Patent Description:
In recent years, local, minimally invasive radioactive treatment has played an increasingly important role in clinical treatment, and has been more and more widely used especially in the treatment of unresectable liver cancer, prostate cancer, kidney cancer and other solid tumors.

Currently, the radioactive microsphere products for local, minimally invasive radioactive treatment of advanced liver cancer in clinic mainly include yttrium [<NUM>Y] resin microspheres SIR-Spheres® (Sirtex Medical Limited, Australia) and yttrium [<NUM>Y] glass microspheres TheraSphere®(BTG, UK). Because the radioactive yttrium [<NUM>Y] nuclide is a pure beta nuclide, it can only generate gamma rays for imaging through bremsstrahlung, so only blurred images (as shown in <FIG>) are available in single photon emission computed tomography (SPECT) and positron emission tomography (PET), and in vivo distribution data of the radioactive microspheres and changes in the lesion site cannot be accurately obtained. Therefore, both yttrium [<NUM>Y] resin microspheres and yttrium [<NUM>Y] glass microspheres can only provide low-quality SPECT and PET images, which are difficult to provide significant and clear-image visualization functions for diagnosis and treatment. Once such radioactive microspheres have entered the lesion site, the following can only be assessed by other imaging techniques: <NUM>. whether the agent has entered the target position accurately; <NUM>. whether the radioactive microspheres have moved into other tissues and organs during the treatment; and <NUM>. evaluation of the therapeutic effect for the treatment site. However, these imaging techniques usually only achieve short-term imaging, and a contrast agent and a therapeutic agent are two different agents or entities, and there are at least the following two problems: <NUM>. the contrast agent needs to be administrated separately to achieve imaging, which brings great inconvenience to clinical use; and <NUM>. the distribution and metabolic behavior of the contrast agent and the radioactive microspheres in the body are inconsistent, and the location of the radioactive microspheres cannot be accurately monitored for a long time.

Therefore, in order to realize the visualization of the entire administration process, accurately monitor the in vivo distribution of the radioactive therapeutic microspheres during the treatment process, and efficiently evaluate the therapeutic efficacy, the realization of high-quality visualization of the radioactive therapeutic microspheres is an issue which urgently needs to be addressed in the art. In the relevant state of the art, document <CIT> gives an example of simple carbon microspheres carrying <NUM> yttrium as therapeutic radionuclide. Document <CIT> also suggests carbon microspheres of medical yttrium phosphate <NUM>Y<NUM>PO<NUM> as a tumor radiotherapy medicament. The interest of radiolabeling for image and therapy has been suggested in document <CIT>. The latter suggests to complex a macromolecule composition with different FibrinLite compositions which are prepared with two different isotopes. G Ferro-Flores ET AL have also suggested carbon nanoparticles with an imaging and a therapeutic radionuclide in the article "Multifunctional Radiolabeled Nanoparticles for Targeted Therapy", Current Medicinal Chemistry, Vol. <NUM>, (<NUM>-<NUM>-<NUM>), pages <NUM>-<NUM>.

In order to solve the problems in the background art and realize the visualized treatment of radioactive carbon microsphere products in the tumor treatment process, the present invention provides a visualized radioactive carbon microsphere suspension and a preparation method thereof. The carbon microsphere suspension has the characteristics of being clearly visible under PET and available for quantitative analysis, which enables visualization of the radiation therapy process in solid tumors without the aid of other contrast agents.

According to the technical solutions provided by the present invention, the visualized radioactive carbon microsphere suspension is radioactive carbon microspheres with high-energy beta-ray emission for solid tumor treatment and PET imaging, made by loading carbon microspheres having good biocompatibility with radioactive nuclides for treatment and zirconium [<NUM>Zr] and dispersing into a special solution.

