Method for detecting related substances in butylphthalide

Abstract

The invention provides a method for detecting related substances in butylphthalide, and relates to the technical field of chemical detection and analysis. The detection method is a high performance liquid chromatography, a gradient elution procedure is adopted for elution, and chromatographic conditions are as follows: a chromatographic column is Inertsil ODS-3 (4.6 * 250 mm, 5 [mu] m); the mobile phase A is methanol, and the mobile phase B is a phosphoric acid solution; the flow velocity of the mobile phase is 1.0 mL / min; the sample size is 10 [mu] L; the detection wavelength is 228 nm; the column temperature is 30 DEG C; the detection method is good in specificity, high in durability and system adaptability, accurate and reliable in detection result, capable of achieving separation and detection of eight related substances in butylphthalide and beneficial to effective control of butylphthalide medicine quality.

Description

Technical Field

[0001] The invention relates to the field of drug detection and analysis, and in particular to a method for detecting related substances in butylphthalide. Background Art

[0002] Butylphthalide is an oily liquid with a strong celery aroma. Its chemical name is racemic-3-n-butylphthalide, and its structural formula is as follows:

[0003]

[0004] Clinical research results show that butylphthalide can improve the central nervous system damage in patients with acute ischemic stroke and promote the improvement of neurological deficits. It is mainly used in the clinic to improve the neurological deficits in patients with acute ischemic stroke.

[0005] The study of related substances is one of the key projects in drug quality research, and its content directly affects the safety and effectiveness of drugs. The related substances of drugs mainly include process impurities introduced during the production process, such as starting materials and their impurities, intermediates or side reaction products, and degradation impurities generated during storage. According to the structural properties and main synthesis process of butylphthalide, there are many types of impurities that may exist in butylphthalide. The development of related substance detection methods that can detect more impurities and have better specificity, sensitivity and accuracy is of great significance to the quality control of butylphthalide and improving product safety and reliability.

[0006] There are a few existing documents that have studied the detection methods of butylphthalide-related substances. The national drug standard WS1-(X-124)-2005Z for butylphthalide discloses the detection method of butylphthalide content and related substances, using octadecylsilane bonded silica gel as filler, methanol-water (65:35) as mobile phase, detection wavelength of 280nm, and separation test solution containing butylphthalide and propylphthalide in methanol solution. This method cannot effectively detect degradation impurities, and can separate fewer impurities.

[0007] The document "Detection of impurities in butylphthalide raw materials by reversed-phase high performance liquid chromatography" (Li Qin et al. Journal of Pharmaceutical Analysis, 2020, 40(07): 1277-1283. DOI: 10.16155 / j.0254-1793.2020.07.16.) describes a reversed-phase high performance liquid chromatography method that can simultaneously detect impurities such as hydroxybutylphthalide and propylphthalide, but cannot detect alkenylphthalide impurities such as butylenephthalide. Patent CN106093238A discloses a method for butylphthalide and its related substances, which can separate 6 known impurities, namely dipotassium phthalate, intermediate I, intermediate II, propylphthalide, butylenephthalide, and dibutylphthalide. It cannot separate pentylphthalide and epoxide.

[0008] Therefore, developing a related substance detection method that can simultaneously detect impurities such as butylphthalide degradation impurities, butylphthalide analog impurities, and process intermediates is of great significance to improving the accuracy of quality research on butylphthalide products and enhancing product safety and reliability. Summary of the invention

[0009] In view of the existing literature reports, the purpose of the present invention is to establish a comprehensive, effective and stable analysis method for the related substances of butylphthalide raw materials and their preparations. The applicant has identified 8 major known impurities through a large number of experiments and traced the impurities to their sources, including impurities introduced from the reaction raw materials: phthalide, impurities introduced during the reaction: propylphthalide, sec-butylphthalide, pentylphthalide, and product degradation impurities: 2-(1-oxopentyl)-benzoic acid, propylenephthalide, butylphthalide, pentylphthalide, whose structural formula is as follows:

[0010]

[0011] The present invention is achieved in that a method for detecting related substances in butylphthalide is provided, the method comprising the following steps:

[0012] Step (1) Sample preparation:

[0013] Test solution: Take butylphthalide raw material or its preparation, dissolve it in methanol solution, and prepare a butylphthalide solution with a concentration of 1 mg / mL.

