugs (such as ethinyl estradiol), which effectively improves the solubility of hydrophobic drugs, so that they can be evenly dispersed in thermosensitive hydrogels. This method can not only carry water-soluble drugs, but also enable hydrophobic drugs to achieve sustained and controllable release in the body, significantly expanding the scope of application of thermosensitive hydrogels in the field of drug release.

[0163] (b) Comparison of drug dispersibility and hydrogel stability:

[0164] like Fig.10 As shown, the left figure is a thermosensitive hydrogel carrying ethinyl estradiol inclusion compound, and the right figure is a situation where ethinyl estradiol is directly added to the hydrogel. It can be clearly seen that the inclusion compound is combined with the thermosensitive hydrogel, not only can the uniform dispersion of the hydrophobic drug be achieved, but also the stability of the hydrogel can be maintained. If the hydrophobic drug is directly added to the hydrogel, there will be problems of uneven dispersion and decreased stability of the hydrogel. Therefore, the inclusion compound drug loading method provided by the application ensures the stability of the hydrogel system, and can effectively improve the uniform distribution of the drug, thereby improving its sustained release effect.

[0165] The description of the above embodiments is only used to understand the method and core idea of ​​the present invention. It should be pointed out that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications will also fall within the scope of protection of the claims of the present invention.

Claims

1. A controlled release pharmaceutical composition, characterized in that: The controlled-release pharmaceutical composition comprises a steroid drug, a cyclodextrin solubilizer, and a controlled-release carrier; Preferably, the controlled release carrier comprises a thermosensitive hydrogel; Preferably, the steroid drug can form an inclusion complex with the cyclodextrin solubilizing agent.

2. The controlled release pharmaceutical composition according to claim 1, characterized in that The steroid drugs include glucocorticoids, mineralocorticoids, and sex hormones; Preferably, the steroid drug is selected from sex hormones; Preferably, the sex hormones include ethinyl estradiol, estradiol, progesterone, medroxyprogesterone, methyltestosterone, testosterone undecanoate, and testosterone propionate; Preferably, the sex hormone is selected from ethinyl estradiol.

3. The controlled release pharmaceutical composition according to claim 1, characterized in that: The thermosensitive hydrogel includes chitosan thermosensitive hydrogel, Pluronic F127 hydrogel, PDLLA-PEG-PDLLA hydrogel, PLGA-PEG-PLGA hydrogel, and Mebiol® Gel hydrogel; Preferably, the thermosensitive hydrogel is selected from chitosan thermosensitive hydrogel; Preferably, the chitosan thermosensitive hydrogel comprises chitosan and sodium β-glycerophosphate; Preferably, the sodium β-glycerophosphate is pentahydrate.

4. The controlled release pharmaceutical composition according to claim 1, characterized in that: The cyclodextrin solubilizing agent includes cyclodextrin or its derivatives; Preferably, the cyclodextrin includes α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin; Preferably, the cyclodextrin solubilizing agent is a β-cyclodextrin derivative; Preferably, the β-cyclodextrin derivative is carboxymethyl-β-cyclodextrin.

5. The controlled release pharmaceutical composition according to claim 1, characterized in that: The controlled-release pharmaceutical composition comprises chitosan thermosensitive hydrogel and ethinylestradiol / carboxymethyl-β-cyclodextrin inclusion compound; Preferably, the controlled release pharmaceutical composition further comprises pharmaceutically acceptable excipients other than the solubilizer.

6. The controlled release pharmaceutical composition according to claim 1, characterized in that: The controlled-release pharmaceutical composition is administered in a suitable dosage form; Preferably, the dosage form includes a dosage form for enteral administration and a dosage form for parenteral administration; Preferably, the non-gastrointestinal administration dosage form includes an injection dosage form, a respiratory tract administration dosage form, a cavity administration dosage form, a mucosal administration dosage form, and a skin administration dosage form; Preferably, the parenteral dosage form is selected from an injection dosage form; Preferably, the injectable dosage form includes intravenous injection, intramuscular injection, subcutaneous injection, intradermal injection or intracavity injection.

7. A method for preparing the controlled release pharmaceutical composition according to any one of claims 1 to 6, characterized in that: The method comprises mixing a controlled release carrier with a drug / cyclodextrin solubilizer inclusion complex.

