AU6386198A - Preservative composition containing tea tree oil (tto) - Google Patents

Description

"PRESERVATIVE COMPOSITION CONTAINING TEA TREE OIL (TTO)" FIELD OF THE INVENTION THIS INVENTION relates to an improved preservative composition containing tea tree oil which can be utilized in a great range of household, industrial or agricultural products inclusive of personal care products, cosmetics, pharmaceuticals, disinfectants, cleaning preparations, paints and other products which contain a preservative or anti-microbial agent to inhibit spoilage or proliferation of micro-organisms. The invention also provides a preservative concentrate which may be incorporated in a vehicle or solvent to form the household, industrial or agricultural product.

BACKGROUND OF THE INVENTION Tea tree oil (TTO) which is obtained from distillation of Melaleuca alternifolia is known as a natural preservative or having antimicrobial properties. For example, reference may be made to Carson et al., 1996, J. Antimicrob. Chemother. 37(6) 1177-1179, which shows that TTO was effective against Streptococci when used topically as a wound disinfectant. Reference also may be made to Raman et al., 1995, Lett. Appl. Microbiol. 21(4) 242-5, which describes the use of TTO and its major components, terpinene-4-ol, alpha terpineol and alpha-pinene, as demonstrating anti-bacterial activity against Staphylococcus aureus, Staphylococcus epidermidis and Propionibacterium acnes

In Carson et al, 1995, J. Appl. Bacteriol. 78(3) 264-9, reference is made to TTO as becoming increasingly popular as a naturally occurring anti-microbial agent. In this reference, it was also shown that terpinene-4-ol, linalool and alpha terpineol were also useful in this regard. In Shapiro et al., 1994, Oral Microbiol. Immunol. 9(4) 202-208, reference is also made to TTO having anti-bacterial activity against fastidiously and facultatively anaerobic oral bacteria.

Reference is also made to Australian Patent 559001 concerning a skin cream containing TTO, a vinyl polymer with carboxyl groups and an alcohol or glycol which is useful for topical administration to skin lesions.

Reference may also be made to Proserpio et al., 1996, Cosmet. Toiletries, Ed. Ital. 17(3) 11-13, 16-19, which refers to TTO having anti-microbial activity in cosmetics and thus being useful as a preservative.

Reference may also be made to an article by Don Priest entitled "Preserving naturally with tea tree oil" published in In-Cosmetics Exhib. Conf. Proc, 1995, 405-411. This reference makes it clear that Melaleuca altemifolia is an Australian native of the Myrtaceae species and is sometimes referred to as "Oil of Melaleuca, Terpinene-4-ol Type" in ISO Standard 4730.

Tea tree oil consists of a mixture of monoterpenes, sesquiterpenes and terpene alcohols. Over 90 chemical components have been isolated from tea tree oil. The anti-microbial activity that has been demonstrated with tea tree oil is mainly due to terpinene-4-ol but other components have activity by themselves or contribute synergistically. The ISO Standard specifies a minimum of 30% terpinene- 4-ol and a maximum of 15% cineole.

At present, the cosmetic, pharmaceutical and personal care products which are currently sold on the market usually have a minimum concentration of 0.5% TTO although, in some cases, the pure product is sold. Such products utilize TTO for its anti-microbial and solvent properties. The range of cosmetic, pharmaceutical and personal care products includes medicated soaps, liquid soaps, deodorants and anti- perspirants, shampoos and conditioners, toothpastes, mouth washes and skin care products inclusive of hand creams, sunscreens and acne preparations. TTO can be supplied as a clear aqueous solution in combination with non-ionic surfactants, such as Polysorbate 20 or Tween 20, referred to in the above Priest reference and disodium edetate which is utilized as a chelating agent. Reference is also made in this publication to a hair conditioner formulation including wheat protein amino acids, panthenol which is a nutritional factor, Vitamin E, PEG-7 glyceryl cocoate or Cetiol which is a solubilizer, Dimethicone which is a skin protectant, citric acid, Vitamin A palmitate, butylene glycol as a humectant, cetostearyl alcohol as an emulsifier, cetyl alcohol as emulsion modifier and cetyltrimethyl ammonium chloride as an antiseptic. Reference is also made in this publication to TTO when used in a moisturising cream which may also include cetyl alcohol, disodium edetate, aloe vera gel, a herbal blend of plant extracts, hydrolysed collagen, propylene glycol, butylene glycol, Vitamin E, Vitamin A palmitate, olive oil, jojoba oil, macadamia nut oil, octyl palmitate, and cetearyl glucoside.

