EFFECTIVENESS OF MICROWAVE DRYING IN IMPROVING GRANULE CHARACTERISTICS IN TABLETS

In the present study, metformin hydrochloride is used as model drug and the granules were formed by using tray drying and microwave technique. The granules prepared by microwave technique and tray dryer technique are evaluated for parameters such as amount of fines, drying time, bulk density, compressibility and angle of repose. The study indicated that the granules retained their structure in comparison with the conventional drying process. The prepared granules were compressed into tablets and evaluated for hardness, friability, disintegration, and dissolution. Moreover, the microwave drying effectively improves the characteristics of granules in tablets. By adopting microwave drying technique, tablets can be prepared in less duration of time, at least 10 times less than with tray drying procedure. This can prove to be time, energy and cost efficient. The microwave technique rather advantagous because the heating or drying process is by radiation rather than conduction and convection as in conventional methods of drying and transferring heat to every molecule at same time and intensity. The only necessary criterion for microwave drying is the polarity of the solvent to be evaporated.