[0014] Reference substance stock solution: Weigh 5 mg each of phthalide, propylphthalide, 2-(1-oxopentyl)-benzoic acid, sec-butylphthalide, propylenephthalide, pentylphthalide, butylphthalide, and pentylphthalide impurities into a 50 mL volumetric flask, add methanol to dissolve and dilute to the scale, shake well, and use as the reference substance stock solution.

[0015] Test sample spike solution: weigh 10 mg of butylphthalide into a 10 mL volumetric flask, add 1 mL of reference stock solution, dilute to the mark with methanol, and shake well.

[0016] Step (2) Chromatographic conditions and injection procedure:

[0017] Take the butylphthalide test solution and the test sample spiked solution prepared in step (1), measure 10 μl of the butylphthalide test solution and the test sample spiked solution, respectively, inject them into the liquid chromatograph, perform gradient elution, and record the chromatogram; use reverse phase C 18The column temperature is set at 25°C to 35°C; methanol or methanol-water solution is used as mobile phase A, phosphoric acid-water solution (0.05%-0.15%) is used as mobile phase B, and gradient elution is performed; the flow rate is 0.5-1.5 mL / min; the detection wavelength is 226-230 nm; the eluent is composed of mobile phase A and mobile phase B, wherein the elution conditions are as follows:

[0018] Time (min) Mobile phase A (%) Mobile phase B (%) 0 50～55 50～45 35 50～55 50～45 40 65 35 65 65 35 80 80 20 85 80 20 86 50 50 96 50 50 .

[0019] Furthermore, the butylphthalide in step (1) is diluted with methanol.

[0020] Furthermore, the specifications of the chromatographic column are 4.6*250mm, 5μm.

[0021] Furthermore, the flow rate is 1.0 mL / min.

[0022] Furthermore, the detection wavelength is 228 nm.

[0023] Furthermore, the column temperature is 30°C.

[0024] Furthermore, the concentration of the mobile phase B phosphoric acid solution is 0.1%.

[0025] Furthermore, the initial ratio of the mobile phase in the gradient elution program is mobile phase A:mobile phase B=50%:50%.

[0026] Further, the gradient elution procedure is:

[0027]

[0028]

[0029] The method for detecting related substances in butylphthalide of the present invention can be used for quality control of butylphthalide raw materials and preparations thereof.

[0030] The present invention has the following beneficial effects:

[0031] The detection method for related substances in butylphthalide provided by the invention has good specificity, high precision and accuracy, and good durability. The peak shape of each peak in the chromatographic peak is good, and the separation between the impurity peak and the main peak and between the impurity peaks is greater than 1.5. The method is suitable for detecting 8 related substances in butylphthalide and can realize the quality monitoring of butylphthalide. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the ultraviolet wavelength scanning diagram of butylphthalide in Example 1.

[0033] Figure 2It is the chromatogram of the test solution in Example 1.

[0034] Figure 3 It is the chromatogram of the spiked test solution in Example 1.

[0035] Figure 4 It is the chromatogram of the spiked test solution at a detection wavelength of 226 nm in Example 2.

[0036] Figure 5 This is the chromatogram of the spiked test solution at a detection wavelength of 230 nm in Example 3

[0037] Figure 6 This is the chromatogram of the spiked test solution at a column temperature of 35°C in Example 4.

[0038] Figure 7 This is the chromatogram of the spiked test solution at a column temperature of 25°C in Example 5.

[0039] Figure 8 This is the chromatogram of the spiked test solution at a mobile phase flow rate of 1.2 mL / min in Example 6.

[0040] Fig. 9 This is the chromatogram of the spiked test solution at a mobile phase flow rate of 0.8 mL / min in Example 7.

