Current Phthalocyanines Delivery Systems in Photodynamic Therapy: An Updated Review

Photodynamic therapy has emerged as an effective therapeutic alternative to treat oncological, cardiovascular, dermatological, infectious, and ophthalmic diseases. Photodynamic therapy combines the action of a photosensitizer with light in the presence of oxygen to generate reactive oxygen species, capable of reacting with cellular components, resulting in injury and, consequently, inducing cellular death. Phthalocyanines are considered good photosensitizers, although most of them are lipophilic, difficulting their administration for clinical use. A strategy to overcome the lack of solubility of phthalocyanines in aqueous media is to incorporate them into different delivery systems. The present review aimed to summarize the current status of the main drug delivery systems used for Zn and Al phthalocyanines and their effect in photodynamic therapy, reported in the last five years. Liposomes, polymeric micelles, polymeric nanoparticles, and goldnanoparticles constituted some of the most used carriers and were discussed in this review. The latest studies reported strongly suggest that the application of nanotechnologies as delivery systems allows an increase in photodynamic therapy efficacy and reduces side-effects associated with the phthalocyanine administration, which represents a hope for cancer treatments.