阅读说明：本技术 一种钆布醇的精制方法 (Gadobutrol refining method ) 是由 范敏华 朱逸凡 周胜军 吴族悌 施海峰 陆翠军 聂良邓 于 2021-06-22 设计创作，主要内容包括：本发明提供了一种钆布醇的精制备工艺,钆布醇粗品进行脱色,滴加NH4OH溶液,置于透析袋超声或树脂层析,加入氢气,持续搅拌,置换烧瓶内的纯水,检测PH和电导率,冷冻干燥获得纯净钆布醇,试验操作调节温和,获得的产品纯度可达99.9%,游离钆含量＜0.01,以KIM-1作为肾损伤参数检测,本发明产品可以降低造影剂肾毒性,甚至无肾毒性。(The invention provides a gadobutrol refining preparation process, wherein a gadobutrol crude product is decolorized, an NH4OH solution is dripped, the gadobutrol crude product is placed in a dialysis bag for ultrasonic or resin chromatography, hydrogen is added, the stirring is continued, pure water in a flask is replaced, the PH and the conductivity are detected, pure gadobutrol is obtained by freeze drying, the experimental operation is mild in regulation, the purity of the obtained product can reach 99.9 percent, the content of free gadolinium is less than 0.01, and KIM-1 is used as a kidney injury parameter for detection.)

1. A refining method of gadobutrol with purity not less than 99.8 percent comprises the following steps:

dissolving gadobutrol crude product in pure water, decolorizing with activated carbon, dripping NH4OH solution, adjusting pH to 6-6.8, rotary evaporating the filtrate to remove solvent, adding pure water to dissolve again, placing the filtrate in dialysis bag (SpectrumLabs), immersing the dialysis bag in water in a glass flask, introducing a proper amount of hydrogen, continuously stirring for 1-24h, monitoring the change of PH in the beaker water by a precise pH monitor at different time, stirring until the pH is stable, replacing the water in the glass flask, adding a small amount of ethanol into a dialysis bag, carrying out intermittent ultrasound, replacing the water in the flask again after continuously stirring, stirring overnight until the pH in the flask is stable and the conductivity is less than 20 mu s, taking out the dialysis bag, filtering to obtain a primary precipitate, placing the primary precipitate on a heating plate to evaporate a solvent, placing in a flat-bottom plate, refrigerating in a refrigerator, placing in a freeze drying box, and drying for 12-18 h.

2. A refining method of gadobutrol with purity not less than 99.8 percent comprises the following steps:

taking a gadobutrol crude product, adding pure water for dissolving, dropwise adding an NH4OH solution after decoloring treatment by activated carbon, adding pure water for dissolving again after rotary evaporation of a solvent, passing through a resin column SK1B for chromatography, performing gradient elution, placing filtrate in a dialysis bag, immersing the dialysis bag in water in a glass flask, introducing a proper amount of hydrogen, continuously stirring for 1-24h, monitoring the change of PH in the beaker water by a precise PH monitor at different time, stirring for 24h until the PH is stable, taking out the dialysis bag, replacing water in the flask, adding ethanol into the dialysis bag, performing digital ultrasound, performing intermittent ultrasound for 30min, continuously stirring overnight, filtering until the water conductivity in the flask is less than 20 mu s, filtering to obtain a primary precipitate, filtering, and removing the solvent by rotary evaporation.

3. A refining method of gadobutrol with purity not less than 99.8 percent comprises the following steps:

dissolving a gadobutrol crude product by adding pure water, decoloring by using activated carbon, dropwise adding an NH4OH solution, performing rotary evaporation on a solvent, adding the pure water for re-dissolving, adjusting the pH value to 6-6.8, performing digital ultrasound, introducing a proper amount of hydrogen, continuously stirring for 1-24 hours, monitoring the change of the pH value in beaker water by using a precise pH monitor at different time until the pH value is stable, purifying by using an Amberchrome CG161M resin column, performing gradient elution by using water and ethanol, continuously stirring and filtering the obtained filtrate to obtain a primary precipitate, evaporating the precipitate to be nearly dry by using a heating plate, placing the precipitate in a flat pan for refrigeration, and performing freeze drying to obtain white powder.

