Back to Search
Start Over
Pegylated tetraarylporphyrin entrapped in liposomal membranes. A possible novel drug-carrier system for photodynamic therapy.
- Source :
-
Colloids and surfaces. B, Biointerfaces [Colloids Surf B Biointerfaces] 2006 Apr 15; Vol. 49 (1), pp. 22-30. Date of Electronic Publication: 2006 Mar 06. - Publication Year :
- 2006
-
Abstract
- A system of poly(ethylene glycol) bound tetraarylporphyrin entrapped in liposomal membranes was investigated. The interactions between the 5-(4-hydroxymethylphenyl)-10,15,20-tritolylporphyrin (Po) covalently attached to the poly(ethylene glycol) chain (PEG-Po), and phosphatidylcholine liposomes in the aqueous solution were studied. The adsorption of the investigated polymer to lipid vesicles was confirmed by measurements of dynamic light scattering and zeta potential. Experimental results demonstrate that the diameter of liposomes increased and the absolute value of the zeta potential decreased after addition of PEG-Po. The binding constants (K(b)) of Po chromophores to liposome in pH range from 5.2 to 9.0 were determined using fluorescence spectroscopy. The degree of binding was found to be pH-independent and the average value was 24.6 +/- 0.9 mg ml(-1). The acid-base properties of the porphyrin chromophores and their aggregation in an aqueous solution were also studied. pK values associated with imine-N protonation of the porphyrin core were found to be 2.59 and 0.68 at the ionic strength of 0.1 M. The equilibrium constant for dimerization, K(D), was found to be 5 x 10(3) M(-1).
- Subjects :
- Adsorption
Binding Sites
Hydrogen-Ion Concentration
Light
Lipid Bilayers chemistry
Molecular Structure
Phosphatidylcholines chemistry
Photochemotherapy
Polymers chemical synthesis
Scattering, Radiation
Solubility
Solutions chemistry
Surface Properties
Water chemistry
Drug Carriers
Liposomes chemistry
Liposomes therapeutic use
Photosensitizing Agents therapeutic use
Polyethylene Glycols chemistry
Polymers chemistry
Polymers therapeutic use
Porphyrins chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0927-7765
- Volume :
- 49
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Colloids and surfaces. B, Biointerfaces
- Publication Type :
- Academic Journal
- Accession number :
- 16580183
- Full Text :
- https://doi.org/10.1016/j.colsurfb.2006.02.008