Microwave assisted pressure filter drying of pharmaceutical compounds

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.