WO2020244148A1 - Doramectin crystal form a, crystal form b, and preparation method thereof - Google Patents

Abstract

The present application relates to a doramectin polymorph. Specifically, the present application relates to doramectin crystal form A, crystal form B, and a preparation method thereof. The polymorph can be obtained by dissolving doramectin in a good organic solvent, followed by adding a poor solvent to precipitate crystals, cooling, filtering, and drying. The doramectin polymorph of the present application has the remarkable characteristics of stable physical and chemical properties, high purity, excellent fluidity, excellent yield of the preparation method, and suitability for industrial production.

Description

Doramectin crystal form A, crystal form B and preparation method thereof Technical field

This application belongs to the technical field of veterinary medicine and chemical engineering crystallization, and specifically relates to doramectin crystal form A, crystal form B and preparation methods thereof.

Background technique

Doramectin is a new generation of macrolide antiparasitic drugs developed by Pfizer in the United States in the 1990s. It is considered to be one of the most outstanding drugs among abamectins. Doramectin is a sixteen-membered macrolide semi-synthetic antibiotic produced by a new strain of genetically recombined Streptomyces avermitilis by adding cyclohexanoic acid as a precursor substance. It belongs to the third generation. Avermectin drugs are easily soluble in organic solvents, such as methanol, ethanol, acetone, 1,2-propylene glycol, ethyl acetate, dimethyl sulfoxide, and isopropyl acetate. The structural formula is as follows:

Doramectin is a new, broad-spectrum antiparasitic drug, effective against gastrointestinal nematodes, lung nematodes, mites, ticks and wound maggots, etc. It is used for the treatment of ectoparasitic diseases such as livestock nematodes and mites, mainly applicable For cattle and pigs.

The different solid forms of pharmaceutical or veterinary compounds determine their different physical properties. The difference in physical properties will have an impact on the preparation, processing, formulation or application of pharmaceutical or veterinary compounds. Different crystal forms will cause its stability, solubility, dissolution rate, bulk density, fluidity, suspension stability, stability during grinding, vapor pressure, optical and mechanical properties, hygroscopicity, crystal size, filtration properties, dryness, density Physicochemical properties such as melting point, degradation stability, and stability to prevent conversion to other crystal forms have an important influence, which may cause different efficacy and bioavailability during use. Therefore, for solid medicines, the development of different solid forms is more conducive to choosing a suitable crystal form according to the characteristics of the pharmaceutical preparation.

At present, there are mainly two dosage forms of doramectin, which are mainly used for external use and injections for internal use, both of which have limitations. Pouring agent is a body surface targeted preparation, due to the limitation of the method of administration, the bioavailability is low; although doramectin injection has a good insecticidal effect, it is easy to cause greater stress to sick animals. Not conducive to large-scale drug delivery. Therefore, there is an urgent need to develop new dosage forms of doramectin products, and the development of new dosage forms is inseparable from the development of stable crystal forms to further meet the needs of the veterinary drug market.

The prior art discloses several purification methods of doramectin. For example, Chinese Patent CN 109651465 A discloses that the organic solvents used in the crystallization process are ethyl acetate, ethanol, acetone, preferably ethyl acetate; but these solvents have relatively high solubility , Resulting in lower refined yield. Patent CN 108976270A discloses a purification method that uses acetone/water recrystallization. Due to the high solubility of acetone, a small amount of water is added, and the yield is about 70%, resulting in low purification yield and high production cost. Patent CN104693254A discloses a crystallization method of doramectin to obtain high-purity doramectin. The recrystallization solvent is methanol, ethanol, acetone, isobutanol, isopropanol, or any mixed solvent thereof. Similarly, due to the good solubility of the recrystallization solvent, the refining yield is low. Patent CN 104418927 A discloses a purification method in which the crystallization solvent is an alcohol/water mixed solvent. The alcohol aqueous solution has an alcohol content of more than 90% (V/V), preferably more than 95%, and the amount is 5-10 times (V/W) of the weight of the filter cake. Due to the large proportion of alcohol, the refining yield is low. None of the patents involved the study of crystal forms, which greatly restricted the use of this species in veterinary medicine.