However, while the above reference describes the use of TTO as a natural preservative in a wide range of cosmetics and personal care products at a normal concentration of 0.5% w/v, it is noted that, in the Priest reference, certain formulations which included TTO in percentages greater than 0.5% did not pass the British Pharmacopoeia 1993 Topical (Appendix XVI C), which is the standard of choice in regard to preservative efficacy of pharmaceuticals, cosmetic and personal care products. Reference is also made in the Priest reference to the United States Pharmacopoeia XXII, i.e. USP XXII test, which is also a desired standard in regard to determination of preservative efficacy.

Preservatives, such as TTO, are useful in that they will prevent or limit proliferation of microbial infection in preparations and, in particular, in aqueous preparations. Such preparations may be any pharmaceutical, personal care or cosmetic product. If a preservative is not added to such a product, then microbial contamination could occur and thus present a safety hazard to users of the product or, alternatively, result in spoilage of the product. The efficacy of an anti-microbial preservative may be enhanced or diminished by the active constituent of a pharmaceutical, personal care or cosmetic product or by the formulation of the product or by the container or closure which is used for the product. It is, therefore, necessary to demonstrate that the antimicrobial activity of the product with or without the addition of a preservative provides adequate protection from adverse effects that may occur from microbial contamination or proliferation during storage and use of the product. This is, therefore, the main function of both the USP and BP tests. Both tests comprise challenging the relevant preparation with a prescribed inoculum of suitable micro-organisms, storing the inoculated preparation at a prescribed temperature, withdrawing samples at specified intervals of time and counting the micro-organisms in the samples.

The preservative properties of the preparation are adequate if, in the conditions of the test, there is a significant fall, or no increase, as appropriate, in the number of micro-organisms in the inoculated preparation after the prescribed times and temperatures. The criteria of acceptance, in terms of decrease in the number of micro-organisms with time, vary for different types of preparations. Test organisms usually include Aspergillus niger (ATCC 16404), Candida albicans (ATCC 10231 ), Pseudomonas aeruginosa (ATCC 9027) and Staphylococcus aureus (ATCC 6538). It is recognized that the BP is a far more rigorous test than the USP, requiring, for example, a 3 log reduction of bacteria after 48 hours for topical preparations and a 3 log reduction at 14 days for oral preparations compared to the USP which requires that the number of bacteria be reduced to not more than 0.1 % of the initial concentration after 14 days.

In relation to manufacture of preservatives, it is extremely important to provide a resulting formulation which consistently passes both the USP and the BP preservative efficacy tests. If such is not the case, then it is not only time consuming but extremely costly to vary the percentages of each of the components of a composition to provide a composition which will consistently pass the USP as well as the BP or add other conventional preservatives, such as parabens. Problems can also occur, for example, when the percentages and identity of relevant components of a composition are "juggled" or varied to provide resulting compositions which, while passing the BP and USP, may have deleterious effects in regard to toxicity or safety as well as product stability which sharply increases the commercial risk and safety risk of marketing such compositions.

In regard to conventional TTO preparations, usually the BP and USP tests will be passed if TTO is included in such formulations at a concentration of greater than 2.0%. However, this concentration of TTO in many cases is excessive having regard to the nature of the product as TTO is not only expensive but also has a sharp astringency and strong odour.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a preservative composition containing TTO which will consistently pass the BP preservative efficacy test and thus possess advantages over the prior art discussed above.

The preservative composition of the invention comprises from 0.10-2.0% TTO, from 0.10-2.0% of a phenyl substituted alcohol and optionally at least 10% water together with other components which may include solvents for TTO and phenyl substituted alcohol inclusive of water and polar organic solvents, such as ethanol, methanol, propylene glycol, butylene glycol, ethylene glycol or other polyhydroxy alkanes. Phenyl substituted alcohols include a phenyl group and an alkyl moiety and include within their scope, phenylalkanols and phenoxyalkanols. Phenyl substituted alcohols also dissolve in natural oils, such as olive oil, jojoba oil or macadamia nut oil. Preferred phenyl substituted alcohols include phenylethanol, phenoxyethanol and benzyl alcohol. Benzyl alcohol is the preferred phenyl substituted alcohol for use in the invention.

It will also be appreciated that natural extracts containing a phenyl substituted alcohol may be used in the composition of the invention if the abovementioned range of concentrations is applicable.

