Structural Polymorphism in a Four-Component Nonionic Microemulsion

Ezrahi, S.; Wachtel, Ellen; Aserin, Abraham; Garti, Nissim

doi:10.1006/jcis.1997.4962

Cited by 57 publications

(52 citation statements)

References 68 publications

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“…Such a unidimensional expansion was also detected in our previous studies on concentrated microemulsions stabilized with ethoxylated surfactants (14,22). It suggests that the aggregate has a quasi-lamellar structure of surfactant and water, randomly oriented in the continuous oil phase.…”

Section: Resultssupporting

confidence: 55%

“…Water is never the external phase, as determined by color tests. It should be pointed out in addition that even in some microemulsion systems which do invert (21,22) no sharp increase in conductivity is observed at inversion. Fusion temperature of dodecanol.…”

Section: Resultsmentioning

confidence: 94%

“…On the basis of these results and studies carried out (13,14,22,26) microemulsion structure formed in these oils (Fig. 10).…”

Section: Resultsmentioning

confidence: 96%

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Water Solubilization in Nonionic Microemulsions Stabilized by Grafted Siliconic Emulsifiers

Garti

Aserin

Wachtel

et al. 2001

Journal of Colloid and Interface Science

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Section: Resultssupporting

confidence: 55%

Section: Resultsmentioning

confidence: 94%

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Water Solubilization in Nonionic Microemulsions Stabilized by Grafted Siliconic Emulsifiers

Garti

Aserin

Wachtel

et al. 2001

Journal of Colloid and Interface Science

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“…[29][30][31] However, the addition of salt, especially sodium chloride, can significantly affect the phase behaviors and structural properties of microemulsions, 4 and that even may result in phase separation. For this reason, in this study, the conductivity measurements were performed without deliberate incorporation of an electrolyte.…”

Section: Resultsmentioning

confidence: 99%

Comparison of different water/oil microemulsions containing diclofenac sodium: Preparation, characterization, release rate, and skin irritation studies

Kantarcı¹,

Özgüney²,

Karasulu³

et al. 2007

AAPS PharmSciTech

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The aim of the present study was to make a comparison of the in vitro release rate of diclofenac sodium (DS) from microemulsion (M) vehicles containing soybean oil, nonionic surfactants (Brij 58 and Span 80), and different alcohols (ethanol [E], isopropyl alcohol [I], and propanol [P]) as cosurfactant. The optimum surfactant:cosurfactant (S:CoS) weight ratios and microemulsion areas were detected by the aid of phase diagrams. Three microemulsion formulations were selected, and their physicochemical properties were examined for the pH, viscosity, and conductivity. According to the release rate of DS, M prepared with P showed the significantly highest flux value (0.059 ± 0.018 mg/cm 2 /h) among all formulations (P G .05). The conductivity results showed that DS-loaded microemulsions have higher conductivity values (18.8-20.2 microsiemens/cm) than unloaded formulations (16.9-17.9 microsiemens/cm), and loading DS into the formulation had no negative effect on system stability. Moreover, viscosity measurements were examined as a function of shear rate, and Newtonian fluid characterization was observed for each microemulsion system. All formulations had appropriate observed pH values varying from 6.70 to 6.85 for topical application. A skin irritation study was performed with microemulsions on human volunteers, and no visible reaction was observed with any of the formulations. In conclusion, M prepared with P may be a more appropriate formulation than the other 2 formulations studied as drug carrier for topical application.

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“…This unique oil differs from common vegetable oils and animal fats in that it is composed mainly (97%) of linear long-chain esters, which are characteristic components of waxes. More than 80% of these are esters of C 18 -, C 20 -, C 22 -, and C 24 -chain monounsaturated alcohols and acids (1).…”

mentioning

confidence: 99%

Formation and investigation of microemulsions based on jojoba oil and nonionic surfactants

Shevachman

Shani

Garti

2004

J Americ Oil Chem Soc

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The properties of jojoba oil make it uniquely suited as a raw material for the cosmetics industry. Water-based, thermodynamically stable preparations of jojoba oil are essential in many formulations. New microemulsions were prepared based on jojoba oil and different nonionic surfactants, namely polyoxyethylene-(ethylene oxide) 10 -oleyl alcohol (Brij 96V) and ethoxylated sorbitan esters (Tweens). The effects of the surfactants and of primary alcohols as cosurfactants on the isotropic regions of the phase diagram were elucidated. It was found that, up to a certain cosurfactant chain length, the isotropic region expanded considerably as chain length increased. The size of the isotropic region also increased as a function of the ethylene glycol content of the aqueous phase in microemulsions based on ethoxylated alcohol but shrank when ethylene glycol was included in microemulsions prepared with ethoxylated sorbitan esters. Secondary structural phase transitions from water-in-oil to bicontinuous and to oil-in-water structures (as determined by measuring conductivity and viscosity) were found to be related to jojoba oil content. Dynamic light scattering and small angle X-ray scattering studies established that incorporation of jojoba oil into Brij 96V micelles caused micellar transformation from elongated to spherical droplets and a decrease in the aggregation number.Jojoba liquid wax (also called jojoba oil) is a stable, highly lipophilic, non-toxic "oily" material obtained from the seeds of the desert plant jojoba (Simmondsia chinensis) (Fig. 1). This unique oil differs from common vegetable oils and animal fats in that it is composed mainly (97%) of linear long-chain esters, which are characteristic components of waxes. More than 80% of these are esters of C 18 -, C 20 -, C 22 -, and C 24 -chain monounsaturated alcohols and acids (1).Jojoba wax resists oxidation even at elevated temperatures and can remain chemically unchanged for years. Owing to its excellent ability to penetrate the skin and high resistance to oxidation, jojoba wax is widely used as a component in cosmetics. Its derivatives have potential applications in a variety of commercial fields, including pharmaceuticals and lubrication (1). Numerous recent studies have demonstrated the feasibility of incorporating jojoba as an oil phase in formulas containing active compounds to enhance the efficacy of topical drugs (2,3).The growing interest in microemulsions (ME) for cosmetic and pharmaceutical applications is linked to their physicochemical properties-thermodynamic stability, spontaneous formation, clear appearance, low viscosity, and high solubilization capacity (4). A particularly attractive possibility is that of using ME to enhance the efficacy of molecularly solubilized, hydrophobic, biologically active compounds by providing a readily controlled, stable medium for the solubilized components, together, perhaps, with protection against degradative reactions (5).The use of alcohols as cosurfactants in the preparation of ME has a long history. Alcoho...

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Structural Polymorphism in a Four-Component Nonionic Microemulsion

Cited by 57 publications

References 68 publications

Water Solubilization in Nonionic Microemulsions Stabilized by Grafted Siliconic Emulsifiers

Water Solubilization in Nonionic Microemulsions Stabilized by Grafted Siliconic Emulsifiers

Comparison of different water/oil microemulsions containing diclofenac sodium: Preparation, characterization, release rate, and skin irritation studies

Formation and investigation of microemulsions based on jojoba oil and nonionic surfactants

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