Pebiprofen ammonium salt as well as crystal form, preparation method and application thereof

Abstract

The invention discloses a pebiprofen ammonium salt as well as a crystal form, a preparation method and application thereof, relates to the technical field of medicinal chemistry, and provides the pebiprofen ammonium salt and the crystal form of the pebiprofen ammonium salt which are not disclosed in the prior art for the first time. Animal experiments show that compared with the pebiprofen free acid, the pebiprofen sodium salt and the pebiprofen tromethamine salt, the pebiprofen ammonium salt disclosed by the invention shows better pharmacokinetic characteristics, and an important basis is provided for developing a novel pebiprofen dosage form. In addition, the invention further provides a simple, convenient and efficient preparation process of the pebiprofen ammonium salt, the operability and repeatability are good, and an innovative technical path is provided for industrial production of high-added-value preparations.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical chemistry, and in particular to a pebiprofen ammonium salt and a crystal form, a preparation method and application thereof. Background Art

[0002] Pelubiprofen, also known as pelubiprofen, is a nonsteroidal anti-inflammatory drug that reduces prostaglandin synthesis by inhibiting cyclooxygenase activity. It is widely used clinically to treat osteoarthritis, rheumatoid arthritis, and for postoperative analgesia. Although its efficacy and safety have been clinically validated, the free acid form of pelubiprofen suffers from poor water solubility and significant fluctuations in oral bioavailability, making it difficult to meet the requirements of immediate-release formulations and high-dose administration.

[0003] To optimize the physicochemical properties of drugs, salt-forming technology has become a key strategy. For example, Chinese patents CN113891873A and CN114533685A disclose methods for preparing pebiprofen tromethamine salts, which significantly improve water solubility and reduce gastrointestinal irritation through salt conversion. However, tromethamine has cell membrane permeability, which may interfere with intracellular acid-base balance, has potential toxicity, and is contraindicated in patients with chronic respiratory acidosis and renal acidosis. On the other hand, Korean patent 10-2004-0002890 reports the preparation of pebiprofen transdermal patches in the form of alkali metal salts (such as sodium salts and potassium salts), but the synthesis process and crystal form control technology of the sodium salt are not deeply explored.

[0004] Crystal form research is a core component of drug development. Different crystal forms can significantly affect drug dissolution, mechanical properties, and formulation stability. Currently, research on the crystal forms of pebiprofen remains limited: Chinese patent CN111039782A discloses a highly stable crystal form that is resistant to moisture absorption under high temperature and humidity conditions, but fails to overcome the bottleneck of the free acid's poor water solubility. Notably, existing literature and patents lack research on the ammonium salt of pebiprofen and its crystal forms.

[0005] In summary, the existing technology has the following limitations: ① Tromethamine salts are limited by toxic side effects; ② Alkali metal salts lack a crystal form control scheme; ③ Existing crystal forms cannot simultaneously achieve high stability and high solubility. In response to the above problems, the present invention innovatively adopts an ammonia deesterification and simultaneous salt formation process to successfully prepare a new crystal form of pebiprofen ammonium salt with a rod-shaped microcrystalline structure. Animal experiments show that this crystal form not only has a significant analgesic effect, but also, compared with pebiprofen free acid, sodium salt and tromethamine salt, the pebiprofen ammonium salt prepared by the present invention exhibits better pharmacokinetic properties, and the process route is more suitable for industrial production. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a pebiprofen ammonium salt and its crystal form and preparation method. A new pebiprofen ammonium salt crystal form with a rod-shaped microcrystalline structure is successfully prepared through an innovative process of removing the ester group with ammonia water and simultaneously generating the pebiprofen ammonium salt. Animal experiments show that the crystal form exhibits excellent pharmacokinetic properties, and its analgesic effect is significantly improved compared with the existing preparation lysine aspirin.

[0007] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0008] One of the objects of the present invention is to provide a pebiprofen ammonium salt, the structural formula of which is as follows:

[0009]

[0010] A second object of the present invention is to provide a method for preparing a pebiprofen ammonium salt, comprising the following steps:

[0011] (1) The pebiprofen intermediate undergoes hydrolysis to obtain pebiprofen;

[0012] (2) Pebiprofen reacts with aqueous ammonia to form a salt to obtain a pebiprofen ammonium salt;

[0013] The structural formula of the pebiprofen intermediate is as follows:

[0014]

[0015] Wherein, R is selected from any one of an alkyl group, an ester group, and an aryl group.

