Profiling and Identification

V. G. DelVecchio, J. P. Connolly, T. G. Alefantis, A. Walz, M. A. Quan, G. Patra, J. M. Ashton, J. T. Whittington, R. D. Chafin, X. Liang, P. Grewal, A. S. Khan, and C. V. Mujer. 2006. Proteomic Profiling and Identification of Immunodominant Spore Antigens of Bacillus Anthracis, Bacillus Cereus and Bacillus Thuringiensis. Appl. Environ. Microbiol, 72(2006) 6355-6363. 

Auxiliary Techniques to Facilitate Metabolite Profiling and Identification 61... 

Yin, H., Greenberg, G. E., and Fischer, V. (2000). Application of Wallac Microbeta radioactivity counter and Wallac Scintiplate in metabolite profiling and identification studies. Application note. PerkinElmer Life Sciences, accessed at http //www.perkinelmer.com. 

A. BenAmotz, Simultaneous profiling and identification of carotenoids, retinols, and tocopherols by high performance liquid chromatography equipped with three-dimensional photodiode array detection, J. Liquid Chromatogr., 18 122 (1995). 

The urine is collected according to the preinstructed collection intervals directly from the urine collection container of the metabolism cage. The samples are weight and directly after stirring and homogenizing the urine, aliquots are taken for radioanalysis. The remainder is bottled and frozen for additional investigations planned (metabolite profile and identification and/or bioanalysis). 

Chemical biology for activity-based profiling and identification of proteases... 

Detection and identification of related substances caimot be performed by LC-MS alone. In practice, additional experiments are required using various LC gradients and/or orthogonal phase systems, alternative detection techniques like evaporative light scattering detection or optical rotation detection, and other spectroscopic techniques, like UV-DAD and NMR. Obviously, this discussion focusses primarily on the role of LC-MS in the impurity profiling and identification. Developments in LC-MS and especially mass analysers are important in strengthening the power of LC-MS in stmcture elucidation. 

To date, HPLC-NMR spectroscopy has been applied to the profiling and identification of the metabolites of a number of drugs and xenobiotics present in biofluids such as plasma, urine and in bile samples from rat and... 

The ultrahigh sensitivity of AMS enables it to follow trace amounts of radioisotope-labeled drugs in animals and humans postadministration. In addition to microdose PK studies, AMS has been utilized in many aspects of pharmaceutical research, such as absolute bioavailability determination, mass balance and metabolite profiling, and identifications of DNA and protein adducts. 

Profiling and identification of flunixin and its metabolites in the liver and kidneys of male and female feeder cattle was also carried out during the second total residue depletion study. Initially, liver tissue from cattle treated intravenously with... 

Although mass spectrometry (LC/MS and LC/MS/MS) is by far the most widely used technique for metabolite profiling and identification, it does not always provide sufficient information for unequivocal structural elucidation of metabolites. NMR spectroscopy is an excellent complementary tool for... 

There is also a demand for a universal detector that will allow quantification of drug metabolites without the need for radioisotopes or authentic reference standards. Online coupling of LC with inductively coupled plasma mass spectrometry (LC/ICPMS) offers the ability to quantify metabolites. ICPMS is an element-specific detector with almost uniform response independent of molecular structure. The response is only related to the molar content of the detected element (Axelsson et al., 2001). Unfortunately, the use of ICPMS for metabolite profiling and identification is limited to compounds containing specific elements such as P, I, F, Br, S, and selected metals. We predict that in not too distant future technologies will be available to reliably detect, identify, and quantitate major human metabolites routinely from first-in-human studies. 

In LC/MS metabolite profiling and identification analysis, other liquid chromatographic detection formats, including UV, radiodetection, and NMR, are often employed to facilitate metabolite detection, quantification, or structural characterization. These liquid chromatographic detection formats provide high analytical values that are complementary to mass spectrometry and critical to accomplishing objectives of drug metabolism studies (Zhu et al., 2009). 

TABLE 15.1 Preferred and Optional Methods for In Vitro ADME, Metabolite Profiling and Identification, and Bioanalysis Using QTRAP Instruments... 

FIGURE 15.3 (a) MRM and (b) MIM scan modes on QTRAP. MRM can be operated either MRM-only for quantification or pMRM—EPI for metabolite detection and MS/MS spectra recording. MIM is mainly used as MIM-EPI in either a targeted or screening method for metabolite profiling and identification. 

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