The composition may be in any conventional form suitable for use as household, industrial or agricultural product inclusive of a cosmetic, pharmaceutical product, personal care product, disinfectant, paint, cleaning product or other product requiring a preservative or antimicrobial product to inhibit spoilage or proliferation of micro-organisms. When used as a cosmetic or personal care product, the composition may be, for example, in the form of a cream, gel stick, paint, foam, ointment, lotion or spray. The composition may also include additives and excipients conventionally found in topical formulations, such as emulsifiers, surfactants inclusive of ionic, non-ionic and amphoteric surfactants, thickening agents, emollients, stabilizers and humectants.

It is highly desirable, in accordance with the invention, that the composition contains a maximum of 2.0% of both TTO and phenyl substituted alcohol which may be present in equal concentrations of 1.0%. It is even more preferred that the composition contains a maximum of 1.0% of both TTO and phenyl substituted alcohol with, again, TTO and phenyl alcohol being present in equal concentrations of 0.5%. It is also commercially appropriate that the pharmaceutical, personal care or cosmetic composition contains as low an amount of preservative as is possible for reasons of cost as well as market acceptance. TTO, for example, if present in too high a concentration, will provide a distinctive odour and is also relatively expensive. It will be appreciated that TTO may be used in its natural form as well as one or more active components thereof, e.g. terpinen-4-ol and/or alpha terpineol. The term "tea tree oil" as used herein refers to natural forms of TTO which are obtained from any appropriate Melaleuca species or Leptospermum species, such as, for example, M. alternifolia, M. linariifolia, M. dessitafolia as well as modified extracts thereof including the aforementioned active components per se. Benzyl alcohol may be used as it is obtained commercially, such as by the action of sodium or potassium carbonate on benzyl chloride. However, benzyl alcohol may be used as obtained naturally from appropriate sources, such as jasmine, hyacinth, or ylang-ylang oils. The composition of the invention may be used as a clear aqueous solution which may comprise, in addition to TTO and benzyl alcohol, 1-20% surfactant, emulsifier or solubilizing agent. More preferably a non-ionic surfactant such as POLYSORBATE may be utilized. Other suitable surfactants are also described hereinafter. In addition to the aforementioned surfactant, the composition of the invention may include 1-10% of an emollient which moisturizes the skin or, more preferably, 1-5% of the emollient. A suitable emollient is CETIOL or PEG 7 glyceryl cocoate. There also may be included 1-10% and, more preferably, 1-5% of a humectant, such as glycerol or propylene glycol and 1-5% of a thickener or viscosity increasing agent, such as a gum, in the form of a guar gum, gum tregacanth, xanthan gum, or galactomannan gum. There also may be included 1-15% of a detergent, such as sodium lauryl ether sulphate and/or ammonium lauryl sulphate. There also may be provided from 1- 5% of a cleaning agent, such as coconut diethanolamide.

When used as a cream, the composition may include waxes, such as 1-5% of cetyl alcohol or stearyl alcohols.

There also may be included essential oils, herbs, vitamins, such as Vitamin E or Vitamin A, hydrolysed collagen, amino acids, panthenol and other nutritional factors as may be required.

Examples of compositions of the invention when used as a clear aqueous solution, clear liquid soap, moisturizing cream with collagen and herbal extracts, a pearlescent shampoo and a hair conditioner are set out hereinbelow. (A) Clear aqueous solution

0.5% TTO, 0.5% benzyl alcohol, 1.6-3.2% Polysorbate 20 or other suitable non-ionic surfactant, 0.1 % disodium edetate or other suitable chelating agent and 0-5.0% butylene glycol with the balance being purified water.

(B) Clear liquid soap 0.5% TTO, 0.5% benzyl alcohol, 10.0% sodium lauryl ether sulphate 70.0% (Empicol ESB 70), 5.0% ammonium lauryl sulphate 30.0% (Empicol ALS 30), 0.05% disodium edetate, 1.5% cocobetaine (Empigen BB), 1.9% coconut diethanolamide (Empilan FD), 0.20% sodium chloride, citric acid in 10.0% solution to provide a pH of 6.7 and the balance purified water.

