Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
1998-11-20
2001-08-21
Travers, Russell (Department: 1617)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
C424S405000, C424S450000, C514S358000, C514S938000, C516S201000
Reexamination Certificate
active
06277360
ABSTRACT:
This application claims foreign priority of United Kingdom 9725013.8, filed Nov. 26, 1997.
1. Field of the Invention
The present invention relates to washing compositions, more particularly to washing compositions for washing a surface to deposit thereon a solid active agent, such as particles of a solid antimicrobial substance. Such washing compositions include compositions for washing hair or skin, such as hair shampoos, conditioners, body shampoos, shower gels, facial washing compositions, bar soaps and bath foams. They may also include compositions for household cleaning, such as hard surface cleaners.
2. Background and Prior Art
Difficulties arise in achieving effective deposition of solid active agents onto a surface such as skin or hair when the solid active agent is delivered by means of incorporation into rinse-off compositions, typically hair and body shampoos, conditioners and the like. Frequently, such active agents are preferentially rinsed away from the intended site of deposition, rather than being deposited thereat.
U.S. Pat. No. 5,037,818 describes that the presence of certain cationic polymers in aqueous washing compositions can enhance the deposition of water-insoluble particles such as solid antimicrobials.
There remains the problem, however, that the typical, preferred types of antimicrobial (such as sulphur, selenium disulphide and heavy metal salts of pyridinethione) are relatively dense materials and have a tendency to settle out on storage, from compositions into which they are incorporated. Therefore, in order for compositions containing these types of active agent to be aesthetically acceptable in the package and to provide a consistent, effective level of performance, without requiring vigorous shaking of the package in which they are contained, it is conventional practice to suspend them in the composition with a suspending agent. Examples of commonly used suspending agents include crystalline suspending agents (such as ethylene glycol distearate), inorganic structurants (such as swelling clays) and hydrophilic polymeric thickening agents (such as carbomers). Although these materials are effective for suspending particulate matter, they can adversely affect lathering performance, impart an undesirable cloudy appearance to the composition, and, in particular, mitigate against effective deposition of the active agent on the desired site, thereby reducing performance.
The present invention seeks to solve the above problems and to facilitate and/or enhance deposition of solid active agents, such as particulate antimicrobials, from washing compositions, particularly rinse-off compositions.
EP 0 552 024 describes a rinse-off cleaning composition including an emulsion comprising an internal oil phase of a silicone-type oil, in which the internal phase contains a surfactant soluble cosmetic agent, preferably dissolved therein. Phenylsilicones are particularly preferred silicone-type oils. Other alkyl-silicones are said to be less preferred owing to their inability to dissolve the hydrophobic materials which are the preferred cosmetic agents. The compositions are said to be particularly useful for enhancing deposition of surfactant soluble sunscreen materials from cleansing compositions such as shampoos.
We have now surprisingly found that solid active agents, such as particulate antimicrobials, can be successfully incorporated as a dispersed phase into the silicone phase of a silicone emulsion. Incorporation of the solid active agent into the silicone phase in this way enhances deposition and delivery of the solid active agent from a rinse-off washing composition, particularly in conjunction with a cationic polymer. Careful control of the silicone particle size may also, advantageously, enhance targeting of the active agent to the hair follicle.
SUMMARY OF THE INVENTION
In a first aspect, the present invention provides a washing composition for washing a surface to deposit thereon a solid active agent, the washing composition comprising an emulsion of silicone droplets, the silicone droplets comprising:
(a) a continuous silicone phase, and;
(b) a dispersed phase of solid particulate active agent.
In a second aspect, the invention provides a method of making an emulsion of silicone droplets comprising:
(a) a continuous silicone phase, and;
(b) a dispersed phase of solid particulate active agent,
for incorporation into a washing composition, the method comprising the steps of:
(a) dispersing the solid active agent into silicone fluid, and
(b) emulsifying the dispersion so obtained, thereby forming an emulsion of silicone droplets comprising:
(a) a continuous silicone phase, and;
(b) a dispersed phase of solid particulate active agent.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS
The Emulsion
Washing compositions in accordance with this invention comprise an emulsion of silicone droplets, the silicone droplets comprising a continuous silicone phase, and a dispersed phase of solid particulate active agent.
The emulsion itself has a continuous phase (in which the silicone droplets are emulsified), which comprises one or more surfactants, at least as emulsifying agents for the silicone droplets, which may be present in an amount of from 0.1 to 50%, preferably 0.5 to 30%, typically 1 to 10% by weight of the emulsion.
Suitable emulsifiers are well known in the art and include anionic and nonionic emulsifiers. Examples of anionic emulsifiers are alkylarylsulphonates, e.g., sodium dodecylbenzene sulphonate, alkyl sulphates e.g., sodium, lauryl sulphate, alkyl ether sulphates, e.g., sodium lauryl ether sulphate nEO, where n is from 1 to 20 alkylphenol ether sulphates, e.g., octylphenol ether sulphate nEO where n is from 1 to 20, and sulphosuccinates, e.g., sodium dioctylsulphosuccinate.
Examples of nonionic emulsifiers are alkylphenol ethoxylates, e.g., nonylphenol ethoxylate nEO, where n is from 1 to 50, alcohol ethoxylates, e.g., lauryl alcohol nEO, where n is from 1 to 50, ester ethoxylates, e.g., polyoxyethylene monostearate where the number of oxyethylene units is from 1 to 30.
The continuous phase of the emulsion may, and preferably does, comprise water, preferably in an amount of from 0.1 to 70% by weight, typically 0.5 to 50% by weight of the emulsion.
Silicone Phase
Suitable silicones for the silicone phase are non-volatile silicone fluids, which may be one or more polyalkyl siloxanes, one or more polyalkylaryl siloxanes, or mixtures thereof. The silicone is present in an emulsified form, as dispersed droplets.
Suitable polyalkyl siloxanes include polydimethyl siloxanes which have the CTFA designation dimethicone, having a viscosity of from 5 to 1,000,000 centistokes at 25° C. These siloxanes are available commercially from the General Electric Company as the Viscasil series and from Dow Corning as the DC 200 series. The viscosity can be measured by means of a glass capillary viscometer as set out further in Dow Corning Corporate Test Method CTM004 Jul. 20, 1970.
Also suitable is polydiethyl siloxane.
Also suitable are silicone gums, such as those described in U.S. Pat. No. 4,152,416 (Spitzer), and on General Electric Silicone Rubber product Data Sheet SE 30, SE 33, SE 54 and SE 76. “Silicone gum” denotes polydiorganosiloxanes having a molecular weight of from 200,000 to 1,000,000 and specific examples include polydimethyl siloxane polymers, polydimethyl siloxane/diphenyl/methylvinylsiloxane copolymers, polydimethylsiloxane/methylvinylsiloxane copolymers and mixtures thereof.
Aminofunctional silicones which have the CTFA designation amodimethicone, are also suitable for use in the compositions of the invention, as are polydimethyl siloxanes having hydroxyl end groups (which have the CTFA designation dimethiconol).
The optimum viscosity for the silicone phase will depend on the physical properties of the solid active agent to be dispersed therein. In cases where the solid active agent is an antimicrobial such as a heavy metal (typically zinc) pyridinethione, it is generally advisable that the viscosity of the silicone phase is at least 10,000, preferably a
Carew Peter Simon
Gallagher Peter
Konidaris Peter Christopher
Lam Stanley
Reid Euan Stuart
Boxer Matthew
Helene Curtis Inc.
Travers Russell
Wang Shengjun
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