title: In vivo photodynamic activity of photosensitizer-loaded nanoparticles: formulation properties, administration parameters and biological issues involved in PDT outcome.
abstract: Encapsulation of hydrophobic photosensitizers (PS) into polymeric nanoparticles (NP) has proven to be an effective alternative to organic solvents for their formulation. As NP size controls NP passage through endothelial barriers, it is a key parameter for achieving passive targeting of cancer tissues and choroidal neovascularization, secondary to age-related macular degeneration, the main applications of photodynamic therapy. In the present study, a hydrophobic PS, the meso-tetra(p-hydroxyphenyl)porphyrin, was encapsulated into biodegradable NP made of poly(D,L-lactide-co-glycolide) 50:50 via an emulsification-diffusion technique. NP batches having mean diameters of 117, 285, and 593 nm were obtained with narrow size distribution. Using the chorioallantoic membrane (CAM) of the developing chick embryo, it was demonstrated that the increase in the NP size decreased photodynamic activity in vivo. The activity of PS-loaded NP was not influenced by the volume of injection and was kept intact at least 6h after NP reconstitution. Investigation of NP circulation after IV administration by fluorescence measurements revealed that 117 nm NP reached Tmax earlier than larger NP. Confocal imaging of CAM vessels demonstrated PS uptake by endothelial cells after NP administration. It was concluded that NP size controls the photodynamic activity of the encapsulated PS.
authors.affiliation: Department of Pharmaceutics and Biopharmaceutics, University of Geneva, University of Lausanne, Switzerland.
authors.forename: Angelica
authors.initials: A
authors.lastname: Vargas
authors.forename: Michael
authors.initials: M
authors.lastname: Eid
authors.forename: Mohammed
authors.initials: M
authors.lastname: Fanchaouy
authors.forename: Robert
authors.initials: R
authors.lastname: Gurny
authors.forename: Florence
authors.initials: F
authors.lastname: Delie
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002645:Chickens; D049033:Chorioallantoic Membrane / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D008268:Macular Degeneration / Q000378:metabolism; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D010778:Photochemotherapy / Q000295:instrumentation* / Q000379:methods*; D017319:Photosensitizing Agents / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D012235:Rhodamines