Desenvolvimento e avaliação de anéis vaginais nanocompósitos contendo ftalocianina para terapia fotodinâmica contra Candida albicans

Abstract

Vulvovaginal candidiasis (VVC), mainly caused by Candida albicans, affects more than 70% of women at least once in their lifetime. The development of a vaginal ring by incorporating the photosensitizing agent zinc hexadecafluorophthalocyanine (FC) into a nanostructured lipid carrier (NLC) dispersed in ureasyl-polyether (UPEO) can combat C. albicans by antimicrobial photodynamic therapy (APT). Thus, the aim of this study was to produce and evaluate UPEO-NLC-FC rings against C. albicans. For this purpose, NLC and NLC-FC were prepared by the melt-emulsification method and the vaginal ring was produced by molds through the sol-gel method, characterized physicochemically and evaluated for activity against C. albicans. The CLN and CLN-FC were analyzed by dynamic light scattering (DLS) finding the average values of hydrodynamic distribution within the ideal range for nanoparticles for pharmacological purposes, which corroborated the values obtained by nanoparticle tracking analysis (NTA), in addition to zeta potential values near to -30 mV indicative of system stability. X-ray diffraction (XRD) suggested the presence of FC on the surface of UPEO-FC and UPEO-CLN-FC materials, due to peaks close to those observed in free FC. Microscopic analysis showed the spherical shape of CLN and CLN-FC, while UPEO-CLN-FC presented the highest average roughness among the membranes analyzed, which may promote better adhesion and control in drug release. The contact angle showed total wettability for UPEO-CLN and UPEO-CLN-FC, resulting in 0º. Fourier transform infrared spectroscopy (FTIR) spectra showed no suppression of the characteristic groups of the materials and new bands. Thermogravimetry showed an improvement in the thermal stability of CLN when dispersed in UPEO. Differential thermal analysis revealed endothermic events close to 100 °C related to solvent loss and dehydration. The in vitro drug release study showed that, for the FC released from UPEO-FC and UPEO-CLN-FC, approximately 37.8% and 39.4% were released in 24 h, respectively. In the colony counting method, FC and CLN-FC showed a 99% reduction in C. albicans growth with light application. The agar diffusion assay revealed halos of 7 and 15 mm in the groups with light, UPEO-FC and UPEO-CLN-FC, respectively, demonstrating a better activity of FC. Thus, the developed system proved capable of acting in the treatment of VVC caused by C. albicans.