Toxicological testing of a photoactive phthalocyanine-based antimicrobial substance

The aim of the study was toxicological testing of an innovative and efficient antimicrobial agent based on photoactive phthalocyanine (Pc) derivative. A promising Aluminium phthalocyanine (AlPc) with efficient and stable antimicrobial effects was subjected to a battery of toxicological tests to avoid local and systemic toxicity hazard. In compliance with the current European legislation restricting the use of experimental animals, the methods comprised exclusively in vitro procedures based on cellular and tissue models of human origin or mimicking human tissues. The battery of toxicological tests to identify local toxicity included skin corrosion/irritation, eye irritation, and phototoxicity. The basic systemic toxicity tests included acute toxicity, skin sensitization, genotoxicity, and endocrine disruption. The results showed that AlPc induced skin and eye irritation, exhibited borderline sensitization potential and mutagenic potential in one test strain of the Ames test, which was not confirmed in the chromosome aberration test. The AlPc was found to be phototoxic. The results from the cytotoxicity test designed for acute oral toxicity estimation were not conclusive, the acute toxicity potential has to be determined by conventional tests in vivo. Regarding endocrine disruption, no agonistic activity of the AlPc on human estrogen receptor α, nor human androgen receptor was observed. The skin penetration/absorption test revealed that the AlPc has not penetrated into the dermis and receptor fluid, confirming no risk of systemic exposure via the bloodstream.