Particle shape measurement using digital images

Fully automated digital image analysis techniques to determine particle shape and size have meant that particle shape measurement is being used increasingly in routine applications.

Today's technology requires the collection of two-dimensional representations of three-dimensional particles and Malvern systems use novel approaches to ensure the strict control of particle orientation necessary for the generation of accurate and reliable measurements.

Malvern's FPIA-2100 analyzer for wet measurements and the PharmaVision 830 system for dry applications allow linking of subtle variations in particle form to final product performance.

The FPIA-2100 is based on flow cytometry using a sheath flow mechanism to analyze wet suspensions and emulsions.

The instrument calculates diameter and circularity parameters for each particle and displays results as a scattergram, allowing the establishment of a "fingerprint" for each sample.

The sheath flow mechanism aligns particles with their major axis in the direction of flow.

This ensures that every particle is held in focus and oriented with its largest surface area facing the camera.

The PharmaVision 830 is based on automated microscopy, rapidly analyzing hundreds of thousands of particles for statistical significance.

For each particle a series of morphological parameters is calculated.

A sample preparation device uses compressed air to disperse material into a sealed chamber.

Particles then settle under gravity on to a glass plate, adopting their most mechanically stable position, with the largest surface area facing up to the camera.

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