To achieve the above objectives, the first technical solution adopted by the present invention is:
a visualized radioactive carbon microsphere suspension, every <NUM> of the solution comprising: <NUM>-<NUM> of carbon microspheres, <NUM>-<NUM> mCi of activity of radioactive nuclides for treatment, <NUM>-<NUM> mCi of activity of radioactive nuclides for imaging, <NUM>-<NUM> of small organic molecules, and <NUM>-<NUM> of a first solution.

Further, the carbon microspheres are spherical or non-spherical carbon materials rich in micropores and mesopores prepared by any method, with a diameter of <NUM>-<NUM>, preferably <NUM>-<NUM>. The visualized carbon microsphere products prepared from carbon microspheres with different particle sizes can be used for visualized treatment of different solid tumor lesions due to different administration modes and different distributions in tissues, organs and lesions.

Further, the small organic molecule is <NUM>-sulfosalicylic acid, <NUM>-nitrosalicylic acid or a small molecule with a similar structure obtained by simple chemical modification.

Further, the radioactive nuclide for treatment is selected from any one of yttrium [<NUM>Y], lutetium [<NUM>Lu], holmium [<NUM>Ho], samarium [<NUM>Sm] and isotopes thereof, and the radioactive nuclide for imaging is zirconium [<NUM>Zr],.

Further, the first solution comprises, but is not limited to, an ethanol solution, a polyethylene glycol solution, and a glycerin solution; water-soluble carbohydrate solutions such as a glucose solution, a dextran solution, and a glucan solution; water-soluble cellulose solutions such as a sodium carboxymethyl cellulose solution, a sodium carboxyethyl cellulose solution, and a hydroxypropyl cellulose solution; water-soluble starch solutions such as a hydroxyethyl starch solution and a sodium carboxymethyl starch solution; and other water-soluble small-molecule or polymer solutions with similar structures.

Further, the radioactive nuclides for treatment and zirconium [<NUM>Zr] are water-soluble radioactive nuclides for treatment and zirconium [<NUM>Zr] in different chemical forms prepared by generators or nuclear reactors or any other common preparation methods. The radioactivity of the solution of radioactive nuclides for treatment is <NUM> mCi-<NUM> Ci, and the radioactivity of the solution of radioactive zirconium [<NUM>Zr] is <NUM> mCi-<NUM> Ci.

The second technical solution adopted by the present invention is:
a method for preparing the visualized radioactive carbon microsphere suspension, the method comprising the following steps:.

The third technical solution adopted by the present invention is:
a method for preparing the visualized radioactive carbon microsphere suspension, the method comprising the following steps:.

Further, the first pH value is <NUM>-<NUM>, preferably <NUM>-<NUM>; and the second pH value is <NUM>-<NUM>, preferably <NUM>-<NUM>.

The present invention also provides a use of the aforementioned visualized radioactive carbon microsphere suspension for preparing an agent for visualized tumor treatment, wherein the tumor comprises, but is not limited to solid tumors including liver cancer, pancreatic cancer, renal cancer, breast cancer, thyroid cancer and intestinal cancer, and orthopedic tumors.

Further, the visualized tumor treatment is to simultaneously realize local radioactive treatment and real-time imaging of tumor lesions, and the imaging means is PET/CT.

The present invention is made by with carbon microspheres having good biocompatibility as carriers, dispersing carbon microspheres loaded with radioactive nuclides for treatment and zirconium [<NUM>Zr] into a special solution, can realize uniform distribution in tumor tissues through catheter intervention, injection and other administration means, and can carry out tumor implantation for various solid tumors, including liver cancer, pancreatic cancer, kidney cancer, breast cancer, thyroid cancer, intestinal cancer and other solid tumors, to achieve visualized brachytherapy.

The visualized carbon microspheres of the present invention are mainly used for the treatment of solid tumors and visualized treatment by positron emission tomography-computed tomography (PET/CT) during the treatment process, and are simultaneously used as an agent for treatment and an agent for imaging. The visualized carbon microspheres can enter into tumors by means of injection, intervention, etc., to achieve the killing of tumor cells by emitting high-energy beta rays by radioactive nuclides for treatment, and to achieve imaging by collecting positrons emitted by zirconium [<NUM>Zr] by PET, thereby realizing the visualized treatment of tumor lesions.

