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Successful cutaneous delivery of the photosensitizer silicon phthalocyanine 4 for photodynamic therapy
Author(s) -
Lam M.,
Hsia A. H.,
Liu Y.,
Guo M.,
Swick A. R.,
Berlin J. C.,
McCormick T. S.,
Kenney M. E.,
Oleinick N. L.,
Cooper K. D.,
Baron E. D.
Publication year - 2011
Publication title -
clinical and experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 78
eISSN - 1365-2230
pISSN - 0307-6938
DOI - 10.1111/j.1365-2230.2010.03989.x
Subject(s) - photosensitizer , photodynamic therapy , human skin , penetration (warfare) , phthalocyanine , biomedical engineering , confocal microscopy , materials science , medicine , chemistry , nanotechnology , optics , photochemistry , genetics , operations research , engineering , biology , physics , organic chemistry
Summary Background. Photodynamic therapy (PDT) has been shown to be effective in the treatment of malignancies of a variety of organ systems, including the lungs, bladder, gastrointestinal tract and skin. Cutaneous lesions serve as ideal targets of PDT because of the accessibility of the skin to light. To achieve optimum results, the photosensitizer must be delivered effectively into the target layers of the skin within a practical timeframe, via noninvasive methods. Aim. To determine whether topical application of a second‐generation photosensitizer, silicon phthalocyanine (Pc) 4 [SiPc(OSi(CH 3 ) 2 (CH 2 ) 3 N(CH 3 ) 2 )(OH)], results in effective penetration of the skin barrier. Methods. Penetration of Pc 4 was evaluated using standard Franz‐type vertical diffusion cell experiments on surrogate materials (silicone membranes) and laser‐scanning confocal microscopy of normal skin biopsy samples from human volunteers. Results. The Franz diffusion data indicate that Pc 4 formulated in an ethanol/propylene glycol solution (70/30%, v/v) can penetrate the membrane at a flux that is appreciable and relatively invariant. Using the same formulation, Pc 4 uptake could be detected in human skin via laser‐scanning confocal microscopy. Conclusion. After topical application, Pc 4 is absorbed into the epidermis in as little as 1 h, and the absorption increased with increasing time and dose. Pc 4 can be effectively delivered into human skin via topical application. The data also suggest that the degree of penetration is time‐ and dose‐dependent.