Characterization of biotinylated liposomes sensitive to temperature and pH: new tools for anti-cancer drug delivery
✍ Scribed by Anita Ferraretto; Sandro Sonnino; Marco R. Soria; Massimo Masserini
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 510 KB
- Volume
- 82
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
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°C in fetal calf serum, liposomes composed of a mixture of dipalmitoyl phosphatidylcholine/cholesterol/GMl ganglioside/biotinoyl-dipalmitoyl phosphatidylethanolamine (100:20:6:(I.25 molar ratio) released 8% CF at pH 7.4 and 12% CF at pH 6.7. At 41°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 [~4C]glucose. The reasons for the bilayer sensitivity and the conditions for in vivo drug delivery are discussed.