FRIGINI Ezequiel Nazareno
congresos y reuniones científicas
Effect of Ionic strength on Ibuprofenate adsorption on a lipid bilayer of dipalmitoylphosphatidylcholine from molecular dynamics simulations
Congreso; XLIX Reunión Anual de la Sociedad Argentina de Biofísica; 2021
In this work, the free energy change in the process of transferring ibuprofenate from the bulk solution to the center of a model of the dipalmitoylphosphatidylcholine bilayer at different NaCl concentrations was calculated. Two minima were found in the free energy profile. A local minimum -located in the vicinity of the membrane- and the global free energy minimum is found in the tail region. The downward shift of free energy minima, with increasing NaCl concentration, is consistent with the results of previous works. Conversely, the upward shift of the free energy maximum with increasing ionic strength is due to the competition of sodium ions and lipids molecules to coordinate with ibuprofenate and neutralize its charge. In addition, normal molecular dynamics simulations were performed to study the effects of the ibuprofenate on lipid bilayer and in presence of a high ibuprofenate concentration. The effect of ionic strength on the properties of the lipid bilayer and on lipid-drug interactions was analyzed. The area per lipid shrinking with increasing ionic strength, volume of lipids and thickness of the bilayer is consistent with the experimental results. At a very high ibuprofenate concentration, the lipid bilayer dehydrates, and it consequently transforms into the gel phase.