X-Ray Fluorescence Analysis of Tablets

Significance of the Topic

Analysis of elemental composition in tablets, including coating layers and active cores, is essential for quality control, formulation optimization, and regulatory compliance. Uneven distribution of elements can affect drug release, stability, and patient safety.

Objectives and Study Overview

This study demonstrates the application of X-ray fluorescence (XRF) to differentiate and quantify elements in distinct regions of pharmaceutical tablets without destructive sample preparation. Intact tablets, cross-sections, and pulverized powder were compared to assign element origins to coating or core.

Methodology and Instrumentation

Sample Preparation:

• Surface: Direct analysis of intact tablet.
• Cross-section: Tablet was sectioned to expose the interior.
• Powder: Tablet was pulverized in an agate mortar and packed into a sample holder.

Instrumentation:

• EDX-8000/7000 Energy-Dispersive XRF system
• Rh target X-ray tube, SDD detector, vacuum atmosphere
• Fundamental parameter (FP) quantification method with automatic balance setting
• Measurement conditions: 50 kV, auto current, 3 mm collimator, #2 primary filter, 100 s integration

Main Results and Discussion

Qualitative Analysis:

• Coating: Titanium was predominantly detected on the tablet surface.
• Core: Phosphorus and chlorine signals were stronger in the cross-section and powder.

Quantitative Analysis:

• Surface: Ti 2.69 wt%, Cl 0.51 wt%, P 0.031 wt%.
• Cross-section: Cl 1.68 wt%, P 0.093 wt%, Ti 0.073 wt%.
• Powder: Similar to cross-section values, confirming internal composition.

Microscopy:

• Laser microscopy revealed a coating thickness of approximately 45 μm.

Benefits and Practical Applications

• Non-destructive analysis preserves sample integrity.
• Directly identifies uneven element distribution without complex pretreatment.
• Enables rapid quality control of tablet coatings and formulation consistency.

Future Trends and Potential Applications

• Integration of micro-XRF mapping for high-resolution spatial analysis.
• Advanced software for more accurate quantification on irregular samples.
• Hyphenation with other spectroscopic methods for multi-modal profiling.
• In-line process monitoring in pharmaceutical manufacturing.

Conclusion

XRF analysis provides a straightforward, non-destructive approach to distinguish and quantify elements in tablet coatings versus cores. The method simplifies sample preparation and supports efficient quality assurance in pharmaceutical development and production.

Reference

1. Shimadzu Application News No. X255