[0016] In some embodiments, R is selected from any one of tert-butyl, methyl, ethyl, and benzyl.

[0017] The third object of the present invention is to provide a crystalline form of a pebiprofen ammonium salt, the X-ray powder diffraction pattern of which has characteristic peaks at 2θ values ​​of 22.47±0.2°, 20.66±0.2°, 18.46±0.2°, and 10.30±0.2°.

[0018] In some specific embodiments, the X-ray powder diffraction pattern of the crystalline form of pebiprofen ammonium salt has characteristic peaks at 2θ values ​​of 26.05±0.2°, 25.46±0.2°, 22.47±0.2°, 21.91±0.2°, 20.83±0.2°, 20.66±0.2°, 18.46±0.2°, 15.90±0.2°, 14.10±0.2°, 12.96±0.2°, and 10.30±0.2°.

[0019] In some specific embodiments, the X-ray powder diffraction pattern of the crystalline form of the ammonium salt of pegbiprofen has characteristic peaks at 2θ values ​​of 28.13±0.2°, 26.05±0.2°, 25.46±0.2°, 22.47±0.2°, 21.91±0.2°, 20.83±0.2°, 20.66±0.2°, 18.46±0.2°, 17.97±0.2°, 16.69±0.2°, 15.90±0.2°, 14.10±0.2°, 13.59±0.2°, 12.96±0.2°, and 10.30±0.2°.

[0020] Furthermore, the X-ray powder diffraction pattern is measured using Cu-Kα radiation.

[0021] A fourth object of the present invention is to provide a method for preparing a crystalline form of pebiprofen ammonium salt, wherein the crystalline form of pebiprofen ammonium salt is obtained by recrystallizing the crystalline form of pebiprofen ammonium salt with isopropyl alcohol.

[0022] Furthermore, the HPLC purity of the pebiprofen ammonium salt crystal is greater than 99.8%, and the maximum single impurity content is less than 0.1%.

[0023] Furthermore, the crystal form of the pebiprofen ammonium salt is a rod-shaped microcrystalline structure.

[0024] A fifth object of the present invention is to provide the use of the pebiprofen ammonium salt or the pebiprofen ammonium salt crystal in the preparation of non-steroidal anti-inflammatory drugs, prostaglandin synthesis inhibitors and analgesics.

[0025] The beneficial effects of the present invention are:

[0026] 1. This invention reports for the first time the preparation method and crystal structure of pebiprofen ammonium salt, filling a gap in the prior art. This novel compound provides a new material basis for the development of innovative pebiprofen dosage forms.

[0027] 2. This invention innovatively discovered the rod-shaped microcrystal morphology of pebiprofen ammonium salt, a crystal structure disclosed internationally for the first time. This crystal form possesses unique physical and chemical properties, creating favorable conditions for the development of novel drug delivery systems such as sustained-release formulations and transdermal delivery.

[0028] 3. To address the shortcomings of existing synthesis processes, the present invention provides an innovative one-step salt formation method in an acidic system. Compared to the traditional process (which requires a three-step reaction of alkaline deprotection, acidification, and salt formation), the present invention simultaneously completes the deprotection of the carboxyl group and the salt formation reaction with ammonia under acidic conditions, effectively avoiding side reactions caused by a strong alkaline environment, and the prepared pebiprofen ammonium salt is of high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is the H NMR spectrum of the pebiprofen ammonium salt prepared in Example 1;

[0030] Figure 2 The scanning X-ray powder diffraction (XRPD) pattern of the pebiprofen ammonium salt prepared in Example 1;

[0031] Figure 3 HPLC chart of the pebiprofen ammonium salt prepared in Example 1;

[0032] Figure 4 HPLC chart of the pebiprofen ammonium salt prepared in Example 2;

[0033] Figure 5 This is a confocal microscopy image of the pebiprofen ammonium salt prepared in Example 1;

[0034] Figure 6 The blood concentration-time curves of the pebiprofen ammonium salt, pebiprofen free acid, pebiprofen sodium salt and pebiprofen tromethamine prepared in Example 1 are shown. DETAILED DESCRIPTION

[0035] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments and illustrations.

