Fluorescence spectroscopy on smooth and rough solid pharmaceutical surfaces

Area of Science:

• Pharmaceutical Science
• Analytical Chemistry
• Spectroscopy

Background:

• Fluorescence spectroscopy offers sensitive, fast, non-destructive analysis for pharmaceutical process analytical technology (PAT).
• Understanding physical factors influencing fluorescence signals in solid dosage forms is crucial for accurate quantification of active pharmaceutical ingredients (API).

Purpose of the Study:

• To systematically investigate the impact of API concentration, surface roughness, and compaction pressure on fluorescence signals in low-dose solid pharmaceutical formulations.
• To advance the fundamental understanding of fluorescence behavior in solid pharmaceutical systems for PAT applications.

Main Methods:

• Utilized bench-top solid-state fluorescence spectroscopy.
• Prepared model formulations with varying tryptophan concentrations (0.10-0.50% w/w), compaction pressures, and granule milling screen sizes.
• Analyzed fluorescence response in powder blends, compacts, and granules.

Main Results:

• Observed distinct fluorescence signal variations with API concentration across different sample forms (powder, compact, granule).
• Compaction pressure systematically altered fluorescence signals on both smooth and rough surfaces.
• Granule particle size influenced fluorescence, but milling screen size did not; however, a regression model showed promising API concentration predictions.

Conclusions:

• Fluorescence spectroscopy shows potential for non-destructive API quantification in low-dose formulations.
• Systematic understanding of factors like API concentration and compaction pressure is key to optimizing fluorescence-based PAT.
• Further development of fluorescence spectroscopy is supported for addressing pharmaceutical analysis challenges.