Most of the techniques developed for the freeze drying of pharmaceuticals have evolved slowly over time. A departure from the standard practices often uncovers a variety of problems, some may be anticipated, others may appear unexpected. The proposed research program will involve a series of experiments designed to evaluate the behavior of flexible pouches in the freeze drying cycle. These includes, the selection of a suitable test solution, in bag freezing studies, and a study of the parameters effecting the confined lyophilization process. The experimental data will be incorporated into a modified numerical simulation of the lyophilization within a flexible bag to project the effects of package configuration as well as to test prospective control strategies. Knowledge of the compromises inherent in defining operating conditions, control methods, and selecting a bag design will establish the necessary foundation for the overall development program.
