CN111375071B

CN111375071B - Method for preparing contrast agent

Info

Publication number: CN111375071B
Application number: CN201911355178.7A
Authority: CN
Inventors: 李明; 梁蕊蕊; 刘凯
Original assignee: Jiangsu Hengrui Medicine Co Ltd
Current assignee: Jiangsu Hengrui Medicine Co Ltd
Priority date: 2018-12-26
Filing date: 2019-12-25
Publication date: 2023-04-07
Anticipated expiration: 2039-12-25
Also published as: CN111375071A

Abstract

The present invention provides a method of preparing a contrast agent. Specifically, the liquid composition of the complex containing the macrocyclic chelate and the lanthanide is sequentially subjected to Relite CNS cationic resin and Relite3As anionic resin to obtain a high-purity liquid solution, then the pH value of the solution is adjusted, and then the solution is subjected to freeze drying or low-temperature spray drying to obtain a contrast agent solid, and a quantitative solid is further weighed to prepare a contrast agent preparation for medical contrast.

Description

Method for preparing contrast agent

Technical Field

The invention relates to a preparation method of a contrast agent, in particular to a gadolinium-based agent with a contrast effect.

Background

Magnetic resonance imaging is an effective, non-invasive technique for two-dimensional or three-dimensional anatomical imaging of tissues in the body. Many lanthanide-based chelates, particularly with gadolinium, have been widely used as contrast agents for magnetic resonance imaging. Such as meglumine gadotetate (meglumine gadotetate, DOTA-Gd,1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid gadobenzymethyl), gadobutrol (HPDO) ₃ A) And the linear chelates DTPA (diethylenetriaminepentaacetic acid) and DTPA-BMA (gadolinium diamine)

According to the literature reports, the general outline of the preparation process of the meglumine gadotetate is as follows:

US4963344 discloses using cycleanine as raw material, performing N-nucleophilic substitution with chloroacetic acid, acidifying, and mixing with meglumine and Gd ₂ O ₃ Complexing, namely preparing the meglumine gadoterate by a one-pot method. However, the document does not provide a method for effectively removing impurities and inorganic salts in the crude product of meglumine gadotetate,

U.S. Pat. No. 5,5428156A is prepared from cyclen by Mannich reaction to produce intermediate 6, hydrolysis under LiOH catalysis to obtain 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (also called DOTA), complexation with gadolinium oxide, and reaction with meglumine to produce meglumine gadoterate. Potassium cyanide in the process is a highly toxic product and is a potential risk to both process operators and the environment. On the other hand, the process does not provide a method for effectively removing impurities and inorganic salts in the crude product of the meglumine gadoterate,

wangler et al (Bioorganic & Medicinal Chemistry,16,2606-2616, 2008) reported that cyclen and ethyl chloroacetate were used as raw materials, and reacted with meglumine after N-nucleophilic substitution, ester hydrolysis, acidification, and complexation with gadolinium to generate gadoteric acid meglumine. The reaction process can generate a large amount of sodium chloride which is removed by an organic phase extraction method, the effect is poor, and the problem of residual solution caused by the salt removal by using an organic solvent is not beneficial to the quality control of the final product,

CN10622058A discloses a method for purifying meglumine gadotetate by using methanol/acetone system. The process can achieve the effect of purifying the crude product of the meglumine gadotetate to a certain extent, but the process can not effectively remove the salt in the sample due to the limited solubility of the solvent to the inorganic salt.

CN108658882A discloses a process for refining with water to obtain high-purity DOTA and further utilizing the intermediate to prepare meglumine gadoterate. The process adopts 001 multiplied by 7 strong acid cation resin to purify the crude product of the meglumine gadotetate, wherein the 001 multiplied by 7 resin belongs to macroporous adsorption resin which is easy to swell and degrade, and the strong acid resin is strong in adsorption capacity and strong in adsorption capacity to a sample, so that the yield of the final product is low.

In another aspect, for example, CN101977633A describes the preparation of a crude liquid pharmaceutical formulation containing 0.002 to 0.4% concentration of free macrocyclic chelate and zero free gadolinium by adding additional free gadolinium or macrocyclic chelate, such as 1,4,7, 10-tetraazacyclododecane-1, 4,7, 10-tetraacetic acid, followed by desalting with an ionic resin or nanofiltration membrane and filling to obtain the final liquid formulation. The process does not relate to the preparation of meglumine gadotetate solid. As an injectable product for diagnosis, it is necessary to detect its free gadolinium and free macrocyclic ligand content with extreme precision, the intended target cannot be effectively addressed by the addition of non-metered amounts of free gadolinium or macrocyclic chelate, and the final pharmaceutical solution of excess free macrocyclic chelate within the target range cannot be reproduced on an industrial scale.

