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Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG)
Pei T Mah1,2, Dunja Novakovic2, Jukka Saarinen2
1School of Pharmacy, University of Otago, Dunedin, New Zealand.
Pharmaceutical Research
|October 15, 2016
Summary
Compression causes surface crystallization in amorphous griseofulvin tablets, even with excipients. Excipients, however, influence the crystallization rate within the tablet core during storage.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Solid-State Chemistry
Background:
- Amorphous solid dispersions are crucial for enhancing the solubility and bioavailability of poorly soluble drugs.
- Physical stability, particularly the tendency for crystallization, remains a significant challenge for amorphous pharmaceutical formulations.
- Understanding the factors influencing crystallization, such as mechanical stress, is vital for developing stable amorphous drugs.
Purpose of the Study:
- To investigate the impact of compression on the crystallization behavior of amorphous griseofulvin tablets.
- To evaluate the role of various excipients in mitigating compression-induced crystallization.
- To explore the utility of sum frequency generation (SFG) microscopy in analyzing solid-state transformations in amorphous tablets.
Main Methods:
- Preparation of amorphous griseofulvin tablets with and without excipients (silica, HPMCAS, MCC, PEG).
- Analysis using sum frequency generation (SFG) microscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscopy (SEM).
- Assessment of tablets upon preparation and after storage to monitor crystallization.
Main Results:
- Compression primarily induced crystallization on the surface of neat amorphous griseofulvin tablets.
- Excipients did not prevent surface crystallization but modulated the rate of crystallization in the tablet core upon compression and storage.
- SFG microscopy, alongside ATR-FTIR and SEM, provided insights into compression-induced solid-state changes.
Conclusions:
- Sum frequency generation (SFG) microscopy is a valuable tool for studying crystallization in amorphous tablets under compression and storage.
- The selection of excipients must consider their influence on the physical stability and crystallization kinetics of amorphous formulations.
- Surface crystallization is a key concern for amorphous tablets subjected to mechanical stress.
