Microwave Assisted Pressure Filter Drying of Pharmaceutical Compounds

Abstract

A pharmaceutical product with microwave absorption characteristics similar to lactose has been successfully dried in a 0.5 m 2 microwave assisted pressure filter from acetone as solvent. The cycle time of the drying period was reduced by at least 50% when compared with downflow heated nitrogen drying in a pressure filter. The results confirm the ability to scale-up from laboratory scale. The average microwave power input was in the range 2–4 kW per m 2 of filter area. HPLC analysis of the dried active bulk drug material established that there were no breakdown products due to hot-spots or overheating. A capital utilization study indicates that an extra 50% of the main plant item cost spent on microwave assisted pressure filter drying technology will almost double the output of the unit.