Photodynamic therapy using ultradeformable liposomes loaded with chlorine aluminum phthalocyanine against L. (V.) braziliensis experimental models

Abstract

Ultradeformable liposomes (UDLs) containing sodium cholate as edge activator could be an appropriate skin drug-delivery system for chloroaluminum phthalocyanine (ClAlPc) during photodynamic therapy (PDT) against cutaneous leishmaniasis (CL). The aim of this work was to study cell internalization, reactive oxygen species (ROS) production, and toxicity/genotoxicity and transdermal delivery of UDL-ClAlPc, and to determine whether PDT was able to induce anti-leishmanial activity in Leishmania (Viannia) braziliensis experimental models. Prepared liposomes had an average size of 118.39 nm, zeta potential of -37.83 mV, and polydispersity index of 0.15. Liposomal internalization (red fluorescence inside cells), ROS generation (green fluorescence by 2,7-dichlorodihydrofluorescein diacetate [DCFH-DA] cleavage) and non-specific DNA damage (photo-comets) were observed after PDT. Transdermal delivery of ClAlPc, measured by in vitro diffusion experiments through BALB/c skin, showed that UDL-ClAlPc was able to deliver very low quantities of ClAlPc (<1%) to deep skin layers. PDT using UDL-ClAlPc induced photodamage in mammalian cells (J774, THP-1, and NIH-3T3), promastigotes, and intracellular amastigotes without a selective response against amastigotes (selective index ≥1). Topical once-daily ClAlPc-UDL plus visible-light irradiation (20 J/cm²) twice weekly for 3 weeks was ineffective against L. (V.) braziliensis-infected BALB/c mice, whereas miltefosine 30 mg/kg/day orally for 10 days healed the lesions and scars, without parasites observed on the slides. Even though UDLs preserved ClAlPc photoactivities and were able to deliver ClAlPc to dermis, they were unable to result in healing of CL-infected mice after PDT. Experiments using different CL animal models and liposomes with increased skin permeability abilities are recommended.

Keywords: BALB/c mice; Chloroaluminum phthalocyanines; Leishmania (Viannia) braziliensis; Photodynamic therapy; Skin delivery system; Ultradeformable liposomes.