Diagnosis and treatment integrated BODIPY boron medicine with high boron-10 loading capacity and preparation method of diagnosis and treatment integrated BODIPY boron medicine
By developing BODIPY boron drugs with high boron-10 loading and combining them with fluorescence and photoacoustic imaging, the problems of insufficient boron loading and inaccurate monitoring in boron drugs during BNCT have been solved, achieving precision and high efficiency in BNCT treatment.
Patent Information
- Application Number
- CN202511713998.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-01-27
AI Technical Summary
Current boron neutron capture therapy (BNCT) uses boron drugs with limited boron loading and insufficient targeting, making it difficult to achieve efficient enrichment and stable concentration in tumor tissues. Existing imaging technologies are not precise enough for monitoring, and there are issues of radiation exposure and high costs.
To develop a high boron-10 loading, therapeutically integrated BODIPY boron drug, combining fluorescence and photoacoustic dual-modal imaging capabilities, and introducing a strong electron-withdrawing group -CF3 through the formation of a boron ester ring by the BODIPY core structure and ortho-dihydroxy group, thereby achieving efficient boron carrier and real-time dynamic monitoring.
It achieves high boron loading and structural stability, and has real-time, non-invasive, high-resolution boron drug distribution monitoring, improving the accuracy and efficacy of BNCT treatment.
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Figure CN121401414A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of biomedicine and nuclear medicine, specifically to a boron-rich diagnostic and therapeutic boron drug for boron neutron capture therapy (BNCT) and its preparation method. Background Technology
[0002] Boron neutron capture therapy (BNCT) is a promising binary targeted radiotherapy technique. Its therapeutic principle is based on the following nuclear reaction process: first, boron-10 (… 10 B) Isotope-based drugs are delivered to tumor tissue and efficiently enriched there. The tumor site is then irradiated using thermal or ultrathermal neutron beams. When thermal neutrons are captured by the boron-10 isotope enriched within tumor cells, a transient nuclear fission reaction occurs, releasing highly linearly energy-transferring alpha particles and recoil lithium-7 nuclei. These particles have an extremely short range (approximately 10 μm), equivalent to the diameter of a single cell, thus precisely destroying the structure of cancer cells, inducing irreversible apoptosis, while maximally protecting surrounding normal tissue. This therapy, due to its unique advantages of high precision, low toxicity, and short treatment duration, shows great potential in the treatment of recurrent, invasive, and refractory solid tumors.
[0003] Although the concept of boron-neutron transplantation (BNCT) was proposed as early as the 1930s, its clinical translation has long been limited by two core factors: the development of stable and efficient neutron sources and high-performance boron drugs. Regarding boron drugs, the number of drugs approved for clinical use globally is currently very limited, mainly second-generation boron drugs such as 4-boronic acid-L-phenylalanine (L-BPA) and boron mercaptododecanoate (BSH). Among them, L-BPA is the most widely used drug, mainly accumulating in metabolically active tumor cells via the L-amino acid transporter (LAT-1). However, existing boron drugs generally suffer from key problems such as insufficient targeting, short tumor retention time, limited boron loading, and relatively low concentrations in tumor and normal tissues. For example, BPA has a low boron content, requiring high-dose, long-term infusion (usually exceeding 2 hours), and its targeting effect on some cancers (such as liver cancer and pancreatic cancer) is not ideal, limiting its clinical application. Furthermore, although BSH has a high boron content, its targeting is poor, making it difficult to effectively accumulate within cells. These factors make it difficult for the local boron-10 concentration in the tumor to consistently reach the threshold required for clinical treatment (usually above 20 μg / g, with a tumor / normal tissue boron concentration ratio T / N ≥ 3), severely limiting the final efficacy of BNCT.
