Depot composition with controlled initial release and method for producing the same

Abstract

The present invention relates to a depot composition containing a hydrophobic amino acid inside microspheres, which is a dosage form containing a biodegradable polymer and an active ingredient, and can prevent the active ingredient from being released in excessive amounts at the beginning. Since the composition has excellent suspension ability, the active ingredient can be uniformly and continuously effective even when used as an injection by general users.

Description

Technical Field

[0001] The present invention relates to a depot composition, specifically, it contains hydrophobic amino acids inside microspheres to control initial release, and provides high user convenience through excellent resuspension characteristics.

[0002] The present invention is related to the technical development of a patient-ordered drug release regulation (sustained injection technology) improved pharmaceutical product (project number: 20014981) for entering the Middle East and Association of Southeast Asian Nations (ASEAN) markets of the customized diagnosis and treatment business of bio-industry technology development, which was carried out with the support of the Korea Institute of Industrial Technology Evaluation and Management using the funds of the Ministry of Trade, Industry and Energy of the Republic of Korea.

Background Art

[0003] A depot preparation is one of the injectable dosage forms made to have a long-lasting drug effect, and it is a dosage form that can be mainly used when attempting to administer hormones for a long period of time. The depot preparation, which is a sustained-release dosage form, has the advantage of minimizing the number of injections for patients, but it is difficult to achieve a constant and continuous drug release during the entire release period after injection. In particular, when the initial release, in which the drug in the depot is released in excess at the initial stage of injection, is high, side effects may occur due to the excessive drug, and the sustained effect of the drug effect may decline during the specified period. Therefore, controlling the initial release in depot preparations is very important.

[0004] GLP-1 agonists such as liraglutide and semaglutide were initially developed to lower blood glucose in diabetic patients, but it was confirmed that such drugs are also effective in reducing the weight of obese patients, and they are drugs used for the treatment of diabetes and obesity. They are analogs of the incretin hormone secreted from the intestinal tract, which increase the amount of insulin secreted after a meal and extend the excretion time of the contents in the gastrointestinal tract so that food slowly moves from the stomach to the small intestine. In addition, it can act on the central nervous system to lower blood glucose and assist in weight loss through various actions that suppress appetite.

[0005] However, if the body is exposed to an excessive amount of liraglutide, side effects such as nausea, diarrhea, increased heart rate, hypoglycemia, or headache may occur. Therefore, controlling the initial release of liraglutide in depot formulations containing it as the active ingredient is one of the most important challenges.

[0006] On the other hand, Japanese Patent No. 5681626 discloses that a sustained-release formulation containing microspheres formed by the bonding of a sterol-containing lipid component and a polylactic acid-glycolic acid copolymer (PLGA) polymer, along with a phospholipid component, can control the release rate. However, in the case of lipids, it does not show sufficient effect in suppressing initial release and has the disadvantage of causing poor properties of the microspheres due to its strong hydrophobic characteristics. Furthermore, modifying the polylactic acid-glycolic acid copolymer (PLGA) polymer that forms the microspheres would cause difficulties in obtaining approval for drug use, thus limiting the practical application of the composition in depot formulations.

[0007] Furthermore, in the case of depot formulations, the microspheres can be stored in a lyophilized state to ensure drug storage safety and then suspended in sterile water for injection before injection. In this case, if the suspendability of the microspheres decreases, a smaller dose than the prescribed single dose may be administered, making it difficult to obtain sufficient drug effect. Also, low suspendability can lead to the formation of clumps and precipitates of microspheres, which may cause the injection needle to become blocked, making injection difficult. Therefore, the suspendability of the microspheres is a very important factor.

[0008] Thus, conventional sustained-release microspheres have limitations in providing depot agents with well-controlled initial release. Therefore, there is still a need for the development of depot compositions with appropriate resuspension properties and controlled initial release characteristics. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 5681626 [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention was devised to solve the aforementioned problems, and the object of the present invention is to provide a depot composition with excellent resuspendability and suppression of excessive initial drug release, and a method for producing the same.

[0011] The inventors of the present invention have strived to develop a depot composition that can control the excessive initial release of a drug. As a result, they have confirmed that by including a hydrophobic amino acid as a release control substance in the oil and aqueous phases of microspheres, the initial release of the drug can be suppressed. Furthermore, they have confirmed that microspheres containing the hydrophobic amino acid have uniform properties and excellent suspension ability, thus possessing excellent formulation characteristics as a depot agent, and have completed the present invention. [Means for solving the problem]

[0012] The present invention provides a depot composition comprising microspheres containing an oil phase (O layer) containing a biodegradable polymer and hydrophobic amino acids.

[0013] The aforementioned microspheres may further contain hydrophobic amino acids in the aqueous phase layer.

[0014] The microspheres may have a bulk density (BD) of 0.1 g / ml or more and a zeta potential of -8 mV to -30 mV.

[0015] The hydrophobic amino acid can be selected from the group consisting of valine, methionine, alanine, phenylalanine, tryptophan, isoleucine, and leucine.

[0016] The microspheres may also be microspheres produced by containing hydrophobic amino acids in an oil phase solution at a concentration of less than 1.5 parts by weight per 100 parts by weight of biodegradable polymer.

[0017] The microspheres may be microspheres produced by containing hydrophobic amino acids at a concentration of 0.05% (w / v) to 25% (w / v) relative to the total aqueous phase solution.

[0018] The biodegradable polymer may be a polymer containing lactide and glycolide as monomers.

[0019] The biodegradable polymer may have an inherent viscosity of 0.35 dL / g to 0.65 dL / g.

[0020] The present invention also provides a method for producing a depot composition, including the steps of preparing an oil phase (O) solution containing a hydrophobic amino acid and a biodegradable polymer, or mixing a first water phase (W1) solution containing a water-soluble solvent with the oil phase (O) solution to prepare a W1 / O emulsion; and adding the oil phase solution or the W1 / O emulsion to a second water phase (W2) solution to produce an O / W2 emulsion or a W1 / O / W2 emulsion.

[0021] The second water phase (W2) solution may further contain a hydrophobic amino acid.

[0022] The hydrophobic amino acid may be contained in the oil phase solution at less than 1.5 parts by weight based on 100 parts by weight of the biodegradable polymer.

[0023] The hydrophobic amino acid may be contained in the second water phase solution at 0.05% (w / v) to 25.0% (w / v) based on the whole of the second water phase solution.