(C) Moisturizing cream with collagen and herbal extracts 0.5% TTO, 0.5% benzyl alcohol, 5.0% octyl palmitate, 1.0% olive oil, 4.0% jojoba oil, 1.0% macadamia nut oil, 4.0% cetearyl glucoside (Montanol 68), 0.3% natural Vitamin E (Covitol F1300), 0.075% Vitamin A palmitate, 2.0% butylene glycol, 5.0% propylene glycol, 1.0% hydrolysed collagen (Crotein A), 1.0% herbal blend (equal parts of extracts of cernica, marshmallow, cucumber, elder flower, witch hazel and lime blossom), 10.0% aloe vera gel, 0.1 % disodium edetate, perfume 0.35% and the balance purified water having a pH of 5.1. (D) Pearlescent shampoo

0.5% TTO, 0.5% benzyl alcohol, 10% sodium lauryl ether sulphate, 0.05% disodium edetate, 3.0% cocobetaine, 3.0% coconut diethanolamide (Empilan FD), 0.10% Polyquaternium 10 (Polymer JR- 400), 3.0% pearling agent (Euperlan PK771), 0.20% sodium chloride, citric acid (10.0%) to make up a pH of 6.5 with the balance being purified water. (E) Hair conditioner

0.5% TTO, 0.5% benzyl alcohol, 3.0% cetostearyl alcohol, 0.15% Dimethicone Vitamin E Natural (Covitol F1300), 0.05% PEG-7 glyceryl cocoate (Cetiol HE), 1.0% wheat protein amino acids (Hydrotriticum WAA), 0.10% citric acid (10.0%), 0.10% panthenol and 1.0% cetyltrimethyl ammonium chloride 50.0% (Dehyquart A) with the balance being purified water.

In another aspect of the invention, there is provided a preservative concentrate comprising:- (i) 20-80% TTO;

(ii) 20-80% phenyl substituted alcohol;

(iii) 0-80% surfactant; and

(iv) 0-80% dispersing agent.

Preferably in the concentrate, there is provided 25-80% surfactant and 20-80% dispersing agent. More preferably, there is provided 35-45% surfactant and 20-50% dispersing agent.

Preferably the concentrate comprises 30-50% TTO and 30- 50% phenyl substituted alcohol. Most preferably the TTO and phenyl substituted alcohol may be present in equal concentrations such as 40%. The surfactant may be an anionic surfactant, such as a carboxylate, sulfonate, sulfated alcohol or sulfated alcohol ethoxylate. Cationic and amphoteric surfactants may also be used but the preferred surfactant is a non-ionic surfactant, such as polyoxyethylene surfactant or carboxylic acid esters, such as glycerol esters, polyoxyethylene esters, anhydrosorbitol esters, natural fats, oils and waxes and ethoxylated and glycol esters of fatty acids.

Preferred surfactants are marketed under the trade marks ETOCAS or CREMOPHOR.

The function of the dispersing agent is to facilitate dispersion of the TTO in the concentrate. Without the dispersing agent, it would be necessary to mix TTO very slowly with water together with the phenyl substituted alcohol which necessitates the concentrate forming a gel. The use of the dispersing agent may also provide a clear solution of concentrate. A preferred dispersing agent is propylene glycol although it will be appreciated that any other polyhydroxy alcohol could be used, such as glycerol, sorbitol or polyethylene glycol. Other alcohols may also be utilized, such as methanol, ethanol or isopropanol.

A preferred form of concentrate is provided in water soluble form which includes 0.5 g TTO, 0.5 g benzyl alcohol, 1.0 g surfactant and 0.5 g propylene glycol. In this preferred form, the resulting 2.5 g concentrate may be dissolved in 100 g of vehicle or diluent.

In another embodiment, the concentrate may comprise 0.5 g

TTO, 0.5 g benzyl alcohol and 1.0 g propylene glycol. In this embodiment, there is provided 2.0 g of concentrate which may be dissolved in 100 g of vehicle or diluent. Such a concentrate may be utilized for non-aqueous vehicles or solvents.

An example of a concentrate produced in accordance with the invention comprises 20% TTO, 20% benzyl alcohol, 35-40% Etocas 35, (i.e. Polyoxyl 35 castor oil) which is used as a surfactant and 20% propylene glycol. This corresponds to 0.5 g benzyl alcohol, 0.5 g TTO, 1.0 g Etocas and 0.5 g propylene glycol. This concentrate was used in the following products:-

(F) Typical Cream

10% Emulgade 1000 Nl, which is a colloid disperse mixture of cetyl stearyl alcohol with non-ionic emulsifiers on the basis of saturated fatty polyglycol esters, 5% arachis oil, 2.5% glycerol and 2.5% preservative concentrate with the balance being purified water.

