CN115721739A - A kind of contrast agent and its application for pyelonephritis MRI - Google Patents

Abstract

The present invention provides a contrast agent for pyelonephritis MRI and its application. The contrast agent consists of 2-4 parts of 4-arm-amino-polyethylene glycol, 2-4 parts of gadopentetate meglumine, and phospholipid 80- 120 parts, 2-4 parts of N-acetylneuraminic acid, 5-10 parts of dextran, and water for injection. The present invention improves the formulation of the contrast agent, reduces the concentration of the molecular complex of paramagnetic metal gadolinium (Gd) in the contrast agent and increases its enrichment in the kidney tissue, thereby reducing the toxicity of Gd , and can improve the sensitivity of nuclear magnetic resonance imaging, which is beneficial to reduce the cost and reduce the side effects of the contrast agent.

Description

A kind of contrast agent and its application for pyelonephritis MRI

technical field

The invention belongs to the field of diagnostic reagents, in particular, the invention relates to a contrast agent for nuclear magnetic imaging of pyelonephritis and its application.

Background technique

Magnetic resonance imaging (MRI) produces detailed descriptions of human anatomy and pathology at high spatial resolution. To increase the diagnostic sensitivity and specificity of MRI, eg, for imaging of cancer, infection, neurological and cardiac disease, contrast material is often administered intravenously before and/or during imaging to improve the signal.

MRI imaging uses the disorderly small magnetic moments formed by hydrogen protons in various parts of the human body. Under the radio frequency magnetic field, different vibrations occur. The signal is transformed into the grayscale pixels of each slice, and the gradient magnetic fields GX, GY, and GZ are used to complete the spatial positions of different slices and hydrogen protons. The MRI signal intensity of water protons in human tissue is related to many factors (spin density NH, imaging volume parameter fV, longitudinal relaxation time T1, transverse relaxation time T2, and scanning time TE and TR), among which the two most important ones are imaging The parameters are relaxation times T1 and T2. Some compounds containing paramagnetic nuclei can be used to significantly change the T1 and T2 of the surrounding hydrogen nuclei to improve the contrast of imaging. Such paramagnetic substances are called contrast agents. The principle of its action is that the local magnetic field generated by the paramagnetic substance affects the relaxation rate of the adjacent measured nuclei such as water proton 1H (the process of dissipating the energy of the measured nucleus excited by radio frequency to a high energy state and returning to a low energy state rate) has an acceleration effect, so that the image signal of MRI that depends on the relaxation rate (1/T1 or 1/T2) is enhanced, resulting in an increase in the contrast and clarity of the image. According to this principle, when the paramagnetic metal chelate is used as a contrast agent, it is actually the paramagnetic metal ion in it, and the main function of the chelating agent is to make the paramagnetic metal ion form a stable, water-soluble chelate , reduce the toxicity of metal ions and make it easy to use.

The most common MRI contrast materials are based on molecular complexes containing the paramagnetic metal gadolinium (Gd). In the US, all nine FDA-approved MRI contrast agents are Gd-based. Gd has a strong "paramagnetism" that causes a local increase in MRI signal on T1-weighted images. However, Gd-based contrast agents can cause a rare but severely debilitating condition called nephrogenic systemic fibrosis (NSF), a syndrome involving widespread fibrosis of the skin, joints, eyes and internal organs. WHO and FDA have issued restrictions on the use of these agents in patients with renal insufficiency/failure, with the FDA prescribing a "black box" warning on all commercially available gadolinium-containing media. As a result, millions of patients in the United States, and many more worldwide, can no longer receive contrast material for MRI, severely limiting the detection and characterization of several diseases.

In order to solve the above technical problems, the Chinese authorized patent CN108743977B discloses the application of a porphyrin compound without heavy metal ions as a contrast agent in magnetic resonance imaging. The low sensitivity of magnetic resonance imaging leads to inconspicuous contrast between normal tissue and lesion in clinical observation. , difficult diagnosis, and the heavy metal ion-containing contrast agent is easy to increase the metabolic burden of the patient's liver and kidney. The invention injects porphyrin compounds without heavy metal ions, and uses chemical exchange saturation transfer magnetic resonance imaging technology to detect the signals of porphyrin compounds, and finally achieves a reduction background signal and improve the sensitivity of magnetic resonance imaging.

As another example, Chinese patent CN107087397B discloses that ascorbic acid or its pharmaceutically acceptable salt and co-formulated meglumine, glucose, galactose, fructose, lactose, maltose, sucrose and/or trehalose are used in the preparation of Use in medicine of a method of magnetic resonance imaging (MRI) images of a subject's body or body region, said method comprising: parenterally administering to said subject co-formulated ascorbic acid or its pharmaceutically an acceptable salt; and an image of said body or body region is then produced by MRI of the subject, whereby the co-formulated ascorbic acid or a pharmaceutically acceptable salt thereof enhances the MRI image.

