Quantitation by MS imaging: needs and challenges in pharmaceuticals
1 ImaBiotech, MS Imaging Department, Lille, France;
Bioanalysis September 2012, Vol. 4, No. 17, Pages 2095-2098. Future-science.com
As MSI is a label-free technique, it distinguishes itself from the other imaging approaches that require labeled target molecules, such as MRI, PET or autoradiography.
Thanks to this unique feature, MSI allows the detection of thousands of molecules (targeted or untargeted) from histological tissue sections in a single experiment. It is highly specific, with 0.001 Da resolution, enabling the discrimination of all ionized molecules, such as drugs and their metabolites, at 1 ppm mass accuracy. Therefore, this approach is suitable for biodistribution studies in both large samples (rat or mouse whole-body tissue sections) [2,3] and in small organs [4,5]. Furthermore, this approach is effective for studying specific regions of the brain, eyes, lungs, liver or skin, where a high spatial resolution (20) is required and is otherwise difficult to obtain through a gold standard method such as LCƒ?”MS2 (dissection is complex). MSI, which is particularly useful in ophthalmology, neurology, dermatology, renal or hepatotoxicity, is not limited to any therapeutic area. MSI is applied in various drug discovery and development phases to study efficacy or toxicity of drugs and metabolites in screening, lead optimization and omics research (e.g., proteomics, lipidomics).
Thus, MSI provides an alternative to LC MS/MS, the standard method for plasma and tissue quantitation, by providing a greater amount of information on compound distribution in very early stages of ADMET (Table 1).
Table 1 demonstrates the speed and efficiency of the MSI technique for researchers seeking a great deal of information on drug and metabolite distribution at an early stage of drug development. It is especially powerful to study a large number of organs simultaneously without dissection or purification of the compound of interest. Unfortunately, without quantitative information, MSI uses remain limited. In this Editorial we present different methods of quantitation, which has become a key area of research in which various groups and consortia are currently developing methods