Eco-friendly non-aqueous antimicrobial composition comprising hinokitiol with 1,3-propanediol and/or sorbitan caprylate
[Problem] The object is to obtain cosmetics which do not show primary skin irritation or sensitization, and do not impart any unpleasant sensation such as sharp pain or prickly sensation when employed as a cosmetic, with the lowest possible inclusion of preservative/fungicide. [Solution] Antimicrobial low-irritant cosmetics characterized in that they contain one or two or more tropolone derivative(s) and one or two or more polyhydric alcohol(s) in quantities which have an anti-microbial effect and low skin irritancy.
1. An eco-friendly, non-aqueous and stable antimicrobial solution composition for a personal care-based end-user composition:
a. consisting of (i) about 0.1 to 3.0 wt % of Hinokitiol; and (ii) 97.0 to 99.9 wt % of 1,3,-propanediol to provide synergistic antimicrobial activity against Escherichia coli and Staphylococcus aureus ; or
b. consisting of (i) about 0.1 to 3.0 wt % of Hinokitiol; and (ii) 97.0 to 99.9 wt % of sorbitan caprylate to provide synergistic antimicrobial activity against Escherichia coli
wherein said personal care-based end-user composition is selected from the group consisting of a shampoo, skin care lotions, bar soaps, baby bath washes, moisturizers, conditioners, in-shower body moisturizers, body washes, shower gels, hair gels, hand soaps, wet wipes, hand sanitizers, creams, sticks, roll-on, sprays, pump-spray, aerosols, powder, solutions, or balms.
2. The antimicrobial composition according to claim 1 , wherein the composition is stable for at least two years at room temperature or stable for at least 5 freeze/thaw cycles when the temperature is cycled 50° C. to −24° C. in every 24 hours or stable for at least 4 weeks at about 50° C.
3. A process for preparing an eco-friendly, non-aqueous and stable antimicrobial solution composition for a personal care-based end-user composition comprising the steps of:
i. preparing a mixture of (a) about 0.1 to 3.0 wt % of Hinokitiol; and (b) about 97.0 to 99.9 wt % of 1, 3-propanediol or sorbitan caprylate; and
ii. heating the mixture of step (i) at about 40° C. to yield a homogenous non-aqueous antimicrobial solution.
4. A method for inhibiting or killing microbial growth comprising mixing an effective amount of antimicrobial composition of claim 1 with a personal care-based end-user composition selected from the group consisting of a shampoo, skin care lotions, bar soaps, baby bath washes, moisturizers, conditioners, in-shower body moisturizers, body washes, shower gels, hair gels, hand soaps, wet wipes, hand sanitizers, creams, sticks, roll-on, sprays, pump-spray, aerosols, powder, solutions, or balms.
5. The method of claim 4 wherein the effective amount of antimicrobial composition is in the range of from about 0.001 wt % to about 25 wt % of the total composition.
6. The method of claim 4 wherein the effective amount of antimicrobial composition is in the range of from about 0.001 wt % to about 5 wt % of the total composition.