Title:  Method for making a product adhere to a surface

United States Patent:  6,277,404

Assignee:  Capsulis (Pessac, FR)

Filed:  October 8, 1999

PCT NO:  PCT/FR98/00729

102(e) Date:  October 8, 1999

PCT PUB. Date:  October 22, 1998

Foreign Application Priority Data:  Apr 14, 1997[FR] (97 04548)

Method of making a product adhere to a surface, in which a composition is brought into contact with the surface, the composition containing the product incorporated in substantially spherical, multilamellar vesicles, with a diameter of between 0.1 and 100 .mu.m, and including concentric membranes based on at least one surfactant and separated by a solvent medium. Each of the vesicles has an onion-like structure formed of a succession of concentric bi-layers extending from each vesicle center to its periphery, and containing therein at least one cationic agent, resulting in the vesicles carrying a positive overall charge.

SUMMARY OF THE INVENTION

It has now been discovered that, provided they are formulated so as to have a positive overall charge, multilamellar microcapsules of onion-like structure, also called microvesicles or multilamellar vesicles below, possess the property of fixing themselves in a particularly stable manner to different surfaces and more particularly to the surface of natural or synthetic fibers or products based on such fibers, or to hair or to body hair/fur.

Multilamellar vesicles of "onion-like" structure are understood as meaning multilamellar vesicles of substantially spherical shape which consist of a series of concentric bilayers from the center to the periphery of the vesicles, which is why the term onion-like structure is used by analogy to qualify such structures.

These structures can be demonstrated by microscopic examination of the compositions. They are observed under a polarized light microscope, showing a birefringent lamellar phase. This exhibits a characteristic texture associated with the presence of defects (grain boundaries) between the differently orientated phase domains. In the case of the concentrated phase of vesicles, the texture is characterized by its fine uniform character relating to the size of the vesicles. In the disperse phase of vesicles, the latter are visible in the form of slightly birefringent dots of greater or lesser resolution (according to the size). The birefringence is observed only when the dispersion is not too dilute. Therefore, if the dispersion is relatively dilute, it will be necessary to concentrate it beforehand in order clearly to show the birefringence characteristic of the presence of the vesicles of onion-like structure.

It is quite obvious that in the present case, as in the case of the cationic liposomes described in international patent application WO 95/23578, the cationic charge on the liposomal entity or microcapsule is compensated at equilibrium by counterions. However, this charge can be demonstrated by measurements of zeta potentials made on a zeta meter. Such experiments are based on measurements of mobility in the presence of an electric field.

Claim 1 of 13 Claims

What is claimed is:

1. Method of making a product adhere to a surface, comprising bringing into contact with said surface a composition in which said product is incorporated in substantially spherical, multilamellar vesicles, with a diameter of between 0.1 and 100 .mu.m, and comprising concentric membranes based on at least one surfactant and separated by a solvent medium, each of said vesicles having an onion-like structure comprising a succession of concentric bi-layers extending from each vesicle center to its periphery, and containing therein at least one cationic agent, resulting in the vesicles carrying a positive overall charge.

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