Optimization of a Raman microscopy technique to efficiently detect amorphous-amorphous phase separation in...

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Analytical Chemistry

Background:

• Amorphous-amorphous phase separation in freeze-dried protein formulations can impact drug stability and efficacy.
• Accurate detection of phase separation is crucial for quality control of biopharmaceuticals.
• Existing methods for phase separation analysis can be time-consuming.

Purpose of the Study:

• To optimize a confocal Raman microscopic technique for efficient detection of amorphous-amorphous phase separation.
• To reduce the analysis time for phase separation detection in protein formulations.
• To evaluate the performance of the optimized technique in various protein-excipient systems.

Main Methods:

• Utilized a Renishaw Raman inVia confocal microscope to collect line maps of freeze-dried protein-excipient formulations.
• Optimized parameters included collection aperture, scan time, and line map length.
• Analyzed composition by evaluating intensity of component-specific peaks at each map point.

Main Results:

• Optimized parameters (large aperture, 5 s scan time, 200 μm line map) significantly improved efficiency.
• Analysis time reduced from 2.5 hours to 0.5 hours per sample.
• Successfully detected phase separation in lysozyme-trehalose, lysozyme-isomaltose, β-lactoglobulin-dextran, and β-lactoglobulin-trehalose formulations.

Conclusions:

• The optimized confocal Raman microscopy technique is a rapid and effective tool for detecting amorphous-amorphous phase separation.
• The method successfully identified phase separation in several protein formulations where it was previously suspected.
• This technique holds promise for routine quality control of amorphous therapeutic formulations.