WO1996018378A2

WO1996018378A2 - Single phase aerosol antiperspirant composition

Info

Publication number: WO1996018378A2
Application number: PCT/US1995/016286
Authority: WO
Inventors: Fred Presant; Agnes M. Terraforte
Original assignee: Fred Presant; Terraforte Agnes M
Priority date: 1994-12-14
Filing date: 1995-12-14
Publication date: 1996-06-20
Also published as: AU4961896A; WO1996018378A3

Abstract

Disclosed are aerosol compositions providing a single phase solution of an aluminum antiperspirant and polyol. The polyol solution is combined with a propellant and, optionally, polyol solubilizing carrier substances, to form a single phase composition for dispensing from a pressurized container. Propellants include dimethyl ether, while polyol solubilizing carriers, in which the polyol is soluble, include alcohol and water. The polyol is present at a ratio of at least 0.6 by weight polyol based on active ingredient. The composition is formulated to provide on the skin or other surface to which the composition is applied an aluminum antiperspirant active ingredient soluble in polyol after the propellant and/or solubilizing carrier is vaporized. The composition may be anhydrous or not. Very high concentrations of active ingredient are obtained at low levels of volatile organic compounds.

Description

Single phase aerosol antiperspirant composition

BACKGROUND OF THE INVENTION

The present invention relates to single phase liquid compositions to be dispensed by an aerosol dispensing system. The invention relates in particular to the field of single phase aerosol compositions which have a high concentration of active aluminum antiperspirant ingredient (insoluble in past aerosol formulations) , a polyol, a propellant or a propellant and a polyol solubilizing carrier; said composition having improved polyol and active ingredient solvent properties compared to prior art formulations.

Aerosol products offer advantages over products dispensed by pumps or other systems, including, for example, that ambient atmosphere is excluded from the aerosol container with the consequence that the product is not exposed to deteriorating or oxidizing effects of air. Moreover, the product maintains its sterility. Further, consumers prefer aerosols for their convenience, ease of use and cleanliness. Generally, the characteristics of the spray dispensed from aerosol systems are superior to those of other packaging systems.

Aerosol formulations having a solid dispersed in the formulation to be dispensed, rather than dissolved in the composition, present the disadvantages of orifice clogging and disruption of the aerosol valve sealing surface with the obvious negative consequences. In the past, the difficulty has been to formulate a composition wherein all the components are mutually miscible, i.e., a single phase composition. Moreover, the single phase composition must possess the desired spray characteristics and product performance. Consistent with the desire to improve the environmental impact of aerosol products, formulations are now being designed with a lowering of the volatile organic compounds (VOC) ; said lowering of VOC's in the composition often resulting in an increase in the difficulty of obtaining a single phase composition. Moreover, as the antiperspirant market has moved in the direction of higher concentrations of the active ingredient, the problem of solubilizing the several components has become more acute.

DESCRIPTION OF THE PRIOR ART

Some patents, such as U.S. Patent No. 3,873,686; U.S. Patent No. 3,876,758; U.S. Patent No. 3,359,169; U.S. Patent No. 3,420,932; U.S. Patent No. 3,405,153; and U.S. Patent No. 3,555,146 describe anhydrous antiperspirant active ingredients which are complexes of an aluminum and/or zirconium halide/hydroxide complexed with a small amount of a polyol such as propylene glycol.

A solution of 3 parts antiperspirant mixed with 7 parts propylene glycol is available for use in solid deodorants, but has not been used or suggested for use in aerosol formulations.

Accordingly, it is a principal object of the present invention to provide a single phase composition useful in an aerosol dispensing system having a relatively high percentage of aluminum antiperspirant active ingredient with a relatively low percentage of volatile organics.

A further object of the invention is to provide an aerosol dispensing composition in which the aluminum antiperspirant active ingredient and other components are soluble in the propellant mixture and remain soluble when dispensed onto the target area for a period sufficient to efficaciously effect its antiperspirant action.

