AU2011203303A1 - Protectant against External Parasitic Infestation - Google Patents

Abstract

The invention relates to the prevention of lice infestations by applying a product containing the component 3,7-dimethyl-6-octenoic acid (more commonly known as Citronellic Acid) as a single active constituent or in combination with other already known active components.

Description

- 1 Protectant against External Parasitic Infestation The invention relates to the prevention of lice infestations by applying a product containing the component 3,7-dimethyl-6-octenoic acid (more commonly known as Citronellic Acid) as a single active constituent or in combination with other already known active components. Background Lice infestation in humans has been recognised as a problem for thousands of years. It was thought that lice were generated spontaneously from dirt, sweat or other diseases. It was not until the invention of the microscope that the true nature of the parasite was revealed. In man three varieties of lice commonly occur. Headlice (Pediculus humanus capitis), bodylice (Pediculus humanus humanus) and pubic lice (Pthirus pubis). Each parasite has a preference for different parts of the skin. The itch associated with lice infestation is due to the injection into people of compounds once the lice have penetrated the skin. Headlice are transmitted by direct physical contact and thus are rapidly transmitted in a school playground or classroom or in a family situation where members are in close contact. The act of combing the hair is another activity associated with headlice transmission as lice can be propelled large distances by static electricity during brushing or combing. Fleas are parasites that spend much of their lives away from their hosts eg in the carpet. Fleas can be contacted from animals and inanimate surfaces, such as carpet, to humans. Fleas commonly infect cats and dogs. In particular, species such as Ctenocephalides felis and Ctenocephalides canis are implicated. Ticks are also blood feeding parasites. Ticks cause paralysis and are vectors of microbes that cause diseases like typhus and Lyme disease. The tick genus Ixodes is the best known. The most economically and medically significant species of Ixodes ticks are Ixodes scapularis, Ixodes ricinus and Ixodes persulcatus. Related Art US 5,411,992 U.S. Patent 5,696,158 W.O. 9707677 U.S. Patent 6,34225 Mumcuoglu, KY et al Repellency of citronella for head lice: double-blind randomized trial of efficacy and safety.lsr Med Assoc J.2004 Dec;6(12):756-9. Nutanson, I. et al Pediculus humanus capitis: an update., Acta Dermatoven APA Vol 17, 2008,4. Repellancy from external parasite is discriminated in the art. Several commercially available products utilise the same or similar ingredient/s which have been used in treatment products for already existing parasitic infections.

-2 An example is Neem Oil (Azadirachta indica, well known in Ayurvedic medicine. Other examples propose claims based on the use of well known insect repellant ingredients such as Piperonal (U.S. Patent 5,696,158 1997), essential oils (U.S. Patent 6,342253 2002) and Terpenoids ( US 5411992 1995, W.O. 9707677 1997 and Mumcuoglu. Nutanson, (2008) Reports that the application of natural essential oils and terpenoid chemistry is established in the art. Description of the Invention According to a first aspect, the invention provides an enduring means of preventing external parasitic infestation by applying a product containing as a single active constituent or in combination with other already known active components. By enduring, it is meant that the product is efficacious for a period of at least eight (8) hours. Essential oils and their components are typically volatile. Citronellic acid is stable, relatively non-volatile and persistent on both human skin and inanimate surfaces. It has a low odour, thus enhancing likely compliance in use. The single active constituent is a monoterpenoid carboxylic acid formed by the oxidation of citronellal with the chemical name is 3,7-dimethyl-6-octenoic acid (more commonly known as citronellic acid). Citronellic Acid may be present at an amount of up to 5% w/w, and more preferably present in an amount in the range of 0.05% w/w to 0.5% w/w. The external parasitic protectant may be formulated in any known carrier system. Preferably, the repellents are formulated as gels, creams (two phase systems), lotions (thinned creams or aqueous alcohols) or spray on formulations (usually alcohol based). Those skilled in the art will appreciate that while some forms of base are preferred, a wide variety of known standard generic and proprietary carriers may be used without departing from the concept of the present invention. It will be appreciated by those skilled in the art that numerous other excipients such as emulsifiers, solubilizers, emollients, thickeners, film forming agents, surfactant, chelating agents, antioxidants, preservatives and fragrances may be incorporated into the carrier system as appropriate. Additionally, other active external parasitic repellant substances, already known in the art, may be incorporated into combinations with the citronellic acid component. The following are examples of various alcoholic and hydroalcoholic embodiments that would be suitable as sprayable products. Each of these has been evaluated for in-vitro efficacy against lice.

