Fariba Moghaddasi - International Campus, Ferdowsi University of Mashhad, Mashhad, Iran
Mohammad Reza Housaindokht - Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran.
Majid Darroudi - Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Mohammad Reza Bozorgmehr - Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran

Today, the use of nanoemulsions has been considered as penetration enhancers in pharmaceutical applications. In this paper, the structural properties of soybean oil -based nanoemulsion system with Tween80 as the non-ionic surfactants were investigated with molecular dynamics simulation using GROMACS. This system was simulated with the ratios obtained from experiment in 100 nanoseconds. The equilibrium of system was analyzed through the trajectory, the number of clusters, and the radius of gyration. The number of assemblies remained unchanged after 50 ns. Using the free energy landscapes, the most stable shape of assembly, 31, in system was observed asymmetric and non-spherical. The average solvent accessible surface area (SASA) value of the assembly 31 calculated to be 139.73 ± 14.00 nm2. The arrangement of the molecules in the assembly showed that the carboxyl groups (COOH) of oil and the hydroxyl groups (OH) of Tween80 were placed on the surface while the accessible water molecules and the rest of the molecule are located inside the assembly. Also the plot of radial distribution function between H (water) and O (Tween 80) show the interactions between the O hydroxyl groups (Tween 80) and H (water) is greater than O ether group, and H (water). The results of molecular dynamic simulation studies of nanoemulsion systems can be used in interpretation of practical applications of them as chemical enhancer and drug carriers.