Drug – bio-affecting and body treating compositions – Anti-perspirants or perspiration deodorants
Reexamination Certificate
2001-05-23
2002-07-09
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Anti-perspirants or perspiration deodorants
C424S066000, C424S068000, C424S400000, C424S401000
Reexamination Certificate
active
06416750
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a low temperature process for making stable anhydrous solutions of aluminum-containing antiperspirant active in selected polyol solvents.
BACKGROUND OF THE INVENTION
There are many antiperspirant products commercially available or otherwise known for use in controlling or inhibiting underarm perspiration and odor. These formulations typically contain an antiperspirant active material such as an aluminum or zirconium salt in a suitable carrier such as an aqueous or alcohol solvent. The antiperspirant active can be in the form of solid dispersed particulates or solubilized with a solvent matrix.
Clear antiperspirant products have become increasingly popular among consumers over the past several years. These products typically contain antiperspirant active materials solubilized in a suitable liquid carrier. These compositions can be aqueous or anhydrous, but are often formulated as anhydrous formulations to provide drier skin feel during and after application to the underarm. Solubilized antiperspirant actives in anhydrous systems are most typically solubilized with solvents such as ethanol, propylene glycol, polyethylene glycols, and other monohydric or polyhydric materials.
One method for making solubilized antiperspirant active for use in antiperspirant products begins with the preparation of antiperspirant active solutions containing water, polyhydric alcohols, and an aluminum-containing active or aluminum and zirconium-containing active. These aqueous polyhydric alcohol solutions are then subjected to spray drying or other rapid drying method to thus form substantially anhydrous powders containing aluminum or aluminum and zirconium active and polyhydric alcohol associated with or otherwise bound to the active material within the powders. These spray dried powders are then combined with a suitable solvent, most typically a polyol solvent such as propylene glycol, at solvent temperatures generally exceeding about 90° C., to thus form a finished or intermediate antiperspirant product containing solubilized antiperspirant active.
It has now been found, however, that the above-described process for making solubilized antiperspirant active can be improved by using low temperature solubilization of the spray dried active in a polyol solvent. This can be accomplished by 1) selecting the polyol or other anhydrous solvent added to the antiperspirant active prior to spray drying, 2) selecting certain polyol solvents that are then added to the spray dried antiperspirant active to solubilize the spray dried solid, and 3) maintaining solvent solubilization temperatures after spray drying of less than about 85° C. The first selected polyol or anhydrous solvent must have a solubility parameter of from about 9 (cal/cm
3
)
0.5
to about 15 (cal/cm
3
)
0.5
, whereas the second selected polyol solvent that solubilizes the spray dried material must be a 1,2-diol having at least 4 adjacent carbon atoms. The lower solubilization temperatures after spray drying allow for less energy intensive processing and improved processing and formulation flexibility, especially when processing or formulating with relatively heat-labile materials.
SUMMARY OF THE INVENTION
The present invention is directed to a process of making stable anhydrous antiperspirant active solutions, which process comprises the steps of: (A) preparing an aqueous antiperspirant active solution comprising an aluminum-containing antiperspirant active, water, and an anhydrous solvent having a solubility parameter of from about 9 (cal/cm
3
)
0.5
to about 15 (cal/cm
3
)
0.5
; (B) spray-drying the aqueous solution to form a solid powder comprising aluminum-containing antiperspirant active and the anhydrous solvent; and (C) dissolving the solid powder in a second anhydrous solvent at a temperature of not more than about 85° C., the second anhydrous solvent comprising a 1,2-diol solvent having at least 4 carbon atoms, to thereby form a stable anhydrous antiperspirant active solution comprising solubilized aluminum-containing antiperspirant active and the 1,2-diol solvent.
It has been found that the stable antiperspirant active solutions provided by the process of the present invention are especially useful as manufacturing intermediates in providing improved formulation and process flexibility when preparing antiperspirant consumer products, especially those products that are clear or translucent in appearance. It has been found that the selection of the anhydrous solvent used in the spray-drying step (selected solubility parameter) and the polyol solvent used in the active dissolution (1,2-diol have at least 4 adjacent carbon atoms), among the many polyol and anhydrous solvents known in the antiperspirant formulation art, allow for low temperature dissolution of the spray dried antiperspirant active and improved formulation and manufacturing flexibility in preparing a clear or low residue antiperspirant product containing solubilized antiperspirant active.
DETAILED DESCRIPTION
The process of the present invention, including essential and optional characteristics thereof, are described in detail hereinafter. All percentages, parts and ratios as used herein are by weight of the total referenced composition, unless otherwise specified. All such weights as they pertain to listed ingredients are based on the active level and, therefore, do not include solvents or by-products that may be included in commercially available materials, unless otherwise specified.
The term “anhydrous” as used herein, unless otherwise specified, means that the referenced material or composition contains less than about 20%, preferably less than about 10%, more preferably less than about 5%, most preferably zero percent, by weight of water.
The process of the present invention can comprise, consist of, or consist essentially of the essential elements and limitations of the invention described herein, as well as any additional or optional ingredients, components, or limitations described herein or otherwise useful in antiperspirant applications.
PROCESS
The process of the present invention provides a more efficient or alternative method for making anhydrous antiperspirant compositions comprising solubilized antiperspirant active. The anhydrous antiperspirant compositions made in accordance with the process of the present invention can be used as finished antiperspirant products for consumer application, or as manufacturing intermediates to formulate any of a variety of anhydrous antiperspirant products containing solubilized antiperspirant active or other antiperspirant active derived from solubilized antiperspirant active.
A) Preparation of Aqueous Active Solution
The first step of the process of the present invention is the preparation of an aqueous antiperspirant active solution comprising an aluminum-containing antiperspirant active, water and an anhydrous solvent having a solubility parameter of from about 9 (cal/cm
3
)
0.5
to about 15 (cal/cm
3
)
0.5
. Many such aqueous antiperspirant active solutions are commercially available and an be used in the process herein, or such aqueous solutions can be prepared by methods well known or otherwise described in the antiperspirant arts for making solubilized aluminum-containing antiperspirant active, non-limiting examples of which include U.S. Pat. No. 5,463,098 Giovanniello et al.); U.S. Pat. No. 5,643,558 (Provancal et al.); U.S. Pat. No. 4,781,917 (Luebbe et al.); which descriptions are incorporated herein by reference.
The first step of the process of the present invention is the obtaining or otherwise preparing of an aqueous antiperspirant active solution preferably having from about 5% to about 90%, more preferably from about 20% to about 60%, by weight of an anhydrous solvent having the requisite solubility parameter; preferably from about 5% to about 70%, more preferably from about 5% to about 50%, by weight of water; and preferably from about 5% to about 40%, more preferably from about 10% to about 30%, by weight of the aluminum-containing antiperspirant active.
Th
Harper Thomas Lee
Mehta Shailesh
Rosenberg Allan Herbert
Dodson Shelley A.
Glynn, Esq. Kenneth P.
Somerville Technology Group, Inc.
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