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EVALUATION AND APPLICATION OF IONIC LIQUIDS IN DISPERSIVE LIQUID-LIQUID MICROEXTRACTION (IL-DLLME) FOR ANALYSIS OF THE OMEPRAZOLE AND ITS METABOLITES IN PLASMA BY HPLC

Grant number: 15/12201-6
Support type:Regular Research Grants
Duration: November 01, 2015 - March 31, 2018
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
Principal Investigator:Cristiane Masetto de Gaitani
Grantee:Cristiane Masetto de Gaitani
Home Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Assoc. researchers:Giuliano Cesar Clososki ; Wilson Salgado Junior

Abstract

The Dispersive Liquid-Liquid Microextraction (DLLME) is a microtechnique for sample preparation that consists in compound distribution equilibrium between aqueous (donor) and organic phase (acceptor). This technique is appropriate for the extraction of moderate to high lipophilic compounds or that has its distribution coefficient (Log D) changed by pH. Two different organic solvents are used for DLLME, one with high density and miscible in aqueous phase (called extraction solvent) and another miscible in both aqueous phase and extraction solvent (called dispersive solvent). The extraction is achieved by the fast injection of the extraction/dispersive solvents mixture inside the tube with aqueous phase (sample). A cloudy solution is formed instantaneously by the dispersion of the extraction solvent through aqueous phase. After this cloud point, microdrops comprised by the extraction solvent with compound are sedimented by centrifugation and analyzed. The most commonly used dispersive solvents are methanol, ethanol, acetonitrile and acetone. Halogenated hydrocarbons as chloroform, dichloromethane, chlorobenzene, carbon tetrachloride and tetrachloroethylene are used as extraction solvents. The advantage of this technique includes easy operation, quickness, low cost, high recovery and enrichment factor for the compound. However, the use of toxic solvents (halogenated hydrocarbons) is the mean disadvantage. Thereby, the goal of this project is to evaluate the ionic liquids (IL) as DLLME extraction solvents (IL-DLLME) for the extraction of omeprazole and its metabolites from plasma samples. Three ionic liquids commercially available or obtained by synthesis will be evaluated: 1-butyl-3-methyl-imidazole hexafluorophosphate ([BMIM] [PF6]), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([C6MIM] [PF6]) e 1-octyl-3-methyl-imidazole hexafluorophosphate ([C8MIM] [PF6]). Others mayor parameters that affect the extraction technique will be also evaluated: aqueous phase pH, ionic strength and time of centrifugation. Besides, two dispersive techniques will be evaluated: IL-DLLME using ultrasson and vortex. After evaluation of all parameters and selection of the conditions that results in the best recovery and selectivity for the compounds, the method will be validated and applied for analysis of plasma samples patients' undergone bariatric surgery and treatment with omeprazole (AU)