4. A refining method of gadobutrol with purity not less than 99.8 percent comprises the following steps:

dissolving a gadobutrol crude product with pure water, decoloring with active carbon, dropwise adding an NH4OH solution, performing rotary evaporation on the obtained filtrate to remove a solvent, adding the pure water to dissolve again, purifying with an Amberchrome CG161M resin column, performing gradient elution with water and ethanol, placing the obtained filtrate in a dialysis bag, adding a small amount of ethanol, immersing the dialysis bag in water in a glass flask, performing intermittent ultrasound, introducing a proper amount of hydrogen, continuing stirring, replacing flask water, stirring overnight, monitoring the change of PH in the beaker water by a precise PH monitor at different time until the PH is stable, wherein the water conductivity is less than 20 mus, and filtering to obtain a primary precipitate.

5. Placing the primary precipitate on a heating plate, evaporating the solvent, placing the primary precipitate in a flat chassis for refrigeration, and then freeze-drying to obtain white powder gadobutrol, wherein the purity is 99.9% by detection.

6. The method of claims 1-2, 4, wherein: the dialysis bag model was 500Da with a molecular weight cut-off (MWCO) of 500 Da.

7. The method of claims 1, 3-4, wherein: the ultrasonic treatment is carried out by using a Branson digital ultrasonic instrument to carry out ultrasonic treatment for 30s at 10% micro amplitude and then standing for 1 minute for intermittent ultrasonic treatment, wherein the ultrasonic treatment time is 30 min.

8. The method of claims 1, 3-4, wherein: the freeze drying method comprises placing the primary precipitate in a flat chassis, keeping the height of about 2cm, refrigerating for 12h in a refrigerator, placing in a freeze drying device at-40-50 deg.C, keeping the pressure of the drying box at 10-13Pa, pre-drying for 2-5h, reducing the pressure of the drying box to 1Pa, vacuum drying for 2h, slowly heating to 35 deg.C, and continuously drying for 8-10h

The method of claims 1, 3-4, wherein: the freeze drying method comprises the steps of placing the primary precipitate in a flat chassis and keeping the height of 2cm, refrigerating for 12 hours in a refrigerator, placing in a freeze drying device at 50 ℃ below zero, keeping the pressure of a drying box at 12Pa, pre-drying for 3 hours, reducing the pressure of the drying box to 1Pa, drying for 2 hours in vacuum, slowly heating to 35 ℃, and continuously drying for 9 hours.

9. A process according to claims 1-4, characterized in that gadobutrol obtained by purification has a purity of 99.8% or more and a free gadolinium content of < 0.01%.

Technical Field

The invention relates to the field of a preparation method of gadobutrol, and comprises a method for refining a gadobutrol crude product to obtain a high-purity product.

Background

Gadobutrol is a gadolinium-containing contrast agent for nuclear spin tomography for contrast enhancement in cranial and spine Magnetic Resonance Tomography (MRT). Corrugol is a nonionic complex of gadolinium and the macrocyclic ligand 10- (2, 3 dihydroxy-1- (hydroxymethyl) propyl) -1, 4, 7, 10-tetraazacyclododecane-1, 4, 7-triacetic acid (butrol). Usually sold as a 1 molar aqueous solution, the main methods of preparation today are:

because the reaction steps of gadobutrol are more, 4 amino groups on cyclen can react, protection and deprotection are needed, so that the by-product of the product is more, wherein the ring-opening reaction conditions are severe, various impurities are easy to generate, and the purity requirement of the contrast agent is extremely high, so that multi-step purification of an intermediate and a finished product is needed, and the process is extremely complicated.

The refining method for improving the purity of gadobutrol mainly comprises the modes of intermediate purification and product purification, wherein the method comprises the steps of adopting ion exchange resin, crystallizing and concentrating mother liquor, then recrystallizing, wherein the subsequent processes all need the operation of concentration and dehydration, the needed ion resin needs pretreatment and activation, and a plurality of resins and crystallization are repeated, so that the energy consumption and the time consumption are both long.

For example, CN105037288B discloses a method for preparing high-purity buconazole, which comprises purifying crude aqueous solution of buconazole by passing through ion exchange resin for several times, and then purifying by recrystallization with mixed solvent, so as to increase the purity of buconazole to more than 99.5%.

