HEPES buffer (HEPES (10 mM), NaCl (10 mM)), 5% D2O, and sodium trimethylsilylpropanesulfonate -DSS (1 µM). Spectra were collected at 298 K. All MAFs have an error of ± 0.05 unless otherwise stated. The PF rank highlights the most phospholipid membrane permeable (1) to the least phospholipid membrane permeable (8) agent or co-formulation. The MAF rank highlights the most membrane adherent (1) to the least membrane adherent (8) SSA or SSA co-formulation. A PF value greater than one suggests an SSA or co-formulation is permeable and an MAF value less than one suggests that an SSA or co-formulation is adhering to the phospholipid membrane. SSA' corresponds to the SSA anion with the lowest compound number in the co-formulation. SSA'' corresponds to the SSA anion with the highest compound number in the co-formulation. of the molecular components adhering to the phospholipid membrane beyond the limit of detection. Within the limits of the experiment, all of the compound appears adhered to the phospholipid membrane. e -compound adhered to the vesicle beyond the limit of detection. Within the limits of the experiment, all of the compound appears adhered to the phospholipid membrane. f -Where the MAF > 1 we hypothesise a synergistic effect between the components present. g -Independent system components could not be distinguished due to overlapping H NMR resonances.