Summary of the invention

The following is an overview of the topics detailed in this article. This summary is not intended to limit the scope of protection of the claims.

This application provides a polymorph of doramectin and a preparation method thereof. The obtained crystal form A and crystal form B have good stability, high purity, and good fluidity; the crystal yield obtained by the preparation process is good, which is suitable for industrial production. It overcomes the shortcomings of related technologies and provides more options for doramectin in the development of new dosage forms.

In the first aspect of this application, two crystal forms of doramectin, crystal form A and crystal form B are provided.

The X-ray powder diffraction pattern of the crystal form A (Figure 1) at 2θ is 6.5±0.2°, 9.4±0.2°, 10.5±0.2°, 11.2±0.2°, 11.5±0.2°, 12.7±0.2°, 13.4± 0.2°, 13.9±0.2°, 14.4±0.2°, 15.2±0.2°, 15.7±0.2°, 16.7±0.2°, 17.1±0.2°, 17.6±0.2°, 18.2±0.2°, 18.5±0.2°, 19.1± There are exclusive characteristic absorption peaks at 0.2°, 19.8±0.2°, 21.3±0.2°, 21.8±0.2°, 22.3±0.2°, 22.7±0.2°, 25.3±0.2°, 27.2±0.2°, 30.4±0.2°.

The X-ray powder diffraction pattern of the crystal form B (Figure 2) at 2θ is 4.4±0.2°, 6.1±0.2°, 6.3±0.2°, 8.7±0.2°, 9.3±0.2°, 10.4±0.2°, 10.7± 0.2°, 11.0±0.2°, 11.2±0.2°, 11.5±0.2°, 12.5±0.2°, 13.3±0.2°, 13.8±0.2°, 14.2±0.2°, 14.4±0.2°, 16.9±0.2°, 17.6± 0.2°, 18.0±0.2°, 18.2±0.2°, 18.5±0.2°, 18.9±0.2°, 19.8±0.2°, 21.4±0.2°, 22.0±0.2°, 22.5±0.2°, 26.8±0.2°, 28.1± There are exclusive characteristic absorption peaks at 0.2°, 33.0±0.2°, and 45.1±0.2°.

Preferably, the X-ray powder diffraction pattern of doramectin crystal form A provided in this application is shown in FIG. 1.

Preferably, the X-ray powder diffraction pattern of doramectin crystal form B provided in this application is shown in FIG. 2.

On the other hand, this application also provides a method for preparing doramectin crystal form A and crystal form B, the steps are as follows:

(1) Put doramectin in a good solvent, dissolve it by heat, and filter;

(2) The filtrate is concentrated under reduced pressure and a poor solvent is added to replace the good solvent, crystals are precipitated, and a certain volume is left. After cooling, the crystallization is continued and filtered and dried to obtain doramectin crystals.

The crystallization equipment used can be a conventional crystallization kettle with stirring effect in this field.

The steps are further explained below:

The good solvent in step (1) is selected from one or more organic solvents such as halogenated hydrocarbons, alcohols, esters, ketones or tetrahydrofuran.

Preferably, the good solvent in step (1) is selected from one or more of tetrahydrofuran, dichloromethane, chloroform, ethyl acetate, acetone, isopropanol, n-butanol, methanol or ethanol.

The dosage ratio (m:v) of the doramectin to the good solvent in step (1) is 1:3-1:5.

Step (2) Concentrate under reduced pressure until the remaining liquid volume is 1-5 times the weight of the solid doramectin, preferably 2-3 times; the volume of the added poor solvent is 1-5 times the weight of the solid doramectin, preferably It is 1-2 times.

The poor solvent for preparing crystal form A in step (2) is selected from one or more of aliphatic hydrocarbon solvents, aromatic hydrocarbons, and ether solvents.

Preferably, the poor solvent for preparing crystal form A in step (2) is selected from n-hexane, cyclohexane, n-heptane, diethyl ether, dimethyl ether, diisopropyl ether, petroleum ether, methyl tert-butyl One or more of ether and toluene.

