eBook: Raman Imaging in Pharmaceutical Research - 15

always kept in focus while recording the Raman image.
Figure 3A shows a tablet with a groove. The tablet's
topography is displayed over a large area (7x7
mm²) and the simultaneously recorded Raman image
(Figure 3B) is overlaid. The groove in the tablet is
clearly visible in the topography representation, but
the Raman image remained in focus over the whole
range. Several different components were identified
and could be analyzed individually. For example,
the pink component represents paracetamol (acetaminophen).
It was isolated from the Raman image
by Pearson correlation. The Pearson image (Figure
A
3C) maps the positions at which the Raman spectrum
of the " pink component " is present. It was then
analyzed with ParticleScout, so areas in which the
component was present were recognized as a particle
and their size distribution was analyzed (Figure
3D). This procedure yielded the size distribution of
one component at the surface of the tablet without
damaging it. The remaining components may be investigated
in the same way, revealing possible differences
between the components. Of course, sections
of the tablet could be analyzed as well, in order
to investigate its interior.
B
C
D
Figure 3. Component analysis of a whole tablet's surface. Scale bar 1000 µm in all pictures.
A: Representation of the tablet's topography and chemical composition. The surface of the tablet was traced and a Raman image was simultaneously acquired
using TrueSurface. B: Raman image of the tablet's surface (7x7 mm²). Different components are color-coded. C: Pearson map for the pink component
(paracetamol). D: Size distribution of the pink component (217 particles), quantified by the circular equivalent diameter of the spots in C.
15

eBook: Raman Imaging in Pharmaceutical Research

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