Proton magnetic resonance study on the interaction of lidocaine derivatives with lecithin vesicles

: The interaction of lidocaine hydrochloride or lidocaine ester derivatives with lecithin vesicles was investigated by proton magnetic resonance (1H-NMR) spectroscopy. Signal broadening of drug indicated the incorporation of the drug into the vesicle membrane. Positively charged nitrogen of lidocaine hydrochloride interacted with polar part of the lecithin vesicles. On the other hand, lidocaine ester derivatives indicated interaction with lecithin vesicles not only by positive charge of nitrogen but also by electrostatic effect of ester carbonyl group. This may be related with the prolonged duration of lidocaine ester derivatives.