Freeze-drying cycle process stages

During the studies, temperature and pressure must be controlled during all stages of the freeze drying cycle and uniform temperatures must be distributed throughout the oven used for the dry heat step. Process parameters such as the amount of moisture retained by... 

In Example 11-5, freeze crystallization of imipenem. which has lower stability in solution at room temperature, is presented. In this process, the product is rapidly frozen to an amorphous solid state to conserve its chemical purity. The temperature is then raised (still below the fieezing temperature at this stage), and the amoiphous solid converts to a crystalline solid over time. After the completion of the solid-state transition phase, the lyophilization drying cycle is initiated. 

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