More preferably, the poor solvent for preparing crystal form A in step (2) is selected from one or more of n-hexane, n-heptane, petroleum ether, methyl tert-butyl ether, toluene, and acetonitrile.

The poor solvent for preparing crystal form B in step (2) is acetonitrile.

The thermal dissolution temperature in step (1) is 20-60°C;

The temperature reduction range of step (2) is -5-15°C, and the drying temperature is 30-80°C.

Benefits:

1. The refining process of this application is simple, easy to operate, and suitable for industrialized production. The purity of doramectin crystals obtained by using this refining process is all above 99%, even up to 99.5%, which greatly improves the efficacy of the drug;

2. The yields of doramectin crystals obtained by this refining process are all above 95%, which greatly reduces the production cost;

3. The polymorphic form obtained by the crystallization process has good stability, no crystal form transformation and no moisture absorption.

After reading and understanding the drawings and detailed description, other aspects can be understood.

Description of the drawings

Figure 1 is an X-ray powder diffraction pattern of doramectin crystal form A prepared in Example 1 of the present application;

Figure 2 is an X-ray powder diffraction pattern of doramectin crystal form B prepared in Example 2 of the present application;

3 is an X-ray powder diffraction pattern of doramectin crystal form A prepared in Example 3 of the present application;

Figure 4 is an HPLC chart of Example 1 of the doramectin crystal prepared by the application;

Fig. 5 is an HPLC chart of Example 2 of doramectin crystals prepared in this application;

Fig. 6 is an HPLC chart of the raw material doramectin in the examples of the present application.

Detailed ways

In order to further illustrate the application, the preferred implementation of the application is described below in conjunction with examples.

General test method:

X-ray powder diffraction (XRD) instrument: Japanese Rigaku D/Max-2500: radiation source: copper target scanning at room temperature: scanning range: 2.0～50.0°, scanning rate: 8°/min, step size: 0.02 °;

Purity check adopts doramectin veterinary pharmacopoeia method: COSMOSIL C18 column (4.6mm×150mm, 5um); mobile phase: methanol:acetonitrile:water=67:15:18(v/v); wavelength: 245nm; flow rate: 1ml/min; injection volume: 20ul.

Example 1

Take 10g of doramectin, add 40ml of tetrahydrofuran, heat to 40℃ to dissolve, concentrate under reduced pressure to 2 times volume, add 20ml of n-hexane, continue to concentrate to 2 times volume, then add 20ml of n-hexane, continue to concentrate to about 1 times volume , Lower the temperature to 0-5°C, filter, and dry 9.6g doramectin on the filter cake at 40-50°C. The yield is 96% and the purity is 99.01%.

The obtained doramectin crystals were tested by XRD and HPLC. The results:

Fig. 1 is an X-ray powder diffraction chart of the doramectin crystal form obtained in Example 1, and Fig. 4 is an HPLC chart of purity detection. It can be seen from Figure 4 that the normalized purity of the main peak is 99.16%. As can be seen from Figure 1, the XRD diffraction 2θ value = 6.5°, 9.4°, 10.5°, 11.2°, 11.5°, 12.7°, 13.4°, 13.9°, 14.4°, 15.2°, 15.7°, 16.7°, 17.1 °, 17.6°, 18.2°, 18.5°, 19.1°, 19.8°, 21.3°, 21.8°, 22.3°, 22.7°, 25.3°, 27.2°, 30.4° have exclusive characteristic absorption peaks. Example 1 obtained doramectin crystal form A.

Example 2

Take 10g of doramectin, add 30ml of acetone, heat to 40℃ to dissolve, concentrate under reduced pressure to 2 times volume, add 20ml of acetonitrile, continue to concentrate to 2 times volume, add 10ml of acetonitrile, continue to concentrate to 1-2 times volume, Cool down to -5-0°C, keep stirring for 1 hour, filter, and dry the filter cake at 50-60°C to dry 9.5g of doramectin, with a yield of 95% and a purity of 99.54%.

