Diblock Copolymer Micelles Deliver Hydrophobic Protoporphyrin IX for Photodynamic Therapy

Polymeric micelles are emerging as an effective drug delivery system for hydrophobic photosensitizers in photodynamic therapy (PDT). The objective of this study was to investigate the formulation of hydrophobic protoporphyrin IX (PpIX) with MePEG5000‐b‐PCL4100 [methoxy poly (ethylene glycol)‐b‐poly...

Full description

Saved in:
Bibliographic Details
Published in:Photochemistry and photobiology 2007-11, Vol.83 (6), p.1505-1512
Main Authors: Li, Buhong, Moriyama, Eduardo H., Li, Fugang, Jarvi, Mark T., Allen, Christine, Wilson, Brian C.
Format: Article
Language:English
Subjects:
Cell Line
Cell Survival - drug effects
Cells
Chemicals
Clinical outcomes
Copolymers
Hydrophobic and Hydrophilic Interactions
Magnetic Resonance Spectroscopy
Micelles
Microscopy, Electron, Transmission
Photochemotherapy
Photodynamic therapy
Polyesters - chemistry
Polyethylene Glycols - chemistry
Proteins
Protoporphyrins - chemistry
Protoporphyrins - pharmacology
Purchasing
Software packages
Spectrophotometry
Tissues
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Polymeric micelles are emerging as an effective drug delivery system for hydrophobic photosensitizers in photodynamic therapy (PDT). The objective of this study was to investigate the formulation of hydrophobic protoporphyrin IX (PpIX) with MePEG5000‐b‐PCL4100 [methoxy poly (ethylene glycol)‐b‐poly (caprolactone)] diblock copolymers and to compare their PDT response to that of free PpIX. The photophysical and photochemical properties of the polymeric PpIX micelles were studied by measuring absorbance and fluorescence spectra, PpIX‐loading efficiency and stability, the micelle particle size and morphology, as well as singlet oxygen luminescence and lifetime. The spherical micelles have a high PpIX‐loading efficiency of 82.4% and a narrow size distribution with a mean diameter of 52.2 ± 6.4 nm. The cellular uptake of PpIX in RIF‐1 cells using PpIX micelles was approximately two‐fold higher than that for free PpIX. Free PpIX and PpIX formulated in micelles exhibited similar subcellular localization in or around the cellular plasma membrane, as demonstrated using fluorescence microscopy. In vitro PDT results showed that the PpIX micelles have markedly increased photocytotoxicity over that with free PpIX, by nearly an order of magnitude at the highest light dose used. The micelles alone had no evident phototoxicity or dark toxicity. These findings suggest that MePEG5000‐b‐PCL4100 diblock copolymer micelles have great potential as a drug delivery system for hydrophobic photodynamic sensitizers.
ISSN:0031-8655
1751-1097
DOI:10.1111/j.1751-1097.2007.00194.x