Pore size distribution in tablets measured with a morphological sieve.

Area of Science:

• Materials Science
• Pharmaceutical Technology
• Analytical Chemistry

Background:

• Tablet porosity and pore structure significantly impact mechanical strength and other critical properties.
• Accurate characterization of pore structure is essential for tablet formulation and quality control.

Purpose of the Study:

• To propose and validate an alternative method for characterizing tablet pore structure using SEM image analysis.
• To compare the results of SEM image analysis with traditional mercury porosimetry.

Main Methods:

• SEM micrographs of sodium chloride tablets with varying particle sizes were analyzed.
• A morphological sieve technique was employed to determine pore size distribution from SEM images.
• Artifacts from sample preparation (cracks, floating grains) were identified and their impact assessed.

Main Results:

• The image analysis method showed comparable pore size distributions to mercury porosimetry.
• Both methods indicated a shift towards larger pore sizes with increasing tablet particle size.
• Careful removal of sample preparation artifacts was crucial for accurate porosity and pore size determination.

Conclusions:

• SEM image analysis, particularly with artifact removal, provides a viable method for characterizing tablet pore structure.
• This technique offers a valuable alternative to mercury porosimetry for porosity assessment.
• The method's accuracy is supported by its agreement with experimental porosity data and mercury porosimetry results.