Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Carbohydrate doai
Reexamination Certificate
1999-07-09
2001-03-06
Peselev, Elli (Department: 1623)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Carbohydrate doai
C514S023000, C514S054000, C536S001110, C536S103000, C536S123130, C536S124000
Reexamination Certificate
active
06197757
ABSTRACT:
FIELD OF INVENTION
The present invention relates essentially to particles, especially microparticles or nanoparticles, of crosslinked monosaccharides and oligosaccharides, to processes for their preparation and to cosmetic, pharmaceutical or food compositions in which they are present. These particles are advantageously of small dimensions. In addition, these particles are advantageously used for the incorporation or encapsulation of various hydrophilic or lipophilic substances and particularly substances which can be used in the pharmaceutical, cosmetic and food sectors.
Within the framework of the present description and the claims, the words “particle(s) of small dimensions” denote both microparticles and nanoparticles and the words “microparticles” or “nanoparticles” relate both to microspheres or nanospheres and to microcapsules or nanocapsules.
Furthermore, the words “microspheres” or “nanospheres” refer to particles which have an essentially uniform structure throughout the whole of their bulk, while the words “microcapsules” or “nanocapsules” refer to particles which have a crosslinked wall surrounding an internal core or space filled with a solid, gelled, liquid or gaseous medium.
STATE OF THE ART
The encapsulation of active substances in particles offers valuable advantages such as, for example, protection of the encapsulated substance or its slow release at the site of use for a prolonged effect.
If the particles are intended for use in the cosmetic, pharmaceutical or food sectors, they must consist of biocompatible materials such as proteins and polysaccharides.
The preparation of microcapsules from polysaccharides, i.e. high-molecular carbohydrates, has been widely described in the prior art literature (cf., for example, P. B. Deasy: Microencapsulation and related processes, Drugs and the Pharmaceutical Sciences, vol. 20, 1984, Marcel Dekker).
In particular, these compounds can be used by themselves in microencapsulation processes based on simple coacervation, or associated with polycationic polymers in processes based on the formation of polyelectrolyte complexes.
Microcapsules have also been prepared by the interfacial crosslinking of polysaccharides by means of polyfunctional isocyanates, as described for example in document FR-A-2 275 250, which relates to microcapsules prepared from hydroxypropyl cellulose, or in document U.S. Pat. No. 4,138,362, which applies to natural gums or chitosan.
Furthermore, microcapsules with a wall formed of co-crosslinked glycosaminoglycans and collagen are described in document FR-A-2 642 329, which relates to the application of interfacial crosslinking by means of diacid chlorides to mixtures of glycosaminoglycans and collagen.
Interfacial crosslinking by means of diacid chlorides in emulsion systems has also been applied to the preparation of particles from polysaccharides in document EP-0 630 287 B1 equivalent to U.S. Pat. No. 5,562,924, the reaction pH values used not exceeding 10.
In these various processes for the preparation of microcapsules, the carbohydrates used are polysaccharides, i.e. molecules with high molecular weights above 5000 daltons, which consist of an association of a large number of oside units. In fact, it is well known that macromolecules like proteins and poly-saccharides have special adsorption properties at interfaces; cf., for example, pages 317 to 335 of the following work: “Functional properties of food macromolecules”, edited by Mitchell J. R. and Ledward D. A., Elsevier, London, 1986. These adsorption phenomena at interfaces, which result in the formation of an interfacial film, are a particularly favorable factor in the preparation of particles by the interfacial crosslinking of biopolymers such as polysaccharides.
As regards carbohydrates with molecular weights below 5000 daltons, the prior art literature contains processes for the preparation of polymer beads from cyclodextrins, which are cyclic oligosaccharides having a hydrophobic cavity capable of trapping various molecules of compatible geometry. The most widely employed crosslinking agent is epichlorohydrin, as for example in the article by Wiedenhof N. et al. (Die Stärke, 1969, 21, 119-123).
As far as the use of acid dichlorides is concerned, document U.S. Pat. No. 3,472,835 describes the preparation of cyclodextrin resins by crosslinking in a homogeneous medium (DMF or DMSO). However, the preparative conditions are drastic, the reaction taking place at 100° C. for a prolonged period of time (6 h). Moreover, the substances to be trapped do not easily diffuse into these compact beads. Proposals have been made to improve the porosity of the polymers, either by generating a release of CO
2
in situ (in document U.S. Pat. No. 4,958,015) or by carrying out the crosslinking on the surface of a porous mineral oxide (U.S. Pat. No. 4,902,788). Document U.S. Pat. No. 4,902,788 indicates (p. 3, column 3, lines 54-55) that the principal disadvantage of aromatic acid dichlorides is that they give relatively low yields of resin.
Thus the prior art neither describes nor suggests the preparation of particles by the interfacial crosslinking of monosaccharides or oligosaccharides, such as cyclodextrins, by means of acid dichlorides in emulsion systems.
OBJECTS OF THE INVENTION
One main object of the invention is to solve a new technical problem consisting in the provision of biocompatible and biodegradable, stable particles which optionally incorporate various hydrophilic or lipophilic substances and can be used in the pharmaceutical, cosmetic and food sectors.
A further main object of the invention is to solve a new technical problem consisting in the provision of biocompatible and biodegradable particles by a particularly simple manufacturing method affording particles of constant quality, preferably from substances of perfectly defined chemical composition, which also are advantageously capable of being dissolved, particularly in an aqueous phase at room temperature.
One main object of the present invention is to solve a new technical problem consisting in the provision of novel biocompatible and biodegradable particles of small dimensions from monosaccharides and oligosaccharides.
A further object of the present invention is to solve a new technical problem consisting in the provision of a solution for the preparation of stable particles of small dimensions from monosaccharides and oligosaccharides, while at the same time optionally allowing the encapsulation of one or more active substances in the form of a solution, suspension or emulsion.
A further object of the present invention is to solve a new technical problem consisting in the provision of a solution for the preparation, from cyclodextrins, particularly &bgr;-cyclodextrins, of novel biocompatible and biodegradable, insoluble particles of small dimensions which can easily be isolated from a liquid medium and have retained the specific trapping capacity of these cyclodextrins.
A further object of the present invention is to solve a new technical problem consisting in the provision of a solution for the preparation, from cyclodextrins, particularly &bgr;-cyclodextrins, of novel biocompatible and biodegradable, porous, insoluble particles of small dimensions which can easily be loaded with various active molecules and then incorporated into larger particles, which are also biocompatible and biodegradable, so as to allow a slower and sustained release of the active molecule by diffusion through the material of said larger particle.
A further object of the present invention is to solve a novel technical problem consisting in the provision of a solution for the preparation of a product from dihydroxyacetone (DHA) which, when incorporated into a composition, does not impair its stability, particularly its color stability, and which, when applied to the skin, will release the DHA, the latter being capable of combining with the amino acids in the skin to produce a pigmentation.
A further object of the present invention is to prevent any degradation of a composition containing DHA, in particular any m
Andry Marie-Christine
Buffevant Chantal
Edwards Florence
Levy Marie-Christine
Pariot Nadine
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