Fluorohydrocortisone acetate impurity as well as preparation method and application thereof

Abstract

The invention discloses a fluorohydrocortisone acetate impurity as well as a preparation method and application thereof, and belongs to the technical field of medicine synthesis. The invention provides a synthesis method of a fluorohydrocortisone acetate impurity, which comprises the following steps: oxidizing a key intermediate 9beta, 11beta-epoxy-17alpha-hydroxypregna-4-ene-3, 20-dione-21-acetate of fluorohydrocortisone acetate serving as a raw material to obtain an impurity II, carrying out ring-opening reaction on the impurity II and a fluorinating reagent to obtain an impurity III, and purifying the impurity III to obtain the fluorohydrocortisone acetate impurity. The purity of the prepared impurities II and III is up to 96.0% or above, and the impurity II and the impurity III of the fluorohydrocortisone acetate can be used as standard substances for monitoring the impurity content of the fluorohydrocortisone acetate and have high application value.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical synthesis technology, and more specifically, relates to fluhydrocortisone acetate impurities, their preparation methods, and applications. Background Technology

[0002] Fludrocortisone acetate, also known as fludrocortisone acetate, 9α-fluorocortisol acetate, 9α-fluorohydrocortisone acetate, etc., has the chemical name 11β,17α,21-trihydroxy-9α-fluoropregn-4-ene-3,20-dione-21-acetate. It is a corticosteroid with strong mineralocorticoid activity, primarily used for the replacement therapy of adrenal insufficiency. It is mainly used to treat skin diseases such as allergic dermatitis, contact dermatitis, seborrheic dermatitis, and eczema. Commercially available dosage forms include tablets, ointments, and solutions.

[0003] All publicly reported synthetic methods for fludrocortisone acetate use 9β,11β-epoxy-17α-hydroxypregn-4-ene-3,20-dione-21-acetate (compound I) as a key intermediate, which is obtained through fluorination ring-opening and hydrolysis. For the safe use of fludrocortisone acetate, quality control, especially the control of impurities, is crucial to the safety and efficacy of the drug. Therefore, providing methods for preparing impurities in fludrocortisone acetate provides qualified, inexpensive, and readily available reference standards for the quality control of fludrocortisone acetate raw materials and formulations, offering important guidance for safe medication use.

[0004] This application provides a method for synthesizing impurities in fludrocortisone acetate and its detection in fludrocortisone acetate raw materials and formulations, which has not been reported before. Although the 2025 edition of the Chinese Pharmacopoeia controls the impurity limits for fludrocortisone acetate to no more than 2.0%, a slow increasing trend of some impurities has been observed during the industrial production and stability testing of fludrocortisone acetate. There is an urgent need in the field to identify the structure of this unknown impurity and develop effective monitoring methods to optimize processes, stabilize product quality, and provide a basis for improving quality standards. Summary of the Invention

[0005] Since there are no reported synthetic studies on the potential impurities generated during the existing synthesis of fludrocortisone acetate, making it impossible to effectively monitor and evaluate the quality of fludrocortisone acetate, the first technical problem to be solved in this application is to provide two types of fludrocortisone acetate impurities. The second technical problem to be solved in this application is to provide methods for preparing the aforementioned two types of fludrocortisone acetate impurities. The final technical problem to be solved in this application is to provide specific applications for the aforementioned two types of fludrocortisone acetate impurities.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a fludrocortisone acetate impurity, wherein the fludrocortisone acetate impurity is impurity II or impurity III, and the steps of the preparation method are as follows:

[0008]

[0009] Step S1: Take compound I as raw material, dissolve it in a protic solvent, add an oxidant to react and obtain the impurity II. The specific name of compound I is 9β,11β-epoxy-17α-hydroxypregn-4-ene-3,20-dione-21-acetate.

[0010] Step S2: Take the impurity II as a raw material, dissolve it in an aprotic solvent, and carry out a ring-opening reaction with a fluorinating reagent to obtain the impurity III.

[0011] In some embodiments, the oxidant is any one of tetrachlorobenzoquinone, 2,3-dichloro-5,6-dicyanobenzoquinone, and 2,5-dichloro-1,4-benzoquinone.

[0012] In some embodiments, the proton solvent is any one of ethanol, isopropanol, tert-butanol, and sec-butanol.

