Scientists from the Russian Tomsk University of Applied Sciences, along with other Russian researchers, have been able to devise a cancer treatment using radioactive actinium 225, making it 40% more effective.
The article was published in the journal ACS Applied Materials & Interfaces.
According to the authors, they have developed a special actinium packaging, which protects the body from toxic products 6-10 times better than its analogues.
Actinium 225 is a radioactive isotope first discovered as a decay product of uranium 233.
According to Tomsk University scientists, this substance is a very promising radiopharmaceutical for the treatment of various types of cancer, including the most severe.
This is due to the fact that actinium rays emit alpha particles which themselves transmit less energy than beta rays, so they strike cancer cells with greater precision without touching healthy cells.
However, the decay of actinium 225 produces toxic isotopes, francium 221 and bismuth 213, which accumulate in the liver, kidneys and spleen. According to scientists, this hinders the widespread use of encapsulated actinium in clinical treatment.
A solution to this problem was found by the university’s specialists, who proposed a unique method for packing the isotope into a protein “polymer” capsule.
They said it helps neutralize toxic isotopes and increases the therapeutic effect of actinium 225 by 40%.
Alexander Timin, one of the authors of the article, a leading researcher at Tomsk University, explained:
Actinium is a versatile analog that, in theory, can be used to treat any type of cancer if the poisoning problem is resolved.
He added, “Our method includes the use of a biodegradable polymer, whereby the capsule decomposes into harmless elements in the body after decomposing “Francium 221” and “Bismuth 213” inside it into non-hazardous isotopes.
Scientists said: The life of “Actinium 225” is 10 days, and the capsule remains valid for at least two weeks.
They added: Tests conducted on animals showed that the accumulation of the drug in the kidneys does not exceed 5% of the total volume, while using existing systems, the accumulation ranges from 30 to 35 and sometimes to 50%. At the same time, the stability of the new capsules is 70-80% higher than its analogues.
According to the specialists of Tomsk University, the physical method is still used to package “actinium”, in which it is mixed with porous polymeric nanoshells.
Scientists note that this design has proven to be extremely unreliable.
When creating new capsules, the work’s authors used chemical methods, first attaching actinium to albumin, a protein molecule, and then placing the pair in a polymer solution.
Albumin creates a strong bond with the polymer, literally surrounding it with a protective ball.
Tomsk University scientists used a commercially available “polymer” based on polypeptides and polysaccharides.