Stable AST-3424 bulk drug product, preparation method and storage thereof

Abstract

The invention discloses a stable AST-3424 raw material medicine product, a preparation method and storage thereof, the stable AST-3424 raw material medicine product provided by the invention is an ethanol solution of AST-3424, and the mass percent of the AST-3424 in the solution is 30-40%. The invention further provides a packaging unit of the product, the packaging unit comprises a container and the stable AST-3424 raw material medicine product contained in the container, the container is provided with a container body used for containing and a sealing structure used for sealing the container body, and the container body and the sealing structure are both made of high-density polyethylene materials at the medicinal level. Mixing the separated and purified oily AST-3424 product with absolute ethyl alcohol under the condition that the temperature does not exceed 30 DEG C, and performing reduced pressure distillation until the mass percent of the AST-3424 reaches a preset value to obtain the product. The product should be stored at-20 + / -5. And C, in a dark environment.

Description

Stable AST-3424 API product, preparation method, and storage Technical Field

[0001] The present invention relates to the raw material drug of the compound AST-3424 disclosed in patent application PCT / US2016 / 021581, publication number WO2016145092A1, corresponding Chinese application number 2016800150788, publication number CN107530556A, and belongs to the field of cancer treatment compound research and development. Background Art

[0002] Our company has developed a DNA alkylating cancer therapeutic drug AST-3424 that targets overexpressed aldehyde-keto reductase 1C3 (AKR1C3) (see patent application: DNA alkylating agent, corresponding to PCT application number PCT / US2016 / 021581, publication number WO2016 / 145092, corresponding to Chinese application number 2016800150788, publication number CN107530556A, and compound TH2870; (R)- and (S)-1-(3-(3-N,N-dimethylaminocarbonyl)phenoxy-4-nitrophenyl)-1-ethyl-N,N'-bis(ethylene)phosphoramidate). , compositions, uses thereof, and preparation methods thereof, corresponding to PCT application number PCT / US2016 / 062114, publication number WO2017087428A1, corresponding to Chinese application number 2016800446081, publication number CN108290911A (S-configured compound), Chinese name is (S)-1-(3-(3-N,N-dimethylaminocarbonyl)phenoxy-4-nitrophenyl)-1-ethyl-N,N'-bis(ethylene)phosphoramidate, also known as OBI-3424, S-configured compound of TH-2870), CAS number 2097713-69-2, and its structure is as follows:

[0003]

[0004] There are authoritative industry documents (Kathryn Evans, Jian Xin Duan, Tara Pritchard, et al. OBI-3424, a novel A KR1C3-activated prodrug, exhibits potent efficacy against preclinical models of T-ALL[J], Clinical Cancer Research, 2019, DOI: 10.1158 / 1078-0432.CCR-19-0551; Richard B.Lock,Kathryn Evans,Ray mond Yung,Tara Pritchard,Beverly A.Teicher,Jian Xin Duan,Yue long Guo,Stephen W.Ericksona and Malcolm A.Smith,Abstract LB-B16:The AKR1C3-Activated Prodrug OBI-3424 Exerts Profoun d In Vivo EfficacyAgainst Preclinical Models of T-Cell Acute Lymphoblastic Leukemia (T-ALL); a Pediatric Preclinical Testing Consortium Study [C], AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; October 26-30, 2017; Philadelphia, PA, DOI: 10.1158 / 1535-7163.) confirmed that the compound is a broad-spectrum small molecule anticancer prodrug with efficacy against a variety of solid tumors and hematological tumors.

[0005] In order to conduct subsequent clinical trials, a large amount of AST-3424 API needs to be prepared to prepare formulations for long-term clinical trials (2-5 years).

[0006] During the synthesis and preparation process, it was found that the substance was a light yellow oily liquid. The viscous, oily semi-liquid form of its raw material under normal conditions is quite different from the solid form of general raw materials, which causes great inconvenience in storage, transportation, packaging, subpackaging, and metering.

[0007] Summary of the Invention

[0008] After a long period of stability research, the inventors found that an ethanol solution with a mass percentage of AST-3424 of 30-40% has long-term stability under certain storage conditions and has suitable fluidity, which is convenient for storage, transportation, packaging, subpackaging, and metering, solving the problem that the AST-3424 compound itself is an oily viscous liquid.

[0009] Specifically, this application provides the following technical solutions.

