The development of a microwave fluid-bed processor. II. Drying performance and physical characteristics of typical pharmaceutical granulations.

Four typical pharmaceutical granulations were used to measure the enhanced drying performance of a laboratory-sized microwave fluid-bed processor, the design and construction of which were presented in Part I of this work (preceding paper). Results demonstrate improvements in observed drying rates by as much as sixfold depending upon the granulation type and drying conditions. At a low inlet temperature (30 degrees C), drying was achieved with microwave power inputs of 100-125 W/liter of working capacity, whereas similar targeted moisture levels were unattainable using conventional fluid-bed drying. Microwave energy available for heating and drying was 68 to 86% of the total microwave energy inputted.