Coexisting Aggregates in Mixed Aerosol OT and Cholesterol Microemulsions

Sedgwick, Myles; Trujillo, Alejandro M.; Hendricks, Noah; Levinger, Nancy E.; Crans, Debbie C.

doi:10.1021/la103875w

Cited by 30 publications

(26 citation statements)

References 75 publications

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“…5 are characteristic for cholesterol [66], and randomly shaped structures are likely cholesterol and surfactant aggregates. Aggregates of cholesterol have previously been reported to form in AOT solutions with cholesterol in isooctane [67]. Summarizing, we have documented gel-phase formation in the 3 : 1 mixture of AOT and lecithin surfactant blend.…”

Section: Probing the Interaction Of Carboplatin With Dppc And Cholestsupporting

confidence: 68%

Gel Formulation Containing Mixed Surfactant and Lipids Associating with Carboplatin

Woll

Schuchardt

Willis

et al. 2011

Chemistry & Biodiversity

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The interaction of amphiphilic molecules such as lipids and surfactants with the hydrophilic drug carboplatin was investigated to identify suitable self-assembling components for a potential gel-based delivery formulation. (1) H-NMR Studies in sodium bis(2-ethylhexyl) sulfosuccinate (aerosol-OT, AOT)-based reverse micelles show that carboplatin associates and at least partially penetrates the surfactant interface. Langmuir monolayers formed by dipalmitoyl(phosphatidyl)choline are penetrated by carboplatin. Carboplatin was found to also penetrate the more rigid monolayers containing cholesterol. A combined mixed surfactant gel formulation containing carboplatin and cholesterol for lymphatic tissue targeting was investigated for the intracavitary treatment of cancer. This formulation consists of a blend of the surfactants lecithin and AOT (1 : 3 ratio), an oil phase of isopropyl myristate, and an aqueous component. The phases of the system were defined within a pseudo-ternary phase diagram. At low oil content, this formulation produces a gel-like system over a wide range of H(2) O content. The carboplatin release from the formulation displays a prolonged discharge with a rate three to five times slower than that of the control. Rheological properties of the formulation exhibit pseudoplastic behavior. Microemulsion and Langmuir monolayer studies support the interactions between carboplatin and amphiphilic components used in this formulation. To target delivery of carboplatin, two formulations containing cholesterol were characterized. These two formulations with cholesterol showed that, although cholesterol does little to alter the phases in the pseudo-ternary system or to increase the initial release of the drug, it contributes significantly to the structure of the formulation under physiological temperature, as well as increases the rate of steady-state discharge of carboplatin.

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Section: Probing the Interaction Of Carboplatin With Dppc And Cholestsupporting

confidence: 68%

Gel Formulation Containing Mixed Surfactant and Lipids Associating with Carboplatin

Woll

Schuchardt

Willis

et al. 2011

Chemistry & Biodiversity

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“…90 All samples used in further studies were transparent, and formation of RMs was confirmed by using dynamic light scattering (Wyatt DynaPro Titan) and conductivity measurements as described previously 90. 93…”

Section: Methodsmentioning

confidence: 99%

“…[48,90] All samples used in further studies were transparent, and formation of RMs was confirmed by using dynamic light scattering (Wyatt Dy-naPro Titan) and conductivity measurements as described previously. [90,93] Sample preparation for EPR spectroscopy: Solutions of the 1:2 complex, [VO(dipic) 2 ] 2À , were prepared from aqueous solutions of VOSO 4 (2, 4, and 10 mm) and solid Na 2 dipic with a 25-fold molar ligand-to-metal ratio. The solution pH was adjusted to 7.3 AE 0.4 with small aliquots of NaOH and HCl.…”

Section: Methodsmentioning

confidence: 99%

Correlation of Insulin‐Enhancing Properties of Vanadium‐Dipicolinate Complexes in Model Membrane Systems: Phospholipid Langmuir Monolayers and AOT Reverse Micelles

