Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
1998-07-06
2003-03-11
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S474000, C424S475000, C424S479000, C424S481000, C424S482000, C424S486000, C424S487000, C424S500000, C424S501000, C424S502000
Reexamination Certificate
active
06531155
ABSTRACT:
The present invention relates to granular materials obtainable by pressing mixtures of at least one pulverulent, rheology-modifying, carboxyl-containing polymer as main component and at least one oil-soluble component.
It is known that weakly crosslinked polycarboxylic acids, which may be hydrophobicized, are widely used in cosmetics, medicine and pharmacy. Such polymers are marketed, for example, under the trade names Carbopol®, Pemulen®, Synthalen®, Rheolate®, Stabylen®, Acrisint®, Junlon®, Hypan® or Hivis®.
These products are finely divided, often easily electrostatically chargeable and very dusty powders. The high proportion of fines in these powders leads to a series of disadvantages in processing, for example ready demixing of the variously sized particles, agglomerate formation, unfavorable flow behavior and material losses resulting from a fine dust. In addition, this fine dust causes health hazards, since an appreciable proportion of this dust has a particle diameter of less than 5 &mgr;m and is therefore able to get into the lungs. The processing of these polymers therefore requires special safety and occupational hygiene measures.
Press agglomeration enables the particle size of polymers to be increased and thus the handleability of the powders to be improved. In Chem. Ing.-Tech. 59 (1987) No. 10: 779-787, Chemie-Technik, Vol. 4, (1975) No. 6: 207-209, and Aufbereitungs-Technik (1980) No. 10: 525-533, the principles of press agglomeration are described for the example of fertilizers. For good press agglomeration, low moisture contents of the material to be pressed are advantageous. For the compaction it is typical that neither moisture nor binder are added during the process. The binder-free press agglomeration allows exclusively binding mechanisms within the polymer to become effective under high pressures.
If the material to be granulated does not have the necessary binding properties under the pressure of the granulating tools, solid or liquid components can be added in exceptional cases to improve the binding.
The press agglomeration of polymers is described, for example, in Eur. J. Pharm. Biopharm 38 (1992), No. 6, 195-198 or in WO 93/23457. These products are suitable for the production of aqueous gels, but are unsuitable for the production of oil-containing systems since they form lumps of gel. In the production of oil-containing systems such as emulsions, it is customary first to disperse the polymers in the oil phase and subsequently to add further components such as water and/or a base. The pressed agglomerates produced according to the prior art do not disintegrate completely in the oil phase under the given conditions, so that the subsequent addition of water and/or a base results in the formation of mixtures containing large, lumpy pieces of gel which undergo strong further swelling: these mixtures are not usable in cosmetics and pharmaceuticals.
It is an object of the present invention to develop low-dust, free-flowing granular materials comprising pulverulent polymer which can be incorporated into oil phases without the disadvantages described and make them available for applications in the cosmetic and pharmaceutical sector.
We have found that this object is achieved by addition of at least one oil-soluble component to the pulverulent polymer before or during press agglomeration to give a granular material which can be dispersed very well in oil and additionally can be handled without complicated safety measures.
The granular materials of the present invention dissolve without formation of lumps of gel and thus form homogeneous emulsions. They are therefore very well suited to the production of pharmaceutical and in particular cosmetic preparations based on oil-in-water emulsions. The present invention accordingly provides for the use of the above-described granular materials and corresponding preparations.
Granulatable carboxyl-containing polymers are commercially available or described in the literature. For example, a listing of products commercially used in cosmetics may be found in D. Laba (Editor), Rheological Properties of Cosmetics and Toiletries, M. Dekker Inc., 1993, pages 55 to 152. Preference is given to using polycarboxylic acids and polycarboxylic acid copolymers.
These weakly crosslinked polycarboxylic acids, which may be hydrophobicized, are preferably prepared by precipitation polymerization in organic media. DE-A-43 25 158 describes the precipitation polymerization methods. Examples of such polymers are given in the patents EP-A-128 237, EP-A-584 771, EP-A-371 421, EP-A-470 098, U.S. Pat. Nos. 4,066,583, 3,915,921, 2,798,053, 5,034,486, 5,034,488, WO 92/01724, EP-A-238 404, EP-A-436 960, DE-A-4 213 283, DE-A-4 213 971 or DE-A-4 325 158.
According to the present invention, it is particularly advantageous to granulate pulverulent, rheology-modifying, carboxyl-containing polymers obtainable by free-radical-initiated copolymerization of monomer mixtures comprising
a) 40-99.99% by weight of a monoethylenically unsaturated C
3
-C
6
-monocarboxylic acid, a monoethylenically unsaturated C
4
-C
8
-dicarboxylic acid or their anhydrides or salts or mixtures of the specified carboxylic acids, their anhydrides and/or salts,
b) 0.01-10% by weight of a crosslinker,
c) 0-20% by weight of an ester of a monoethylenically unsaturated C
3
-C
8
-monocarboxylic or dicarboxylic acid with at least one linear or branched C
1
-C
40
-alcohol, and
d) 0 to 60% by weight of other monomers copolymerizable with the monomers (a), (b) and (c),
where the various monomers add up 100%.
The monomers a) are monoethylenically unsaturated C
3
-C
8
-monocarboxylic and dicarboxylic acids, their anhydrides, their salts or mixtures of the specified carboxylic acids, anhydrides and salts. Suitable carboxylic acids are, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid or crotonic acid. Suitable anhydrides are, for example, acrylic anhydride, methacrylic anhydride or maleic anhydride. Among the monomers of the group a) preference is given to using acrylic acid, methacrylic acid, maleic acid and/or maleic anhydride. The monomers can be present in the monomer mixtures to be polymerized in amounts of, for example, 40-99.99% by weight. If the monomer a) is fumaric acid, maleic acid or maleic anhydride, it is particularly preferably used in amounts of 50-80%, very particularly preferably in amounts of 50-64.8% by weight. If the monomer a) is acrylic or methacrylic acid, it is particularly preferably used in amounts of 70-99.93%, very particularly preferably in amounts of 85-99.8% by weight.
The monomers a) can also be partly incorporated in the form of their salts. This can be achieved, for example, by addition of at least one base before, during or after the polymerization. If the polymers are used in the form of their salts, up to 90 mol %, preferably up to 40 mol %, of the carboxyl functions have been converted. However, in the particularly preferred case, over 90 mol % of the carboxyl groups are present in free form or as anhydride.
If the monomers are present in the form their salts, preference is given to the alkaline earth metal, alkali metal or ammonium salts or the salts of organic amines; particularly preference is given to the alkali metal or ammonium salts.
Crosslinkers used for this purpose are generally known compounds, in particular monomers containing at least 2 monoethylenically unsaturated groups in the molecule.
Suitable crosslinkers of this type are, for example, acrylic esters, methacrylic esters, allyl ethers or vinyl ethers of at least dihydric alcohols. The OH groups of the parent alcohols can here be completely or partially etherified or esterified. Examples of dihydric alcohols which can be used are 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, but-2-ene-1,4-diol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,10-decanediol, 1,2-dodecanediol, 1,12-dodecanediol, neopentyl glycol, 3-methylpentane-1,5-diol, 2,5-dimethyl-1,3-hexanediol, 2
Börs Thekla
Heinz Robert
Schade Christian
Wekel Hans-Ulrich
BASF - Aktiengesellschaft
Channavajjala Lakshmi
Keil & Weinkauf
Page Thurman K.
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