[0004] The successful implementation of BNCT heavily relies on precise understanding of the dynamic distribution of boron drugs in vivo, particularly within tumor tissue. Before treatment, the timing and dosage of neutron irradiation must be precisely planned based on the pharmacokinetic parameters of the boron drug. Currently, positron emission tomography (PET) technology is commonly used in clinical practice for monitoring, for example, using... 18 F-labeled BPA analogs ([ 18 F]FBPA) was used as a PET probe to simulate the distribution of BPA (Jing H. Chem. Commun., 2021, 57, 8953-8956). However, [ 18 F]FBPA differs from BPA in molecular structure (F atoms replace H atoms on the benzene ring), and its pharmacokinetic behavior cannot fully represent therapeutic doses of BPA. This uncertainty poses a potential risk to the development of BNCT treatment regimens. Furthermore, PET technology itself suffers from problems such as radiation exposure, high cost, and limited temporal resolution. While magnetic resonance imaging (MRI) is radiation-free, it lacks specificity for boron and has relatively insufficient sensitivity, making it difficult to achieve real-time dynamic monitoring of boron drug metabolism.
[0005] In recent years, the rapid development of optical imaging technology has provided new solutions for non-invasive, real-time monitoring of boron drug behavior in vivo. Fluorescence imaging, based on signal changes in fluorescent reporter groups, boasts advantages such as high sensitivity, high spatiotemporal resolution, and ease of operation, enabling real-time monitoring of molecular dynamics within organisms. Photoacoustic imaging, a novel non-invasive and non-ionizing biomedical imaging method, combines the high contrast of optical imaging with the deep penetration capability of ultrasound imaging (imaging depth up to approximately 3 cm subcutaneously), achieving high-resolution imaging of deep tissues. This dual-modal imaging strategy, combining the two, promises to achieve complementary advantages in imaging depth, sensitivity, and resolution, thereby providing more accurate boron drug distribution information for BNCT (Bore-Conduct-Nutritive Therapy). Although some fluorescent or photoacoustic probes have been reported, achieving efficient boron delivery and integrating fluorescence / photoacoustic dual-modal imaging into a single diagnostic and therapeutic boron drug delivery system still faces significant technical challenges. The challenges lie in two aspects: firstly, the lack of a suitable molecular framework that can accommodate high-density boron atoms and possess tunable optical properties; secondly, when integrating the boron-carrying unit with the chromophore, it is necessary to ensure that their biological distribution behavior in vivo is consistent and that they do not interfere with each other, which places extremely high demands on molecular design.
[0006] Therefore, developing a novel therapeutic boron drug that combines high boron-10 loading with fluorescence / photoacoustic dual-modal self-monitoring capabilities is of urgent need and significant importance for promoting the precision development and clinical translation of BNCT technology. Summary of the Invention
[0007] The technical problems to be solved by the present invention are: (1) overcoming the key bottleneck of limited boron loading in existing boron neutron capture therapy (BNCT); (2) providing a small molecule diagnostic and therapeutic reagent with a well-defined structure, good chemical stability and fluorescence / photoacoustic dual-modal imaging function, so as to realize real-time dynamic self-monitoring of boron concentration during BNCT treatment.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A high-boron-10 loading, therapeutic BODIPY boron drug, wherein the dual-modal imaging reagent structure is shown in general formula I:
[0010]
[0011] Preferably, the boron drug has dual-modal functionality of fluorescence imaging and photoacoustic imaging.
[0012] Preferably, the meso position of the BODIPY core is connected to a -CF3 group, and the molecule contains a borate ester ring formed by an ortho-dihydroxyl group and a boron atom of the BODIPY core.
[0013] Preferably, the ortho-dihydroxyl group in the borate ester ring is derived from the catechol structural unit.
[0014] Preferably, all boron atoms in the structure are boron-10 isotopes.
[0015] This invention also provides a method for preparing a high-boron-10 loading, therapeutically integrated BODIPY boron drug. The method includes the following reaction steps:
[0016] (1) Under a nitrogen atmosphere, trifluoroacetic acid and 2,4-dimethylpyrrole were dissolved in dichloromethane, and phenyltrichlorosilane was slowly added dropwise with stirring. Triethylamine was then added dropwise to the reaction system, and the reaction was continued with stirring. The reaction solution was treated with boron trifluoride-diethyl ether solution and then extracted with dichloromethane, retaining the organic phase. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The organic phase was then purified by silica gel column chromatography to obtain compound 3.
