Octreotide acetate sustained-release microsphere, preparation method therefor, and use thereof

Abstract

An octreotide acetate sustained-release microsphere, a preparation method therefor, and a use thereof. The preparation method comprises the following steps: S1, dissolving a polylactic acid-glycolic acid copolymer in a first organic solvent to prepare an oil phase 1, and dissolving octreotide acetate in a second organic solvent to prepare an oil phase 2; S2, adding the oil phase 2 into the oil phase 1 while stirring to obtain a suspension containing octreotide acetate; S3, transferring the suspension into a water phase for emulsification to obtain a semi-cured drug-loaded microsphere; and S4, transferring the semi-cured drug-loaded microsphere into a curing phase, and removing the solvent to obtain an octreotide acetate sustained-release microsphere. The octreotide acetate sustained-release microsphere having high drug loading efficiency and high encapsulation efficiency is prepared; and upon experimental tests, the encapsulation efficiency can reach 90% or above, the drug stability is good, and the bioavailability is high, so that the octreotide acetate shows higher application value and a more remarkable use effect.

Description

Octreotide acetate sustained-release microspheres, preparation method, and application thereof Technical Field

[0001] The present invention relates to the technical field of microsphere pharmaceutical preparations, and in particular to octreotide acetate sustained-release microspheres, a preparation method thereof, and an application thereof. Background Art

[0002] Octreotide is a synthetic octapeptide derivative of natural somatostatin, first synthesized in 1979. It retains the same pharmacological effects as growth hormone and can inhibit the secretion of many hormones, including secretin, cholecystokinin, glucagon, growth hormone (GH), insulin, pancreatic polypeptide, thyrotropin, and vasoactive intestinal peptide. It is primarily used clinically to treat acromegaly and gastrointestinal and pancreatic endocrine tumors, and has a wide range of clinical applications.

[0003] There are two FDA-approved octreotide acetate formulations: an injectable solution for subcutaneous administration three times daily and a reservoir-type injectable microsphere for intramuscular administration once a month, with a maximum dosing cycle of one month. The one-month formulation addresses some of the compliance issues associated with the daily injection. However, these one-month sustained-release octreotide acetate microspheres require a special glucose-PLGA star polymer (GLU-PLGA) matrix.

[0004] Researchers at home and abroad often use the polymer material PLGA as a carrier and the double emulsion method (W / O / W method) to prepare octreotide acetate sustained-release microspheres. However, the development of octreotide sustained-release microspheres faces a series of problems, among which uneven microsphere size, low encapsulation efficiency, and severe burst release are the main issues. Their application also has some shortcomings: the microsphere size generally ranges from 1 to 500 μm, ranging from a few nanometers to 800 μm. The required injection needle is relatively thick, which can cause pain, induration, or redness at the injection site. The uneven microsphere size can affect drug release. Poor material degradation can easily cause inflammation.

[0005] Patents disclose some methods to improve the roundness and encapsulation efficiency of microspheres, but the results are minimal. Chinese patent CN102940609A discloses a high-encapsulation-efficiency octreotide sustained-release microsphere and a preparation method thereof. The prepared microspheres have an encapsulation efficiency of 46%, a large range of microsphere particle sizes, and are uneven. In addition, a large amount of excipients are added during the microsphere preparation process, resulting in a complex process.

[0006] Chinese patent CN114948881A discloses octreotide acetate microspheres and a preparation method thereof. Octreotide microspheres are prepared by single emulsification, and the encapsulation efficiency of the prepared microspheres is low. In order to prepare microspheres with a high drug loading rate, a large amount of octreotide drug needs to be added, which increases the input amount and cost of the drug.

[0007] Summary of the Invention

[0008] In view of the deficiencies in the prior art, the first aspect of the present invention provides a method for preparing octreotide acetate sustained-release microspheres, the preparation method comprising the following steps:

[0009] S1. The polylactic acid - glycolic acid copolymer is dissolved in a first organic solvent to prepare an oil phase 1; octreotide acetate is dissolved in a second organic solvent to prepare an oil phase 2;

[0010] S2. Under stirring conditions, the oil phase 2 was added to the oil phase 1 to obtain a suspension containing octreotide acetate;

[0011] S3. Transferring the suspension to an aqueous phase and emulsifying to obtain semi-solidified drug-loaded microspheres;

[0012] S4. Transfer the semi-solidified drug-loaded microspheres to the solidified phase, remove the solvent, and obtain octreotide acetate sustained-release microspheres.

