Tiny bubbles of CO2 can spread out drug-laden nanoparticles (shown in green) on the surface of the lung tissue, as seen in this photomicrograph. The scale bar (red) is 31.93 micrometres across.
By Tyler Irving
Posted March 2011
Anyone who has used an inhaler knows that the best way to get drugs into your lungs is as an aerosol. With cancer drugs, however, controlled release is key; The drug must destroy tumour cells while leaving regular lung tissue alone. Now, researchers at the University of Alberta have taken a big step toward solving this problem. Their secret weapon? Bubbles.
The team, which includes oncologist Wilson Roa, pharmacist Raimar Löbenberg, and mechanical engineer Warren Finlay, have created tiny particles of poly butyl cyanoacrylate that are loaded with the chemotherapy drug doxorubicin. They use a freeze-drying technique to embed these nanoparticles into slightly larger carrier particles made of a specially formulated excipient (a pharmacologically inactive substance used as a carrier.)The excipient contains an agent that forms COwhen it contacts the lung tissue, a nano-scale version of the effervescent action in many antacid medications. The bubbles spread out the nanoparticles, distributing them evenly in the lung.
While all cells take up the drug laden particles, doxorubicin seems to have a stronger effect on cancer cells than on non-cancerous ones. Experiments in mice have shown that the bubbling particles perform much better than other methods of drug delivery, such as non-bubbling particles or injection, which don’t always reach the cancerous cells. In fact, the lung tumours are completely gone after only a few treatments with the new particles. “We’re probably going to take a little more animal toxicity data but basically it’s ready to go into human trials,” says Finlay.
Photo Credit: Warren Finlay
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