Surface Area

In the age of Quality by Design (QbD) and Process Analytical Techniques (PAT), specific surface area is becoming even more widely recognized for its importance in characterizing pharmaceutical materials. The specific surface area is related to particle size, particle geometry, and oftentimes particle porosity. Particle size and particle geometry influence powder flow, powder adhesion, and the pharmacokinetics of the substance. Surface area is considered to be a critical quality attribute for many APIs and has proven to be an excellent way to monitor lot-to-lot variations in materials since its value is sensitive to a number of physical deviations.

Many particle sizing instruments report particle area data, but the calculation is based on models that assume all particles to be spherical in shape and homogeneous in other properties. Furthermore, the instrument operator must enter information about these assumed homogeneous properties of the material in order for the instrument to report reliable size data upon which to base the area calculations. Surface area measurements, on the other hand, do not require such extensive knowledge of the material, but simply require that the sample is free of surface moisture or other contaminants. Removal of these contaminants is accomplished by drying the heated sample under vacuum or nitrogen purge.

MPS surface area measurement capabilities exceed those of other Contract Research Organizations (CRO). MPS’s parent company, Micromeritics Instrument Corporation, pioneered many of the analytical tools for measuring specific and absolute surface area and for almost one-half century has supplied surface area instruments to laboratories throughout the world. The laboratory technicians at MPS not only utilize the latest Micromeritics instrumentation, but are supported by the accumulated knowledge of the scientists and engineers that developed the instruments, thus assuring the highest quality data.