Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Curcumin-loaded polymeric and lipid nanocapsules: preparation, characterization and chemical stability evaluation

Polymeric and lipid nanocapsules suspensions of the natural compound curcumin were prepared in order to overcome limitations associated with its clinical applications, such as poor aqueous solubility and susceptibility to hydrolytic and photochemical degradation. Nanocapsule suspensions were prepared by nanoprecipitation and phase inversion methods, respectively. The curcumin formulations were investigated for physicochemical characteristics and in vitro drug release. The hydrolytic and photochemical degradation of the drug associated with the nanocarriers was also determined. For all formulations, the entrapment efficiency values were higher than 99 %. The aqueous colloidal suspensions of curcumin resulted in an increase in drug concentration by a factor of up to 46.103 times. Moreover, stability studies indicated that nanoencapsulation slows down the hydrolytic and photochemical degradations of curcumin. The strategy of nanoencapsulation into polymeric and lipid nanocapsules produced a formulation of curcumin with high drug loading and improved stability, representing a good strategy for the delivery of this drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Estudo das dispersões aquosas de nanotubos de carbono utilizando diferentes surfactantes

The dispersion of carbon nanotubes in water for their utilization in nanoscale devices is a challenging task. Comparative studies on interaction and dispersion of multi-wall carbon nanotubes (MWNT) using two different surfactants (sodium dodecyl sulfate, SDS, and polyoxyethylenesorbitanmonooleate, Tween 80) are presented. The interaction between carbon nanotubes and surfactants was studied by tensiometry, conductivimetry, and fluorimetry. The dispersions of MWNT in surfactants were characterized using a UV-vis spectrophotometer. For effective dispersion, the minimum weight ratio of MWNT to surfactant was 1:41 and 1:3 for SDS and Tween 80, respectively

Estudo das dispersões aquosas de nanotubos de carbono utilizando diferentes surfactantes Study of aqueous dispersions of carbon nanotubes using different surfactants

The dispersion of carbon nanotubes in water for their utilization in nanoscale devices is a challenging task. Comparative studies on interaction and dispersion of multi-wall carbon nanotubes (MWNT) using two different surfactants (sodium dodecyl sulfate, SDS, and polyoxyethylenesorbitanmonooleate, Tween 80) are presented. The interaction between carbon nanotubes and surfactants was studied by tensiometry, conductivimetry, and fluorimetry. The dispersions of MWNT in surfactants were characterized using a UV-vis spectrophotometer. For effective dispersion, the minimum weight ratio of MWNT to surfactant was 1:41 and 1:3 for SDS and Tween 80, respectively

ASSOCIATION OF BRANCHED POLYETHYLENE IMINE WITH SURFACTANTS IN AQUEOUS SOLUTION

Three polymer-surfactant systems comprised of branched polyethylene imine (PEI) with an anionic surfactant (sodium dodecylsulfate; SDS), a cationic surfactant (tetradecyltrimethylammonium bromide; TTAB), and a zwitterionic surfactant (N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate; SB3-14) were studied based on the properties of surface tension, pyrene fluorescence emission, dynamic light scattering, pH, and zeta potential measurements. The critical aggregation concentration (cac) and polymer saturation point (psp) were determined for all three systems. The effect of these surfactants on the physico-chemical characteristics (diameter and surface charge) of the complexes formed was determined. Polymer-surfactant interactions occurred in all of the systems studied, with the strongest interactions, electrostatic in nature, occurring in the SDS-PEI system. After the neutralization of the polymer charges with the addition of the surfactant, the hydrophobic effect started to control the interlacing of the polymer chains. For the PEI-TTAB system, a very dense film was formed at surfactant concentrations above 2.0 mmol L-1. In this case, the bromide counter-ion interacted with both the positively-charged PEI and the head of the surfactant, which is responsible for the formation of double layer coordination complexes. For the system composed of PEI and the zwitterionic surfactant, less cooperative associations occurred in comparison with the other systems.</p

Formação de micelas mistas entre o sal biliar colato de sódio e o surfactante aniônico dodecanoato de sódio Mixed micelles formation between bile salt sodium cholate and the anionic surfactant sodium dodecanoate

<abstract language="eng">Mixed-micelle formation between sodium chlolate (NaC) and the anionic surfactant sodium dodecanoate (SDoD) in Tris-HCl buffer solutions, pH 9.00, varying the molar fraction of the surfactants, was investigated by means of electrical conductivity and steady-state fluorescence of pyrene. The critical micelar concentration (cmc) was measured from the equivalent conductance versus the square root of the molar surfactant concentration plots and the regular solution theory (RST) was used to predict the mixing behavior. The I1/I3 pyrene ratio-surfactant concentration plots were used as an additional technique to follow the behavior and the changes in the micropolarity of the mixed micelles