Characterization of anhydrous and hydrated pharmaceutical materials with THz time-domain spectroscopy
✍ Scribed by Hai-Bo Liu; Yunqing Chen; X-C Zhang
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 403 KB
- Volume
- 96
- Category
- Article
- ISSN
- 0022-3549
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✦ Synopsis
The identification of anhydrous and hydrated forms of pharmaceutical substances is of great importance in pharmaceutical science and industry. We report the use of THz time-domain spectroscopy (THz-TDS) for pseudopolymorph investigation. The anhydrous forms of pharmaceutical substances including caffeine, theophylline, D-glucose, and ampicillin exhibit different THz absorption spectra from their hydrated forms, presumably due to their different intermolecular vibrational modes mediated by hydrogen-bonding. The data from X-ray powder diffractometry (XRPD) confirm the crystallinity differences between the anhydrous and hydrated forms. The temperature-dependent THz spectra of caffeine hydrate were also recorded, and it demonstrates that THz-TDS can be used to monitor the dehydration process of drug hydrates. We conclude that THz-TDS is an advantageous technique for the pseudopolymorph identification and study, and has great potential to become a process analytical technology (PAT) in pharmaceutical production and quality control.