Extensive surface studies help to analyse zeta potential data: the case of cationic emulsions

Rabinovich‐Guilatt, Laura; Couvreur, Patrick; Lambert, Grégory; Goldstein, D. J.; Benita, Simon; Dubernet, Catherine

doi:10.1016/j.chemphyslip.2004.04.003

Cited by 62 publications

(28 citation statements)

References 44 publications

(68 reference statements)

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“…A elevação da temperatura aumenta a quantidade de choques moleculares e acelera a separação (o aumento da energia cinética impacta no equilíbrio termodinâmico). Para reduzir a probabilidade de coalescência, a cinética pode ser desacelerada com o aumento da viscosidade, tamanho uniforme das gotículas e solubilidade [4,7] . Detalhes são discutidos nos próximos itens.…”

Section: Formação De Micelasunclassified

“…Em um campo elétrico, como em microeletroforese, cada gotícula e os íons mais fortemente ligados à mesma se movem como uma unidade, e o potencial no plano de cisalhamento entre essa unidade e o meio circundante é chamado potencial zeta [7] .…”

Section: Forças De Interações Intermolecularesunclassified

“…Quanto maior o potencial zeta, mais provável que a suspensão seja estável, pois as gotículas carregadas se repelem umas às outras e essa força supera a tendência natural de agregação [2,3,7] .…”

Section: Forças De Interações Intermolecularesunclassified

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Estabilidade de emulsões: um estudo de caso envolvendo emulsionantes aniônico, catiônico e não-iônico

Franzol

Rezende

2015

Polímeros

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AesumoEste artigo explora conceitos teóricos que se apresentam como estratégica na formulação de emulsões. Emulsões são sistemas termodinamicamente instáveis e o objetivo de todo formulador é estabelecer critérios técnicos na escolha de componentes para atingir a estabilidade cinética. Estudos de décadas trazem lucidez para que melhores resultados sejam atingidos, na estabilização de sistemas emulsionados. Nesse sentido, este artigo faz uma exploração prática comparando três emulsionantes (aniônico, catiônico e não-iônico) nas concentrações de 1, 3 e 5% em massa, para um melhor entendimento da aplicação da química na escolha do tipo de emulsionante e sua concentração na proposição de um sistema emulsionado. A comparação realizada é baseada em medidas de tamanhos de gotículas de fórmulas preparadas. Os resultados apresentados ilustram a contribuição das características químicas das moléculas dos emulsionantes na estabilidade do sistema e também o quanto é importante o conhecimento prévio das teorias de emulsões (apresentadas neste artigo) para atingir o sucesso na obtenção de sistemas cineticamente estáveis. Palavras-chave: emulsão, estabilidade, tamanho de gotículas. AbstractThis article uses theoretical strategies for the design of emulsions formulation. Emulsions are considered as thermodynamically unstable systems and all formulators aim to establish the right technical criteria for choosing the right components and reach kinetic stability. Since some decades ago, theories were developed and this knowledge has contributed for better results involving the stabilization of emulsion systems. For a better understanding of the chemistry supporting the emulsifier selection and its concentration behind a stable system proposition, this article presents a practical application involving three different emulsifiers (anionic, cationic and nonionic) at 1, 3 and 5% in weight. The comparison is based on particle size analyses of droplets of the prepared formulas. The results show the contribution of the chemical characteristics of the emulsifiers on the system stabilization and the importance of prior knowledge of the emulsions theories (presented in this article) to succeed in obtaining kinetically stable systems.