SUMMARY OF THE INVENTION

The foregoing objectives are achieved by forming a single phase composition comprising:

(a) an aluminum antiperspirant active component, e.g., an aluminum chlorhydrol antiperspirant in an amount of at least 6% by weight of the total composition;

(b) a polyol component present in an amount of at least 14% by weight of the total composition; and

(c) a polyol solubilizing propellant and, optionally, a polyol solubilizing carrier, wherein i. the propellant component may be selected from any known aerosol propellants, in which the

(a) and (b) components above are soluble, such as lower alkyl ethers, non-chlorinated fluorocarbonβ, such as difluoroethane,

1, 1, 1,2-tetrafluoroethane, low boiling hydrocarbons mixed with the previous propellants and mixtures thereof; and ii. the polyol solubilizing carrier may be compounds such as lower alkyl alcohols, esters, ethers, glycols and ketones; lower polyalkylene glycols; water; and mixtures thereof.

When alcohol, water or mixtures thereof are carriers, a propellant such as a lower alkyl ether may be preferably admixed therewith.

The aerosol dispensing composition of this invention is further characterized by having a high concentration of aluminum antiperspirant compound solubilized in the polyol and carrier when the propellant has volatilized. Certain of the compositions of this invention are still further characterized by having a low VOC content. Any polyol solubilizing carrier substance can be substituted for all or part of the propellant when using a barrier pack aerosol system.

In general, the polyol, the polyol solubilizing carrier, with or without propellant may be used to form single phase compositions with aluminum antiperspirant compounds that will form a single phase solution with the polyol and which aluminum antiperspirant compounds have limited or reduced solubility in aerosol compositions absent the polyol.

DETAILED DESCRIPTION OF THE INVENTION

One component of the composition of the present invention is the aluminum antiperspirant compound, the active component, which is solubilized or complexed with a polyol and subsequently formulated to form a single phase composition with a suitable propellant, and optionally, a polyol solubilizing carrier. Hereafter, the invention will be discussed or illustrated utilizing an antiperspirant as the active ingredient, it being understood that other active components which are capable of complexing with a polyol may be substituted.

Examples of suitable antiperspirant compounds and mixtures thereof are known to those of ordinary skill in this art and include simple halides of aluminum. For further examples of antiperspirant active ingredients useful in the present invention, reference may be had to the disclosures of U.S. Patent No. 3,904,741; and U.S. Patent Nos. 3,288,681, 3,359,169, 3,420,932 and 3,873,686. Exemplary of such antiperspirant compounds are chlorhydrol's corresponding to the formula Al_(0H)_yCl_3x._y where x is 2-5 and y is 2-14, such as A1₂(0H)₂C1₄, Al₂(OH)₄Cl₂,Al₄(OH)_gCl₃,Al₃(OH)₆Cl₃, and A1₂(0H)₅C1.

The aluminum antiperspirant component is complexed in polyol to form a single phase, which single phase is soluble in the propellant or propellant and carrier. Preferred aluminum antiperspirant active compounds are those sold as Chlorhydrol or as "Reach," sold by Reheis Chemical Company. A preferred example is the antiperspirant concentrate known as "Reach 301 PG, " sold by Reheis Chemical Company for use in solid antiperspirants. The concentrate is a substantially anhydrous concentrate of about 30% antiperspirant active ingredient complexed with 70% propylene glycol. An aqueous formulation "Reach 301 AQ" of 50% antiperspirant active ingredient in 50% water is also useful for aqueous systems. Hereafter the combination of antiperspirant compound and polyol will be referred to as the "active ingredient."

The antiperspirant component (aluminum compound) is present in the composition of this invention in an amount of at least 6% by weight of the total composition and preferably in an amount of at least 15% by weight of the total composition. It will be noted, of course, that the amount of active ingredient that may be present is influenced by the amount desired to be applied by the user upon application from an aerosol package and is also a function of the solubility of the overall composition both within the aerosol container and upon the target area.

