Drug – bio-affecting and body treating compositions – Radionuclide or intended radionuclide containing; adjuvant... – Coated – impregnated – or colloidal particulate
Patent
1996-09-23
1999-03-23
Dees, JoseG.
Drug, bio-affecting and body treating compositions
Radionuclide or intended radionuclide containing; adjuvant...
Coated, impregnated, or colloidal particulate
424 111, 424 129, 424 133, 424 165, A61K 5100
Patent
active
058855475
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/AU95/00027 filed Jan. 20, 1995.
FIELD OF THE INVENTION
This invention relates to a particulate material which comprises small hollow or cup-shaped ceramic particles (hereinafter referred to as "microspheres"), to a process for the production thereof, and to methods for the use of this particulate material.
In one particular aspect, this invention relates to hollow or cup-shaped ceramic microspheres which consist of or comprise a radioactive material, and to the use of these radioactive microspheres in the treatment of cancer in humans and other mammals. In this aspect, the radioactive microspheres are designed to be administered into the arterial blood supply of the organ to be treated, whereby they become entrapped in the small blood vessels of the target organ and irradiate it. An alternate form of administration is to inject the radioactive microspheres directly into the tumour to be treated.
The particulate material of the present invention therefore has utility in the treatment of various forms of cancer and tumours, but particularly in the treatment of primary and secondary cancer of the liver and the brain. It is, however, to be understood that this invention is not limited to microspheres of radioactive material, and extends to microspheres of other ceramic materials which are suitable for use in the process described herein.
BACKGROUND OF THE INVENTION
Many previous attempts have been made to locally administer radioactive materials to patients with cancer as a form of therapy. In some of these, the radioactive materials have been incorporated into small particles, seeds, wires and similar related configurations that can be directly implanted into the cancer. In other approaches, the radioactive materials have been formulated into microspheres of regular size for injection into the arterial blood supply of the target organ. When radioactive particles or microspheres are administered into the blood supply of the target organ, the technique has become known as Selective Internal Radiation Therapy (SIRT). Generally, the main form of application of SIRT has been its use to treat cancers in the liver.
There are many potential advantages of SIRT over conventional, external beam radiotherapy. Firstly, the radiation is delivered preferentially to the cancer within the target organ. Secondly, the radiation is slowly and continually delivered as the radionuclide decays. Thirdly, by manipulating the arterial blood supply with vasoactive substances (such as Angiotensin-2), it is possible to enhance the percentage of radioactive microspheres that go to the cancerous part of the organ, as opposed to the healthy normal tissues. This has the effect of preferentially increasing the radiation dose to the cancer while maintaining the radiation dose to the normal tissues at a lower level (Burton, M. A. et al.; Effect of Angiotensin-2 on blood flow in the transplanted sheep squamous cell carcinoma. Europ. J. Cancer Clin. Oncol. 1988, 24(8):1373-1376).
When microspheres or other small particles are administered into the arterial blood supply of a target organ, it is desirable to have them of a size, shape and density that results in the optimal homogeneous distribution within the target organ. 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. It has been shown that microspheres of approximately 25-50 micron in diameter have the best distribution characteristics when administered into the arterial circulation of the liver (Meade, V. et al.; Distribution of different sized microspheres in experimental hepatic tumours. Europ. J. Cancer & Clin. Oncol. 1987, 23:23-41).
If the microspheres or small particles do not contain sufficient ionising radiation, then an excessive number will be required to deliver the required radiation dose to the target organ. It has been shown that if large numbers of microspheres are a
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Dees Jose'G.
Jones Dameron
Paragon Medical Ltd.
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