[0024] The method may further include the step of drying and / or filtering the produced O / W2 emulsion or W1 / O / W2 emulsion and then centrifuging to recover microspheres.

Advantages of the Invention

[0025] The microspheres of the depot composition of the present application contain hydrophobic amino acids, and can control the excessive release of the active ingredient contained inside the microspheres at the initial stage of depot agent injection. Since they have excellent suspension ability, when the user administers them by injection, the effect of the active ingredient can be obtained uniformly and continuously.

Brief Description of Drawings

[0026] [Figure 1a] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using liraglutide as the API, showing microspheres that do not contain hydrophobic amino acids. [Figure 1b] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using liraglutide as the API, showing microspheres that contain hydrophobic amino acids in the first aqueous layer. [Figure 1c] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using liraglutide as the API, showing microspheres that contain hydrophobic amino acids in the second aqueous layer. [Figure 1d] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using liraglutide as the API, showing microspheres that contain hydrophobic amino acids in the oil layer. [Figure 1e] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using liraglutide as the API, showing microspheres that contain hydrophobic amino acids in the oil layer and the second aqueous layer. [Figure 1f] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using semaglutide as the API, showing microspheres that do not contain hydrophobic amino acids. [Figure 1g] SEM photograph of PLGA microspheres produced according to an embodiment of the present invention, in the case of using semaglutide as the API, showing microspheres that contain hydrophobic amino acids in the oil layer and the second aqueous layer. [Figure 2a]This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing valine. [Figure 2b] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing methionine. [Figure 2c] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing phenylalanine. [Figure 2d] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing tryptophan. [Figure 2e] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing leucine. [Figure 3a] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres that do not contain hydrophobic amino acids. [Figure 3b] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres that do not contain hydrophobic amino acids and are coated with leucine. [Figure 4a] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing cholesterol. [Figure 4b] This is an SEM image of PLGA microspheres produced according to one embodiment of the present invention, showing microspheres containing the cationic lipid DOTAP (Dioleoyl-3-trimethylammonium propane). [Figure 5a] This is an SEM image of PLGA microspheres containing leucine in an oil layer produced according to one embodiment of the present invention. [Figure 5b] This is an SEM image of PLGA microspheres containing leucine in an oil layer produced according to one embodiment of the present invention. [Figure 5c] This is an SEM image of PLGA microspheres containing leucine in an oil layer produced according to one embodiment of the present invention. [Figure 6a]This is an SEM image of PLGA microspheres containing leucine in the oil layer and second aqueous phase layer, manufactured according to one embodiment of the present invention. [Figure 6b] This is an SEM image of PLGA microspheres containing leucine in the oil layer and second aqueous phase layer, manufactured according to one embodiment of the present invention. [Figure 6c] This is an SEM image of PLGA microspheres containing leucine in the oil layer and second aqueous phase layer, manufactured according to one embodiment of the present invention. [Figure 6d] This is an SEM image of PLGA microspheres containing leucine in the oil layer and second aqueous phase layer, manufactured according to one embodiment of the present invention. [Figure 7] This graph shows the DSC analysis results of microspheres produced according to one embodiment of the present invention. [Figure 8] This graph shows the long-term release characteristics of microspheres produced according to one embodiment of the present invention. [Figure 9] This graph shows the results of confirming the drug release behavior in vivo of microspheres produced according to one embodiment of the present invention. [Modes for carrying out the invention]

[0027] The present invention will be described in detail below.

[0028] However, the present invention can be modified in various ways and may take many forms. The specific examples and descriptions below are provided only to aid in understanding the present invention and do not limit the invention to any particular form of disclosure. The scope of the present invention should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0029] The present invention provides a depot composition comprising microspheres containing an oil layer (O layer) containing a biodegradable polymer and hydrophobic amino acids.

[0030] The depot composition of the present invention is a formulation capable of releasing a drug over a long period of time, and is a sustained-release formulation, or more specifically, a sustained-release injectable formulation. A sustained-release formulation must release the drug inside at an intended level gradually over a certain period of time. To this end, it is necessary to control the initial burst, in which an excessive amount of drug inside is released at the beginning of the depot injection, and to ensure that the suspension is well established before the depot injection. In the present invention, the initial burst is controlled by mixing hydrophobic amino acids, thereby producing microspheres with excellent suspension ability and completing the depot composition.

[0031] The microspheres of the present invention may be in an O / W configuration, comprising a single aqueous layer (W layer) and a single oil layer (O layer). Alternatively, the microspheres of the present invention may be in a W / O / W configuration, comprising an aqueous layer (W layer), an oil layer (O layer), and an aqueous layer (W layer).

[0032] In this specification, for the convenience of explanation, when there are two or more aqueous phase layers or aqueous solutions, the aqueous phase layer located inside the oil layer of a microsphere or the aqueous phase solution for forming it may be referred to as the first aqueous phase layer (W1 layer) or first aqueous phase solution, and the aqueous phase layer formed on the outer edge of the oil layer of a microsphere or the aqueous phase solution for forming it may be referred to as the second aqueous phase layer (W2 layer) or second aqueous phase solution. In this case, the aqueous phase layer (W layer) or aqueous phase solution in an O / W microsphere is understood to correspond to the second aqueous phase layer (W2 layer) or second aqueous phase solution in a W1 / O / W2 microsphere. Therefore, the O / W emulsion may also be referred to as an O / W2 emulsion in this specification, and in the following description, what is referred to as the second aqueous phase layer (W2 layer) or second aqueous phase solution should be understood in the same way as the description corresponding to the aqueous phase layer or aqueous phase solution for an O / W microsphere.

[0033] The microspheres can be produced by a single emulsification method, in which an oil-phase solution containing a biodegradable polymer and hydrophobic amino acids is added to an aqueous-phase solution and emulsified to produce an O / W emulsion. Alternatively, they can be produced by a double emulsification method, in which a W / O emulsion is added to an aqueous-phase solution and re-emulsified to produce a W / O / W emulsion.