[0013] In some embodiments, the poly(lactic acid-glycolic acid) copolymer has a relative molecular mass of 12,000-36,000, a molar ratio of lactic acid to glycolic acid of (50-75): (25-50), and an intrinsic viscosity of 0.15-0.45 dL / g.

[0014] Furthermore, the relative molecular mass of the polylactic acid-glycolic acid copolymer is 24,000-36,000, the molar ratio of lactic acid to glycolic acid is 50:50, and the intrinsic viscosity is 0.3-0.4 dL / g. The preferred source is Shenzhen Lvbao Technology Co., Ltd.

[0015] The applicant discovered in experiments that the parameters of polylactic acid-glycolic acid copolymer, especially viscosity, have a significant impact on the morphology and particle size of the microspheres. Excessively high or low viscosity not only causes the microspheres to be non-round, but may also cause uneven particle size. Only when its intrinsic viscosity is 0.3-0.4 dL / g can the morphology and particle size be better, the stability be optimal, and the encapsulation efficiency be highest.

[0016] In some embodiments, the first organic solvent comprises at least one of ethyl acetate, ethyl formate, methyl formate, methyl acetate, butanone, tetrahydrofuran, acetone, acetonitrile, dimethyl sulfoxide, dichloromethane, chloroform, trichloroethylene, ethylene glycol ether, and triethanolamine.

[0017] In some embodiments, the second organic solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0018] In some embodiments, the aqueous phase and the solid phase are both buffer solutions containing surfactants and metal salts.

[0019] Furthermore, the buffer solution includes at least one of acetate buffer, phosphate buffer, and citrate buffer.

[0020] Furthermore, the pH of the buffer solution is 3.0-5.5, and further, the pH of the buffer solution is 4.5.

[0021] The pH value of the buffer solution has a significant effect on the encapsulation efficiency of the microspheres. Too high or too low a pH value will reduce the encapsulation efficiency. The encapsulation efficiency is highest only when the pH is 4.5. The reason may be that the drug stability of octreotide acetate is the highest at this pH.

[0022] In some embodiments, the mass percentage of the polylactic acid-glycolic acid copolymer in the oil phase 1 is 30%-60%.

[0023] In some embodiments, the surfactant includes at least one of Tween, Span, PVA, poloxamer, and betaine.

[0024] Furthermore, the mass volume percentage concentration of the surfactant is 1%-10%, preferably, the mass volume percentage concentration of the surfactant is 3%.

[0025] Furthermore, the metal salt includes but is not limited to common types in the art, such as at least one of sodium chloride or potassium chloride. The mass volume percentage concentration of the metal salt is 5%-20%, preferably, the mass volume percentage concentration of the metal salt is 10%.

[0026] Furthermore, the S4 further includes centrifuging or filtering the octreotide acetate sustained-release microspheres to remove excess solvent and surfactant, washing with deionized water, repeating centrifugation and washing for more than 5 times, freeze-drying the microspheres using a freeze dryer, and finally obtaining octreotide acetate sustained-release microsphere freeze-dried powder.

[0027] The second aspect of the present invention provides octreotide acetate sustained-release microspheres, wherein the encapsulation efficiency of the sustained-release microspheres is greater than 90%.

[0028] The third aspect of the present invention provides a use of octreotide acetate sustained-release microspheres in preparing medicines.

[0029] The fourth aspect of the present invention provides a medicine, the preparation raw materials of which include octreotide acetate sustained-release microspheres and pharmaceutically acceptable excipients.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention prepares octreotide acetate sustained-release microspheres with high drug loading rate and high encapsulation rate. Experimental tests show that the encapsulation rate can reach more than 90%, the drug has good stability, and the bioavailability is high, which makes octreotide acetate show greater application value and more significant use effect.

