Importance

Loading Importance Indicators...

Abstract

Improved spray drying apparati, and methods of use thereof, have been developed. The spray drying equipment includes a primary drying chamber and a secondary drying apparatus which includes tubing having a length sufficient to increase the contact time between the drying gas and the droplets/particles to dry the particles to the extent desired, at a drying rate and temperature which would be too low to provide adequate drying without the secondary drying apparatus. The secondary drying apparatus increases the drying efficiency of the spray dryer system without increasing the drying rate, while minimizing loss in yield. Te secondary drying apparatus can include multiple secondary apparati, which are independently controlled for temperature and/or have different dimensions (cross-sectional areas and/or lengths), to allow for optimization of drying conditions. For example, in one embodiment, the temperatures of the secondary appararati are set to gradually increase, or decrease, enabling the particles to be dried at multiple temperatures and drying conditions. In another embodiment, the apparati have different dimensions to alter the velocity at which the particles are dried, to accommodate changes in particle aggregation or other properties affecting product yield. A preferred application for the spray drying process and equipment is in the production of microparticles, between about 1 and 200 .mu.m in diameter, which can be used to deliver therapeutic and diagnostic agents.

Loading the Abstract Image...

First Claim