eBook: Raman Imaging in Pharmaceutical Research - 13

Component analysis of a cosmetic
cream
Many cosmetic products receive their specific properties
from microparticles, such as a smooth consistency
or an exfoliating effect. Here, the components
in a thin layer of a peeling cream were investigated.
First, a bright-field image was acquired using image
stitching to survey a large area and focus stacking to
keep all of the particles in focus (Figure 1A). Some
crystalline particles are visible as bright blue structures,
while the cream matrix appears dark gray. The
A
spatial distribution of the sample components can
be revealed by Raman imaging, in which a complete
Raman spectrum is acquired at each image pixel. A
Raman image with each pixel color-coded according
to its measured spectrum was recorded for a
small section of the bright-field image and overlaid
(Figure 1A). Three main components were identified
according to the measured spectra (Figure 1B),
namely anatase and boron nitride particles in an oil
matrix. Anatase is a crystalline form of titanium dioxide
and responsible for the peeling effect, while
boron nitride is often added to cosmetic creams as
a slip modifier.
B
C
D
Figure 1. Analysis of the particles in a cosmetic peeling cream.
A: Bright-field image with overlaid confocal Raman image. In the bright-field image, some particles are visible as bright blue structures, while the oil matrix
appears dark gray. The Raman image is color-coded according to the measured spectra shown in B, displaying the spatial distribution of the chemical components
anatase (orange), boron nitride (green) and oil (blue). B: Raman spectra of the identified components anatase (orange), boron nitride (green) and oil (blue).
C: Area size distribution of anatase (orange) and boron nitride (green) particles, quantified by their projection areas. D: Relative abundance of all sample
components. In total, 3941 particles were measured, some of them oil droplets.
13

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