CHANGES IN THE ELECTRICAL PROPERTIES OF AGARGEL SUPPORTED BILAYER LIPID MEMBRANE BROUGHT ABOUT BY MIDAZOLAM

Abstract

This work describes the studies on the interaction of Midazolam (MDZ) with agar gel salt bridge supported bilayer lipid membrane (sb-BLM) using electrochemical impedance spectroscopy, cyclic voltammetry and potentiodynamic polarization methods The non-specific interaction of MDZ with sb-BLM was studied by following the dose-dependent changes in its electrical properties. MDZ was found to interact with the membrane surface at lower concentrations and impart a tightening effect which is indicated by the increase in capacitance of the membrane. At higher concentrations, MDZ molecules get partitioned into the BLM phase leading to fluidization of the membrane and in turn an increase in ionic conductance across BLM phase. Ionization of midazolam hydrochloride (MDZH+Cl−) depends on the ionic strength of the medium supporting the membranes. The ionic form of the drug interacts preferentially with the polar region of the membrane while the unionized forms are found to interact strongly with its hydrocarbon core regions. Thus, the overall electrical properties of the sb-BLM, observed with MDZ doses, are a consequence of the competitive effects brought about by these drug species on both the regions of the sb-BLMs.