[0041] Fig.10 This is the chromatogram of the spiked test solution when the initial ratio of the mobile phase is 45:55 in Example 8.

[0042] Fig.11 This is the chromatogram of the spiked test solution in Example 9 when the initial ratio of the mobile phase is 55:45.

[0043] Fig.12 This is the chromatogram of the spiked test solution when the phosphoric acid concentration of mobile phase B in Example 10 is 0.05%.

[0044] Fig.13 This is the chromatogram of the spiked test solution when the phosphoric acid concentration of mobile phase B in Example 11 is 0.15%.

[0045] Fig.14 This is the chromatogram of the spiked test solution in Example 1.

[0046] Fig.15 a is the chromatogram of the spiked test solution in Example 2; 15b is a partial enlarged view at the retention time of 44.503 min.

[0047] Fig.16 This is the chromatogram of the spiked test solution in Example 3. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with comparative examples and embodiments. The following embodiments are only for illustration and are not intended to limit the scope of protection of the present invention in any form.

[0049] Example 1

[0050] First, the ultraviolet wavelength of butylphthalide was scanned. The results are shown in Figure 1 .like Figure 1 As shown, butylphthalide has an optimal absorption peak at 228nm.

[0051] (1) Solution preparation

[0052] Test solution: accurately weigh 10 mg of butylphthalide (Zhejiang Huahai Pharmaceutical, batch number 5715-2501) and place it in a 10 mL volumetric flask, add methanol to dissolve and dilute to the mark, and shake well.

[0053] Spiked test solution: Accurately weigh appropriate amounts of the test sample butylphthalide, reference substances phthalide, propylphthalide, open-epoxide, sec-butylphthalide, propylenephthalide, pentylphthalide, butylphthalide, and pentylphthalide, dissolve in methanol and quantitatively dilute to a spiked test solution with a butylphthalide concentration of 1 mg / mL and a reference substance phthalide, propylphthalide, open-epoxide, sec-butylphthalide, propylenephthalide, pentylphthalide, butylphthalide, and pentylphthalide concentration of 0.01 mg / mL.

[0054] (2) Chromatographic conditions

[0055] Instrument: High performance liquid chromatograph, model: Agilent 126;

[0056] Chromatographic column: Inertsil ODS-3 (4.6*250mm, 5μm);

[0057] Flow rate: 1.0 mL / min;

[0058] Injection volume: 10 μL;

[0059] Detection wavelength: 228nm;

[0060] Column temperature: 30°C;

[0061] Mobile phase A: methanol;

[0062] Mobile phase B: 0.1% phosphoric acid solution.

[0063] Gradient elution program:

[0064] Time (min) Mobile phase A (%) Mobile phase B (%) 0 50 50 35 50 50 40 65 35 65 65 35 80 80 20 85 80 20 86 50 50 96 50 50 .

[0065] Take 10 μL of the test solution and spiked test solution respectively, inject them into the liquid chromatograph, detect according to the chromatographic conditions, and record the chromatogram and related data.

[0066] Example 1 Test solution chromatogram Figure 2 .like Figure 2 As shown, the sample had a high purity, and only phthalide was detected at a retention time of 6.637 min. Other related substances may be produced in the process or in the later drug degradation process.

[0067] Example 1: Chromatogram of the spiked test solution Figure 3 .Depend on Figure 3 It can be seen that the substances and their corresponding retention times are as follows: phthalide (retention time 6.670min), propylphthalide (retention time 33.497min), epoxide (retention time 36.093min), sec-butylphthalide (retention time 44.830min), butylphthalide (retention time 47.683min), propylenephthalide (retention time 49.110min), pentylphthalide (retention time 61.870min), butylphthalide (retention time 63.413min), pentylphthalide (retention time 79.920min). The separation data of the relevant substances in the spiked test solution are shown in Table 1, indicating that butylphthalide is well separated from the relevant substances.