[0013] In some embodiments, in step S1, the molar ratio of compound I to oxidant is 1:1.2~2.0.

[0014] In some embodiments, the fluorinating agent is any one of 50-70% pyridine hydrogen fluoride solution, 45-55% dimethylformamide hydrogen fluoride solution, 70% pyridine hydrofluoride, and triethylamine trihydrofluoride.

[0015] In some embodiments, in step S2, the molar ratio of impurity II to fluorinating reagent is 1:3.0~5.0.

[0016] In some embodiments, the reaction temperature of the ring-opening reaction is -10 to 20°C.

[0017] A fludrocortisone acetate impurity, wherein the fludrocortisone acetate impurity is impurity II or impurity III, and its structure is shown below:

[0018] .

[0019] The application of the aforementioned fludrocortisone acetate impurity in the detection of fludrocortisone acetate raw material or fludrocortisone acetate preparation.

[0020] In some embodiments, the fludrocortisone acetate formulation is fludrocortisone acetate cream, fludrocortisone acetate tablets, or fludrocortisone acetate solution.

[0021] Compared with the prior art, the present invention has at least the following application value:

[0022] (1) This invention discloses for the first time a method for preparing fluhydrocortisone acetate impurity, involving an impurity synthesis route with readily available raw materials, simple operation method, no need to enrich and purify from production process by-products or mother liquor, a directional reaction process that is safe, controllable, efficient and convenient, and the product purity exceeds 96.0%, meeting the quality requirements of impurity reference standards.

[0023] (2) The impurities synthesized in this invention can provide impurity reference standards for the quality research of fludrocortisone acetate, laying a solid foundation for the effective control of the quality of fludrocortisone acetate-related drugs. At the same time, it provides a technical basis for improving the national quality standards of fludrocortisone acetate. Attached Figure Description

[0024] Figure 1 Fluhydrocortisone acetate impurity II 1 H-NMR spectrum;

[0025] Figure 2 Fluhydrocortisone acetate impurity III 1 H-NMR spectrum;

[0026] Figure 3 This is the mass spectrum of fluhydrocortisone acetate impurity II;

[0027] Figure 4 The mass spectrum of fluhydrocortisone acetate impurity III;

[0028] Figure 5 System suitability chromatograms for fluhydrocortisone acetate and impurities II and III;

[0029] Figure 6 This is a batch chromatogram of fludrocortisone acetate produced in the industrial sector. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention and should be understood as being for illustrative purposes only and not for limiting the scope of the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0031] Example 1

[0032] A method for preparing a fludrocortisone acetate impurity includes the following steps:

[0033] 1) In a 250 ml single-necked flask, add 7.0 g (17.4 mmol) of compound I, 105 ml (15 v / w) of tert-butanol, and 5.56 g (22.62 mmol) of tetrachlorobenzoquinone, and reflux for 1 h. Filter, add 250 ml of water, extract the product with 500 ml of dichloromethane, wash the organic phase with 250 ml of saturated sodium bicarbonate solution, filter, separate the layers, wash the organic phase once with 250 ml of water, concentrate the organic phase to obtain a viscous substance, recrystallize with 2 ml of ethyl acetate to give 3.2 g of impurity II, yield 45.7%, purity 97.5%.

[0034] 2) In a 10 ml single-necked flask, add 1 g (7.93 mmol) of impurity II and 5 ml (5 v / w) of dichloromethane. Stir magnetically and cool to 0-10 °C. Add a pyridine hydrogen fluoride solution (approximately 65%, 0.9 g, approximately 23.8 mmol), and react for 4 h. Dilute with 15 ml of dichloromethane, then adjust the pH to 5-7 with 10% potassium phosphate solution. Wash the organic phase once with water, concentrate to approximately 2 ml, stir in an ice-water bath for 1 h, filter, and dry to obtain 519 mg of impurity III, with a yield of 51.9% and a purity of 96.4%.