Although the use of metal gadolinium (Gd) without heavy metal ions as a contrast agent in patients with renal insufficiency/failure has become a new direction. However, contrast agents without heavy metal ion gadolinium (Gd) still have problems such as insufficient contrast. Therefore, the object of the present invention is to provide a kind of contrast agent containing the molecular complex of paramagnetic metal gadolinium (Gd), by reducing the concentration of the molecular complex of paramagnetic metal gadolinium (Gd), increase its The enrichment of Gd can not only reduce the toxicity of Gd, but also improve the sensitivity of MRI.

Contents of the invention

The present invention mainly provides a contrast agent for nuclear magnetic imaging of pyelonephritis and its application. In order to realize the purpose of the present invention, it is planned to adopt the following technical solutions:

One aspect of the present invention relates to a contrast agent for MRI of pyelonephritis, characterized in that the contrast agent consists of 2-4 parts of 4-arm-amino-polyethylene glycol, 2-4 parts of gadopentetate meglumine, It is prepared by 80-120 parts of phospholipid, 2-4 parts of N-acetylneuraminic acid, 5-10 parts of dextran and water for injection.

In a preferred embodiment of the present invention, the nuclear magnetic resonance contrast agent consists of 2-3 parts of 4-arm-amino-polyethylene glycol, 2-3 parts of gadopentetate meglumine, 80-100 parts of phospholipids, N-acetyl It is prepared by 2-3 parts of neuraminic acid, 5-7 parts of dextran and water for injection.

In a preferred embodiment of the present invention, the phospholipid is egg yolk phospholipid and/or lecithin; preferably egg yolk phospholipid.

In a preferred embodiment of the present invention, the nuclear magnetic resonance contrast agent is a liposome preparation.

In another preferred embodiment of the present invention, the average particle diameter of the liposome preparation is 100-150 nm.

In another preferred embodiment of the present invention, the average particle diameter of the liposome preparation is 120-130 nm. By controlling the particle size of the liposome within the preferred range of the present invention, it is helpful to improve the contrast effect.

In a preferred embodiment of the present invention, the nuclear magnetic resonance contrast agent is prepared by the following steps:

(1) Preparation of liposomal nanoparticles: Weigh phospholipids, dextran, and 4-arm-amino-polyethylene glycol according to the formula, dissolve them in chloroform solution, stir them evenly, place them in a rotary evaporator, and rotate them in a water bath Form a film, add gadopentetate dimeglumine solution after vacuum drying to prepare a liposome emulsion, and obtain PEG amino-modified nuclear magnetic resonance contrast agent liposome nanoparticles by ultracentrifugation;

(2) Weigh the PEG amino-modified nuclear magnetic resonance contrast agent liposome nanoparticles prepared in step (1) and N-acetylneuraminic acid, and incubate together in water for injection at 20-30°C for 5-15min , to obtain the MRI contrast agent.

Another aspect of the present invention also relates to the application of the above nuclear magnetic resonance contrast agent in the preparation of a contrast agent for diagnosing renal tissue diseases.

In a preferred embodiment of the present invention, the renal tissue disease is pyelonephritis.

Beneficial effects of the present invention

The present invention improves the formulation of the contrast agent, reduces the concentration of the molecular complex of paramagnetic metal gadolinium (Gd) in the contrast agent and increases its enrichment in the kidney tissue, thereby reducing the toxicity of Gd , and can improve the sensitivity of nuclear magnetic resonance imaging, which is beneficial to reduce the cost and reduce the side effects of the contrast agent.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific examples.

Embodiment 1: Preparation of nuclear magnetic resonance contrast agent

2 parts of 4-arm-amino-polyethylene glycol, 2 parts of gadopentetate meglumine, 80 parts of egg yolk phospholipids, 2 parts of N-acetylneuraminic acid, 5 parts of dextran, appropriate amount of water for injection, prepared according to the following steps:

(1) Preparation of liposomal nanoparticles: Weigh egg yolk phospholipids, dextran, and 4-arm-amino-polyethylene glycol according to the formula, dissolve them in chloroform solution, stir them evenly, place them in a rotary evaporator, and Spin to form a film at 55°C, dry in vacuum, add gadopentetate meglumine solution to prepare a liposome emulsion, and obtain PEG amino-modified NMR contrast agent liposome nanoparticles by ultracentrifugation;

(2) Weigh the PEG amino-modified nuclear magnetic resonance contrast agent liposome nanoparticles and N-acetylneuraminic acid prepared in step (1), and incubate them together in water for injection for 10 minutes at 25° C. The contrast agent used in MRI of the renal pelvis is analyzed by a Malvern particle size analyzer, and the average particle size of the contrast agent is 126nm.

Embodiment 2: Preparation of nuclear magnetic resonance contrast agent

Same as Example 1, the difference is that lecithin is used instead of egg yolk phospholipid, and the average particle size of the contrast agent is 132nm as analyzed by a Malvern particle size analyzer.