[0010] A stable AST-3424 bulk drug product is an ethanol solution of AST-3424, wherein the mass percentage of AST-3424 in the solution is 25-70%, preferably 25-45%, and more preferably 30-40%.

[0011] In the preparation of AST-3424, in order to remove as much solvent and water as possible from the preparation and separation processes by distillation, the applicant mixed the separated and purified oily AST-3424 product with various commonly used solvents (ethyl acetate, ethanol, methanol, etc.), heated it at a relatively low temperature, and then distilled it under reduced pressure. It was found that ethanol could almost infinitely dissolve AST-3424, until the ethanol was evaporated to dryness, leaving only a thick, sticky oil of AST-3424. Although methanol also showed good solubility in several experiments, methanol is relatively toxic. Ethyl acetate does not have a high enough solubility, and ultimately, it was preliminarily decided to use ethanol.

[0012] Subsequent accelerated stability studies and stability studies under long-term storage conditions confirmed that a 30-40% by mass ethanol solution of AST-3424 had good storage stability and suitable high and low temperature impact stability and could be stored for a long time.

[0013] Based on the limited stability data currently available, the stability of the pure API is better than that of the AST-3424 ethanol solution, so it is very likely that the stability of the drug solution above 40% is also good. Based on existing test data and combined with the inventors' experience, good stability and suitable viscosity can still be maintained at up to 70% by mass.

[0014] Furthermore, the HPLC chemical purity test result of AST-3424 is greater than or equal to 98.0%, and the HPLC chemical content test result of the isomer is less than or equal to 2.0% (ie, the enantiomeric excess ee% ≥ 96.0%).

[0015] The AST-3424 compound was purified by chromatography and then assayed by conventional achiral HPLC with a 230 nm UV detector. The chemical purity of AST-3424, calculated by the area normalization method, was greater than or equal to 98.0% (see Figure 1). In practice, because the achiral columns used in conventional HPLC cannot separate AST-3424 from its isomer, AST-3423, some isomers are not detected by conventional achiral HPLC. Therefore, HPLC assays using a chiral column are necessary. The chemical content of the isomer, AST-3423, was less than or equal to 2.0% (i.e., enantiomeric excess (ee) % ≥ 96.0%, see Figure 2) as calculated by the area normalization method using a 230 nm UV detector.

[0016] After experiments, the shelf life of the stable AST-3424 raw material product is greater than or equal to 24 months when stored at -20±5℃ and protected from light.

[0017] After experiments, the shelf life of the stable AST-3424 raw material product is greater than or equal to 36 months when stored at -20±5℃ and protected from light.

[0018] After experiments, the shelf life of the stable AST-3424 raw material product is greater than or equal to 42 months when stored at -20±5℃ and protected from light.

[0019] Experiments under long-term storage conditions have shown that the AST-3424 raw material drug product in the above-mentioned solution state has a long shelf life, that is, its quality still meets the standards after being stored for a corresponding period of time.

[0020] A stable AST-3424 API product having a residual silver percentage by weight less than or equal to 15 parts per million.

[0021] In the preparation process of AST-3424 compound, AgNO3 or Ag2O is required as catalyst, so it is inevitable that residues will be produced in the AST-3424 raw material product. Considering that the aziridine ring structure of AST-3424 may be + The loop is opened under the action of Ag, so it is necessary to control + According to the provisions of ICH Q3C and experiments, when the residual silver mass percentage is less than or equal to 15 parts per million, i.e. 15 ppm, there is almost no effect on long-term storage. If a lower residual content is required, it is technically difficult to achieve (even if it can be achieved, the cost is high), and the shelf life of the product will not be extended much. Therefore, it is more appropriate to set the quality standard at 15 ppm.

[0022] Preferably, the mass percentage of AST-3424 in the solution is 35.4%-39.59%.

[0023] For stable AST-3424 API products, the residual solvent quality limit requirements in the solution are:

[0024] Acetone ≤ 5000ppm,

[0025] Ethyl acetate ≤ 5000ppm,

[0026] Tetrahydrofuran ≤ 720ppm,

[0027] Triethylamine ≤5000ppm,

[0028] Methanol ≤ 3000ppm,

[0029] n-heptane ≤ 5000ppm,

[0030] Dichloromethane ≤ 600ppm.

