Small-molecule targeted CT contrast agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of small-molecule contrast agents, in particular to a small-molecule targeted CT contrast agent and a preparation method thereof. The structural general formula is shown in the specification, wherein R is or. According to the micromolecule targeted CT contrast agent provided by the invention, a mode of combining a triiodo benzene ring contrast core and a glycosyl targeted head is adopted, and a targeted molecule with a stable structure and moderate molecular weight is formed and has strong X-ray attenuation capability. The glycosyl group in the contrast agent can specifically recognize and combine with a receptor over-expressed on the surface of pathological tissues such as tumors, so that the contrast agent can be actively enriched in a focus area, and the imaging sensitivity is improved. Meanwhile, a targeting group in the contrast agent molecule can be combined with a sugar transport receptor highly expressed on the surface of a tumor cell, so that the residence time of the contrast agent in a tumor tissue is prolonged, and an imaging window is widened.

Description

Technical Field

[0001] This invention relates to the field of small molecule targeted CT contrast agent technology, and in particular to a small molecule targeted CT contrast agent, its preparation method, and its application. Background Technology

[0002] Currently, widely used non-ionic small-molecule iodine contrast agents in clinical practice mainly include iohexol, iopromide, and iopamidol, all of which have a core structure based on a triiodophenyl ring skeleton. These compounds have low solution viscosity, moderate osmotic pressure (close to physiological levels), good water solubility, and rapid renal clearance, thus possessing high short-term safety. However, their pharmacokinetic characteristics also have significant limitations: their blood circulation half-life is extremely short (usually less than 30 minutes), and they are rapidly excreted from the body mainly through glomerular filtration, resulting in a narrow vascular phase contrast enhancement window. Therefore, high-dose bolus injections using high-pressure injectors are often required clinically to ensure sufficient contrast enhancement, but this inevitably increases the patient's total iodine load, thereby increasing the risk of contrast-induced nephropathy (CIN), especially in patients with renal insufficiency or diabetes. Simultaneously, some patients may experience allergic-like reactions or even severe hypersensitivity reactions, further limiting their long-term or repeated use.

[0003] In recent years, researchers have attempted to couple triiodobenzene backbones with polysaccharides, polymers, or peptides to prolong blood pool retention time and endow them with active targeting capabilities. However, most systems suffer from excessively high viscosity due to their large molecular weight, or have lengthy synthetic routes and significant batch-to-batch variations, hindering clinical translation. Although divalent glycosyl groups can be inserted into the binary triiodobenzene ring backbone to maintain a molecular weight <2000 Da and improve the water solubility and viscosity of contrast agents, their stability is poor.

[0004] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a small molecule targeted CT contrast agent with better dilution stability and higher contrast brightness.

[0006] To achieve this objective, the present invention adopts the following technical solution: Firstly, a small-molecule targeted CT contrast agent has the following general structural formula: , where R is or .

[0007] Secondly, a method for preparing the small molecule targeted CT contrast agent described in the first aspect, comprising: compound After dissolution, it reacts with HATU, DIPEA, and other compounds. Mixing yields a compound ; The compound Dissolve, and add a mixed solution of dichloromethane and trifluoroacetic acid under ice bath conditions, reacting to obtain the compound. ; After dissolving compound YJY-77-1, it was combined with HATU, DIPEA, and other compounds. The mixture was reacted at room temperature to obtain the small molecule targeted CT contrast agent. , among which, YJY-77-1 is (4-((3,5-bis((2,3-dihydroxypropyl)carbamoyl)-2,4,6-triiodophenyl)amino)-4-oxobutanoic acid).

[0008] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0009] As a preferred technical solution, in the preparation method of the small molecule targeted CT contrast agent, the equivalent ratio of the compound YJY-77-1 to the compound RSM3-monosaccharide is 1:1-1.3.

[0010] As a preferred technical solution, in the method for preparing the small molecule targeted CT contrast agent, the equivalent ratio of compound 1 to compound 2 is 1:1-1.5.

