1H NMR spectroscopic studies of interactions between dimyristoylphosphatidylcholine (DMPC) and europium nitrate in the presence of tetracaine.

1H NMR spectroscopic studies have been carried out for multidispersed vesicles of DMPC and DOPC in the presence of Eu(NO3)3 and anesthetics (tetracaine and lidocaine). 1H NMR signals of DMPC vesicles disappeared, while those of DOPC did not, in the coexistence of Eu(NO3)3 and the anesthetics. An addition of EDTA-Na4 to this solution regained the signals of DMPC vesicles, implying cancellation of the effect of Eu(III) ions by chelating with EDTA anions. Inter-vesicular aggregation was proposed as a molecular mechanism responsible for the signal disappearance.