[0034] Specifically, the microspheres of the present invention are prepared by dissolving hydrophobic amino acids and biodegradable polymers in a lipid-soluble solvent to produce an oil phase (O) solution, or by mixing a first aqueous phase (W1) solution prepared by dissolving the active ingredients in a water-soluble solvent with the oil phase (O) solution prepared by dissolving the hydrophobic amino acids and biodegradable polymers in a lipid-soluble solvent to produce a W1 / O emulsion;

[0035] The emulsion may also be produced by adding the oil phase solution or W1 / O emulsion to a second aqueous phase (Water phase 2: W2) solution containing an aqueous phase solvent.

[0036] The lipid-soluble solvent of the present invention can be any carrier or solvent that is commonly used in the art of the present invention and is pharmaceutically acceptable. For example, dichloromethane can be used, but is not limited thereto.

[0037] In the present invention, the water-soluble solvent can be any carrier or solvent that is commonly used in the art of the present invention and is pharmaceutically acceptable. For example, polyvinyl alcohol (PVA) or sodium acetate can be used, but are not limited thereto. The second aqueous solution may additionally contain an osmotic regulator such as sodium chloride to adjust the osmotic pressure of the solution during the emulsion manufacturing process.

[0038] The microspheres of the present invention may further contain hydrophobic amino acids in the aqueous phase layer. The aqueous phase layer may also be a second aqueous phase layer. Specifically, the microspheres can be produced by adding the oil phase solution or W1 / O emulsion to an aqueous phase solution prepared by dissolving hydrophobic amino acids in an aqueous phase solvent.

[0039] In this invention, when both the oil layer and the aqueous phase layer of the microspheres contain hydrophobic amino acids, the initial release suppression effect, which inhibits the excessive release of the active ingredient from inside the microspheres, is significantly improved, and the suspension ability of the depot composition is also significantly enhanced, allowing for effective use as an injectable agent.

[0040] The fine particles of the present invention may have a bulk density (BD) value of 0.1 g / ml or higher.

[0041] The bulk density (BD) mentioned above refers to the density based on the volume including the voids between particles when a powder or granular material is filled into a specific container. If the bulk density of microspheres in a depot composition is less than 0.1 g / ml, the microspheres are excessively light and difficult to use as an injectable agent. In particular, the bulky characteristics of the microspheres cause problems with dispersion in water for injection during resuspension. The microspheres of the present invention have a bulk density of 0.1 g / ml or more, exhibit excellent resuspension ability, and have excellent properties as an injectable agent.

[0042] The microspheres of the present invention can have a zeta potential value of -8mV or less.

[0043] The zeta potential, as mentioned above, represents the magnitude of the repulsive and attractive forces between particles in units, and the microspheres of the present invention can have a zeta potential of -8mV or less. If the zeta potential value exceeds -8mV, the microspheres in question may have reduced dispersibility and may settle rapidly in water for injection.

[0044] Preferably, the microspheres have a zeta potential value of -8mV to -40mV or -10mV to -30mV. When the above range is satisfied, the microspheres have excellent dispersibility and can be well suspended in water for injection, in which case a uniform depot solution can be formed, thus providing particularly excellent properties as an injectable formulation.

[0045] The microspheres of the present invention further contain an active ingredient. That is, since the depot composition of the present invention is administered into the body and releases the active ingredient into the body for a certain period of time, the depot composition may contain an active ingredient inside. In particular, the active ingredient may be contained inside the microspheres, protected from the microspheres, and remain in the body for a certain period of time.

[0046] The active ingredient may be contained in the first aqueous phase layer (W1 layer) or the oil phase (O layer) of the microspheres of the present invention. Typically, in the case of a single emulsion, the active ingredient may be contained in the oil layer, and in the case of a double emulsion, it may be contained in the first aqueous phase layer.

[0047] The active ingredient used for release in the present invention may preferably be a drug that treats a specific disease, symptom, or illness, and more preferably a biopharmaceutical or peptide drug. Specific examples of such drugs may be liraglutide or semaglutide.

[0048] Liraglutide or semaglutide are GLP-1 agonists that are involved in the action of GLP-1 (glucagon-like peptide-1), a hormone that lowers blood sugar, and may be used to treat obesity or diabetes. If the body is exposed to an excessive amount of liraglutide or semaglutide, symptoms such as vomiting, nausea, hypoglycemia, and headache may occur.

[0049] Therefore, when a depot composition contains liraglutide or semaglutide as the active ingredient, it is extremely important to prevent excessive release of the active ingredient from the depot preparation. Furthermore, since liraglutide or semaglutide are difficult to store and preserve as peptide drugs, one method to solve this is to dry the depot composition and store it in powder form. In this case, it is necessary to suspend the powder in sterile water for injection for injection, but if the powder's suspension ability is poor, it is not possible to form a uniform formulation, the uniformity of the drug effect will decrease, and clumps of microspheres and sediment may occur, or floating microspheres may occur, making it difficult to ensure control of the initial release. Therefore, when a formulation contains liraglutide or semaglutide as the active ingredient, it is extremely important to create a formulation that suppresses initial release and has excellent suspension ability.

[0050] To provide a depot composition having such initial release control capability, the present invention provides a depot composition in which the oil layer (O layer) of microspheres contains a biodegradable polymer and a hydrophobic amino acid.

[0051] The hydrophobic amino acid is an amino acid that does not have a polar portion and can be selected from the group consisting of valine, methionine, alanine, phenylalanine, tryptophan, isoleucine, and leucine. Leucine is preferred. When the oil layer of the microspheres of the present invention contains a hydrophobic amino acid, the hydrophobic amino acid reduces the pores on the surface of the microspheres, and due to the water-incompatible properties of the hydrophobic amino acid present in the O layer, the release of the active ingredient present in the first aqueous phase layer or oil layer to the outside of the oil layer can be partially suppressed, thereby controlling the initial release.

[0052] When the hydrophobic amino acid is contained only in the first aqueous phase, it is not possible to effectively suppress the initial release of an excessive amount of the active ingredient. When it is contained only in the second aqueous phase, the use of an excessive amount of raw material chemical (hydrophobic amino acid) leads to problems in the manufacturing process and increased process costs due to increased dissolution time and higher raw material costs. In contrast, when it is contained in the oil layer or in both the oil layer and the second aqueous phase, an effective initial release control effect can be obtained even with a low content of hydrophobic amino acid, and it has the advantage of significantly improving the suspension ability of the depot agent.