(G) Typical Lotion

15% glycerol monosterate A-S, 3% Emulgin B1 (cetyl stearyl alcohol with approximately 12 mol ethylene oxide as non-ionic emulsifier), 5% glycerol, 2% cetyl alcohol, 2.5 preservative concentrate with the balance being purified water. (H) Typical Gel Formulation

3% Sepigel 305 (isoparaffin dispersion of a polyacrylamide- water solution), 2.5% preservative concentrate, 5% glycerol with the balance being purified water.

(I) Typical Conditioner 2% cetyl alcohol, 3% cetostearyl alcohol, 3% Vantoc CC (cetyl trimethylammonium chloride), 5% CroquotL 5% (lauryldimonium hydroxypropyl hydrolyzed collagen), DiPanthenol 0.5%, preservative concentrate 2.5% with the balance being purified water. The steps associated in preparation of the conditioner involved heating cetyl alcohol and cetostearyl alcohol to 70°C. Vantoc CC is dissolved in water and heated to 70°C. The two solutions are added together and stirred and cooled to 40°C at which time CroquotL is added and mixed. The mixture is cooled to 35°C and the DiPanthenol is added with the preservative concentrate. The conditioner is then stirred until cold.

EXPERIMENTAL Determination of BP Preservative Efficacy Test Test Organisms (i) Aspergillus niger \M\ 149 007 (ATCC 16404, IP 1431.83);

(ii) Candida albicans NCPF 3179 (ATCC 10231 , IP 48.72); (iii) Pseudomonas aeruginosa NCIMB 8626 (ATCC 9027, CIP

82.118); (iv) Staphylococcus aureus NCTC 10788 (NCIMB 9518, ATCC 6538, CIP 4.83).

Preparation of inoculum

Preparatory to the test, inoculate the surface of a tryptone soya agar plate for bacteria or Sabouraud agar plate for fungi, with the recently grown stock culture of each of the specified micro-organisms. Incubate the bacterial cultures at 30-35° for 18-24 hours, the culture of Candida albicans at 20-25° for 48 hours, and the culture of Aspergillus niger at 20-25° for 7 days or until good sporulation is obtained. Subcultures may be needed after revival before the organism is in its optimal state, but it is recommended that the number of sub-cultures be kept to a minimum.

To harvest the bacterial and Candida albicans cultures, use a sterile suspending fluid containing 0.9% w/v of sodium chloride and 0.1 % of peptone for dispersal and transfer of the surface growth into a suitable vessel. Add sufficient suspending fluid to reduce the microbial count to about 10⁸ micro-organisms per ml. To harvest the Aspergillus niger culture, use a sterile suspending fluid containing 0.9% w/v of sodium chloride and 0.05% w/v of Polysorbate 80 and adjust the spore count to about 10⁸ per ml by adding the same solution.

Remove immediately a suitable sample from each suspension and determine the number of colony-forming units per ml in each suspension by plate count or by membrane filtration. This value serves to determine the inoculum and the baseline to use in the test. The suspension shall be used immediately. Test procedure

To count the viable micro-organisms in the inoculated products, use the agar medium used for the initial cultivation of the respective micro-organisms.

Inoculate a series of containers of the products to be examined, each with a suspension of one of the test organisms to give an inoculum of 10⁵ to 10⁶ micro-organisms per g or per ml of the preparation. The volume of the suspension of inoculum does not exceed 1 % of the volume of the product. Mix thoroughly to ensure homogeneous distribution.

Maintain the inoculated product at 20-25°C, protected from light. Remove a suitable sample from each container, typically 1-ml or 1-g quantities, at zero hour and at appropriate intervals according to the type of the product and determine the number of viable micro-organisms by plate count or membrane filtration. Ensure that any residual anti-microbial activity of the product is eliminated by dilution, by filtration or by the use of a specific inactivator. When dilution procedures are used, due allowance is made for the reduced sensitivity in the recovery of small numbers of viable micro-organisms. When a specific inactivator is used, the ability of the system to support the growth of the test organisms is confirmed by the use of appropriate controls.

The USP preservative efficacy test is carried out by a similar procedure as described above in relation to the BP preservative efficacy test.

