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

Cutaneous leishmaniasis (CL) is a neglected tropical disease. The treatment is restricted to drugs, such as meglumine antimoniate and amphotericin B, that exhibit toxic effects, high cost, long-term treatment, and limited efficacy. The development of new alternative therapies, including the identification of effective drugs for the topical and oral treatment of CL, is of great interest. In this sense, a combination of topical photodynamic therapy (PDT) with chloroaluminum phthalocyanine liposomes (Lip-ClAlPc) and the oral administration of a self-emulsifying drug delivery system containing fexinidazole (SEDDS-FEX) emerges as a new strategy. The aim of the present study was to prepare, characterize, and evaluate the efficacy of combined therapy with Lip-ClAlPc and SEDDS-FEX in the experimental treatment of Leishmania (Leishmania) major. Lip-ClAlPc and SEDDS-FEX were prepared, and the antileishmanial efficacy study was conducted with the following groups: 1. Lip-ClAlPc (0.05 mL); 2. SEDDS-FEX (50 mg/kg/day); 3. Lip-ClAlPc (0.05 mL)+SEDDS-FEX (50 mg/kg/day) combination; 4. FEX suspension (50 mg/kg/day); and 5. control (untreated). BALB/c mice received 10 sessions of topical Lip-ClAlPc on alternate days and 20 consecutive days of SEDDS-FEX or FEX oral suspension. Therapeutical efficacy was evaluated via the parasite burden (limiting-dilution assay), lesion size (mm), healing of the lesion, and histological analyses. Lip-ClAlPc and SEDDS-FEX presented physicochemical characteristics that are compatible with the administration routes used in the treatments. Lip-ClAlPc+SEDDS-FEX led to a significant reduction in the parasitic burden in the lesion and spleen when compared to the control group (p < 0.05) and the complete healing of the lesion in 43% of animals. The Lip-ClAlPc+SEDDS-FEX combination may be promising for the treatment of CL caused by L. major.

A new oral self-emulsifying drug delivery system improves the antileishmania efficacy of fexinidazole in vivo.

The aim of this study was to develop, characterize and evaluate the in vivo oral efficacy of self-emulsifying drug delivery systems (SEDDS) containing fexinidazole (FEX) in the experimental treatment of visceral leishmaniasis (VL). The developed FEX-SEDDS formulation presented as a clear, yellowish liquid, with absence of precipitate. The droplet size, polydispersion index and zeta potential after dilution in water (1:200) was of 91 ± 3 nm, 0.242 ± 0.005 and -16.7 ± 0.2, respectively. In the simulated gastric and intestinal media, the FEX-SEDDS had a size of 97 ± 1 and 106 ± 9 nm, respectively. The FEX retention in droplet after SEDDS dilution in simulated gastrointestinal media was almost 100 %. Antileishmanial efficacy studies showed that FEX-SEDDS was the only treatment able to significantly (p < 0.05) reduce the parasite burden in the liver and spleen of animals experimentally infected with Leishmania infantum. Our intestinal permeability data suggest that FEX-SEDDS showed no evidence of injury to the intestinal mucosa. These findings suggest that FEX-SEDDS can be a promising oral alternative for the treatment of VL caused by L. infantum.

Topical photodynamic therapy with chloroaluminum phthalocyanine liposomes is as effective as systemic pentavalent antimony in the treatment of experimental cutaneous leishmaniasis.

