Wiktionary
microcapsule
n. A very small capsule designed to release its contents when broken (typically, after being swallowed).
Usage examples of "microcapsule".
It resembled a hardback book: microcapsules embedded in each page changed color, depending what information was loaded into it at the time.
The sleeper contained microcapsules of a sedative agent and a tiny detonator.
Perfectly smooth and free-flowing, the microcapsules rolled virtually without friction and would not acquire electrostatic charges mat might make them cling to objects on which they alighted, enabling secondary dissemination of the agent in breezes kicked up by weather, the wings of birds, or the tires of a Mack semi whipping down the interstate.