[0053] The microspheres may be manufactured by adding less than 1.5 parts by weight of hydrophobic amino acids to 100 parts by weight of biodegradable polymer in the oil phase solution. When 1.5 parts by weight or more of hydrophobic amino acids are mixed, there is a problem that the surface of the microspheres becomes non-uniform, reducing the uniformity of the depot drug.

[0054] More specifically, the microspheres may be manufactured by adding more than 0.07 parts by weight to 1.1 parts by weight or 0.3 parts by weight to 1.1 parts by weight of hydrophobic amino acids per 100 parts by weight of biodegradable polymer in the oil phase solution. In this case, the microspheres exhibit excellent initial release suppression effects of the active ingredient.

[0055] From this perspective, the microspheres of the present invention may contain hydrophobic amino acids in the oil layer in amounts of less than 1.5 parts by weight; more than 0.07 parts by weight to 1.1 parts by weight; or 0.3 parts by weight to 1.1 parts by weight per 100 parts by weight of biodegradable polymer. When hydrophobic amino acids are contained in the oil layer in amounts of 1.5 parts by weight or more per 100 parts by weight of polymer, there is a problem that the surface of the microspheres becomes non-uniform, reducing the uniformity of the depot drug. Also, when hydrophobic amino acids are contained only in the oil layer, if the amount of hydrophobic amino acids is 0.07 parts by weight or less, the initial release control effect by the hydrophobic amino acids is negligible.

[0056] Furthermore, the microspheres of the present invention may be manufactured by containing hydrophobic amino acids at a concentration of 0.05% (w / v) to 25% (w / v) of the entire aqueous phase solution containing a water-soluble solvent and hydrophobic amino acids. If the aqueous phase contains less than 0.05% (w / v) of hydrophobic amino acids, the bulk density of the microspheres becomes excessively low, making them unsuitable for use as an injectable formulation.

[0057] The biodegradable polymer has the property of being broken down in living organisms and, in this invention, has the property of forming microspheres. As the biodegradable polymer is slowly broken down, the drug contained inside can be slowly released. In other words, it protects the drug inside during the drug release period and controls drug release over a long period of time.

[0058] Specifically, any biodegradable polymer approved by the drug safety authorities of each country for use in injectable formulations may be used without limitation in the present invention.

[0059] The biodegradable polymer may have an inherent viscosity of 0.35 dL / g to 0.65 dL / g, preferably 0.50 dL / g to 0.55 dL / g. If the inherent viscosity is less than 0.35 dL / g, drug release may occur faster than the desired period, and if the inherent viscosity exceeds 0.65 dL / g, drug release may occur slower than the desired period, making it difficult to obtain a sufficient drug effect. As a preferred example, a polymer with a viscosity of 0.53 dL / g is used to maintain optimal drug persistence; in this case, the drug release characteristics are maintained for a long period as a depot composition, enabling bioavailability. The inherent viscosity can be measured by the viscosity measurement method for polylactic acid-glycolic acid copolymer (Polylactide-co-glycolide, PLGA) provided by the manufacturer.

[0060] Specifically, the biodegradable polymer may be a polymer containing lactide and glycolide as monomers. All polymers containing lactide and glycolide as monomers, regardless of their polymerized form, are included in the present invention. This also includes branched polymers in which the ends of the polymer are modified. Examples of such polymers include, but are not limited to, those selected from the group consisting of polylactic acid (PLA), polyglycolide (PGA), polylactic acid-glycolide copolymer (PLGA), and glucose-PLGA. In this respect, the microspheres of the present invention can be referred to as PLGA microspheres.

[0061] The biodegradable polymer may have the following molecular weight distribution content for each of these molecular weights determined by gel permeation chromatography analysis: 3% or more for the 500-4,000 molecular weight range, 10% or more and less than 30% for the 5,000-16,000 molecular weight range, 20% or more and less than 50% for the 16,000-40,000 molecular weight range, and 20% or more for 40,000 and above.

[0062] The depot composition of the present invention may further contain pharmaceutically acceptable carriers or excipients. However, preferably, the depot composition of the present invention does not contain stabilizers, pH adjusters, or oxidizing agents.

[0063] Furthermore, the present invention provides a method for producing a depot composition, comprising the steps of: preparing an oil phase (O) solution containing hydrophobic amino acids and biodegradable polymers; or preparing a W1 / O emulsion by mixing a first aqueous phase (W1) solution containing a water-soluble solvent with the oil phase (O) solution; and adding the oil phase solution or W1 / O emulsion to a second aqueous phase (W2) solution to produce an O / W2 emulsion or a W1 / O / W2 emulsion.

[0064] The process may further include a step of drying and / or filtering the manufactured emulsion and then centrifuging it to recover the microspheres.

[0065] The first aqueous phase (Water phase 1:W1) solution can be prepared by dissolving the active ingredient in a water-soluble solvent. In this invention, the water-soluble solvent can be any carrier or solvent that is commonly used in the art of this invention and is pharmaceutically acceptable. For example, polyvinyl alcohol (PVA) or sodium acetate can be used, but are not limited to these.

[0066] The aforementioned active ingredient means a drug intended to be released in the depot composition of the present invention, and is not limited to any type that can be used in the present invention. Specifically, it may be a water-soluble drug, a biopharmaceutical, or a peptide drug. For example, it may be liraglutide or semaglutide.

[0067] The oil phase (O) solution can be prepared by mixing and dissolving a biodegradable polymer and hydrophobic amino acids in a lipid-soluble solvent. The active ingredient can also be mixed and dissolved in the oil phase solution. In particular, in the case of microspheres produced by a single emulsification method, an emulsion can be produced by adding the oil phase solution containing the active ingredient to the aqueous phase solution.

[0068] The solvent used to incorporate the active ingredient into the oil phase solution can be a solvent commonly used in the technical field of the present invention.

[0069] The lipid-soluble solvent of the present invention can be any carrier or solvent that is commonly used in the art of the present invention and is pharmaceutically acceptable. For example, dichloromethane can be used, but is not limited thereto.

[0070] The hydrophobic amino acid may be present in the oil phase solution in an amount of less than 1.5 parts by weight per 100 parts by weight of the biodegradable polymer. If the hydrophobic amino acid is present in 1.5 parts by weight or more in the oil phase solution, the surface of the microspheres becomes non-uniform, which reduces the uniformity of the depot agent drug. Furthermore, if the hydrophobic amino acid is present in the oil solution alone, if the amount is less than 0.07 parts by weight, the initial release control effect of the hydrophobic amino acid is negligible.

