ABSTRACT
RESUMEN Introducción: La N,N-dietil-m-metilbenzamida o N,N-dietil-m-toluamida (DEET), es muy conocida como repelente de insectos. Además, se utiliza para mejorar la administración dérmica y transdérmica de muchos fármacos. Objetivos: Presentar un procedimiento factible para sintetizar DEET a partir de ácido m-toluico y dietilamina. Métodos: El ácido m-toluico fue activado con 1,1'-carbonil-diimidazol, para obtener el producto intermedio 1- (m-toluoil) imidazol que continúa reaccionando con dietilamina, para producir DEET. De este modo, se mejoran los factores que afectan la síntesis de N, N-dietil-m-toluamida. Resultados: Se obtuvo DEET mediante un procedimiento óptimo. Los subproductos de la reacción son solubles en agua; se eliminan fácilmente mediante el método de extracción líquido-líquido con agua y diclorometano. La mayor parte del DEET obtenido tiene gran pureza. Los rendimientos fueron del 94 al 95 %. Conclusiones: Se ha proporcionado una ruta mejorada para una síntesis simple y eficaz de DEET a partir de ácido m-toluico y dietilamina en presencia de 1,1'-carbonil-diimidazol. El procedimiento de síntesis se realizó en un solo reactor y el aislamiento de DEET se logró mediante extracción líquido-líquido. El tiempo total de procedimiento se redujo significativamente. Este método de síntesis es fácilmente escalable y factible industrialmente.
ABSTRACT Introduction: N, N-diethyl-m-methylbenzamide or N, N-diethyl-m-toluamide (DEET), is well known as an insect repellent. In addition, it is used to improve the dermal and transdermal delivery of many drugs. Objectives: To present a feasible procedure to synthesize DEET from m-toluic acid and diethylamine. Methods: The m-toluic acid was activated with 1,1'-carbonyl-diimidazole, to obtain the intermediate product 1- (m-toluoyl) imidazole that continues to react with diethylamine, to produce DEET. In this way, the factors affecting the synthesis of N, N-diethyl-m-toluamide are improved. Results: DEET was obtained through an optimal procedure. The by-products of the reaction are soluble in water; they are easily removed by the liquid-liquid extraction method with water and dichloromethane. Most of the DEET obtained has high purity. The yields were 94 to 95 %. Conclusions: An improved route has been provided for a simple and efficient synthesis of DEET from m-toluic acid and diethylamine in the presence of 1,1'-carbonyl-diimidazole. The synthesis procedure was carried out in one-pot, and the isolation of DEET was achieved by liquid-liquid extraction. The total procedure time was significantly reduced. This synthesis method is easily scalable and industrially feasible.
ABSTRACT
ObjectiveTo explore the efficiency of N,N-diethyl-m-toluamide (DEET) with different concentrations in prevention of Schistosoma japonicum infection in mice.MethodsKunming-mice were randomly divided into four groups for the application of the vaseline ointment with different DEET concentrations (0,10%,20% and 30%). After the abdominal skin of the mice were smeared with those DEETs above mentioned and dipped into water for 10,30 min,1,2 h and 4 h, the mice were infected with (505) cercariae respectively. After infected for 6-7 weeks, all of the mice were sacrificed,and by perfusing heart the worms were collected and counted.Worm reduction rates were calculated and the rank sum tests were carried out. ResultsAt the time points of 1,2 and 4 h , the worm reduction rates were 78.34%,63.15% and 40.23% for 10% DEET vaseline ointment, 98.61%,93.37% and 75.74% for 20% DEET vaseline ointment and 100.00%,98.61% and 93.07% for 30% DEET vaseline oinment respectively(H =10.06,10.84,10.80,all P
ABSTRACT
Objective To compare the effica cy of three N,N-diethyl-m-toluamide (DEET) formulations against Schistosoma japonicum infection in mice. Methods Three 10% DEET formulations (DEET isopropanol solution,DEET cr eam and DEET vaseline ointment)were prepared and two experiments, no-dipping or dipping after applying DEET preparation ,were designed. In each experiment, mice were randomly divided into three experiment groups and three control groups . D ifferent DEET preparations were applied in the experiment groups and isopropanol solution, “yumeijing” cream , vaseline ointment were applied in the control g roups, respectively. At different time points after skin application (0.5, 1, 2 , 4 h and 8 h),the mice were infected with (50?5) Schistosoma j apon icum cercariae on the abdominal skin in no dipping experiment. I n dipping experiment,after mice skin were applied and were dipped for 10,30 min, 1 ,2 h and 4 h, respectively, the mice were infected with (50?5) cercariae. Af ter 6-7 weeks ,all the mice were sacrificed and the worms were collected by hea rt perfusion and counted.Worm reduction rates were calculated and rank sum tests w ere carried out. Results In no-dipping experim ent,three DEET formulations provided 100.0% protection in mice at least for 1 h .A t 2 ,4 h and 8 h ,the worm reduction rates were 94.8%,89.9% and 13.3% for DE ET isopropanol solution, 100.0%,97.8% and 50.7% for DEET cream and 100.0%,9 9.0% and 9 8.0% for DEET vaseline oinment, respectively. In dipping experi-ment, given 50.0% wor m reduction rate as efficient in preventing penetration by the cercariae, the e ffective times were 10 min for DEET isopropanol solution,30 min for DEET cream a nd 2 h for DEET vaseline oinment,respectively. Conclusion Three DEET formulations are effectiv e in preventing Schistosoma japonicum infection in mice.DEET vaseline oinment can provide better protection than the other two D EET formulations.