Rapid screening of sildenafil and tadalafil adulterated in healthcare products by Micro-Raman spectroscopy
Article first published online: 12 JUL 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 43, Issue 12, pages 1985–1990, December 2012
How to Cite
Mao, D.-Z., Weng, X.-X. and Yang, Y.-J. (2012), Rapid screening of sildenafil and tadalafil adulterated in healthcare products by Micro-Raman spectroscopy. J. Raman Spectrosc., 43: 1985–1990. doi: 10.1002/jrs.4102
- Issue published online: 14 DEC 2012
- Article first published online: 12 JUL 2012
- Manuscript Revised: 4 APR 2012
- Manuscript Accepted: 4 APR 2012
- Manuscript Received: 13 APR 2011
- National Project of Scientific and Technical Supporting Programs. Grant Number: 11431922500
- confocal micro-Raman spectroscopy;
Sildenafil and tadalafil are inhibitors of phosphodiesterase type 5, which are frequently added into healthcare products. The objective of this study was to evaluate the possibility of using micro-Raman spectroscopy as a non-destructive technique to screen for sildenafil and tadalafil in adulterated healthcare products. Using a viewing microscope, the suspect area of healthcare products was selected, which had a discernable crystal form or shape from the surrounding zone. Optimization of instrumental parameters of the Raman spectrometer was chosen to reduce the background fluorescence, and the Raman spectra were collected. The spectra collected were compared with the standard Raman spectra of pure sildenafil and tadalafil. Samples with an identifiable Raman signature to that of sildenafil or tadalafil could be confirmed using liquid chromatography–mass spectrometry (LC/MS). Additionally, wavelet denoising combined with similarity calculation was used to establish an automated approach for discrimination of adulterated healthcare products. Correlation coefficient was chosen for similarity calculation based on the spectra collected and the standard Raman spectra of pure sildenafil and tadalafil. We compared ten samples, secured by administrative authorities in Shanghai, to analyse and demonstrate the capabilities of our proposed method. We established six samples containing sildenafil or tadalafil warranting analysis using LC/MS. Thus, the use of micro Raman spectroscopy provides a quick, convenient and non-destructive method for screening adulterated chemicals in healthcare products. Raman spectroscopy combined with similarity calculation requires little training after spectra library is developed, thus showing great promise to identify the adulterated healthcare products in the future. Copyright © 2012 John Wiley & Sons, Ltd.