Method for coating powders using supercritical or subcritical fluid

摘要

Disclosed is a process for coating pulverulent solid active substances, characterized in that it comprises the following stages: a) providing a mixture comprising at least one coating agent in which is dissolved, up to saturation, a supercritical or subcritical fluid under temperature and pressure conditions which make it possible to maintain the said fluid under supercritical or subcritical conditions; b) providing separate moving particles of at least one pulverulent solid active substance; c) bringing the mixture and the separate moving particles of active substance into contact under temperature and pressure conditions which simultaneously ensure the reduction in pressure of the supercritical or subcritical fluid and its return to the gaseous state, the spraying of the coating agent and its solidification around the separate moving particles of active substance; (d) separating and recovering the coated particles.