[0031] The stable AST-3424 API product does not contain any water and its water content is controlled within 1.0% by weight.

[0032] Obviously, not adding water means that no additional water is added during the preparation process, and other reagents, solvents, etc. used are anhydrous grade reagents, such as anhydrous ethanol, and water environment or contact with water is avoided as much as possible during the production process. That is to say, the water content needs to be controlled during the preparation of the raw material drug product of the present invention. In theory, the lower the water content, the better the stability. However, considering the technical difficulty and the realization of industrial mass production, the research and development team prefers a water content (determined by Karl Fischer method) within 1.0% by mass.

[0033] Obviously, the stable AST-3424 API product provided above needs to be designed with corresponding packaging during long-term storage, transportation or sales. Unlike the cardboard barrel packaging used for conventional solid APIs, since the AST-3424 API product is dissolved in an ethanol solution, it is an ethanol solution of appropriate concentration: an ethanol solution with too high a concentration has high viscosity and is not easy to transfer; an ethanol solution with too low a concentration means a high ethanol content, high volatility, large fluctuations in product content, reduced safety, and increased transportation risks. Correspondingly, in order to prevent it from deteriorating during storage, a specially designed packaging unit is required for packaging.

[0034] The packaging unit includes a container and the above-mentioned stable AST-3424 raw material drug product contained in the container. The container has a container body for containing the drug and a sealing structure for sealing the container body. The container body and the sealing structure are both made of pharmaceutical grade high-density polyethylene (HDPE).

[0035] Experiments have confirmed that using high-density polyethylene (HDPE) as a material in direct contact with the API solution is highly stable under storage conditions. When using pharmaceutical-grade HDPE, it is feasible to use appropriate packaging containers to contain the API solution. For example, if the API solution is packaged in a bottle, the corresponding sealing structure is a bottle cap; if the API solution is packaged in a bag, the corresponding sealing structure is a thermoplastic seal.

[0036] Furthermore, the packaging unit also includes a light-shielding structure, which wraps the container.

[0037] Correspondingly, the light-shielding structure may be an outer packaging, that is, an outer packaging made of a light-shielding material completely wraps the inner packaging. Correspondingly, aluminum cans, cardboard barrels, aluminum foil bags, etc. may be used for the outer packaging.

[0038] Preferably, the shading structure is an aluminum foil bag.

[0039] Furthermore, a method for preparing the above-mentioned raw material drug product solution is also provided.

[0040] Regardless of the process route used to prepare the AST-3424 compound, the final compound product must be purified. Since the AST-3424 compound is a viscous oil under normal conditions, chromatographic columns have been used for separation in previous literature. Therefore, there will be some residual solvents such as reaction solvent, chromatographic column mobile phase solvent, and water in the compound. Through experimental exploration, these residual solvents can be removed by adding ethanol to dissolve it and then evaporating it.

[0041] The invention relates to a method for preparing a stable AST-3424 raw material drug product, comprising mixing the separated and purified oily AST-3424 product with anhydrous ethanol at a temperature not exceeding 30° C., and then distilling the mixture under reduced pressure until the mass percentage of AST-3424 reaches a predetermined value.

[0042] Furthermore, the mixture was mixed with anhydrous ethanol and then subjected to reduced pressure distillation for three times, wherein the first two times the mixture was concentrated under reduced pressure until no fraction was left, and the third time the mixture was distilled under reduced pressure until the mass percentage of AST-3424 reached a predetermined value.

[0043] Preferably, the pressure of the reduced pressure distillation is a gauge pressure P≤-0.08MPa.

[0044] Furthermore, a storage method for the above-mentioned stable AST-3424 bulk drug product is provided, characterized in that it is stored in an environment of -20±5°C, preferably, it is stored in a light-proof environment of -20±5°C.

[0045] In particular, unless otherwise specified, all numerical values ​​in the specification have a range of ±10%. That is, if a numerical range in the specification is 2-3, then in fact, due to the existence of measurement errors, random errors, and systematic errors, if the actual measurement is 1.8-3.3, it should also be deemed to fall within the above-mentioned range of 2-3, which also meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG1 is a chiral HPLC chromatogram of the enantiomeric excess test of a sample of batch 034101 after 3 months of storage at 5±3°C in a long-term stability experiment;

[0047] FIG2 is a HPLC chromatogram of the chemical purity test of a sample of batch 034101 after one month of storage at 5±3°C in a long-term stability experiment;

[0048] Figure 3 is a comparison of the viscosity of a 30% AST-3424 ethanol solution and the AST-3424 API product. DETAILED DESCRIPTION

[0049] The stable AST-3424 API product of the present invention is essentially a 30-40% by mass ethanol solution of AST-3424. The use of the ethanol solution is based on experimental data on the solubility of AST-3424 and combined with long-term stability data of the solution. The specific experimental data are as follows.