BACKGROUND: In the Americas, one of the main causative species of cutaneous leishmaniasis is Leishmania (Leishmania) amazonensis. The systemic antimonials remain the most largely used option for disease control. However, this drug has significant toxicity. The development of new alternative therapies, including the identification of effective drugs for topical treatment of cutaneous leishmaniasis, is of utmost interest. In this sense, photodynamic therapy emerges as a new strategy. The aim of this study was to develop the chloroaluminum phthalocyanine-loaded liposome, characterize it, and evaluate its stability and efficacy in the topical treatment of cutaneous leishmaniasis caused by L. (L.) amazonensis. METHODS: Liposomes composed of egg phosphatidylcholine were prepared by Bangham's method. Storage stability of phthalocyanine-loaded liposomes was evaluated at 30 and 60 days after preparation. For the in vivo evaluation, the animals were infected with L. (L.) amazonensis and divided into groups: chloroaluminium phthalocyanine-loaded liposome, blank liposome, meglumine antimoniate (200 mgSb+5/Kg/day), and control. The lesion size was determined weekly after the beginning of the treatment. Upon completion, parasites were recovered from the skin lesion and spleen and evaluated by limiting dilution assay. RESULTS: Chloroaluminum phthalocyanine-loaded liposomes were stable and showed adequate characteristics for topical administration. The topical chloroaluminum phthalocyanine-loaded liposome was as effective as systemic pentavalent antimony in reducing the parasitic load in the lesion and spleen in infected animals. CONCLUSIONS: The present study showed that photodynamic therapy with chloroaluminum phthalocyanine-loaded liposomes is a promising strategy for the treatment of American cutaneous leishmaniasis caused by L. (L.) amazonensis.

Plasma antimony determination during cutaneous leishmaniasis treatment with intralesional infiltration of meglumine antimoniate.

OBJECTIVES: To evaluate the antimony (Sb) in plasma of patients who underwent a standardised meglumine antimoniate (MA) intralesional infiltration protocol for cutaneous leishmaniasis treatment. METHODS: The level of Sb in plasma was determined by atomic absorption spectroscopy, before and 1, 2, 4 and 6 hours after the first intralesional infiltration of MA to determine the parameters peak concentrations (C1 h ), area under curve of drug concentration in plasma from zero to 6 h (AUC0-6 h ) and elimination half-life (t½) of Sb. Blood samples were also collected weekly during the treatment period, always before infiltration. RESULTS: Fourteen patients underwent MA intralesional infiltration with doses ranging from 0.8 to 9 mg Sb/kg at the first infiltration. The C1 h ranged from 3850 to 47 095 mg × h/L and was the highest concentration obtained for 11 of 14 patients after the first intralesional infiltration of MA. A rapid initial phase of distribution lasting up to 4 h (2.6 ± 0.34 h) was followed by a slower elimination phase. Total skin lesion area, C1 h and AUC(0-6 h) were related to the dose of Sb infiltered (P < 0.05). Plasma Sb in samples collected weekly before the infiltration revealed antimony concentrations below the quantification limit (15.0 µg Sb/l) during the treatment period. CONCLUSIONS: Sb is quickly absorbed and eliminated after intralesional administration of MA, in a pattern similar to that reported with the Sb systemic administration. Using a therapeutic schedule limited to weekly intralesional infiltration of doses <10 mg Sb/kg does not result in plasma Sb accumulation.

Combined suboptimal schedules of topical paromomycin, meglumine antimoniate and miltefosine to treat experimental infection caused by Leishmania (Viannia) braziliensis.

OBJECTIVES: This study aimed to evaluate the efficacy of binary combinations of suboptimal schedules of drugs with different administration routes (topical paromomycin, intramuscular meglumine antimoniate and oral miltefosine) to treat animals infected with Leishmania (Viannia) braziliensis. METHODS: Hamsters were inoculated with L. (V.) braziliensis and after ulceration of lesions, divided into seven groups: untreated control, paromomycin, miltefosine, meglumine antimoniate, meglumine antimoniate + paromomycin, miltefosine + paromomycin and meglumine antimoniate + miltefosine. Meglumine antimoniate and miltefosine were administered at low doses and topical paromomycin at a single daily application regimen. The animals were treated for 20 consecutive days (meglumine antimoniate and/or paromomycin) and/or 10 alternate days (miltefosine). Lesion sizes were determined weekly. Upon completion of treatment, parasites were recovered from skin lesions and spleens and evaluated by limiting dilution assay. RESULTS: The combinations of a once daily application of paromomycin with low doses of miltefosine or meglumine antimoniate yielded higher efficacies in reducing the parasite load as well as lesion size when compared with any of these drugs administered as monotherapy regimens at the same suboptimal schedules. CONCLUSIONS: Considering the parameters evaluated, the combinations of a systemic therapy with topical treatment were more effective than monotherapy with each of these drugs. These combinations may represent an alternative combination strategy for the treatment of leishmaniasis caused by L. (V.) braziliensis.

