The efficacy of 2-nitrovinylfuran derivatives against Leishmania in vitro and in vivo

Despite recent advances in the treatment of some forms of leishmaniasis, the available drugs are still far from ideal due to inefficacy, parasite resistance, toxicity and cost. The wide-spectrum antimicrobial activity of 2-nitrovinylfuran compounds has been described, as has their activity against Trichomonas vaginalis and other protozoa. Thus, the aim of this study was to test the antileishmanial activities of six 2-nitrovinylfurans in vitro and in a murine model of leishmaniasis. Minimum parasiticide concentration (MPC) and 50% inhibitory concentration (IC50) values for these compounds against the promastigotes of Leishmania amazonensis, Leishmania infantum and Leishmania braziliensis were determined, as were the efficacies of two selected compounds in an experimental model of cutaneous leishmaniasis (CL) caused by L. amazonensis in BALB/c mice. All of the compounds were active against the promastigotes of the three Leishmania species tested. IC50 and MPC values were in the ranges of 0.8-4.7 µM and 1.7-32 µM, respectively. The compounds 2-bromo-5-(2-bromo-2-nitrovinyl)-furan (furvina) and 2-bromo-5-(2-methyl-2-nitrovinyl)-furan (UC245) also reduced lesion growth in vivo at a magnitude comparable to or higher than that achieved by amphotericin B treatment. The results demonstrate the potential of this class of compounds as antileishmanial agents and support the clinical testing of Dermofural(r) (a furvina-containing antifungal ointment) for the treatment of CL.

Incremento de disolución de un derivado del furano mediante la técnica de secado por atomización / Improvement of Furane derivate dissolution rate using spray drying technique

Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl)-furano (G1), un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica), 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray) a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.

Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl)-furane (G1), one pharmaceutically active ingredient with potent bactericidal and fungicidal action, synthesized through the preparation of solid dispersion macroparticles based on spray-drying process in the Center of Chemical Bioactives of the Central University in Las Villas province. Methods: a preliminary spray-drying test of GI suspension made up of 10 g of G1, 1g of Aerosil (Aerosil®, Degusa, Bélgica), 1g of sodium laurylsulphate and 100 ml of water was made. A piece of lab equipment known as Buchi Mini Dryer spray served for the spraying at 90 ºC. The solid dispersion was characterized from the physical and chemical viewpoints through X-ray diffraction, laser granulometry based on angular diffraction method, differential scanning calorimetry, electronic scanning microscopy and infrared spectrophotometry. Results: the obtained particles were small, spherical and had increased G1 crystallinity. No interactions were found in the dispersion components; there were no degradation products, and G1 solubility was significantly increased. Conclusions: the product obtained from spray-drying technique substantially raised the solubility of G1 without affecting the functional groups, which are responsible for the reported therapeutic action of the studied active ingredient. These encouraging results endorse the need for further studies to optimizing the process and carrying out stability tests for the product to be included in the pharmaceutical forms of dosing in the future.