[0032] 2. The microspheres prepared by the present invention have a stable in vitro sustained release, and the cumulative dissolution rate test shows that they extend the release period of water-soluble drugs.

[0033] 3. The present invention has explored the optimal buffer pH value in this system. The microspheres prepared at a pH of 4.5 are round and smooth in appearance and have a high encapsulation efficiency.

[0034] 4. The present invention explores the most suitable viscosity of the polylactic acid-glycolic acid copolymer in this system. When the intrinsic viscosity is 0.3-0.4 dL / g, the microspheres prepared have the best morphology, the best stability and the highest encapsulation efficiency.

[0035] 5. The microspheres prepared by the present invention have uniform and narrow particle size distribution, the raw materials for preparation are simple and easy to obtain, the preparation process is easy to scale up, and there is a broad prospect for industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a diagram showing the surface morphology of the sustained-release microspheres of Example 1 of the present invention.

[0037] FIG2 is a surface morphology diagram of the sustained-release microspheres of Comparative Example 2 of the present invention.

[0038] FIG3 is a comparison chart of the cumulative dissolution rates of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0039] Example 1

[0040] A method for preparing octreotide acetate sustained-release microspheres, comprising the following steps:

[0041] S1. Dissolve 2.3g of polylactic acid-glycolic acid copolymer in 5.5g of a first organic solvent, ethyl acetate, to prepare oil phase 1; dissolve 0.2g of octreotide acetate in 0.8g of a second organic solvent, dimethyl sulfoxide, to prepare oil phase 2; the polylactic acid-glycolic acid copolymer has a relative molecular mass of 24,000-36,000, a molar ratio of lactic acid to glycolic acid of 50:50, and an intrinsic viscosity of 0.3-0.4dL / g, and its source is the same as the preferred source in the content of the invention.

[0042] S2. Under stirring conditions, the stirring speed was set to 500 rpm, and oil phase 2 was added to oil phase 1 (mass ratio of oil phase 1:oil phase 2 = 7:1). The resulting initial suspension was stirred at 5000 rpm for 5 minutes to obtain a suspension containing octreotide acetate;

[0043] S3. The suspension in S2 was transferred to 50 mL of aqueous phase and emulsified to obtain semi-solidified drug-loaded microspheres; the aqueous phase was an acetate buffer solution (pH 4.5) containing 3 wt % of the surfactant poloxamer and 10 wt % of sodium chloride;

[0044] S4. The semi-solidified drug-loaded microsphere solution in S3 was transferred to 100 mL of a solid phase, the temperature was raised to 40°C, and the vacuum was maintained at 400 mbarr for 120 minutes; the temperature was maintained at 40°C, and the vacuum was increased to 150 mbarr for 90 minutes to remove the solvent to obtain octreotide acetate sustained-release microspheres; the solid phase was an acetate buffer solution (pH 4.5) containing 16 wt% of the surfactant poloxamer and 10 wt% of the metal salt sodium chloride; the octreotide acetate sustained-release microspheres were washed with deionized water, repeatedly centrifuged and washed 5 times, and the microspheres were freeze-dried in a freeze dryer to finally obtain a lyophilized powder of sustained-release microspheres.

[0045] Example 2

[0046] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation manner is the same as that of Example 1, except that the amount of polylactic acid-glycolic acid copolymer is 1.65 g.

[0047] Example 3

[0048] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation manner is the same as that of Example 1, except that the amount of polylactic acid-glycolic acid copolymer is 3.3 g.

[0049] Example 4

[0050] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation method is the same as that of Example 2, except that the pH value of the acetate buffer solution is 3.0.

[0051] Example 5

[0052] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation method is the same as that of Example 2, except that the pH value of the acetate buffer solution is 5.5.

[0053] Example 6

[0054] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation method is the same as that of Example 1, except that the aqueous phase is an acetate buffer solution (pH 4.5) containing 1wt% of a surfactant poloxamer and 15wt% of sodium chloride; and the solid phase is an acetate buffer solution (pH 4.5) containing 10wt% of a surfactant poloxamer and 20wt% of a metal salt sodium chloride.