-.3 EXAMPLE 1 %w/w Ethanol 95% PG F2 79.3 Citronellic Acid 0.5 Diisopropyl Adipate 15.0 Trimethyl pentanediol/adipic acid/ glycerin crosspolymer 5.0 Tocopherol 0.2 EXAMPLE 2 %w/w Ethanol 95% PG F2 79.55 Citronellic Acid 0.25 Diisopropyl Adipate 15.00 Trimethyl pentanediol/adipic acid/ glycerin crosspolymer 5.00 Tocopherol 0.20 EXAMPLE 3 %w/w Ethanol 95% PG F2 79.7 Citronellic Acid 0.1 Diisopropyl Adipate 15.0 Trimethyl pentanediol/adipic acid/ glycerin crosspolymer 5.0 Tocopherol 0.2 EXAMPLE 4 %w/w PVP K-90 2.00 Disodium edetate 0.10 Ethanol 15.00 Citronellic acid 0.25 PEG-40 Hydrogenated Castor Oil 0.75 Propyl Gallate 0.05 Preservative 1.00 Purified water q.s. to 100.00 -4 BEST MODES FOR CARRYING OUT THE INVENTION In-vitro Lice testing: General Protocol The efficacy of the invention as a head lice protectant is demonstrated by measuring its repellency in an in-vitro test situation. The general protocol for determining Head Lice repellency in-vitro is as follows: One half of a filter paper (e.g. Whatman no.4) is treated with 0.1 ml of test solution, while the other half is left untreated. The treated filter paper is then placed on a petri dish. Ten (10) lice are then placed in the centre of the petri dish and the dish is covered and placed in the dark. The treated product is then allowed to dry for 30 minutes at 20'C. It is then held at 37oC for the appropriate test period, usually 2, 4 or 8 hours. Two (2) hours after initial treatment, ten (10) lice are introduced to the centre of the dish. The numbers of lice that have migrated to the treated half, and the number that have migrated to the untreated half are recorded. This is repeated with a fresh batch of ten (10) lice four (4) and eight (8) hours after initial treatment. The degree of repellency is expressed by: % repellency = (1-T/C) x 100, where T is the number of lice on the treated half, and C is the number of lice on the untreated, or control half. In a variant of the above method, a cloth of a material and colour attractive to lice is placed on the treated half of a filter paper prepared as described above. The numbers of lice on the treated half, untreated half and on the cloth are recorded at each time point. In each test method, five (5) replicates of ten (10) lice are used at each time point, for a total of fifty (50) lice. In each of these cases, the test species is the Body Louse, or Clothing Louse (Pediculus humanus humanus). It is much easier to breed and maintain colonies of this species in a laboratory environment, than Head Lice (Pediculus humanus capitis), which is the species usually responsible for infestations in human populations. These are variations of the method described in US Patent 5,411,992 Eini et. al. "Lice repellant Composition" May 2, 1995. TEST RESULTS A number of example formulations described above were tested according to the in-vitro test methods also described above.

-5 The test results described in Tables 1-3 were obtained via the half treated filter paper method. The results are expressed in percentage terms. Table 1: Test Results for Formula of Example 3. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 4 8 8 Lice on untreated half 96 92 92 % repellency 95.8 91.3 91.3 Table 2: Test Results for Formula of Example 3. where Citronellic Acid has been omitted. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 36 28 38 Lice on untreated half 64 72 62 % repellency '43.8 61.1 38.7 The drop in repellency observed here confirms the effect of the citronellic acid on lice repellency. Table 3: Test results where a water control only was tested. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 78 56 60 Lice on untreated half 22 44 40 % repellency 0 0 0 The absence of repellency in the water control confirms the viability of the lice used in this series of tests.

-6 The test results described in Tables 4-8 were obtained via the half treated filter paper method where an old piece of cloth was placed on the treated half of the filter paper. Table 4: Test Results for Formula of Example 1. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 0 0 0 Lice on untreated half 86 86 76 Lice on cloth 14 14 24 % repellency 100.0 100.0 100.0 Table 5: Test Results for Formula of Example 2. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 0 0 0 Lice on untreated half 92 88 68 Lice on cloth 8 12 32 % repellency 100.0 100.0 100.0 Table 6: Test Results for Formula of Example 3. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 0 0 0 Lice on untreated half 18 10 30 Lice on cloth 82 90 70 % repellency 100.0 100.0 100.0 Table 7: Test Results of Formula of Example 4. Time after Treatment 2 Hours 4 Hours 8 Hours Lice on treated half 0 0 0 Lice on untreated half 52 76 58 Lice on cloth 48 24 42 % repellency 100.0 100.0 100.0 Table 8: Test results where a water only control was tested. Time after Treatment 2 Hours 4 Hours 8 Hours -7 Lice on treated half 6 12 16 Lice on untreated half 4 4 2 Lice on cloth 90 84 82 % repellency 0 0 10 While the formulations appear to be effective as lice repellents, it is worth noting that the lice involved in this series of test have a third option, other than the treated or untreated surfaces of the filter paper. Where lice are forced to make a choice between treated and untreated surfaces, as shown in Tables 1-3, the effectiveness of the invention as a head lice repellent is more clearly demonstrated.

Claims (9)

1. An enduring external parasitic repellent composition consisting of the active component 3,7-dimethyl-6-octenoic acid (more commonly known as Citronellic Acid) component alone or in combination.

2. A composition according to Claim 1 where the efficacy is maintained for a period of at least eight hours when tested in-vitro against the Body louse species Pediculus humanus humanus.

3. A composition according to Claim 1, where the said essential oil component is a monoterpenoid carboxylic acid.

4. A composition according to any one of the preceding claims, where the said component is a monoterpenoid carboxylic acid formed by the oxidation of citronellal or related compounds.

5. A composition according to any one of the preceding claims, where the said component is is 3,7-dimethyl-6-octenoic acid (more commonly known as citronellic acid).

6. A composition according to any one of the preceding claims where the said component is present at any level up to 5% w/w.

7. A composition according to any one of the preceding claims where the said component is present in a formulation at a level of 0.05 to 0.5 % w/w.

8. A composition according to any one of the preceding claims where the composition may be formulated as gels, creams (two phase systems), lotions (thinned creams or aqueous alcohols) or spray on formulations (usually alcohol based, aqueous based or a combination thereof).

9. A composition according to any one of the preceding claims where any excipients such as emulsifiers, solubilizers, emollients, thickeners, film forming agents,surfactants, chelating agents, antioxidants, preservatives and fragrances may be incorporated.