[0035] like Figure 1 As shown, the 1H NMR spectrum (1H-NMR instrument: BRUKER AV-400 NMR spectrometer) of the fluhydrocortisone acetate impurity II obtained in Example 1 was analyzed, and the 1H spectrum was resolved as follows: 1 H-NMR (400MHz, CDCl3): δ5.78(s,1H), 5.14(d,J=17.6Hz,1H), 4.75(d,J=17.6Hz,1H), 3.46(s,1H), 2.78-2.70(m,1H), 2.60(s,1H), 2. 50(m,3H), 2.40-2.20(m,4H), 2.15(s,3H), 2.10-2.00(s,1H), 1.90(m,2H), 1.75(m,1H), 1.65-1.45(m,3H), 1.42(s,3H), 1.30(m,2H). The type and number of protons in the test sample were found to be consistent with the hydrogen atom characteristics in the structure of fluhydrocortisone acetate impurity II.

[0036] like Figure 3 As shown, the mass spectrometry of fludrocortisone acetate impurity II obtained according to Example 1 shows that its molecular weight is 401.3 (M+H). The result is consistent with the structural characteristics of fludrocortisone acetate impurity II.

[0037] like Figure 2 As shown, the 1H NMR spectrum (1H-NMR instrument: BRUKER AV-400 NMR spectrometer) of the fluhydrocortisone acetate impurity III obtained in Example 1 was analyzed, and the 1H spectrum was resolved as follows:1 H-NMR (400MHz, DMSO-d6): δ6.27(dd,J=2.8,10Hz,1H), 6.00(d,J=11.2Hz,1H), 5.69(s, 1H), 5.54(s,1H), 5.26(d,J=3.6Hz,1H), 5.06(d,J=17.6Hz,1H), 4.81(d,J=17.6Hz,1H), 4.14(broad peak, 1H), 2.89 (m, 1H), 2.62(m, 2H), 2.42-2.15(m, 4H), 2.10(s, 3H), 2.06(m, 1H), 1.80(m, 1H), 1.56-1.42(m, 3H), 1.39(s, 3H), 0.81(s, 3H). The type and number of protons in the sample were consistent with the hydrogen atom characteristics in the structure of fluhydrocortisone acetate impurity III.

[0038] like Figure 4 As shown, the mass spectrometry of fludrocortisone acetate impurity III obtained according to Example 1 shows that its molecular weight is 421.3 (M+H). The result is consistent with the structural characteristics of fludrocortisone acetate impurity III.

[0039] Example 2

[0040] A method for preparing a fludrocortisone acetate impurity includes the following steps:

[0041] 1) In a 250 ml single-necked flask, add 7.0 g (17.4 mmol) of compound I, 105 ml (15 v / w) of sec-butanol, and 7.9 g (34.8 mmol) of 2,3-dichloro-5,6-dicyanobenzoquinone, and reflux for 3 h. Filter, add 250 ml of water, extract the product with 500 ml of dichloromethane, wash the organic phase with 250 ml of saturated sodium bicarbonate solution, filter, separate the layers, wash the organic phase once with 250 ml of water, concentrate the organic phase to obtain a viscous substance, recrystallize with 3 ml of ethyl acetate to give 2.2 g of impurity II, yield 31.4%, purity 96.1%.

[0042] 2) In a 10 ml single-necked flask, add 1 g (7.93 mmol) of impurity II and 5 ml (5 v / w) of dimethylformamide. Stir magnetically and cool to -10 to 0 °C. Add a 50% dimethylformamide solution (approximately 1.5 g, approximately 39.6 mmol) and react for 4 h. Dilute with 15 ml of dichloromethane, then adjust the pH to 5-7 with 10% potassium phosphate solution. Wash the organic phase once with water, concentrate to approximately 2 ml, stir in an ice-water bath for 1 h, filter, and dry to obtain 424 mg of impurity III, yield 42.4%, purity 96.2%.

[0043] Example 3

[0044] A method for preparing a fludrocortisone acetate impurity includes the following steps:

[0045] 1) In a 250 ml single-necked flask, add 7.0 g (17.4 mmol) of compound I, 70 ml (10 v / w) of isopropanol, and 6.16 g (34.8 mmol) of 2,5-dichloro-1,4-benzoquinone, and reflux for 18 h. Filter, add 250 ml of water, extract the product with 500 ml of dichloromethane, wash the organic phase with 250 ml of saturated sodium bicarbonate solution, filter, separate the layers, wash the organic phase once with 250 ml of water, concentrate the organic phase to obtain a viscous substance, recrystallize with 2 ml of ethyl acetate to give 2.4 g of impurity II, yield 34.3%, purity 96.5%.

