ANTIMICROBIAL PERSONAL CLEANSING COMPOSITIONS

Abstract

The invention provides an antimicrobial personal cleansing composition comprising: (i) an aqueous continuous phase including cleansing surfactant, (ii) a dispersed phase including dispersed particles of one or more zinc-containing antimicrobial agents; and (iii) a solubilised oily liquid conditioning agent for skin and/or hair; in which the oily liquid conditioning agent is light mineral oil having a kinematic viscosity of 3 to 5 cS (mm.sup.2.Math.s.sup.−1) at 40° C. and is solubilised in wormlike micelles in the aqueous continuous phase via the incorporation of at least one inorganic electrolyte and at least one linker molecule which is selected from compounds of general formula R(X).sub.n, in which R is an aryl ring having from 6 to 10 carbon atoms or a mono-, di- or trivalent alkyl or hydroxyalkyl chain having from 3 to 14 carbon atoms; n is 1 to 3 and each X is independently selected from —OH, —COOH and —COO.sup.−M.sup.+ groups, where M is an alkali metal, ammonium or alkanolammonium cation; and in which the level of solubilised oily liquid conditioning agent in the conditioning shampoo composition ranges from 0.45 to 3% by weight based on the total weight of the conditioning shampoo composition. The invention also provides the use of the composition described above for the enhanced deposition of one or more zinc-containing antimicrobial agents onto the skin and/or hair.

Claims

1. An antimicrobial personal cleansing composition comprising: (i) an aqueous continuous phase comprising a cleansing surfactant, (ii) a dispersed phase comprising dispersed particles of one or more zinc containing antimicrobial agents; and (iii) a solubilized oily liquid conditioning agent for skin and/or hair; wherein: the solubilized oily liquid conditioning agent is light mineral oil having a kinematic viscosity of 3 to 5 cS (mm.sup.2.Math.s.sup.−1) at 40° C. and is solubilized in wormlike micelles in the aqueous continuous phase via the incorporation of at least one inorganic electrolyte and at least one linker molecule, wherein the at least one linker molecule is selected from compounds of general formula R(X).sub.n, wherein R is an aryl ring having from 6 to 10 carbon atoms or a mono-, di- or trivalent alkyl or hydroxyalkyl chain having from 3 to 14 carbon atoms; n is 1 to 3 and each X is independently selected from —OH, —COOH and —COO.sup.−M.sup.+ groups, where M is an alkali metal, ammonium or alkanolammonium cation; and the level of solubilized oily liquid conditioning agent in the antimicrobial personal care composition ranges from 0.45 to 3% by weight based on the total weight of the antimicrobial personal care composition.

2. The antimicrobial personal care composition according to claim 1, wherein the zinc-containing antimicrobial agent is zinc pyrithione, and the antimicrobial agent is present at a level ranging from 0.25 to 2.5% by weight based on the total weight of the antimicrobial personal care composition.

3. The antimicrobial personal care composition according to claim 1, wherein the level of the light mineral oil ranges from 0.5 to 1.5% by weight based on the total weight of the antimicrobial personal care composition.

4. The antimicrobial personal care composition according to claim 1, wherein R is a phenyl ring or a mono-, di- or trivalent linear alkyl or hydroxyalkyl chain having from 3 to 12 carbon atoms.

5. The antimicrobial personal care composition according to claim 4, wherein the linker molecule is caprylic acid.

6. The antimicrobial personal care composition according to claim 1, wherein the level of the at least one linker molecule ranges from 0.05 to 0.15% by weight based on the total weight of the antimicrobial personal care composition.

7. A method of treating skin and/or hair, the method comprising the steps of: applying the antimicrobial personal cleansing composition according to claim 1 to the skin and/or hair; and rinsing off the skin and/or hair to remove the antimicrobial personal cleansing composition; wherein the method causes deposition of one or more zinc-containing antimicrobial agents onto the skin and/or hair.

8. The antimicrobial personal care composition of claim 1, wherein the solubilized oily liquid condition agent and linker molecule are present in the antimicrobial personal care composition at a weight ratio from about 15:1 to about 1:1.

