Hepatophilic yttrium 90 radioactive microsphere and preparation method thereof

Abstract

The invention relates to a hepatophilic yttrium 90 radioactive microsphere and a preparation method thereof, and belongs to the technical field of biological medicines. The invention provides a hepatophilic yttrium 90 radioactive microsphere. The radioactive microsphere is internally provided with an EOB-chelating agent and 90Y, the chelating agent is DTPA (diethylenetriamine pentaacetic acid); fat-soluble EOB added on the molecular structure of the chelating agent DTPA in the EOB-DTPA is combined with a hepatocyte surface receptor, so that the EOB-DTPA has hepatocyte-friendly specificity. The chelating agent DTPA is chelated with the yttrium 90, so that the stability of the yttrium 90 in the microspheres is improved; through the form of EOB-DTPA-90Y, the retention time of 90Y in the liver is prolonged, so that 90Y is retained in the liver as far as possible in a half-life period, the curative effect of a radioactive drug is improved, and the administration dosage of the radioactive drug is reduced.

Description

Technical Field

[0001] The invention relates to hepatocyte-tropic yttrium-90 radioactive microspheres and a preparation method thereof, belonging to the technical field of biomedicine. Background Art

[0002] Globally, the incidence of liver cancer is increasing year by year. my country accounts for more than 50% of the world's new liver cancer patients each year. Liver cancer has become the most lethal type of malignant tumor in my country. The main treatment methods for liver cancer are surgical resection, chemotherapy, external irradiation therapy and transarterial radioembolization. Less than 10% of primary liver cancer and less than 5% of metastatic liver cancer are suitable for surgical treatment; the liver is very sensitive to radioactive rays, but external irradiation therapy can cause damage to normal tissues of the liver and other organs; traditional chemotherapy has shortcomings such as poor therapeutic effects and large side effects. Transarterial radioembolization (TARE) is a method of perfusing radioactive microspheres of a specific particle size through a catheter inserted into the target artery under X-ray fluoroscopy. The microspheres can reach the tumor site with the help of blood flow and embolize in the capillary bed of the tumor. On the one hand, the radioactive microspheres can block the blood supply to the tumor, making the tumor lack the necessary nutrient supply; on the other hand, they can provide dose deposition at the tumor site, remove tumor cells through radiation, and the normal tissue is exposed to a very small dose. Transarterial radioembolization has a very significant therapeutic effect on primary and metastatic liver cancer, and has become one of the main radioactive implantation treatment methods in Europe and the United States. Currently, there are two types of radioactive microspheres approved for commercial use by the U.S. Food and Drug Administration (FDA): 90Y glass microspheres and 90Y resin microspheres. 166 Ho polylactic acid microspheres. 90Y glass microspheres have the advantages of stable performance, good spheroidization, non-toxicity, high radioactivity per microsphere, and a small number of microspheres required for treatment. They can also reduce the incidence of ectopic embolism caused by reflux. However, yttrium 90 glass microspheres need to be produced through neutron activation in nuclear reactors, which is costly; while the radionuclide dissolution rate of yttrium 90 resin microspheres is high, and the detached yttrium 90 ions easily enter the blood circulation, causing serious adverse reactions such as bone marrow suppression and pulmonary fibrosis. This is mainly because yttrium 90 is exchanged into the cationic resin and there is no stable complexation by chemical force. The half-life of yttrium 90 is 64 hours. Over time, the radiation intensity will gradually weaken. Generally speaking, over 8 days, 87% of the radiation will be released; after 14 days, the radiation release rate can reach more than 95%. In clinical practice, it is found that radioactive microspheres infused through the hepatic artery quickly enter the lungs after 2 hours, that is, not all yttrium-90 microspheres are retained in the liver during the half-life, and the loss of radioactive microspheres leads to reduced drug efficacy. Therefore, the technical field urgently needs to obtain a hepatocyte-friendly yttrium-90 radioactive microsphere to make the drug stay in the liver longer, so as to achieve the purpose of using as little drug as possible to obtain the same therapeutic effect and meet the needs of the field of liver cancer treatment. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problem of how to obtain hepatocellular Y-90 radioactive microspheres to achieve a longer drug retention time in the liver.