8. The method according to claim 7, characterized in that The method comprises mixing a chitosan thermosensitive hydrogel with an ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound; Preferably, the method comprises immersing the chitosan thermosensitive hydrogel in the inclusion complex supernatant to obtain the drug-loaded hydrogel; Preferably, the chitosan thermosensitive hydrogel is in a freeze-dried state; Preferably, the method further comprises a method for preparing an ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex, wherein the steps of the preparation method comprise mixing ethinyl estradiol with carboxymethyl-β-cyclodextrin; Preferably, the preparation method of the ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion complex includes a saturated aqueous solution method, an embedding method, a microwave method, a co-grinding method, an ultrasonic method, and a suspension method; Preferably, the preparation method is selected from the saturated aqueous solution method; Preferably, the saturated aqueous solution method comprises mixing an aqueous solution of carboxymethyl-β-cyclodextrin with an organic solution of ethinyl estradiol; Preferably, the carboxymethyl-β-cyclodextrin aqueous solution is a saturated aqueous solution; Preferably, the molar usage of ethinyl estradiol and carboxymethyl-β-cyclodextrin is 1:1 to 100:1; Preferably, the molar usage of ethinyl estradiol and carboxymethyl-β-cyclodextrin is 1:1; Preferably, the ethinyl estradiol organic solution includes ethinyl estradiol methanol solution, ethinyl estradiol ethanol solution, ethinyl estradiol isopropanol solution; Preferably, the ethinyl estradiol organic solution is selected from ethinyl estradiol ethanol solution; Preferably, the volume ratio of the aqueous solution to the organic solution is 5:1 to 20:1; Preferably, the volume ratio of the aqueous solution to the organic solution is 10:1; Preferably, the method further comprises a method for preparing chitosan / sodium β-glycerophosphate hydrogel, wherein the steps of the preparation method comprise mixing a chitosan solution with a sodium β-glycerophosphate solution; Preferably, the chitosan solution is used at a concentration of 1% (w / v) to 5% (w / v); Preferably, the chitosan solution is used at a concentration of 2% (w / v); Preferably, the use concentration of the sodium β-glycerophosphate solution is 50% (w / v) to 200% (w / v); Preferably, the use concentration of the sodium β-glycerophosphate solution is 100% (w / v); Preferably, the volume ratio of the chitosan solution to the sodium β-glycerophosphate solution is 10:1 to 1:1; Preferably, the volume ratio of the chitosan solution to the sodium β-glycerophosphate solution is 1:1; Preferably, the chitosan is dissolved using hydrochloric acid; Preferably, the sodium β-glycerophosphate is dissolved in distilled water; Preferably, the method further comprises a method for preparing carboxymethyl-β-cyclodextrin, wherein the method comprises synthesizing carboxymethyl-β-cyclodextrin using β-cyclodextrin and chloroacetic acid under alkaline conditions.

9. The method according to claim 8, characterized in that The method comprises mixing a chitosan solution with a concentration of 2% (w / v) and a 100% (w / v) sodium β-glycerophosphate solution at a volume ratio of 1:1 to obtain a chitosan / sodium β-glycerophosphate hydrogel, mixing a saturated aqueous solution of carboxymethyl-β-cyclodextrin and an ethinyl estradiol ethanol solution at a volume ratio of 10:1 to obtain an ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound, wherein the solute usage amounts of ethinyl estradiol and carboxymethyl-β-cyclodextrin are equimolar, and mixing the chitosan / sodium β-glycerophosphate hydrogel and the ethinyl estradiol / carboxymethyl-β-cyclodextrin inclusion compound.

10. Any of the following applications: (1) Use of the controlled release pharmaceutical composition according to any one of claims 1 to 6 in the preparation of a controlled release injection; (2) Use of the controlled-release pharmaceutical composition according to any one of claims 1 to 6 in the preparation of estrogen supplementary drugs; (3) Use of the controlled-release pharmaceutical composition according to any one of claims 1 to 6 in the preparation of contraceptive drugs; (4) Use of the controlled-release pharmaceutical composition according to any one of claims 1 to 6 in improving the bioavailability of a drug; (5) Use of the controlled-release pharmaceutical composition according to any one of claims 1 to 6 in increasing the drug loading of ethinyl estradiol; (6) Use of the controlled-release pharmaceutical composition according to any one of claims 1 to 6 for improving the solubility of hydrophobic drugs.

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