| 摘要 |
Microporous powder charged with an active substance for the controlled release thereof, is made by spraying into a gas a homogeneous solution of a polymer, an active substance and, optionally, an inert liquid. The microporous powder may comprise a thermoplastic polymer charged with the active substance and may have a porosity of from 60 to 80%, an outer skin of the thermoplastic polymer having a thickness of from 0.1 to 1 mu m and an opening content of from 2 to 20%, the openings in the outer skin having a diameter of up to 1 mu m. The microporous powders are particularly suitable for the controlled release of active substances over a prolonged period. |