[0004] In order to achieve the purpose of solving the above problems, the technical solution adopted by the present invention is to provide a hepatocellular yttrium 90 radioactive microsphere, wherein the radioactive microsphere is provided with an EOB-chelating agent and 90 Y.

[0005] Preferably, the chelating agent is DTPA; the radioactive microspheres are provided with EOB-DTPA- 90 Y.

[0006] The present invention provides a method for preparing hepatocellular yttrium-90 radioactive microspheres, the preparation method comprising:

[0007] Step 1: preparing an organic phase solution of a degradable polymer in an organic solvent;

[0008] Step 2: preparing an aqueous solution; adding a porogen into the aqueous solution;

[0009] Step 3: Mixing the organic phase solution with the aqueous phase solution to prepare droplets, adjusting the pH to acidic, removing the organic solvent, and separating to obtain degradable microspheres;

[0010] Step 4: Screen the microspheres and add an ethanol solution containing an extractant, then remove the ethanol to obtain microspheres doped with the extractant; add 90 YCl3 solution, oscillate in a water bath to complete labeling; acid wash the labeled microspheres;

[0011] Step 5: Dissolve EOB-DTPA in dimethyl sulfoxide (DMSO); 90 Y biodegradable microspheres were added to DMSO solution, soaked and filtered to obtain EOB-DTPA- 90 Y biodegradable microspheres.

[0012] Preferably, in step 1, the degradable polymer is at least one of poly (L-lactic acid), polycaprolactone, poly (lactic acid-glycolic acid), microbial polyester, and aliphatic polyester, and the organic solvent is at least one of dichloromethane, chloroform, and ethyl acetate.

[0013] Preferably, the porogen in step 2 is (NH4)2CO3, NH4HCO3 or NaHCO3.

[0014] Preferably, the extractant in step 4 is a phosphate extractant.

[0015] Preferably, in step 4, the microspheres are screened to obtain microspheres of 300 to 600 meshes.

[0016] Preferably, the preparation method of the droplets in step 3 includes an emulsification solvent evaporation method, a vacuum drying method, and a droplet microfluidics method.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The EOB-DTPA- 90 Y-degradable microspheres, through the lipid-soluble ethoxybenzyl (EOB) added to the molecular structure of the chelating agent DTPA in EOB-DTPA, bind to the surface receptors of liver cells, making EOB-DTPA specific to liver cells. The chelating agent DTPA then chelates with yttrium 90 to increase the stability of yttrium 90 in the microspheres; through EOB-DTPA- 90 Y form, increase 90 Y stays in the liver for a long time, 90 Y is retained in the liver as much as possible during its half-life, thereby improving the efficacy of radiopharmaceuticals and reducing the dosage of radiopharmaceuticals. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 EOB-DTPA- 90 Schematic diagram of the structure of Y. DETAILED DESCRIPTION

[0020] In order to make the present invention more clearly understood, the preferred embodiments and the accompanying drawings are described in detail as follows:

[0021] Example 1

[0022] Preparation process of hepatocellular Y-90 radioactive microspheres:

[0023] Step 1: Weigh 1 g of L-polylactic acid (with an intrinsic viscosity of 0.9 dl / g) in a flask, add 20 ml of dichloromethane, stir and dissolve to obtain an organic phase solution.

[0024] Step 2: Weigh 20.4 g of gelatin and dissolve it in 800 ml of 90°C hot water. After the hot water cools, dilute the volume to 1000 ml to obtain a 2% aqueous solution.

