Analysis of Biopharmaceutical Lyophilizate Specific Surface Area by Gas Adsorption Analysis Based on Brunauer–Emmett–Teller (BET) Theory (CAT#: STEM-B-0421-CJ)

In BET, the freeze-dried sample is evacuated to remove all gases and is then cooled by using liquid nitrogen. As a next step, an inert probing gas (mostly N2) is added to the sample, which adsorbs onto the sample surface. While keeping the temperature constant, the gas pressure is increased allowing more molecules to adsorb to the sample surface (adsorption isotherm). The BET equation is now used to calculate the volume of gas needed to form a monolayer. The actual surface area can then be calculated from knowledge of the size and number of the adsorbed gas molecules.

Biopharmaceutica

1. Prepare freeze-dried samples.
2. The freeze-dried sample is vacuumed to remove all gases, then cooled with liquid nitrogen.
3. Add inert detection gas (mainly N2) to the sample and adsorb it on the surface of the sample.
4. Use BET equation to calculate the gas volume required to form monolayer. The actual surface area can be calculated from the known size and number of adsorbed gas molecules.

• Sample: Proteins, Peptides, Nucleic acids, Naturally-occurring compounds & more
• Equipment: Quantachrome AUTOSORB-1/ Brunauer-Emmett-Teller Analyzer (BET)

BET analysis is employed during lyophilization process development and formulation development. It delivers valuable insights into the structure of freeze-dried samples and helps defining optimal freeze-drying conditions.