Water-in-sorbitan monostearate organogels (water-in-oil gels)

doi:10.1021/js980343j

Journal of Pharmaceutical Sciences

Volume 88, Issue 6, June 1999, Pages 615-619

https://doi.org/10.1021/js980343j Get rights and content

Abstract

Novel multicomponent organogels containing an aqueous phase are described, and some properties which influence their potential as delivery devices for hydrophilic drugs and vaccines are discussed. The gel is produced by preparing a hot water-in-oil (w/o) emulsion using sorbitan monostearate, a nonionic surfactant which is also the organogelator, as the principal emulsifying agent. On cooling at room temperature, the w/o emulsion sets to an opaque, semisolid, thermoreversible organic gel. Cooling the emulsion results in a reduced solubility of the sorbitan monostearate in the oil, with a corresponding decrease in solvent–surfactant affinities, causing surfactant self-assembly into aggregates. The microstructure of the w/o gel is seen by light microscopy to consist of a network of tubules and fibrils (containing the aqueous phase) dispersed in the organic medium. X-ray diffraction and freeze-fracture studies suggest that the tubular aggregates in the w/o gel are made up of surfactant molecules arranged in inverted bilayers and that the aqueous phase is accommodated within these inverted bilayers, bound by the polar headgroups of the surfactant molecules. The presence of water in the tubular skeleton of the organic gels results in the establishment of percolating electroconductive aqueous channels in the organogel. Increasing the water content of a w/o gel causes the surfactant tubules to swell with a corresponding increase in conductivity until the tubules are saturated. Further increase in the water content results in the excess water accumulating in droplets within the organic medium and a decrease in conductivity as the gel integrity is compromised. The w/o gels (containing a model antigen, radiolabeled bovine serum albumin, in the aqueous phase) have demonstrated depot properties after intramuscular administration to mice, entrapped antigen being released over a period of days.

REFERENCES and NOTES (18)

W.L. Hinze et al.
Analytical and related applications of organogels
Curr. Opin. Colloid Interface Sci.
(1996)
H. Willimann et al.
Lecithin organogel as matrix for transdermal transport of drugs
J. Pharm. Sci.
(1992)
M.G. Nascimento et al.
Enzyme-catalysed esterifications in microemulsion-based organo gels
Tetrahedron Lett.
(1992)
R. Scartazzini et al.
Reactivity of lipase in an optically transparent lecithin-gel matrix
Biocatalysis
(1990)
H. Stamatis et al.
Esterification reactions catalyzed by lipases in microemulsions -the role of enzyme localization in relation to its selectivity
Biotech. Bioeng.
(1993)
G.D. Rees et al.
Use of water-in-oil microemulsions and gelatin-containing micro-emulsion-based gels for lipase-catalysed ester synthesis in organic solvents
Indian J. Chem.
(1993)
P.C. De Jesus et al.
Enzymatic resolution of alcohols via lipases immobilised in microemulsion-based gels
Tetrahedron Asymmetry
(1995)
T.R.J. Jenta et al.
Biocatalysis using gelatin microemulsion-based organogels containing immobilized chromobacterium viscosum lipase
Biotechnol. Bioeng.
(1997)
X.D. Xu et al.
Formation of novel organogels by the addition of phenols to AOT micelles in isooctane
J. Phys. Chem.
(1993)

There are more references available in the full text version of this article.

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^†: University of London

^‡: Leiden University.

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Research ArticlesWater-in-sorbitan monostearate organogels (water-in-oil gels)

Abstract

Curr. Opin. Colloid Interface Sci.

J. Pharm. Sci.

Tetrahedron Lett.

Reactivity of lipase in an optically transparent lecithin-gel matrix

Biocatalysis

Esterification reactions catalyzed by lipases in microemulsions -the role of enzyme localization in relation to its selectivity

Biotech. Bioeng.

Use of water-in-oil microemulsions and gelatin-containing micro-emulsion-based gels for lipase-catalysed ester synthesis in organic solvents

Indian J. Chem.

Enzymatic resolution of alcohols via lipases immobilised in microemulsion-based gels

Tetrahedron Asymmetry

Biocatalysis using gelatin microemulsion-based organogels containing immobilized chromobacterium viscosum lipase

Biotechnol. Bioeng.

Formation of novel organogels by the addition of phenols to AOT micelles in isooctane

J. Phys. Chem.

Research Articles
Water-in-sorbitan monostearate organogels (water-in-oil gels)