[0025] Step 3: Take 200 ml of the aqueous solution obtained in step 2, add 0.5 g NH4HCO3, stir to dissolve; add to the organic phase solution under stirring; set the stirring speed to 1500 rpm, magnetically stir for 10 minutes, transfer to a 30°C constant temperature water bath after emulsification, add 10 ml of 5% acetic acid solution, continue to stir at 800 rpm in the open until the organic solvent is completely evaporated, and wait for the polylactic acid to solidify into balls.

[0026] Step 4: The obtained polylactic acid porous microspheres were centrifuged at 2000 rpm for 2 min, washed with water and centrifuged repeatedly for 3 times to remove the emulsifier, and dried in a vacuum drying oven at 40° C. for 24 h.

[0027] Step 5: The collected microspheres were sieved with a negative pressure sieve (upper 300 mesh, lower 600 mesh), and 100 mg of the sieved polylactic acid porous microspheres were weighed;

[0028] Step 6: Take 20 μl of diisooctyl phosphate (P204) and add it to 20 ml of anhydrous ethanol, then take 2 ml and add it to the polylactic acid porous microspheres, stir evenly and dry in a vacuum drying oven at 40°C for 48 hours.

[0029] Step 7: Soak the polylactic acid porous microspheres doped with P204 in 0.01M HCl for 24 hours and filter them. Transfer the microspheres to a conical flask and add 0.01M HCl. 90 20 ml of YCl3 solution (specific activity 0.01 Ci / ml) was shaken in a constant temperature water bath shaker at 45°C for 4 h.

[0030] Step 8: After labeling, filter and wash twice with 0.01M HCl to obtain 90 Y biodegradable microspheres.

[0031] Step 9: Take 2 mg EOB-DTPA and dissolve it in 50 μl dimethyl sulfoxide (DMSO); take 50 μl DMSO, add 300 μl polyethylene glycol PEG300 and mix until clear, then add 50 μl Tween 80 and mix until clear, then add 600 μl ddH2O and mix until clear;

[0032] Step 10: 90 Y biodegradable microspheres were added to the solution of step 9, and filtered after soaking for 24 hours, and washed twice with 0.01M HCl to obtain EOB-DTPA- 90 Y biodegradable microspheres.

[0033] The chemical reagents used in the above preparation process are commercially available materials.

[0034] The biodegradable polymer poly(L-lactic acid) is used as the microsphere matrix material, making the microspheres biodegradable and allowing patients to use them multiple times. 90Y-degradable microspheres improve the therapeutic effect of diseases. The extractant dioctyl phosphate (P204) is added to the prepared microspheres to improve the adsorption effect and adsorption rate of yttrium-90, thereby reducing the labeling time and improving the labeling effect. The post-labeling method is used to label yttrium-90 on the microspheres, avoiding the problem of microspheres being damaged after irradiation; Figure 1 As shown in the figure, the chelating agent DTPA in EOB-DTPA has a fat-soluble ethoxybenzyl (EOB) added to its molecular structure. EOB can bind to the surface receptors of liver cells, making EOB-DTPA specific to liver cells. The chelating agent DTPA is then chelated with yttrium 90 to increase the stability of yttrium 90 in the microspheres; 90 Y form, increase 90 Y stays in the liver for a long time, 90 Y stays in the liver as much as possible during its half-life, improving drug efficacy and reducing dosage.

[0035] Example 2

[0036] EOB-DTPA- 90 Distribution of Y-degradable microspheres in animal tissues.

[0037] Drug: The radioactive microspheres provided in Example 1.

[0038] Experimental animals: New Zealand white rabbits, normal grade, male; body weight: 2.5-3.5 kg.

[0039] Experimental methods:

[0040] (1) Establishing tumor model

[0041] A VX2 rabbit liver transplant cancer model was established using New Zealand white rabbits. A 2mm diameter VX2 tumor mass was moved to the lower edge of the rabbit liver. A CT scan was performed 7 days later to record the location and size of the tumor mass. The model was successfully established when the maximum diameter of the tumor reached 1-2cm.

