Probing the microstructure of liquid crystalline surfactant systems; a physicochemical study using rheometry, DTA and 17O NMR

Tiemessen, H. L. G. M.; Maarel, Johan R. C. van der; Boddé, Harry E.; Jousma, H.; Junginger, Hans E.

doi:10.1016/0168-3659(90)90076-6

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…It was reported that a mixture of water and nonionic surfactant, Brij 96 (poly[oxyethylene(10) oleyl ether]) possibly exhibits a variety of liquid-crystalline structures such as lamellar, viscous isotropic, and hexagonal gel, depending on the mixing ratio. 23 The different liquid-crystalline phases demonstrated different diffusion coefficients for a particular drug due to changes in the morphology of the aqueous porosities and tortuosities. Protein release from the above liquid-crystalline phase should occur via arrays of hydrophilic and aqueous pores created by the selfassembled hydrophobic domains.…”

Section: Resultsmentioning

confidence: 99%

Poly(L-lactic acid)/Pluronic blends: characterization of phase separation behavior, degradation, and morphology and use as protein-releasing matrixes

Park¹,

Cohen²,

Langer³

1992

Macromolecules

216

137

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Section: Resultsmentioning

confidence: 99%

Poly(L-lactic acid)/Pluronic blends: characterization of phase separation behavior, degradation, and morphology and use as protein-releasing matrixes

Park¹,

Cohen²,

Langer³

1992

Macromolecules

216

137

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“…Telephone: (412) 396-5133; Email: adeyeyechri@duq.edu Microstructural characteristics (e.g, lamellar gel phase, interfacial layer or membrane of the dispersed phase, micellar formation and physical stability, flocculation, ratio of free and bound water to surfactants) of topical creams-pharmaceutical, cosmetic, or food-have been evaluated using several analytical methods. These methods include viscoelastic measurements [1][2][3][4], low-and highangle X-ray diffractometry [2], confocal laser scanning microscopy [5], thermogravimetry [6], low-temperature scanning electron microscopy [1,7,8], differential scanning calorimetry [9], and 17 O nuclear magnetic relaxation [10]. More microstructure investigations have focused on foods than on pharmaceuticals.…”

Section: *Corresponding Author: Moji Christianah Adeyeyementioning

confidence: 99%

Viscoelastic evaluation of topical creams containing microcrystalline cellulose/sodium carboxymethyl cellulose as stabilizer

et al. 2002

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The purpose of this study was to examine the viscoelastic properties of topical creams containing various concentrations of microcrystalline cellulose and sodium carboxymethyl cellulose (Avicel(R) CL-611) as a stabilizer. Avicel CL-611 was used at 4 different levels (1%, 2%, 4%, and 6% dispersion) to prepare topical creams, and hydrocortisone acetate was used as a model drug. The viscoelastic properties such as loss modulus (G"), storage modulus (G'), and loss tangent (tan delta) of these creams were measured using a TA Instruments AR 1000 Rheometer and compared to a commercially available formulation. Continuous flow test to determine the yield stress and thixotropic behavior, and dynamic mechanical tests for determining the linear viscosity time sweep data, were performed. Drug release from the various formulations was studied using an Enhancer TM Cell assembly. Formulations containing 1% and 2% Avicel CL-611 had relative viscosity, yield stress, and thixotropic values that were similar to those of the commercial formulation. The elastic modulus (G') of the 1% and 2% formulation was relatively high and did not cross the loss modulus (G"), indicating that the gels were strong. In the commercial formulation, G' increased after preshearing and broke down after 600 seconds. The strain sweep tests showed that for all formulations containing Avicel CL-611, the G' was above G" with a good distance between them. The gel strength and the predominance of G' can be ranked 6% > 4% > 2%. The strain profiles for the 1% and 2% formulations were similar to those of the commercial formulation. The delta values for the 1% and 2% formulations were similar, and the formulations containing 4% Avicel CL-611 had lower delta values, indicating greater elasticity. Drug release from the commercial preparation was fastest compared to the formulations prepared using Avicel CL-611, a correlation with the viscoelastic properties. It was found that viscoelastic data, especially the strain sweep profiles of products containing Avicel CL-611 1% and 2%, correlated with the commercial formulation. Rheological tests that measure the viscosity, yield stress, thixotropic behavior, other oscillatory parameters such as G' and G" are necessary tools in predicting performance of semisolids.

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The intramolecular OH bond length of water in a concentrated poly(ethyleneoxide) solution. An NMR relaxation study

Bieze

Maarel

Leyte

1993

Chemical Physics Letters

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Probing the microstructure of liquid crystalline surfactant systems; a physicochemical study using rheometry, DTA and 17O NMR

Cited by 4 publications

References 22 publications

Poly(L-lactic acid)/Pluronic blends: characterization of phase separation behavior, degradation, and morphology and use as protein-releasing matrixes

Poly(L-lactic acid)/Pluronic blends: characterization of phase separation behavior, degradation, and morphology and use as protein-releasing matrixes

Viscoelastic evaluation of topical creams containing microcrystalline cellulose/sodium carboxymethyl cellulose as stabilizer

The intramolecular OH bond length of water in a concentrated poly(ethyleneoxide) solution. An NMR relaxation study

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