Synthesis of Molecularly Imprinted Polymers Based on a New Monomer "2-(4-Vinylphenyl) Quinoline-4-Carboxylic Acid" for the Selective Solid-Phase Extraction of Lamotrigine.

A new molecularly imprinted polymers (MIPs) have been prepared for the high selective extraction of lamotrigine (LTG), a widely used antiepileptic drug, in human serum. The MIPs were polymerized by bulk polymerization using our synthesized compound, 2-(4-vinylphenyl) quinolin-4-carboxylic acid, as functional monomer, which achieved better adsorption specificity than universal MIPs. Then, the molecularly imprinted solid phase extraction (MISPE) based on this material was coupled with high-performance liquid chromatography (HPLC) for the detection of LTG in human serum. The results of method validation showed that the developed method presented a good precision and accuracy, and the linearity was in the range of 1.50-40.00 mg/mL with the limit of quantitation (LOQ) at 0.20 mg/mL. The recovery ranged from 80.8% to 83.8% with RSD ranges from 5.5% to 11.1%. The validated method was successfully used to determine the concentration of LTG in human simulate serum samples.

Development and evaluation of a hydrophilic interaction liquid chromatography-MS/MS method to quantify 19 nucleobases and nucleosides in rat plasma.

As essential endogenous compounds, nucleobases and nucleosides fulfill various functions in living organisms. This study presents the development and validation of a new hydrophilic interaction liquid chromatography tandem mass spectrometry method for simultaneous quantification of 19 nucleobases and nucleosides in rat plasma. For the sample preparation, 15 kinds of protein precipitants were evaluated according to the chromatographic profile and ion response of analytes. The optimization of chromatographic separation was respectively performed using reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography mode; each separation mode included two test columns with different stationary phases. The chromatographic profile and parameters such as half-width (W1/2 ), capacity factor (K') and tailing factor (ft ) were used to evaluate the separation efficiencies. Furthermore, the adopted composition of two mobile phase systems and the concentrations of the additives in the optimum buffer system were also investigated. The developed method was fully validated and successfully applied quantitatively to determine 19 nucleobases and nucleosides in plasma from normal and diabetic nephropathy (DN) rats. Significant differences between normal and DN rats were found in plasma levels of cytosine, xanthine, thymidine, adenosine, guanosine, inosine and 8-hydroxy-2'-deoxyguanosine. This information may provide a useful reference for the discovery of potential biomarkers of DN.