Sostarecz

Gaidamauskas

Distin

et al. 2014

Chemistry A European J

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We explore the interactions of V(III) -, V(IV) -, and V(V) -2,6-pyridinedicarboxylic acid (dipic) complexes with model membrane systems and whether these interactions correlate with the blood-glucose-lowering effects of these compounds on STZ-induced diabetic rats. Two model systems, dipalmitoylphosphatidylcholine (DPPC) Langmuir monolayers and AOT (sodium bis(2-ethylhexyl)sulfosuccinate) reverse micelles present controlled environments for the systematic study of these vanadium complexes interacting with self-assembled lipids. Results from the Langmuir monolayer studies show that vanadium complexes in all three oxidation states interact with the DPPC monolayer; the V(III) -phospholipid interactions result in a slight decrease in DPPC molecular area, whereas V(IV) and V(V) -phospholipid interactions appear to increase the DPPC molecular area, an observation consistent with penetration into the interface of this complex. Investigations also examined the interactions of V(III) - and V(IV) -dipic complexes with polar interfaces in AOT reverse micelles. Electron paramagnetic resonance spectroscopic studies of V(IV) complexes in reverse micelles indicate that the neutral and smaller 1:1 V(IV) -dipic complex penetrates the interface, whereas the larger 1:2 V(IV) complex does not. UV/Vis spectroscopy studies of the anionic V(III) -dipic complex show only minor interactions. These results are in contrast to behavior of the V(V) -dipic complex, [VO2 (dipic)](-) , which penetrates the AOT/isooctane reverse micellar interface. These model membrane studies indicate that V(III) -, V(IV) -, and V(V) -dipic complexes interact with and penetrate the lipid interfaces differently, an effect that agrees with the compounds' efficacy at lowering elevated blood glucose levels in diabetic rats.

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“…[61] Cuvettes were washed with ethanol, then with doubly distilled water, and then dried with acetone. The cleanliness of the cuvettes used for measurements was of crucial importance for obtaining reliable and reproducible data.…”

Section: Generalmentioning

confidence: 99%

Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants

Villa¹,

Silber²,

Correa³

et al. 2014

ChemPhysChem

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The behavior of water entrapped in reverse micelles (RMs) formed by two catanionic ionic liquid-like surfactants, benzyl-n-hexadecyldimethylammonium 1,4-bis-2-ethylhexylsulfosuccinate (AOT-BHD) and cetyltrimethylammonium 1,4-bis-2-ethylhexylsulfosuccinate (AOT-CTA), was investigated by using dynamic (DLS) and static (SLS) light scattering, FTIR, and (1)H NMR spectroscopy techniques. To the best of our knowledge, this is the first report in which AOT-CTA has been used to create RMs and encapsulate water. DLS and SLS results revealed the formation of RMs in benzene and the interaction of water with the RM interface. From FTIR and (1)H NMR spectroscopy data, a difference in the magnitude of the water-catanionic surfactant interaction at the interface is observed. For the AOT-BHD RMs, a strong water-surfactant interaction can be invoked whereas for AOT-CTA this interaction seems to be weaker. Consequently, more water molecules interact with the interface in AOT-BHD RMs with a completely disrupted hydrogen-bond network, than in AOT-CTA RMs in which the water structure is partially preserved. We suggest that the benzyl group present in the BHD(+) moiety in AOT-BHD is responsible for the behavior of the catanionic interface in comparison with the interface created in AOT-CTA. These results show that a simple change in the cationic component in the catanionic surfactant promotes remarkable changes in the RMs interface with interesting consequences, in particular when using the systems as nanoreactors.

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Coexisting Aggregates in Mixed Aerosol OT and Cholesterol Microemulsions

Cited by 30 publications

References 75 publications

Gel Formulation Containing Mixed Surfactant and Lipids Associating with Carboplatin

Gel Formulation Containing Mixed Surfactant and Lipids Associating with Carboplatin

Correlation of Insulin‐Enhancing Properties of Vanadium‐Dipicolinate Complexes in Model Membrane Systems: Phospholipid Langmuir Monolayers and AOT Reverse Micelles

Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants

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