Emulsions with naphthalate esters

Details Emulsions with naphthalate esters Emulsions with naphthalate esters

2000-05-19

2002-10-22

Dees, Jose′ G. (Department: 1616)

Drug, bio-affecting and body treating compositions

Anti-perspirants or perspiration deodorants

C424S401000

Reexamination Certificate

active

06468511

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to cosmetic product, especially antiperspirant and/or deodorant products which contain an antiperspirant active ingredient and which provides better efficacy and stability without compromising aesthetics. The compositions are emulsions made with an external (or oil) phase and an internal phase which contains the active ingredient. These emulsions may be used to form gel, soft solid or roll-on products.
BACKGROUND OF THE INVENTION
A large variety of antiperspirant and/or deodorant formulations have been described in the patent literature and/or have been made commercially available. These products have included suspension as well as emulsions. Also various physical forms may be used such as solids (for example, wax and gel sticks), semi-solids (for example, gels and creams), liquids (for example, roll-on products) and sprays (both aerosol and non-aerosol).
In recent years a strong emphasis has been placed on improving both the performance of antiperspirant and/or deodorants, for example, the efficacy, aesthetics, and stability of these products. One of the particular problems is trying to obtain an emulsion product that has efficacy comparable to suspension products. A second problem is the stabilization of emulsion products to achieve a product that is shelf stable, but which releases an active ingredient in a timely manner. These problems have been caused, in part, by the use of non-volatile silicones used to match the refractive index of the two phases for clear systems or used for improving skin feel. The use of such non-volatile silicones (1) decreases the ability of the active ingredient to be released from the composition thereby decreasing efficacy, and (2) makes the emulsions so stable that the active is not released in a timely manner.
With regard to emulsions, U.S. Pat. No. 4,673,570 to Soldati describes uniform, clear gelled antiperspirant compositions, free of waxes wherein the emulsions comprise in combination a volatile silicone fluid, a silicone emulsifier (such as a mixture of cyclomethicone and dimethicone copolyol), a destabilizing auxiliary emulsifier, water, a non-volatile emollient (such as C10-C20 alkyl fatty esters and ethers), linear silicone fluids, a coupling agent (such as low molecular weight alcohols and glycols), an active antiperspirant component and other ancillary agents.
U.S. Pat. No. 5,008,103 to Raleigh et al describes water-in-oil antiperspirant emulsions having a discontinuous polar phase containing water and optionally containing an emulsifier with a hydrophilic-lipophilic balance (HLB value) greater than 8, and a volatile silicone continuous phase with a dimethicone copolyol emulsifier. The HLB parameter is a well known parameter the calculation of which is disclosed and explained in numerous references. For nonionic surfactants, data obtained by actual analysis is usually a more accurate measure of HLB values (rather than theoretical determinations). U.S. Pat. No. 5,401,870 to Raleigh et al and U.S. Pat. No. to 5,292,503 to Pereira et al describe similar subject matter.
U.S. Pat. No. 5,216,033 to Pereira et al describes a transparent water-in-oil emulsion containing a silicone phase with a dimethicone copolyol and an aqueous phase containing a refractive index “transparency structurant” to produce a refractive index matched clear emulsion. The transparency structurant is a C3-C8 polyhydric alcohol.
U.S. Pat. No. 5,599,533 to Stepniewski et al describes the use of silicone elastomer in an aqueous water-in-oil emulsion, but does not describe a clear emulsion.
U.S. Pat. No. 5,989,531 describes a liquid composition made with (a) an active phase comprising a selected glycol, a nonionic emulsifier having an HLB value greater than 8 and an antiperspirant and/or deodorant active; and (b) a silicone phase made with one or more of a dimethicone copolyols having an HLB less than 7 and nonionic emulsifiers having an HLB greater than 7, wherein the silicone phase has at least 10% silicone and the ratio of the silicone phase to he active phase is in the range of 1:1-1:4. Optional ingredients include the use of non-volatile silicones, volatile silicones and organic emollients.
U.S. Pat. No. 6,033,651 describes a single phase aqueous gel composition comprising 0.05-50% of a polysaccharide gellant, and 1-30% of an antiperspirant active ingredient solubilized in the aqueous single phase wherein the composition is formed with a water and an oil emulsion comprising a gelled aqueous phase comprising a polysaccharide gellant and an antiperspirant active ingredient solubilized in the aqueous single phase; and an oil phase.
Historically, suspension products such as sticks have exhibited better efficacy than emulsion products. Previous attempts have not successfully overcome the problems of improving efficacy and achieving satisfactory formation of emulsions. Thus, it is an object of this invention to provide improved anhydrous emulsions which exhibit improved efficacy which efficacy is comparable to that achieved in suspension products and, at the same time, have a stability profile that allows for satisfactory stability on the shelf. Another issue is the formation of emulsions which are stable on the shelf but which destabilize sufficiently after application to a skin surface so as to release an efficacious amount of an active ingredient. Thus, it is an object of the present invention to provide emulsions with those characteristics. It is also an object of this invention to provide gel or soft solid compositions which can, if desired, be formed into clear compositions. It is still another object of this invention to provide compositions that can, if desired, be formed into clear compositions without the use of microemulsions
SUMMARY OF THE INVENTION
This invention relates to an anhydrous cosmetic composition comprising:
(a) 15-33% of an external phase (also called the oil phase) which is made with at least one selected naphthalate organic ester; a volatile silicone based emulsifier; and a volatile silicone; and
(b) 67-85% of an internal phase which is made with an active ingredient, such as an antiperspirant active, in a solvent (especially a glycol or polyglycol solvent) wherein the conductance of the composition is at least 250, particularly 300, more particularly 400 and especially 500 micro Siemens at a loading of at least 7% by weight level of antiperspirant active as measured by the test described below.
For the external phase all or a major portion of what would have been a non-volatile silicone component has been replaced by the naphthalate ester. While a dimethicone copolyol is still included, the use of this particular naphthalate ester obviates the need for the use of any other non-ionic emulsifiers. Also, while small amounts (for example, 0-5%) of a non-volatile silicone may be included, it is preferred that the compositions be made without the addition of non-volatile silicones.
DETAILED DESCRIPTION OF THE INVENTION
The emulsions of this invention comprise an external and an internal phase as described below:
External Phase comprising
(a) 0.1-25% (particularly 0.5-25% and more particularly 2.5-15%) of an organic naphthalate ester (especially 2,6-di-(ethylhexyl)naphthalate having a refractive index in the range of 1.43-1.60, which is not soluble in alcohol or glycols (except in minor amounts such as up to 1.0%)and which is capable of releasing an antiperspirant active to achieve a specified conductivity,
(b) a sufficient amount of a silicone copolyol to achieve a solids content of 0.25-10% (particularly 1.0-3.0%) wherein the silicone copolyol may be added with or without solvent;
(c) a sufficient amount of a volatile silicone (for example, a cyclomethicone such as a D5 cyclomethicone) to achieve a quantum sufficient (“q.s.”) amount of the external phase as 15-33% (for example, wherein part of the volatile silicone may be added in a silicone copolyol which itself is obtained already mixed with a volatile silicone as a solvent, such as a 40-48% dimethicone copolyol in cyclomethicone);
(d) 0-5% of a sili

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