Distribution study of atorvastatin and its metabolites in rat tissues using combined information from UHPLC/MS and MALDI-Orbitrap-MS imaging.
The combination of ultrahigh-resolution mass spectrometry imaging (UHRMSI) and ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS/MS) was used for the identification and the spatial localization of atorvastatin (AT) and its metabolites in rat tissues. Ultrahigh-resolution and high mass accuracy measurements on a matrix-assisted laser desorption/ionization (MALDI)-Orbitrap mass spectrometer allowed better detection of desired analytes in the background of matrix and endogenous compounds. Tandem mass spectra were also used to confirm the identification of detected metabolites in complex matrices. The optimization of sample preparation before imaging experiments included the tissue cryogenic sectioning (thickness 20 μm), the transfer to stainless steel or glass slide, and the selection of suitable matrix and its homogenous deposition on the tissue slice. Thirteen matrices typically used for small molecule analysis, e.g., 2,5-dihydroxybenzoic acid (DHB), 1,5-diaminonaphthalene (DAN), 9-aminoacridine (AA), etc., were investigated for the studied drug and its metabolite detection efficiency in both polarity modes. Particular matrices were scored based on the strength of extracted ion current (EIC), relative ratio of AT molecular adducts, and fragment ions. The matrix deposition on the tissue for the most suitable matrices was done by sublimation to obtain the small crystal size and to avoid local variations in the ionization efficiency. UHPLC/MS profiling of drug metabolites in adjacent tissue slices with the previously optimized extraction was performed in parallel to mass spectrometry imaging (MSI) measurements to obtain more detailed information on metabolites in addition to the spatial information from MSI. The quantitation of atorvastatin in rat liver, serum, and feces was also performed.
Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210, Pardubice, Czech Republic, Robert.Jirasko@upce.cz.
Robert
R
Jirásko
Michal
M
Holčapek
Martin
M
Kuneš
Aleš
A
Svatoš
D000818:Animals; D000069059:Atorvastatin; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005243:Feces / Q000737:chemistry*; D006538:Heptanoic Acids / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000737:chemistry*; D008297:Male; D011758:Pyrroles / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014018:Tissue Distribution / Q000502:physiology
D006538:Heptanoic Acids; D011758:Pyrroles; D000069059:Atorvastatin