Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms


High production output of solid pharmaceutical formulations requires fast methods to ensure their quality. Likewise, fast analytical procedures are required in forensic sciences, for example at customs, to substantiate an initial suspicion. We here present the design and the optimization of an instrumental setup for rapid and non-invasive characterization of tablets by laser-induced fluorescence spectroscopy (with a UV-laser (λ ex = 266 nm) as excitation source) in reflection geometry. The setup was first validated with regard to repeatability, bleaching phenomena, and sensitivity. The effect on the spectra by the physical and chemical properties of the samples, e.g. their hardness, homogeneity, chemical composition, and granule grain size of the uncompressed material, using a series of tablets, manufactured in accordance with design of experiments, was investigated. Investigation of tablets with regard to homogeneity, especially, is extremely important in pharmaceutical production processes. We demonstrate that multiplicative scatter correction is an appropriate tool for data preprocessing of fluorescence spectra. Tablets with different physical and chemical characteristics can be discriminated well from their fluorescence spectra by subjecting the results to principal component analysis.

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We thank Jennifer Oppenberg (University of Münster, Germany) for her introduction to the fabrication of tablets. The help of Dr Jan Pöggeler (Forschungszentrum Jülich, Germany) is gratefully acknowledged. This project was partially funded by the Federal Ministry of Education and Research (BMBF), FZK: 13 N12012. This work was partially funded by the Excellence Initiative, a jointly funded program of the German federal and state governments, organized by the German Research Foundation (DFG).

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Correspondence to Carolin Huhn.

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Woltmann, E., Meyer, H., Weigel, D. et al. Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms. Anal Bioanal Chem 406, 6347–6362 (2014).

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  • Tablet analysis
  • Solid-state fluorescence spectroscopy
  • Grain size
  • Photobleaching
  • Scattering effects
  • Homogeneity