[0055] Comparative Example 1

[0056] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation manner is the same as that of Example 1, except that the preparation method comprises the following steps:

[0057] S1. Weigh 3g of poly(lactic acid - glycolic acid) copolymer and dissolve it in 7g of ethyl acetate to prepare an oil phase; dissolve 0.25g of octreotide acetate in 1g of ultrapure water to prepare an aqueous phase;

[0058] S2. The stirring speed was set to 500 rpm, and the inner aqueous phase was slowly added dropwise to the oil phase (mass ratio of inner aqueous phase: oil phase = 7:1). The resulting initial suspension was stirred at 5000 rpm for 5 minutes to form a suspension containing drug particles;

[0059] S3. The suspension in S2 was transferred to 50 mL of an external aqueous phase containing 3 wt% poloxamer surfactant for emulsification and solidification. The temperature was raised to 40°C and the vacuum was maintained at 400 mbarr for 120 minutes; the temperature was maintained at 40°C and the vacuum was increased to 150 mbarr for 90 minutes to remove the solvent to obtain octreotide acetate sustained-release microspheres. The octreotide acetate sustained-release microspheres were washed with deionized water, centrifuged and washed repeatedly for 5 times, and the microspheres were freeze-dried using a freeze dryer to finally obtain lyophilized powder of sustained-release microspheres.

[0060] Comparative Example 2

[0061] A method for preparing octreotide acetate sustained-release microspheres, the specific implementation method is the same as that of Comparative Example 1, except that the external aqueous phase is an acetate buffer solution (pH 4.5) containing 3wt% of a surfactant, poloxamer, and 10wt% of sodium chloride.

[0062] Performance Testing

[0063] The octreotide acetate sustained-release microspheres prepared in the above examples and comparative examples were subjected to the following tests.

[0064] (1) Morphology detection: measured using a WD300-48LT biological microscope, see Figures 1-2;

[0065] (2) Particle size detection: 50 mg of octreotide acetate sustained-release microspheres were added to an aqueous solution of Tween 80 (Tween 80 content was 0.5 wt%). After the sample was evenly dispersed, its particle size was measured by a particle size laser spectrophotometer. The average of the measurements was taken after 3 measurements.

[0066] (3) Drug loading rate and dissolution rate detection: Determined by liquid chromatography, C18 column, wavelength 210nm.

[0067] Mobile phase A: Tetramethylammonium hydroxide solution (take 20 mL of 10% tetramethylammonium hydroxide solution, add 880 mL of water, and adjust the pH to 5.4 with 10% phosphoric acid solution) - acetonitrile (900:100) (V / V)

[0068] Mobile phase B: Tetramethylammonium hydroxide solution (take 20 mL of 10% tetramethylammonium hydroxide solution, add 380 mL of water, and adjust the pH to 5.4 with 10% phosphoric acid solution) - acetonitrile (400:600) (V / V)

[0069] Gradient elution:

[0070] Flow rate: 0.2 mL / min, column temperature: 30°C

[0071] Drug loading rate = (drug content in microspheres / total weight of microspheres) × 100%;

[0072] Encapsulation efficiency = (actual drug loading rate / theoretical drug loading rate) × 100%.

[0073] Cumulative dissolution rate (%) after each time point = 100% × (C1 + C2 + ... Cn) × V / L, where Cn is the drug concentration after removal at each time point, V is the fixed sampling volume at each time point (since the entire sample is removed and then replenished with the same volume of medium, the sampling volume is equivalent to the dissolution medium volume), and L is the total drug content. See Figure 3 for experimental results.

[0074] In Examples 1-3, experiments varying the poly(lactic-co-glycolic acid) (PLGA) concentration revealed that increasing the PLGA concentration resulted in larger microsphere particle sizes. This is because increasing the PLGA concentration increases the viscosity of the oil phase 1, and higher PLGA viscosity leads to larger microsphere particle sizes. At lower PLGA concentrations, the drug easily escapes into the aqueous phase, resulting in lower drug loading efficiency. When the PLGA concentration was 43%, the average microsphere particle size was 43 μm.

