Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-04-30
2002-10-15
Hartley, Michael G. (Department: 1619)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
Reexamination Certificate
active
06464989
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to emulsions containing Tea Tree Oil.
BACKGROUND OF THE INVENTION
Tea Tree Oil (TTO) is isolated by distilling the oil contained in the stems and leaves of the paperbark tree
Melaleuca alternafolia.
TTO has unique medicinal properties including antimicrobial and antifungal characteristics. Additionally, TTO provides a soothing sensation when in contact with a person's skin. When applied as a neat oil, however, TTO quickly evaporates diminishing its effects. To prolong its effects, it is desirable to apply TTO in a form that will both remain in contact with the skin and deliver the highest concentration of TTO possible.
Medicaments, such as the original Melan-Gel(™) formulation, containing TTO are typically packaged in plastic or glass jars. Opening and closing such containers exposes a relatively large surface area of the medicament to air, which provides an opportunity for evaporation of the TTO. Furthermore, repeated exposure of the medicament to air can facilitate oxidation of some of the chemical components of the medicament. Oxidation can change the chemical makeup of the medicament, which may affect the medicament's effectiveness.
TTO can be administered as a gel suspension. At high TTO concentrations, however, TTO tends to separate from the gel base formula, corrupting the gel suspension. Moreover, changes in temperature and/or applying physical shear forces, such as kneading a gel suspension, tend to accentuate the separation difficulties attributed to TTO. Thus, it is difficult to suspend high concentrations of TTO in gel or waxy base formula because as the TTO concentration increases it tends to thin the wax base.
As such, currently known TTO formulations containing higher concentrations of TTO will separate into their base ingredients when the gel is packaged in a flexible tube. In contrast, current TTO formulations are stable when packaged in glass or plastic jars or small bottles. These formulations are referred to as “jar” formulations. It is thought that since the wax matrix sets up in a jar it prevents TTO from separating out of the wax matrix. In addition, TTO evaporates more quickly when packaged in a jar as opposed to a tube due to the larger exposed surface area and the lack of an air tight lid seal on jars after they are first opened. Accordingly, it is currently impractical to offer TTO formulations in tightly sealed containers and/or flexible tubes.
SUMMARY OF THE INVENTION
The present invention involves the discovery that the certain combinations of tea tree oil and emulsifiers produce a tea tree oil emulsion or tea tree oil composition that remains stable. The combinations can contain waxes, oils, emulsifiers, and TTO among other ingredients. The present invention further involves a method for producing such a tea tree oil emulsion and an article of manufacture containing the emulsion.
In one aspect, the invention features a tea tree oil emulsion including tea tree oil at a concentration greater than about 20% on a weight by weight basis, an emulsifier, and a wax. Such an emulsion or composition can be stable at room temperature. In some embodiments, the TTO emulsion or composition is visually stable.
In another embodiment, the emulsion also contains wheat germ oil and/or including pentaerythritol ether. The pentaerythritol ether may be at a concentration ranging from about 15% to about 25% on a weight by weight basis.
The tea tree oil concentration can be increased to any concentration above 20% including at least about 22, 23, 24, 25, 26, 27, 28, 29, or 30 percent on a weight by weight basis. In certain embodiments, the tea tree oil is of a pharmaceutical grade tea tree oil. As such, the tea tree oil may have a terpenene-4-ol concentration greater than about 36% and a cineol concentration less than about 7%.
In other embodiments, the emulsifier is at a concentration less than about 25% on a weight by weight basis, ranges from about 0.5% to about 23% on a weight by weight basis, ranges from about 0.5% to about 10% on a weight by weight basis, or is at a concentration of about 9% on a weight by weight basis. Useful emulsifiers may be used alone or in combination and may be selected from the group consisting of stearic acid, glyceryl stearate, polyethyleneglycol 100 stearate, steareth-21, polyoxyethylene(2) stearyl ether, steareth-2, polysorbate 20, cetearyl alcohol, and polysorbate 60. Glyceryl stearate and polyethyleneglycol 100 stearate may be also used alone or in combination as a blend. Other emulsifiers may also be blended.
In some embodiments, the emulsifiers are used in combination and may be at concentrations where stearic acid is at a concentration concentrations ranging from about 3% to about 8% on a weight by weight basis, glyceryl stearate and polyethylene glycol 100 stearate are at a concentration ranging from about 1% to about 5% on a weight by weight basis, steareth-21 is at a concentration ranging from about 0.5% to about 5.0% on a weight by weight basis, and steareth-2 is at a concentration ranging from about 0.5% to about 5.0% on a weight by weight basis.
In other embodiments, the TTO emulsion includes wheat germ oil, cocoa butter, beeswax, ozokerite wax, pentaerythritol ether, vitamin E acetate, vitamin A, and vitamin D3. These additional substances may be used alone or in combination. For example, the wheat germ oil concentration can range from about 15% to 25%, the cocoa butter concentration can range from about 15% to about 25%, the, beeswax concentration can range from about 3% to about 8%, the ozokerite wax concentration can range from about 1% to about 5%, the pentaerythritol ether can range from about 15% to about 25%, the vitamin E acetate concentration can range from about 0.1% to about 2%, the vitamin A concentration can range from about 0.1% to about 2 percent, the vitamin D concentration can range from about 0.1% to about 2 percent. In other embodiments, the emulsifier concentration ranges from about 0.5% to about 23%.
In other embodiments, the TTO emulsion has a shelf life of 1 year, 18 months, 2 years, or more.
In another aspect, the invention features, a method for producing a tea tree oil emulsion including the steps of: a) mixing and heating an emulsifier and a wax to a temperature effective for dissolving the emulsifier and the wax thereby forming an emulsifier and wax combination; b) cooling the combination; c) adding tea tree oil to the cooled combination to form a tea tree oil mixture; and d) emulsifying the mixture forming a tea tree emulsion, the emulsion having a tea tree oil concentration of at least about 20% on a weight by weight basis, the emulsion being stable at room temperature.
In other embodiments, the heating step of the method includes heating the emulsifier and the wax to a temperature of about 80° C. Also, the method can include cooling the combination to a temperature of about 70° C. The heating and cooling steps can be used together in a single method. In other embodiments, a second emulsifier is added to the combination after the cooling step. The second emulsifier can be a blend of glyceryl stearate and polyethylene glycol 100 stearate.
In another aspect, the invention features an article of manufacture including a tea tree oil emulsion including a tea tree oil concentration greater than about 20% on a weight by weight basis, an emulsifier, and a wax, the emulsion packaged in a flexible container suitable for dispensing the tea tree oil emulsion, the emulsion remaining stable while contained within the flexible container. In some embodiments, the article of manufacture may reduce TTO exaporation and/or oxidation of the ingredients. The article of manufacture can be used with any of the mentioned TTO emulsion embodiments disclosed herein.
Advantages of the invention include being able to package a TTO emulsion or composition in a flexible tube wherein the TTO emulsion remains stable in the flexible tube. Stable TTO emulsions can then be dispensed from a flexible tube as unfractionated, and thus uniform, dosages of TTO. Accordingly, the T
Dillon Kathy
Korth Kevin
Montgomery David
Zehntner Becky
Fish & Richardson P.C. P.A.
Hartley Michael G.
Melaleuca Incorporated
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