Nanoemulsions with Chloroaluminium Phthalocyanine and Paromomycin for Combined Photodynamic and Antibiotic Therapy for Cutaneous Leishmaniasis

Abstract

Background Photodynamic therapy (PDT) using chloroaluminium phthalocyanine (ClAlPc) and paromomycin sulfate (PM) can be effective against New World Leishmania species involved in cutaneous leishmaniasis (CL). The aim of this study is to assay the skin permeation and the antileishmanial effects of a nanoemulsion (NE) containing both ClAlPc and PM in experimental CL by Leishmania (Viannia) braziliensis . Material and Methods Cremophor ELP/castor oil-based NEs were prepared by a low-energy method and characterized for their physicochemical parameters. The NEs were used to deliver both ClAlPc and PM to leishmania cells. The in vitro toxicity of NEs were tested in vitro against L. (V.) braziliensis and THP-1 cells. The in vivo toxicity was assessed in non-infected BALB/c mice. Ex-vivo permeation and retention studies using healthy mice skin were also conducted. Finally, the in vivo activity of NE-PM+ClAlPc after PDT was tested in BALB/c mice infected with parasites. Results NEs are colloidally stable with average droplet diameter of 30 nm, polydispersity index (PDI) below 0.2, and zeta potential near zero. Both promastigotes and intracellular amastigotes treated with NE-PM, NE-ClAlPc and NE-PM+ClAlPc were inhibited at >50%, >95%, >88%, respectively, after PDT with a phototoxic index (PI) >1.2. No skin ClAlPc permeation was observed. In contrast, PM skin permeation was 80-fold higher using PM-loaded NE formulation in comparison to aqueous PM solution. Topical treatment with NE formulations showed no signs of local toxicity or genotoxicity. In addition, concentrations of PM between 27.3 - 292.5 μM/25 mg of tissue were detected in different organs. In vivo , the NE-PM+ClAlPc treatment did not reduce skin lesions. Conclusion The Cremophor ELP/castor oil NE formulation increases the permeation of PM through the skin and can be used to co-deliver PM plus ClAlPc for combined PDT protocols. However, the lack of efficacy in the in vivo model evidences that the therapeutical scheme has to be improved.

Combination of the Topical Photodynamic Therapy of Chloroaluminum Phthalocyanine Liposomes with Fexinidazole Oral Self-Emulsifying System as a New Strategy for Cutaneous Leishmaniasis Treatment

“…It is important to highlight that each species of Leish mania presents specific biochemical and molecular characteristics, and their sensitivity to drugs is different [25]. Published studies reported the in vivo efficacy of treatments with FEX and ClAlPc against different species that cause leishmaniasis, such as L. donovani, L infantum, L. amazonensis, and L. braziliensis, showing promising results [5][6][7]13,15,26] However, until now, no study has been found that evaluated the effectiveness of thes treatments against L. (L.) major. On another point, combination therapy is a very prom ising alternative to improve the efficacy of the treatments against leishmaniasis.…”

“…Photodynamic therapy (PDT) is based on the photoactivation of photosensitizer molecules (PSs), which can generate cytotoxic reactive oxygen species (ROS), such as singlet oxygen ( 1 O 2 ) and free radicals when irradiated by visible light at a specific wavelength. The species can damage cellular organelles causing cell death and tissue destruction irreversibly [ 13 ]. Chloroaluminum phthalocyanine (ClAlPc) is a great PS due to its chemical stability, strong absorption spectrum in the red-light range (670–780 nm), high efficiency in generating ROS, and excellent activity against different Leishmania species after PDT [ 13 , 14 , 15 ].…”

“…The species can damage cellular organelles causing cell death and tissue destruction irreversibly [ 13 ]. Chloroaluminum phthalocyanine (ClAlPc) is a great PS due to its chemical stability, strong absorption spectrum in the red-light range (670–780 nm), high efficiency in generating ROS, and excellent activity against different Leishmania species after PDT [ 13 , 14 , 15 ]. The performance of a PS as an antileishmanial drug for topical application can be improved if an appropriate carrier is used for transdermal delivery.…”