Drug – bio-affecting and body treating compositions – Anti-perspirants or perspiration deodorants
Reexamination Certificate
2002-05-09
2004-04-27
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Anti-perspirants or perspiration deodorants
C424S066000, C424S068000, C424S400000, C424S401000
Reexamination Certificate
active
06726901
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to antiperspirant compositions comprising an aluminum-zirconium antiperspirant salt with a low metal to chloride ratio (e.g., M:Cl=0.9-1.3) and a stabilizing basic material.
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.
The enhanced efficacy salts are typically differentiated from conventional antiperspirant salts by reference to the various aluminum peaks that can be identified when the salt is analyzed by size exclusion chromatography, typically HPLC (high pressure liquid chromatography). A suitable chromatographic technique must be capable of resolving the Al into at least four distinct peaks (labeled peaks 2 (or 1+2), 3, 4 and 5), such as is shown in U.S. Pat. No. 5,330,751. Up to now, the enhanced efficacy salts have been described as having an increased peak 4 content or an increased peak 4 to peak 3 ratio compared to conventional salts. (In some cases, enhanced salts have been described as having increased “band III” content by some authors, depending on the chromatographic technique and nomenclature employed. Generally, bands I, II, III and IV of one system correspond to peaks 1+2 (band I), 3, 4 and 5 of the other system.) Typically, the known enhanced efficacy salts (measured as 10% solutions) have an HPLC peak 4 to peak 3 area ratio of 0.5 or higher, preferably at least 0.7, with at least 70%, preferably at least 80%, of the aluminum contained in peaks 3 and 4. Thus, the enhanced salts will typically have a peak 4 content of at least 30% of the total aluminum contained in all the peaks (measured by peak area). In contrast, conventional non-enhanced antiperspirant salts have a negligible peak 4 content or a peak 4 to 3 area ratio less than 0.2, typically about 0.1.
Prior to the discovery of the enhanced Al—Zr salts as described above, 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. However, this efficacy claim does not appear to have gained acceptance in the industry. 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.
In WO 02/34223 there is described a new type of enhanced efficacy aluminum-zirconium antiperspirant salt having a high peak 5 aluminum content. These salts, which are given the shorthand designation “E
5
AZCH”, generally exhibit an HPLC peak 5 area content greater than 33%, preferably greater than 45%. This disclosure suggests that preferred salts will have a metal (Al+Zr) to chloride ratio of about 0.90 to about 1.00.
In U.S. Pat. No. 6,024,945 there are described aerosol antiperspirant compositions which include certain additives to prevent the formation of toxic compounds that may result from the reaction of aluminum chlorohydrate and the propellant, 1,1-difluoroethane. The additives include, for example, an amino acid, an amino compound, a metal glycinate, a hydrotalcite, a complex aluminum buffering agent, etc.
Aluminum-zirconium antiperspirant salts which have a low metal to chloride (or halogen) ratio are very acidic. Such acidic salts are difficult to formulate into conventional anhydrous compositions because they can destabilize or degrade the composition or decompose one or more of its components. In the case of a solid product, the hardness of the product will deteriorate significantly over time. In the case of a cream or soft solid product, the viscosity of the product will deteriorate. In adddition, such products can have an undesirable acid odor. While it is possible to neutralize some of the salt acidity by adding some basic material to the aqueous salt (e.g., by addition of amino acid to increase the amino acid to zirconium ratio) during its manufacture, this type of neutralization is a chemical process that can alter the chemistry of the salts being neutralized. It has been found that such neutralization can adversely impact the antiperspirant efficacy of the salt so that it does not achieve its highest possible efficacy.
It would be highly desirable to provide a stabilized anhydrous salt with a low metal to chloride ratio. Such a composition should retain the inherent efficacy of the salt, while being stable against degradation under normal storage conditions. Also, it is highly desirable to eliminate the acid odor from products containing antiperspirant salts with a low metal to chloride ratio.
SUMMARY OF THE INVENTION
The present invention embraces an anhydrous topical antiperspirant composition comprising a dermatologically acceptable carrier and a perspiration reducing effective amount of a particulate antiperspirant salt suspended in the carrier. The antiperspirant salt comprises an aluminum-zirconium chlorohydrate having a metal to chloride ratio between about 0.9 and about 1.3. The composition also includes, separate from the antiperspirant salt, a stabilizing basic material (as hereinafter described) in an amount sufficient to prevent degradation of the antiperspirant composition or to minimize acid odor. The present invention also embraces a method of reducing perspiration from human skin by applying the aforementioned antiperspirant composition.
DETAILED DESCRIPTION OF THE INVENTION
The anhydrous topical antiperspirant composition of the present invention comprises a dermatologically acceptable carrier, a perspiration reducing effective amount of a particulate antiperspirant salt suspended in the carrier, and, as a separate material from said antiperspirant salt, a stabilizing basic material in an amount sufficient to prevent degradation of the antiperspirant composition. The term “anhydrous” as used herein means that the composition is substantially free (that is, contains less than about 2%, preferably less than 1%, and most preferably less than 0.1% by weight) of free water (excluding any water of hydration associated with the antiperspirant salt or other components of the composition).
The particulate antiperspirant salt comprises an aluminum-zirconium chlorohydrate having a metal to chloride ratio between about 0.9 and about 1.3, preferably between about 0.9 and 1.1, and most preferably between about 0.9 and 1.0. The aluminum-zirconium chlorohydrate will 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 0.77 to 1.11 (which corresponds to a metal (Al+Zr) to chloride ratio of about 1.3-0.9), preferably about 0.91 to about 1.11 (which corresponds to M:Cl=1.1-0.9), and most preferably about 1.00 to about 1.11 (which corresponds to M:Cl=1.0-0.9). 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). Normally these salts will also include an amino acid associated with them to prevent polymerization of the zirconium species during manufacture. Typical amino acids include glycine, alanine, valine, serine, leucine, and aminobutyric acid, with g
Sane Jayant N.
Shen Yan-Fei
Yin Yuling
Dodson Shelley A.
The Gillette Company
Williams Stephan P.
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