However, the criteria for acceptance in regard to both the BP and the USP are different. In the BP, for an inoculum of 10⁵-10⁶ bacteria per g or per ml of preparation having regard to topical preparations, for such preparations to pass the BP they must demonstrate a 3 log reduction at 48 hours and no recovery at 7, 14 and 28 days. For an inoculum of 10⁵-10⁶ fungi per g or per ml of preparation, the topical preparation being tested must demonstrate a 2 log reduction at 14 days and no recovery at 28 days. The above criteria (otherwise known as Criteria A) express the recommended efficacy to be achieved. In relation to oral preparations, in relation to an inoculum of

10⁵-10⁶ bacteria, there must be shown a 3 log reduction at 14 days and no increase at 28 days. For inoculums having 10⁵-10⁶ fungi, there must be demonstrated a 1 log reduction at 14 days and no increase at 28 days.

In relation to the USP, by comparison, preparations to pass the USP must show (i) a reduction in growth in relation to bacteria at not more than 0.1 % of initial concentrations after 14 days and (ii) in relation to fungi, there must be shown that during the first 14 days, the concentration must remain at or below the initial concentration. In these situations, it is also necessary to demonstrate the concentrations of each test organism must remain at or below the levels referred to in (i) and (ii) above for the rest of a 28 day test period.

Hence, from the foregoing, it can be demonstrated that the BP test is far more severe than the USP test.

EXAMPLES Example 1

A preparation containing 0.2% benzyl alcohol, 0.5% TTO, Etocas 35 1.0%, propylene glycol 0.5% and the remainder being water, was tested in relation to both the BP and the USP with the result being shown in TABLE 1. This preparation did not pass either the BP or USP as indicated. Example 2

A similar preparation was made as described in Example 1 with the concentration of benzyl alcohol being increased to 0.5%. The results are shown in TABLE 2 and it will be noted that this preparation passed both the BP and the USP. Example 3

A similar preparation was made as described in Example 1 with the concentration of TTO being decreased to 0.3%. The results are shown in TABLE 3 and it will be noted that this preparation did not pass either the BP or USP. Example 4

A similar preparation was made as described in Example 1 with the exception that the concentration of benzyl alcohol was increased to 0.5% and the concentration of TTO was decreased to 0.3%. The results are shown in TABLE 4 and it will be noted that this preparation passed both the BP and USP.

Example 5 A similar preparation was made as described in Example 1 with the exception that TTO was omitted and benzyl alcohol included in a concentration of 0.5%. The results are shown in TABLE 5 and it will be noted that this preparation did not pass either the BP and USP.

Example 6

A similar preparation was made as described in Example 1 with the exception that benzyl alcohol was omitted and TTO had a concentration of 0.3%. The results are shown in TABLE 6 and it will be noted that this preparation did not pass the BP for topical preparations.

More specifically, the fungal counts were not reduced by a factor of 10² within 14 days.

Example 7

A similar preparation was made as described in Example 1 with the exception that benzyl alcohol was omitted and TTO had a concentration of 0.5%. The results are shown in TABLE 7 and it will be noted that this preparation did not pass both the BP for topical preparations because the Aspergillus niger count was not reduced by a factor of 10² within 14 days.

Example 8 A preparation comprising 0.3% TTO in aqueous solution with 1.0% Etocas 35 was tested in relation to both the BP and USP. It will be noted in TABLE 8 that this preparation did not pass either the BP and USP and, in particular, was relatively inactive against Pseudomonas aeruginosa and Aspergillus niger. Example 9

A preparation comprising 0.2% benzyl alcohol, 1 % Etocas 35, 0.5% propylene glycol and the remainder being water, was prepared and tested in relation to the BP topical criteria having regard to Aspergillus niger alone. The results are shown in TABLE 9 and it will be noted that this preparation did not pass the BP. The preparation was also tested in regard to the USP having regard to Aspergillus niger alone and the results are shown in TABLE 10. It will be noted that this preparation did not pass the USP.

Example 10 The preparation of Example 9 was modified to increase the benzyl alcohol concentration alone to 0.5% and tested in relation to the BP in relation to having regard to Aspergillus niger alone. It is noted in TABLE 11 that there was a marked improvement in effectiveness against Aspergillus niger and thus this preparation passed the BP. Example 11

Example 10 was repeated in its entirety and tested against the USP criteria and the results shown in TABLE 12 show that similar results were obtained to those in Example 10.

