Pharmaceutical Trends: Water Activity Measurement under USP 922 Application note

Water activity is broadly used and accepted in the food industry to control both product safety and quality. While for the pharmaceutical industry water activity has been well established to have the same efficacy, it has not yet been accepted as integral to a drug release program.

USP <1112> is an informational chapter on the application of water activity in pharma and has been in publication since 2006; however, it does not include an SOP or any validation guidance.

To remove this limitation, USP has developed USP <922> Water Activity as an official method for measuring water activity that will hopefully further facilitate the implementation of water activity as an integral part of a pharmaceutical quality program.

Both USP <922> and USP <1112> highlight the potential applications for water activity. These include stability control, microbial risk prevention, optimized formulation, reduced caking and clumping, and moisture migration control.

The resulting key benefits of these applications are: higher quality production output, greater consumer satisfaction and confidence, less product waste and recalls and, consequently, greater profits for the manufacturer.

Clearly, water activity is a powerful and often essential quality parameter for pharmaceutical products. The purpose of this application note will be to describe water activity, detail the new USP <922> water activity method, and describe in detail each of the applications for water activity in pharmaceutical products.