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« SPECTROSCOPY


In a recent correspondence with the authors, Dr. Sitar, currently a Professor Emeritus in the Department of Pharmacology and Therapeutics at the University of Manitoba, stated “Our initial goal was to understand the mechanism of amantadine acetylation, since initial studies ruled out the acetyltransferases NAT1 and NAT2 as contributing enzymes. With the demonstration that it was SSAT1 that specifically catalyzed acetylation of amantadine, the biological relevance to cancer and its use as a biomarker for this disease category became apparent to us.” Dr. Sitar continued saying, “Subsequently, research studies have provided data in support of this hypothesis [as previously noted in this article]. Lately, focus has been modified to identify more economical detection methods that would make the test available to a greater proportion of the world’s population.”


While traditional chemistry techniques such as LC-MS/MS work well for the detection of N-acetylamantadine in urine, when it comes to mass deployment, they suffer from 2 major drawbacks: cost and complexity. For this reason, there is a great deal of interest in finding an alternative method for the quantitation of N-acetylamantadine in biological samples, especially urine, that is low-cost, compact, and able to be operated by a laboratory technician, thus enabling large-scale clinical studies to determine the specificity and sensitivity for various cancers. The method currently showing the most promise as an alternative to the traditional methods is Raman spectroscopy. Since Raman spectroscopy probes the various vibrational and rotational modes of a molecule, it is ideal for differentiating similar molecules with different functional groups. Additionally, Raman spectroscopy is ideally suited for biological samples due to its inherent insensitivity to aqueous interference, unlike infrared spectroscopies.


When asked about the potential of Raman spectroscopy for detection of N-acetylamantadine, Dr. Sitar was recently quoted by the Royal Society of Chemistry in Chemistry World as stating, “This detection strategy is more economical than the currently used LC/MS approach, and enables development of an easy-to-use point-of- care tool that should provide more rapid turnaround to the health care provider.”30


Surface Enhanced Raman Spectroscopy


While Raman spectroscopy is known to provide a high degree of selectivity and specificity for molecular identification, it is not known as a high sensitivity method for


identifying trace amounts of a substance. This is seemingly a major issue in the detection of N-acetylamantadine in urine because it is present in concentrations on the ng/mL level. Fortunately, there exists a well- established method of signal enhancement by several orders of magnitude known as surface enhanced Raman spectroscopy


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