[0017]
[0018] (2) After mixing compound 4 and compound 5, dry toluene was used as solvent and the mixture was stirred and refluxed at 160°C; the reaction solution was cooled to room temperature and the solvent was evaporated by rotary evaporation; the mixture was purified by silica gel column chromatography to obtain compound 6.
[0019]
[0020] (3) Compound 3, compound 6, acetic acid and piperidine were dissolved in dry toluene and stirred under reflux. The reaction solution was cooled, extracted with dichloromethane, washed with saturated brine and dried with anhydrous magnesium sulfate, concentrated by rotary evaporation, and finally purified by silica gel column chromatography to obtain compound I.
[0021]
[0022] Further, in step (1), under nitrogen protection, trifluoroacetic acid, 2,4-dimethylpyrrole, and phenyltrichlorosilane (molar ratio 1:2:1) were dissolved in dichloromethane and reacted at room temperature for 3-6 hours. Subsequently, triethylamine with a molar ratio of 2:1 to 2,4-dimethylpyrrole was added dropwise, and stirring was continued at room temperature for 15 minutes. Then, a boron trifluoride diethyl ether solution with a molar ratio of 1.5:1 to triethylamine was added dropwise, and stirring was continued at room temperature for 3-10 hours after the addition was completed. After the reaction was completed, the crude product was obtained by extraction, drying, and concentration. Finally, the crude product was purified by silica gel column chromatography using a mixed solvent with a volume ratio of petroleum ether:dichloromethane = 1:1 as the eluent to obtain compound 3.
[0023] Further, in step (2), the molar ratio of compound 4 to compound 5 is 1:2; the stirring and reflux conditions are 160°C for 3-6 hours; and the volume ratio of eluent used in silica gel column chromatography is petroleum ether: dichloromethane = 5:1.
[0024] Further, in step (3), the molar ratio of compound 3 to compound 6 is 1:2, and acetic acid and piperidine are catalytic amounts; the stirring and reflux conditions are 110°C for 2-4 hours; the volume ratio of eluent used in silica gel column chromatography is petroleum ether: dichloromethane = 3:1.
[0025] This invention also provides the application of the high boron-10 loading therapeutic BODIPY boron drug in the preparation of a therapeutic drug for boron neutron capture therapy and fluorescence / photoacoustic dual-modal imaging.
[0026] The beneficial effects achieved by this invention are as follows:
[0027] 1. The small molecule diagnostic and therapeutic reagent based on the BODIPY core structure provided by this invention utilizes its inherent¹ 0 The boron atom acts as a neutron-capturing active center, and by utilizing the intramolecular dihydroxyl group to form a stable boron ester ring, the molecule itself becomes a highly efficient boron carrier, thereby improving the boron loading and structural stability of the drug.
[0028] 2. This design effectively modulates and enhances the intramolecular charge transfer effect by introducing a molecular skeleton with a clear D-π-A characteristic and precisely introducing a strong electron-withdrawing group -CF3 at the meso site, thereby achieving a redshift in the spectrum and obtaining better tissue penetration ability, providing an excellent signal basis for fluorescence / photoacoustic imaging.
[0029] 3. This invention integrates efficient boron carrying capacity with fluorescence / photoacoustic dual-modal imaging function, realizing real-time, non-invasive, high-resolution dynamic monitoring of boron drug distribution and precise treatment during BNCT. Attached Figure Description
[0030] Figure 1 This is a synthetic route diagram of the boron-rich diagnostic and therapeutic integrated reagent prepared in the embodiments of the present invention. Detailed Implementation
[0031] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.
[0032] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0033] Example 1: Synthesis of Compound 3
[0034] Under nitrogen protection, trifluoroacetic acid (1 mmol) and 2,4-dimethylpyrrole (2 mmol) were dissolved in dichloromethane (20 mL), followed by the dropwise addition of phenyltrichlorosilane (1 mmol). The mixture was stirred at room temperature for 4 hours. Triethylamine (4 mmol) was then added dropwise with stirring at room temperature for 15 minutes, followed by the addition of boron trifluoride diethyl ether solution (6 mmol) with stirring at room temperature for 3 hours. After the reaction was complete, the mixture was extracted with dichloromethane (50 mL), washed with water (100 mL × 3), and dried over anhydrous magnesium sulfate. After filtration and concentration, the crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane, 1:1, v / v) to give compound 3 (red solid, 21% yield).