Based on this, although the pharmaceutical researchers know that conventional ionic resins or nanofiltration membranes can be used to purify the contrast agent solution, the existing literature does not give details on the method for purifying the contrast agent such as meglumine gadotetate. In addition, nanofiltration is used to remove single ions from higher valency ions or from higher molecular weight compounds, WO2011054480 reports that the removal of ions from gadobutrol by nanofiltration is possible, but this technique is only applicable to the purification of complexes and not to ionic contrast agents such as gadotetrac acid meglumine. Therefore, there is a need for pharmaceutical researchers to develop a process that is simple and feasible, and suitable for industrial production.

Disclosure of Invention

The invention provides a method for preparing a contrast agent, which comprises the following steps:

a) Preparing a liquid composition comprising: complexes of macrocyclic chelates with lanthanides,

b) Treating the liquid composition of step a) with a cationic resin selected from the group consisting of Relite CNS,

c) Treating the solution resulting from step b) with an anionic resin selected from the group consisting of Relite3As,

wherein said macrocyclic chelate is selected from the group consisting of DOTA, NOTA, DOTAGA, DO ₃ A、BT-DO ₃ A (gadobutrol), HP-DO ₃ A or PCTA, preferably DOTA.

For the purposes of the present invention, in the preparation of the liquid composition in step a), the amounts of lanthanide and macrocyclic chelate are in accordance with the stoichiometry of the complexation reaction. In alternative embodiments, the macrocyclic chelate/lanthanide molar ratio (mol/mol) in the liquid composition is in the range of 1.2 to 0.8, and may be 1.1, 1.05, 1.0, 0.95, 0.9, 0.85, 0.8, preferably 1.05 to 0.95.

The lanthanide is added to step a) in the present invention in a form well known to those skilled in the art, such as in the form of an oxide or other salt.

In some embodiments, the temperature of the complexation reaction in step a) is between 60 ℃ and 100 ℃, and may be 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, preferably 80 ℃.

In some embodiments, the pharmaceutical composition is cooled prior to step b). The reaction time in step a) is about 1 to 4 hours.

In another aspect of the present invention, the liquid composition of step a) in the process of the present invention further comprises meglumine.

In an alternative embodiment, the amount of meglumine in step a) of preparation of the liquid composition in which the macrocyclic chelate/meglumine molar ratio (mol/mol) is between 1.2 and 0.8, and may be between 1.1, 1.05, 1.0, 0.95, 0.9, 0.85, 0.8, preferably between 1.05 and 0.95, is dosed in stoichiometric amounts to form a salt with the complex.

Further, the contrast agent of the present invention is selected from the meglumine salt of DOTA-gadolinium complex.

In some embodiments, the method of the invention comprises the step of adjusting the pH of the solution to facilitate stabilizing the complexes in the solution and obtaining a fixed ratio of the meglumine salt of the DOTA-gadolinium complex. The process of adjusting the pH of the solution is to avoid causing new inorganic salts and changing the conductivity of the solution.

In some embodiments, the pH of the solution is adjusted to a suitable value with meglumine. Further, a solution pH =7-9 (e.g. 7.0, 7.5, 8.0, 8.5 or 9.0) may achieve the object of the invention.

In an alternative embodiment, the method of preparing a contrast agent of the present invention comprises:

a) Preparing a liquid composition comprising: a complex of macrocyclic chelate with a lanthanide, and meglumine, wherein the macrocyclic chelate/lanthanide molar ratio (mol/mol) is below 1.2, the macrocyclic chelate/meglumine molar ratio (mol/mol) is below 1.2,

b) Treating the liquid composition of step a) with a cationic resin selected from Relite CNS,

c) Treating the solution resulting from step b) with an anionic resin selected from Relite3As, preferably resulting in a solution pH = 2-5,

d) The pH value of the solution is adjusted, and the pH =7-9 is preferably adjusted by meglumine.

Further, the method also comprises an intermediate step c-1) between steps c and d), said step c-1) comprising treating the solution resulting from step c) with a resin of a cationic resin mixed with an anionic resin.

Further, the method also comprises a drying step in order to obtain a contrast agent solid, avoiding the drawback of the documents CN101977633A et al that do not allow to precisely detect the content of free gadolinium and free macrocyclic ligands. The drying mode comprises freeze drying or low-temperature spray drying, and the spray drying is preferably low-temperature electrostatic spray drying.

