Tiny rocket motors can be used to send drugs into the human gut.
Radio-controlled capsules, which help direct drugs to particular sites in the digestive tract to test their effectiveness, are already common.
However, in most cases the drugs do not completely release from the capsule, reports New Scientist.
Now, Deyu Li of Vanderbilt University in Nashville, Tennessee, and colleagues have developed a more forceful drug release system.
It comprises a capsule with a drug-ejecting piston that is driven by a tiny solid-fuel rocket motor.
The researchers conducted in-vitro tests of 18 different designs to find that 20 milligrams of fuel successfully released all 16 milligrams of a drug.