[0042] (2) Grouped medication

[0043] Animals were anesthetized before surgery (2.5% sodium pentobarbital, 30 mg / kg). The animal's groin was shaved, the groin skin was cut open, and the femoral artery was bluntly separated; the femoral artery was punctured under direct vision, and a 5F arterial sheath was inserted, and the femoral artery and arterial sheath were fixed with medical absorbable sutures. Under the guidance of a digital subtraction angiography (DSA), a 2.7F microcatheter was inserted into the common hepatic artery, and radioactive microspheres were injected through the microcatheter to avoid microsphere reflux as much as possible. After the embolization was completed, the catheter and arterial sheath were pulled out, and the femoral artery was ligated above the puncture site.

[0044] The rabbits were randomly divided into two groups, each with 3 rabbits. The two groups were injected with EOB-DTPA- 90 Y degradable microspheres (this group is used as the experimental group) and the microspheres obtained in step 8 of Example 1 90 Y degradable microspheres (this group served as the control group);

[0045] After the 1GBq radioactive microspheres were placed and decayed, the same number of microspheres were perfused into the livers of the experimental and control animals. The animals were killed 2 hours later, and after dissection, the liver and lung tissues were fixed with formalin, embedded in paraffin, sliced, stained with hematoxylin and eosin, and pathologically examined to observe the distribution and density of the microspheres.

[0046] Observation results: The distribution density of microspheres in the lungs of the experimental group was significantly less than that in the control group; the distribution density of microspheres in the liver of the experimental group was significantly more than that in the control group; the results showed that EOB-DTPA- 90 The retention time of Y-degradable microspheres in the liver was improved.

[0047] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and equivalent changes made by using the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A hepatocellular Y-90 radioactive microsphere, characterized in that: The radioactive microspheres are provided with EOB-chelating agent and 90 Y.

2. The hepatocellular Y-90 radiative microspheres according to claim 1, characterized in that: The chelating agent is DTPA.

3. A method for preparing hepatocellular Y-90 radioactive microspheres, characterized in that: The preparation method comprises: Step 1: preparing an organic phase solution of a degradable polymer in an organic solvent; Step 2: preparing an aqueous solution; adding a porogen into the aqueous solution; Step 3: Mix the organic phase solution with the aqueous phase solution to prepare droplets, adjust the pH to acidic, remove the organic solvent, and separate to obtain microspheres; Step 4: Screen the microspheres and add an ethanol solution containing an extractant, then remove the ethanol to obtain microspheres doped with the extractant; add 90 YCl3 solution, oscillate in a water bath to complete labeling; acid wash the labeled microspheres; Step 5: Dissolve EOB-DTPA in dimethyl sulfoxide (DMSO); 90 Y biodegradable microspheres were added to DMSO solution, soaked and filtered to obtain EOB-DTPA- 90 Y biodegradable microspheres.

4. The method for preparing hepatocellular Y-90 radioactive microspheres according to claim 3, characterized in that: In step 1, the degradable polymer is at least one of poly(lactic acid), polycaprolactone, poly(lactic acid-glycolic acid), microbial polyester, and aliphatic polyester, and the organic solvent is at least one of dichloromethane, chloroform, and ethyl acetate.

5. The method for preparing hepatocellular Y-90 radioactive microspheres according to claim 3, characterized in that: The porogen in step 2 is (NH4)2CO3, NH4HCO3 or NaHCO3.

6. The method for preparing hepatocellular Y-90 radioactive microspheres according to claim 3, characterized in that: The extractant in step 4 is a phosphate extractant, and the selection of the extractant includes using diisooctyl phosphate P204.

7. The method for preparing hepatocellular Y-90 radioactive microspheres according to claim 3, characterized in that: In the step 4, the microspheres are screened to obtain microspheres of 300 to 600 meshes.

8. The method for preparing hepatocellular Y-90 radioactive microspheres according to claim 3, characterized in that: The preparation method of the droplets in step 3 includes an emulsification solvent volatilization method, a vacuum drying method, and a droplet microfluidics method.

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