CN111281986A - A kind of18Application of F-fluorine labeled sulfone compound and preparation method of blood pool tracer - Google Patents

Abstract

The invention discloses an application of an ¹⁸ F-fluorine-labeled compound and a preparation method of a blood pool tracer, belonging to the technical field of radiopharmaceuticals and nuclear medicine, and solving the problems of poor imaging ability and stability of the blood pool tracer in the prior art. Not good, the imaging process is affected by glucose metabolism. The application of the ¹⁸ F-fluorine-labeled compound represented by formula I or its salt in the preparation of blood pool tracer according to the present invention,

The preparation method of the ¹⁸ F fluorine-labeled blood pool tracer of the present invention includes adding the buffer solution of the compound of formula I to the RBC buffer solution, incubating, centrifuging, collecting the red blood cell pellet, adding the buffer solution and mixing, and the obtained result is obtained. The blood pool tracer of the invention has obvious stability, good cardiac blood pool imaging ability, prolongs the residence time in the cardiac blood pool, cannot penetrate the blood-brain barrier, and has little influence on the brain tissue.

Description

Application of 18F-fluorine-labeled sulfone compound and preparation method of blood pool tracer

technical field

The invention belongs to the technical field of radiopharmaceuticals and nuclear medicine, and particularly relates to an application of an ¹⁸ F-fluorine-labeled sulfone compound in the preparation of a blood pool tracer and a preparation method of the blood pool tracer.

Background technique

The blood pool tracer is a radionuclide-labeled macromolecular substance. After intravenous injection, it is completely mixed in the blood to achieve equilibrium. Scanning or photographing with related instruments can obtain the shape of the heart's great blood vessels and the relationship between the surrounding tissues and organs. It can also obtain cardiac function information through quantitative analysis, which can be used for the diagnosis of coronary heart disease, cardiomyopathy, congenital heart disease, valvular heart disease and other diseases, to monitor the toxicity of drugs to the heart, and to diagnose chronic intermittent bleeding. In particular, lower gastrointestinal bleeding is of great significance.

With the continuous development of cardiovascular nuclear medicine, new blood pool tracers are emerging, but each has its own shortcomings and deficiencies. For example, with ¹³¹ I-labeled human serum albumin (HSA), the thyroid gland needs to be blocked three days before imaging. The patient's radiation dose is high and the nuclide energy is high, which is not conducive to the application of gamma cameras. The application of ^99m Tc-labeled HSA and red blood cells (RBC) avoids the above problems, and the imaging quality is improved. At present, the blood pool tracers used clinically mainly use ^99m Tc-labeled autologous red blood cells. RBC is the highest content of visible components in blood, which is easy to separate, operate and culture in vitro, and has good imaging quality. However, the labeling rate of ^99m Tc-RBC is often unstable, which is greatly affected by the type and dosage of the applied drug. The radioactivity in blood tended to decrease within 15 minutes of infusion of ^99m Tc-HSA, while the radioactivity in liver increased. After 90 minutes, the radioactivity in the blood decreased significantly, and the radioactivity in the liver and lung was higher, which affected the imaging of the blood pool of the heart. In addition, this type of imaging agent needs to be detected by SPECT, which has lower image acceptance efficiency and poorer image quality than that obtained by PET/CT imaging. There are also reports on the use of radionuclides (such as fluorine-18, copper-64, gallium-68, etc.) and Evans blue complex (NOTA-EB) to label HSA as a blood pool tracer, because it needs to be combined with HSA. After imaging, the effect is not ideal and the stability is poor. At present, there are related studies on the labeling of RBCs with ¹⁸ F-FDG, but since FDG is affected by glucose metabolism, the labeling process requires fasting and glucose consumption.

Therefore, to provide a blood pool tracer with good cardiac blood pool imaging capability and good stability has become an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is: to provide the application of the ¹⁸ F-fluorine-labeled sulfone compound represented by formula I or its salt in the preparation of blood pool tracers, so as to solve the problem of poor imaging ability of blood pool tracers in the prior art , the problem of poor stability.

