Method for detecting related substances of crisaborole intermediate 4-(4-bromo-3-formylphenoxy) benzonitrile

Abstract

The invention discloses a method for detecting related substances of a crisaborole intermediate 4-(4-bromine-3-formylphenoxy) benzonitrile. According to the method, separation and detection are carried out by adopting a high performance liquid chromatography method, taking a phenyl column as a chromatographic column, taking a certain amount of an acidic solution and an organic phase as mobile phases and adopting a gradient elution mode.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical drug analysis, and in particular to an analytical method for analyzing and determining a crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile and related impurities thereof by using liquid chromatography. Background Art

[0002] 4-(4-Bromo-3-formyl-phenoxy)benzonitrile, also known as 4-(4-Bromo-3-formyl-phenoxy)-benzonitrile in English, has a molecular formula of C14H8BrNO2 and a molecular weight of 302.12.

[0003]

[0004] Crisaborol was originally developed by Anacor Pharmaceuticals, which was acquired by Pfizer in May 2016. In December of the same year, the US FDA approved crisaborol ointment (2% or 5%) for the topical treatment of mild to moderate atopic dermatitis in patients aged two years and older. It is marketed under the trade name Eucrisa. As a nonsteroidal topical medication, crisaborol is indicated for the treatment of mild to moderate atopic dermatitis in adults and children, alleviating inflammation and thereby alleviating symptoms.

[0005] During the synthesis of 4-(4-bromo-3-formylphenoxy)benzonitrile, if other impurities cannot be completely removed, they will be introduced into the synthesis of crisaborole, which will affect the purity and quality of the drug. Therefore, separation of 4-(4-bromo-3-formylphenoxy)benzonitrile and other related impurities is achieved to ensure the quality control of crisaborole during the synthesis process. Summary of the Invention

[0006] The present invention provides a method for analyzing related substances of a crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile, thereby enabling rapid, effective and accurate monitoring of the purity of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile related substances, thereby achieving quality control of the final product raw material drug.

[0007] The present invention proposes a method for analyzing related substances of a crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile, which adopts high performance liquid chromatography, uses a phenyl column as a chromatographic column, uses a certain amount of acidic solution as mobile phase A and an organic phase as mobile phase B, and performs gradient elution.

[0008] The present invention provides a method for analyzing related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile, wherein the gradient elution procedure is:

[0009] Preferably, the certain amount of acidic solution is 0.1% trifluoroacetic acid solution.

[0010] Preferably, the organic phase is acetonitrile.

[0011] Preferably, the chromatographic column provided is Shim-pack Scepter PFPP-120 (4.6 mm×250 mm, 5 μm).

[0012] The separation and determination method of the present invention can be achieved by the following method: 1) Take an appropriate amount of 4-(4-bromo-3-formylphenoxy)benzonitrile sample and dissolve it in diluent to prepare a sample solution containing 0.2 mg of 4-(4-bromo-3-formylphenoxy)benzonitrile per 1 ml; 2) Set the mobile phase flow rate to 0.5-1.5 mL / min, preferably 1.0 mL / min, the detection wavelength to 220-240 nm, with the optimal detection wavelength being 226 nm, and the column oven temperature to 20-40°C, with the optimal column oven temperature being 30°C. 3) Take 20 μl of the sample solution from 1) above and inject it into a liquid chromatograph to separate and determine 4-(4-bromo-3-formylphenoxy)benzonitrile and related substances. High-performance liquid chromatograph: Agilent 1260 InfinityII; Chromatographic column: Shim-pack Scepter PFPP-120 (4.6 mm × 250 mm, 5 μm); Mobile phase A: 0.1% phosphoric acid solution (pipette 1 ml of phosphoric acid into 1000 ml of pure water, shake well, filter, and sonicate); Mobile phase B: acetonitrile; Elution was performed according to the following gradient:

[0013] Flow rate: 1.0 mL / min; Column temperature: 30°C; Detection wavelength: 226nm; Injection volume: 20 μl; The invention uses a Shim-pack Scepter PFPP-120 (250×4.6 mm, 5μm) chromatographic column to effectively separate 4-(4-bromo-3-formylphenoxy)benzonitrile and its related impurities, thereby improving the yield and purity of the product and ensuring the controllable quality of 4-(4-bromo-3-formylphenoxy)benzonitrile. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the blank solvent HPLC chart of 4-(4-bromo-3-formylphenoxy)benzonitrile in Example 1.

[0015] Figure 2 This is the HPLC chart of the 4-(4-bromo-3-formylphenoxy)benzonitrile intermediate and its related impurities in Example 1. DETAILED DESCRIPTION The following examples are provided to further understand the present invention, but are not intended to limit the scope of this invention.

[0017] Example 1 Instruments and conditions High-performance liquid chromatograph: Agilent 1260 InfinityII; Chromatographic column: Shim-pack Scepter PFPP-120 (4.6 mm × 250 mm, 5 μm); Mobile phase A: 0.1% phosphoric acid solution (pipette 1 ml of phosphoric acid into 1000 ml of pure water, shake well, filter, and sonicate); Mobile phase B: acetonitrile; Elution was performed according to the following gradient:

[0018] Flow rate: 1.0 mL / min; Column temperature: 30°C; Detection wavelength: 226nm; Injection volume: 20 μl; The HPLC detection steps for related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile are as follows: Take an appropriate amount of 4-(4-bromo-3-formylphenoxy)benzonitrile and its impurity reference substances, dissolve the sample in a diluent, and prepare a sample solution containing 0.2 mg / mL of 4-(4-bromo-3-formylphenoxy)benzonitrile and approximately 2 µg / mL of its impurities.

[0019] Take 20µl of the above solution and inject it into the liquid chromatograph to record the chromatogram.

[0020] Specificity test results:

[0021] Repeatability test results:

[0022] In summary, the present invention can separate 4-(4-bromo-3-formylphenoxy)benzonitrile from its impurities and can accurately perform quantitative detection, thereby effectively controlling the product quality of crisaborole.

Claims

1. A method for detecting related substances of a crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile, using high performance liquid chromatography, a phenyl column, a certain amount of acidic solution and an organic phase as mobile phases, and gradient elution.

2. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile as claimed in claim 1, the organic phase is selected from one of the following compounds: methanol, acetonitrile.

3. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile as claimed in claim 1, a certain amount of acidic solution is selected from one of the following inorganic salts: 0.05% trifluoroacetic acid solution, 0.1% trifluoroacetic acid solution, 0.2% trifluoroacetic acid solution.

4. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile as claimed in claim 1, the gradient process is a gradient elution of:

5. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile as claimed in claim 1, the chromatographic column preferably has a length of 254 mm, a diameter of 4.6 mm, and a filler particle size of 5 µm.

6. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile according to claims 1 and 3, the certain amount of acidic solution is preferably a 0.1% trifluoroacetic acid solution.

7. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile according to claims 2 and 4, the organic phase is preferably acetonitrile.

8. According to claim 1, the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile comprises the following steps: ① setting the flow rate to 0.5-1.5 ml / min; ② setting the detection wavelength to 210-240 nm; ③ setting the column temperature to 20-40 ° C; ④ setting the injection volume to 10-50 µl.

9. According to the method for analyzing and detecting related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile as claimed in claim 8, the chromatographic conditions are as follows: ① the flow rate is preferably 1.0 ml / min; ② the wavelength is preferably 226 nm; ③ the column temperature is preferably 30°C; ④ the injection volume is preferably 20 µl.

10. The method for analyzing related substances of the crisaborole intermediate 4-(4-bromo-3-formylphenoxy)benzonitrile according to claim 1, wherein the related substance impurities are:

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