The content of chloride ions (C) in the contrast agent obtained by the method of the invention _Cl ) Less than 100ppm, and in some embodiments, chloride ion content (C) _Cl ) Less than or equal to 90ppm, 80ppm, 70ppm, 60ppm, 50ppm, 40ppm, 30ppm, 20ppm or 10ppm. In some embodiments, the chloride ion content may reflect the metal ion content in solution, such as sodium ions, potassium ions, or other alkaline earth metals.

Further, the free gadolinium content of the contrast agent obtained by the method of the present invention is less than 130ppm, and may be 130ppm, 120ppm, 100ppm, 90ppm, 80ppm, 70ppm, 60ppm, 50ppm, 40ppm, 30ppm, 20ppm, 10ppm or less.

The content of free macrocyclic chelate in the contrast agent obtained by the method of the present invention is less than 500ppm, and may be 500ppm, 400ppm, 300ppm, 200ppm, 100ppm, 50ppm or less.

The invention also provides a pharmaceutical formulation comprising the contrast agent obtained by the method and water.

Detailed description of the invention

The content or purity of the substance is determined by HPLC, and the detection method is as follows:

a Waters 2695Alliance liquid chromatograph or Agilent 1200 liquid chromatograph;

octadecylsilane chemically bonded silica is used as a filling agent; and 0.2% sodium phosphate and acetonitrile are respectively used as an A mobile phase and a B mobile phase for gradient elution, and the detection wavelength is 196nm.

The salt content determination in the present invention can be carried out by means of HPLC, and the retention time of the salt is approximately 1.9min. And the content data of the salt in the sample can be quantitatively obtained by utilizing a silver nitrate titration mode and through simple mathematical calculation. The silver nitrate titration method is known or ascertainable by those skilled in the art and can also be found in analytical chemistry, incorporated by Liaoli et al (Proc. Huazhong university of science, 2015.8.).

The retention time in the meglumine gadotetate HPLC according to the invention is about 9.963min.

The solvent dosage is calculated by volume unit, and the solid sample dosage is calculated by mass unit.

The method for determining the free gadolinium comprises the following steps:

accurately weighing 7.6g of the product, placing the product in a 250ml conical flask, adding water to dissolve the product, adjusting the pH value to 5.0-7.5, using pyridine and xylenol orange solution to make the solution become red, and using ethylene diamine tetraacetic acid titration solution to titrate the solution until the solution becomes yellow.

If there is free gadolinium in the sample, the calculation is performed according to the following formula:

wherein: v is the volume of titration consumed (ml); cs is the concentration (mol/L) of the ethylene diamine tetraacetic acid disodium titrate solution;

m is the weight (g) of the meglumine gadotetate sample;

the quality standard specifies that the content of gadoteric acid meglumine is as follows: the amount of free gadolinium is not more than 0.013% calculated as anhydride.

The use of resins in the present invention is after activation, which is well known or can be confirmed by those skilled in the art. For example, relite CNS resin is sequentially soaked in purified water, washed with 5% hydrochloric acid solution, and washed with purified water until the effluent pH is no greater than 7 and the conductivity is no greater than 10 μ/cm.

The freeze drying of the invention is divided into the following three stages: 1) Pre-freezing period: putting the sample into a freeze drying box, reducing the temperature to-40 ℃, preserving the heat for 6-8 hours, and starting a vacuum pump; 2) A sublimation period: the temperature of the heat conducting oil inlet is increased to-25 to-15 ℃, the heat is preserved for 6 to 8 hours, and the vacuum degree is kept between 150 and 200 mu bar; raising the temperature to-15-0 ℃, preserving the heat for 7-10 hours until the ice line disappears, and keeping the vacuum degree at 150-200 μ bar; 3) And (3) drying period: raising the temperature to 0-20 ℃, preserving the heat for 6-9 hours, and keeping the vacuum degree at 100-150 μ bar; the temperature is raised to 25 to 45 ℃, the temperature is kept for 20 to 30 hours, and the vacuum degree is kept between 100 and 150 mu bar.

The agents useful in the present invention are commercially available.

Drawings

FIG. 1: HPLC spectrogram of the finished product of meglumine gadotetate.

Detailed Description

The present invention will be explained in more detail with reference to examples, which are provided only for illustrating the technical solutions of the present invention and the spirit and scope of the present invention are not limited thereto.

Example 1

Adding 11.8kg of chloroacetic acid and 12L of purified water into a 100L reaction kettle, stirring and dissolving, adding 15L of water in which 5kg of sodium hydroxide is dissolved under ice bath, suspending 3.2kg of cycleanine in 6L of water, adding into the reaction, heating to 80-85 ℃, dropwise adding 6L of water in which 5.2kg of sodium hydroxide is dissolved, controlling the pH of a reaction system to be 10-11, reacting overnight, cooling to room temperature, dropwise adding 10.4L of concentrated hydrochloric acid, adjusting the pH to 2-2.5, stirring and crystallizing, filtering and collecting a filter cake, and drying to obtain 7.5kg of a DOTA crude product.