[0050] 1. Solubility Study of AST-3424

[0051] 1.1 Solubility test

[0052] Take an appropriate amount of AST-3424 (hereinafter referred to as the API) and place it in a suitable container. Gradually add solvent and shake well. Observe the process of the solution from turbidity (presence of excess AST-3424 oil droplets) to clarity (AST-3424 is completely dissolved). Record the volume of solvent required to make the AST-3424 mixed solution clear and calculate the solubility.

[0053] 1.2 Test Results

[0054] Table 1: Solubility study results of AST-3424 (mg / ml)

[0055] Solvent Ethanol Propylene glycol Ethyl acetate Water solubility (mg / ml) > 1000 > 100 > 1000 About 20 Phenomenon Very soluble (mutually soluble) Very soluble (mutually soluble) Slightly soluble

[0056] Table 1 summarizes the solubility of AST-3424 in various alcoholic solvents at 25°C. Alcoholic solvents such as ethanol and propylene glycol exhibit good solubility for the API. Experiments using water also showed that AST-3424 is slightly soluble in water.

[0057] 1.3 Stability study

[0058] AST-3424 solutions (content of approximately 90 mg / ml) dissolved in different solvents were subjected to high-temperature destruction (40°C, 3 days) to test the purity and compare with undestroyed samples (40°C, 3 days) to investigate the stability of AST-3424 in different solvents.

[0059] Purity was determined using HPLC:

[0060] The UVDAD detector wavelength was 230 nm, the C18 column was used, and the column temperature was 25 °C.

[0061] Mobile phase:

[0062] A: 10 mmol / L ammonium acetate solution dissolved in a mixed solvent of 95% water and 5% acetonitrile by volume;

[0063] B: 8 mmol / L ammonium acetate solution dissolved in a mixed solvent of 95% acetonitrile and 5% water by volume;

[0064] Perform gradient elution.

[0065] Table 2: Chemical purity study results of AST-3424 solutions in different solvents after storage at 40°C for 3 days (mg / ml)

[0066]

[0067] AST-3424 has poor stability in water, but is relatively stable in anhydrous ethanol, propylene glycol, ethyl acetate and acetonitrile. The viscosity of AST-3424 dissolved in propylene glycol is significantly higher than that in other solvents.

[0068] AST-3424 is a viscous oily substance that is inconvenient to transfer and repack. It needs to be dissolved with a solvent to reduce the viscosity. See Figure 3 for details.

[0069] AST-3424 is an injectable API. Solvents that can be used for injections include water, anhydrous ethanol, and propylene glycol. Experiments have shown that AST-3424 has poor solubility and stability in water, but good solubility and stability in ethanol and propylene glycol. However, propylene glycol is not suitable due to its high viscosity, so anhydrous ethanol was ultimately chosen to dilute AST-3424 to a concentration of 30-40% by mass.

[0070] 2. Preparation and Stability Study of AST-3424 API Ethanol Solution

[0071] 2.1 Preparation

[0072] The disclosed process ((R)- and (S)-1-(3-(3-N,N-dimethylaminocarbonyl)phenoxy-4-nitrophenyl)-1-ethyl-N,N'-bis(ethyl)amino phosphate, composition, use and preparation method thereof, corresponding to PCT application number PCT / US2016 / 062114, publication number WO2017087428A1, corresponding to Chinese application number 2016800446081, publication number CN108290911A, S-configuration compound TH3424) is synthesized and prepared. After obtaining a yellow oil by silica gel column chromatography, the obtained oily mixture is mixed with anhydrous ethanol (pharmaceutical grade) and then distilled under reduced pressure until the mass percentage of AST-3424 reaches a predetermined value to obtain an AST-3424 raw material drug product solution. The temperature of the reduced pressure distillation shall not exceed 30° C., and the pressure of the reduced pressure distillation shall be a gauge pressure P≤-0.08 MPa.

