RESUMO
Chagas' disease is a parasitic infection caused by Trypanosoma cruzi that is still treated by old and toxic drugs. In the search for novel alternatives, natural sources are an important source for new drug prototypes against T. cruzi to further structural exploitation. A set of natural-based compounds (LINS03) was designed, showing promising antitrypanosoma activity and low cytotoxicity to host cells. In this paper, nine novel LINS03 derivatives were evaluated against T. cruzi trypomastigotes and amastigotes. The selectivity was assessed through cytotoxicity assays using NCTC mammalian cells and calculating the CC50/IC50 ratio. The results showed that compounds 2d and 4c are noteworthy, due their high activity against amastigotes (IC50 13.9 and 5.8⯵M) and low cytotoxicity (CC50 107.7⯵M and >200⯵M, respectively). These compounds did not showed alteration on plasma membrane permeability in a Sytox green model. SAR analysis suggested an ideal balance between hydrosolubility and lipophilicity is necessary to improve the activity, and that insertion of a meta-substituent is detrimental to the activity of the amine derivatives but not to the neutral derivatives, suggesting different mechanisms of actions. The results presented herein are valuable for designing novel compounds with improved activity and selectivity to be applied in future studies.
Assuntos
Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/químicaRESUMO
The Phase Inversion Temperature of a reference C10E4/n-Octane/Water system exhibits a quasi-linear variation versus the mole fraction of a second surfactant S2 added in the mixture. This variation was recently proposed as a classification tool to quantify the Hydrophilic-Lipophilic Balance (HLB) of commercial surfactants. The feasibility of the so-called PIT-slope method for a wide range of well-defined non-ionic and ionic surfactants is investigated. The comparison of various surfactants having the same dodecyl chain tail allows to rank the polar head hydrophilicity as: SO3Na⩾SO4Na⩾NMe3Br>E2SO3Na≈CO2Na⩾E1SO3Na⩾PhSO3Na>Isosorbide(exo)SO4Naâ«IsosorbideendoSO4Naâ«E8⩾NMe2O>E7>E6⩾Glucosyl>E5⩾Diglyceryl⩾E4>E3>E2≈Isosorbide(exo)>Glyceryl>Isosorbide(endo). The influence on the surfactant HLB of other structural parameters, i.e. hydrophobic chain length, unsaturation, replacement of Na(+) by K(+) counterion, and isomerism is also investigated. Finally, the method is successfully used to predict the optimal formulation of a new bio-based surfactant, 1-O-dodecyldiglycerol, when performing an oil scan at 25 °C.
RESUMO
La ciclosporina A (CsA) por sus propiedades inmunosupresoras es empleada en el transplante de órganos sólidos, médula ósea, así como para determinados estadíos de ciertas enfermedades autoinmunes. En Cuba, se comercializa una solución oral que presenta problemas de absorción gastrointestinal. Objetivos: lograr una microemulsión preconcentrada conteniendo ciclosporina A con alto grado de dispersión, igual o mayor que la formulación comercial. Métodos: se realizó un estudio de porcentajes de los emulgentes y el balance hidrófilo lipófilo (HLB), en los intervalos que permitieran obtener sistemas automicroemulsionables a través de un diseño factorial multinivel. Se empleó el porciento de transmitancia como variable de respuesta en la determinación del grado de dispersión de la formulación. También se realizó la evaluación de las características organolépticas de la formulación seleccionada, el estudio reológico, el conteo microbiano y la efectividad antimicrobiana. Resultados: los factores estudiados tienen influencia significativa sobre el porcentaje de transmitancia, la formulación con mayor grado de dispersión se logró empleando un 60 por ciento de emulgentes junto a un HLB de 11,5 con valores de transmitancia de 95,03 por ciento, significativamente mayor que el del producto líder en formato de cápsulas blandas que fue de 84,6 por ciento. Organolépticamente el producto cumple con las características de líquido transparente, brillante y sin partículas en suspensión, con comportamiento Newtoniano desde el punto de vista reológico. El conteo de bacterias y hongos cumplió con los requisitos establecidos en la Farmacopea de los Estados Unidos para soluciones orales. Conclusiones: se logró una microemulsión preconcentrada de CsA en solución bebible con alto grado de dispersión, cumpliendo con los requisitos físicos y microbiológicos establecidos para este tipo de forma farmacéutica
Cyclosporine A (CsA), due to its immunosuppressive properties, is used in the transplantation of solid organs, bone marrow, and in some stages of certain autoimmune diseases. In Cuba, the Cyclosporine A oral solution causes gastrointestinal absorption problems. Objectives: to achieve a pre-concentrated micro-emulsion containing highly dispersed cyclosporine A that may be equal to or higher than the one in the commercial formulation. Methods: study of percentages of emulsifiers and of hydrophilic lipophilic balance (HLB), at some intervals that allow obtaining self-emulsifying systems through a multilevel factorial design. The percent transmittance was used as the response variable in determining the formulation dispersion degree. The evaluation of the organoleptic characteristics of the selected formulation, the rheological study, the microbial count and the antimicrobial effectiveness estimation were all performed. Results: the studied factors have a significant influence on the transmittance percentage, the formulation with the highest degree of dispersion was achieved when using 60 percent of emulsifiers and an HLB of 11.5, being transmittance values of 95.03 percent, which were significantly higher than those of the leading product in the form of soft capsules, equal to 84.6 percent. Organoleptically speaking, the product meets the characteristics of a clear brilliant fluid without suspended particles and Newtonian behavior from the rheological point of view. The bacteria and fungi count met requirements of U.S. Pharmacopoeia for oral solutions. Conclusions: a pre-concentrate highly dispersed CsA microemulsion was achieved in a drinkable solution meeting the physical requirements and microbiological criteria established for this type of dosage form
Assuntos
Ciclosporina/farmacologia , Emulsões , ImunossupressoresRESUMO
The aim of this work was to develop a methodology for rapid determination of the critical hydrophilic-lipophilic balance (HLB) value of lipophilic fractions of emulsions. The emulsions were prepared by the spontaneous emulsification process with HLB value from 4.3 to 16.7. The preparations were stored at 2 different temperatures (25°C and 4°C) and their physicochemical behavior was evaluated by the micro-emultocrit technique and the long-term stability study. The experimental data show a reverse relationship between HLB values of the surfactant mixtures and emulsion stability. A close correlation between the results for both stability procedures was observed, suggesting the use of micro-emultocrit to predict stabilities of such systems. In addition, it was found that the critical HLB of the Mygliol 812 was 15.367.