Abstract
The interaction of chlorpromazine hydrochloride with lecithin vesicles was investigated through proton magnetic resonance measurements. Sharp N (CH3)2 signal of the chlorpromazine hydrochloride in D2O was markedly broadened when the drug was added to a lecithin vesicle-D2O solution, whereas the broadening was not observed in a dextran-D2O solution of which viscosity was higher than the vesicle solution. Addition of Eu3+ to the vesicle solution induced an upfield shift of outward facing choline methyl signal, but the subsequent addition of the chlorpromazine hydrochloride reversed the induced shift. The vesicles prepared in the presence of Mn2+ did not show the PMR signal of choline methyl due to the presence of Mn2+ both inside and outside of the vesicles, but when the drug was added to the solution, choline methyl signal appeared again. The results confirmed that the chlorpromazine interacted with polar part of the lecithin vesicles displacing the trivalent ion Eu3+ and the divalent ion Mn2+ from the vesicle surfaces.