[0036] Example 1

[0037] Synthesis of Pebiprofen Ammonium Salt:

[0038]

[0039] Compound 1 (100 g, 0.318 mol) dissolved in 200 g of ethanol was added dropwise to 600 mL of dilute hydrochloric acid (1 M) at 0°C, followed by stirring and reacting at 0°C for 2 h. A solid precipitated and was filtered to obtain crude pebiprofen. The crude pebiprofen was dissolved in 500 mL of acetone, and 200 mL of 25% ammonia water was added dropwise at 0°C. The mixture was reacted at 0°C for 1 h. A solid precipitated and was filtered to obtain pebiprofen ammonium salt. The pebiprofen ammonium salt was heated to reflux with 800 mL of isopropanol until completely dissolved. After stopping stirring, the mixture was cooled naturally to crystallize. The filter cake was collected and dried to obtain a brown needle-shaped solid with a yield of 86%. 1 H NMR (400 MHz, D2O) δ7.38-7.20 (m, 5H), 3.60 (q, J = 7.2 Hz, 1H), 2.69-2.54 (m, 2H), 2.45-2.27 (m, 2H), 1.77-1.64 (m, 2H), 1.58-1.47 (m, 2H), 1.36 (d, J = 7.2 Hz, 3H); see the specific spectrum. Figure 1 .

[0040] The XRPD data of the pebiprofen ammonium salt crystal prepared in Example 1 was measured using a Bruker D8 ADVANCE analyzer. The detection parameters are shown in Table 1. The XRPD pattern is shown in Table 1. Figure 2 .

[0041] Table 1 XRPD test parameters of pebiprofen ammonium salt crystal form

[0042] from Figure 2 It can be seen that the XRPD spectrum of the crystalline form of pebiprofen ammonium salt has characteristic peaks at 2θ values ​​of 28.13±0.2°, 26.05±0.2°, 25.46±0.2°, 22.47±0.2°, 21.91±0.2°, 20.83±0.2°, 20.66±0.2°, 18.46±0.2°, 17.97±0.2°, 16.69±0.2°, 15.90±0.2°, 14.10±0.2°, 13.59±0.2°, 12.96±0.2°, and 10.30±0.2°, and the height % of these diffraction peaks are all greater than 10.

[0043] HPLC data acquisition was performed on the crystalline form of the ammonium salt of pebiprofen prepared in Example 1 using an Agilent 1260 high performance liquid chromatograph. The specific instrument and experimental parameters are shown in Table 2. The HPLC spectrum is shown in Figure 3 .

[0044] Table 2 HPLC test parameters of pebiprofen ammonium salt crystal form

[0045] project parameter Chromatographic columns Hypeisil ODS2 4.6*150mm,5μm Detection wavelength 220nm Injection volume 2μL flow rate 1ml / min Elution method Gradient elution Column temperature 35℃ Mobile phase Acetonitrile / water = 30:70 (V / V) time 40min

[0046] from Figure 3 It can be seen that the purity of the crystalline form of the pegbiprofen ammonium salt prepared in Example 1 is greater than 99.85%, and the maximum single impurity content is less than 0.1%.

[0047] The crystal form of the ammonium salt of pebiprofen prepared in Example 1 was observed to be a rod-shaped microcrystalline structure using an A1 HD25 Nikon single-photon confocal microscope. The scale is 5 μm. The confocal microscope image is shown in FIG. Figure 5 .

[0048] Example 2

[0049] Synthesis of Pebiprofen Ammonium Salt:

[0050]

[0051] Compound 2 (100 g, 0.367 mol) dissolved in 200 g of ethanol was added dropwise to 600 mL of dilute hydrochloric acid (3 M) at 0°C, followed by stirring at 50°C for 2 h, cooling to 0°C, precipitating a solid, and filtering to obtain crude pebiprofen. The crude pebiprofen was dissolved in 500 mL of acetone, and 200 mL of 25% ammonia water was added dropwise at 0°C, and reacted at 0°C for 1 h. A solid precipitated and was filtered to obtain pebiprofen ammonium salt. The pebiprofen ammonium salt was heated to reflux with 800 mL of isopropanol until completely dissolved. After stopping stirring, the mixture was cooled naturally to crystallize, filtered, and the filter cake was collected and dried to obtain a brown needle-shaped solid with a yield of 73%.

[0052] HPLC data acquisition was performed on the crystalline form of the ammonium salt of pebiprofen prepared in Example 2 using an Agilent 1260 high performance liquid chromatograph. The specific instrument and experimental parameters are shown in Table 2. The HPLC spectrum is shown in Figure 4 .

