Contactless conductivity detection and on-line preconcentration techniques for sensitivity enhancement in affinity interaction studies by capillary electrophoresis-frontal analysis
|Drug development comprehends broad pharmacological research which involves study of drug and plasma proteins interaction. Plasma proteins serve as reservoir for the drug molecules dependently on their binding strength. Therefore, only the free fraction of the drug performs pharmacological effect. Considering this fact, properties of affinity interaction influence setting a suitable therapeutic dose of the drug for patient. The development of new methods to obtain as much information about the interaction as possible is in demand. Capillary electrophoresis technique is attractive for its speed of analyses, high efficiency, miniaturization of analyses and possibility of automation. The established capillary electrophoresis method for the affinity interaction studies is capillary electrophoresis-frontal analysis (CE-FA). This method allows the study in almost physiological conditions without labeling or immobilization of interaction partner and provides information not only about the binding strength but also about the interaction stoichiometry. However, the technique endures a low concentration sensitivity associated with the frequently utilized universal UV-VIS detection instrument. The aim of this study is solving mentioned problem by optimizing a new more sensitive methods based on combination CE-FA method with contactless conductivity detection or on-line preconcentration techniques without an impact on the binding properties of the interaction. These methods are verified by comparing the results with data measured by conventional methods and with literature. As the most abundant plasma protein in the blood is serum albumin, this work is focused on serum albumin and salicylic acid is chosen as model drug system. Newly optimized methods have higher concentration sensitivity, binding parameters are comparable with the data measured by conventional methods and the data range from the literature.