Advancing pharmaceutical tablet analysis with laser direct infrared (LDIR) imaging

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Laser direct infrared (LDIR) spectroscopy imaging is an emerging vibrational spectroscopic technique for rapid surface analysis.
• It captures physicochemical properties like chemical identity, particle size, shape, and distribution.
• LDIR imaging is still developing, with challenges in optimizing method parameters for pharmaceutical analysis.

Purpose of the Study:

• To assess the effects of method development options in LDIR imaging for pharmaceutical analysis.
• To investigate the relationship between step size and data acquisition time in LDIR imaging.
• To compare LDIR imaging data with Raman microscopy for validation.

Main Methods:

• Analysis of in-house prepared and commercial pharmaceutical tablets using LDIR imaging.
• Collection of hyperspectral reflectance mode LDIR images.
• Comparison of LDIR images with Raman microscopy mapping data.

Main Results:

• Careful wavenumber selection is essential for effective method development in LDIR imaging.
• LDIR images showed good agreement with Raman mapping and hyperspectral data.
• LDIR imaging consistently reported smaller mean Feret diameters for active pharmaceutical ingredients (APIs) (14-40%) compared to Raman.

Conclusions:

• LDIR imaging demonstrates significant potential as a valuable spectroscopic tool for pharmaceutical applications.
• Optimization of method parameters, particularly step size and wavenumber selection, is critical for accurate analysis.
• Further validation and development are needed to address discrepancies in particle size measurements.