[0046] 2) In a 10 ml single-necked flask, add 1 g (7.93 mmol) of impurity II and 5 ml (5 v / w) of dichloromethane. Stir magnetically and cool to 0-10 °C. Add pyridine hydrogen fluoride solution (approximately 50%, 1.5 g, approximately 39.6 mmol), and react for 12 h. Dilute with 15 ml of dichloromethane, then adjust the pH to 5-7 with 10% potassium phosphate solution. Wash the organic phase once with water, concentrate to approximately 2 ml, stir in an ice-water bath for 3 h, filter, and dry to obtain 321 mg of impurity III, yield 32.1%, purity 96.9%.

[0047] Example 4

[0048] A method for preparing a fludrocortisone acetate impurity includes the following steps:

[0049] 1) In a 250 ml single-necked flask, add 7.0 g (17.4 mmol) of compound I, 70 ml (10 v / w) of ethanol, and 5.56 g (22.62 mmol) of tetrachlorobenzoquinone, and reflux for 24 h. Filter, quench with 250 ml of water, extract the product with 500 ml of dichloromethane, wash the organic phase with 250 ml of saturated sodium bicarbonate solution, filter, separate, wash the organic phase once with 250 ml of water, concentrate the organic phase to obtain a viscous substance, recrystallize with 2 ml of ethyl acetate to give 3.6 g of impurity II, yield 51.4%, purity 97.8%.

[0050] 2) In a 10 ml single-necked flask, add 1 g (7.93 mmol) of impurity II and 10 ml (10 v / w) of chloroform, stir magnetically, cool to 10-20 °C, add 0.65 g (approximately 23.8 mmol) of 70% pyridine hydrofluoric acid, and react for 3 h. Dilute with 15 ml of dichloromethane, adjust the pH to 5-7 with 10% potassium phosphate solution, wash the organic phase once with water, concentrate to approximately 2 ml, stir in an ice-water bath for 1 h, filter, and dry to obtain 372 mg of impurity III, yield 37.2%, purity 96.2%.

[0051] Example 5

[0052] A method for preparing a fludrocortisone acetate impurity includes the following steps:

[0053] 1) In a 250 ml single-necked flask, add 7.0 g (17.4 mmol) of compound I, 70 ml (10 v / w) of ethanol, and 6.16 g (34.8 mmol) of 2,5-dichloro-1,4-benzoquinone, and reflux for 2 h. Filter, add 250 ml of water, extract the product with 500 ml of dichloromethane, wash the organic phase with 250 ml of saturated sodium bicarbonate solution, filter, separate the layers, wash the organic phase once with 250 ml of water, concentrate the organic phase to obtain a viscous substance, recrystallize with 2 ml of ethyl acetate to give 2.9 g of impurity II, yield 41.4%, purity 97.0%.

[0054] 2) In a 10 ml single-necked flask, add 1 g (7.93 mmol) of impurity II and 15 ml (15 v / w) of dichloromethane, stir magnetically, cool to 10-20 °C, add 1.28 g (7.93 mmol) of triethylamine trihydrofluoride, and react for 6 h. Adjust the pH to 5-7 with 10% potassium phosphate solution, wash the organic phase once with water, concentrate to about 2 ml, stir in an ice-water bath for 1 h, filter, and dry to obtain 400 mg of impurity III, yield 40.0%, purity 96.8%.

[0055] The following experimental examples illustrate the beneficial effects of the present invention:

[0056] Example 6

[0057] Application of Impurity II and Impurity III in the Quality Study of Fludrocortisone Acetate

[0058] HPLC: Liquid chromatograph: Shimadzu LC-20AT; Column: Agela Venusil ASB-C18, 4.6 × 250 mm, 5 μm column. Detection wavelength: 245 nm, flow rate: 1.0 mL / min, column temperature: 38 °C. Injection volume: 5 μL. Elution was performed using methanol-water (60:40) as the mobile phase.

