Preparation and thermo-sensitivity behavior of polymer liposomes made of poly(2-ethylacrylic acid) alkylamide derivatives / 药学学报

The temperature-sensitive liposomes were constructed by poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives that were synthesized for partially modification of carboxylic groups. The thermal characteristics of liposomes were investigated by using fluorescent indicator, particle size device and fluorescence spectrophotometer system. The results showed that the liposome made of fatty amine-modified poly(2-ethylacrylate) had a marked thermal sensitive release of drugs, which is correlated with the structure of molecular of polymer and the initial ratio of composition of phospholipid. The PEAA-associated-liposomes were also shown pH-sensitive drug release under acidic condition. The poly (2-ethylacrylate) for the preparation of medium-induced thermal liposomes in vitro experiments showed a good thermal characteristics and the methods of preparing temperature-sensitive liposomes were convenient and stability.

Property of liposomal fusion induced by acid-sensitive polymer / 药学学报

The fusion between liposome-liposome, liposome-biomembarnes induced by acid-sensitive polymers has been systematically investigated. The polymer-liposomes were constructed by post-insertion method with the poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives. The liposomal fusion was studied by use of fluorescence resonance energy transfer assay, particle size, fluorescent-photometer. The results indicated that the poly (2-ethylacrylic acid)-liposomes has very strong acidic induced fusion capability. Under acidic conditions, acid-sensitive polymer liposomes fused each other, the fusion closely related to the molecular weight of acid sensitivity polymer on the surface of liposomes. The acidic fusion of polymer-liposomes was dependent upon the lipids composition, the degree of fusion was reversely related to the cholesterol contents. Acid-en ci-nsitive polymer liposomes fused with erythrocyte ghosts. The liposomal fusion induced by acid-sensitive polymer associated with the increase of membrane permeability. The good acid-sensitivity of PEAA has been further demonstrated by membrane fusion in current experiments, and the liposomes prepared with lipid anchored-poly (2-ethylacrylic acid) were developeds s a potential pH sensitive delivery system.