WO2000062738A1

WO2000062738A1 - Breath freshening lipstick comprising menthol

Info

Publication number: WO2000062738A1
Application number: PCT/EP2000/002217
Authority: WO
Inventors: Alan Joel Meyers; Celeste Anne Lutrario; Marianne Elliott; Lee Ann Gallagher
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 1999-04-16
Filing date: 2000-03-13
Publication date: 2000-10-26
Also published as: AU3288900A

Abstract

A lipstick is provided for freshening the breath and reducing oral malodor. This lipstick utilises an antibacterial agent in combination with menthol as the active components. Most preferred as the antibacterial agent are zinc salts, especially zinc citrate. Further components of the lipstick include a lipophilic material such as a wax and usually colorants. Water may be included at levels ranging up to about 25 % by weight.

Description

BREATH FRESHENING LIPSTICK COMPRISING MENTHOL

BACKGROUND OF THE INVENTION

Field of the Invention

The invention concerns a lipstick for freshening breath and controlling oral malodor.

The Related Art

Foods and natural decay generate odors within the oral cavity. These are apt to remain on the breath long after meals. Particular offenders in the food category are liquors, garlic, fish and leeks. Smoking also generates smells. Foul breath sometimes arouses unpleasant responses in those near the generating source. Malodor is also an indication of oral and other body organ illnesses.

Traditionally bad breath has been inhibited through use of toothpaste and oral rinses. Application of these products ordinarily requires a lavatory facility. Ordinarily use of these products is limited to times just subsequent to a meal . Protection may not linger for long periods between meals, especially where brushing or rinsing opportunities are unavailable.

EP-A-0549267 (Dunphy et al . ) discloses a lip-treatment composition including a base oil, water and a structurant, and at least one active agent for the treatment of the lips, gums, teeth, oral mucosa and the throat. Listed among a variety of active agents are zinc salts, triclosan and other antimicrobial agents. These are said to be effective against breath malodour. Unfortunately the systems disclosed by that publication do not always provide immediate delivery of benefit i.e. reduction in oral malodor. When the benefit does begin, it may be insufficient to be fully effective.

Accordingly, embodiments of the present invention may provide products for freshening breath and reducing oral malodor which are effective immediately and thereafter for relatively long time periods.

Another aspect of embodiments of the present invention is the provision of products for freshening breath and reducing malodor which are easy to apply and require no lavatory facilities for their application.

These and other advantages of the present invention will become more readily apparent from consideration of the following summary and detailed discussion.

SUMMARY OF THE INVENTION

A lipstick is provided for freshening breath and controlling oral malodor. The lipstick comprises:

(i) from about 10 to about 99% of a lipophilic material ; (ii) from about 0.01 to about 10% by weight of an antibacterial agent; and

(iii) from about 0.01 to about 2% of menthol. DETAILED DESCRIPTION OF THE INVENTION

The applicant company has found that breath freshening and the reduction of oral malodor is achievable through a specially formulated lipstick. Unlike toothpaste and mouth rinses, the specially formulated lipsticks of the present invention require no running water for their application. They also release a constant stream of oral malodor reductant for extended periods of time. Antibacterial agents in combination with menthol serve as the active agents. Immediately after application of the lipstick, menthol is quickly released to mask any malodour. As the immediate effect of menthol declines, the antibacterial agent, which is released more slowly from the lipstick, begins to migrate to the oral cavity.

The antibacterial agent (s) are typically present in the compositions of the invention in an amount of from about 0.01 to about 10%, preferably from about 0.1 to about 5%, optimally from about 0.5 to about 3% by weight. Suitable antibacterial agents include zinc salts, quaternary ammonium compounds and chlorinated hydrocarbons. Illustrative of the quaternary ammonium compounds are pyridinium salts (such as cetyl pyridinium chloride) and benzalkonium salts (such as dimethyl benzylammonium chloride) and chlorhexidines . Illustrative of the chlorinated hydrocarbons are salicylanides (such as 4 ' , 5-dibromosalicylanlide) and halogenated diphenyl ethers such as 2 , 4 , 4 ' -trichloro-2 ' - hydroxydiphenyl ether (commonly known as triclosan) . Zinc salts are the most preferred antibacterial agents. Examples of zinc salts that may be employed are those having organic or inorganic anions selected from the group consisting of acetate, benzoate, borate, bromide, carbonate, citrate, chloride, glycerophosphate, hexafluorosilicate, di- lactate (trihydrate) , nitrate, phenolsulfonate, glycinate, silicate, alkanoates having 8 to 18 carbon atoms, such as zinc stearate, salicylate, stannate, sulfate, tannate, titanate, tetrafluoroborate, tartrate and mixtures thereof. The zinc salts may be used singly or in admixture.