[0059] Accurately weigh approximately 10 mg each of fludrocortisone acetate impurity II and fludrocortisone acetate impurity III, place them in 100 ml volumetric flasks, and dissolve them separately in acetonitrile-0.01 mol / L ammonium formate solution by sonication. Prepare impurity stock solutions by shaking. Accurately weigh approximately 20 mg of fludrocortisone acetate, place it in a 10 ml volumetric flask, add 1 ml of the impurity stock solution, add solvent, sonicate to dissolve, and dilute to the mark. Prepare system suitability solution. Accurately measure 5 μl of the system suitability solution and inject it into the liquid chromatograph. Record the chromatogram. Impurity III, fludrocortisone acetate, and impurity II should emerge sequentially. The theoretical plate number, calculated based on the fludrocortisone acetate peak, should not be less than 3000. The fludrocortisone acetate peak should be effectively separated from the peaks of impurities III and II, meeting the requirements of the Chinese Pharmacopoeia. Figure 5 ).

[0060] Example 7

[0061] The content of impurities II and III in batches of fludrocortisone acetate.

[0062] According to publicly reported methods for synthesizing fludrocortisone acetate, using 9β,11β-epoxy-17α-hydroxypregn-4-ene-3,20-dione-21-acetate (compound I) as a key intermediate, crude fludrocortisone acetate was obtained through fluorination ring-opening and hydrolysis. The contents of impurities II and III in the finished product are shown in Table 1 below:

[0063] Table 1 Content of Impurity II and Impurity III in the Finished Product

[0064]

[0065] The changes in the content of impurity II and impurity III in the destructive experiment of fludrocortisone acetate are shown in Table 2 below:

[0066] Table 2. Changes in the content of impurity II and impurity III during the destructive experiment.

[0067]

[0068] Data from multiple batches shows that impurities II and III were detected in both crude and finished fludrocortisone acetate, with some batches showing impurity III levels close to 0.10%. Figure 6 Although the levels are far below the limits set by the Chinese Pharmacopoeia, they are close to the 0.10% limit for unknown impurities. With future process optimization and quality improvement in fludrocortisone acetate, this impurity can be studied as a known impurity and controlled within the limits outlined in the ICH guidelines. Furthermore, destructive testing shows that impurity III in the finished fludrocortisone acetate product exhibits significant increases under light and alkali degradation; therefore, light protection is necessary during the storage of fludrocortisone acetate. This further illustrates the significance of determining the structure of this impurity.

[0069] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. The above description is illustrative only and not restrictive. Those skilled in the art will understand that many modifications, variations, or equivalents can be made without departing from the spirit and scope defined by the appended claims, and all such modifications, variations, or equivalents will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a fluhydrocortisone acetate impurity, characterized in that, The fluhydrocortisone acetate impurity is impurity II or impurity III, and the preparation method includes the following steps: ； Step S1: Take compound I as raw material, dissolve it in a protic solvent, add an oxidant to react and obtain the impurity II. The specific name of compound I is 9β,11β-epoxy-17α-hydroxypregn-4-ene-3,20-dione-21-acetate. Step S2: Take the impurity II as a raw material, dissolve it in an aprotic solvent, and carry out a ring-opening reaction with a fluorinating reagent to obtain the impurity III.

2. The preparation method according to claim 1, characterized in that, The oxidant is any one of tetrachlorobenzoquinone, 2,3-dichloro-5,6-dicyanobenzoquinone, and 2,5-dichloro-1,4-benzoquinone.

3. The preparation method according to claim 1, characterized in that, The proton solvent is any one of ethanol, isopropanol, tert-butanol, and sec-butanol.

4. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of compound I to oxidant is 1:1.2~2.

0.

5. The preparation method according to claim 1, characterized in that, The fluorinating agent is any one of 50-70% pyridine hydrogen fluoride solution, 45-55% dimethylformamide hydrogen fluoride solution, 70% pyridine hydrofluoric acid salt, or triethylamine trihydrofluoric acid salt.

6. The preparation method according to claim 1, characterized in that, In step S2, the molar ratio of impurity II to fluorinating reagent is 1:3.0~5.

0.

7. The preparation method according to claim 1, characterized in that, The reaction temperature for the ring-opening reaction is -10 to 20°C.

8. Fluorohydrocortisone acetate impurity prepared by the preparation method according to any one of claims 1-7.

9. The use of the fludrocortisone acetate impurity as described in claim 8 in the detection of fludrocortisone acetate raw material or fludrocortisone acetate preparation.

10. The application according to claim 9, characterized in that, The fludrocortisone acetate formulation is fludrocortisone acetate cream, fludrocortisone acetate tablets, or fludrocortisone acetate solution.

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