Technical Note: End Of Primary Drying Methods

The process of freeze drying / lyophilization consists of three major steps, including; freezing, primary drying and secondary drying. The primary drying phase is typically the longest and most complex part of the process. Therefore, methods to automatically determine the end of primary drying can speed the process.

The purpose of primary drying is to remove all the ‘unbound' interstitial water from the product. To optimize the primary drying phase of freeze drying one of several techniques can be used.