INTERACTIONS OF INSULIN WITH DIPALMITOYLPHOSPHATIDYLCHOLINE LIPOSOMES

AIM　To study the interactions of insulin with dipalmitoylphosphatidylcholine liposomes. METHODS　The liposomes were prepared by reverse-phase evaporation vesicle method. The entrapped efficiency, size and distribution of the liposomes were determined, and the influences of insulin on entrapped efficiency, size and distribution of the liposomes were investigated. The influences of liposomes on the fluorescence emission spectra of insulin and the calcein leakage from the liposomes entrapped calcein induced by insulin were measured. RESULTS　Insulin has little influence on the size and distribution of the liposomes while the sizes of the liposomes were about 170～190 nm. The insertion of tyrosine of insulin into dipalmitoylphosphatidylcholine liposomes membrane was not deep. The insulin disturbed the liposomes membrane, induced the calcein leakage from the calcein-loaded liposomes. CONCLUSION　Amphiphilic, example insulin, may disturb the intact membrane of liposome through the interaction either hydrophobic or hydrophilic. The attention should be paid to the entrapment process of peptides into liposomes.