Use of silver nanoparticles to control Vibrio fluvialis in cultured angelfish Pterophyllum scalare.

Nanoparticles have multiple applications, among which is their use as antimicrobial agents in aquaculture. The objective of this work was to determine the antibacterial effect of silver nanoparticles (AgNPs) against Vibrio fluvialis in cultured angelfish Pterophyllum scalare. AgNPs were synthetized through chemical reduction and characterized by UV-visible and infrared spectroscopy. Particle size ranged from 60 to 170.8 nm, and scanning electron microscopy revealed cubic and spherical forms. A minimal inhibitory concentration of 222.5 ppm was determined, as well as inhibition halos between 8.66 and 14.3 mm. Inhibition of V. fluvialis growth was observed upon contact with AgNPs. An 88% survival of infected fish was obtained when treated with AgNPs, in contrast to 100% mortality of fish that were not treated. No damage to internal or external organs was observed in fish exposed to AgNPs. We conclude that AgNPs exert an antimicrobial effect against V. fluvialis, and thus represent a new alternative to control diseases caused by this microorganism in P. scalare culture.

Physicochemical characterization and thermal behavior of hexosomes containing ketoconazole as potential topical antifungal delivery system.

OBJECTIVE: The main purpose of this article is to show the valuable characteristics that liotropic liquid crystal systems possess to be employed as new drug delivery systems. SIGNIFICANCE: Colloidal aqueous dispersions of lyotropic liquid crystal mesophases such as the identified as cubosomes and hexosomes, and so on, have received considerable attention due to their unique nanostructures and their thermodynamic properties, which provide the potential as a sustained drug release matrix. Additionally, their large surface area and similarity with the liquid crystal structures of intercellular lipids of stratum corneum enhances the interaction with the skin and mucous, increasing the potential for topical drug delivery efficiency of biopharmaceutical class II drugs as the antifungal ketoconazole. METHODS: This article presents the results in morphological characteristics, particle size, ζ potential, flow, thermal behavior and drug release studies of hexosomes containing ketoconazole (LHLC-K) obtained with glycerol monooleate, propylene glycol monolaurate, poloxamer, and water mixtures. RESULTS: This colloidal system exhibits a Newtonian-type flow and a hexagonal nanostructure with a median particle size of 107 ± 20 nm and ζ potential of +4.45 ± 0.50 mV. Through differential scanning calorimetry studies, the LHLC-K demonstrated physical and chemical stability for more than six months and mesophasic thermal reversibility between 10 and 50 °C. Finally, LHLC-K releases ketoconazole following a kinetics described by the first order model. CONCLUSIONS: Physicochemical properties of the hexosomes containing ketoconazole are important for topical mycosis treatment administration, conditions of storage, and for its incorporation into the formulation of semi-solid dosage forms.

Caracterización fisicoquímica y evaluación in vitro de sistemas autoemulsionables de liberación de indometacina

Objetivo: incorporar la indometacina en sistemas autoemulsionables de liberación con la finalidad de aumentar su solubilidad en medio acuoso, la velocidad de disolución y permeación in vitro. Metodología: se llevaron a cabo ensayos de solubilidad al equilibrio para preparar formulaciones con los excipientes, en los cuales la indome-tacina presentó mayor incremento de solubilidad; los sistemas fueron caracterizados por medio del tiempo de autoemulsificación, estabilidad física, tamaño de partícula, potencial zeta, perfiles de disolución y permeación a través de membrana sintética. Resultados: el diseño experimental de los sistemas autoemulsionables de liberación permitió crear formulaciones que aumentaron la solubilidad de la indometacina en un orden de 105 veces con respecto a la solubilidad acuosa. Las formulaciones que resultaron viables presentaron tiempos de autoemulsificación menores que 60 segundos, además, las distribuciones de tamaño de partícula de las dispersiones fueron inferiores a los 300 nm, presentó índices de polidispersión inferiores a 0,3 y valores de potencial zeta menores de -25 mV. Los perfiles de disolución mostraron que las formulaciones cumplen con un valor de factor de similitud mayor que 50, además, la permeabilidad a través de membrana sintética es mayor para las formulaciones autoemulsionables que el producto de referencia. Conclusiones: la formulación de indometacina en sistemas autoemulsionables de liberación incrementa la solubilidad en medio acuoso, aumenta la disolución y liberación. Estos resultados sugieren que la administración oral de indometacina incorporada en sistemas autoe-mulsionables puede acelerar el inicio del efecto farmacológico.

SUMMARY Aim: To load indomethacin into self-emulsifying delivery systems in order to increase, water-solubility, rate dissolution and in vitro permeation. Methodology: Equilibrium solubility tests were carried out to prepare formulations with the excipients, in which indomethacin presented a greater increase in solubility; the systems were characterized by self-emulsification time, physical stability, particle size, zeta potential, dissolution profiles and permeation through synthetic membrane. Results: The experimental design of self-emulsifying delivery systems allowed to create formulations that increase the solubility of indomethacin in an order of 105 times with respect to the aqueous solubility. The feasible formulations presented autoemulsification times less than 60 seconds, in addition, the particle size distributions of the dispersions were less than 300 nm, with polydispersity index smaller than 0.3, and zeta potential values lower than -25 mV. The dissolution profiles showed that the formulations comply with a similarity factor value greater than 50, in addition, the permeability through a synthetic membrane is higher for the self-emulsifying formulations than the reference product. Conclusion: The formulation of indomethacin into self-emulsifying delivery systems enhances the solubility in aqueous medium, increases dissolution and accelerate release. These results suggest that the oral administration of indomethacin incorporated into self-emulsifying delivery systems can accelerate the onset of the pharmacological effect.

Objetivo: incorporar a indometacina em sistemas de liberação autoemulsificantes a fim de aumentar sua solubilidade em meio aquoso, a taxa de dissolução e permeação in vitro. Metodologia: foram realizados testes de solubilidade de equilíbrio para preparar formulações com os excipientes, nas quais a indometacina apresentou maior aumento na solubilidade; os sistemas foram caracterizados quanto ao tempo de autoemulsificação, estabilidade física, tamanho de partícula, potencial zeta, perfis de dissolução e permeação através de membrana sintética. Resultados: o desenho experimental dos sistemas de liberação autoemulsificantes permitiu a criação de formulações que aumentaram a solubilidade da indometacina na ordem de 105 vezes em relação à solubilidade aquosa. As formulações que se mostraram viáveis apresentaram tempos de autoemulsificação inferiores a 60 segundos, além disso, as distribuições granulométricas das dispersões foram inferiores a 300 nm, apresentaram índices de polidispersidade inferiores a 0,3 e valores de potencial zeta inferiores a -25 mV. Os perfis de dissolução mostraram que as formulações atendem a um valor de fator de similaridade maior que 50, além disso, a permeabilidade através da membrana sintética é maior para as formulações autoemulsionantes do que para o produto de referência. Conclusões: a formulação de indometacina em sistemas de liberação autoemulsificantes aumenta a solubilidade em meio aquoso, aumenta a dissolução e a liberação. Esses resultados sugerem que a administração oral de indometacina incorporada em sistemas autoemulsificantes pode acelerar o início do efeito farmacológico.