Another component of the composition of the present invention is the polyol component. Examples of useful polyols are any polyols easily soluble in the propellants or propellants and carriers selected and which solubilize substantial amounts of the antiperspirant or other active ingredient. Preferred polyols include lower alkyl polyols having two or three hydroxyl groups, especially propylene glycols, such as propylene glycol, dipropylene glycol and mixtures thereof.

In the compositions of this invention the polyol component is present in an amount of at least 14% of the total composition, most preferably in an amount of at least 35% of the total composition. The polyol component assists in solubilizing the antiperspirant active component in the total composition and in the balance of the composition after dispensing and the propellant has volatilized. The polyol component of the composition of this invention may be present as a part of the carrier for the aluminum active component/polyol complex, such as, for example, the Reheis products referred to above, or as separately added polyol.

The solubility of the aluminum antiperspirant component in the polyol is retained following application of the product to the skin, thereby providing the aluminum antiperspirant active component in a form which is effective upon application, without requiring resolubilization of the aluminum antiperspirant active component on the skin. Also, application of a soluble aluminum antiperspirant does not lead to formation of an unsightly deposit of dried or undissolved active antiperspirant ingredient. Furthermore, the polyol component assists in providing an emollient, soothing treatment to the skin, and thus it is capable of easing the astringent sensation which can be experienced upon contact of the antiperspirant active ingredient with the skin, without lessening the desired antiperspirant effectiveness of the active ingredient. Finally, the polyol provides a substance which allows much larger amounts of active ingredient to be dissolved in the total composition. In addition, the polyol component has limited volatility and does not contribute to volatile organic discharge to the environment. Preferably, in the compositions of the present invention, the weight ratio of the polyol to the antiperspirant is at least 0.6/1, often 1/1 and for anhydrous mixtures 7/3 or more. For conventional aerosol packages the aluminum antiperspirant active ingredient and polyol is dissolved in a propellant and optionally, a polyol solubilizing carrier or dissolved in a polyol solubilizing carrier for use in a barrier-type aerosol package. In both cases the propellant and carrier are substances in which the polyol and the antiperspirant are soluble, at least to the level of concentration employed in the composition. Any known aerosol propellant may be employed either in combination with the polyol and antiperspirant or in a barrier package. Propellants particularly preferred for use with the polyol and antiperspirant are ethers, such as dimethyl ether and non- chlorinated fluorocarbons, such as 1,1- difluorethane and 1,1,1,2 - tetrafluoroethane and lower alkanes if mixed with the previously mentioned propellants. Suitable carriers in which the aluminum antiperspirant/polyol complex is soluble are lower alkyl alcohols, ethers, ketones, esters and glycols; water; lower polyalkylene glycols, and mixtures thereof.

The propellant-polyol solubilizing carrier may comprise up to 80 wt.%, usually 15 - 65%, preferably 15 - 50% and most preferably 15 - 40% of the total composition. Compositions are easily formulated to provide concentration levels (10 - 30%) of aluminum antiperspirant. These compositions can further be formulated to maintain the volatile organic content below 50%, preferably below 40%. All of the compositions are single phase liquids which remain a single phase composition on dispensing and after the propellant volatilizes on application to the target or skin. The propellant is used in an amount effective to discharge the composition and is present from 15 wt.% to 45 wt.%, more preferably, from 20 wt.% to 40 wt.% of the total composition. The polyol solubilizing carrier in which the polyol is soluble is present from 0 - 50 wt.%, and most preferably 5 wt.% - 40 wt.% of the total composition. As noted previously, the compositions of the present invention may contain an alcohol carrier, which contains 2 to 6 carbon atoms. The alcohol component (preferably ethanol or isopropanol) assists in the solubilization of the aluminum antiperspirant/polyol composite and the retention of solubility upon application of the composition to the skin. The alcohol is desirably relatively volatile, so that following application of an antiperspirant composition to the skin, for example, the alcohol evaporates leaving behind the aluminum antiperspirant active component solubilized in the polyol component. The alcohol also lowers the greasy or oily nature of the polyol. The alcohol component, if present, generally is uβed in amounts up to 50 wt.%, preferably, about 5 wt.% to about 40 wt.% of the composition, and, more preferably, about 10 wt.% to about 35 wt.% of the composition.

