DEVELOPMENT OF A FORCE FIELD FOR ARTEMISININ AND MOLECULAR DYNAMICS SIMULATION OF THE DISSOLUTION OF ARTEMISININ IN DIFFERENT SOLVENTS

Artemisinin is widely employed to treat malaria. A variety of experiments have been done to research the dissolution property of artemisinin in different solvents. To have an in-depth understanding of the property, it is essential to explore the dissolution property from molecular level with molecular dynamics (MD) simulation, which needs a satisfactory force field of artemisinin. Therefore in the research a quantum chemistry based force field was developed. The quantum chemical calculation at different levels was done and Hartree-Fock (HF) level calculation gives satisfactory results. The charge distribution was then determined successfully. The van der Waals (VDW) parameters of the C unit with sp(3)-C were tuned according to the difference between the dissolution enthalpy of artemisinin in ethanol and ethyl acetate. With the developed force field, MD method was employed to successfully simulate the dissolution property of artemisinin in different solvents. The simulation results show that artemisinin molecules tends to aggregate in water, while in the aqueous solution of ethanol, the same number of artemisinin molecules tends to disperse. Furthermore, simulation results show that 8 M ethyl acetate aqueous solution has better dissolution ability than 8M ethanol aqueous. The simulation gave agreements with the experimental results.