CA2265465C - Aqueous solution compositions comprising polymer hydrogel compositions - Google Patents

Abstract

The invention relates to hydrogel dispersions/particles capable of trapping water insoluble beneficial agent, yet capable of disintegrating smoothly to impart desirable in use characteristics. A process for preparing the hydrogel dispersions/particles is also described.

Description

?101520253035CA 02265465 l999-02- 19W0 98/08601 PCT/EP97/04751lAQQEOQS SQLQTLQE QQMPQSITIQN§ QOMPRI§I?§P LYMER HYDR EL P ITBACKGROUND OF THE INVENTIONFI LD F‘ THE I EThe present invention relates to novel large hydrogelparticles suspended in an aqueous medium and to a continuousextrusion/mixing process for making these kind of hydrogelparticles. The hydrogel particles comprise two different highmolecular weight polymers. One is insoluble in the aqueousmedium and is used for network formation and gel integrity.The other is soluble in the aqueous medium and helps controlgel swelling and gel strength; Water insoluble materials areentrapped or encapsulated inside the network formed by thesetwo polymers and are thus more efficiently delivered from theaqueous composition (e.g., liquid cleanser containing thehydrogel particles). Gel particles with controllable sizeand controllable gel strength are prepared simply by firstadding (e.g. injecting) an aqueous solution containing thetwo polymers and the water insoluble material into theaqueous medium to form elongated soft polymer gel noodles,which noodles are then cut/broken (e.g., through mixing ormechanical agitation) into desirable gel particle size.BA ND OF THE I ENT NLiquid cleansers or other compositions that can deliverskin benefit agents to provide some kind of skin benefits aredesired and are known in the art. The use of silicone oildroplets to provide enhanced moisturization benefits, forexample, is known.?101520253035WO 98/08601CA 02265465 l999-02- 19PCT/EP97l04751One method used for enhancing delivery of benefitagents (e.g., silicone and vegetable oil) to the skin or hairis through the use of cationic hydrophilic polymers such asPolymer JR” from Amerchol or Jaguar”“ from Rhone Poulenc.This method is disclosed, for example, in EP 93,602; WO94/03152; and WO 94/03151.both the deposition polymer and the generally small sizedIn each of these references,silicone particles are uniformly distributed throughout theentire liquid cleanser composition (i.e. there are noconcentrated "pockets" of benefit agent).In other references, hydrophilic polymers are themselvesincorporated into liquid cleansers or aqueous solutions toprovide various benefits. For example, hydrophilic polymerssuch as guar gum, polyacrylamides, polyacrylic acid andpolymer JR” are disclosed in U.S. Patent Nos. 4,491,539;4,556,510; 4,678,606; 5,002,680 and 4,917,823 as thickeners,lather modifying agents or skin feel agents. Again, in allcases, the polymers are uniformly incorporated or distributedthroughout the entire surfactant composition to provide theclaimed benefits.In no reference is there taught that enhanced depositionof water—insoluble skin benefit agent from cleanser oraqueous medium, or that enhanced in—use cleanser propertiesby hydrophilic polymer, can be achieved using separatehydrogel particles or dispersion acting as a type ofstructure to contain or entrap the benefit agent in aconcentrated form.Unexpectedly, applicants have now found that, if thebenefit agent is incorporated into a liquid composition inthe form of an integral hydrogel carrier containing thebenefit agent (i e., discrete aqueous phase trapping thebenefit agent), then the level of deposition of the benefit?C5350}_1O}_xU]l \)(D253035CA 02265465 l999-02- 19agent on the skin or other substrate is significantlyenhanced compared to either typical liquid or to a liquid gela cationiccomposition containing a polymer agent (typically,deposition agent such as a cationic guar) to help deposit thebenefit agent. The amount of deposition is also higher thanfor compositions having oil droplets dispersed throughout thecomposition in the absence of a deposition aid, particularlywhen small sized particles are used. Other than enhanceddeposition, applicants have also found that the separatehydrogel particles enhance the cleanser's in—use sensorysmooth and creamy feel) when the cleanserproperties (i.e.,or aqueous composition generally is rubbed on the skin.Attempts have been made in the art to deliver somebeneficial material in gel particles, but none has beensuccessful in both retaining the agent in composition while(e g., rubbing).easily delivering it at end useU.S. 5,089,269 to Noda et al., for example,discloses a cosmetic composition containing improved