The term "zinc salt" refers to any zinc compound capable of dissociating into zinc ions at a temperature of about 37°C, as well as to zinc ions formed in an aqueous medium such as a mouthwash or oral salivary secretions.

Most preferably the zinc salt is a zinc citrate such as hydrated zinc citrate. For the purposes of this specification zinc compounds such as zinc oxide are not zinc salts.

The compositions of the invention typically contain menthol in an amount of from about 0.01 to about 2%, preferably from about 0.05 to about 1%, optimally from about 0.1 to about 0.5% by weight.

Menthol may be delivered directly or released from a bound menthol substance. The term "bound menthol substance" refers to a physical combination of free menthol releasably complexed or encapsulated by a binding or enrobing substance. Materials suitable for encapsulating the menthol include polysaccharides such as starch or modified starch; synthetic polymers and copolymers such as polyvinyl alcohol, acrylics or polyurethanes ; vegetable gums such as gelatin, guar or carrageenan gums, and combinations thereof.

Complexes of menthol with starches such as cyclodextrin, clathrates, clays and zeolites may be formed. Most preferred are complexes of menthol with cyclodextrin. The term "cyclodextrin" refers to any known natural cyclodextrin and substituted and unsubstituted analogs and derivatives thereof. Examples of derivatives include methy- beta-cyclodextrin, hydroxyethyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin. Generically these substances are cyclic oligosaccharides with the ability to form inclusion complexes with a variety of materials. Their ring size is typically from 6 to 12 glucose units, preferably 6, 7 or 8 glucose units. Preferred rings include alpha-cyclodextrin, beta-cyclodextrin and gamma- cyclodextrin, respectively. These substances are available from the Lipo Chemical Company, a subsidiary of Cerestar

Inc. (formally the American Maize Company) . A complex of menthol with beta-cyclodextrin is particularly preferred.

Amounts of the bound menthol substance may range from about 0.1 to about 10%, preferably from about 0.2 to about 2%, optimally from about 0.5 to about 1% by weight based on releasable menthol by weight of the lipstick composition.

The compositions preferably contain an adjunct freshening component to menthol such as anethole. The weight ratio menthol to anethole is typically from about 100:1 to about 1:1, preferably from about 50:1 to about 2:1, optimally from about 30:1 to about 10:1.

An essential element of all lipsticks is a lipophilic material. These materials may be solids (defined as being firm and of a plastic texture at room temperature) or liquids. A combination of a solid and a liquid generally provides structure to the lipstick rendering it solid with plastic texture at room temperature.

Suitable lipophilic liquids may be selected from hydrocarbon oils, fatty acid esters, fatty alcohols and mixtures thereof. Hydrocarbon oils may be either natural or synthetic. Suitable hydrocarbon oils derived from mineral sources include petroleum derived mineral oils, petrolatum and mixtures thereof. Plant sourced oils include saturated and unsaturated fatty acids, for example adipic, caprylic, capric, lauric, myristic, palmitic, stearic and mixtures thereof. Unsaturated fatty acids include linoleic, linolenic, ricinoleic, oleic, elaidic, erucic acids and mixtures thereof. Other vegetable oils include castor bean oil, rapeseed oil, soybean oil, palm kernel oil, babassu kernel oil, coconut oil and mixtures thereof. Fatty alcohols suitable for use in this invention include cetearyl alcohol, cetyl alcohol, myristyl alcohol, stearyl alcohol, isostearyl alcohol, lanolin alcohol, lauryl alcohol, oleyl alcohol and mixtures thereof. Fatty acid esters suitable for use in this invention may be derived from the esterification reaction of C₈-C₂₀ fatty acids with C₁-C₂₀ monohydric and polyhydric alcohols (for example triglycerides) . Illustrative but not limiting examples include cetyl ricinoleate, glycerol oleate, glycerol monostearate, isopropyl lanolate, isopropyl linoleate, isopropyl myristate, ethyl palmitate, isopropyl palmitate, isopropyl isostearate and mixtures thereof.

Suitable solid lipophilic materials typically have a melting point of from about 55°C to about 110°C. These solids include fatty alcohols, fatty acid esters, waxes and mixtures thereof. Substances mentioned above as liquid lipophilic materials and having a melting point within the above range are considered to be solid lipophilic materials. Waxes are a particularly useful type of solid within the context of the present invention. Preferred waxes include those selected from the group consisting of candelilla, beeswax, carnauba, spermaceti, montan, ozokerite, ceresin, paraffin, modified beeswax, bayberry wax, castor wax, macrocrystalline waxes and mixtures thereof.

