Particle Analysis in Pharmaceutical Applications
Sensitivity - Comparing MFI to Obscuration
Indirect methods such as light obscuration perform an optical-to-electrical signal conversion and a subsequent comparison to a calibration curve to produce a result. Since the calibration curve is based on a standard (normally polystyrene beads), real particles which have different optical properties can produce erroneous results. Flow microscopy methods like MFI provide direct measurements of particles. As long as sufficient contrast exists between the particle and suspension fluid, an image with absolute dimensions will be formed.
The benefit for pharmaceutical scientists is that MFI, unlike obscuration, detects and measures particles independent of their shape, transparency or other properties. This is especially critical for analyzing proteinaceous formulations which contain semi-transparent, irregularly-shaped particles with dynamic aggregation characteristics.
This improved sensitivity has been confirmed by pharmaceutical laboratories comparing MFI to obscuration for measuring proteinaceous samples. The results below illustrate the dramatic sensitivity improvements for particles ≥10µm.
Images - Seeing is Believing!
MFI is an imaging-based technology. In addition to improved sensitivity, the additional insights provided by images provide pharamaceutical scientists with new capabilities for analyzing the source, structure, appearance, formation, dynamic properties and characteristics of particles.
