Particle size determination by automated microscopical imaging analysis with comparison to laser diffraction

Area of Science:

• Materials Science
• Analytical Chemistry
• Pharmaceutical Sciences

Background:

• Accurate particle size distribution is crucial for pharmaceutical product performance and quality.
• Traditional methods may lack precision or speed for complex analyses.
• Microscopy offers direct visualization but requires robust quantification methods.

Purpose of the Study:

• To develop and validate a rapid, precise microscopical technique for particle size distribution analysis.
• To compare the microscopy-based method with established laser diffraction techniques.
• To assess the influence of crystalline shape on the accuracy of particle size determination.

Main Methods:

• Utilized a Carl Zeiss Axioplan microscope with a computer-controlled image analysis system.
• Performed area and volume measurements on individual particles.
• Generated distribution histograms by plotting measurements against Feret's diameter.
• Applied the technique to pharmaceutical compounds and compared results with laser diffraction data.

Main Results:

• The developed microscopical technique demonstrated good reproducibility.
• Histograms generated by microscopy showed good agreement with laser diffraction data.
• Agreement was found to be dependent on the crystalline shape of the analyzed particles.

Conclusions:

• Microscopy coupled with image analysis provides a rapid and precise method for particle size distribution determination.
• This technique is a viable alternative or complement to laser diffraction for pharmaceutical applications.
• Crystalline morphology significantly impacts the accuracy of particle size measurements, highlighting the need for shape consideration in analysis.