[0068] Table 1 Separation data of related substances in spiked test solution in Example 1

[0069] name Retention time / min Peak area Theoretical plates Separation Phthalide 6.670 9433561 11346 0.000 Propylphthalide 33.497 7245733 15372 40.306 Epoxide 36.093 4602173 14573 2.281 Sec-Butylphthalide 44.830 5719796 73266 9.402 Butylphthalide 47.683 702860825 126385 4.760 Acrylphthalide 49.110 7002448 112891 2.545 Pentylphthalide 61.870 5874582 70427 16.820 Butylphthalide 63.413 14061103 66047 1.608 Amylphthalide 79.920 5883967 317398 21.238

[0070] Table 2 Results of verification parameters for quantitative analysis of related substances in butylphthalide

[0071] name Detection limit (%) Limit of quantitation (%) Phthalide 0.002 0.005 Propylphthalide 0.002 0.007 Epoxide 0.003 0.009 Sec-Butylphthalide 0.005 0.016 Butylphthalide 0.003 0.010 Acrylphthalide 0.004 0.012 Pentylphthalide 0.003 0.010 Butylphthalide 0.004 0.012 Amylphthalide 0.004 0.012

[0072] Examples 2 to 11 Durability Verification

[0073] The detection wavelengths in Examples 2 to 3 were changed to 226 nm and 230 nm, respectively, and the other detection conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph to record the chromatogram.

[0074] Example 2: Chromatogram of the spiked test solution Figure 4 .like Figure 4As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 6.637min), propylphthalide (retention time 33.180min), epoxide (retention time 35.753min), sec-butylphthalide (retention time 44.683min), butylphthalide (retention time 47.507min), propylenephthalide (retention time 48.913min), pentylphthalide (retention time 61.550min), butylphthalide (retention time 63.080min), pentylphthalide (retention time 79.720min), indicating that butylphthalide is well separated from the eight related substances.

[0075] Example 3: Chromatogram of the spiked test solution Figure 5 .like Figure 5 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 6.657min), propylphthalide (retention time 33.333min), epoxide (retention time 35.940min), sec-butylphthalide (retention time 44.757min), butylphthalide (retention time 47.600min), propylenephthalide (retention time 49.027min), pentylphthalide (retention time 61.733min), butylphthalide (retention time 63.287min), pentylphthalide (retention time 79.847min), indicating that butylphthalide is well separated from the eight related substances.

[0076] In Examples 4-5, the column temperature was changed to 35° C. and 25° C., respectively, and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph, and the chromatogram was recorded.

[0077] Example 4: Chromatogram of the spiked test solution Figure 6 .like Figure 6 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 6.337min), propylphthalide (retention time 30.133min), epoxide (retention time 32.233min), sec-butylphthalide (retention time 43.420min), butylphthalide (retention time 45.973min), propylenephthalide (retention time 47.040min), pentylphthalide (retention time 58.583min), butylphthalide (retention time 59.770min), and pentylphthalide (retention time 77.533min), indicating that butylphthalide has a good separation effect with the eight related substances.

[0078] Example 5: Chromatogram of the spiked test solution Figure 7 .like Figure 7As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 7.007min), propylphthalide (retention time 36.847min), epoxide (retention time 39.790min), sec-butylphthalide (retention time 46.113min), butylphthalide (retention time 49.243min), propylenephthalide (retention time 51.083min), pentylphthalide (retention time 64.940min), butylphthalide (retention time 66.937min), pentylphthalide (retention time 81.700min), indicating that butylphthalide has good separation effect with 8 related substances.

[0079] The flow rates of the mobile phase in Examples 6 to 7 were changed to 1.2 mL / min and 0.8 mL / min, respectively, and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph, and the chromatogram was recorded.

[0080] Example 6: Chromatogram of the spiked test solution Figure 8 .like Figure 8 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 5.510min), propylphthalide (retention time 27.373min), epoxide (retention time 29.443min), sec-butylphthalide (retention time 41.783min), butylphthalide (retention time 44.383min), propylenephthalide (retention time 45.437min), pentylphthalide (retention time 56.243min), butylphthalide (retention time 57.393min), pentylphthalide (retention time 75.557min), indicating that the separation effect of butylphthalide and the eight related substances is good.