[0071] The O / W emulsion can be produced by mixing the oil phase with the aqueous phase and stirring with a homogenizer. The stirring speed and time can be varied depending on the emulsion formation conditions and the amount of sample.

[0072] The aforementioned second aqueous phase (Water phase 2:W2) solution can be prepared by including a water-soluble solvent.

[0073] In the present invention, the water-soluble solvent can be any carrier or solvent that is commonly used in the art of the present invention and is pharmaceutically acceptable. For example, polyvinyl alcohol (PVA) or sodium acetate can be used, but are not limited thereto. The second aqueous solution may additionally contain an osmotic regulator such as sodium chloride to adjust the osmotic pressure of the solution during the emulsion manufacturing process.

[0074] Furthermore, the water-soluble solvent may further include polyvinyl alcohol, methylcellulose, polyvinylpyrrolidone, carboxymethylcellulose, lecithin, gelatin, polyoxyethylene, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene castor oil derivatives, and mixtures thereof.

[0075] Furthermore, the hydrophobic amino acid may be present in an amount of 0.05% (w / v) to 25.0% (w / v) relative to the entire second aqueous solution. If the second aqueous solution contains less than 0.005% (w / v) of hydrophobic amino acids, the bulk density of the microspheres becomes excessively low, making it unsuitable for use in injectable formulations.

[0076] Furthermore, the present invention provides a depot composition containing microspheres produced by the manufacturing method described above. In this case, a depot composition can be obtained that is excellent in suppressing the initial release of the active ingredient within the microspheres and has excellent suspension ability.

[0077] The present invention will be described in detail below through manufacturing examples and experimental examples. The following examples and experimental examples are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

[0078] <Preparation example: Preparation for the test and manufacturing of microspheres>

[0079] Manufacturing Example 1-1. Manufacturing of Microspheres

[0080] As an API, 252 mg of liraglutide (polypeptide laboratories) or semaglutide was dissolved in 1.2 mL of 1 wt% sodium acetate (Daejung Chemicals & Metals Co. Ltd.) to prepare the first aqueous phase (W1) solution.

[0081] 1350 mg of DL-lactic acid-glycolic acid copolymer (Poly D,L-lactide-co-glycolide; Resomer select 5545 DLG 5Glu, Evonik; Inherent Viscosity 0.53 dl / g) was dissolved in 5 mL of dichloromethane (Honeywell) to prepare the oil phase (O) solution. The W1 and O solutions were mixed and stirred in a homogenizer at 9000 rpm for 2 minutes to produce a W1 / O emulsion.

[0082] Next, 0.5 g of sodium chloride (NaCl; Daejung Chemicals & Metals Co. Ltd.) was dissolved in 100 mL of 1 wt% polyvinyl alcohol (PVA; Gohsenol EG-40P, Nippon Gohsei) solution to prepare the Water Phase 2 (W2) solution. The W1 / O emulsion was injected into W2 at a rate of 5 ml / min while being stirred at 9000 rpm with a homogenizer to produce the W1 / O / W2 emulsion. The prepared W1 / O / W2 emulsion was dried in water at room temperature for 3 hours, filtered through a sieve with a mesh size of 75 μm, and then centrifuged to collect the microspheres. The collected microspheres were redispersed in distilled water and then washed three times by centrifugation. The washed microspheres were freeze-dried to obtain the final microspheres containing the drug.

[0083] The microspheres produced by the above method were used as a control group for the microspheres of the present invention in the following experiments.

[0084] Production Example 1-2. Production of microspheres containing hydrophobic amino acids

[0085] To control the initial release in a sustained-release formulation, microspheres containing hydrophobic amino acids were manufactured, and their release-controlling effect was confirmed. The hydrophobic amino acids used were valine, methionine, phenylalanine, tryptophan, or leucine.

[0086] Aside from mixing hydrophobic amino acids into the first aqueous phase (Water phase 1:W1) solution, the oil phase (O) solution, and / or the second aqueous phase (Water phase 2:W2) solution, the microspheres were produced under the same conditions as in Production Example 1.

[0087] When hydrophobic amino acids were included in the first aqueous phase (Water phase 1:W1) solution or the oil phase (O) solution, they were mixed in a 1:1 molar ratio with respect to the main component (liraglutide or semaglutide). When hydrophobic amino acids were mixed in the second aqueous phase (Water phase 2:W2) solution, they were mixed at the same concentration as sodium chloride (NaCl). The specific manufacturing formulations varied for each experiment.

[0088] <Testing Method>

[0089] 1. Evaluation of liraglutide or semaglutide content

[0090] 20 mg of microspheres were placed in a 20 mL volume flask and dissolved in 10 mL of acetonitrile. The solution was then marked with 1 wt% sodium acetate solution, filtered through a 0.45 syringe filter, and the amount of liraglutide or semaglutide was quantified by high-performance liquid chromatography. The analytical conditions were as follows: a solvent mixture of 0.05 M potassium phosphate monobasic and acetonitrile in a 53:47 ratio was used as the mobile phase, and the measurement was performed using an Aegispak C18-L column at 215 nm with a flow rate of 1.0 mL / min.

[0091] 2. Release Test

[0092] 20 mg of lyophilized microspheres were released using a DISTEK Dissolution System 2500 at 120 rpm and 37°C with 100 mL of phosphate buffer (1X PBS) containing 0.05% Polysorbate 80. After collecting 2 mL of the sample, the upper layer and microspheres were separated by centrifugation, and the amount of lilaglutide or semaglutide present in the upper layer was quantified by high-performance liquid chromatography. The analytical conditions were as follows: a solvent mixture of 0.05 M potassium phosphate monobasic and acetonitrile in a 53:47 ratio was used as the mobile phase, and the measurement was performed using an Aegispak C18-L column at 215 nm with a flow rate of 1.0 mL / min.

[0093] For initial drug release in microspheres, the amount of liraglutide released over one hour using the method described above was confirmed, and for long-term release, the amount of liraglutide released over 35 days was confirmed.

[0094] 3. SEM measurement

[0095] Approximately 10 mg of microspheres were immobilized on an aluminum stub, coated with platinum under a vacuum of 0.1 torr and high voltage (10 kV) for 3 minutes, and then mounted on a SEM powder. The surface of the microspheres was then observed using an image analysis program.