Amounts of the lipophilic material may range from about 10 to about 99%, preferably from about 30 to about 90%, optimally from about 40 to about 80% by weight of the composition.

Advantageously the lipsticks of the present invention may contain a small amount of water. Small amounts are useful as solubilization systems for the antimicrobial agents, especially the zinc salts so that they may be delivered more readily to the oral cavity as the user wets their lips with the tongue and portions of saliva. High levels of water are undesirable because the lipophilic materials, which form the vast majority of the lipstick, are incompatible with water. Suitable amounts of water may range from about 0.1 to about 25%, preferably from about 1 to about 10%, optimally from about 3 to about 8% by weight of the composition.

Small amounts of water are also useful for the release of menthol from the bound menthol mixtures . Complexing agents such as cyclodextrin and encapsulating agents such as polyvinyl alcohol are soluble in water. The small amount of water dissolves the encapsulating material or acts as a transfer media for menthol complexed cyclodextrins .

The compositions of the invention may also contain one or more antioxidants . Antioxidants can assist in the reduction of malodor by reacting with malodor generating substances found in the mouth. Suitable antioxidants are those selected from green tea, Vitamin C and its derivatives (e.g. ascorbyl palmitate, magnesium ascorbate and tetraisopropyl ascorbate) , chamomile, tocopherol and its derivatives (e.g. tocopheryl palmitate), butylated hydroxytoluene, oryzanol and mixtures thereof. The amounts of antioxidants used is typically from about 0.0001 to 5%, preferably from about 0.01 to about 2%, optimally from about 0.1 to about 1.5% by weight.

Skin protective agents may also be included in lipsticks of the present invention. These include anti- aging substances such as alpha hydroxy acids, beta hydroxy acids and esters thereof (e.g. tridecylsalicylate) , retinol and retinoid esters (e.g. retinyl linoleate) . Amounts of these substances may range from about 0.001 to about 5%, preferably from about 0.1 to about 1% by weight.

Polysaccharides may also be incorporated into the lipstick compositions of the present invention. Suitable polysaccharides include sorbitol available as Neosorb™ and Trehalose . The amounts of polysaccharide may range from about 0.1 to about 10%, preferably from about 0.5 to about 2% by weight .

Emulsifiers may be incorporated into the lipstick compositions of the present invention. The overall concentration of emulsifier may range from about 0.1 to about 30% by weight of the formulation, preferably from about 0.5 to about 20%, optimally between about 2 and 10% by weight .

Suitable emulsifiers include phospholipids . These emulsifiers may contribute to the stability and pleasing appearance of the compositions. Examples of phospholipids include phosphoglycerides , lysophosphoglycerides, sphingomyelins and mixtures thereof. The phospholipid, lecithin is especially preferred.

Fatty acid derivative-type emulsifiers may also be employed, preferably in combination with a phospholipid. These emulsifiers may include monoacyl glycerol, diacyl glycerol and polyglycerol esters and combinations thereof. Especially preferred are glycerol monoalkanoates , for example monoglycerides of sunflower seed oil or palm oil. Colorants may also be included in compositions of the present invention. These substances are normally FD&C approved dyes, pigments and mixtures thereof. Suitable colourants include lake dyes, micas or pearls, iron oxides, titanium oxides, calcium carbonates and mixtures thereof. Particularly suitable are lakes encompassing either a pigment that is extended or reduced with a solid diluent or an organic pigment that is prepared by the precipitation of a water-soluble dye on an absorptive surface. Usually an aluminohydrate . Typical Aluminum Lakes are Yellow # 6 Aluminum Lake, Yellow # 10 Aluminum Lake, Orange # 5 Aluminum Lake, Blue # 1 Aluminum Lake, Red # 3 Aluminum Lake, Red # 27 Aluminum Lake and mixtures thereof. Calcium and barium lakes may also be employed. Bismuth oxychloride is a further useful colorant.

Sunscreens may also be incorporated into lipstick compositions of the present invention. Amounts of the sunscreens may range from about 1 to about 30% by weight of the composition. Organic and inorganic substances may be used as sunscreens. Suitable organic substances typically absorb light in a wavelength range of from about 270 to about 400 nm. Illustrative examples include benzophenone 3,

® octylmethoxycinnamate (Parsol MCX ) , avobenzene,

® commercially available as Parsol 1789 (from Givaudan-Roure

Corporation) and mixtures thereof. Inorganic sunscreens include micronized titanium dioxide and zinc oxides.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word "about" .

