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Polymer based radionuclide containing particulate material

a radionuclide and polymer technology, applied in the field of polymer and radionuclide, can solve the problems of slow and continuous radiation delivery, excessive radiation in the focal area, and uneven distribution of radiation in the target organ

Inactive Publication Date: 2007-11-01
SIRTEX MEDICAL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Secondly, the radiation is slowly and continually delivered as the radionuclide decays.
If the microspheres or small particles do not distribute evenly, and as a function of the absolute arterial blood flow, then they may accumulate in excessive numbers in some areas and cause focal areas of excessive radiation.
If the particles are too dense or heavy, then they will not distribute evenly in the target organ and will accumulate in excessive concentrations in areas that do not contain the cancer.
It has been shown that solid, heavy microspheres distribute poorly within the parenchyma of the liver when injected into the arterial supply of the liver.
This, in turn, decreases the effective radiation reaching the cancer in the target organ, which decreases the ability of the radioactive microspheres to kill the tumour cells.
However, the presence of other radioactive substances that are not required for the radiation treatment of the target tissue, has then unwanted and deleterious radiation effects may occur.
While these microspheres were of an appropriate density to ensure good distribution characteristics in the liver, there were several instances in which the yttrium-90 leached from the microspheres and caused inappropriate radiation of other tissues.
Attempts to incorporate other radionuclides such as holmium into resin or polymer based materials have resulted in leaching of the radionuclide and this has resulted in severe consequences for the patients that have been treated with the product.
These glass microspheres have several disadvantages including being of a higher specific gravity than is desirable and containing other elements such as alumina and silica which are activated to undesirable radionuclides when placed in a neutron beam.

Method used

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  • Polymer based radionuclide containing particulate material
  • Polymer based radionuclide containing particulate material
  • Polymer based radionuclide containing particulate material

Examples

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example 1

[0039] Yttrium (90Y) labelled microspheres are made in the form of a sterile, pyrogen free suspension of resin beads labelled with yttrium (90Y) phosphate. The resin beads consist of sulphuric acid groups attached to a styrene divinylbenzene copolymer lattice. Yttrium oxide is irradiated to produce yttrium-90 from the nuclear reaction Y-89 (n, γ) Y-90. Yttrium-90 has a half life of 64 hours. The yttrium (90Y) oxide is then dissolved in 0.1M sulphuric acid with gentle heating and stirring to form a clear, colourless solution of yttrium (90Y) sulphate.

[0040] Symmetrical microspheres of ion exchange resin (Aminex 50W-X4 cation exchange resin; supplied by Bio-Rad Cat #1474313′) with a diameter of approximately 30 to 35 microns are added to water (Water for Injections BP) to form a slurry that is then transferred into a reaction vessel. Yttrium (90Y) sulphate solution is added to the reaction vessel and the mixture stirred at a speed sufficient to ensure homogeneity to absorb the yttriu...

example 2

[0044] The effect of phosphate concentration in the precipitation solution, and the effects of washing with phosphate buffer on the pH of a microsphere suspension are shown in the attached FIG. 1 which sets out the results of a number of experiments.

example 3

[0045] The technique of Selective Internal Radiation Therapy (SIRT) has been described above. It involves either a laparotomy to expose the hepatic arterial circulation or the insertion of a catheter into the hepatic artery via the femoral, brachial or other suitable artery. This may be followed by the infusion of Angiotensin-2 into the hepatic artery to redirect arterial blood to flow into the metastatic tumour component of the liver and away from the normal parenchyma. This is followed by embolisation of resin based yttrium-90 containing microspheres (produced in accordance with Example 1) into the arterial circulation so that they become lodged in the microcirculation of the tumour. Repeated injections of microspheres are made until the desired radiation level in the normal liver parenchyma is reached. By way of example, an amount of yttrium-90 activity that will result in an inferred radiation dose to the normal liver of approximately 80 Gy may be delivered. Because the radiatio...

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Abstract

The invention relates to a particulate material having a diameter in the range of from 5 to 200 microns comprising polymeric matrix and stably incorporated radionuclide, processes for its production and a method of radiation therapy utilising the particulate material.

Description

[0001] This application is a Continuation of application Ser. No. 10 / 173,496, filed Jun. 17, 2002, and which application(s) are incorporated herein by reference.FIELD OF THE INVENTION [0002] This invention relates to a particulate material that comprises a polymer, particularly a polymer and a radionuclide, to a method for the production thereof, and to methods for the use of this particulate material. [0003] In on particular aspect, this invention relates to microspheres which comprise a polymer and a radionuclide such as radioactive yttrium, and to the use of these microspheres in the treatment of cancer in humans and other mammals. [0004] The particulate material of this invention is designed to be administered into the arterial blood supply of an organ to be treated, whereby it becomes entrapped in the small blood vessels of target organ and irradiates it. An alternate form of administration is to inject the polymer based particulate material directly into the target organ or a ...

Claims

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Application Information

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IPC IPC(8): A61K51/00A61P35/00G21G4/08A61K51/06A61K51/12A61P1/16
CPCA61K51/06A61K51/1251A61K51/1255A61P1/16A61P35/00
Inventor GRAY, BRUCE NATHANIEL
Owner SIRTEX MEDICAL LTD
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