Studies on preconcentration and isolation process of bezafibrate onto different types of sorbents by the SPE

The performed investigations are concerned on the estimation of extraction properties of copolymer styrene-divinylbenzene (SDB-1) adsorbent and four chemically bonded silica gel materials: octadecyl (C18), octyl (C8), phenyl (C6H5), cyclohexyl (C6H11) for the solid phase extraction of bezafibrate (hypolipidaemic compound) from the model solutions and river water samples. Extraction conditions such as solvent selection, their volumes and water samples pH were found to have significant influence on extraction efficiency of the studied compound. The effect of water matrix on extraction efficiency was checked too. It was found that the best extraction efficiency of bezafibrate from water sample was obtained using bonded silica-octadecyl gel sorbents and polymer material. The presence of drug in elutes was detected by spectrophotometric (measurement of absorbance at 230 nm) and HPLC-UV methods. Under optimal conditions, recoveries of the pharmaceutical were higher than 80 %. The precision of the novel extraction procedures, calculated as coefficient variation (CV %), ranged from 0.008 to 0.018 % for the all tested sorbents.