CN103547573B through specially controlled crystallization conditions, selecting specific water content, preparing high-purity gadobutrol, reducing lipophilic impurities (such as D03A) and strong hydrophilic impurities, and carrying out acid-alkali-acid multiple ion column chromatography on the crude product, and then carrying out complex condition crystallization to obtain pure gadobutrol with specific water content.

The above purification process is cumbersome, requires strict control of conditions, prior art needs to be improved in terms of convenience, yield and efficiency of the purification process, and additionally more purified compounds can reduce the required dose of paramagnetic contrast agents and possibly shorten the acquisition time of the imaging process.

Because the free amount of Gd obviously influences the toxic and side effects of the medicine, gadolinium used as a heavy metal may form damage which is difficult to reverse in the kidney brain, the contrast effect is ensured, the dosage is reduced as much as possible, the imaging time is shortened, and the toxic and side effect risk can be reduced. In order to increase the chemical combination relaxation rate, the prior art generally adopts MRI to load on a macromolecular material, the larger the molecular structure is, the larger the steric hindrance is, the rotational motion of the molecule is delayed, and the rotation related time is increased, so that the R1 is greatly increased.

However, the large molecule Gd³⁺The contrast agent has increased circulation time in vivo and gradually releases Gd³⁺The probability of (a) is increased, which leads to serious toxicity problems, such as kidney damage, fibrosis of the renal system, etc., and brain deposits seriously affect the nervous system.

Disclosure of Invention

According to the invention, by improving the purification method and applying the membrane permeation combined with the freeze drying process, relatively pure gadobutrol is obtained, the damage to the kidney can be obviously reduced, and even no renal toxicity is detected.

The method comprises the following specific steps:

taking a gadobutrol crude product, adding pure water for dissolution, and dropwise adding NH after active carbon decoloration treatment₄Adjusting the pH of OH solution to 6-6.8, performing rotary evaporation on the obtained filtrate to remove the solvent, adding purified water to dissolve again, optionally adding the solution into cationic resin, placing the filtrate into a dialysis bag (SpectrumLabs), immersing the dialysis bag in water in a glass flask, introducing a proper amount of hydrogen, continuously stirring for 1-24h, and monitoring the change of the pH in the beaker water by a precision pH monitor at different times. Stirring for 24h until the pH value is stable,taking out the dialysis bag, adding a small amount of 50% ethanol, performing ultrasonic treatment to replace water in the glass flask, continuously stirring the dialysis bag overnight until the pH value in the flask is stable, taking out the dialysis bag, filtering to obtain a primary precipitate, placing the primary precipitate in a flat pan, refrigerating in a refrigerator, placing in a freeze drying oven, and drying for 12-18 h.

Or taking the gadobutrol crude product, adding pure water for dissolution, and dripping NH after the activated carbon is decolored₄Adjusting the pH of OH solution to 6-6.8, performing rotary evaporation on the obtained filtrate to remove solvent, adding purified water to dissolve again, placing the filtrate in a dialysis bag (SpectrumLabs), immersing the dialysis bag in water in a glass flask, introducing a proper amount of hydrogen, continuously stirring for 1-24h, monitoring the change of the pH in the water in the beaker through a precision pH monitor at different time, stirring until the pH is stable, replacing the water in the glass flask, adding 10-20ml of a small amount of ethanol into the dialysis bag, performing intermittent ultrasound, continuously stirring, replacing the water in the flask again, stirring overnight until the pH in the flask is stable and the conductivity is less than 20 mu s, taking out the dialysis bag, filtering to obtain primary precipitate, placing the primary precipitate in a heating plate to evaporate the solvent, placing the primary precipitate in a flat-bottom plate refrigerator, placing the primary precipitate in a freeze drying box, and drying for 12-18h to obtain the product

Or, taking the crude product of gadobutrol, adding pure water for dissolution, and dripping NH after the activated carbon is decolored₄Dissolving OH solution in purified water after rotary evaporation of a solvent, performing chromatography through a resin column SK1B, performing gradient elution, placing filtrate in a dialysis bag, immersing the dialysis bag in water in a glass flask, introducing a proper amount of hydrogen, continuously stirring for 1-24h, monitoring the change of PH in beaker water through a precise PH monitor at different time, stirring for 24h until the PH is stable, taking out the dialysis bag, replacing the water in the flask, adding ethanol in the dialysis bag, performing digital ultrasound, performing intermittent ultrasound for 30min, continuously stirring overnight until the water conductivity in the flask is less than 20 mu s, filtering to obtain primary precipitate, and filtering to remove the solvent through rotary evaporation.