[0011] Thirdly, a method for preparing the small molecule targeted CT contrast agent described in the first aspect, comprising: compound After dissolution, it reacts with HATU, DIPEA, and other compounds. Mixing yields a compound ; The compound Dissolve, and add a mixed solution of dichloromethane and trifluoroacetic acid under ice bath conditions, reacting to obtain the compound. ; After dissolving compound YJY-77-1, it was combined with HATU, DIPEA, and other compounds. The mixture was reacted at room temperature to obtain the small molecule targeted CT contrast agent. .

[0012] As a preferred technical solution, in the preparation method of the small molecule targeted CT contrast agent, the equivalent ratio of the compound YJY-77-1 to the compound RSM3-disaccharide is 1:1-1.3.

[0013] As a preferred technical solution, in the method for preparing the small molecule targeted CT contrast agent, the equivalent ratio of compound 1 to compound 2 is 1:1-1.5.

[0014] Fourthly, the application of a small molecule targeted CT contrast agent as described in the first aspect in targeted contrast imaging.

[0015] Beneficial effects: Compared with existing technologies, the small molecule targeted CT contrast agent provided by this invention ensures that each molecule contains three iodine atoms and a small molecule glycosyl targeting group, giving it good water solubility, dilution stability, and viscosity. Preliminary animal CT experiments show that, at equimolar concentrations, the small molecule targeted contrast agent exhibits superior imaging brightness and imaging window compared to iohexol at different time points. Attached Figure Description

[0016] Figure 1 shows the CT test results of a small molecule targeted CT contrast agent with a concentration of 27.60 mmol / mL provided in the embodiment of the present invention; Figure 2 The results are CT test results for a small molecule targeted CT contrast agent concentration of 13.80 mmol / mL provided in this embodiment of the invention. Figure 3 This is a comparative HPLC chromatogram of the stability test (4 Day) of the contrast agent YJY-80-1 in water provided by the present invention; Figure 4 This is a comparative HPLC chromatogram of the stability test (4 Day) of the contrast agent YJY-79-1 in water provided by this invention; Figure 5 This is a comparative HPLC chromatogram of the stability test (40 hours) of the small molecule targeted CT contrast agent with serial number YJY-86-2 in water. Figure 6 This describes the distribution of contrast agents YJY-79-1 and YJY-80-1 provided by this invention in animals compared to the existing contrast agent iohexol. Figure 7 This describes the metabolism of contrast agents YJY-79-1 and YJY-80-1 provided by this invention with the existing contrast agent iohexol. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "package" are used in this specification… When "includes", it indicates the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0020] Additionally, the structural formula of the compound designated YJY-86-2 is as follows:

[0021] The HPLC testing process involved in this invention includes: The chromatographic conditions involved in HPLC are shown below: Liquid chromatography system: Agilent LC system; Column: ZORBAX RR Eclipse Plus C18, 95A, 4.6 x 150 mm, 3.5 μm; Column temperature: 25℃; Autosampler temperature: 25℃; Injection volume: 5 μL; Mobile phase: (Aqueous phase: 0.1% formic acid aqueous solution, Organic phase: 0.1% formic acid in acetonitrile); Flow rate: 0.5 mL / min; Run time: 15 min; Gradients are shown in the table below:

[0022] Automatic syringe needle washing solution (F11): methanol.

[0023] The CT parameter conditions involved in this invention are as follows: Tube voltage: 80kV; Tube current: 5mA; Beam filter: 1.5mm aluminum + 0.1mm copper; Scan angle: 360 degrees; Number of scan projections: 450; Distance from light source to detector (SDD) = 1320mm; Distance from light source to object (SOD) = 770mm; Detector model: Varex PaxScan4343CB; X-ray tube model: Varex G-242; Image reconstruction pixel size: 0.2mm; Sample preparation: The target object was dissolved in water and placed in a 1.5 mL centrifuge tube for CT scanning.

[0024] The following specific preparation examples will further explain and illustrate the small molecule targeted CT contrast agent and its preparation method provided by the present invention.

[0025] Preparation of intermediate YJY-77-1 in Example 1: The corresponding synthesis route is shown below: Specifically, the steps include the following: first step

[0026] Procedure: Compound 2 (1.5 g, 1.2 eq) was dissolved in DMF (40 mL), HATU (4.0 g, 1.5 eq) and DIPEA (3.7 mL, 3 eq) were added, and finally compound 1 (5.0 g, 1.0 eq) was added and stirred at room temperature for 8 hours.