The present compositions may also contain water as a polyol solubilizing carrier, usually to replace some or all of the alcohol or other carriers. Water can be used in amounts up to 50%, preferably 5 - 40% and, most preferably, 5 - 25% as a carrier to reduce the volatile organic compounds present in the composition. When alcohol, water, or a mixture thereof is employed, at least one propellant can be employed in which carrier, polyol and active ingredient are all soluble. Often this propellant is dimethyl ether, which forms a single phase system with polyols, water, alcohol and antiperspirants.

Preferred propellants include lower alkyl ethers such as dimethyl ether, and non-chlorinated fluorocarbons, especially those with 2 to 3 carbon atoms such as 1,1,1,2- tetrafluoroethane ("134A") and 1,1-difluoroethane ("152A") . Other exemplary propellants include low boiling hydrocarbons containing 3 to 4 carbon atoms such as propane, isobutane, and n-butane when mixed with the previous propellants.

Preferred single-phase compositions include dimethyl ether as propellant and alcohol and water alone or combined with each other as a polyol solubilizing carrier.

Preferred single-phase compositions include aluminum antiperspirant/polyol solution, alcohol or water or mixtures thereof with an effective amount of propellant, such as dimethyl ether in which the other components are soluble. The total content of volatile organics such as alcohol, esters, ketones, ethers and hydrocarbons in the formulation should not exceed about 80 wt.%, often less than 60%, generally less than 50 wt.%, preferably 40% or less. While propellant and solubilizing carrier components may total up to 80% by weight, usually from 15 - 45wt.%, propellant combined with 5-50% solubilizing carriers such as alcohol, water or mixtures thereof are used while maintaining the VOC content at 60% or less.

Particularly preferred formulations are substantially anhydrous, single phase combinations of aluminum antiperspirant active ingredient(s) , polyol, usually alcohol and propellant wherein the total VOC content of the mixture is 60 wt.% or less, preferably less than 50 wt.%, and often less than 40 wt.%. These formulations may be compounded at a polyol to antiperspirant ratio of 7/3 or more so that on delivery to the surface or skin, the antiperspirant remains in a single phase solution in the polyol. Where alcohol is present, propellant for solubilizing polyol and alcohol such as dimethyl ether or equivalent may be present. Avoiding the presence of water affords numerous advantages, including often greater control of the solubility of the antiperspirant active component. In addition, avoiding the presence of water greatly reduces the likelihood that the composition may prove to be corrosive to the aerosol container. This, in turn, lessens the need for special linings or coatings with which to protect the container materials from the risk of corrosion. In such compositions, alcohol is often added to enhance solubility.

Alternatively, a unique advantage of the present invention is that water may be used as a carrier to further reduce the volatile organic compounds of the composition to below 60 wt.%, often 50 wt.%, and preferably below 40 wt.%. Water may be used alone or combined with alcohol and/or other solubilizing carriers. A propellant, such as dimethyl ether, is employed to give a clear one phase solution of aluminum antiperspirant, polyol, carrier and propellant.

Propellants that do not solubilize the polyol component may be used provided other polyol solubilizing carrier or propellant is present which solubilizes the aluminum antiperspirant/polyol and forms a single phase solution of all ingredients. Compressed gases such as air, nitrogen, carbon dioxide, nitrous oxide and the like can be mixed with the other ingredients or may be used in barrier packs, and may include other conventional propellants.

Advantageously, the composition of the present invention and the amounts thereof are selected so that when they are under pressure in an aerosol container, there is formed under the gaseous propellant head space a single phase liquid product. Preferably, this liquid is clear, i.e., translucent or even transparent. The composition should exhibit the desired homogeneity both within the pressurized aerosol dispenser and upon the target area after dispensing from the container. Selection of the identities and amounts of components, with the guidance of the description provided herein by the applicant, so as to provide the desired single phase, is well within the capabilities of routine experimentation familiar to those of ordinary skill in this art.