9. The antimicrobial personal care composition of claim 1, wherein the at least one inorganic electrolyte is a metal chloride or metal sulphate selected from sodium chloride, potassium chloride, calcium chloride, magnesium chloride, zinc chloride, ferric chloride, aluminium chloride, sodium sulphate, magnesium sulphate, or mixtures thereof.

10. The antimicrobial personal care composition of claim 1, wherein the non-volatile silicone is selected from polydimethylsiloxanes, polydimethyl siloxanes having hydroxyl end groups, amino-functional polydimethylsiloxanes, or a mixture thereof.

11. The antimicrobial personal care composition of claim 1, wherein the cleansing surfactant is selected from one or more anionic surfactants.

12. The antimicrobial personal care composition of claim 1, wherein the cleansing surfactant is present at a level from 5% to 26% by weight based on the total weight of the antimicrobial personal care composition.

Description

EXAMPLES

[0106] Hair cleansing shampoo formulations were prepared, having ingredients as shown in Table 1. Examples 1 to 4 represent formulations according to the invention.

TABLE-US-00001 TABLE 1 Control Example 1 Example 2 Example 3 Example 4 Ingredient (% w/w) (% w/w) (% w/w) (% w/w) (% w/w) Sodium laureth sulphate 11.6 11.6 11.6 11.6 11.6 (1EO) Cocamidopropyl betaine 1.5 1.5 1.5 1.5 1.5 Guar hydroxypropyltrimonium 0.2 0.2 0.2 0.2 0.2 chloride Dimethiconol* 1 1 1 1 1 Carbomer 0.4 0.4 0.4 0.4 0.4 Ethylene glycol distearate 0.6 0.6 0.6 0.6 0.6 Mica 0.2 0.2 0.2 0.2 0.2 Disodium EDTA 0.1 0.1 0.1 0.1 0.1 Zinc pyrithione 1 1 1 1 1 Sodium hydroxide 0.2 0.2 0.3 0.3 0.3 Sodium chloride 0.5 2 3 3.6 4.2 Caprylic acid 0 0.05 0.1 0.15 0.2 Lytol ® mineral oil 0 0.45 0.9 1.35 1.8 Water, perfume, preservatives to 100% to 100% to 100% to 100% to 100% *Emulsion of dimethiconol with anionic emulsifier, average particle size < 1 micron (ex Dow Corning)

[0107] Measurement of Zinc Deposition

[0108] The formulations described in Table 1 were assessed for their zinc deposition onto virgin (untreated) hair using the following protocol:

[0109] 0.25 g test formulation is applied to a wet 2.5 g/6″ switch of virgin dark brown European (DBE) hair. The test formulation is massaged on the switch for 30 seconds followed by rinsing with warm water for 30 seconds. This treatment is repeated twice. Zinc deposition is measured by X-ray Fluorescence (XRF). Five replicas were produced for each test formulation. The average of measured zinc deposition is shown in Table 2.

TABLE-US-00002 TABLE 2 Test formulation Exam- Exam- Exam- Exam- Control ple 1 ple 2 ple 3 ple 4 Mean 418 775 709 899 811 deposition/ppm Standard deviation 93 95 114 53 150

[0110] The results show that Examples 1 to 4 (according to the invention) deposit significantly more zinc than the control (not according to the invention). This improved zinc deposition was confirmed as statistically significant by both P value and t-test.

[0111] The formulations described in Table 1 were also assessed for their zinc deposition onto damaged hair using the same test protocol as described above, but instead using wet 2.5 g/6″ switches of double bleached European hair. Again, five replicas were produced for each test formulation. The average of measured zinc deposition is shown in Table 3.

TABLE-US-00003 TABLE 3 Test formulation Exam- Exam- Exam- Exam- Control ple 1 ple 2 ple 3 ple 4 Mean 413 650 576 646 599 deposition/ppm Standard deviation 71 108 124 89 176

[0112] Again the results show that Examples 1 to 4 (according to the invention) deposit significantly more zinc than the control (not according to the invention). This improved zinc deposition was confirmed as statistically significant by both P value and t-test.