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.

Characterization of biotinylated liposomes sensitive to temperature and pH: New tools for anti-cancer drug delivery / A. Ferraretto, S. Sonnino, M. Soria, M. Masserini. - In: CHEMISTRY AND PHYSICS OF LIPIDS. - ISSN 0009-3084. - 82:2(1996), pp. 133-139.

Characterization of biotinylated liposomes sensitive to temperature and pH: New tools for anti-cancer drug delivery

A. Ferraretto
Primo
;
S. Sonnino
Secondo
;
1996

Abstract

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.
Settore BIO/10 - Biochimica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/189970
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