The fact that the liquid composition is homogeneous affords many advantages. One is that the active ingredient is applied to the target area in an amount that varies very little, if at all, from use to use. Also, there is no need to shake the container to redissolve or dispense the antiperspirant within the container before use. Failure to adequately shake dispersions of solids will vary the amount of active ingredient delivered to the skin.

The dispensing system of the present invention can be produced using techniques conventionally employed for manufacturing aerosol dispensing systems. A solution is prepared of the aluminum antiperspirant active ingredient, the polyol component, fragrance and polyol solubilizing carrier, if any. An amount of this solution is charged to the container, using conventional means. Then, the propellant of choice is fed into the container. The propellant can be fed using conventional filling techniques employed in this industry for charging propellant to an aerosol container. Of course, the propellant chosen should be a good solvent for the entire mixture, not interact with the active ingredient or any other components of the composition, as by undergoing chemical reaction or by forming an indispersible gel or other byproduct. Determining propellants to satisfy these criteria is a straight-forward matter. The preferred propellant is dimethyl ether, which forms highly concentrated solutions of antiperspirant and polyol with or without alcohol and/or water and/or other polyol solubilizing carriers. The present invention will be illustrated in the following examples and tables. These are provided for purposes of illustration only and are not intended to limit the scope of the invention in any manner. E MELEJ.

Antiperspirant compositions were prepared by mixing together the active antiperspirant ingredient f Reach 301 PG", sold by Reheis Chemical Company as a complex of antiperspirant active ingredient in propylene glycol), added glycol component, if any, and optionally a carrier component, such as alcohol; charging the resulting intermediate mixture to a clear bottle and then charging propellant through the aerosol valve attached to the bottle. The amounts of ingredients are weighed to give the intermediate mixture and the amount of propellant determined by weighting the bottle after charging with propellant. The components and the amounts used in each test are shown in the following Table 1. The mixture in the bottle was then observed to determine whether the mixture remained a clear, one-phase homogeneous solution or whether it separated into two phases, whether it contained precipitate or gels, and the observations are also set forth in Table 1. The formulas in Example 1 are substantially anhydrous in that they do not contain intentionally added water.

Example 2

The procedure followed in Example 1 was employed to prepare concentrated chlorhydrol substantially anhydrous containing compositions using "Reach 301 PG". The products were observed to determine if they remained as clear, one phase, homogeneous solutions or whether they separated into two phases or experienced precipitation and the observations are set forth in Table 2.

Table 2** Anhydrous Antiperspirant Products

* Calculated on the use of 30% active ingredient in propylene glycol. The above is based on the final product including propellant.

^••(All Amounts in Weight %)

(Table2.doc) — 1 o—

Example 3

The procedure followed in Example 1 and 2 was employed to prepare water containing compositions using "Reach 301 AQ" and "Reach 301 PG". The products were observed to determined if they remained as clear one phase homogeneous solutions or whether they separated into two phases or expeπenced precipitation. The proportions employed and sample observations are set forth in Table 3.

WO 96/18378

Table 3"» Hydrous Antiperspirant Products

Test No.

Antiperspirant • 100% 20 20 15 15 20 21 Active Ingredient*

Propylene glycol 15*^* 15 40 10 20 14

Ethanol (100%) 15 15 — 30 10 20

Water 20 20 15 15 20 15

Propellant-Dimethyl 30 30 30 30 30 30 ether

Solubility-immediately clear clear ear clear clear clear

Solubility - 2 weeks • room temperature clear clear dear ppt. dear dear

VOC% 45 45 30 60 40 50

Ratio polyol active 0.75/1 0.75/1 2.67/1 .67/1 1/1 .67/1

^• Calculated on the basis of 50% active ingredient in water using Reach 301 AQ except for example 6, where a combination of Reach 301 AQ and 301 PG is used and the active ingredient is calculated from its 50% active ingredient content in Reach 301 AQ and 30% active ingredient content in Reach 301 PG. The above proportions are based on the final product including propellant.

