Avaliação da estabilidade preliminar e eficácia de uma nanoemulsão contendo Anfotericina B para o tratamento experimental de leishmaniose tegumentar

• Ano de defesa: 2018
• Autor(a) principal: Izabela Mansur Alves
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Atividade em modelo animal; Leishmaniose tegumentar; Colesterol; Nanoemulsão; Estabilidade; Anfotericina b; Modelos animais em pesquisa; Nanoemulsões; Anfotericina B
• Link de acesso: http://hdl.handle.net/1843/BUOS-B4TMAF

Amphotericin B (AmB), second line drug on leishmaniasis treatment, has been associated with high adverse reaction incidence. Nanoemulsions (NE) are an attractive alternative since they are capable of reducing the drugs toxicity. Therefore, this study aimed to evaluate the preliminary stability of a previously described AmB-loaded NE (NE-AmB) and evaluate its efficacy on an experimental treatment for cutaneous leishmaniasis. The following parameters were evaluated by an NE-AmB stability study (4 ºC): total content determination, encapsulation efficiency (EE), particle size, zeta potential and AmB aggregation state (measured by UV-Visible spectroscopy and circular dichroism). The NE-AmB capacity to induce in vitro hemolysis of rabbit red blood cells was also evaluated, in comparison to Anforicin®. Finally, the NE-AmB activity on BALB/c mice experimentally infected with Leishmania (Leishmania) major was evaluated on the following groups: Anforicin® (1 mg/kg) and NE-AmB (1; 4; or 8 mg/kg/day), intravenously administered in five alternate days. After the end of the treatment, the parasitic load (lesion and spleen) and the lesion size were evaluated. The analytic method was optimized and validated, meeting the recommended specifications and furthermore being able to promote the separation between the AmB from its alkaline degradation products. The 0.5% cholesterol was fundamental to the formulation stability and to the maintenance of the AmB monomeric form. The stability study shows that NE-AmB 0.5% cholesterol is stable, with total content and EE above 90% and a slight increase in size, keeping the appropriate parameters for intravenous administration during the 180 days of evaluation. In addition, the formulation does not show aggregate species even after 260 days of stability. The Anforicin® in vitro hemolytic activity was significantly higher than that which can be observed for the NEAmB with maintained stability during the 180 days (p<0.05). The in vivo study shows that the 8 mg/kg/day dosage of NE-AmB was capable of stabilizing the lesion size and reducing the parasitic load on the spleen in comparison to the control group (p<0.05), however, there was no significant parasitic load reduction on the lesion (p<0.05). On the other hand, Anforicin® shows no activity on neither of the evaluated parameters (p>0.05) in comparison to the control group. Hence, the results found in this study indicates the NE potential on AmB transportation for the parenteral treatment of cutaneous leishmaniasis.