Nanoparticles of lyotropic liquid crystals loaded with a new photosensitizer (a chlorin derivative) were developed for use in
photodynamic therapy (PDT). These systems were characterized by spectrofluorimetric, dynamic light scattering, and small angle X-ray
diffraction (SAXRD) analyses. In vitro and in vivo penetration studies in animal models were performed using animal model membranes.
The systems had a particle size of 161 ± 4 nm and a polydispersity index of 0.175 ± 0.027. Furthermore, SAXRD studies demonstrated
that the preparations remained in the liquid crystalline phase type hexagonal after drug loading. The encapsulation rate was higher than
50%, and cell viability studies revealed that the nanodispersion is not harmful for L929 skin cells. In vitro and in vivo penetration studies
confirmed that the nanodispersion of hexagonal phase enabled a higher drug skin uptake compared to the control. Additionally, a fluorescence
microscopy study demonstrated a higher biodistribution of the chlorin derivative in the skin layers of hairless mice compared to the
control. Taken together, the results show the potential of this nanodispersion for the delivery of the photosensitizer into the skin, which is
a crucial condition for successful topical PDT.