摘要 |
A process by means of which an increase in the particle size of a micro-ground anti-inflammatory steroid in the aerosol propellant is prevented. The increase in the particle size is prevented at the suspending stage when the solubility of the steroid into the propellant is reduced by using a low temperature and by initially mixing only a little quantity of the propellant with the steroid. If desired, the smallest and dissolved steroid particles can be removed by filtering. The particle size does not become larger even afterwards when the suspension is allowed to be stabilized for a sufficiently long time before the temperature is raised or the rest of the propellant is added. |