[0081] Example 7: Chromatogram of the spiked test solution Fig. 9 .like Fig. 9 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 8.407min), propylphthalide (retention time 41.740min), epoxide (retention time 43.110min), sec-butylphthalide (retention time 48.950min), butylphthalide (retention time 52.417min), propylenephthalide (retention time 54.413min), pentylphthalide (retention time 70.010min), butylphthalide (retention time 71.873min), pentylphthalide (retention time 84.423min), indicating that butylphthalide is well separated from the eight related substances.

[0082] The initial ratio of the mobile phase in Examples 8 to 9 was changed to A methanol: B 0.1% phosphoric acid = 45:55, A methanol: B 0.1% phosphoric acid = 55:45, and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into the liquid chromatograph to record the chromatogram.

[0083] Example 8: Chromatogram of the spiked test solution Fig.10 .like Fig.10 As shown, the chromatographic peaks of propylphthalide and epoxide overlap (retention time 17.493 min), and the separation effect is not ideal.

[0084] Example 9: Chromatogram of the spiked test solution Fig.11 .like Fig.11 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 7.900min), propylphthalide (retention time 43.443min), epoxide (retention time 44.180min), sec-butylphthalide (retention time 48.553min), butylphthalide (retention time 51.330min), propylenephthalide (retention time 52.793min), pentylphthalide (retention time 64.950min), butylphthalide (retention time 66.613min), pentylphthalide (retention time 80.607min), indicating that butylphthalide has a good separation effect with the eight related substances.

[0085] The concentration of phosphoric acid in mobile phase B in Examples 10-11 was changed to 0.05% and 0.15%, respectively, that is, the mobile phases were A methanol-B 0.05% phosphoric acid and A methanol-B 0.15% phosphoric acid, respectively, and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into the liquid chromatograph to record the chromatogram.

[0086] Example 10: Chromatogram of the spiked test solution Fig.12 .like Fig.12 As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 6.620min), propylphthalide (retention time 33.000min), epoxide (retention time 35.537min), sec-butylphthalide (retention time 44.637min), butylphthalide (retention time 47.453min), propylenephthalide (retention time 48.833min), pentylphthalide (retention time 61.463min), butylphthalide (retention time 62.947min), and pentylphthalide (retention time 79.620min), indicating that butylphthalide has a good separation effect with the eight related substances.

[0087] Example 11: Chromatogram of the spiked test solution Fig.13 .like Fig.13As shown, each substance and its corresponding retention time are as follows: phthalide (retention time 6.663min), propylphthalide (retention time 33.320min), epoxide (retention time 35.853min), sec-butylphthalide (retention time 44.773min), butylphthalide (retention time 47.617min), propylenephthalide (retention time 49.010min), pentylphthalide (retention time 61.783min), butylphthalide (retention time 63.280min), and pentylphthalide (retention time 79.817min), indicating that butylphthalide has a good separation effect with the eight related substances.

[0088] The main parameters in Examples 2 to 11 are summarized in Table 3.

[0089] Table 3 Main parameters of Examples 2 to 11

[0090]

[0091] The detection method provided by the present invention has strong specificity and good durability. Changing chromatographic conditions such as column flow rate and initial column temperature within a certain range will not affect the separation effect of butylphthalide related substances. The method provided by the present invention can accurately detect 8 related substances in butylphthalide, and the separation between each impurity and between the main component and the impurity is good, and the detection result is accurate and reliable.

[0092] Comparative Example 1

[0093] Compared with Example 1, the mobile phase B in Comparative Example 1 was changed to 0.02 mol / L potassium dihydrogen phosphate (pH 3.0), and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph to record the chromatogram.