[0027] Detection: LCMS showed that most of the material was product, and the remaining 26% of raw material was stopped and then processed.

[0028] Post-processing: Pour the reaction solution into 300 mL of water, add 200 mL of ethyl acetate / methanol (10 / 1) for extraction and separation, repeat 5-6 times, wash the organic phase with saturated sodium chloride solution, dry with anhydrous sodium sulfate, and then evaporate to dryness to obtain the crude product.

[0029] Purification: Column purification (EA:PE=0:1, 1:1, 3:2, 2:1, 3:1, 1:0, EA:MeOH=20:1, 10:1) separated the product YJY-76-1 (1.8 g, 29.5% yield) as a white solid.

[0030] LCMS (ESI): m / z Calcd for C 22 H 31 I3N3O9, [M+H] +:861.9, found:862.2. Step 2

[0031] Procedure: Dissolve YJY-76-1 (1.8 g) in DCM (10 mL), add TFA / DCM (1 / 1, 10 mL) to the stirred reaction solution under ice bath, and stir at room temperature for 0.5 hours.

[0032] Detection: LCMS showed that the reaction was complete.

[0033] Post-treatment: After adding 100 mL of ethyl acetate and 20 mL of petroleum ether to the reaction solution, a white solid precipitated. After stirring for 30 minutes, the mixture was filtered to obtain product YJY-77-1 (1.4 g, crude) as a white solid.

[0034] LCMS (ESI): m / z Calcd for C 18 H 23 I3N3O9, [M+H] + :805.8, found:806.1. Example 2 Preparation of contrast agent small molecule YJY-80-1:

[0035] Synthesis method: Procedure: Dissolve YJY-77-1 (1.4 g, 1.0 eq) in DMF (20 mL), add RSM3-monosaccharide (388 mg, 1.0 eq), HATU (993 mg, 1.5 eq) and DIPEA (910 μL, 3.0 eq) to the reaction mixture, and stir the mixture at room temperature for 1-2 h.

[0036] Detection: LCMS showed that the reaction was complete.

[0037] Post-processing and purification: 100 mL of ethyl acetate and 10 mL of petroleum ether were added to the reaction system, and a large amount of white solid precipitated. After 2 hours of slurrying, the solid was filtered and then purified by Pre-HPLC and lyophilized to obtain product YJY-80-1 (750 mg, 42.7% yield) as a white solid.

[0038] 1H NMR (400 MHz, d6-DMSO) δ8.50 (t, J = 5.6 Hz, 1H), 8.37 (t, J = 5.6Hz, 1H), 7.95 – 7.84 (m, 1H), 5.46 (d, J = 12.0 Hz, 2H), 5.14 (dd, J = 18.8,4.9 Hz, 1H), 5.01 (d, J = 3.6 Hz, 1H), 4.96 (d, J = 4.6 Hz, 1H), 4.92 (d, J =5.0 Hz, 1H), 4.84–4.74 (m, 1H), 4.72–4.65 (m, 1H), 4.56 (t, J = 5.6 Hz, 1H), 4.51–4.45 (m, 1H), 4.14 (t, J = 7.1 Hz, 2H), 3.99 (dt, J = 24.2, 13.7 Hz, 2H), 3.69 (dq, J = 10.6, 5.5 Hz, 4H), 3.51–3.44 (m, 3H), 3.24 (ddd, J = 20.8,11.7, 6.2 Hz, 4H), 3.17–3.08 (m, 4H), 3.06–3.00 (m, 1H), 2.98–2.92 (m, 1H), 2.38 (t, J = 6.7 Hz, 2H). HRMS (ESI): m / z Calcd for C 26 H 38 I3N4O 14 [M+H] + :1010.9440, found:1010.9495. Example 2 Preparation of contrast agent small molecule YJY-79-1:

[0039] Synthesis method: Procedure: Dissolve YJY-77-1 (1.5 g, 1.0 eq) in DMF (20 mL), add RSM3-disaccharide (1.012 g, 1.0 eq), HATU (1.06 g, 1.5 eq) and DIPEA (972 μL, 3.0 eq) to the reaction, and stir the reaction at room temperature for 1-2 h.