[0053] from Figure 4 It can be seen that the purity of the crystalline form of the pebiprofen ammonium salt prepared in Example 2 is 99.89%, and the maximum single impurity is 0.11%.

[0054] Example 3

[0055] Synthesis of Pebiprofen Ammonium Salt:

[0056]

[0057] Compound 3 (100 g, 0.350 mol) dissolved in 200 g of ethanol was added dropwise to 600 mL of dilute hydrochloric acid (3 M) at 0°C, followed by stirring at 50°C for 2 h, cooling to 0°C, precipitating a solid, and filtering to obtain crude pebiprofen. The crude pebiprofen was dissolved in 500 mL of acetone, and 200 mL of 25% ammonia water was added dropwise at 0°C, and reacted at 0°C for 1 h. A solid precipitated and was filtered to obtain pebiprofen ammonium salt. The pebiprofen ammonium salt was heated to reflux with 800 mL of isopropanol until completely dissolved. After stopping stirring, the temperature was naturally lowered to crystallize, filtered, and the filter cake was collected and dried to obtain a brown needle-shaped solid with a yield of 70%.

[0058] Example 4

[0059] Synthesis of Pebiprofen Ammonium Salt:

[0060]

[0061] Compound 4 (100 g, 0.287 mol) dissolved in 200 g of ethanol was added dropwise to 600 mL of dilute hydrochloric acid (3 M) at 0°C, followed by stirring at 50°C for 2 h, cooling to 0°C, precipitating a solid, and filtering to obtain crude pebiprofen. The crude pebiprofen was dissolved in 500 mL of acetone, and 200 mL of 25% ammonia water was added dropwise at 0°C, and reacted at 0°C for 1 h. A solid precipitated and was filtered to obtain pebiprofen ammonium salt. The pebiprofen ammonium salt was heated to reflux with 800 mL of isopropanol until completely dissolved. After stopping stirring, the temperature was naturally lowered to crystallize, filtered, and the filter cake was collected and dried to obtain a brown needle-shaped solid with a yield of 55%.

[0062] Pharmacokinetic studies

[0063] BALB / c mice are divided into five groups at random, 5 in every group, be respectively blank control group (blank group), pebiprofen ammonium salt test group (test group), pebiprofen free acid control group (control group 1), pebiprofen sodium salt control group (control group 2), pebiprofen tromethamine control group (control group 3).The drug concentration of test group and control group 1-3 is 10 μM (being dissolved in 300 μ L PBS solution).At predetermined time point (0h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h after injection), collect blood sample from submandibular vein.Blood sample is centrifuged for 15min under rotating speed 16000r / min, to obtain blood plasma.By HPLC, measure the concentration change of pebiprofen ammonium salt and pebiprofen in blood plasma, according to the ratio of peak area and peak area at 0 o'clock, draw the time-varying relation curve of blood drug concentration.

[0064] Figure 6 The blood concentration-time curves of the pebiprofen ammonium salt, pebiprofen free acid, pebiprofen sodium salt and pebiprofen tromethamine prepared in Example 1 are shown. Figure 6 It can be seen that the metabolic clearance rate of the pebiprofen ammonium salt prepared by the present invention in mice is slower than that of pebiprofen free acid, pebiprofen sodium salt and pebiprofen tromethamine, which indicates that the pebiprofen ammonium salt can exert anti-inflammatory and analgesic effects more sustainably. Therefore, the pebiprofen ammonium salt prepared by the present invention has great clinical translation value.

[0065] Mouse analgesia experiment

[0066] Using the acetic acid writhing method, BALB / c mice were randomly divided into five groups, with 10 mice in each group. Group 1 was a blank control group, Group 2 was a positive control group (lysine aspirin), Group 3 was a low-dose group of pebiprofen ammonium salt, Group 4 was a medium-dose group of pebiprofen ammonium salt, and Group 5 was a high-dose group of pebiprofen ammonium salt. The samples of each group were diluted and injected through the tail vein. The blank control group was given an equal volume of water for injection. 30 minutes after administration, 0.2 mL of acetic acid solution (0.6%) was injected intraperitoneally into each mouse. The number of writhing reactions of the mice within 5 to 30 minutes after the injection of acetic acid solution was observed and recorded, and the analgesic rate was calculated according to the following formula. The results are shown in the figure.

[0067] As shown in Table 3.