7.5kg of DOTA crude product and 18kg of purified water are added into a 50L reaction kettle, heated, stirred and dissolved, cooled, crystallized, filtered, washed and dried to obtain 6.21kg of DOTA, wherein the yield is 82.7 percent, and the content of salt is 2 percent.

Example 2:

5.1kg of DOTA obtained in example 1 was added to 50L of purified water, and after dissolving the mixture by heating with stirring at 40 to 50 ℃, meglumine (2.5 kg) and gadolinium oxide (2.33 kg) were added to the solution at pH =7 to 9, and the mixture was reacted by heating for 3 hours, cooled and filtered. Through inspection, the content of gadoteric acid in the crude solution of the meglumine gadoterate is 76 percent, and the content of the meglumine is 26 percent. Sequentially passing through a resin bed I filled with cationic resin Relite CNS, a resin bed II filled with anionic resin Relite3As and a resin bed III mixed and filled with anionic resin Relite3As and cationic resin Relite CNS to obtain the gadoteric acid meglumine solution with pH = 2-5, adjusting the pH =7-9 with meglumine, and testing, wherein the content of gadoteric acid in the gadoteric acid meglumine solution is 75%, the content of meglumine is 25.5%, the content of unknown single impurity is 0.008%, and the total impurity is 0.03%. And (3) carrying out filter pressing on the concentrated solution into a refined bag, subpackaging the refined bag into a tray, and freeze-drying the refined bag in a freeze dryer for 48 to 56 hours to obtain the meglumine gadotetate solid with the water content of 5 percent, the yield of 82 percent and the total yield of 65 percent in three steps.

Example 3: purification process of meglumine gadotetate crude product

Adding 57.1g of DOTA prepared by the method of example 1 into 500ml of purified water, heating and stirring the mixture at 40-50 ℃ to dissolve the DOTA, respectively adding meglumine (28 g) and gadolinium oxide (26 g), controlling the pH of the solution to be =7-9, heating the solution for reaction for 3 hours, cooling the solution and filtering the solution for later use;

taking a proper amount of the crude solution of the meglumine gadotetate, sequentially passing through cationic resin-anionic resin and/or macroporous adsorption resin, investigating the purification effect of different resins on the meglumine gadotetate, optimizing purification process parameters, taking a filtrate, detecting by HPLC, and recording data as shown in Table 1:

TABLE 1

Note:

a, selecting a resin bed from a mixture of macroporous adsorption resin, weak base or weak acid resin;

b, wherein the content of triacid impurity, 1,4,7, 10-tetraazacyclododecane-1, 4, 7-triacetic acid, is less than 0.01 percent;

c, after freeze-drying, detecting that the content of free gadolinium in the sample is higher than 0.05%, and numbering according to the first method of appendix VIII H of the second part of the 2010 edition of Chinese pharmacopoeia: the heavy metal content of GTSPA-ZJS is less than 0.01 percent;

the HPLC detection spectrum of the sample is shown in FIG. 1.

And (4) conclusion:

the macroporous adsorption resin can not be used for purifying a meglumine gadotetate sample, meanwhile, although the strong acid/strong base resin has a certain purification effect on the sample, the strong acid/strong base resin has strong adsorption on the resin and is difficult to analyze, so that new impurities are introduced into the sample to be purified or the purified sample, and in addition, the content of free gadolinium in the sample purified by the strong acid/strong base resin is easy to exceed the standard, and the possibility of strong adsorption of the resin is guessed.

Claims

1. A method of preparing a contrast agent comprising the steps of:

a) Preparing a liquid composition comprising: a complex of macrocyclic chelate DOTA with gadolinium, and meglumine, wherein the macrocyclic chelate/gadolinium molar ratio (mol/mol) is below 1.2, the macrocyclic chelate/meglumine molar ratio (mol/mol) is below 1.2,

b) Treating the liquid composition of step a) with a cationic resin, relite CNS,

c) Treating the solution resulting from step b) with the anionic resin Relite3As,

c-1) treating the solution produced in step c) with a resin of a mixture of cationic resin Relite CNS and anionic resin Relite3As to give a solution pH =2 to 5,

d) Adjusting the pH of the solution to be 7 to 9 by using meglumine.

2. The method of claim 1, wherein the contrast agent is selected from the meglumine salt of DOTA-gadolinium complex.

3. The method of claim 1, further comprising a drying step, wherein the drying means comprises freeze drying or low temperature spray drying.

4. The method of claim 3, wherein the spray drying is low temperature electrostatic spray drying.