Parameters and applications
Specific surface area of particulate materials (m² per g or m² per cm³) is measured. The specific surface area determined by this method is related to the surface area accessible to an aqueous liquid. Experiences have shown that this surface area is related to the dissolution rate and bioavailability of poorly soluble active substances. The volume-surface diameter can be calculated on the basis of the specific surface area.

Prerequisites
Air permeameter, Blaine, Ph.Eur for particles below 50 µm:
1 – 2 g of dry substance. Median particle size below 50 µm. The density of the substance is required (helium pycnometry).
Drying condition should be determined.

Air permeameter for particles below 2000 µm:
Min. 70 cm³ of sample is required. The density determined by mercury porosimetry is required.