Abstract
A Raman spectroscopy method was developed for the quantification of the
amorphous content of lactose. Both physical mixtures and spray-dried
samples were used and the results were compared with the IMC
determinations. Sample inhomogeneities were averaged out by collecting
multiple spectra from each sample, and the total measurement time
remained below 10 min due to the high sensitivity of the CCD-Raman
spectrometer used in the measurements. The obtained calibration error
(SEC) for the physical mixtures was 1.3% (w/w) in the 0–100% amorphous
content range and was reduced to 0.2% (w/w) in the 0–10% range of more
practical interest. The crystallization heat values of the spray-dried
samples showed a linear correlation with the Raman quantifications in
the amorphous content range of 0–80%, but saturated over the 80%
concentration. This finding suggests a reference value of ca. 60 J/g for the spray-dried samples, instead of the crystallization heat of amorphous lactose (ca. 50 J/g) valid in the IMC determinations of physical mixtures.
Original language | English |
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Pages (from-to) | 907-911 |
Journal | Journal of Pharmaceutical and Biomedical Analysis |
Volume | 37 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2005 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Raman spectroscopy
- quantification
- amorphous content
- lactose