Extraction and Preconcentration of the Highly Lipophilic Antioxidant 2,6-Diisobornyl-4-Methylphenol and its Metabolite from Plasma Samples for the Determination by HPLC-MS/MS

A procedure is proposed for the extraction of 2,6-diisobornyl-4-methylphenol (IBP), the molecule with potential multi-target activity, and its active metabolite 2,6-diisobornyl-4-hydroxymethylphenol (IBP-OH) from human and rat plasma samples for further determination by liquid chromatography-tandem mass spectrometry. The solubility of IBP (in mg/mL) in various organic solvents is determined. In particular, the compound is readily soluble in chloroform (346 ± 14), methyl tert-butyl ether (98.6 ± 3.8), and ethyl acetate (96.8 ± 2.0). It is shown that the use of a mixture of chloroform and isopropanol (5 : 1, v/v) as an extraction system with simultaneous protein precipitation makes it possible to extract only 66 ± 10% of IBP, while the recovery of IBP-OH is 96 ± 7%. Pre-dilution of 200 [micro]L of plasma with 300 [micro]L saline increases IBP recovery to 100 ± 4%. Drying the extracts in a vacuum concentrator (air, 45°C) with the further reconstitution of the residues in 300 [mu]L of acetonitrile facilitates the purification of biosamples and the preconcentration of analytes. The total sample preparation time does not exceed 70 min, and the duration of an analysis is 7 min, the injection volume is 2 [micro]L. The procedure has been successfully tested on actual rat plasma samples after a single oral administration of IBP (10 mg/kg in oil) in the framework of pharmacokinetic studies.
Author(s): A. P. Lakeev [sup.1] [sup.2] , E. A. Yanovskaya [sup.1] [sup.2] , V. A. Yanovsky [sup.1] , M. O. Andropov [sup.1] Author Affiliations: (1) grid.77602.34, 0000 0001 1088 3909, [...]