[0068]

[0069] Table 3 Analgesic results of pebiprofen ammonium salt

[0070] Serial number Group Dosage Average number of writhing reactions Analgesia rate 1 Blank control group / 63.2 / 2 Positive control group 100 44.4 29.7％ 3 Pebiprofen ammonium low dose group 3 42.7 32.4％ 4 Pebiprofen ammonium salt medium dose group 12 28.8 54.4％ 5 Pebiprofen ammonium high dose group 48 15.6 75.3％

[0071] As can be seen from Table 3, the average number of writhing reactions in mice injected with the low, medium, and high doses of pebiprofen ammonium salt was significantly lower than that in the blank control group, while the average number of writhing reactions in the medium and high dose groups was also significantly lower than that in the positive control group. This indicates that the pebiprofen ammonium salt of the present invention has a significant analgesic effect at all tested doses, and therefore, pebiprofen ammonium salt has important clinical translation value.

[0072] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A pebiprofen ammonium salt, characterized in that The structural formula of the pebiprofen ammonium salt is as follows:

2. A method for preparing a pebiprofen ammonium salt, characterized in that: The following steps are involved: (1) The pebiprofen intermediate undergoes hydrolysis to obtain pebiprofen; (2) Pebiprofen reacts with aqueous ammonia to form a salt to obtain a pebiprofen ammonium salt; The structural formula of the pebiprofen intermediate is as follows: Wherein, R is selected from any one of an alkyl group, an ester group, and an aryl group; The structural formula of the pebiprofen ammonium salt is as follows:

3. The preparation method of pebiprofen ammonium salt according to claim 2, wherein: R is selected from any one of tert-butyl, methyl, ethyl and benzyl.

4. A pebiprofen ammonium salt crystal form, characterized in that: The X-ray powder diffraction pattern of the pebiprofen ammonium salt crystal has characteristic peaks at 2θ values ​​of 22.47±0.2°, 20.66±0.2°, 18.46±0.2°, and 10.30±0.2°.

5. The pebiprofen ammonium salt crystal form according to claim 4, wherein: The X-ray powder diffraction pattern of the crystalline form of the ammonium salt of pegbiprofen has characteristic peaks at 2θ values ​​of 26.05±0.2°, 25.46±0.2°, 22.47±0.2°, 21.91±0.2°, 20.83±0.2°, 20.66±0.2°, 18.46±0.2°, 15.90±0.2°, 14.10±0.2°, 12.96±0.2°, and 10.30±0.2°.

6. The pebiprofen ammonium salt crystal form according to claim 4, wherein: The X-ray powder diffraction pattern of the crystalline form of the ammonium salt of pegbiprofen has characteristic peaks at 2θ values ​​of 28.13±0.2°, 26.05±0.2°, 25.46±0.2°, 22.47±0.2°, 21.91±0.2°, 20.83±0.2°, 20.66±0.2°, 18.46±0.2°, 17.97±0.2°, 16.69±0.2°, 15.90±0.2°, 14.10±0.2°, 13.59±0.2°, 12.96±0.2°, and 10.30±0.2°.

7. The crystalline form of pebiprofen ammonium salt according to claim 4, wherein: The X-ray powder diffraction pattern was measured using Cu-Kα radiation.

8. A method for preparing a crystalline form of pebiprofen ammonium salt, characterized in that: The pebiprofen ammonium salt prepared by the preparation method of pebiprofen ammonium salt according to any one of claims 2 to 3 is recrystallized with isopropyl alcohol to obtain a pebiprofen ammonium salt crystal form.

9. The method for preparing the pebiprofen ammonium salt crystal according to claim 8, wherein: The HPLC purity of the pebiprofen ammonium salt crystal is greater than 99.8%, and the maximum single impurity content is less than 0.1%; Preferably, the crystal form of the pebiprofen ammonium salt is a rod-shaped microcrystalline structure.

10. Use of the pebiprofen ammonium salt according to claim 1, or the pebiprofen ammonium salt prepared by the method for preparing the pebiprofen ammonium salt according to any one of claims 2 to 3, or the pebiprofen ammonium salt crystal form according to any one of claims 4 to 7, or the pebiprofen ammonium salt crystal form prepared by the method for preparing the pebiprofen ammonium salt crystal form according to any one of claims 8 to 9 in the preparation of non-steroidal anti-inflammatory drugs, prostaglandin synthesis inhibitors and analgesics.

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