[0096] 4. Measurement of particle size

[0097] The size of the microspheres was measured using a Malvern Mastersizer. Approximately 30 mg of microspheres were suspended in 5 ml of distilled water, and the suspension was placed in a dispersion apparatus. After dispersion at 2800 rpm and 50% Ultrasound for 1 minute, the size was measured.

[0098] 5. Measurement of suspension density

[0099] To confirm that the microspheres of the present invention disperse well when resuspended in an injection solvent, the density of the suspension was checked. The density of the suspension was measured using a Mettler-Toledo D5 instrument. 534 mg of microspheres were suspended in 2 ml of solvent and injected into a cell in the instrument to measure the density.

[0100] The standard value for suspension density is 1.01 g / cm³, which is the suspension density of untreated microspheres. 3 This was used as the basis for verification.

[0101] 6. Measurement of Zeta-potential

[0102] 50 mg of microspheres were dispersed in 3 ml of purified water, and the zeta potential was measured using Malvern's Nano-ZS equipment.

[0103] 7. Measurement of bulk density

[0104] After filling an Ependorp tube with 1 ml of microspheres, the mass of the filled microspheres was measured.

[0105] 8.DSC measurement

[0106] DSC measurements were performed using a differential scanning calorimeter. 5-10 mg of each microsphere was placed on an aluminum sample pan, and measurements were taken at 5°C / min from 25°C to 250°C.

[0107] <Test Example 1: Confirmation of the effect of controlling initial release by mixing hydrophobic amino acids>

[0108] Experiments were conducted to confirm whether hydrophobic amino acids can control the excessive release of drugs in microspheres. Microspheres containing hydrophobic amino acids were produced by mixing leucine as a hydrophobic amino acid into the first aqueous phase (Water phase 1:W1), oil phase (O), and / or second aqueous phase (Water phase 2:W2) solutions at each stage of microsphere production, using the same method as the microsphere production method described in Production Example 1, and producing emulsions. The specific production conditions were the same as those for the microsphere production method in Production Example 1, except for mixing hydrophobic amino acids into each solution.

[0109] When hydrophobic amino acids were included in the first aqueous phase (Water phase 1:W1) solution or the oil phase (O) solution, they were mixed in a 1:1 molar ratio with respect to the main component (liraglutide or semaglutide). When hydrophobic amino acids were mixed in the second aqueous phase (Water phase 2:W2) solution, they were mixed at the same concentration as sodium chloride (NaCl). The specific formulation for producing microspheres is shown in Table 1.

[0110] [Table 1]

[0111] To confirm the initial release suppression effect in the following microspheres: one without hydrophobic amino acids (Comparative Example 1), one with leucine mixed in the first aqueous solution (Example 1-1), one with leucine mixed in the second aqueous solution (Example 1-2), one with leucine mixed in the oil phase solution (Example 1-3), and one with leucine simultaneously mixed in the oil phase and second aqueous solution (Example 1-4), the content and release rate of lilaglutide (API) were confirmed under the conditions of Test Methods 1 and 2. The surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 2 and Figures 1(a) to 1(e).

[0112] Furthermore, in order to confirm the initial release suppression effect of semaglutide on microspheres that do not contain hydrophobic amino acids (Comparative Example S-1) and on microspheres in which leucine was simultaneously mixed in the oil phase solution and the second aqueous phase solution (Example S-1), the content and release rate of semaglutide (API) were confirmed under the conditions of Test Methods 1 and 2, and the surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 2 and in Figures 1(f) and 1(g).

[0113] [Table 2]

[0114] As shown in Table 2 and Figures 1(a) to 1(g), the microspheres of Comparative Example 1 and Comparative Example S-1 had many pores on their surfaces, which confirmed that this resulted in a large initial release of API. Furthermore, even in the case of microspheres containing leucine in the first aqueous phase layer (Example 1-1), the effect of covering the pores could not be obtained, and therefore the initial release suppression effect could not be obtained.

[0115] However, when leucine is included in the oil phase layer (O) and / or the second aqueous phase layer (W2), it is found that the pores of the microspheres are covered and almost no surface pores are observed. Specifically, when leucine is included only in the oil phase layer (Examples 1-3), the properties of the microspheres themselves are somewhat poor, but when leucine is included in both the oil phase layer and the second aqueous phase layer (Examples 1-4 and S-1), it was confirmed that it has an effect of suppressing the initial release of API and that the properties are also good.

[0116] <Experimental Example 2: Confirmation of the effect of controlling initial release depending on the type of hydrophobic amino acid>

[0117] To confirm whether hydrophobic amino acids other than leucine can similarly suppress the initial release of microspheres, we examined the release of the API, liraglutide, in microspheres produced by mixing valine, methionine, phenylalanine, tryptophan, and leucine during the microsphere manufacturing process.

[0118] Microspheres were produced in the same manner as in Comparative Example 1, but with different hydrophobic amino acids mixed into the oil phase (O) solution and the second aqueous phase (W2) solution during the microsphere production stage to produce microspheres containing hydrophobic amino acids. Aside from mixing hydrophobic amino acids into each solution, the specific production conditions were the same as in Comparative Example 1.

[0119] In the oil phase (O) solution, hydrophobic amino acids were mixed with the main component (liraglutide) in a 1:1 molar ratio. In the water phase 2 (W2) solution, each hydrophobic amino acid was mixed with sodium chloride at the same concentration. The specific formulation for producing microspheres is shown in Table 3 below.

[0120] [Table 3]

[0121] To confirm the initial release inhibitory effect in microspheres without hydrophobic amino acids (Comparative Example 1), microspheres containing valine (Example 2-1), microspheres containing methionine (Example 2-2), microspheres containing phenylalanine (Example 2-3), microspheres containing tryptophan (Example 2-4), and microspheres containing leucine (Example 2-5) as shown in Table 3, the content and release rate of liraglutide (API) were confirmed under the conditions of Test Methods 1 and 2. The surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 4 and Figures 2(a) to 2(e).

[0122] [Table 4]

[0123] As shown in Table 4 and Figures 2(a) to 2(e), compared to the surface and API release amount of the microspheres in Comparative Example 1 (Figure 1(a)), it was confirmed that pore size decreased in all microspheres containing valine, methionine, phenylalanine, tryptophan, or leucine (Examples 2-1 to 2-5), and that the initial release of API (liraglutide) was also suppressed. This means that when microspheres are manufactured so that hydrophobic amino acids are included in the oil phase and W2, the hydrophobic amino acids can act to suppress the release of microspheres.