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Section: Formação De Micelasunclassified

Section: Forças De Interações Intermolecularesunclassified

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Estabilidade de emulsões: um estudo de caso envolvendo emulsionantes aniônico, catiônico e não-iônico

Franzol

Rezende

2015

Polímeros

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“…Based on these results, one can conclude about the density and distribution of charges localized on membrane, possible surface shielding due to adsorption of organic and inorganic polar molecules (Rabinovich-Guilatt et al 2004;Patila et al 2007;Huynh et al 2009). Many physiological reactions at membranes depend on local ion concentration.…”

Section: Liposomesmentioning

confidence: 99%

Physicochemical techniques in description of interactions in model and native plant membranes under stressful conditions and in physiological processes

Rudolphi-Skórska

Sieprawska

2015

Acta Physiol Plant

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The diversity of chemical structure of lipids present in the cell membranes, concerning both a hydrophilic (polarity and charge) and hydrophobic (chain length and unsaturation of fatty acids residues) parts, assists in providing suitable physical and chemical properties for the course of multiple reaction within the membrane. This review presents the results of the changes in the lipid composition of native membranes of plant cells under stress conditions and during developmental processes. It also discussed the use of lipids to create model systems which allow for interpretation of specificity of reactions taking place in the membrane fragments. The spontaneous formation by lipids closed spherical structures (bi-layers) in an aqueous medium, and monolayers at the water/air interface creates a convenient model system for the native membranes. The review focuses on the techniques of electrokinetic potential (zeta potential) measurements and Langmuir monolayers' studies. The first gives the possibility to conclude about the modification of the polar part of the membranes, the second allows to determine their structural properties (fluidity, stiffness). The relatively rapid modification of the lipid composition under stress and during the course of developmental processes to ensure the optimal functions of membranes and organelles includes the changes of hydrophobic/hydrophilic character of lipid, as an important factor influencing the course of multiple reactions in cells. Understanding the physicochemical properties of lipids that accompany these processes may contribute to the correct description of the functionality of the cells under these conditions.

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“…For these formulations, final pH was adjusted to 5.0-6.0 to produce theoretically fully ionized OLA molecules at the interface, as previously reported. 37,38 Furthermore, it was demonstrated that the pH of the vehicle had a significant effect in the cutaneous retention of genistein, which is higher at a pH of 6.0, due the nonionic form of genistein in this medium. 39 For the optimized formulations, the genistein content values were higher than 95% (0.96±0.041 and 0.95±0.042 for NE1 and NE3, respectively), without any difference among them (P0.05).…”

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confidence: 99%

Factorial design applied to the optimization of lipid composition of topical antiherpetic nanoemulsions containing isoflavone genistein

Argenta¹,

Mattos²,

Misturini³

et al. 2014

IJN

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The aim of this study was to optimize topical nanoemulsions containing genistein, by means of a 2 3 full factorial design based on physicochemical properties and skin retention. The experimental arrangement was constructed using oil type (isopropyl myristate or castor oil), phospholipid type (distearoylphosphatidylcholine [DSPC] or dioleylphosphaditylcholine [DOPC]), and ionic cosurfactant type (oleic acid or oleylamine) as independent variables. The analysis of variance showed effect of third order for particle size, polydispersity index, and skin retention of genistein. Nanoemulsions composed of isopropyl myristate/DOPC/oleylamine showed the smallest diameter and highest genistein amount in porcine ear skin whereas the formulation composed of isopropyl myristate/DSPC/oleylamine exhibited the lowest polydispersity index. Thus, these two formulations were selected for further studies. The formulations presented positive ζ potential values (>25 mV) and genistein content close to 100% (at 1 mg/mL). The incorporation of genistein in nanoemulsions significantly increased the retention of this isoflavone in epidermis and dermis, especially when the formulation composed by isopropyl myristate/DOPC/oleylamine was used. These results were supported by confocal images. Such formulations exhibited antiherpetic activity in vitro against herpes simplex virus 1 (strain KOS) and herpes simplex virus 22 (strain 333). Taken together, the results show that the genistein-loaded nanoemulsions developed in this study are promising options in herpes treatment.

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Extensive surface studies help to analyse zeta potential data: the case of cationic emulsions

Cited by 62 publications

References 44 publications

Estabilidade de emulsões: um estudo de caso envolvendo emulsionantes aniônico, catiônico e não-iônico

Estabilidade de emulsões: um estudo de caso envolvendo emulsionantes aniônico, catiônico e não-iônico

Physicochemical techniques in description of interactions in model and native plant membranes under stressful conditions and in physiological processes

Factorial design applied to the optimization of lipid composition of topical antiherpetic nanoemulsions containing isoflavone genistein

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