Characterization of 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine–N-[Methoxy(polyethylene glycerol)-2000] and Its Complex with Doxorubicin Using Nuclear Magnetic Resonance Spectroscopy and Molecular Dynamics

Polyethylene glycol (PEG) lipid nanoparticles (LNPs) spontaneously assemble in water, forming uniformly sized nanoparticles incorporating drugs with prolonged blood clearance compared to drugs alone. Previously, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine–N-[methoxy(polyethylene glycerol)-2000] (DSPE–PEG2000) and several drug adducts, including doxorubicin, were analyzed by a combination of physical and molecular dynamic (MD) studies. In this study, a complete chemical shift assignment of DSPE–PEG2000 plus or minus doxorubicin was achieved using nuclear magnetic resonance (NMR), one-dimensional selective nuclear Overhauser spectroscopy (1D-selNOESY), NOESY, correlation spectroscopy (COSY), total correlated spectroscopy (TOCSY), heteronuclear single quantum coherence (HSQC), and HSQC–TOCSY. Chemical shift perturbation, titration, relaxation enhancement, and NOESY analysis combined with MD reveal detailed structural information at the atomic level, including the location of doxorubicin in the micelle, i...