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

In order to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described below with reference to the accompanying drawings and examples. Modes for implementing the present invention include, but are not limited to, the following examples, which are used to illustrate the present invention, and are not intended to limit the protection scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. The test methods in the following examples are conventional methods unless otherwise specified.

The methods for determining the labeling rate and release rate of a radioactive nuclide used in the examples of the present invention are as follows:.

Considering the correction of each sampling loss, the total activity of radioactive nuclides A(ti) of the soaking solution measured at the i-th time is calculated according to the formula (<NUM>): <MAT>.

A visualized radioactive carbon microsphere suspension, every <NUM> of the solution comprising: <NUM>-<NUM> of carbon microspheres, <NUM>-<NUM> mCi of activity of radioactive nuclides for treatment, <NUM>-<NUM> mCi of activity of radioactive zirconium [<NUM>Zr], <NUM>-<NUM> of small organic molecules, and <NUM>-<NUM> of a first solution.

Specifically, the carbon microspheres are spherical or non-spherical carbon materials rich in micropores and mesopores prepared by any method, with a diameter of <NUM>-<NUM>, preferably <NUM>-<NUM>. The visualized carbon microsphere products prepared from carbon microspheres with different particle sizes can be used for visualized treatment of different solid tumor lesions due to different administration modes and different distributions in tissues, organs and lesions.

Specifically, the small organic molecule is <NUM>-sulfosalicylic acid, <NUM>-nitrosalicylic acid or a small molecule with a similar structure obtained by simple chemical modification.

Specifically, the first solution comprises, but is not limited to, an ethanol solution, a polyethylene glycol solution, and a glycerin solution; water-soluble carbohydrate solutions such as a glucose solution, a dextran solution, and a glucan solution; water-soluble cellulose solutions such as a sodium carboxymethyl cellulose solution, a sodium carboxyethyl cellulose solution, and a hydroxypropyl cellulose solution; water-soluble starch solutions such as a hydroxyethyl starch solution and a sodium carboxymethyl starch solution; and one or more of other water-soluble small-molecule or polymer solutions with similar structures.

Specifically, the radioactive nuclide for treatment is any one of yttrium [<NUM>Y], lutetium [<NUM>Lu], holmium [<NUM>Ho], samarium [<NUM>Sm] and isotopes thereof. The radioactive nuclides for treatment and zirconium [<NUM>Zr] both are water-soluble radioactive nuclides for treatment and zirconium [<NUM>Zr] in different chemical forms prepared by generators or nuclear reactors or any other common preparation methods. The radioactivity of the solution of radioactive nuclides for treatment is <NUM> mCi-<NUM> Ci, and the radioactivity of the solution of radioactive zirconium [<NUM>Zr] for imaging is <NUM> mCi-<NUM> Ci.

A method for preparing the visualized radioactive carbon microsphere suspension, the method comprising the following steps:.

Use of a visualized radioactive carbon microsphere suspension for preparing an agent for visualized treatment of solid tumors. The present invention is made by with carbon microspheres having good biocompatibility as carriers, dispersing carbon microspheres loaded with radioactive nuclides for treatment and the nuclide for imaging, zirconium [<NUM>Zr] into a special solution, can realize uniform distribution in tumor tissues through catheter intervention, injection and other administration means, and can carry out tumor implantation for various solid tumors, including liver cancer, pancreatic cancer, kidney cancer, breast cancer, thyroid cancer, intestinal cancer and other solid tumors, to achieve visualized brachytherapy.

Use of a visualized radioactive carbon microsphere suspension for preparing an agent for PET/CT. The visualized carbon microspheres of the present invention are mainly used for the treatment of solid tumors and visualized treatment by positron emission tomography-computed tomography (PET/CT) during the treatment process, and are simultaneously used as an agent for treatment and an agent for imaging. The visualized carbon microspheres can enter into tumors by means of injection, intervention, etc., to achieve the killing of tumor cells by emitting high-energy beta rays by radioactive nuclides for treatment, and to achieve imaging by collecting positrons emitted by zirconium [<NUM>Zr] by PET, thereby realizing the visualized treatment of tumor lesions.