Embodiment 3: Preparation of nuclear magnetic resonance contrast agent

Same as Example 1, the difference is that the amount of N-acetylneuraminic acid is 3 parts, and the average particle size of the contrast agent is 124nm as analyzed by a Malvern particle size analyzer.

Comparative example 1:

Same as Example 1, the difference is that the same weight of cholesterol was used instead of dextran, and the average particle size of the contrast agent was analyzed by a Malvern particle size analyzer to be 156nm.

Comparative example 2:

Same as Example 1, the difference is that the same weight of salicylic acid was used instead of N-acetylneuraminic acid, and the average particle size of the contrast agent was analyzed by a Malvern particle size analyzer to be 183nm.

Effect experiment example 1: The enrichment effect of contrast medium in kidney tissue

1.1 Experimental substances:

The ultrasound contrast agent and gadopentetate meglumine injection described in Examples 1-3 and Comparative Examples 1-2.

1.2 Experimental method:

90 SD rats, male, weighing 180-220g, were injected with Escherichia coli ATCC25922 at a concentration of 10 ⁸ /ml to prepare Acute pyelonephritis model. After 3 days, the urine was collected, cultured for bacteria, and the growth of the bacteria was observed. The positive results were regarded as the successful preparation of the model, and the unqualified ones were eliminated. Select 35 rats from the successfully prepared rats, and after 2 days of adaptive feeding, they are randomly divided into: model group, control group, Example 1-3 group and Comparative Example 1-2 group, with 5 rats in each group. Rats in each group were injected with the corresponding MRI contrast agent through the tail vein, and the injection dose was 0.04mmol/kg body weight in terms of gadopentetate meglumine. The control group was injected with the same amount of gadopentetate meglumine injection, and the model group was injected with the same volume saline. After 4 hours of administration, the rats were killed by neck dislocation, and the kidney tissue was taken out, rinsed with normal saline, blotted dry with filter paper, added 3 mL of concentrated nitric acid, and nitrified in a water bath at 60°C for 12 hours. The gadolinium concentration contained in rat kidney tissue is based on the content of gadopentetate meglumine in the kidney tissue of rats in the control group, and the increase or decrease of the content of gadopentetate meglumine in the kidney tissue of rats in each group is calculated relative to the control group Proportion.

1.3 Experimental results

The specific experimental results are shown in Table 1.

Table 1: Enrichment of MRI contrast agents in kidney tissue

group Gadolinium concentration (based on the control group) model group 0 control group 100% Example 1 628±25% Example 2 552±28% Example 3 568±21% Comparative example 1 180±26% Comparative example 2 254±32%

Experimental results show that Examples 1-3 of the present invention can significantly increase the targeting of gadopentetate dimeglumine liposome nanoparticles to kidney tissue sites. Wherein, the increase rate of embodiment 1 is higher than embodiment 2 and 3.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. A contrast agent for pyelonephritis MRI, characterized in that, the contrast agent consists of 2-4 parts of 4 arms-amino-polyethylene glycol, 2-4 parts of gadopentetate meglumine, phospholipid 80- It is prepared from 120 parts, 2-4 parts of N-acetylneuraminic acid, 5-10 parts of dextran and water for injection. 2. The contrast agent according to claim 1, said nuclear magnetic resonance contrast agent consists of 2-3 parts of 4-arm-amino-polyethylene glycol, 2-3 parts of gadopentetate meglumine, 80-100 parts of phospholipids, N - Prepared by 2-3 parts of acetylneuraminic acid, 5-7 parts of dextran and water for injection. 3. The contrast agent according to claim 1, said phospholipid is egg yolk phospholipid and/or lecithin. 4. The contrast agent according to claim 1, said phospholipid is egg yolk phospholipid. 5. The contrast agent according to any one of claims 1-4, which is a liposome preparation. 6. The contrast agent according to claim 5, the average particle diameter of the liposome formulation is 100-150 nm. 7. The contrast agent according to claim 5, the average particle diameter of the liposome formulation is 120-130 nm. 8. The contrast agent according to claim 1, said nuclear magnetic resonance contrast agent is prepared by the following steps: (1) Preparation of liposomal nanoparticles: Weigh phospholipids, dextran, and 4-arm-amino-polyethylene glycol according to the formula, dissolve them in chloroform solution, stir them evenly, place them in a rotary evaporator, and rotate them in a water bath Form a film, add gadopentetate dimeglumine solution after vacuum drying to prepare a liposome emulsion, and obtain PEG amino-modified nuclear magnetic resonance contrast agent liposome nanoparticles by ultracentrifugation; (2) Weigh the PEG amino-modified nuclear magnetic resonance contrast agent liposome nanoparticles prepared in step (1) and N-acetylneuraminic acid, and incubate together in water for injection at 20-30°C for 5-15min , to obtain the MRI contrast agent. 9. The use of the nuclear magnetic resonance contrast agent according to any one of claims 1-8 in the preparation of a contrast agent for diagnosing renal tissue diseases. 10. The application according to claim 9, wherein the renal tissue disease is pyelonephritis.