Elastomeric silicone containing an active ingredient

Details Elastomeric silicone containing an active ingredient Elastomeric silicone containing an active ingredient

1999-05-24

2001-01-02

Dawson, Robert (Department: 1712)

Drug, bio-affecting and body treating compositions

Topical body preparation containing solid synthetic organic...

Skin cosmetic coating

C424S065000, C424S070100, C424S076100, C424S401000, C523S102000, C523S103000, C523S105000, C523S122000, C524S231000, C524S709000, C524S714000, C524S722000, C524S725000, C524S726000, C524S751000, C524S754000, C524S755000, C524S759000, C524S762000, C524S765000, C524S770000, C524S773000, C524S774000, C524S792000, C524S837000, C524S861000, C524S862000, C528S015000, C528S025000

Utility Patent

active

06168782

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
FIELD OF THE INVENTION
This invention is directed to crosslinked three-dimensional gelled networks of elastomeric silicones, especially elastomeric silicone polyethers, containing an active ingredient and an oil. The compositions can be used in personal and health care applications, personal hygiene, and household cleaning applications.
BACKGROUND OF THE INVENTION
While U.S. Pat. No. 5,811,487 (Sep. 22, 1998) and U.S. Pat. No. 5,889,108 (Mar. 30, 1999), each teach processes for making elastomeric silicone polyethers containing oils and solvents, neither patent describes a process in which an elastomeric silicone polyether is made in the presence of an active ingredient as defined herein.
Thus, neither patent teaches the inclusion of an active ingredient such as a vitamin, antimicrobial agent, sunburn prevention agent, astringent, or hormone, for example, during the gelation stage, i.e., the crosslinking step, of the reaction.
This is significant because it now enables one to successfully entrap an active ingredient into the silicone gel matrix of such elastomeric silicone polyethers. Unexpectedly, a structural determination by
29
Si nuclear magnetic resonance (NMR) revealed actual chemical bonding of some active ingredients, i.e., vitamin E, to the silicone gel matrix of the elastomeric silicone polyether. This is both beneficial and an advantage, as it now provides an avenue for entrapping vitamins, and other types of active ingredients, in cosmetics, personal care products, and pharmaceuticals; and for controlling their release in various types of delivery systems.
Thus, it will be demonstrated herein that elastomeric silicone polyethers can be made in the presence of active ingredients such as vitamin E. For example, vitamin E was added during the crosslinking step of the reaction. The reaction produced a clear gel with a golden tint, containing about 15% by weight of the elastomeric silicone polyether. Upon further dilution of the gel, it was found that the final product remained clear and had a golden tint. The vitamin was noted to be stable and entrapped in the gel. Other active ingredients such as antimicrobial agent 5-chloro-2-(2,4-dichlorophenoxy)phenol, i.e., TRICLOSAN; sunburn prevention agent 2-ethylhexyl methoxy cinnamate, i.e., OCTYLMETHOXY CINNAMATE; astringents aluminum chlorohydrate and aluminum zirconium tetrachlorohydrex glycine complex; and estradiol, a female sex hormone; were also successfully entrapped in these gel matrices of elastomeric silicone polyether.
BRIEF SUMMARY OF THE INVENTION
This invention relates to a composition which is an elastomeric silicone, especially an elastomeric silicone polyether containing an active ingredient, prepared by reacting (A) an ≡Si—H containing polysiloxane and (B) a mono-alkenyl polyether in the presence of a platinum catalyst, until (C) an ≡Si—H containing polysiloxane with polyether groups is formed; and reacting (C) the ≡Si—H containing polysiloxane with polyether groups and (D) an &agr;,&ohgr;-unsaturated hydrocarbon such as an &agr;,&ohgr;-diene, &agr;,&ohgr;-diyne, or an &agr;,&ohgr;-ene-yne, in the presence of (E) an active ingredient, (F) an oil, and a platinum catalyst, until a silicone elastomer is formed by crosslinking and addition of ≡SiH across double or triple bonds in the &agr;,&ohgr;-unsaturated hydrocarbon. The reaction is allowed to continue until there is formed a crosslinked three-dimensional gelled network of an elastomeric silicone polyether containing the active ingredient and the oil. The composition can be prepared using an oil-soluble as well as a water-soluble active ingredient.
