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In vitro evaluation of pH-sensitive polymer/niosome complexes.
M F Francis1, G Dhara, F M Winnik
1Faculty of Pharmacy, University of Montreal, C.P. 6128 succ. Centre-Ville, Montreal, Quebec, Canada H3C 3J7.
Biomacromolecules
|November 17, 2001
Summary
pH-sensitive niosomes and liposomes were developed using a novel copolymer. While liposomes effectively delivered their cargo to the cytoplasm, niosomes showed premature leakage and cytotoxicity in serum.
Area of Science:
- Biotechnology
- Materials Science
- Drug Delivery
Background:
- Niosomes and liposomes are common drug delivery vehicles.
- pH-sensitive polymers can enhance targeted drug release.
- Controlling vesicle stability and cargo delivery is crucial for effective therapeutics.
Purpose of the Study:
- To create pH-sensitive niosomes and liposomes using a specific copolymer.
- To evaluate the stability, pH-sensitivity, and cytotoxicity of these vesicles.
- To assess their capability for cytoplasmic delivery of encapsulated substances.
Main Methods:
- Complexation of vesicles with a pH-responsive copolymer.
- Characterization of vesicle stability and pH-sensitivity in buffer and human serum.
- In vitro cytotoxicity assays and cytoplasmic delivery studies using J774 cells.
Main Results:
- Vesicles were stable at 4°C for 90 days.
- The copolymer destabilized vesicles at weakly acidic pH and 37°C.
- Niosomes, but not liposomes, were destabilized in human serum, leading to premature cargo leakage.
- Niosomes exhibited cytotoxicity above 0.075 mM, while liposomes did not.
- Only liposomes facilitated cytoplasmic delivery after cellular uptake.
Conclusions:
- The developed copolymer imparts pH-sensitivity to niosomes and liposomes.
- Liposomes demonstrated superior stability, safety, and cytoplasmic delivery efficiency compared to niosomes in this study.
- Further research is needed to optimize niosome formulations for enhanced stability and targeted delivery in biological environments.