Drug – bio-affecting and body treating compositions – Anti-perspirants or perspiration deodorants
Reexamination Certificate
2002-06-19
2003-12-16
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Anti-perspirants or perspiration deodorants
C424S066000, C424S068000, C424S400000, C424S401000
Reexamination Certificate
active
06663854
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to aluminum-zirconium antiperspirant salts made with zirconium salts having a low Zr:Cl ratio. The present invention also embraces methods of making these antiperspirant salts and compositions containing these antiperspirant salts.
Aluminum-zirconium antiperspirant salts have been known for several decades. See, for example, U.S. Pat. No. 2,814,585 (Daley), U.S. Pat. No. 2,854,382 (Grad), GB 1,353,916 (Bolich), U.S. Pat. No. 4,331,609 (Orr), U.S. Pat. No. 4,775,528 (Callaghan), U.S. Pat. No. 4,871,525 (Giovanniello), U.S. Pat. No. 4,900,534 (Inward), U.S. Pat. No. 5,225,187 (Carmody), U.S. Pat. No. 5,296,623 (Katsoulis), U.S. Pat. No. 5,330,751 (Curtin), EP 653,203 (Rosenberg), U.S. Pat. No. 5,718,876 (Parekh) and U.S. Pat. No. 5,955,064 (Giovanniello). Some of these aluminum-zirconium antiperspirant salts are described as having enhanced efficacy, which means that they provide greater sweat reduction than conventional antiperspirant salts. EP 653,203 (Rosenberg) suggests that such salts are improved by maintaining the molecular weight of the zirconium species as low as possible.
Prior to the discovery of the enhanced Al—Zr salts, U.S. Pat. No. 4,331,609 suggested that Al—Zr salts with a metal to chloride ratio below about 1.3 (e.g., 1.25) may be more efficacious than salts with a higher metal to chloride ratio. In U.S. Pat. No. 6,126,928 there are described certain polyhydric alcohol solutions of the salts described in the aforementioned '609 patent. More recently, U.S. Pat. No. 6,375,937 described aluminum-zirconium tetrachlorohydrex glycine salts having a metal to chloride ratio in the range of 0.9 to 1.2 and a glycine to zirconium ratio greater than 1.3. None of these disclosures suggest that any advantage is obtained through the use of a particular zirconium species.
SUMMARY OF THE INVENTION
The present invention embraces enhanced efficacy aluminum-zirconium chlorohydrate antiperspirant salts having a metal (Al+Zr) to chloride ratio of about 0.9 to about 1.2, preferably about 0.9 to about 1.1, most preferably about 0.9 to about 1.0. To achieve the highest possible antiperspirant efficacy, these salts are made with or include a zirconium hydroxychloride of the formula Zr(OH)
4−b
Cl
b
wherein b is about 2.8 to about 4.0, preferably about 3.2 to about 4.0, so that the Zr:Cl ratio in said zirconium hydroxychloride is about 0.36 to about 0.25, preferably about 0.31 to about 0.25. The present invention also embraces methods of making such antiperspirant salts and aqueous solutions of such antiperspirant salts. The present invention further embraces topical compositions comprising a dermatologically acceptable carrier and a perspiration reducing effective amount of an aluminum-zirconium antiperspirant salt as described above.
DETAILED DESCRIPTION OF THE INVENTION
The present invention embraces enhanced efficacy aluminum-zirconium chlorohydrate antiperspirant salts having a metal (Al+Zr) to chloride ratio of about 0.9 to about 1.2, preferably about 0.9 to about 1.1, most preferably about 0.9 to about 1.0. The Al—Zr salts generally have the empirical formula Al
n
Zr(OH)
[3n+4−m(n+1)]
(Cl)
[m(n+1)]
where n is 2.0 to 10.0, preferably 3.0 to 8.0, and m is about 0.83 to about 1.11 (which corresponds to M:Cl≅1.2-0.9), preferably about 0.90 to about 1.11 (which corresponds to M:Cl≅1.1-0.9), and more preferably about 1.00 to about 1.11 (which corresponds to M:Cl≅1.0-0.9). These salts also will typically include an amino acid such as glycine, alanine, valine, serine, leucine, or aminobutyric acid, preferably glycine, generally in an amount to provide an amino acid to zirconium ratio (e.g., Gly:Zr) of about 0.8 to about 4.0, preferably about 1.0 to about 2.0. These salts also generally have some water of hydration associated with them, typically on the order of 1 to 5 moles per mole of salt (typically, about 1% to about 16%, more typically about 4% to about 13% by weight). These salts are generally referred to as aluminum-zirconium tetrachlorohydrates when the Al:Zr ratio is between 2 and 6 and as aluminum-zirconium octachlorohydrates when the Al:Zr ratio is between 6 and 10.