[0035] 1H NMR spectroscopy analysis of compound 3 1 H NMR (400 MHz, CDCl3) δ 6.15 (s, 1H), 2.54 (s,3H), 2.30 (s, 2H).
[0036] Example 2: Synthesis of Compound 6
[0037] Compound 4 (1 mmol) and compound 5 (1 mmol) were mixed and dissolved in anhydrous toluene (20 ml), and the mixture was stirred and refluxed at 160 °C for 3–6 hours. The reaction mixture was cooled to room temperature, and the organic solvent was evaporated by rotary evaporation. The crude product was purified by silica gel column chromatography (petroleum ether: dichloromethane = 5:1) to give compound 6 (white solid, 10% yield).
[0038] 1H NMR spectroscopy analysis of compound 6 1 H NMR (500 MHz, Chloroform-d) δ 9.86 (s, 1H), 7.55 (dd, J = 8.2, 2.0 Hz, 1H), 7.25 (s, 1H), 6.94 (d, J = 8.3 Hz, 1H), 5.75 (s, 1H).
[0039] Example 3: Synthesis of Compound I (Target Boron Drug)
[0040] Compound 3 (1 mmol), compound 6 (2 mmol), acetic acid (1 mmol), and piperidine (1.5 mmol) were dissolved in anhydrous toluene (20 mL) and refluxed at 110 °C for 4 hours. After the reaction solution cooled to room temperature, it was extracted with dichloromethane (50 mL), the organic phase was washed with water (100 mL × 3), and dried over anhydrous magnesium sulfate. After filtration and concentration, the crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 3:1, v / v) to give compound I (using natural boron as the starting material).
[0041] 1H NMR spectroscopy analysis of compound I 1 H NMR (500 MHz, Chloroform-d) δ 7.89 – 7.77(m, 2H), 7.61 – 7.49 (m, 1H), 7.42 – 7.35 (m, 1H), 7.07 (dd, J = 14.1, 0.7Hz, 1H), 6.96 (d, J = 8.0 Hz, 1H), 6.92 – 6.85 (m, 1H), 6.58 (s, 1H), 5.73(s, 1H), 4.74 (s, 1H), 2.69 (d, J = 1.3 Hz, 2H).
[0042] Example 4: Synthesis of Compound I' (Target Boron Drug, Boron-10 Isotope)
[0043] The synthetic route and steps were exactly the same as in Example 3, the only difference being that all boron-containing raw materials used, including the boron trifluoride-diethyl ether solution required for the synthesis of compound 3, were replaced with boron-10-rich raw materials. 10 B) The corresponding raw materials of isotopes (abundance > 99%).
[0044] The final product was compound I' (the target product with high boron-10 loading). Mass spectrometry (MS) analysis confirmed that its molecular weight was consistent with the theoretical value.
[0045] Example 5: Photophysical properties and in vitro imaging tests of compound I
[0046] Prepare a PBS solution from compound I (or I') obtained in Example 3 or Example 4.
[0047] Ultraviolet-visible-near-infrared absorption spectroscopy measurements showed that its maximum absorption wavelength (λ) abs It is located at 680 nm.
[0048] Fluorescence spectroscopy measurements showed that its maximum emission wavelength (λ) em The wavelength is located at 710 nm, which proves that it has near-infrared fluorescence imaging capability.
[0049] Photoacoustic imaging tests showed that the solution produced a strong photoacoustic signal under 680 nm laser excitation, proving that it has photoacoustic imaging capabilities.
[0050] Example 6: Preliminary study of in vivo dual-modal imaging of compound I and the efficacy of BNCT.
[0051] Experiments were conducted in a tumor-bearing mouse model:
[0052] In vivo distribution monitoring: Following tail vein injection of compound I', scans were performed at different time points using a small animal fluorescence imaging system and a small animal photoacoustic imaging system. Results showed that the compound specifically accumulated at the tumor site, and its metabolic dynamics could be monitored in real-time and non-invasively.
