LC-APCI-MS-MS method for the tissue distribution of viaminate after oral administrations to rats

Fast and sensitive liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) method for the specific determination of viaminate in 14 kinds of rat tissues pre-treated with simple procedure was developed and validated. Biological samples were prepared by direct precipitation to skin, stomach, intestine, and liver and extracted by liquid-liquid extraction to lung, kidney, muscle, spleen, brain, fat, testes (male and female), eye, and heart. After addition of menaquinon as internal standard to tissue homogenate, the supernatant was injected into the isocratic chromatographic system using a Waters Symmetry C8 column and methanol-water-formic acid (93:7:0.1) as the eluent. The eluate was completely led into an APCI interface with selected ion monitoring mode and the analytes were quantified using triple quadrupole MS. The assays were successfully validated in the ranges 0.02-20 ng/mL for lung, 0.02-10 ng/mL for kidney, spleen, muscle, brain, fat, eye, and heart, 0.05-10 ng/mL for testicle, 0.4-100 ng/mL for liver, skin and intestine, and 1.0-200 ng/mL for stomach. The accurate and precise studies showed good reproducibility with coefficients of variation below 8.5% and the recoveries range from 90 to 109%. The analytes were chemically stable under all relevant conditions and the assays were applied in tissue distribution study. The results showed that the viaminate concentration was high in skin, low in kidney, and almost undetectable in eye and brain.