The binding behaviour of etidocaine and TPP molecules to POPC membranes predicted by different force field parameters is illustrated in Fig. ) using the density profiles along the membrane normal and PMF curves derived from therein. For etidocaine, CHARMM36-SwissParam predicts the weakest binding affinity, followed by the CHARMM36-ParamChem and CHARMM36-Paramchem ECC. The weakest affinity for TPP ions is predicted by CHARMM36-QMcharges, followed by CHARMM36-ProteinFF and CHARMM36-QMcharges ECC.