[0124] <Test Example 3: Confirmation of the difference between microsphere coating and initial release inhibition effect>

[0125] We investigated whether initial release could be suppressed when the microspheres were coated with hydrophobic amino acids after production, compared to when the microspheres contained hydrophobic amino acids inside the microspheres.

[0126] Specifically, the manufacturing formulation was as shown in Table 5, and microspheres were produced using the conditions and methods described in Manufacturing Example 1 (Comparative Example 2). The microspheres produced in Comparative Example 2 were then suspended again in leucine solution and freeze-dried (Comparative Example 3). The leucine solution was prepared by mixing 0.5 g of leucine per 1 g of microspheres, maintaining the suspension for 10 minutes, and then freeze-drying.

[0127] [Table 5]

[0128] To confirm the initial release suppression effect on the microspheres of Comparative Examples 2 and 3 produced, the content and release rate of liraglutide (API) were confirmed under the conditions of Test Methods 1 and 2, and the surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 6 and Figures 3(a) and 3(b).

[0129] [Table 6]

[0130] As shown in Table 6 and Figures 3(a) and 3(b), when microspheres are simply coated with hydrophobic amino acids (Comparative Example 3), the effect of suppressing release cannot be obtained compared to uncoated microspheres (Comparative Example 2), and in fact, the amount of release increases even further. Therefore, it can be seen that the release suppression effect obtained from microspheres containing hydrophobic amino acids in the present invention is a unique effect that can be obtained by controlling the pores and surface of the microspheres with hydrophobic amino acids during the emulsion manufacturing stage.

[0131] <Test Example 4: Confirmation of the effect of controlling initial release by other types of hydrophobic substances>

[0132] To confirm whether the effect of the present invention on suppressing the initial release of hydrophobic amino acid microspheres can be obtained when using other substances, we investigated whether the initial release of microspheres can be suppressed using cholesterol, one of the hydrophobic substances, and DOTAP (Dioleoyl-3-trimethylammonium propane), a cationic lipid.

[0133] Microspheres were produced using the same method as in Comparative Example 1, but with cholesterol or DOTAP mixed into the oil phase (O) during the microsphere production stage, thereby producing microspheres containing cholesterol or DOTAP.

[0134] The oil phase (O) solution was prepared by mixing the main component (liraglutide) with either cholesterol or DOTAP in a 1:1 molar ratio. The specific formulation for producing microspheres is shown in Table 7 below.

[0135] [Table 7]

[0136] To confirm the release of liraglutide (API) in microspheres without hydrophobic amino acids (Comparative Example 1), microspheres containing cholesterol (Comparative Example 4-1), and microspheres containing DOTAP (Comparative Example 4-2) as shown in Table 7, the content and release rate of liraglutide (API) were confirmed under the conditions of Test Methods 1 and 2. The surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 8 and in Figures 4(a) and 4(b).

[0137] [Table 8]

[0138] As shown in Table 8 and Figures 4(a) and 4(b), when compared with the surface and API release amount of the microspheres of Comparative Example 1 (Figure 1(a)), it can be seen that Comparative Examples 4-1 and 4-2, which are microspheres containing cholesterol or DOTAP, either fail to suppress the initial release of API (liraglutide) or experience a decrease in API content. Furthermore, surface examination via SEM reveals that the microspheres have numerous pores or that the surface is not manufactured smoothly. Therefore, the above results indicate that the initial release suppression effect of the microspheres of the present invention is specific to PLGA microspheres and is due to the hydrophobic amino acids.

[0139] <Test Example 5: Confirmation of the effect of hydrophobic amino acid content on suppressing release control>

[0140] To confirm whether the effect of the microspheres of the present invention in suppressing drug release within the microspheres is due to the content of hydrophobic amino acids, the release of APIs in the microspheres and the properties of the microspheres were examined based on the content of hydrophobic amino acids.

[0141] Leucine was used as the hydrophobic amino acid, and microspheres were produced using the method described in Comparative Example 1, with the only difference being that leucine was mixed during the production of the oil phase and / or the second aqueous phase. Microspheres without hydrophobic amino acids (Comparative Example 5) were also produced and used as a control group. The formulations for producing microspheres for each test group, as well as the specific content and mixing steps of the release control component, are as shown in Table 9. The content of the release control component is expressed as the percentage (w / w) of the release control component relative to the content of the biodegradable polymer (PLGA) that forms the microspheres.

[0142] [Table 9]

[0143] To confirm the release of lilaglutide (API) in microspheres that do not contain hydrophobic amino acids (Comparative Example 5), microspheres containing leucine in the oil layer (Examples 3-1, 3-2, and 3-3), and microspheres containing leucine in both the oil layer and the W2 layer (Examples 4-1, 4-2, 4-3, and 4-4), the content and release rate of lilaglutide (API) were confirmed under the conditions of Test Methods 1 and 2. The surface of the microspheres was observed using SEM images under the conditions of Test Methods 3 and 4, and the average particle size (D[4,3]) of each microsphere was measured. The results are shown in Table 10, Figures 5(a) to 5(c), and Figures 6(a) to 6(d).

[0144] [Table 10]

[0145] Furthermore, the physicochemical properties (bulk density (BD), suspension density, and zeta potential) of each microsphere were measured using test methods 5-8 and are shown in Table 11.

[0146] [Table 11]

[0147] As shown in Tables 10 and 11, respectively, it can be confirmed that the hydrophobic amino acid leucine in Examples 3-1 to 3-3 and Examples 4-1 to 4-4 has the effect of suppressing the initial release of APIs in microspheres contained in the O layer or the O layer and W2 layer. In particular, in the case of the microspheres of Example 3-2, it can be confirmed that they exhibit excellent suppression of API release and that the formulation has a uniform pattern on the surface and on the microspheres. Furthermore, in this case, the injectable dispersibility is good and the zeta potential is appropriate, so when the microspheres are suspended in sterile water for injection, they disperse well and have appropriate characteristics as an injectable formulation.

[0148] However, when leucine is included alone in the O layer, it was confirmed that the release control effect is slightly reduced when the leucine content relative to the polymer is 0.07% (w / w).

