Pharmaceutical attenuated total reflection

J. van der Weerd and S.G. Kazarian, Validation of macroscopic attenuated total reflection-Fourier transform infrared imaging to study dissolution of swelling pharmaceutical tablets, Appl. Spectrosc., 58, 1413-1419 (2004). 

K.L.A. Chan, S.V. Hammond and S.G. Kazarian, Apphcations of attenuated total reflection infrared spectroscopic imaging to pharmaceutical formulations. Anal. Ghent., 75, 2140-2146 (2003). 

Identifying pharmaceuticals, whether APIs or excipients used to manufacture products, and the end products themselves is among the routine tests needed to control pharmaceutical manufacturing processes. Pharmacopoeias have compiled a wide range of analytical methods for the identification of pharmaceutical APIs and usually several tests for a product are recommended. The process can be labor-intensive and time-consuming with these conventional methods. This has raised the need for alternative, faster methods also ensuring reliable identification. Of the four spectroscopic techniques reviewed in this book, IR and Raman spectroscopy are suitable for the unequivocal identification of pharmaceuticals as their spectra are compound-specific no two compounds other than pairs of enantiomers or oligomers possess the same IR spectrum. However, IR spectrometry is confronted with some practical constraints such as the need to pretreat the sample. The introduction of substantial instrumental improvements and the spread of attenuated total reflectance (ATR) and IR microscopy techniques have considerably expanded the scope of IR spectroscopy in the pharmaceutical field. Raman spectroscopy,... 

Takeuchi, Y. et al. Effects of fatty acids, fatty amines and propylene glycol on rat stratum comeum lipids and proteins in vitro measured by fourier transform inffared/attenuated total reflection (FT-IR/ATR) spectroscopy. Chemical and Pharmaceutical Bulletin 40(7) 1887-1892, 1992. 

Mak, V. H., Potts, R. O. and Guy, R. H. Percutaneous penetration enhancement in vivo measured by attenuated total reflectance infrared spectroscopy. Pharmaceutical Research 7(8) 835-841, 1990. 

Hanh BD, Neubert RHH, Wartewig S, Christ A, and Hentzsch C (2000) Drug penetration as studied by non-invasive methods Fourier transform infrared-attenuated total reflection, Fourier transform infrared, and ultraviolet photoacoustic spectroscopy. Journal of Pharmaceutical Sciences 89 1106-1113. 

Examples of nir analysis are polymer identification (126,127), pharmaceutical manufacturing (128), gasoline analysis (129,130), and on-line refinery process chemistry (131). Nir fiber optics have been used as immersion probes for monitoring pollutants in drainage waters by attenuated total internal reflectance (132). The usefulness of nir for aqueous systems has led to important biological and medical appHcations (133). 

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