Toward efficient enantioseparation of ibuprofen isomers using chiral BNNTs: Dispersion corrected DFT calculations and DFTB molecular dynamic simulations

Abstract

The separation of drug enantiomers in pharmaceutical industry is one of great importance since most organic compounds are chiral. In this study, the separation of ibuprofen enantiomers and the interaction between right-handed (R) and left-handed (S) isomers of ibuprofen with the outer surface as well as internal sidewall of a chiral boron nitride nanotube (BNNT(10,5)) was evaluated. The geometry optimizations and total energy calculations were performed with DFT–D3/revPBE-GGA method for various adsorption configurations. Our first-principles findings showed that interaction strength of the incorporated enantiomers into the BNNTs was higher than ones adsorbed onto the outer surface of nanotube. Also, the interaction energy difference between two enantiomers interacting with inside and outside of the BNNT was about 0.63 and 1.25 kcal/mol, respectively. This finding indicated the more ability of outer surface of BNNT in efficient enantioseparation of Ibuprofen isomers rather than inner site. Furthermore, in order to model a realistic system, tight-binding density functional molecular dynamics (DFTB–MD) simulation was performed at room temperature, and the results were consisted with the DFT–D3 findings. The nudged elastic band (NEB) method was also used to evaluate the activation energy barrier for incorporation of ibuprofen into the BNNT cavity. Our molecular simulation findings are reliable to offer beneficial information about the potential application of chiral BNNTs in enantiomer molecules adsorption and separation.