It should be clearly understood, that within the context of this invention, the phrase active ingredient and the term “oil” are not synonymous. Thus, the active ingredient is not the “oil”, and the “oil” is not the active ingredient.
The invention further relates to emulsions and multiple emulsions containing the composition.
In this regard, it is noted that multiple emulsions are composed of droplets of one liquid dispersed in larger droplets of a second liquid which are then dispersed in a final continuous phase. Generally, the internal droplet phase will be miscible with or identical to the final continuous phase. For example, in a water-in-oil-in-water multiple emulsion W/O/W, the internal and external phases are aqueous.
For a W/O/W system, in which the final continuous phase is aqueous, the primary emulsion is a water-in-oil emulsion W/O, which is then emulsified into the final aqueous phase.
For the purpose of clarity, and according to recognized standards of nomenclature used for W/O/W systems, the aqueous phase of the primary emulsion is designated as W
1
, and the primary emulsion is designated as W
1
/O. The primary emulsion W
1
/O includes an oil phase which is designated as O. After the primary emulsion W
1
/O has been further dispersed in the second aqueous phase designated as W
2
, the complete multiple emulsion system is designated as W
1
/O/W
2
.
These and other features of the invention will become apparent from a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
According to this invention, an elastomeric silicone, especially an elastomeric silicone polyether containing an active ingredient, can be prepared and used as generally depicted in one or more of the several processing steps shown below:
Step 1: Incorporation of the Polyether
≡SiH siloxane+mono-alkenyl polyether+Pt catalyst→≡SiH siloxane with polyether groups
Step 2: Gelation
≡SiH siloxane with polyether groups+active ingredient+oil+≡SiH siloxane (optional)+&agr;,&ohgr;-unsaturated hydrocarbon
gel/elastomer
Step 3: Shearing & Swelling—Optional
gel/elastomer+additional oil+additional active ingredient+quencher→paste
Step 4: Emulsification/Preparation of Primary Emulsion—Optional silicone gel/elastomer/paste+H
2
O+other active ingredients+shear→primary emulsion W
1
/O
Step 5: Preparation of Multiple Emulsion W
1
/O/W
2
—Optional
W
1
/O+H
2
O+shear→W
1
/O/W
2
Multiple Emulsion
In Step 1, the molar ratio of the mono-alkenyl polyether to the ≡SiH in the ≡SiH siloxane should be between 0.9:1 to 1:100.
The weight ratio of the active ingredient to the weight of the ≡SiH siloxane with polyether groups and the &agr;,&ohgr;-unsaturated hydrocarbon can be from 1:98 to 2:1, but preferably is between 1:15 to 1:5. The weight ratio of the “oil” to the weight of the ≡SiH siloxane with polyether groups and the &agr;,&ohgr;-unsaturated hydrocarbon can be from 1:1 to 98:1, but preferably is between 5:1 to 15:1. The ratio of the ≡SiH in the ≡SiH containing siloxane with polyether groups and the &agr;,&ohgr;-unsaturated hydrocarbon can be from 2:1 to 1:2, but preferably is 1:1.
In optional Step 3, the silicone paste may contain 60-98 percent by weight of the active ingredient and/or the oil. In Steps 4 and 5, the weight ratio of water to the silicone paste can be 95:5 to 5:95.
If desired, post cure caused by residual crosslinking hydrosilylation reactions occurring in silicone elastomers can be terminated by introducing an ≡SiH quenching agent such as a vinylsiloxane or a vinylsilane. While vinylsiloxanes and/or vinylsilanes can be used to completely terminate post cure, vinylsiloxanes are preferred to react with ≡SiH over other types of alkenylsiloxanes. In the process of making compositions according to the present invention, a vinylsiloxane can be introduced at the shear & swell Step 3. When this is carried out, any on-going reactions of residual functionalities will be shifted to reactions between the incoming vinylsiloxane and the residual ≡SiH, with the result that crosslinking

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