Example 12 The preparation of Example 9 was modified so as to have a concentration of 1.0% of benzyl alcohol and tested against both the BP topical criteria in relation to Aspergillus niger alone and the USP criteria. These results are shown in TABLES 13 and 14 respectively and indicate that benzyl alcohol has a strong inhibitory effect on growth of Aspergillus niger. Example 13

A preparation containing 0.2% phenoxyethanol, 0.5% TTO and 1.0% Etocas 35 and the remainder being water, was tested in relation to both the BP topical and USP criteria. These results are shown in

TABLE 15 and it will be noted that this preparation passed the requirements of the BP (criteria A) and USP.

Example 14 A similar preparation was made as described in Example 13 with the concentration of phenoxyethanol being increased to 0.5%. The results shown in TABLE 16 indicate that this preparation passed both the BP (criteria A) and the USP.

Example 15

A similar preparation was made as described in Example 13 with the exception that the concentration of TTO was reduced to 0.3%.

The results shown in TABLE 17 indicate that the preparation meets the requirements of the BP (criteria B) for Aspergillus niger and meets the requirements of the USP.

Example 16

A similar preparation was made as described in Example 13 with the exception that the concentration of phenyoxyethanol was increased to 0.5% and TTO was decreased to 0.3%. The results as shown in TABLE 18 indicate that the preparation meets the requirements of the BP (criteria A) and the USP.

Example 17

A similar preparation was made as described as in Example

13 with the exception that phenoxyethanol was increased to 0.5% and TTO was omitted. The results are as shown in TABLE 19 indicate that the preparation did not pass the requirements of the BP but did pass the requirements of the USP.

Example 18 A similar preparation was made as described in Example 13 with the exception that phenyoxyethanol was increased to 1.0% and TTO was omitted. The results as shown in TABLE 20 indicate that the preparation passed the requirements of the BP (criteria A) and the USP.

Example 19

A similar preparation was made as described in Example 13 with the exception that phenyoxyethanol was increased to 0.5% and TTO and Etocas 35 were omitted. The results as shown in TABLE 21 indicate that the preparation failed the requirements of the BP and passed the requirements of the USP.

Example 20 A similar preparation was made as described in Example 13 with the exception that phenyoxyethanol was increased to 1.0% and TTO and Etocas 35 were omitted. The results as shown in TABLE 22 indicate that the preparation passed both the requirements of BP (criteria A) and the USP. Example 21

A preparation containing 0.2% phenyoxyethanol, 0.5% TTO,

1.0% Etocas 35 and 0.5% propylene glycol and the remainder being water, was tested in relation to both BP and the USP with the result being shown in TABLE 23. This preparation did not pass either the requirements of the BP or the USP for Aspergillus niger.

Example 22 A similar preparation was made as described in Example 21 with the exception that phenoxyethanol was increased to 0.5%. The results as shown in TABLE 24 indicate that the preparation passed both the requirements of the BP and the USP. Example 23

A similar preparation was made as described in Example 21 with the exception that TTO was reduced to 0.3%. The results as shown in TABLE 25 indicate that the preparation did not pass the requirements of the BP and the USP for Aspergillus niger. Example 24

A similar preparation was made as described in Example 21 with the exception that phenoxyethylene was increased to 0.5% and TTO was decreased to 0.3%. The results as shown in TABLE 26 indicate that the preparation passed both the requirements of the BP and the USP. Example 25

A similar preparation was made as described in Example 21 with the exception that phenoxyethanol was increased to 0.5% and TTO was omitted. The results as shown in TABLE 27 indicate that the preparation failed both the requirements of the BP and the USP. Example 26

A similar preparation was made as described in Example 21 with the exception that phenoxyethanol was increased to 1.0% and TTO was omitted. The results as shown in TABLE 28 indicate that the preparation passed both the requirements of the BP and the USP. Example 27

A similar preparation was made as described in Example 21 with the exception that phenoxyethanol was increased to 0.5% and TTO and Etocas 35 were omitted. The results as shown in TABLE 29 indicate that the preparation passed both the requirements of the BP and the USP. Example 28

A similar preparation was made as described in Example 27 with the exception that phenoxyethanol was increased to 1.0%. The results as shown in TABLE 30 indicate that the preparation passed both the requirements of the BP and the USP.

CONCLUSIONS It will be noted from the above Examples that the preferred preservatives of the composition contain at least 0.3% TTO and 0.5% benzyl alcohol. It is also noted that benzyl alcohol is more inhibitory towards growth of Aspergillus niger which is relatively unaffected by TTO. TTO, on the other hand, is more effective against bacteria, including Pseudomonas aeruginosa, which is relatively unaffected by benzyl alcohol.