Drug delivery systems for the topical treatment of cutaneous leishmaniasis.

INTRODUCTION: The parenteral administration of pentavalent antimonials for the treatment of all forms of leishmaniasis, including cutaneous leishamniasis (CL), has several limitations. Therapy is long, requiring repeated doses and the adverse reactions are frequent. Topical treatment is an attractive alternative for CL, offering significant advantages over systemic therapy: fewer adverse effects, ease of administration, and lower costs. AREAS COVERED: This review covers, from 1984 to the present, the progress achieved for the development of topical treatment for CL, using different drugs such as paromomycin (PA), imiquimod, amphotericin B (AmB), miltefosine, and buparvaquone. PA is the most commonly studied drug, followed by AmB and Imiquimod. These drugs were incorporated in conventional dosage forms or loaded in lipid nanocarries, which have been used mainly for improved skin delivery and antileishmanial activity. EXPERT OPINION: Developing an effective topical treatment for CL using these antileishmanial drugs still remains a great challenge. Insights into the most promising delivery strategies to improve treatment of CL with PA and AmB using conventional dosage forms, lipid nanocarriers, and combined therapy are presented and discussed. The results obtained with combined therapy and alternative delivery systems are promising perspectives for improving topical treatment of CL.

Reductions in skin and systemic parasite burdens as a combined effect of topical paromomycin and oral miltefosine treatment of mice experimentally infected with Leishmania (Leishmania) amazonensis.

This study aimed to investigate the activity of a combination of topical paromomycin gel and oral miltefosine for the treatment of experimental cutaneous leishmaniasis caused by Leishmania (Leishmania) amazonensis. The efficacy of the combination, evaluated by measuring lesion size and parasite burden in the skin and spleen, was assessed in BALB/c mice infected by L. (L.) amazonensis. The miltefosine was administered orally at 10 mg/kg of body weight/day for 10 days, while 10% paromomycin gel was applied topically twice a day for 20 days. Treatment of the experimentally infected animals with a topical paromomycin-oral miltefosine combination induced a statistically significant reduction in lesion size and parasite burden in the skin and spleen, with complete healing of ulcers, compared with those treated with a placebo group. A combination of topical paromomycin gel and oral miltefosine provided enhanced efficacy in the treatment of L. (L.) amazonensis-infected mice, showing activity higher than that observed for the monotherapeutic regimens.

Combined topical paromomycin and oral miltefosine treatment of mice experimentally infected with Leishmania (Leishmania) major leads to reduction in both lesion size and systemic parasite burdens.

OBJECTIVES: This study aimed to investigate the activity of the combination of topical paromomycin gel and oral miltefosine for the treatment of experimental cutaneous leishmaniasis caused by Leishmania (Leishmania) major. METHODS: The efficacy of the combination, evaluated by measuring lesion size and parasite burden in the skin and spleen, was assessed in BALB/c mice infected by L. (L.) major. Miltefosine was administered orally at 25 mg/kg/day for 10 days, while 10% paromomycin gel was applied topically twice a day for 10 days. RESULTS: Treatment of the experimentally infected animals with topical paromomycin + oral miltefosine combination induced a statistically significant reduction in lesion size and parasite burden in the skin, with complete healing of ulcers, as compared with those treated with oral miltefosine or placebo. Furthermore, topical paromomycin + oral miltefosine combination was as effective as topical paromomycin alone to reduce the lesion size and parasite load in lesions. However, the efficacy of the combination was significantly higher than that observed for the other treatments, including topical paromomycin alone, in reducing the parasite burden in spleen. CONCLUSIONS: The combination of topical paromomycin gel and oral miltefosine provides an enhanced efficacy in the treatment of L. (L.) major-infected mice, thus presenting a significantly higher activity than that observed for the monotherapeutic regimens.