Sterilization, during thermal process

Consequently, the load suffers no thermal or pressure shocks because the differential pressure between the chamber and the containers can be reduced to zero or maintained at all times during the process in a direction that is suitable for the particular type of container during sterilization or, generally, during thermal treatments from 60-127°C. 

Pasteurization requires considerably less thermal input than does sterilization. Therefore, the thermal losses during pasteurization processing are quite low. However, oxidative losses can be high if care is not taken to deaerate and if high-temperature-short-time (HTST) conditions are not used (80). 

The fact that these phospholipids-stabilized emulsions are sterilized by heat may be surprising since most emulsions stabilized by almost any other surfactant is readily destabilized by heat. Indeed, the fact that the droplet size of phospholipids-stabilized emulsions actually decreases on the application of thermal stress is probably due to the behavior of the phospholipids which move from the aqueous phase to the oil phase, especially to the interfacial mesophase, during the heating process. 

These techniques include the use of inert gas atmospheres during all stages of processing, use of vacuum packaging, and post sterilization thermal treatments. These techinques are summarized in the literature (18). 

While solution crystallization is the main focus of this book, there are applications which are special cases of the CrystaUization methods described in earher chapters. For example, a process requiring sterile crystallization is a special example of an antisolvent addition and is presented in Example 11-1. In this particular example, it is necessary to produce fine particles in order to meet drug dissolution time specifications in the final single-dose vials. Furthermore, the material is thermally unstable. Therefore, special precautions have to be taken to minimize any degradation during processing. 

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