The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated.

EXAMPLES 1-10

Lipsticks of the present invention are prepared according to the following compositions.

TABLE I

(Table I continued..../)

TABLE I (continued)

EXAMPLE 11

A biophysical oral malodor prevention study was conducted to determine the efficacy of lipsticks according to the present invention. Female panelists aged 18-65 were enrolled in the study. Twenty-nine panelists qualified to participate, each having scores above 4 (on a breath malodor scale of 1-8) on both days of a two-day trial.

Methods

Oral malodor was evaluated by two trained judges before product application (as a baseline) , immediately following product application (t=0) , 2 hours, and 4 hours after application. Panelists were graded by breathing a slow, steady stream through a straw that was placed through a slit in a booth where each of the judges evaluated their degree of malodor on an 8 point scale.

Scoring by the judges was as follows

Scores of 4 and 5 were relative scores indicating definite malodor, and scores of 6-8 were relative scores indicating intense malodor, but no other descriptors were given. In order for a score to be recorded, both judges needed to be within 1 scoring point of each other. A study coordinator stood behind the partition with the judges to check scores (the judges were separated by a partial wall so that they could not see each others' scores) . This was so that they could tell the panelist to immediately return to a judge when both judges' scores did not match. If by the second try the scores were still not within 1 scoring point of each other, the trained study coordinator would evaluate and score that panelist.

Procedure

Four (4) panelists were randomly chosen at the start of each day to "cycle" (acclimate) the judges, i.e. to acclimatise their olfaction before they started to grade actual baseline readings. After cycling, panelists proceeded to the grading room in groups of 4 to have their breath screened to qualify them for participation in the study. In order to qualify, they needed to score at least at 4 (definite malodor) on a scale of 1-8. Each qualified panelist was assigned randomly to apply one of the two lip products .

Products Tested

A lipstick with a composition essentially identical to that of Example 3 represented a typical composition of the present invention. As a control, a formulation identical to that of the experimental stick except that the formulation lacked menthol, menthol-cyclodextrin, zinc citrate and flavor components was evaluated.

Treatment

Treatment involved application of one of the lip products (either the product or the control) on Day 1, and the other on Day 2 according to a randomization schedule. After application, panelists then proceeded in groups of four to the judging area to be graded immediately after application (t=0), 2 hours, and 4 hours after application.

Analysis

The means of the two judges' scores were obtained and analysis of changes from baseline readings was performed using Microsoft Excel 5.0 and SPSS software. The Wilcoxon Matched-Pairs Signed-Ranks Test was used to test for significance within and between treatments.

Results

Table II lists the statistical results from the study. The baseline malodor scores were not significantly different from each other. Immediately after application of the lipsticks (t=0) , there was a significant decrease in malodor scores for both the control and Example 3 stick compared with the baseline scores. However, there was significantly greater decrease in malodor scores for the Example 3 stick compared against the control. Two hours after treatment, the difference between the control and Example 3 was directionally significant, and after 4 hours there was essentially no difference between the two products. Nine of the twenty-nine panelists in the study had extremely high mean baseline readings of 7.5 or 8. They were removed from the second series in Table II. With these scores removed, the malodor scores for the Example 3 stick were significantly lower than (improved over) the control at t=0, 2 hours and 4 hours .

TABLE II

Statistical Summary

Within Treatment Changes from Baseline (Before - After)

Between Treatment Changes from Baseline (Before - After)

The foregoing description and Examples illustrate selected embodiments of the present invention. In light thereof variations and modifications will be suggested to one skilled in the art, all of which are within the spirit and purview of this invention.

Claims

1. A lipstick for freshening breath and controlling oral malodor, which lipstick comprises: (i) from about 10 to about 99% of lipophilic material; (ii) from about 0.01 to about 10% by weight of an antibacterial agent; and (iii) from about 0.01 to about 2% of menthol.

2. A lipstick according to claim 1 wherein the antibacterial agent is a zinc salt .

3. A lipstick according to claim 2 wherein the zinc salt is hydrated zinc citrate.

4. A lipstick according to any one of the preceding claims wherein water is present in an amount of from about 0.1 to about 10% by weight.

5. A lipstick according to any one of the preceding claims which further comprises an antioxidant.

6. A lipstick according to any one of the preceding claims wherein at least part of the menthol is in the form of bound menthol.