[0053] BNCT treatment: When photoacoustic signals indicate that the drug concentration within the tumor has reached its peak (e.g., 24 hours after injection), the tumor site is irradiated with thermal neutrons. Compared with the control group, tumor growth in the treated mice was significantly inhibited, demonstrating the effectiveness of BNCT.
[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A high-boron-10 loading, therapeutically integrated BODIPY boron drug, characterized in that, Its structure is shown in general formula I: 。 2. The high boron-10 loading, therapeutically integrated BODIPY boron drug according to claim 1, characterized in that, The boron drug has dual-modal capabilities for both fluorescence imaging and photoacoustic imaging.
3. The high boron-10 loading, therapeutically integrated BODIPY boron drug according to claim 1, characterized in that, The BODIPY core has a -CF3 group attached to its meso position, and the molecule contains a borate ester ring formed by an ortho-dihydroxyl group and a boron atom in the BODIPY core.
4. The high boron-10 loading, therapeutically integrated BODIPY boron drug according to claim 3, characterized in that, The ortho-dihydroxyl group in the borate ester ring is derived from the catechol structural unit.
5. The high boron-10 loading, therapeutically integrated BODIPY boron drug according to claim 1, characterized in that, All boron atoms in the structure are boron-10 isotopes.
6. A method for preparing a high-boron-10 loading, therapeutically integrated BODIPY boron drug as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Under a nitrogen atmosphere, trifluoroacetic acid and 2,4-dimethylpyrrole were dissolved in dichloromethane, and phenyltrichlorosilane was slowly added dropwise under stirring. Triethylamine was then added dropwise to the reaction system, and the reaction was continued with stirring. The reaction solution was treated with boron trifluoride-diethyl ether solution and then extracted with dichloromethane to retain the organic phase. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The organic phase was then purified by silica gel column chromatography to obtain compound 3. (2) After mixing compound 4 and compound 5, dry toluene was used as solvent and the mixture was stirred and refluxed at 160°C; the reaction solution was cooled to room temperature and the solvent was evaporated by rotary evaporation; the mixture was purified by silica gel column chromatography to obtain compound 6. (3) Compound 3, compound 6, acetic acid and piperidine were dissolved in dry toluene and stirred under reflux. The reaction solution was cooled, extracted with dichloromethane, washed with saturated brine and dried with anhydrous magnesium sulfate, concentrated by rotary evaporation, and finally purified by silica gel column chromatography to obtain compound I.
7. The preparation method according to claim 6, characterized in that, In step (1), the molar ratio of trifluoroacetic acid, 2,4-dimethylpyrrole, and phenyltrichlorosilane is 1:2:1, and the reaction is carried out at room temperature for 3-6 hours. Subsequently, triethylamine is added in a molar ratio of 2:1 to 2,4-dimethylpyrrole, and the mixture is stirred at room temperature for 15 minutes. Then, boron trifluoride diethyl ether solution is added in a molar ratio of 1.5:1 to triethylamine, and the reaction is carried out at room temperature for 3-10 hours. The crude product is purified by silica gel column chromatography using a mixed solvent with a volume ratio of petroleum ether:dichloromethane = 1:1 as the eluent.
8. The preparation method according to claim 6, characterized in that, In step (2), the molar ratio of compound 4 to compound 5 is 1:1; the stirring and reflux conditions are 160℃ for 3-6 hours; the volume ratio of eluent used in silica gel column chromatography is petroleum ether: dichloromethane = 5:
1.
9. The preparation method according to claim 6, characterized in that, In step (3), the molar ratio of compound 3 to compound 6 is 1:2, and acetic acid and piperidine are the catalytic amounts; the stirring and reflux conditions are 110℃ for 2-4 hours; the volume ratio of eluent used in silica gel column chromatography is petroleum ether: dichloromethane = 3:
1.
10. The use of the high boron-10 loading therapeutic BODIPY boron drug according to any one of claims 1-5 in the preparation of a therapeutic drug for boron neutron capture therapy and fluorescence / photoacoustic dual-modal imaging.