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Time-resolved NIR/Vis spectroscopy for analysis of solids: Pharmaceutical tablets

Johansson, J; Folestad, S; Josefson, M; Sparen, A; Abrahamsson, Christoffer LU ; Andersson-Engels, Stefan LU and Svanberg, Sune LU (2002) In Applied Spectroscopy 56(6). p.725-731
Abstract
Time-resolved spectroscopy in the visible and near-infrared (NIR) regions was used in a feasibility study for analysis of solid pharmaceuticals. The objective of the experiments was to study the interaction of light with pharmaceutical solids and to investigate the usefulness of the method as an analytical toot for spectroscopic analysis. In these experiments, a pulsed Ti:sapphire laser and white light generation in water was utilized to form a pulsed light source in the visible/NIR region. The light was focused onto the surface of tablets, and the transmitted light was detected by a time-resolving streak camera. Two types of measurements were performed. First, a spectrometer was put in front of the streak camera for spectral resolution.... (More)
Time-resolved spectroscopy in the visible and near-infrared (NIR) regions was used in a feasibility study for analysis of solid pharmaceuticals. The objective of the experiments was to study the interaction of light with pharmaceutical solids and to investigate the usefulness of the method as an analytical toot for spectroscopic analysis. In these experiments, a pulsed Ti:sapphire laser and white light generation in water was utilized to form a pulsed light source in the visible/NIR region. The light was focused onto the surface of tablets, and the transmitted light was detected by a time-resolving streak camera. Two types of measurements were performed. First, a spectrometer was put in front of the streak camera for spectral resolution. Secondly, the signal originating from different locations of the sample was collected. Time-resolved and wavelength/spatially resolved data were generated and compared for a number of different samples. The most striking result from the experiments is that the typical optical path length through a 3.5-mm-thick tablet is about 20-25 cm. This indicates very strong multiple scattering in these samples. Monte Carlo simulations and comparison with experimental data support very high scattering coefficients on the order of 500 cm(-1). Furthermore, the data evaluation shows that photons with a particular propagation time through the sample contain a higher chemical contrast than other propagation times or than steady-state information. In conclusion, time-resolved NIR spectroscopy yields more information about solid pharmaceutical samples than conventional steady-state spectroscopy. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
reflectance, near-infrared, time-resolved spectroscopy, diffuse, transmission
in
Applied Spectroscopy
volume
56
issue
6
pages
725 - 731
publisher
Society for Applied Spectroscopy
external identifiers
  • wos:000176513800008
  • scopus:0036610417
ISSN
1943-3530
DOI
10.1366/000370202760077676
language
English
LU publication?
yes
id
b432bd6e-c43c-49af-a481-8543e94cb2c3 (old id 334640)
date added to LUP
2007-10-29 13:53:33
date last changed
2017-01-01 04:19:55
@article{b432bd6e-c43c-49af-a481-8543e94cb2c3,
  abstract     = {Time-resolved spectroscopy in the visible and near-infrared (NIR) regions was used in a feasibility study for analysis of solid pharmaceuticals. The objective of the experiments was to study the interaction of light with pharmaceutical solids and to investigate the usefulness of the method as an analytical toot for spectroscopic analysis. In these experiments, a pulsed Ti:sapphire laser and white light generation in water was utilized to form a pulsed light source in the visible/NIR region. The light was focused onto the surface of tablets, and the transmitted light was detected by a time-resolving streak camera. Two types of measurements were performed. First, a spectrometer was put in front of the streak camera for spectral resolution. Secondly, the signal originating from different locations of the sample was collected. Time-resolved and wavelength/spatially resolved data were generated and compared for a number of different samples. The most striking result from the experiments is that the typical optical path length through a 3.5-mm-thick tablet is about 20-25 cm. This indicates very strong multiple scattering in these samples. Monte Carlo simulations and comparison with experimental data support very high scattering coefficients on the order of 500 cm(-1). Furthermore, the data evaluation shows that photons with a particular propagation time through the sample contain a higher chemical contrast than other propagation times or than steady-state information. In conclusion, time-resolved NIR spectroscopy yields more information about solid pharmaceutical samples than conventional steady-state spectroscopy.},
  author       = {Johansson, J and Folestad, S and Josefson, M and Sparen, A and Abrahamsson, Christoffer and Andersson-Engels, Stefan and Svanberg, Sune},
  issn         = {1943-3530},
  keyword      = {reflectance,near-infrared,time-resolved spectroscopy,diffuse,transmission},
  language     = {eng},
  number       = {6},
  pages        = {725--731},
  publisher    = {Society for Applied Spectroscopy},
  series       = {Applied Spectroscopy},
  title        = {Time-resolved NIR/Vis spectroscopy for analysis of solids: Pharmaceutical tablets},
  url          = {http://dx.doi.org/10.1366/000370202760077676},
  volume       = {56},
  year         = {2002},
}