Accelerated fluid bed drying using NIR monitoring and phenomenological modeling: Method assessment and formulation suitability

The theory behind a fluidized bed fast-drying method is investigated as a potential timesaving process, which can reduce overall drying time compared to single-temperature cycles. The method teaches that for formulations in which heat transfer dominates the drying mechanism, an increase in temperature during the evaporative phase of drying decreases overall process time by 50%, without changing the physical properties of the active ingredient. The method is also examined in terms of its potential for cycle shortening for a given formulation. A combined expression for the overall drying profile has been developed and committed to a macro that facilitates the identification of phenomenological trends, which identify whether or not a process will benefit by using fast drying. The relationship and macro also allows prediction of time frames associated with a given set of dryer and formulation parameters. (C) 2002 Wiley-Liss, Inc.