Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-11-29
2003-03-04
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C536S001110, C536S102000, C536S104000, C536S123100, C536S123130
Reexamination Certificate
active
06528069
ABSTRACT:
The present invention relates to a concentrated polyol composition.
The invention also relates to its use for dispersing hydrocolloids such as cellulose and its derivatives, as well as for preparing pharmaceutical or cosmetological products, in particular such as toothpastes.
Toothpastes generally contain an abrasive agent, a wetting agent, water and a gelling agent used to impart a creamy or gel-type consistency and to form a support for all the other ingredients present in the toothpastes, such as flavourings, sweeteners and preserving agents.
The main function of the wetting agent is to maintain a certain level of humidity in the toothpaste when it is exposed to the open air, so as to prevent it from hardening and forming plugs in the orifice of the toothpaste tube.
The wetting agents usually used are glycerol and sorbitol as aqueous solutions, alone or as mixtures. Xylitol is sometimes used, but, since the process for producing it is more complex, it remains a more expensive product.
Consequently, for economic reasons, it is preferred to use sorbitol, which is found on the market in the form of syrups containing 70% solids.
In general, it is used in proportions from about 20 to about 70% of the weight of the toothpaste. It is moreover desirable for the sorbitol to be non-crystallizable, in order to ensure that it is stable before use and that the toothpastes are stable on storage.
As regards the gelling agents, hydrocolloids such as guar gum, guar derivatives, gum arabic, carrageenans, xanthans, methylcellulose, carboxymethylcellulose and hydroxyethylcellulose are generally used. They are used in proportions of from 0.1 to 5% by weight, depending on whether a paste or a gel is desired.
Sodium carboxymethylcellulose, more commonly referred to as CMC, is the gelling agent most commonly used in toothpastes.
During the preparation of toothpastes based on non-crystallizable sorbitol syrup containing 70% solids, the gelling agent is predispersed in the sorbitol syrup. This step is particularly critical since, although hydrophilic, the gelling agent has a tendency to form lumps and to aggregate. In certain cases, water penetrates these lumps very slowly and complete dispersion of the gelling agent is only reached after a considerable amount of time.
Certain manufacturers circumvent this problem by equipping themselves with very high shear mixers, but this equipment is very expensive.
Such is not the case when glycerol is selected as wetting agent, since the gelling agent disperses correctly in glycerol, which is anhydrous and thus does not solubilize it. Once water is added to the formulation, the gelling agent swells and disperses homogeneously to form a thick gel. This is the main advantage of glycerol over sorbitol.
However, many manufacturers are seeking to minimize their use of glycerol on account of its high and fluctuating cost, but also on account of its poor organoleptic performance.
However, as described above, there remains a problem to be solved for toothpaste formulators wishing to favour the use of sorbitol in replacement for glycerol.
One solution has been proposed in patent WO 97/48372 and consists in spraying polyol solutions onto hydrocolloid particles and then in drying the granules thus obtained on a fluidized bed. The polymer particles can then be incorporated into the toothpaste preparation without the formation of lumps. However, the fact remains that this additional step of preparation of the gelling agent further complicates the toothpaste formulation and is economically unacceptable.
Another solution, proposed in U.S. Pat. No. 4,883,537, consists in dispersing hydrocolloid in water, in the presence of an appreciable amount of potassium carbonate. It can easily be deduced that this solution is incompatible with use in toothpaste, on the one hand on account of the high alkalinity of potassium carbonate, and on the other hand on account of the supply of water imposed on the manufacturer.
To overcome the problems of aggregation of the gelling agents, it may be thought that it thus suffices to minimize the water content of the sorbitol syrups, since it is known, on the one hand, that when this water content is too high, lumps appear which are extremely difficult to remove, and, on the other hand, that when the water content of the dispersing medium is sufficiently low, there is no hydration or any anticipated swelling of the gelling agent, and thus no appearance of lumps.
However, the sorbitol syrups which are preferably used as wetting agents can exhibit concentration difficulties above a solids content of about 80%. This is because, when the water contained in such syrups is evaporated off, they become extremely viscous. Under these conditions, it is necessary to make use of sophisticated and thus expensive equipment. Furthermore, these very viscous products have the major drawback of no longer being pumpable, which makes them unsuitable for any industrial use, in particular with regard to the transportation, storage and processing of these syrups.
It has been proposed, in U.S. Pat. Nos. 3,651,936, 4,728,515, 4,671,961 and 4,671,967, to make use, for the preparation of food products such as chewing gums, of concentrated compositions based on coevaporated syrups of starch hydrolysates and of glycerol or of propylene glycol. The reason for this is that glycerol and propylene glycol lower the viscosity of starch hydrolysate syrups and make it easier to evaporate the water which these syrups contain. These concentrated compositions have a relatively low water content, for a glycerol content of at least 25% by weight. However, besides the drawback of its cost, glycerol by nature has an astringent and unpleasant taste which is generally detrimental to the organoleptic qualities of the final product. Similarly, patent WO 95/04107 has proposed dissolving polysaccharides in a mixture of sorbitol and glycerol. However, the presence of sorbitol in large proportions can entail risks of crystallization during storage. Furthermore, since the polysaccharide is present in small proportions (0.1%), this solution cannot be transposed to the preparation of toothpastes which generally contain from 1 to 5% gelling agent.
The aim of the invention is thus to overcome the drawbacks of the prior art and to provide a concentrated polyol composition containing sorbitol, which is better than the compositions which already exist in terms of the various practical requirements, i.e.:
which has a good capacity to disperse the gelling agents without forming lumps, and without necessarily using sophisticated equipment,
which has Theological properties such that it is easy to handle and to transport,
which is easy and economical to prepare,
which can be used in pharmaceutical or cosmetic products, in particular in toothpastes,
which is stable in itself and is capable of imparting sufficient stability on storage to the products into which it is incorporated, in particular with regard to the phenomena of crystallization during storage.
After detailed research, the Applicant has, to its merit, found that this aim can be achieved when the concentrated polyol composition has a selected water content and a specific carbohydrate profile.
Indeed, the Applicant has observed, surprisingly and unexpectedly, that a new phenomenon occurs, at high solids contents, during the dispersion of the gelling agents: in a first stage, the gelling agent disperses easily as expected, but, in a second stage, it absorbs the water present. This is equivalent to a substantial increase in the solids content of the medium, with, consequently, crystallization of the polyols, which is reflected in setting of the entire mixture to a solid.
Thus, unexpectedly, and as will moreover be demonstrated by examples, only a precise water content range in the polyol composition in fact makes it possible to disperse a gelling agent appropriately.
Above 17% water in the said composition, the gelling agent forms lumps in the preparation, and below 10% water, rapid setting of the mixture to a solid is observed after the gelling agent is
Duriez Xavier
Harris Scott L.
Lefevre Philippe
Steffensmeier Gina A.
Page Thurman K.
Pulliam Amy E
Roquette Freres
Sturm & Fix LLP
LandOfFree
Concentrated polyol composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Concentrated polyol composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Concentrated polyol composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3049844