[0073] The mixture was then subjected to three vacuum distillation operations after mixing with anhydrous ethanol. The first two vacuum concentration operations were performed until no fraction remained, and the third vacuum distillation operation was performed until the mass percentage of AST-3424 reached a predetermined value. The predetermined mass percentage of AST-342 in the solution was 30-40%, preferably 35.4%-39.59%. These values ​​were quantitatively determined by the HPLC external standard method (HPLC method is the method in Section 1.3).

[0074] The HPLC chemical purity test result of the solution AST-3424 is greater than or equal to 98.0%, and the HPLC chemical content test result of the isomer is less than or equal to 2.0% (ee% is greater than or equal to 96%).

[0075] The chemical purity was determined by HPLC (HPLC method is the method in Section 1.3) and calculated using the area normalization method.

[0076] AST-3424 is S-configuration, and its chemical structure is

[0077] Its enantiomer is R-configuration, namely AST-3423 (i.e. PCT / US2016 / 021581, Publication No. WO2016145092A1, corresponding to TH-3423 in Chinese Application No. 2016800150788, Publication No. CN107530556A), and its chemical structure is ), and its chemical content detection (using chiral HPLC) is less than or equal to 2.0% (using area normalization method).

[0078] The final mixture is sampled and analyzed to confirm that the solvent residues in the final product meet the following requirements:

[0079] Acetone ≤ 5000ppm,

[0080] Ethyl acetate ≤ 5000ppm,

[0081] Tetrahydrofuran ≤ 720ppm,

[0082] Triethylamine ≤5000ppm,

[0083] Methanol ≤ 3000ppm,

[0084] n-heptane ≤ 5000ppm,

[0085] Dichloromethane ≤ 600ppm.

[0086] In particular, the residual silver mass percentage is less than or equal to 15 parts per million.

[0087] The above solvent residues were detected by GC using the method in the Chinese Pharmacopoeia.

[0088] The residual silver mass was determined by ICP-MS using the method in the Chinese Pharmacopoeia.

[0089] 2.2 Preliminary stability studies at different storage temperatures, in the dark, and under light

[0090] Using the above preparation method, distillation was performed until the final volume was 0.5 to 1 L. Three batches were prepared (under GMP conditions). The data for each batch are as follows:

[0091] Batch 024101, equivalent to 0.32 kg of AST-3424 (0.8938 kg of a 35.8% ethanol solution), packaged in HDPE bottles with screw caps and packaged in LDPE bags with aluminum foil;

[0092] Batch 034101, equivalent to 0.35 kg of AST-3424 (0.9668 kg of a 36.2% ethanol solution), packaged in HDPE bottles with screw caps and packaged in LDPE bags with aluminum foil;

[0093] Batch 044101, equivalent to 0.31 kg of AST-3424 (0.8732 kg of a 35.5% ethanol solution), packaged in HDPE bottles with screw caps and packaged in LDPE bags with aluminum foil;

[0094] The solution product from batch 034101 was used for preliminary stability experiments.

[0095] The photodestructive study was designed to evaluate any potential effects of light exposure on ethanolic solutions of AST-3424 drug substance. The ethanolic solutions of AST-3424 drug substance were transferred to clear glass vials and exposed to 1.08x10 6 The samples were irradiated with sunlight (visible and UV) for 1 hour (i.e. 10 days at 4500 lx) (25°C + 4500 ± 500 Lx). A control sample (25°C + 4500 ± 500 Lx + covered) was prepared in a separate transparent glass vial placed in an aluminum foil bag.

[0096] In addition to the test samples and control samples, two other positive control samples were prepared in separate transparent vials and stored in a dark room at 25°C and 40°C (25°C + natural light, 40°C + natural light). The purpose of storing in a dark room at 25°C and 40°C was to observe the temperature effect behind the photodestructive group.

[0097] Samples were tested on days 0, 5, and 10 for appearance, assay, related substances, chemical purity, and enantiomeric excess.

[0098] The samples were placed under corresponding storage conditions to study the data changes of corresponding indicators such as content, chemical purity, enantiomeric excess at different time points. The research results are shown in Table 3 below.