[0040] Detection: LCMS showed that the reaction was complete.

[0041] Post-processing and purification: 100 mL of ethyl acetate and 10 mL of petroleum ether were added to the reaction system, and a large amount of white solid precipitated. After 2 hours of slurrying, the solid was filtered and purified by Pre-HPLC and then freeze-dried to obtain product YJY-79-1 (1.0 g, 40.3% yield) as a white solid.

[0042] 1 H NMR (400 MHz, d6-DMSO) δ8.55 (dd, J = 16.8, 10.9 Hz, 1H), 8.34 (d,J = 22.6 Hz, 1H), 8.07 (d, J = 7.8 Hz, 1H), 8.00–7.66 (m, 3H), 5.47 (d, J =11.2 Hz, 2H), 5.13 (t, J = 10.5 Hz, 1H), 5.04–4.86 (m, 8H), 4.83–4.74 (m,1H), 4.67 (d, J = 13.3 Hz, 1H), 4.60–4.45 (m, 5H), 4.13 (dd, J = 7.6, 2.5 Hz, 3H), 4.05–3.88 (m, 2H), 3.67 (d, J = 7.7 Hz, 5H), 3.49–3.44 (m, 4H), 3.27–3.20 (m, 5H), 3.15–3.03 (m, 8H), 2.95 (dd, J = 10.7, 6.1 Hz, 2H), 2.45–2.31(m, 4H). HRMS (ESI): m / z Calcd for C 38 H 57 I3N6O 22 Na, [M+Na] + :1353.0552, found:1353.0516. Experimental Example 1 The small molecule targeted CT contrast agents (YJY-79-1) and (YJY-80-1) prepared in this invention were formulated into a solution with a concentration of 27.60 mmol / mL and subjected to CT testing. Figure 1 As shown in the table below, the results are compared with those of iohexol:

[0043] Experiment Example 2 The CT results, obtained after diluting all the samples by half with water, showed a sample concentration of 13.80 mmol / mL. Figure 2 As shown:

[0044] As can be seen from the above, at the same concentration, YJY-80-1, YJY-79-1 and iohexol have similar CT brightness and mean values. However, YJY-80-1 and YJY-79-1 have added sugar structure, which gives them a sugar-targeting effect compared to iohexol.

[0045] Experimental Example 3 Stability comparison of contrast agents YJY-80-1, YJY-79-1, and YJY-86-2: The stability test (4 Days) of contrast agent YJY-80-1 in water is compared using HPLC.

[0046] Combination Figure 3 As shown in the figure, the HPLC data indicate that YJY-80-1 exhibits good stability over 4 days.

[0047] Experiment Example 4 Stability test of contrast agent YJY-79-1 in water (4 Day) HPLC comparison table:

[0048] Combination Figure 4 As shown in the figure, the HPLC data indicate that YJY-79-1 exhibits good stability over 4 days.

[0049] Experimental Example 5 Stability test of contrast agent YJY-86-2 in water (40 hours) HPLC comparison table:

[0050] Combination Figure 5 As shown in the HPLC data, new impurities were detected in YJY-86-2 after 40 hours, the purity decreased by 17.6%, and the stability was poor.

[0051] In conclusion, based on the above comparison, it can be seen that YJY-80-1 and YJY-79-1 have better stability than YJY-86-2.

[0052] Experimental Example 5 After establishing a subcutaneous 4T1 xenograft model in female Balb / c mice, when the tumor volume grew to approximately 200 mm³ or greater, 50 μL of 0.2 mol / L iohexol, YJY-79-1, or YJY-80-1 was injected into the tumor, respectively. The mice were scanned using an energy-dispersive CT imaging system at 5 min, 30 min, 1 h, and 4 h after administration. Results are referenced. Figures 6 to 7 As shown, all images were acquired under the same parameters, and the CT value was measured by selecting the region of interest (ROI) in the tumor area. Each mouse underwent three repeated measurements, and the average value was used as the final data. The results showed that, at the same dosage, YJY-79-1 and YJY-80-1 exhibited significantly higher imaging signal intensity and longer imaging duration at the tumor site than iohexol, suggesting that both have superior imaging performance in tumor imaging.

