XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
311
T6: P–19
Vibrational spectroscopy: An effective tool for active-ingredient
quantification in tablets
Sylwester Mazurek
1
, Tomasz Czaja
1
, and Roman Szostak
1
1
Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
e-mail: Sylwester.mazurek@chem.uni.wroc.pl
Medicines administered orally in the form of tablets typically contain active substances in
doses ranging from a few to a few hundred milligrams, i.e., from below 1% to higher than 90%
of tablet mass. This makes them excellent objects for quantitative analysis with the application
of infrared and Raman spectroscopy. Traditional methods commonly used in the pharmaceutical
industry for active pharmaceutical ingredients (APIs) quantification suffer from several
disadvantages. They usually require extraction of the analyzed compound, which is a laborious
and time-consuming task. In contrast, vibrational spectroscopy allows for sample analysis in its
natural state, without complicated sample-pretreatment procedures.
5
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Loratadine / FT Raman
R
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=0.9972
Rcv=0.9907
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C
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Actual C [%]
calibration
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Factor number
Fig. 1. Prediction plot, regression residuals and PRESS plot for loratadine quantification
based on Raman spectra.
The purpose of this study is to demonstrate the advantages of Raman and different infrared
reflection techniques combined with partial least squares (PLS) multivariate calibration for the
quantitative analysis of APIs in tablets. Quantification of a few important substances, including
acetylsalicylic and folic acids, fenspiride, furosemide, hydrochlorothiazide, ketoprofen,
loratadine, metformin and paracetamol, serve as examples. The proposed procedures can be
applied for fast and accurate API quantification and may replace the currently applied methods.
Keywords: quantitative analysis; tablets; Raman spectroscopy; infrared spectroscopy; multivariate calibration
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
312
4000
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Fat 8 %
Fat 6 %
Fat 4 %
Fat 2 %
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Raman Fat
R=0.9969
T6: P–20
Macronutrients quantification in yoghurts by FT-Raman spectroscopy
Tomasz Czaja
1
, Maria Baranowska
2
, Sylwester Mazurek
1
, and Roman Szostak
1
1
Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland,
e-mail: tomasz.czaja@chem.uni.wroc.pl
2
Chair of Dairy Science and Quality Management, University of Warmia and Mazury, 7
Oczapowskiego, 10-719 Olsztyn, Poland
Consumer demand for safe and healthy food enforces high-quality standards during its
production. This is connected with the use of appropriate analytical tools for the control of raw
materials, their transformation processes and evaluation of the final products. An important
group of victuals consumed by the world population are dairy products. One of the most widely
consumed dairy items is yoghurt, obtained by inoculating milk with lactic acid bacteria.
Analysis of the main components in yoghurt can be performed using classical methods. They are
time-consuming and allow quantification of only one ingredient in the system during the
analysis. Increasing food production requires reliable, rapid and low-cost analytical methods.
These criteria fulfill various vibrational spectroscopy methods.
Fig. 1. Representative Raman spectra of commercial yoghurts containing various fat levels (left) and prediction
plot for fat determination based on FT-Raman spectra (right).
FT-Raman quantitative analysis of nutritional parameters of yoghurts was performed with
the help of partial least squares (PLS) models. The relative standard errors of prediction (RSEP)
for fat, lactose and protein determination in the quantified commercial samples equalled to 3.9,
3.2 and 3.6%, respectively. PLS models based on attenuated total reflectance (ATR) spectra of
the liquid yoghurt samples and of dried yoghurt films collected with the single reflection
diamond accessory showed RSEP error values of 1.6–5.0% and 2.7–5.2%, respectively, for the
analysed components. Despite a relatively low signal-to-noise ratio in the obtained spectra,
Raman spectroscopy combined with chemometrics, constitutes a powerful tool for
macronutrients quantification in yoghurts. Errors received for ATR method were found to be
relatively higher than those for Raman spectroscopy due to inhomogeneity of the analysed
samples.
Keywords: FT-Raman; ATR; yoghurt; fat; lactose; protein; PLS; food analysis
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