Treatment time bombs

Microcapsules of drugs that self-explode within the body at set times could free patients with conditions such as cancer and HIV from the need to take numerous daily doses of medicine.

It could also benefit people in developing nations who live far from medical facilities, making vital repeat visits for treatments for diseases such as TB difficult, and could remove the need for repeat doses of vaccines to build immunity.

In research presented at EuroNanoForum 2005, researchers from Ghent University in Belgium and the Max Planck Institute of Colloids and Interfaces near Potsdam, Germany, said they had designed selfexploding microcapsules that could release drugs in bursts. These would be injected into the body.

The microcapsules are made from a biodegradable microgel surrounded by a membrane that is permeable to water but impermeable to both the microgel’s degradation products and the drugs within it. As the microgels degrade, the pressure within the capsule increases, eventually rupturing the membrane case and releasing the drug in one burst.