[0094] The chromatogram of the spiked test solution of Comparative Example 1 is shown in Fig.14 .like Fig.14 As shown, propylphthalide and epoxide merged into one peak (retention time 30.520 min), and the separation effect was not ideal.

[0095] Comparative Example 2

[0096] Compared with Example 1, the mobile phase B in Comparative Example 2 was changed to 0.2% phosphoric acid, and the other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph to record the chromatogram.

[0097] The chromatogram of the spiked test solution of Comparative Example 2 is shown in Fig.15 . Fig.15 b is a partial enlarged view of the chromatogram at the retention time of 44.503 min. As shown in the figure, sec-butylphthalide is split into two peaks, and the separation effect is not ideal.

[0098] Comparative Example 3

[0099] Compared with Example 1, the chromatographic column in Comparative Example 3 was replaced with Welch Ultimate HPLC Column XB-C18 (4.6*250 mm, 5 μm), and other conditions were the same as in Example 1. 10 μL of the spiked test solution in Example 1 was measured and injected into a liquid chromatograph to record the chromatogram.

[0100] The chromatogram of the spiked test solution of Comparative Example 3 is shown in Fig.16 .like Fig.16 As shown, an unknown impurity peak (retention time 39.373 min) appeared before sec-butylphthalide, and the resolution was 1.21, which could not be effectively separated.

[0101] The results of Comparative Examples 1-3 show that after replacing the mobile phase and chromatographic column and changing the phosphoric acid concentration of mobile phase B over a large range, the related substances in butylphthalide cannot be effectively separated.

Claims

1. A method for detecting related substances in butylphthalide, characterized in that: The method comprises the following steps: Step (1) Sample preparation: Test solution: Take butylphthalide raw material or its preparation, dissolve it in methanol solution, and prepare a butylphthalide solution with a concentration of 1 mg / mL; Reference substance stock solution: weigh 5 mg each of phthalide, propylphthalide, 2-(1-oxopentyl)-benzoic acid, sec-butylphthalide, propylenephthalide, pentylphthalide, butylphthalide, and pentylphthalide impurities into a 50 mL volumetric flask, add methanol to dissolve and dilute to the scale, shake well, and use as the reference substance stock solution; Test sample spike solution: weigh 10 mg of butylphthalide into a 10 mL volumetric flask, add 1 mL of reference stock solution, dilute to the mark with methanol, and shake well to obtain; Step (2) Chromatographic conditions and injection procedure: 10 μL of each of the butylphthalide test solution and the test spiked solution prepared in step (1) were measured and injected into a liquid chromatograph for gradient elution and recording of the chromatogram. 18 The column temperature is set at 25°C to 35°C; methanol or methanol-water solution is used as mobile phase A, phosphoric acid-water solution (0.05%-0.15%) is used as mobile phase B, and gradient elution is performed; the flow rate is 0.5-1.5 mL / min; the detection wavelength is 226-230 nm; the eluent is composed of mobile phase A and mobile phase B, wherein the elution conditions are as follows: ； The reverse phase C 18 The chromatographic column was selected from Inertsil ODS-3, with specifications of 4.6*250mm, 5μm; The related substances include impurities phthalide, propylphthalide, 2-(1-oxopentyl)-benzoic acid, sec-butylphthalide, propylenephthalide, pentylphthalide, butylphthalide, and pentylphthalide, and the structural formula is as follows:

2. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The concentration of the mobile phase B phosphoric acid solution is 0.1%.

3. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The mobile phase A is methanol.

4. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The specifications of the chromatographic column are 4.6*250mm, 5μm.

5. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The flow rate was 1.0 mL / min.

6. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The detection wavelength is 228 nm.

7. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The column temperature was 30°C.

8. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The initial ratio of the mobile phase in the gradient elution program is mobile phase A:mobile phase B=50%:50%.

9. The method for detecting related substances in butylphthalide according to claim 1, characterized in that: The gradient elution procedure is:

10. The method for detecting related substances in butylphthalide according to any one of claims 1 to 9 is used for quality control of butylphthalide raw materials and preparations thereof.

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