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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Detection of trace crystallinity in an amorphous system using Raman microscopy and chemometric analysis
Effendi Widjaja1, Parijat Kanaujia, Grace Lau
1Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore, Singapore. effendi_widjaja@ices.a-star.edu.sg
Summary
A new Raman microscopy method with chemometrics (BTEM/TTFA) effectively detects trace crystallinity in amorphous systems. This technique surpasses traditional powder X-ray diffraction (PXRD) for analyzing drug homogeneity.
Area of Science:
- Analytical Chemistry
- Materials Science
- Pharmaceutical Analysis
Background:
- Detecting trace crystallinity in amorphous systems is crucial for drug stability and efficacy.
- Current methods like powder X-ray diffraction (PXRD) have limitations in sensitivity for low crystallinity levels.
Purpose of the Study:
- To develop and validate a novel analytical method for detecting and characterizing trace crystallinity in amorphous systems.
- To compare the performance of the new method against powder X-ray diffraction (PXRD).
Main Methods:
- Raman microscopy mapping combined with chemometric analysis: band-target entropy minimization (BTEM) and target transformation factor analysis (TTFA).
- Application of BTEM for systems without prior information and TTFA for systems with known components.
- Utilized four different amorphous systems as model systems for validation.
Main Results:
- The developed Raman microscopy and chemometric approach demonstrated superior sensitivity in detecting trace crystallinity compared to PXRD.
- The method successfully identified and localized crystalline components within amorphous matrices.
- Spatial distribution of drug and polymer components was obtained, enabling assessment of solid dispersion homogeneity.
Conclusions:
- The combined Raman microscopy and chemometric method (BTEM/TTFA) offers a powerful and sensitive tool for analyzing trace crystallinity in amorphous systems.
- This methodology provides advantages over PXRD for characterizing amorphous solid dispersions.
- The technique is versatile and applicable to a wide range of material systems.
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