Studies on the encapsulation of diclofenac in small unilamellar liposomes of soya phosphatidylcholine

The encapsulation of acid (AD) and sodium diclofenac (SD) in small unilamellar liposomes (SUV) as well as the interactions of the drug with the bilayer was studied. SUV was prepared by sonication from multilamellar liposomes containing soya phosphatidylcholine and diclofenac at various proportions....

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Bibliographic Details
Published in:Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2004-12, Vol.39 (4), p.151-158
Main Authors: Lopes, L.B., Scarpa, M.V., Silva, G.V.J., Rodrigues, D.C., Santilli, C.V., Oliveira, A.G.
Format: Article
Language:English
Subjects:
31P NMR
Anti-Inflammatory Agents, Non-Steroidal - chemistry
Coloring Agents - chemistry
Diclofenac - chemistry
Drug Delivery Systems
Light scattering
Liposome
Liposomes - chemistry
Micelles
Mixed micelles
Models, Biological
Particle Size
Phase transformation
Phosphates - chemistry
Phosphatidylcholines - chemistry
Quaternary Ammonium Compounds - chemistry
Soybean Oil - chemistry
Surface Tension
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Summary:The encapsulation of acid (AD) and sodium diclofenac (SD) in small unilamellar liposomes (SUV) as well as the interactions of the drug with the bilayer was studied. SUV was prepared by sonication from multilamellar liposomes containing soya phosphatidylcholine and diclofenac at various proportions. The size distribution obtained from dynamic light scattering showed that the incorporation of SD decreases significantly the size of the liposomes suggesting that the drug interacts with the bilayer of the liposomes. This size decrease is related with the phase transition of liposomes to mixed micelar solution. The encapsulation of the hydrophilic dye indocyanine green in the aqueous compartment of liposomes showed that the rate of captured dye decreases with SD concentration suggesting the transition of liposomes to mixed micelles. The 31P NMR analysis indicates that SD interacts with the phosphate of phosphatidylcholine head groups. A schematic model for interaction of SD with phosphatidylcholine of the liposomes in which the diclofenac anion interacts with the ammonium group of the phospholipid and the dichlorophenyl ring occupies a more internal site of bilayer near phosphate group was proposed.
ISSN:0927-7765
1873-4367
DOI:10.1016/j.colsurfb.2004.09.004