A visualized radioactive carbon microsphere suspension, the preparation method of which comprising:.

<NUM>-<NUM> of a sodium carboxymethyl cellulose solution with a molar concentration of <NUM>% was added to the second intermediate, and they were mixed uniformly, dispensed into vials, and sterilized under the conditions of <NUM> and <NUM> to obtain a visualized carbon microsphere suspension available for injection.

The adsorption rate of the radioactive nuclides in the sample of this example is <NUM>%, and the release rate is <NUM>%.

The scanning electron micrographs of the prepared visualized radioactive carbon microspheres are shown in <FIG>. The particle size of the microspheres is mainly <NUM>-<NUM>, and the surface is smooth.

The efficacy evaluation was carried out by in situ tumor injection of the visualized carbon microsphere suspension of Example <NUM> of the present application in an xenograft model on the body surface of New Zealand rabbits:.

Ultrasound observation and size measurement after <NUM> days of treatment showed that the tumors of <NUM> New Zealand rabbits in the experimental group did not grow, while the tumors of <NUM> New Zealand rabbits in the control group increased significantly in volume. Local anatomy of the New Zealand rabbits was performed after <NUM> days of treatment. The local anatomy of <NUM> rabbits in the experimental group is shown in <FIG>. Through anatomy, it is obviously observed that black visualized carbon microspheres are locally visible in the tumor tissues of the <NUM> New Zealand rabbits at the administration site, and it can be seen that the tumor tissues near the visualized carbon microspheres become grayish brown, with obvious fibrosis and necrosis. It is proved that the visualized carbon microsphere suspension prepared in the examples of the present application exhibits good antitumor activity.

The visualized carbon microsphere suspension of Example <NUM> of the present application was administered to New Zealand rabbits through hepatic artery catheterization surgery, and the distribution of the visualized carbon microsphere suspension in animals was studied: The dosage of a single New Zealand rabbit was about <NUM>, and PET scans on whole body of the rabbits in different beds was performed at six time points of <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> after administration of the visualized radioactive carbon microsphere suspension, and while maintaining the animals stationary, CT scans were done before/after PET scans. The results are shown in <FIG>.

After the PET/CT scans were completed, image reconstruction was performed, and PMOD software was used to process the images and data. Organs such as brain, heart, liver, spleen, lungs, kidneys, stomach, bones, and muscles were outlined as regions of interest, and the radioactivity concentrations (namely, radioactivity value per unit volume) in the regions of interest were obtained. Then, the decay correction was performed on the activity at each time point. The results are shown in Table <NUM>. The formulas used are as follows: <MAT> <MAT>
<IMG>.

A clear distribution image of visualized carbon microspheres in animals is obtained in <FIG>. Combining with the data on uptake in each organ and tissue in Table <NUM>, it can be seen that the visualized carbon microspheres are concentrated in the liver, accounting for more than <NUM>%, with small uptake in other organs and tissues.

Claim 1:
A visualized radioactive carbon microsphere suspension, every <NUM> of the solution comprising: <NUM>-<NUM> of carbon microspheres, <NUM>-<NUM> mCi of activity of radioactive nuclides for treatment, <NUM>-<NUM> mCi of activity of radioactive nuclides for imaging, <NUM>-<NUM> of small organic molecules, and <NUM>-<NUM> of a first solution, and wherein the radioactive nuclide for treatment is selected from any one of yttrium [<NUM>Y], lutetium [<NUM>Lu], holmium [<NUM>Ho], samarium [<NUM>Sm] and isotopes thereof, the radioactive nuclide for imaging is zirconium [<NUM>Zr], and the small organic molecules is <NUM>-sulfosalicylic acid or <NUM>-nitrosalicylic acid.