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Updated: Aug 17, 2026
A Photodynamic Approach to Study Function of Intracellular Vesicle Rupture
Published on: March 17, 2023
Mechanism of photodynamic occlusion using liposomal Zn(II)-phtalocyanine
Ursula Schmidt-Erfurth1, Stephan Michels, Lars Indorf
1Universitaetsklinik für Augenheilkunde und Optometrie, Vienna, Austria. schmidt-erfurth@meduniwien.ac.at
Purpose:
To evaluate the potential of liposomal Zinc(II)-phthalocyanine (ZnPc) to selectively target subretinal vasculature.
Methods:
Photodynamic therapy (PDT) with liposomal Zinc(II)-phtalocyanine was used to induce choroidal occlusion in eyes of pigmented rabbits. Drug doses of 0.16, 0.24, 0.32, and 0.4 mg/kg body weight were administered. Photosensitization was performed at a wavelength of 671 nm and an irradiance of 100 mW/cm2 applying fluences of 5, 10, 20, and 50 J/cm2.
Results:
Using liposomal ZnPc, occlusion of choroidal vessels was achieved without damage to the overlying neurosensory retina. A tight dose correlation was found with a drug dose of 0.32 mg/kg and a light dose of 10 J/cm2 inducing a selective thrombosis of the subretinal capillary layer. Histology revealed a selective intravascular alteration of the endothelial cells.
Conclusions:
PDT using liposomal ZnPc allows occlusion of subretinal vasculature with maintenance of neuroretina and RPE. The destructive effect on choroidal vascular endothelium is intensive.