A critical feature of the present invention is that the aluminum-zirconium chlorohydrate salts must be made with or include a zirconium hydroxychloride having a low Zr:Cl ratio. The Zr:Cl ratio preferably will be about 0.25 to about 0.36, more preferably about 0.25 to about 0.31, and most preferably about 0.25 to about 0.29. Preferred zirconium salts are those having the general formula Zr(OH)
4−b
Cl
b
wherein b is about 2.8 to about 4.0 (i.e., Zr:Cl ≅0.36-0.25), more preferably about 3.2 to about 4.0 (i.e., Zr:Cl≅0.31-0.25), most preferably about 3.4 to about 4.0 (Zr:Cl≅0.29-0.25). (It should be noted that when b is 4, the zirconium salt is essentially ZrCl
4
.) The zirconium salts, when used as a powder, generally have some water of hydration associated with them, typically on the order of 1 to 7 moles per mole of salt. In addition, the zirconium salts will usually include an amino acid, as described above, to prevent gellation in aqueous solution. Zirconium salts with a low Zr:Cl ratio are preferred because such salts appear to have a lower molecular weight than other zirconium salts and appear to maintain the lower molecular weight form even after being combined with the aluminum salt to form the aluminum-zirconium chlorohydrate. It is theorized that the presence of the low molecular weight zirconium species results in higher antiperspirant efficacy in the final Al—Zr salt. In addition, the use of zirconium salts with a low Zr:Cl ratio also facilitates the manufacture of the Al—Zr salt with a low metal:Cl ratio.
The Al—Zr salt compositions of the present invention are manufactured by mixing in an aqueous solution an aluminum antiperspirant salt (preferably an enhanced aluminum antiperspirant salt as described below) and a zirconium hydroxychloride salt (as described above), each salt being present in an amount to provide the desired Al:Zr molar ratio, and including in the aqueous solution sufficient chloride ion to provide the desired metal:chloride (M:Cl) ratio (i.e., about 0.9 to about 1.2, preferably about 0.9 to about 1.1, most preferably about 0.9 to about 1.0). If there is insufficient chloride ion provided by the aluminum and zirconium salts, additional chloride ion may be provided, for example, by addition of an appropriate amount of HCi (or other suitable chloride source such as AlCl
3
). Typically the mixing of components will take about 0.25 to 5 hours at room temperature (20-25° C.). The aqueous solution of Al—Zr salt may be used or stored as an aqueous solution, or it may be spray dried or vacuum dried to obtain the salt in solid powder form. When the aluminum antiperspirant salt utilized is one with an elevated HPLC peak 4:3 area ratio, then preferably the Al—Zr salt will be dried to a solid while the peak 4:3 area ratio is above 0.4 to obtain a salt with maximum efficacy.
As an alternative to the above-described solution process, it is also possible to dry blend an aluminum antiperspirant salt with the zirconium hydroxychloride, provided that the molar quantities of Al, Zr, and Cl in the starting components that are blended are such as to provide the correct molar ratios of Al:Zr and M:Cl in the final product.
Preferred aluminum salts for use as starting materials are those having the general formula Al
2
(OH)
6−a
Cl
a
wherein a is about 0.3 to about 5, preferably about 0.8 to about 2.5, more preferably about 1 to about 2 (such that the Al to Cl mole ratio is about 0.9:1 to about 2.1:1). These salts generally have some water of hydration associated with them, typically on the order of 1 to 6 moles per mole of salt. Most preferably the aluminum salt is aluminum chlorohydrate, especially 5/6 basic aluminum chlorohydrate where a is about 1, such that the aluminum to chlorine mole ratio is about 1.9:1 to 2.1:1, typically about 1.95:1. Alum
Carrillo Angel L.
Oryszczak Richard
Shen Yan-Fei
Dodson Shelley A.
Williams Stephen P.
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