Photodynamic potential of hexadecafluoro zinc phthalocyanine in nanostructured lipid carriers: physicochemical characterization, drug delivery and antimicrobial effect against Candida albicans.

This study aims to develop and characterize NCL loaded with ZnF16Pc (Pc) for application in antimicrobial photodynamic therapy. For the development of the NLC, the fusion-emulsification technique followed by sonication was applied. NLC and Pc-NLC were characterized in terms of mean diameter (Dm.n), polydispersity index (PdI), zeta potential (ZP), encapsulation efficiency (%EE), transmission electron microscopy (TEM), differential scanning (DSC), photobleaching and singlet oxygen generation in cellular systems (SOSG), and in vitro release assays performed by the beaker method, using dialysis membranes. Cell viability was performed by colony forming units (CFU/mL). The mean size of NLC and Pc-NLC was 158 nm ± 1.49 to 161.80 nm and showed PdI < 0.3 and ZP between -17.8 and -19.9, and stable during storage time (90 days). The TEM presented spherical particles, the Pc-NLC promoted the encapsulation of 75.57% ± 0.58. DSC analysis confirmed that there was no incompatibility between Pc and NLC. The analysis of the photodegradation profile proved to be photostable after encapsulation and this corroborates the data obtained by SOSG. In vitro release showed controlled and prolonged release. PDT Pc-NLC exhibited greater antifungal effect against C. albicans (3 log10 reduction) than Pc-NLC without light (1 log10 reduction). NLC can be an alternative to the application of Pc and improve the effect during PDT treatment.