[0149] Furthermore, even when the O layer contains leucine, if the leucine content is 0.05% (w / v) or less relative to the total W2 aqueous phase solution, the bulk density (BD, g / ml) of the particles is excessively low, making it unsuitable for use as an injectable preparation.

[0150] However, in the case of the microspheres of Examples 4-1 and 4-2, it can be confirmed that the initial release of the API can be controlled more effectively by including all of the leucine in the O layer and W2 layer, and that a formulation with a very uniform microsphere pattern can be provided. In particular, it can be seen that the suspension density is appropriate, resulting in good injectable dispersibility and a significantly superior zeta potential value. This means that the microspheres have excellent dispersibility in water for injection, and that the microsphere formulation of the present invention has significantly superior properties as an injectable formulation.

[0151] Furthermore, as shown in Figure 7, DSC analysis results for the microspheres of Comparative Example 5, Comparative Example 4-2, and Example 4-1 confirmed that there was no change in the thermal behavior or crystal form of the polymer and drug even when leucine was included inside the microspheres.

[0152] Furthermore, as shown in Figure 8, the long-term release behavior of the microspheres of Comparative Example 5, Example 3-2, and Example 4-2 was observed for 35 days. The results confirmed that the microspheres of the present invention containing leucine maintained an initial elution rate of 5% or less within the first day of control and 15% or less for four days, while the drug was continuously released in a zero-order manner for four weeks. This demonstrates that the PLGA microspheres of the present invention, which contain leucine in the oil layer or the oil layer and W2 layer, exhibit excellent initial release suppression and sustained release maintenance effects, and possess excellent properties for use as a depot agent.

[0153] <Test Example 6: Confirmation of initial release control and sustained-release effect in vivo>

[0154] We conducted experiments to confirm the drug release behavior of microspheres in vivo.

[0155] Microspheres (28 mg / kg as liraglutide) prepared according to Examples 1-4 and Comparative Example 1 in Table 1 were subcutaneously administered to the backs of five 8-week-old male SD rats averaging 300 g. Blood samples were then collected at 0, 1, 2, 4, 8, 10, 12, 24, 48, 96, 168, 336, 504, 672, and 1008 hours.

[0156] Subsequently, the concentration of liraglutide in the blood of SD rat plasma samples was measured at various time points using enzyme-linked immunosorbent assay (ELISA). The GLP-1 (active) ELISA kit (IBL, Germany) was used.

[0157] Figure 9 shows the change in liraglutide concentration over time. The results in Figure 9 represent the average values ​​for the five rats used in the experiment.

[0158] As shown in Figure 9, the microspheres containing hydrophobic amino acids (Examples 1-4) showed a 4.4-fold reduction in the maximum blood concentration (Cmax) of physiologically active substances compared to the microspheres of Comparative Example 1, which have a general fine particle form, and demonstrated excellent sustained-release effects up to 42 days.

Claims

1. A depot composition comprising microspheres in an O / W2 configuration including an oil layer (O layer) and a second aqueous phase (Water phase 2: W2) layer, or microspheres in a W1 / O / W2 configuration including a first aqueous phase (Water phase 1: W1) layer, an oil layer, and a second aqueous phase layer, The oil layer of the O / W2 microspheres and the first aqueous layer of the W1 / O / W2 microspheres contain an active ingredient. The oil layer contains a biodegradable polymer and a hydrophobic amino acid. The biodegradable polymer is selected from the group consisting of polylactic acid (PLA), polyglycolic acid (PGA), polylactic acid-glycolic acid copolymer (PLGA), and Glucose-PLGA. The hydrophobic amino acid is selected from the group consisting of valine, methionine, alanine, phenylalanine, tryptophan, isoleucine, and leucine. A depot composition wherein the O / W2 microspheres and the W1 / O / W2 microspheres each independently contain hydrophobic amino acids in the oil layer at a concentration of less than 1.5 parts by weight per 100 parts by weight of the biodegradable polymer.

2. The depot composition according to claim 1, wherein the W1 / O / W2 microspheres further contain the hydrophobic amino acid in the second aqueous phase layer.

3. The depot composition according to claim 1 or claim 2, wherein the microspheres have a bulk density (BD) of 0.1 g / ml or more and a zeta potential of -8 mV to -30 mV.

4. The depot composition according to claim 2, wherein the W1 / O / W2 microspheres contain hydrophobic amino acids at an amount of 0.05% (w / v) to 25% (w / v) relative to the entire aqueous phase layer.

5. The depot composition according to claim 1, wherein the biodegradable polymer has an inherent viscosity (Inherent Viscosity / 25°C) of 0.35 dL / g to 0.65 dL / g.

6. The steps include: preparing an oil phase (O) solution containing hydrophobic amino acids and biodegradable polymers, or preparing a W1 / O emulsion by mixing a first aqueous phase (Water phase 1: W1) solution containing a water-soluble solvent with the oil phase (O) solution; and A method for producing a depot composition, comprising the step of adding the oil phase solution or W1 / O emulsion to a second aqueous phase (Water phase 2: W2) solution to produce an O / W2 emulsion or a W1 / O / W2 emulsion, The oil phase solution and the first aqueous phase solution of the W1 / O emulsion contain an active ingredient. The oil phase solution and the first aqueous phase solution of the W1 / O emulsion each independently contain hydrophobic amino acids in an amount of less than 1.5 parts by weight per 100 parts by weight of biodegradable polymer. The biodegradable polymer is selected from the group consisting of polylactic acid (PLA), polyglycolic acid (PGA), polylactic acid-glycolic acid copolymer (PLGA), and Glucose-PLGA. A method for producing a depot composition, wherein the hydrophobic amino acid is selected from the group consisting of valine, methionine, alanine, phenylalanine, tryptophan, isoleucine, and leucine.

7. The method for producing the depot composition according to claim 6, wherein the second aqueous phase (Water phase 2: W2) solution further comprises hydrophobic amino acids.

8. The method for producing the depot composition according to claim 7, wherein the hydrophobic amino acid is contained in an amount of 0.05% (w / v) to 25.0% (w / v) of the entire second aqueous solution.

9. A method for producing a depot composition according to claim 6 or 7, further comprising the step of drying and / or filtering the manufactured O / W2 emulsion or W1 / O / W2 emulsion and then centrifuging it to recover microspheres.

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