[0053] In summary, this invention provides a small-molecule targeted CT contrast agent and its preparation method. Its general structural formula is shown below: , where R is or .

[0054] The small-molecule targeted CT contrast agent provided by this invention has a core advantage stemming from the ingenious combination of a "triiodobenzene ring contrast core" and a "glycosyl targeting head," forming a structurally stable and appropriately sized targeting molecule. This structural design is not a simple functional stacking, but rather the result of synergistic optimization. First, its core utilizes a clinically validated triiodobenzene ring framework, ensuring that the molecule itself possesses the fundamental prerequisite for a CT contrast agent—strong X-ray attenuation capability—thus inheriting the advantages of high contrast brightness and good stability of traditional non-targeted contrast agents (such as iohexol). Crucially, the researchers did not employ a complex polymer coupling strategy, but instead precisely connected appropriately sized glycosyl modules (such as monosaccharides or disaccharides) via covalent bonds. This design cleverly avoids the problems that traditional large-molecule targeted contrast agents may have, such as complex synthesis, high solution viscosity, and unclear in vivo metabolic pathways, while successfully endowing the molecule with active targeting capabilities. This unique "small molecule + targeted" architecture brings multiple clinical benefits. Because the glycosyl groups can specifically recognize and bind to receptors overexpressed on the surface of lesions such as tumors, this contrast agent can actively accumulate in the lesion area, achieving precise imaging. More importantly, its active retention at the lesion site results in a better imaging signal-to-noise ratio and a longer diagnostic time window. This not only improves image contrast but also lays a solid material foundation for the detection of early-stage small tumors, precise delineation of tumor boundaries, and timely assessment of treatment efficacy. This characteristic promises to achieve better image quality while reducing drug dosage and iodine exposure risks, providing a strong candidate compound basis for achieving highly sensitive detection of early-stage tumors.

[0055] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A small molecule targeted CT contrast agent, the general structural formula of which is shown below: , where R is or .

2. A method for preparing the small molecule targeted CT contrast agent according to claim 1, characterized in that, include: compound After dissolution, it reacts with HATU, DIPEA, and other compounds. Mixing yields a compound ; The compound Dissolve, and add a mixed solution of dichloromethane and trifluoroacetic acid under ice bath conditions, reacting to obtain the compound. ; After dissolving compound YJY-77-1, it was combined with HATU, DIPEA, and other compounds. The mixture was reacted at room temperature to obtain the small molecule targeted CT contrast agent. .

3. The method for preparing the small molecule targeted CT contrast agent according to claim 2, characterized in that, The equivalent ratio of compound YJY-77-1 to compound RSM3-monosaccharide is 1:1-1.

3.

4. The method for preparing the small molecule targeted CT contrast agent according to claim 2, characterized in that, The equivalent ratio of compound 1 to compound 2 is 1:1-1.

5.

5. A method for preparing the small molecule targeted CT contrast agent according to claim 1, characterized in that, include: compound After dissolution, it reacts with HATU, DIPEA, and other compounds. Mixing yields a compound ; The compound Dissolve, and add a mixed solution of dichloromethane and trifluoroacetic acid under ice bath conditions, reacting to obtain the compound. ; After dissolving compound YJY-77-1, it was combined with HATU, DIPEA, and other compounds. The mixture was reacted at room temperature to obtain the small molecule targeted CT contrast agent. .

6. The method for preparing the small molecule targeted CT contrast agent according to claim 5, characterized in that, The equivalent ratio of compound YJY-77-1 to compound RSM3-disaccharide is 1:1-1.

3.

7. The method for preparing the small molecule targeted CT contrast agent according to claim 5, characterized in that, The equivalent ratio of compound 1 to compound 2 is 1:1-1.

5.

8. The application of the small molecule targeted CT contrast agent according to claim 1 in targeted contrast imaging.

Images