Or, taking the crude product of gadobutrol, adding pure water for dissolution, and dripping NH after the activated carbon is decolored₄Dissolving OH solution in purified water after rotary evaporation of solvent, adjusting pH to 6-6.8, performing digital ultrasonic treatment while introducing appropriate amount of hydrogen gas, stirring for 1-24 hr, and monitoring pH in beaker water with precision pH monitor at different timeChanging the pH value to be stable, wherein the water conductivity is less than 20 mu s, purifying by an Amberchrome CG161M resin column, carrying out gradient elution by water and ethanol, continuously stirring and filtering the obtained filtrate to obtain a primary precipitate, evaporating the precipitate to be nearly dry by a heating plate, placing the precipitate in a flat pan for refrigeration and freeze drying to obtain white powder, and detecting the purity of gadobutrol by HPLC (high performance liquid chromatography) to be 99.9 percent, wherein the content of single impurities is less than 0.02 percent, and the content of free gadolinium is less than 0.01 percent.

Or taking a gadobutrol crude product, dissolving with pure water, decoloring with active carbon, and then dropwise adding NH₄And (2) carrying out OH solution, carrying out rotary evaporation on the obtained filtrate to remove the solvent, adding purified water to dissolve again, purifying by an Amberchrome CG161M resin column, carrying out gradient elution by using water and ethanol, placing the obtained filtrate in a dialysis bag, adding a small amount of ethanol, immersing the dialysis bag in water in a glass flask, carrying out intermittent ultrasound, introducing a proper amount of hydrogen simultaneously, continuing stirring, replacing flask water, stirring overnight, monitoring the change of PH in the beaker water by a precise PH monitor at different time until the PH is stable, wherein the water conductivity is less than 20 mu s, and filtering to obtain a primary precipitate. Placing the primary precipitate on a heating plate, evaporating the solvent to dryness, placing the primary precipitate in a flat chassis for refrigeration, and then freeze-drying to obtain white powder gadobutrol, wherein the purity is 99.9% by HPLC detection.

Wherein the type of the dialysis bag is 500Da, the molecular weight cut-off (MWCO) is 500Da, the time for introducing hydrogen is preferably 1-2h, more preferably 2h, the Branson digital ultrasound is preferably performed for 30s with 10% micro amplitude, then the mixture is kept stand for 1min for intermittent ultrasound, and the ultrasound is performed for 20-120min, more preferably 30 min; the small amount of ethanol is 10-20ml of 50% ethanol.

Preferably, the primary precipitate is placed in a flat chassis and kept at a height of about 2cm, the chassis is refrigerated for 12 hours in a refrigerator and then placed in a freeze drying device at the temperature of minus 40 to 50 ℃, the pressure of a drying box is kept at 10 to 13Pa, after pre-drying is carried out for 2 to 5 hours, the drying box is depressurized to 1Pa, vacuum drying is carried out for 2 hours, the temperature is slowly raised to 35 ℃, and drying is continuously carried out for 8 to 10 hours.

More preferably, the primary precipitate is placed in a flat chassis and kept at the height of 2cm, the chassis is refrigerated for 12h in a refrigerator and then placed in a freeze drying device at 50 ℃ below zero, the pressure of a drying oven is kept at 12Pa, after pre-drying is carried out for 3h, the pressure of the drying oven is reduced to 1Pa, the drying oven is dried in vacuum for 2h, the temperature is slowly increased to 35 ℃, and the drying is continuously carried out for 9 h.

The purity of the gadobutrol obtained by purification of the invention is more than or equal to 99.8 percent, and the content of free gadolinium is less than 0.01 percent.

The hydrogen gas inlet amount can be selected to be 0.2m3/h, the ultrasonic frequency can be 40KHZ, and the power is 150W.

Comparative tests were carried out on the purified gadobutrol according to the invention and on the commercially available gadobutrol as well as on the gadobutrol purified by the method of CN105037288B, CN103547573B (examples 1, 2).

The invention has the beneficial effects that:

1) the invention tries an unconventional purification method, improves the product purity, degrades organic impurities and reduces the generation of byproducts under specific conditions.

2) The steps of purification and the like are simplified, and the preparation condition is mild and easy to repeat.