Dipropylene glycol

(All Amounts in Weight %)

(Table3.doc)

Claims

We claim:

1. A single phase liquid composition suitable for discharge as an aerosol antiperspirant composition comprising: (a) an antiperspirant ingredient consisting of an aluminum antiperspirant compound present in an amount of at least 6% by weight of the total composition;

(b) a polyol, complexed with the antiperspirant compound or free thereof, present in an amount of at least 14% by weight of the total composition; and

(c) an aerosol propellant and/or carrier present in an amount up to 80% by weight of the total composition, which propellant and/or carrier assist in solubilizing the aluminum antiperspirant complex and polyol.

2. The single phase liquid composition of claim 1 and further wherein the weight ratio of polyol to aluminum antiperspirant is at least 0.6 to 1.

3. The composition according to Claim 2, wherein the solubilizing component is present in an amount from 15 to 65 wt.% and is selected from the group consisting of aerosol propellants and polyol solubilizing carriers in which the polyol and active component are soluble and mixtures thereof.

4. The composition according to Claim 3 wherein the solubilizing component is a propellant selected from the group consisting of lower alkyl ethers, non- chlorinated fluorocarbons, low boiling hydrocarbons and mixtures thereof.

5. A composition according to Claim 4 wherein the composition includes a polyol solubilizing carrier selected from the group consisting of lower alkyl alcohols, esters, ethers, glycols and ketones, water, lower polyalkylene glycols, and mixtures thereof.

6. A composition according to Claim 5 wherein said propellant is selected from the group consisting of lower alkyl ethers, non-chlorinated fluorocarbons, low boiling hydrocarbons and mixtures thereof.

7. A composition according to Claim 6 wherein said composition contains 20 wt.% to 40 wt.% propellant and the propellant includes dimethyl ether.

8. A composition according to Claim 7 wherein said composition contains a polyol solubilizing carrier from 5 wt.% - 40 wt.% selected from the group consisting of alcohol, water or mixtures thereof.

9. A composition according to Claim 8 wherein said polyol is selected from the group consisting of lower alkyl polyols having two or three hydroxyl groups.

10. A single phase aerosol composition comprising:

(a) an antiperspirant ingredient consisting of at least 6 wt.% of aluminum antiperspirant compound; (b) at least 14 wt.% of a lower alkyl glycol wherein the glycol to antiperspirant equals or exceeds 0.6 parts glycol to 1 part antiperspirant by weight;

(c) 5 - 40 wt.% of a polyol solubilizing carrier selected from the group consisting of an alcohol, water and mixtures thereof; and

(d) 15 - 45 wt.% of a propellant; said carrier and propellant present in from 20 wt.% - 65 wt.% and effective to form a single phase composition with the other components; and further said single phase composition effective to maintain a single phase composition as the propellant is volatilized after dispensing of the composition from an aerosol container.

11. The single phase composition of Claim 10, wherein the composition is anhydrous and contains 6 - 30 wt.% antiperspirant, 14 - 55 wt.% glycol selected from the group consisting of propylene glycol, dipropylene glycol and mixtures thereof, 5 - 40 wt.% alcohol and 15 - 45 wt.% dimethyl ether.

12. A single phase composition according to Claim 10, wherein the composition contains from 6 wt.% - 30 wt.% antiperspirant, 14 - 55 wt.% glycol selected from the group consisting of propylene glycol, dipropylene glycol and mixtures thereof, 5 - 40 wt.% water and 15 - 45 wt.% dimethyl ether.

13. A single phase antiperspirant composition for use in a pressurized system comprising:

(a) fragrance;

(b) an antiperspirant ingredient consisting of 6 - 25 wt.% aluminum antiperspirant compound; (c) 15 - 55 wt.% lower alkyl polyol of 2 or 3 hydroxyl groups wherein the weight ratio of polyol to antiperspirant is equal to or exceeds 0.6/1 by weight;

(d) 5-40 wt.% of a polyol solubilizing carrier selected from the group consisting of alcohol, water and mixtures thereof; and

(e) 15 - 45 wt.% dimethyl ether; wherein the total volatile organic compound content of the mixture is 60% by weight or less.