The present invention also provides a method for preparing a blood pool tracer by using the compound of formula I as a raw material.

The technical scheme adopted in the present invention is as follows:

The application of the ¹⁸ F-fluorine-labeled compound represented by formula I or its salt in the preparation of blood pool tracer according to the present invention,

Among them, n=0-5.

In the preparation method of a ¹⁸ F fluorine-labeled blood pool tracer according to the present invention, the buffer solution of the compound of formula I is added to the RBC buffer, incubated, centrifuged, the red blood cell precipitate is collected, and the buffer solution is added and mixed to obtain ¹⁸ F Fluorine-labeled blood pool tracer.

In the technical scheme of the present invention, the buffer of the compound of formula I is a 1-fold PBS solution containing the compound of formula I, with a pH value of 6-8, preferably a pH value of 7.4;

Or/and the RBC buffer is a 1-fold PBS buffer solution containing RBC, with a pH value of 6-8, preferably a pH value of 7.4.

In the technical solution of the present invention, when the compound of formula I in the buffer of the compound of formula I is 1-20 mCi, the red blood cell count in the RBC buffer is 0.8^9-2^9.

In the technical solution of the present invention, the incubation conditions are incubation at 35-38°C for 30-60 minutes; preferably, incubation at 37°C for 45 minutes.

In the technical solution of the present invention, the centrifugation is centrifugation under low temperature conditions.

The temperature of the centrifugation is below 20°C.

In the technical scheme of the present invention, during the centrifugation, the centrifugal force is 300-400×g.

In the technical scheme of the present invention, the collected red blood cell pellets are added to the PBS buffer and centrifuged repeatedly for 2-4 times.

In the technical solution of the present invention, the concentration of red blood cells in the ¹⁸ F fluorine-labeled blood pool tracer is 3^12/L to 6^12/L.

It should be noted that when the blood pool tracer of the present invention is used in humans, the red blood cells used in the preparation process are human autologous red blood cells; when the blood pool tracer of the present invention is used in animals, the red blood cells used in the preparation process are the red blood cells of the animal. red blood cells.

The preparation method of the RBC buffer in the present invention is as follows: mixing blood with 5-10 times the volume of PBS containing 2-8 mM EDTA to obtain the diluted blood solution in a 50 mL centrifuge tube, and dropping the diluted blood solution in 15 mL centrifuge at 300-400 x g for 30 min at 20°C; remove all the supernatant liquid so that the RBS layer is not disturbed; add 20-30 mL of PBS solution (containing 5mM EDTA) to fill the centrifuge tube , and pipette gently to mix the RBS; centrifuge again at 300-400 x g for 20-60 min at 20°C; remove all buffers, and add an appropriate amount of PBS buffer to the cell pellet to obtain RBC buffer.

Compared with the prior art, the present invention has the following beneficial effects:

The invention has scientific design and simple method. The invention creatively uses fluorine-18-labeled sulfone compounds to prepare blood pool tracers, and uses macrocyclic polyamine chelating groups (such as NOTA) to complex metal radionuclides (gallium-68, copper-64, Compared with the method for labeling with technetium-99), the blood pool tracer of the present invention has obvious stability and advantages by forming a stable carbon-fluorine-18 chemical bond-labeled blood pool tracer.

Observation of blood pools after injection of the imaging agent into mammals shows that the imaging agent has good imaging ability of cardiac blood pools.

The labeling method of the invention is simple, the precursor is easy to obtain, and the observation of the mammalian heart blood pool can be simply and effectively realized without being affected by blood sugar (without fasting), and the imaging effect is good; and the existing cardiac blood pool tracer In contrast, the tracer prolongs the residence time in the blood pool of the heart, and is mainly excreted through the kidneys and bladder, with a faster excretion rate and reduced nephrotoxicity; it cannot penetrate the blood-brain barrier and has little effect on brain tissue.