3) The renal toxicity of the medicine is obviously reduced.

Drawings

FIG. 1: the prepared gadobutrol LC-MC map

FIG. 2 HPLC chromatogram of refined gadobutrol

Detailed Description

Example 1(CN105037288 preparation method)

Adding 1kg of water into 700g of gadobutrol crude product, dissolving the solution in the 717 resin, slowly adding 18kg of pure water, measuring the electric conductivity by using a conductivity meter, slowly adding 2M ammonia water to flow through the resin when the electric conductivity is less than or equal to 30 mu s, evaporating the solution containing the product under reduced pressure, adding the pure water to dissolve the solution after evaporation, cooling the solution to 26 ℃, adding the cationic resin IR120, adjusting the pH to 4, filtering, adding 57g of activated carbon into the filtrate, heating the filtrate, carrying out reflux decoloration by using a knife, and carrying out hot filtration and evaporation to dryness; adding pure water with the mass of 5 times that of the product obtained by the treatment in the step, heating to 30 ℃ to completely dissolve the product to obtain a clear solution, adding isopropanol with the volume of 10 times that of the clear solution, slowly heating to 50 ℃, keeping the temperature for crystallization for 10 hours, cooling to 30 ℃, filtering and drying to obtain 460g of gadobutrol, wherein the purity is 99.5 percent (HPLC), the content of single impurities is less than 0.037 percent, and the content of free gadolinium is less than 0.02 percent.

Example 2 (preparation by CN 103547573B)

120kg of gadobutrol crude were dissolved in 1200kg of water and initially pumped onto a column containing an acidic ion exchanger (AMBERLITE IRC 50). The eluent was pumped directly onto the column of basic ion exchanger (IRA67) and then pumped back onto the acidic ion exchanger (and so on). The solution was recirculated until a conductivity limit of <20 μ s/cm was reached. The solution was transferred to a thin-layer evaporator and carefully concentrated at 50 mbar.

And (3) final crystallization: 16kg of activated carbon NORIT SX PLUS were added to 324kg of gadobutrol (19. l% -20.9% strength solution in water) (conductivity 20. mu.S) and the mixture was stirred for 60 minutes at 20 ℃. The activated carbon was filtered off and washed twice with water. The filtrate solution containing the product was then filtered through a sterile filter rod and concentrated under reduced pressure at a jacket temperature of 80 ℃. The jacket temperature was then increased to 75 ℃ and in the first step IOOkg of alcohol was metered in, then the jacket temperature was increased to 98 ℃ (internal temperature >75 ℃) and a further 1360kg of alcohol was added, so that the internal temperature was not lower than 72 ℃ (the total time of metering in was about 120 minutes). At this point, the water content of the solution was measured according to the Karl-Fischer method. Ideally, this value should be between 10% and 12%. If the value is too high or too low, it is adjusted to exactly 11% by adding water or alcohol (in small portions). Once the desired water content was reached, the mixture was heated under reflux for 120 minutes. The mixture was cooled to 20 ℃, the product was separated using a centrifuge or a pressure suction filter, and the filter cake was washed with ethanol. The product was then dried under reduced pressure (jacket temperature 55 ℃) until an internal temperature >53 ℃ was reached. The product was then filled into aluminum-coated PE bags. A colorless crystalline powder was obtained. The detection purity is 99.7 percent (HPLC), the content of single impurity is less than 0.03 percent, and the content of free gadolinium is less than 0.01 percent.

Example 3:

taking 80g of a gadobutrol crude product, adding 800ml of pure water for dissolving, adding 500g of activated carbon for decoloring, dropwise adding 100ml of 0.2% NH4OH solution, rotationally evaporating the obtained filtrate to remove the solvent, adding the pure water for dissolving again, adjusting the pH value to 6-6.8, placing the filtrate in a dialysis bag (Spectrum labs) with the molecular weight cut-off (MWCO) of 500Da, immersing the dialysis bag in water in a 2L glass flask, introducing a proper amount of hydrogen for 2h, continuously stirring for 12h, and monitoring the change of the pH value in the beaker water by a precision pH monitor at different times. Stirring for 24h until the pH is stable, taking out the dialysis bag, replacing water in the flask with 2L, placing into the dialysis bag, stirring, adding a small amount of ethanol (10-20 ml of 50% ethanol), performing intermittent ultrasonic treatment with 10% microamplitude for 30s, stopping for 1min, performing ultrasonic treatment for 30s, stopping for 1min, repeating for 30min, stirring for 12h, replacing water in the flask again, stirring overnight until the pH in the soaking solution (flask water) in the dialysis bag is stable, and simultaneously the water conductivity in the flask is less than 20 μ s, taking out the dialysis bag, filtering to obtain primary precipitate, placing the primary precipitate on a heating plate, evaporating to a nearly dry state (i.e. evaporating the solvent), placing the primary precipitate in a flat bottom plate for 2cm, refrigerating for 12h, placing in a freezing and drying device at 50 ℃ below zero, keeping the pressure of the drying box at 12Pa, pre-drying for 3h, and (3) reducing the pressure of the drying oven to 1pa, drying in vacuum for 2h, slowly raising the temperature to 35 ℃, and continuing to dry for 9 h. A white powder of gadobutrol is obtained (detection see figure 1). The detection purity is 99.8 percent (HPLC), the content of single impurity is less than 0.025 percent, and the content of free gadolinium is less than 0.01 percent.

Example 4:

taking 80g of a gadobutrol crude product, adding 800ml of pure water for dissolving, adding 500g of activated carbon for decoloring, dropwise adding 100ml of 0.2% NH4OH solution, performing rotary evaporation on the obtained filtrate to remove the solvent, adding the pure water for dissolving again, passing through cationic resin SK1B (performing gradient elution with water/ethanol), placing the filtrate in a dialysis bag (SpectrumLabs) with molecular weight cut-off (MWCO) of 500Da, immersing the dialysis bag in water in a 2L glass flask, introducing a proper amount of hydrogen for 2h, continuously stirring for 12h, and monitoring the change of the pH in the beaker water by a precision pH monitor at different times. Stirring for 24h until the pH is stable, taking out the dialysis bag, replacing water in the flask, filling 2L, adding a small amount of ethanol (10-20 ml of 50% ethanol), intermittently performing Branson digital ultrasound with 10% microscale amplitude for 30s, stopping the ultrasound for 1min, performing ultrasound for 30s, stopping the ultrasound for 1min, repeating the steps for 30min, continuing stirring for 12h, replacing water in the flask, continuously stirring overnight until the water conductivity in the flask is less than 20 mus, and filtering to obtain a primary precipitate. The primary precipitate was rotary evaporated to remove the solvent to give gadobutrol as a white solid. The purity is 99.8 percent (HPLC), the content of single impurity is less than 0.03 percent, and the content of free gadolinium is less than 0.01 percent.

Example 5:

dissolving 80g of gadobutrol crude product in 800ml of pure water, adding 500g of activated carbon for decolorization, dropwise adding 100ml of 0.2% NH4OH solution, rotationally evaporating the obtained filtrate to remove the solvent, adding the pure water for redissolution, adjusting the pH value to 6-6.8, stopping intermittent ultrasonic treatment for 1 minute after ultrasonic treatment for 30 seconds by Branson digital ultrasonic treatment at 10% microscale amplitude, stopping intermittent ultrasonic treatment for 30 minutes, introducing a proper amount of hydrogen, continuously stirring for 12 hours, monitoring the change of the pH value in beaker water by a precise pH monitor at different times until the pH value is stable, controlling the water conductivity to be less than 20 mu s, purifying by an Amberchrome CG161M resin column (water/ethanol elution), continuously stirring and filtering the obtained filtrate to obtain a primary precipitate, placing the primary precipitate on a heating plate, evaporating to be close to a dry state, placing the primary precipitate in a flat bottom plate for 2cm, placing the primary precipitate in a freeze-drying device at 50 ℃ after refrigerating for 12 hours in a refrigerator, keeping the pressure of the drying box at 12Pa, after pre-drying for 3h, reducing the pressure of the drying oven to 1pa, drying in vacuum for 2h, slowly raising the temperature to 35 ℃, and continuing to dry for 9 h. White powder gadobutrol is obtained, the purity is 99.9 percent (HPLC), the content of single impurity is less than 0.02 percent, and the content of free gadolinium is less than 0.01 percent (see figure 2).

