Modeling the release of vinpocetine from microcapsules based on sodium alginate and chitosan by molecular dynamics

Abstract

Introduction. when developing the composition of drugs, an actual direction is the use of computer modeling methods, including the methods of molecular dynamics (MD), which significantly expanded the possibilities of chemistry, providing spatial and temporal resolution that is inaccessible in experiments.Aim. To simulation of the release of vinpocetine from sodium alginate with a shell of chitosan into solvent media by the method of MD to determine the characteristics of computer simulation, which makes it possible to obtain microcapsules with desired biopharmaceutical properties. Materials and methods. To simulate the release of vinpocetine from sodium alginate with a shell of chitosan, the MD method in the GROMOS 54a7 force field was used using the Gromacs 2019 program. Using the HyperChem 8.0.1 program, the molecules of the components of the simulated systems were constructed. The models were parameterized using the Internet service Automated Topology Builder (http://atb.uq.edu.au/).Results. Based on the results of MD modeling, the van der waals interaction energies of vinpocetine with sodium alginate (alginic acid), with chitosan (chitosan-cation) and with a solvent in terms of 1 molecule of vinpocetine were calculated. The fractions of vinpocetine molecules not bound to the polymer were also calculated. It has been established that the average values of the energy of the van der waals interaction between vinpocetine and the solvent in an acidic medium are lower than in a neutral medium. Also, in an acidic environment, in contrast to a neutral environment, a slight release of vinpocetine is observed.Conclusion. In the course of the experiment, it was found that at pH 2.0, chitosan dissolves in an aqueous medium and a slight release of vinpocetine from alginic acid into an aqueous solution of chitosan is observed (the average proportion of vinpocetine molecules not associated with sodium alginate (alginic acid) and chitosan is 2.16 ± 2.33 %), the release of vinpocetine into water at pH 6.8 is not observed.