Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2001-03-19
2003-06-03
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S400000, C424S401000, C424S502000
Reexamination Certificate
active
06572892
ABSTRACT:
This invention concerns a new type of bio-compatible pearl capable of containing various substances, biologically active constituents, cosmetic or pharmaceutical constituents, pigments or load products.
The use of active principles, or any compound or substance, for topical applications with a dermo-pharmaceutical or cosmetic purpose, requires incorporation into a support, referred to as a “base” for cosmetic applications and a “galenic support” for pharmaceutical applications.
This support has numerous functions:
it must allow practical application at the administration point. In the case of local application with a cosmetic or dermo-pharmaceutical purpose, a fluid with an adapted rheologic behaviour is the form of support the most often chosen.
it must allow the dilution of the active principle or the active compounds to obtain the desired concentration compatible with the effect sought.
it must provide, in the case of cosmetic products, a feeling to the touch as agreeable as possible, and, in this case, the sensorial properties of the support are of primary importance.
The majority of cosmetic or dermo-pharmaceutical bases for topical applications are aqueous compounds, for example gels, lotions and emulsions. These cosmetic products are makeup removers, toning products, slimming gels, after-sun creams or lotions, capillary products, personal care products, tooth pastes and certain makeup products. Dermo-pharmaceutical compounds also use the such supporting bases.
These aqueous bases are today very widely used due to their high water content that gives, on application, a sensation of coolness on the skin and mucous. They leave no residue, do not shine and do not give a greasy aspect or feeling to the skin.
However, these aqueous bases, in particular, those in continuous aqueous phase, present a certain number of inconveniences recalled in patent FR 2 660554. Briefly, we note the drying effect of these bases on the skin, which is badly tolerated with dry or normal skin. The capacity of gels and emulsions to incorporate certain ingredients, such as essential oils or perfumes, without being destabilised, remains weak.
The bases of the emulsion type, containing a greasy phase, present a very creamy consistency. They are very much sought after since they are easily applied with the fingers from ajar or tube container (Patent FR 2734714). The great stability of these emulsions is due to the presence of waxes in the greasy phase whose melting point is generally higher than 80° C. Their preparation, at a temperature exceeding the wax melting point, prevents the use of thermo-sensitive active principles.
In addition to the drying effect observed, the aqueous phase is very favourable to the development of micro-organisms (Pharmacie galénic—Bonnes pratiques de fabrication des medicaments—A. Le Hir, Ed. Masson, page 88). Agents that limit the development of a wide spectrum of microbes must therefore be incorporated into these preparations. These agents, called preservatives, can be toxic for the skin of some people. Thus the use of certain preservatives is today highly regulated or even prohibited for some, for example diisobutyl-phenoxy-ethoxy-ethyl-dimethyl-benzylammonium, (Legislation et réglementations—Produits cosmétiques et produits d'hygiène corporelle—1997—page 229).
Finally, the water present in these cosmetic and dermo-cosmetic bases constitutes a very favourable environment for radical reactions and, in particular, oxidation reactions. Thus, the incorporation of molecules very sensitive to oxidative stress, such as vitamin C, certain fatty acids or certain polyunsaturated molecules, is very difficult due to low stability in time.
In the case of bases associating an aqueous phase and a lipidic phase, the essential presence of amphipilic molecules with surface-active powers allows stable dispersion and the blending of the two phases. These molecules may be rather aggressive for the skin (Les molecules de la beauté. De l'hygiène et de la protection pages 33-38, les tensioactifs, Pierre le Perchec, Ed. Nathan). We are therefore seeking to obtain anhydrous bases in which the active principles can be incorporated at temperatures less than 80° C. and whose texture is sufficiently creamy to allow satisfactory spreading with the fingers.
Anhydrous formulations destined for cosmetic and dermo-pharmaceutical applications have been known for a long time. The oldest are constituted from animal, vegetable, or mineral oils, or a blend of these. These oily forms are no longer used due to their greasy texture. Makeup bases in greasy phase are used above all because they adhere to the epidermis, provide protection and form a water-impermeable film. Anhydrous makeup products often come in a solid compact form, for example, lipstick, or in cream form (Peau-Soins cosmétioques et Préparations dermo-pharmaceutiques—R. Raoult, Ed. Porphyre page 106).
These bases, whilst interesting, are, nonetheless, very greasy and thick. On the one hand, their stability implies the presence of waxes whose melting temperatures, generally higher than 80° C., prevent the use of thermo-sensitive active principles.
An improvement is proposed in the French patent FR 2 734714, with the use in the base of an association of, in particular, organo-modified clay, polymer particles, pyrogenic silica dispersed in a greasy phase without the use of wax. This base, in anhydrous gel form, though still greasy is sufficiently creamy to be spread with the fingers. It can incorporate thermo-sensitive molecules. However, the clays used are modified by greasy quaternary ammonium salts that can be irritating for the skin. Finally, the greasy phase comprises oils of an amphiphilic nature, giving a shiny aspect to the skin.
After different studies, we have noted that the inconveniences of such previously used bases, that is to say:
the drying effect, the presence of surface-active agents and antioxidants, the impossibility to use molecules sensitive to the oxidative stress in the case of aqueous bases,
the greasy effect, the impossibility of using thermo-sensitive molecules, the shiny aspect and the difficulty of spreading for the anhydrous bases,
could be solved by the use of pearls with a strictly anhydrous base and completely lacking surface active-agents, thus defining the invention.
Surprisingly, we have discovered that the association of oils, mineral waxes, animal or vegetable waxes, talc and silica, give a solid base, stable in time, able to contain active principles, offering a non-greasy, melting, film-forming, easy-to-spread texture without residues nor a shiny aspect.
However this base is not creamy enough to be easily taken with the fingers from ajar or tube container.
We have discovered that the particles prepared from this base, used alone, adhere sufficiently to the epidermis to be able to be taken easily with the finger and to be applied whilst retaining the properties of the base. We will give the name pearls to the particles resulting from the shaping of these bases. The base appears to be in a dispersed state, allowing topical cosmetic and dermo-pharmaceutical applications.
One of the aspects of this invention is that the base comprises at least one hydrophobic wax, a non amphiphilic oil and talc. The final melting temperature must be between 15° C. and 70° C., and preferably between 20° C. and 45° C.
The invention bases are mainly constituted from wax or blends of mineral waxes, non-greasy, non-amphiphilic mineral oils, talc and silica. They can contain, in addition, oily, paste or solid additives and liposoluble or hydrosoluble active ingredients.
The base generally contains from 0.1% to 40% of paraffin wax or a blend of paraffin wax and waxes chosen preferably from among:
Carnauba wax
Candelilla wax
Alfa wax
ozocerite
vegetable waxes such as olive wax, rice wax, hydrogenised jojoba wax or absolute flower waxes.
bees' waxes or modified bees' waxes.
It is possible to use other wax matrices, but the blend obtained must be characterised by a melting point of less than 90° C., by the absence of surfa
Ioulalen Karim
Raynal Rosanne
Browdy and Neimark P.L.LC.
Joynes Robert M.
Page Thurman K.
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