[0075] In Examples 2, 4, and 5, by changing the pH of the buffer solution in the aqueous phase and the solid phase, when the pH was 3.0 or 6.0, the drug loading rate and encapsulation efficiency of the prepared microspheres decreased. This may be because under strong acid or weak acid conditions, the stability of octreotide in the aqueous phase and the solid phase was poor, resulting in octreotide easily escaping, resulting in low drug loading rate and encapsulation efficiency of the finally prepared microspheres; when the pH in the aqueous phase and the external aqueous phase was 4.5, the drug loading rate and encapsulation efficiency of the prepared microspheres were the highest, with an encapsulation efficiency of 93%.

[0076] The drug loading rate and encapsulation efficiency of the microspheres prepared by the single emulsion method in the comparative example are low, which may be because octreotide is a hydrophilic drug and is extremely unstable. By using the double emulsification method, a certain proportion of surfactants and metal salts are added to the external aqueous phase and the solidification phase, thereby protecting the stability of octreotide during the emulsification and solidification processes, preventing octreotide from being affected by the water-oil interface and stirring shear force, and thus improving the drug loading rate and encapsulation efficiency of octreotide.

[0077] From the above analysis, it can be seen that the particle size of the microspheres prepared by the present invention is concentrated in the range of 30-60 μm, the drug loading rate can reach 7.59%, and the encapsulation efficiency can reach 93%. The drug microspheres are spherical, with good encapsulation effect, high repeatability, and stable in vitro sustained release of the drug. The present invention has the potential for further expansion.

Claims

1. A method for preparing octreotide acetate sustained-release microspheres, characterized in that: The preparation method comprises the following steps: S1. dissolving polylactic acid-co-glycolic acid in a first organic solvent to obtain an oil phase 1; dissolving octreotide acetate in a second organic solvent to obtain an oil phase 2; S2. Under stirring conditions, the oil phase 2 is added to the oil phase 1 to obtain a suspension containing octreotide acetate; S3. transferring the suspension into the aqueous phase and emulsifying to obtain semi-solidified drug-loaded microspheres; S4. Transfer the semi-solidified drug-loaded microspheres to the solid phase, remove the solvent, and obtain octreotide acetate sustained-release microspheres.

2. The method for preparing octreotide acetate sustained-release microspheres according to claim 1, characterized in that: The relative molecular weight of the polylactic acid-glycolic acid copolymer is 12000-36000, the molar ratio of lactic acid to glycolic acid is (50-75): (25-50), and the intrinsic viscosity is 0.15-0.45 dL / g.

3. The method for preparing octreotide acetate sustained-release microspheres according to claim 2, characterized in that: The first organic solvent includes at least one of ethyl acetate, ethyl formate, methyl formate, methyl acetate, butanone, tetrahydrofuran, acetone, acetonitrile, dimethyl sulfoxide, dichloromethane, chloroform, trichloroethylene, ethylene glycol ether, and triethanolamine.

4. The method for preparing octreotide acetate sustained-release microspheres according to claim 2, characterized in that: The second organic solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

5. The method for preparing octreotide acetate sustained-release microspheres according to claim 4, characterized in that: The aqueous phase and the solid phase are both buffer solutions containing surfactants and metal salts.

6. The method for preparing octreotide acetate sustained-release microspheres according to claim 5, characterized in that: The mass percentage of the polylactic acid-glycolic acid copolymer in the oil phase 1 is 30%-60%.

7. The method for preparing octreotide acetate sustained-release microspheres according to claim 5, characterized in that: The surfactant includes at least one of Tween, Span, PVA, poloxamer and betaine.

8. Octreotide acetate sustained-release microspheres obtained according to the preparation method according to any one of claims 1 to 7, characterized in that: The encapsulation rate of the sustained-release microspheres is greater than 90%.

9. Use of the octreotide acetate sustained-release microspheres according to claim 8 in preparing medicines.

10. A drug, characterized in that The preparation raw materials include the octreotide acetate sustained-release microspheres according to claim 8 and pharmaceutically acceptable excipients.

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