The obtained doramectin crystals were tested by XRD and HPLC. The results:

Fig. 2 is an X-ray powder diffraction pattern of the doramectin crystal form obtained in Example 2, and Fig. 5 is an HPLC pattern of purity detection. It can be seen from Figure 2 that the 2θ values are 4.4°, 6.1°, 6.3°, 8.7°, 9.3°, 10.7°, 11.0°, 11.2°, 11.5°, 12.5°, 13.3°, 13.8°, 14.2° , 14.4°, 16.9°, 17.6°, 18.0°, 18.2°, 18.5°, 18.9°, 19.8°, 21.4°, 22.0°, 22.5°, 26.8°, 28.1°, 33.0°, 45.1° with exclusive characteristic absorption peak. It can be seen from Figure 5 that the normalized purity of the main peak is 99.54%. Example 2 obtained doramectin crystal form B.

Example 3

Take 10g of doramectin, add 50ml of methanol, heat to 40℃ to dissolve, concentrate under reduced pressure to 2 times volume, add 20ml of toluene, continue to concentrate to 2 times volume, add 10ml of toluene, continue to concentrate to about 1 times volume, cool down To 10-15°C, filter, the filter cake is dried at 60-80°C with 9.8 g of doramectin, the yield is 98%, and the purity is 99.45%.

XRD test was performed on the obtained doramectin crystals, and the results:

XRD diffraction 2θ value = 6.4°, 9.3°, 10.3°, 11.0°, 12.4°, 13.3°, 14.2°, 15.0°, 15.6°, 16.6°, 17.0°, 17.3°, 17.7°, 18.2°, 19.0° There are exclusive characteristic absorption peaks at, 22.3° and 27.0°. Example 3 obtained doramectin crystal form A.

Example 4

Take 10g of doramectin, add 30ml of dichloromethane, heat to 35℃ to dissolve, concentrate under reduced pressure to 1 volume, add 15ml of acetonitrile, continue to concentrate to 2 times volume, add 20ml of acetonitrile, continue to concentrate to about 1 volume , Lower the temperature to -5-0°C, filter, and dry 9.9g of doramectin on the filter cake at 40-50°C. The yield is 99% and the purity is 99.68%.

XRD test was performed on the obtained doramectin crystals, and the results:

XRD diffraction 2θ value = 4.5°, 6.2°, 6.5, 9.5°, 10.4, 11.2°, 12.6°, 13.4°, 13.9, 14.4°, 16.9°, 17.7°, 18.1°, 18.4°, 18.7°, 20.0° There are exclusive characteristic absorption peaks at, 21.5°, 22.7°, 26.9°, 28.2°, 33.2°, 45.3°. Example 4 obtained doramectin crystal form B.

Example 5

Take 10g of doramectin, add 35ml of ethanol, heat to 50℃ to dissolve, concentrate under reduced pressure to 1 volume, 20ml of n-heptane, continue to concentrate to 2 times the volume, then add 10ml of n-heptane, continue to concentrate to about 1 times The volume is cooled to 0-5°C, filtered, and the filter cake is dried at 50-60°C for 9.9 g of doramectin, the yield is 99%, and the purity is 99.72%.

XRD test was performed on the obtained doramectin crystals, and the results:

XRD diffraction 2θ value = 6.5°, 9.4°, 10.5°, 11.2°, 11.5°, 12.6°, 13.3°, 13.8°, 14.6°, 15.2°, 15.9°, 16.7°, 17.1°, 17.6°, 18.2° There are exclusive characteristic absorption peaks at, 18.6°, 19.2°, 19.7°, 21.4°, 21.8°, 22.4°, 22.7°, 25.5°, 27.3°, 30.5°. Example 5 obtained doramectin crystal form A.

Example 6 Stability study

The stability study of this polymorph was carried out and the results are as follows:

Table 1 Stability of doramectin crystal form

Experimental results show that:

Under the experimental conditions in the above table, the doramectin crystal form obtained in this application has no obvious changes in content, appearance and crystal form, and has good stability. It has no hygroscopicity and can be better applied to pharmaceutical preparations.

The crystal form A and crystal form B of doramectin proposed in this application and the preparation method thereof have been described in the examples. It should be understood that these descriptions are only to further illustrate the features and advantages of this application, not to the claims of this application. limit.

