Métodos para a determinação enantiomérica dos fármacos omeprazol, lansoprazol e pantoprazol em águas residuais e de estuário

Abstract

The use of restricted access media columns for direct injection of samples chemically complex is consolidated, but not for environmental samples. This work describes the conditions for exclusion of aquatic fulvic and humic acids. The analyses were performed comparing the areas obtained after direct injection of standards in a chromatography column of gel permeation (Tsk gel® G3000PWXL), and those obtained in in-line mode with the RAM-BSA. Through a calibration curve, using standards of sodium polystyrene sulfonates of different molecular weights, in order of the 18000 Da, the molecular weight of eluted fractions were determined. This work reports the development, validation and application of sensitive, precise and accuracy methods, by high performance liquid chromatography with direct injection of samples for the enantioselective determination of omeprazole, lansoprazole and pantoprazole drugs in environmental matrices (wastewater from the city of São Carlos, Brazil and estuarine water of the River Douro, Porto-Portugal). The methods were developed by multidimensional liquid chromatography using an octyl restricted access media bovine serum albumin column (RAM-BSA C8) in the first dimension for the exclusion of macromolecules and extraction of drugs. The enantiomeric separation of omeprazole was achieved in the second dimension with a chiral column, amylose tris (3,5-dimetylphenylcarbamate) coated onto APS-Nucleosil support, and the chiral column amylose tris (3,5- dimethoxyphenylcarbamate) coated onto APS-Nucleosil support it was used for simultaneous enantiomeric separation of lansoprazole and pantoprazole. Aliquots of 500μL of the samples were injected directly into the multidimensional chromatographic system with detection for ultraviolet-visible spectroscopy (UV-vis). The quantification limits obtained for the enantiomers of omeprazole were 15μg.L-1, and for the enantiomers of lansoprazole and pantoprazole 5.0 and 7.5μg.L-1, respectively. Lower quantification limits were obtained for the enantiomers of lansoprazole (0,60μg.L-1) and pantoprazole (0,40μg.L-1) by replacement of the UV-vis detector for the mass spectrometer in a multiple reaction monitoring (MRM) mode and increasing the injection volume for 1000μL.