US: Nanoparticles shrink tumours faster

Drugs divided into nanoparticles are more effective at shrinking tumours than conventionally structured medicines, according to researchers from the Washington University School of Medicine in St Louis, Missouri.

Researchers used fumagillin-coated nanoparticles - a naturally occurring antibiotic that inhibits cell proliferation - and focused the drug directly on tumours in rabbits. They found the nanoparticles were more effective at slowing the tumour growth even though the dose was 1,000 times lower than when using traditional medicines.

"Many chemotherapeutic drugs have unwanted side effects and we've shown that our nanoparticle technology has the potential to increase drug effectiveness and decrease drug dose to alleviate harmful side effects," said lead author Dr Patrick M Winter.

The nanotechnology will be tested later this year in human trials to determine the optimal method for using them as imaging agents, which could pave the way for nanoparticles to be used as officially approved therapeutic agents.

In the trials, the nanoparticles measure only about 200 nanometres across, or 500 times smaller than the width of a human hair. They are extremely tiny beads of an inert, oily compound that can be coated with a wide variety of active substances. In addition to carrying drugs to targeted locations, the St Louis researchers say they could also be manufactured to highlight specific targets in magnetic resonance imaging, nuclear imaging, CT scanning and ultrasound imaging.

The researchers said that in their view, nanoparticle technology will be useful for monitoring cancer treatment results in both the short and long term: "It gives you a way of determining whether you should continue treatment, change the dose or even try a different treatment altogether," said Dr. Gregory Lanza, co-inventor of the technology.

The research findings come amid growing concern that accidental and undirected exposure of humans to nanoparticles could have harmful health consequences.