TABLES

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6 All results expressed as cfu/g

TABLE 7 All results expressed as cfu/g

TABLE 8 All results expressed as cfu/g

TABLE 9 All results expressed as cfu/g

TABLE 10 All results expressed as cfu/g

TABLE 11 All results expressed as cfu/g

TABLE 12 All results expressed as cfu/g

TABLE 13 All results expressed as cfu/g

TABLE 14 All results expressed as cfu/g

TABLE 15

TABLE 16

TABLE 17

TABLE 18

TABLE 19

TABLE 20

TABLE 21

TABLE 22

TABLE 23

TABLE 24

TABLE 25

TABLE 26

TABLE 27

TABLE 28

TABLE 29

TABLE 30

Claims (28)

1. A preservative composition including:- (i) 0.10-2.0% tea tree oil;

(ii) 0.10-2.0% phenyl substituted alcohol; and (iii) one or more solvents for the tea tree oil and the phenyl substituted alcohol.

2. A preservative composition as claimed in Claim 1 further including one solvent for tea tree oil and phenyl substituted alcohol.

3. A preservative composition as claimed in Claim 2 wherein the solvent is water.

4. A preservative composition as claimed in Claim 2 wherein the solvent is at least one polar organic solvent.

5. A preservative composition as claimed in Claim 4 wherein the solvent is at least one of ethanol, methanol, propylene glycol, butylene glycol, ethylene glycol or other polyhydroxy alkane.

6. A preservative composition as claimed in Claim 2 wherein the solvent is a natural oil.

7. A preservative composition as claimed in Claim 6 wherein the natural oil is olive oil.

8. A preservative composition as claimed in Claim 6 wherein the natural oil is jojoba oil.

9. A preservative composition as claimed in Claim 6 wherein the natural oil is macadamia nut oil.

10. A preservative composition as claimed in any preceding claim wherein the phenyl substituted alcohol is benzyl alcohol.

11. A preservative composition as claimed in any of Claims 1 to 9 wherein the phenyl substituted alcohol is phenylethanol

12. A preservative composition as claimed in any of Claims 1 to 9 wherein the phenyl substituted alcohol is phenoxyethanol. .

13. A preservative composition as claimed in any preceding claim wherein the phenyl substituted alcohol is in a natural extract.

14. A preservative composition as claimed in any preceding claim wherein the concentrations of TTO and phenyl substituted alcohol are equal.

15. A preservative composition as claimed in any of Claims 1 to 13 wherein TTO and the phenyl alcohol are present in a combined concentration of 1 % w/v.

16. A preservative composition as claimed in Claim 14 wherein TTO is present in a concentration of 0.5% w/v and the phenyl alcohol is present in a concentration of 0.5% w/v.

17. A preservative composition as claimed in Claim 17 wherein

TTO is present in a concentration of 0.5% w/v and the phenyl alcohol is present in a concentration of 0.5% w/v.

18. A preservative composition as claimed in any preceding claim having at least 10% water.

19. A preservative concentrate comprising:-

(i) 20-80% tea tree oil; (ii) 20-80% phenyl substituted alcohol; (iii) 0-80% surfactant; and (iv) 0-80% dispersing agent.

20. A preservative concentrate as claimed in Claim 19 comprising 25-80% surfactant and 20-80% dispersing agent.

21. A preservative concentrate as claimed in Claim 19 comprising 30-50% TTO and 30-50% phenyl substituted alcohol.

22. A preservative concentrate as claimed in Claim 19 comprising 40% TTO and 40% phenyl substituted alcohol.

23. A preservative concentrate as claimed in Claim 19 wherein the phenyl substituted alcohol is selected from the group consisting of benzyl alcohol, phenoxyethanol and phenylethanol.

24. A preservative concentrate as claimed in Claim 23 wherein the phenyl substituted alcohol is benzyl alcohol.

25. A preservative concentrate as claimed in Claim 19 wherein the surfactant is a non-ionic surfactant.

26. A preservative concentrate as claimed in Claim 25 wherein the non-ionic surfactant is a polyoxyethylene surfactant.

27. A preservative concentrate as claimed in Claim 19 wherein the dispersing agent is a polyhydroxy alcohol.

28. A preservative concentrate as claimed in Claim 19 wherein the dispersing agent is propylene glycol.