Specific Surface Area Measurement Of Intact Lyophilized Cakes

As physical characterization of pharmaceuticals becomes more of a focus, analytical techniques must be able to provide data that is representative of the materials being analyzed.

Companies are implementing Quality by Design (QbD)  and Process Analytical Technologies (PAT) initiatives to ensure robustness of formulas, processes, and products. Lyophilized products have key areas where these initiatives can play roles in product and process knowledge. Measurement of the surface area of lyophilized cakes provides valuable information on process capability and product consistency. BET surface area analysis of lyophilized products currently requires manipulation of the cake prior to testing to introduce the sample into the instrument sample tubes. This type of sample preparation technique for BET surface area testing may introduce error resulting in the lack of repeatability and robustness of the analysis and possible misrepresentation of the true surface area of the sample. Also, since manipulation is destructive to the sample, no further testing can be performed.