Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-05-02
2002-12-17
Krass, Frederick (Department: 1614)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C514S873000, C514S023000, C514S053000, C514S054000, C514S506000
Reexamination Certificate
active
06495147
ABSTRACT:
The invention relates to novel uses of D-xylose, esters thereof and oligosaccharides containing xylose for improving the functionality of epidermal cells.
It relates more precisely to novel uses of these products in the field of cosmetics and pharmacy, especially dermatology, for improving this functionality by stimulating the synthesis of proteoglycans and/or glycosaminoglycans.
Throughout the present statement, proteoglycans will be denoted by the abbreviation PG and glycosaminoglycan is by the abbreviation GAG.
If it is desired to improve skin hydration, it is possible to employs products whose action is associated with:
either an occlusive effect: this property makes it possible to regulate the water loss b) creating a barrier which opposes the passage of water molecules;
or a humectant effect: these products act bad hygroscopic;
or a keratiniocyte differentiation effect leading to skin hydration: this action culminates in the formation of corneocytes, particularly the corneocyte envelope, and to the formation of substances synthesized by keratinocytes during their differentiation;
or an effect which increases the water retention capacity of intercellular spaces: this effect can be obtained by promoting the synthesis of PG and/or GAG by skin cells, especially, keratinocytes and/or fibroblasts.
PG, formerly called mucopolysaccharides, are complex macromolecules consisting of a central protein, or “carrier protein”, substituted on its serine residues by osidic chains called GAG. These chains consist of a series of hexosamines (glucosamine or galactosarnine) alternating with another sugar (glucuronic or iduronic). In skin they are sulfated in the 2-, 4-, 6-position or on the amine group. (Structure and metabolism of proteoglycans and glycosaminoglycans, J. E. Silbert,
J. Invest. Dermatol
. (1982), 79, 31-37).
Like GAG, PG are secreted in the skin by keratinocytes and fibroblasts and are partly responsible for its hydration.
The organism is permanently subjected to many types of aggression from the external environment.
The skin serves to protect the organism against the external environment. The epidermis is the external barrier of the skin. It consists especially of keratinocytes, which differentiate in the course of their migration from the basal layer of the epidermis to the corneal layer of the epidermis.
One of the most important functions of this barrier, or epidermis, is to prevent water loss from the organism. Another function is to combat the various forms of physical, chemical and microbial aggression from the surrounding medium.
Water loss is largely combated by PG and GAG, which are present in large amounts in the extracellular medium. These molecules participate substantially in the hydration and mineralization (fixation of counterions) of the extracellular matrices, particularly by virtue of their capacity to fix water. They also participate actively in the correct functioning of the epidermal cells.
In particular, these PG and GAG are synthesized by keratinocytes in the epidermis.
Once synthesized by a cell, these PG and GAG remain in the extracellular matrix surrounding this cell and undergo little or no migration.
PG represent about 0.2% of the dry weight of the skin, which is low in comparison e.g. with the amount of collagen, which represents more than 75% of said dry weight (
The collagens: biochemistry and physiopathology
, E. J. Kucharz, published by Springer-Verlag, 1992). This is in no way a reflection of the physiological importance of PG and GAG.
In fact, by dint of their polyanionic osidic structures, these molecules have the characteristic of associating very strongly with counterions (sodium and potassium) and water molecules. They have the capacity to fix water up to 1000 times their volume, thereby forming gels. They therefore behave like natural mineralizing hydrating agents for the epidermis, particularly the epidermal cells and especially the germinal cells, the cellular basal membranes, the skin appendages, particularly the hair follicles, and also the extracellular matrices such as that of the dermo-epidermal junction (DEJ). PG and GAG therefore play a decisive part in the functionality of these cells and of the matrix to which these cells adhere.
The most abundant GAG in the skin are hyaluronic acid (50% of the hyaluronic acid in the organism is in the skin) and dermatan sulfate, while others, like chondroitin 4- and 6-sulfate, heparan sulfate and keratan sulfate, are found in smaller amounts. Hyaluronic acid is without doubt the most widely known skin hydrating agent. It is pointed out that, as distinct from the other GAG, this molecule is neither sulfated nor fixed to a carrier protein.
The epidermis contains chondroitin 4-sulfate and keratan sulfate. The dermo-epidermal junction contains chondroitin 6-sulfate and heparan sulfate, which are very important in the cohesion between dermis and epidermis. Hyaluronic acid is located principally in the basal layer and to a lesser extent in the spinous layer (Age-dependent changes of hyaluronan in human skin, L. J. M. Meyer and R. Stern,
J. Invest. Dermatol
. (1994), 102, 385-389).
It is also known that ageing has important repercussions on the content and distribution of PG and GAG in the skin. The epidermal distribution of hyaluronic acid is seen to fall drastically to the point where it is no longer detected in the senescent epidermis (Age-dependent changes of hyaluronan in human skin, L. J. M. Meyer and R. Stern,
J. Invest. Dermatol
. (1994), 102, 385-389). Likewise, a decrease is noted in the chondroitin 6-sulfate located principally in the dermo-epidermal junction (DEJ) (Patterns of glycosaminoglycan/proteoglycan immuno-staining in human skin during ageing. M. D. Willen,
J. Invest. Dermatol
. (1996), 968-974).
D-xylose is a well-known sugar of the 5-carbon aldose family. For its description, its sources and its main properties, reference may be made to the following publication: Merck Index 20th edition (1996), no. 10220.
Swiss patent CH 368 267 describes compositions with a moisturizing effect which contain a pentose in combination with an amino acid. Xylose is mentioned among the pentoses as a product of hygroscopic character.
Within the framework of the present invention, it has now been discovered, surprisingly, that D-xylose, esters thereof and oligosaccharides containing xylose make it possible substantially and significantly to stimulate the synthesis and secretion of PG and GAG by human keratinocytes.
Thus. by virtue of their stimulating action on the synthesis of PG and GAG by the epidermal keratinocytes, D-xylose, esters thereof and oligosaccharides containing xylose can be used in cosmetic or pharmaceutical compositions, especially dermatological compositions, for topical application. making it possible inter alia to promote hydration of the skin, particularly of the epidermis, but also of tissues with a keratinocyte covering compartment, such as mucous membranes, particularly the lips, and also skin appendages, particularly the hair follicles.
D-xylose, esters thereof and oligosaccharides containing xylose can also be used to prevent or treat the effects of skin ageing, particularly the effects on the epidermis, which is the center of a large decline in PG and GAG content with age, being accompanied in particular by increased dryness of the skin.
D-xylose, esters thereof and oligosaccharides containing xylose can thus be used in any applications where it is desired to improve the synthesis of GAG and PG.
Thus, according to one of its characteristics, the invention relates to the use of a compound selected from the group consisting of D-xylose, esters thereof and oligosaccharides containing D-xylose as a cosmetic agent for stimulating the synthesis and/or secretion of proteoglycans (PG) and/or glycosaminoglycans (GAG) by the keratinocytes, especially the keratinocytes of the epidermis and the tissues with a keratinocyte covering compartment, such as mucous membranes, particularly the lips, and skin appendages, particularly the hair follicles, said agent being incorporated i
Bonte Frederic
Dumas Marc
Krass Frederick
LVMH Recherche
Ostrup Clinton
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