In vitro Studies of Antitumor Effect, Toxicity/Cytotoxicity and Skin Permeation/Retention of a Green Fluorescence Pyrene‐based Dye for PDT Application

Photosensitizers (PS) are compounds that can generate reactive oxygen species under irradiation of appropriate light and are widely used in photodynamic therapy (PDT). Currently, topical PDT is an effective treatment for several skin diseases, including bacterial infections, fungal mycoses and psoriasis. In addition, PDT is also used to treat nonmelanoma skin cancer and can be a potential tool for melanoma, associated with other treatments. In this work, we evaluated the antitumor photoactivity of a new pyrene‐based PS (TPPy) by using the murine melanoma cell line (B16F10). The in vitro permeation/retention tests in porcine ear skin were also performed in order to evaluate the potential application of the PS for topical use in skin cancer. Moreover, to determine the toxicity in vivo, we used the Galleria mellonella as an alternative animal model of study. The results showed that TPPy is a promising PS for application in PDT, with potential antitumor photoactivity (IC50 6.5 μmol L‐1), absence of toxicity in the G. mellonella model at higher concentration (70.0 mmol L−1) and the accumulation tendency in the epidermis plus dermis sites (165.20 ± 4.12 ng cm−2). The graphical image shows the in vitro and in vivo studies using a green fluorescent pyrene‐based photosensitizer TPPy to evaluate: (1) The toxicity, using Galleria mellonella as an alternative animal model; (2) The antitumor photoactivity of TPPy by using the murine melanoma cell line (B16F10) as a model for PDT; and (3) The permeation/retention skin tests, using porcine skin as a model, to evaluate the potential application of the TPPy for topical PDT in skin cancer.