Description of drawings

Accompanying drawing 1 is the HPLC chart of the compound of formula I of the present invention using radioactive detector;

Accompanying drawing 2 is the HPLC figure of the compound of formula I of the present invention using ultraviolet detector;

Figure 3 is a micro-PET/CT scan image of normal mice 1 hour after injection of 18F-VS1-RBC;

Figure 4 is a micro-PET/CT scan image of normal mice 5 hours after injection of 18F-VS1-RBC.

Fig. 5 is a graph showing the organ biodistribution (X±S) (%ID/g) of 18F-VS1-RBC in normal mice.

Detailed ways

The present invention will be described in further detail below in conjunction with the embodiments. The embodiments of the present invention are only used to illustrate the technical solutions of the present invention, but not to limit the present invention. All belong to the protection scope of the present invention.

Example 1

The present embodiment discloses the preparation method of the compound of formula I ¹⁸ F-VS1 of the present invention, specifically:

The ¹⁸ F-fluoride ion prepared by the accelerator bombardment was trapped with an activated QMA column, and then the ¹⁸ F-fluoride ion captured by the QMA column was washed with a 2.5% TBAB acetonitrile/water mixed solution to the reaction tube of the fluorine multifunctional synthesis module After three times of drying with anhydrous acetonitrile, a portion of ¹⁸ F-TBAF solution (about 50 mCi) was added to 2 mg of the compound of formula II (n=1) in anhydrous acetonitrile (60 μL) solution, sealed and heated at 95 ° C for 15 min. , and a part of the reaction solution was taken out and separated by radio-HPLC. The chromatographic conditions are as follows: ODS C18 column is used as the chromatographic column, 0.1% trifluoroacetic acid in acetonitrile solution is used as mobile phase A, water containing 0.1% trifluoroacetic acid is used as mobile phase B, the flow rate is 1 mL/min, and washing is carried out as specified in the table below. disengage.

time (min) Mobile phase A (%) Mobile phase B (%) 0 5 95 2 5 95 twenty two 95 5 28 95 5

The HPLC chromatograms are shown in Figures 1 and 2.

The collected eluate containing the compound of formula I is evaporated to remove acetonitrile to obtain the compound of formula I, which is denoted as ¹⁸ F-VS1. A part of the compound ¹⁸ F-VS1 of the formula I and the standard solution ¹⁹ F-VS1 were mixed and analyzed by HPLC, and the peak times were consistent.

Example 2

This embodiment discloses the preparation of blood pool tracer using the compound of formula I prepared in Example 1, specifically:

RBC preparation: Under isoflurane anesthesia, 200 μL of blood was collected after euthanizing mice by cervical dislocation, and the blood was mixed with 10 times the volume of PBS containing 5 mM EDTA. In a 50 mL centrifuge tube, the diluted blood solution was dropped on 15 mL of leukocyte separation solution (ρ=1.077 g/mL), and centrifuged at 1000 r/min for 30 min at 20°C. Remove all supernatant liquid, leaving the RBS layer undisturbed. Add 30 mL of PBS solution (containing 5 mM EDTA) to fill the centrifuge tube, and pipette gently to mix the RBCs. Centrifuge again at 300×g 1000 r/min for 30 min at 20°C. All buffers were removed, and 10-100 μL of an appropriate amount of PBS buffer was added to the cell pellet as RBC buffer for use.

The eluate containing the compound of formula I collected in Example 1 was evaporated to remove acetonitrile, and the pH value was adjusted to about 7 to prepare an ¹⁸ F-VS1 solution containing 1 times PBS for use.

The PBS solution of 3-4 mCi ¹⁸ F-VS1 was added to the above RBC buffer, and incubated at 37° C. for 45 min. Centrifuge at 300×g at 1000 r/min for 5 min at 20°C. The erythrocyte pellet was collected and mixed with an appropriate amount of 2 mL of PBS buffer. Repeat addition of PBS buffer/centrifugation/collection of erythrocytes twice. Finally, 150 μL of 1x PBS buffer was added and mixed to obtain ¹⁸ F-VS1-labeled blood pool tracer for micro PET/CT imaging.

