RESUMEN
The advent of nanotechnology has led to an increased interest in nanocarriers as a drug delivery system that is efficient and safe. There have been many studies addressing nano-scale vesicular systems such as liposomes and niosome is a newer generation of vesicular nanocarriers. The niosomes provide a multilamellar carrier for lipophilic and hydrophilic bioactive substances in the self-assembled vesicle, which are composed of non-ionic surfactants in conjunction with cholesterol or other amphiphilic molecules. These non-ionic surfactant vesicles, simply known as niosomes, can be utilized in a wide variety of technological applications. As an alternative to liposomes, niosomes are considered more chemically and physically stable. The methods for preparing niosomes are more economic. Many reports have discussed niosomes in terms of their physicochemical properties and applications as drug delivery systems. As drug carriers, nano-sized niosomes expand the horizons of pharmacokinetics, decreasing toxicity, enhancing drug solvability and bioavailability. In this review, we review the components and fabrication methods of niosomes, as well as their functionalization, characterization, administration routes, and applications in cancer gene delivery, and natural product delivery. We also discuss the limitations and challenges in the development of niosomes, and provide the future perspective of niosomes.
RESUMEN
A simple electromembrane extraction (EME) procedure combined with ion chromatography (IC) was developed to quantify inorganic anions in different pure water samples and water miscible organic solvents. The parameters affecting extraction performance, such as supported liquid membrane (SLM) solvent, extraction time, pH of donor and acceptor solutions, and extraction voltage were optimized. The optimized EME conditions were as follows: 1-heptanol was used as the SLM solvent, the extraction time was 10 min, pHs of the acceptor and donor solutions were 10 and 7, respectively, and the extraction voltage was 15 V. The mobile phase used for IC was a combination of 1.8 mM sodium carbonate and 1.7 mM sodium bicarbonate. Under these optimized conditions, all anions had enrichment factors ranging from 67 to 117 with RSDs between 7.3 and 13.5% (n = 5). Good linearity values ranging from 2 to 1200 ng/mL with coefficients of determination (R(2) ) between 0.987 and 0.999 were obtained. The LODs of the EME-IC method ranged from 0.6 to 7.5 ng/mL. The developed method was applied to different samples to evaluate the feasibility of the method for real applications.
Asunto(s)
Aniones/análisis , Cromatografía por Intercambio Iónico/métodos , Técnicas Electroquímicas/métodos , Solventes/química , Agua/química , Concentración de Iones de Hidrógeno , Membranas Artificiales , Compuestos Orgánicos/químicaRESUMEN
A novel membrane coated platinum-wire electrode (MCPWE) based on N,N'-bis(2-thienylmethylene)-1,2-diaminobenzene (BTMD) for highly selective determination of Ag+ ion has been developed. The influences of membrane composition and pH on the potentiometric responses of electrode were investigated. The potentiometric responses are independent of the pH of the test solution in the range of 5.0 - 9.0. The electrode shows a linear response for Ag+ ion over the concentration range of 1.0 x 10(-60 to 1.0 x 10(-1) M with a lower detection limit of 6.0 x 10(-7) M. The electrode possesses a Nernstian slope of 59.7 mV decade(-1) and a fast response time of < or = 17 s and can be used for at least 2 months without any observable deviation. The proposed electrode displayed very good selectivity for Ag+ ion with respect to NH4+ and alkali, alkaline earth and some common transition metal ions. The practical utility of the electrode has been demonstrated by its use as the indicator electrode in the potentiometric titration of an AgNO3 solution with a NaI solution and in determination of the silver content of a developed radiological film.