Claims (10)

1. A doramectin crystal form A. In the X-ray powder diffraction pattern measured by CuKa rays, the characteristic peaks 2θ of the crystal form A are at 6.5±0.2°, 9.4±0.2°, 10.5±0.2°, 11.2 ±0.2°, 11.5±0.2°, 12.7±0.2°, 13.4±0.2°, 13.9±0.2°, 14.4±0.2°, 16.7±0.2°, 17.1±0.2°, 17.6±0.2°, 18.2±0.2°, 18.5 There are characteristic peaks at ±0.2°, 19.8±0.2°, 21.3±0.2°, 21.8±0.2°, 22.3±0.2°, 22.7±0.2° and 27.2±0.2°.
2. The doramectin crystal form A according to claim 1, wherein, in the powder diffraction pattern obtained by using CuKa rays, the characteristic peaks of the crystal form A further include 2θ of 15.2±0.2°, 15.7±0.2°, One or more of 19.1±0.2°, 25.3±0.2°, 30.4±0.2°.
3. A doramectin crystal form B, in the X-ray powder diffraction pattern measured by CuKa rays, the characteristic peaks 2θ of the crystal form B are at 4.4±0.2°, 6.1±0.2°, 6.3±0.2°, 9.3 ±0.2°, 10.4±0.2°, 12.5±0.2°, 13.3±0.2°, 13.8±0.2°, 16.9±0.2°, 17.6±0.2°, 18.0±0.2°, 18.2±0.2°, 18.5±0.2°, 21.4 There are characteristic peaks at ±0.2°, 22.5±0.2° and 26.8±0.2°.
4. The doramectin crystal form B according to claim 3, wherein, in the powder diffraction pattern obtained by using CuKa rays, the characteristic peaks of the crystal form B further include 2θ of 8.7±0.2°, 10.7±0.2°, 11.0±0.2°, 11.2±0.2°, 11.5±0.2°, 14.2±0.2°, 14.4±0.2°, 18.9±0.2°, 19.8±0.2°, 22.0±0.2°, 28.1±0.2°, 33.0±0.2°, One or more of 45.1±0.2°.
5. According to the preparation method of doramectin crystal form according to any one of claims 1-4, the steps of the preparation method are:

   (1) Dissolve doramectin in a good organic solvent and filter;

   (2) The filtrate is concentrated under reduced pressure and a poor solvent is added to replace the organic good solvent, and crystals are precipitated, the temperature is lowered to continue crystallization, and then filtered and dried to obtain a doramectin crystal form.
6. The method for preparing doramectin crystal form according to claim 5, wherein the organic good solvent in step (1) is selected from one of halogenated hydrocarbons, alcohols, esters, ketones, and tetrahydrofuran Or several.
7. The method for preparing doramectin crystal form according to claim 6, wherein the organic good solvent in step (1) is selected from tetrahydrofuran, dichloromethane, chloroform, ethyl acetate, acetone, isopropanol, normal One or more of butanol, methanol and ethanol.
8. The method for preparing doramectin crystal form according to claim 5, wherein when the poor solvent in step (2) is selected from one of aliphatic hydrocarbon solvents, aromatic hydrocarbons, and ether solvents, When there are several types, doramectin crystal form A is prepared; when the poor solvent in step (2) is acetonitrile, doramectin crystal form B is prepared.
9. The method for preparing doramectin crystal form according to claim 8, wherein in step (2), the poor solvent for preparing doramectin crystal form A is selected from n-hexane, cyclohexane, n-heptane, One or more of ether, dimethyl ether, diisopropyl ether, petroleum ether, methyl tert-butyl ether and toluene.
10. The method for preparing doramectin crystal form according to claim 5, wherein in step (1), the weight-volume ratio of the doramectin to the organic good solvent is 1:3 to 1:5 , The temperature of thermal dissolution is 20-60°C; in step (2), the weight-volume ratio of the doramectin to the poor solvent is 1:1 to 1:5, and the temperature after cooling is -5- 15℃, the drying temperature is 30-80℃.

Images