We describe a liposome formulation characterized by sensitivity to concurrent and small temperature and pH changes. Liposome permeability was assessed by monitoring the release of entrapped carboxyfluorescein (CF), using a fluorescence dequenching technique. The thermotropic behavior of the liposomes was investigated by differential scanning calorimetry. After 2 h at 37 degrees C in fetal calf serum, liposomes composed of a mixture of dipalmitoyl phosphatidylcholine/cholesterol/GM1 ganglioside/biotinoyl-dipalmitoyl phosphatidylethanolamine (100:20:6:0.25 molar ratio) released 8% CF at pH 7.4 and 12% CF at pH 6.7. At 41 degrees C the leakage was 72% at pH 7.4 and almost complete (99%) at pH 6.7. The pH and temperature sensitivity, with maximal release when the two circumstances occurred simultaneously, was confirmed by entrapping calcein or [C-14]glucose. The reasons for the bilayer sensitivity and the conditions for in vivo drug delivery are discussed.
|Titolo:||Characterization of biotinylated liposomes sensitive to temperature and pH: New tools for anti-cancer drug delivery|
FERRARETTO, ANITA (Primo)
SONNINO, SANDRO (Secondo)
|Settore Scientifico Disciplinare:||Settore BIO/10 - Biochimica|
|Data di pubblicazione:||1996|
|Digital Object Identifier (DOI):||10.1016/0009-3084(96)02569-8|
|Appare nelle tipologie:||01 - Articolo su periodico|