Example 6:

taking 80g of gadobutrol crude product, adding 800ml of pure water for dissolving, adding 500g of activated carbon for decoloring, dropwise adding 100ml of 0.2% NH4OH solution, rotationally evaporating the obtained filtrate to remove the solvent, adding the pure water for dissolving again, purifying by an Amberchrome CG161M resin column (water/ethanol elution), placing the obtained filtrate in a dialysis bag (SpectrumLabs) with molecular weight cut-off (MWCO) of 500Da, adding a small amount of ethanol (10-20 ml of 50% ethanol), immersing the dialysis bag in water of a 2L glass flask, stopping ultrasonic wave for 1 minute after intermittent ultrasonic wave for 30 seconds with 10% microscale amplitude by Branson digital ultrasonic wave, stopping ultrasonic wave for 30 seconds, stopping ultrasonic wave after reciprocating for 30 minutes, simultaneously introducing a proper amount of hydrogen for 2 hours, continuing stirring for 12 hours, replacing the water flask for 2L, stirring overnight, monitoring the change of PH in beaker water by a precision pH monitor at different times until the PH is stable, and the water conductivity is less than 20 mus, filtering to obtain a primary precipitate. Placing the primary precipitate on a heating plate, evaporating to a state close to dry, namely evaporating the solvent, placing the solvent in a flat chassis, keeping the height of the solvent at 2cm, refrigerating for 12h in a refrigerator, placing the refrigerated precipitate in a freeze drying device at 50 ℃ below zero, keeping the pressure of a drying oven at 12Pa, pre-drying for 3h, reducing the pressure of the drying oven to 1Pa, drying for 2h in vacuum, slowly heating to 35 ℃, and continuing to dry for 9 h. The white powder gadobutrol is obtained, the purity is 99.9 percent (HPLC) through detection, the content of single impurity is less than 0.02 percent, and the content of free gadolinium is less than 0.01 percent.

COMPARATIVE EXAMPLE 1 commercially available gadobutrol injection solution (15 ml: 9.0708g, Bayer Pharma AG)

Comparative example 2: Gd-DTPA (gadopentetate meglumine injection) (15 ml: 7.5g, BAYER PHARMA)

Test 1: nephrotoxicity assay

KIM-1 is an indicator of earlier change than phenotype in renal function injury detection, and as a type I transmembrane glycoprotein, it is hardly expressed in normal renal tissues, and is significantly increased in renal tissues with renal toxicity of murine contrast agents. The experiment adopts ELISA method, and 120 healthy mice are divided into 6 groups and respectively treated with Gd³⁺The concentration is 0.1mmol/kg dose tail vein injection, the samples of comparative examples 1 and 2 and examples 1-6 are taken before injection, 12h after injection and 24h after injection, urine is taken for detecting KIM-1 value, the numerical value obtained by each group of mice is averaged, and the kit is American R&The original urine detection kit produced by the company D; and detecting by using a full-automatic biochemical analyzer. Analysis was performed using SPSS20.0 statistical software, and differences between groups were compared using t-test with P<A difference of 0.05 is statistically significant. As shown in Table 1, the comparative differences among the three groups of the examples other than example 5 are statistically significant (P)<0.05)。

TABLE 1 index changes of renal injury before and after contrast media injection in mice

As can be seen from the results in Table 1, the Gd-DTPA gadolinium contrast agent of comparative example 2 has higher renal toxicity and does not exhibit a metabolic decline over time, may take longer to be excreted, and is more likely to cause renal injury. In other examples 1-6 where gadobutrol is refined, the product with lower free gadolinium content has better safety than the commercial product. The KIM-1 value of the product of example 5 was the lowest, with the three groups being nearly identical and decreasing to normal levels over time, which was considered to be the group of mice with virtually no kidney damage. Example 3 the KIM-1 value was also lower, but the rate of decrease over time was less than the other example products. Examples 3-6 product variations may be associated with different steps in their preparation and the sequential operation of the process, particularly the freeze-drying process.

The test results show that the product with higher purity is obtained by optimizing the preparation process, and simultaneously, due to the combined effect of the steps of ultrasonic chemical reaction, freeze-drying and the like, the reaction time is shortened, the yield is improved, the crystallization step is simplified, and the method can be related to cavitation and an intra-molecular linkage structure.

The above-described embodiments are not intended to limit the scope of the present invention, and those skilled in the art can make various modifications and applications of the present invention based on the above-described description.