Example 3

This example discloses the imaging experiment of RBCs labeled with the blood pool tracer ¹⁸ F-VS1 prepared in Example 2:

The normal mice were placed on a PET/CT scanning bed, and maintained anesthesia with a volume fraction of 1% isoflurane-oxygen gas mixture to detect respiration, and injected 50-200 μCi of ¹⁸ F-VS-labeled red blood cells into the tail vein of the mice. tracer solution. Mice were statically imaged at different time points after injection, and after acquisition and image reconstruction, the myocardium, blood pool, liver, and kidney were delineated on whole-body attenuation-corrected coronal images using the software provided by the vendor, Inveon Research Workplace (SIEMENS) software. , brain, muscle, bone, stomach, small intestine, and brain were used as regions of interest (ROI), and the ¹⁸ F-VS1 labeled erythrocyte tracer solution was obtained by Inveon Research Workplace data processing. The percentage of injected dose per gram of tissue at this time point (%ID /g).

The results are shown in Figures 3 and 4. From the micro-PET/CT imaging images and in vivo distribution of normal mice after injection of ¹⁸ F-VS1-labeled erythrocyte tracking solution, after injection of ¹⁸ F-VS1-labeled erythrocyte tracking solution Imaging of mice 1 hour after the solution showed that the distribution of radioactivity in the heart and blood pool was obvious, the distribution of high radioactivity in the bladder, and the distribution of mild radioactivity in the liver, kidney, lung, bone and brain, etc. can be seen; 5h after injection, the radioactivity in the blood pool of the heart was The distribution is still clear, the distribution of radioactivity in the stomach and intestines is increased, the distribution of radioactivity in the bladder is reduced, and the distribution of radioactivity in the liver and other soft tissues is reduced. This indicates that the ¹⁸ F-VS1-labeled erythrocyte tracer solution has a long residence time in the heart blood pool, and is mainly excreted by the kidney and bladder. brain barrier. The organ biodistribution (X±S) (%ID/g) of ¹⁸ F-VS1 in normal mice is shown in FIG. 5 .

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the protection scope of the present invention. If the technical problem is still consistent with the present invention, it should be included within the protection scope of the present invention.

Claims (10)

1. As shown in formula I¹⁸The application of the F-fluorine marked sulfone compound or the salt thereof in the preparation of the blood pool tracer agent,

wherein n is 0 to 5.

2. A kind of¹⁸The preparation method of the F fluorine labeled blood pool tracer agent is characterized by adding a buffer solution of the compound shown in the formula I into an RBC buffer solution, incubating, centrifuging, collecting erythrocyte sediment, adding the buffer solution, and mixing to obtain the F fluorine labeled blood pool tracer agent¹⁸F fluorine labelled blood pool tracers.

3. The method of claim 2, wherein the buffer solution of the compound of formula I is a 1-fold PBS solution containing the compound of formula I, and has a pH of 6 to 8, preferably a pH of 7.4;

or/and the RBC buffer solution is 1-fold PBS buffer solution containing RBC, and the pH value is 6-8, preferably the pH value is 7.4.

4. The method of claim 2 or 3, wherein when the compound of formula I is 1-20 mCi in the compound of formula I buffer, the red blood cell count in RBC buffer is 0.8^ 9-2 ^ 9.

5. The method according to claim 2 or 3, wherein the incubation is carried out at 35-38 ℃ for 30-60 min; preferably, the incubation is carried out at 37 ℃ for 45 min.

6. The method of claim 2 or 3, wherein the centrifugation is centrifugation under cryogenic conditions.

7. The method of claim 6, wherein the temperature of the centrifugation is less than 20 ℃.

8. The method according to claim 2 or 3, wherein the centrifugal force is 300 to 400 Xg.

9. The method according to claim 8, wherein the collected erythrocyte pellet is added to PBS buffer solution and centrifuged repeatedly for 2 to 4 times.

10. The method of claim 2, wherein the step of preparing the composition is carried out in a batch process¹⁸The concentration of the red blood cells in the F fluorine marked blood pool tracer is 3^12/L to 6^ 12/L.

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