[0099] Table 3: Data on the content (mass percentage of AST-3424 in the solution), chemical purity, enantiomeric excess, and other indicators of the solution product of batch 034101 at different storage temperatures and whether it is protected from light at different time points

[0100]

[0101] 40℃ + natural light, placed in a laboratory non-direct sunlight natural light environment (dark room) at a temperature of 40℃.

[0102] 25℃ + natural light, placed in a laboratory non-direct sunlight natural light environment (dark room) at a temperature of 25℃.

[0103] 25℃+4500±500Lx, place in a drug stability test chamber at 25℃ and set the light intensity to 4500±500Lx.

[0104] 25℃+4500±500Lx+cover, place in a drug stability test box at 25℃, set the light intensity to 4500±500Lx, and wrap the sample completely with aluminum foil.

[0105] Analyzing the experimental data, we can find that:

[0106] Starting from day 5, a color change from light yellow to light brown was observed only in the test samples exposed to 4500 lx. In other test items including assay, chemical purity, and enantiomeric excess, no differences were found between the 4500 lx ± 500 lx samples and the 25°C darkroom control samples.

[0107] Increased impurities (decreased chemical purity) were observed in both the 4500±500 Lx and 40&25°C darkroom samples. These impurities were caused by the increased temperature during the photodestructive studies.

[0108] Overall, exposure to light has little effect on assay, chemical purity, individual and total impurities, and enantiomeric excess. It is recommended to store the ethanolic solution of AST-3424 drug substance in the dark to maintain the stability of its physicochemical properties (such as color).

[0109] Preliminary stability test conclusions:

[0110] The ethanol solution of AST-3424 raw material showed no significant changes in 5 days and 10 days when stored at 25°C under light and dark conditions, but there were significant changes in the sample stored at 40°C for 10 days.

[0111] Preliminary experiments revealed that temperature is a significant factor affecting stability, with low temperatures favoring stability during storage. Light exposure does have an impact, but the effect is less significant than temperature. Therefore, long-term stability studies should test the stability of solution products under different low-temperature conditions in a dark environment.

[0112] 2.3 Long-term stability study at different low-temperature storage temperatures

[0113] Three batches of long-term stability experiments at -20±5°C and 5±3°C and accelerated stability experiments at 25±2°C, 60±5% RH were conducted under light-proof conditions.

[0114] For samples used for stability studies, the inner packaging was HDPE bottles with screw caps, and the outer packaging was LDPE bags with drawstrings placed in heat-sealed aluminum foil bags.

[0115] The water content (mass percentage), content, purity (chemical purity), and enantiomeric excess (ee%) were measured at 0, 1, 2, 3, 6, 9, 12, 18, 24, 36, and 42 months, respectively. The specific results are shown in Tables 4, 5, and 6 below. Samples from batches 024101, 034101, and 044101 were used in this experiment.

[0116] Table 4: Data from the long-term stability test at -20±5°C and 5±3°C and the accelerated stability test at 25±2°C, 60±5% RH for batch 024101

[0117]

[0118] Table 5: Data from the long-term stability test at -20±5°C and 5±3°C and the accelerated stability test at 25±2°C, 60±5% RH for batch 034101

[0119]

[0120] Table 6: Data from the long-term stability test at -20±5°C and 5±3°C and the accelerated stability test at 25±2°C, 60±5% RH for batch 044101

[0121]

[0122] *Indicates that the indicator no longer meets the quality standards.

[0123] -----Indicates that the sample has failed or the batch of samples will not be tested subsequently.

[0124] Analyzing the experimental data, we can find that:

[0125] In all test items, no significant changes were observed in the 42-month stability data of samples stored at -20±5°C. A small amount of impurities was observed in the 18-month stability data, and the impurity content was within 0.26%. The total impurities increased slightly but were still within the standard limit of 2% (i.e., chemical purity was greater than or equal to 98%).

[0126] Small amounts of impurities were observed in the 12-month stability data for samples stored at 5±3°C. Impurity levels in individual samples were within 0.44%. At the 18- and 24-month time points, total impurity levels exceeded 2.0%, which no longer met the quality standard. With the exception of impurity (related substance) data, all other test items, including appearance, water content, assay, chemical purity, and enantiomeric excess, remained unchanged throughout the 24-month stability study.

[0127] Under accelerated conditions at 25±2°C, chemical purity decreased significantly and impurity levels increased significantly, both in terms of number of individual impurities and the concentration of certain impurities. Total impurities exceeded the 2% standard limit after the second month. At the six-month time point, total impurities continued to increase, reaching %. However, enantiomeric excess (ee%) remained unchanged.

