Multimodal Dynamic NMR‐Based Elucidation of Binding and Rotational Mobility of Fluorinated Anticancer Drugs in POPC Large Unilamellar Vesicles

ABSTRACT Understanding the interactions between fluorinated anticancer drugs (FACDs) and lipid assemblies is fundamental to the development of next‐generation therapeutics with improved efficacy and pharmacological safety. To this end, atomistic‐level interactions, in terms of binding and dynamics of FACDs, such as 5‐fluoro‐2′‐deoxyuridine (5‐FdU), gemcitabine (GMTB), and capecitabine (CPTB), with POPC large unilamellar vesicles (LUVs, ∼100 nm), serving as a bilayer membrane model in aqueous solution, were investigated using a suite of dynamic nuclear magnetic resonance (NMR) techniques. The salient feature of the study includes the preferential binding of CPTB with POPC compared to 5‐FdU and GMTB by 1 H‐based 1D and 2D transient NOE ( 1 H– 1 H NOESY) experiments, and further corroborated by a combined analysis of selective and nonselective spin‐relaxation rates data. 1 H STD NMR exploited saturation transfer from POPC to interacting drugs to identify proton groups in close spatial proximity, enabling group epitope mapping. 1 H spin‐lattice relaxation times were used to discern changes in the local dynamical environment and molecular mobility of the FACDs. Furthermore, 19 F spin–spin relaxation times were used to assess chemical exchange contributions in the drug–lipid systems, with particularly pronounced effects observed for CPTB.