Unfamiliarity with Freeze-Drying Parameters

A freeze-drying process was developed for a client for a preparation that contained 2 mg of a bioactive (cytotoxic) material and 51 mg of excipient, made up to 10 ml with water process parameters are shown in Column 2 of Table 3. Starting with a measurement of 7, and the 

Even later, the same client returned with a further complaint . A minor change in the formulation had been performed by a small increase in the content of bioactive material to 5 mg. Freeze-drying had failed to provide a successful product, despite the employment of the recommended cycle. Since a change had now occurred in the composition of the solution, a further Tg measurement had to be performed, with the result of —36°C, thus requiring a complete recalculation of the drying cycle, as shown in Column 4 of Table 3. Thus, a combination of a low Tg with the suboptimal fill depth required a drying cycle that may well have been uneconomical. Possibly, a reformulation might have led to a more efficient process. 

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