[0128] Overall, ethanol solutions of AST-3424 API (with a content range of 35.4%-39.59%) were stable for at least 42 months at -20°C.

[0129] At 25°C, AST-3424 degraded rapidly and the purity was less than 98% after 2 months.

[0130] 2.4 Compatibility of the API with the primary container closure system

[0131] Upright and inverted orientation studies simulate potential contact between the drug substance and the primary container closure system during transportation. Three ethanolic solutions of AST-3424 drug substance stored in HDPE bottles with HDPE screw caps were inverted and stored at -20±5°C and 5±3°C for one month. Appearance, moisture content, assay, chemical purity, related substances, and enantiomeric excess were measured at -20±5°C and 5±3°C for one month, respectively. Detailed experimental data are shown in Table 7.

[0132] Table 7: Long-term stability test data of different batches at -20±5℃ and 5±3℃ inverted conditions

[0133]

[0134] Analyzing the experimental data, we can find that:

[0135] The test results did not change.

[0136] Based on the results, HDPE bottles are considered suitable as the inner packaging container closure system for AST-3424 API ethanol solution at 5±3°C and -20±5°C.

Claims

1. A stable AST-3424 bulk drug product, which is an ethanol solution of AST-3424, wherein the mass percentage of AST-3424 in the solution is 25-70%, preferably 25-45%, and more preferably 30-40%.

2. The stable AST-3424 bulk drug product according to claim 1, wherein The HPLC chemical purity test result of AST-3424 is greater than or equal to 98.0%, and the HPLC chemical content test result of the isomer is less than or equal to 2.0%.

3. The stable AST-3424 API product according to claim 1 has a shelf life of greater than or equal to 24 months at -20±5°C in the dark.

4. The stable AST-3424 API product according to claim 1 has a shelf life of greater than or equal to 36 months at -20±5°C in the dark.

5. The stable AST-3424 API product according to claim 1 has a shelf life of greater than or equal to 42 months at -20±5°C in the dark.

6. The stable AST-3424 bulk drug product according to claim 1, wherein The residual silver mass percentage is less than or equal to 15 parts per million.

7. The stable AST-3424 bulk drug product according to claim 1, wherein the mass percentage of AST-3424 in the solution is 35.4%-39.59%.

8. The stable AST-3424 bulk drug product according to claim 1, wherein the residual solvent mass limit requirement in the solution is: Acetone ≤ 5000ppm, Ethyl acetate ≤ 5000ppm, Tetrahydrofuran ≤ 720ppm, Triethylamine ≤5000ppm, Methanol ≤ 3000ppm, n-heptane ≤ 5000ppm, Dichloromethane ≤ 600ppm.

9. A packaging unit comprising a container and the stabilized AST-3424 API product according to any one of claims 1 to 8 contained in the container, wherein the container comprises a container body for containing the API and a sealing structure for sealing the container body, wherein both the container body and the sealing structure are made of pharmaceutical-grade high-density polyethylene.

10. The packaging unit according to claim 8, further comprising a light-shielding structure wrapping the container. The packaging unit according to claim 9 , wherein the light-shielding structure is an aluminum foil bag.

12. A method for preparing the stable AST-3424 bulk drug product according to any one of claims 1 to 6, comprising mixing the isolated and purified oily AST-3424 product with anhydrous ethanol at a temperature not exceeding 30° C. and then distilling under reduced pressure until the mass percentage of AST-3424 reaches a predetermined value.

13. The preparation method according to claim 12, wherein the mixture is mixed with anhydrous ethanol and then distilled under reduced pressure three times, wherein the first two operations are concentrated under reduced pressure until no fraction is left, and the third operation is distilled under reduced pressure until the mass percentage of AST-3424 reaches a predetermined value.

14. The preparation method according to any one of claims 12 to 14, wherein: The pressure of vacuum distillation is gauge pressure P≤-0.08MPa.

15. The method for storing the stable AST-3424 bulk drug product according to any one of claims 1 to 8, characterized in that: It is stored at -20±5℃.

16. The method for storing the stable AST-3424 bulk drug product according to any one of claims 1 to 8, wherein: It is stored at -20±5°C in a dark environment.

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