Washington, July 15 : Scientists at Washington University in St. Louis say that they have moved a step closer to delivering cancer-killing medicines to paediatric brain tumours.
Lead researcher on the project, Dr. Karen L. Wooley, says that her team has developed polymeric nanoparticles that can trap a drug called doxorubicin, commonly used in chemotherapy, and slowly release it over an extended time period.
She says that the release rate of the drug can be tailored, and its solubility improved by fine-tuning the polymer composition.
Writing about this research in Chemical Communications, the researchers revealed that the new approach allowed them to load more doxorubicin into the cores of the nanoparticles, compared with similar constructs.
"Typically, a polymeric micelle has three to four percent (drug) loading per nanoparticle mass. In our case, we achieved 18 to 19 percent for our nanoparticles," said Dr. Andreas Nystrom, a post-doctoral associate, who worked on the project.
The nanoparticles carrying the doxorubicin, however, were not as effective at killing cancer cells as the neat drug, admitted the researchers.
The reasons they suggested were that no targeting groups were included in the initial nanoparticles, and the entire drug payload of the nanoparticle was not released.
According to the researchers, the drug-filled nanoparticles can be made effective for treating brain tumours by decorating them with signatures that will direct them to the tumours, and away from healthy cells, a process known as tissue specific targeting.
Once attached to the tumour, the nanoparticles can release their deadly contents, killing the cancer cells and leaving the healthy cells unharmed.
"Everything depends on getting the nanoparticle to the tissue (tumor) of choice," said Nystrom.
Wooley agrees: "We have been studying these nanoparticles for some time now as a platform technology, achieving high radiolabeling efficiencies and demonstrating variable bio-distributions through a collaboration with the laboratory of Professor Mike Welch, in the Department of Radiology. Now, we are poised to take advantage of the progress made to develop the particles for diagnosis and treatment of several diseases."
She adds: "In this latest work, the nanoparticles were designed with thermally tunable core properties to serve as a host system that retains drug molecules at room temperature and then releases the cargo at physiological temperature, with a controlled drug release profile.
The results are highly promising and are allowing us to move forward to a fully functional, tumor-targeted drug delivery device. The key to making this happen is the interdisciplinary team of investigators, each of whom brings a different chemical, biological or medical expertise."