Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Liposomes
Reexamination Certificate
1999-10-08
2001-08-21
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Liposomes
C424S400000
Reexamination Certificate
active
06277404
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of making a product adhere to a surface.
It further relates to the applications of such a method in different fields depending on the nature of the surface and that of the product.
It is very particularly applicable to the treatment of biological surfaces such as human skin or hair, animal skin or fur or the cuticle of plants or insects.
It is also applicable to the treatment of fibers, both natural and artificial, and to fiber-based products such as fabrics.
Different fields of industry are known where it is sought to improve the interaction between a product and a surface or to fix a product to a surface, either in order to improve the state of this surface or in order to subject it to a particular treatment. Particular possible applications are those where it is sought to modify the properties of a surface by subjecting it to a particular treatment with a product which needs to remain in contact with this surface for a sufficiently long time.
It is often useful to be able to treat fibers or textile or natural surfaces in order to improve their appearance (brightness, color, fragrance, etc.) or their properties (wear resistance, elasticity, slip, etc.) or in order to give them new functions.
In the case of skin, body hair/fur and hair, it is often sought to apply active agents thereto which medicate, treat or fortify it, for example.
In general terms, “active agent” or “active product” will be used indiscriminately below to denote the product which it is desired to fix to a surface.
One of the problems encountered in these various treatments is to ensure that the product persists on the surface, whether it be an inert surface or a biological surface such as the skin, body hair/fur, hair or integuments of living beings or the surface or cuticle of plants. Very often, the treatment is applied by means of a chemical reaction or by physicochemical adsorption (for example dyeing) during the manufacture of the fiber, or by means of a treatment requiring a special application in the case of human hair.
If an attempt is made to apply the treatment during a washing operation or when shampooing, for example, the main problem encountered is the fact that the active agent delivered by the shampoo or the detergent product, which is rinsed off, is very largely lost, only a tiny fraction remaining fixed to the treated surface. The persistence is therefore low, even if the proportion of active agent in the product is high. The same type of problem can arise if the treated surface is then exposed to the action of rain, for example.
Microencapsulation is a solution commonly used to prolong the period of availability of an active agent by only releasing it slowly. It is usually effected by forming a polymer shell around the active principle, either by spraying the active agent in the presence of a polymer or by one of the numerous encapsulation methods developed in industry, such as the various techniques of coacervation, atomization and coprecipitation. Liposomes can also be used, but their low stability and their cost prevent them from being used industrially.
International patent application WO 95/23578 describes the use of cationic liposomes for depositing an active ingredient on hair. The main problem presented by such liposomes is that the technique used to prepare them, which is simply to add the components of the liposomal membrane to the solution of active agent, does not easily allow control over the degree of encapsulation, which in any case is always low. Furthermore, only water-insoluble active agents can be encapsulated in such liposomes, thereby considerably limiting the list of active products suitable for use in such a technique.
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.
REFERENCES:
patent: 5264618 (1993-11-01), Felgner et al.
patent: 5610201 (1997-03-01), Grollier et al.
patent: 0457910 (1991-11-01), None
patent: 59-210013 (1984-11-01), None
patent: 90/06747 (1990-06-01), None
patent: 92/19214 (1992-12-01), None
patent: 93/19735 (1993-10-01), None
patent: 95/23578 (1995-09-01), None
patent: 96/31196 (1996-10-01), None
Degert Corinne
Laversanne Rene
Roux Didier
Capsulis
Dees Jose′ G.
Dennison, Scheiner Schultz & Wakeman
George Konata M.
LandOfFree
Method for making a product adhere to a surface does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for making a product adhere to a surface, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for making a product adhere to a surface will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2471080