Thermoresponsive Leishmanicidal Emulgel Based on Copaifera reticulata Ducke: in Vitro Studies with the Amastigote Forms

Leishmaniasis is a neglected disease that causes disfiguring skin damage. In a previous publication, we characterized a thermoresponsive medicine developed for the dermal release of the Copaifera reticulata Ducke. The medicine showed chemical and physical stability for two years, proven by validation studies. Furthermore, the topical medicine undergoes gelation when body-stimulated, which increases the time spent on the injured skin. The present study aims to complement the characterization of the developed medicine by showing the in vitro results against amastigote forms of Leishmania amazonensis and Leishmania infantum. The results showed a notable antiproliferative capacity, especially against L. infantum, due to the excellent selectivity of the copaiba oil by the protozoan. Furthermore, the drugs were more effective than pure copaiba oil, with lower IC50 values for the incorporated oils, since the IC50 of the incorporated oil and the free oil decreased more than fourfold (from 14.8 to 3.4 μg/mL for phytotherapeutic gel containing 8 % w/w copaiba oil resin - named PHY-8). These results, together with those recently published for these formulations, guarantee the medicine's potential as a leishmanicidal agent and make it a potential candidate for future in vivo studies.