gelatinPatent No.capsules containing hydrophobic component coated by a gelatinfilm swollen with water. Previous gelatin gel or otherhydrogels such as agar, alginate or carrageenan coatedcapsules required a strong breaking force to break the capsuleto release the encapsulated ingredients. In some instancethese capsules were only slid over skin surface when they wererubbed onto the skin. This patent claimed improved gelatincapsules that overcame the above non—desirable properties.However, similar problems occurred, as described in thepatent, when the improved capsule was smaller than lOO um orlarger than lOOO pm. The improved gel coated capsules eitherbecame too rigid to be broken or tended to escape from theThus, neither this orfingers or palm during application.other art teaches hydrogel compositions such as that of theinvention which can retain benefit agent and efficientlyAMENDED SHEET?C6360lO202530CA 02265465 l999-02- 19release them as desired. Further the reference fails to teacha method of forming such hydrogel containing aqueouscompositions.EP 0,355,908 Al claims a process to make polysaccharidegel particles such as agar, carrageenan or gellan gelparticles with size less than lOO pm for food, skin lotionsor cleansers applications. The document also teaches thatwater—insoluble substances suitable for personal careproducts may be included inside the gel particles. Thesekind of gel particles, without further modification, areagain too rigid to easily break and do not provide smoothrub—in properties when the particle size is large,U.S. 4,777,089 and 4,908,233, to Takizawa,disclose microcapsule containing hydrous compositionsPatent Nos.prepared by simple coacervation process. In accordance withthese patents, the capsule was prepared using two differentwater soluble polymers by a simple coacervation process.Upon addition of organic or inorganic salts the firstpolymer phase separated and the second polymer underwent nophase separation. Without the second polymer, the firstpolymer failed to enclose the capsule core material or thecapsule became agglomerated into a coarse mass if thecapsules were formed.In no reference is there taught that hydrogel particlescan be formed using a combination of two different watersoluble polymers, nor is there taught the process for makingthose kind of hydrogel particles..ddEHDED SHEET?101520253035WO 98/08601CA 02265465 1999-02-l9PCT/EP97/04751BRIEF SUMMARY OF THE INVENTIONThe present invention relates to aqueous compositionscontaining novel hydrogel particles formed by two differentwater soluble polymers. The hydrogel particles "trap" waterinsoluble beneficial agents in a network formed by these twopolymers. The polymer network which entraps the benefitagents disintegrates smoothly when rubbed on a substrate suchas skin in order to impart desirable in use characteristics(e.g., smooth, rich, creamier feel) to the composition. Moreparticularly, the aqueous composition comprises:(a) 40 to 95% by wt. of an aqueous solution withviscosity higher than 300 centipoise (cps), preferably higherthan 1,000 cps, more preferably higher than 3,000 cps,wherein said aqueous solutions contains 0% to 60%, preferably2% to 40%, surfactant and wherein said surfactant, ifpresent, is selected from the group consisting of anionic,nonionic, cationic, zwitterionic , amphoteric surfactant andmixtures thereof; and(b) 5 to 60% by wt. of a hydrogel compositioncomprising:(i) 0.1 to 30% by wt. of hydrogel composition,preferably 0.3-15% of at least one polymer which is solublein water, but which is insolubilized, ideally by thermalgelation, when placed in said aqueous solution; and(ii) 0.2 to 30%, preferably 0.5—l0% by wt. ofhydrogel composition of at least a second polymer which issoluble in water and either soluble or dispersible in saidaqueous solution; and?C6360lO3O35CA 02265465 l999-02- 19l.O to 60% by wt.,of a water insoluble beneficial agent which is entrapped in(i)of said benefi; agent have a particle size preferably of(iii) preferably 5 to 40% by wt.a network formed by polymers and (ii); wherein particlesabout 0.2 to 200 micrometers;said hydrogel preferably having a particle size in therange of from about greater than 25 micrometers, preferablylarger than lOO micrometers, more preferably greater that200 micrometers up to about several centimeters.In one embodiment, said gel forming polymer is selectedfrom the group consisting of gel forming polysaccharidesandsuch as carrageenan or agar, gel forming proteins,thermally gelling synthetic polymers.Preferably said gel forming polymer is a syntheticpolymer selected from the group consisting of N~acrylamdesand homo or copolymers of polyacrylate or methacrylatecontaining polymers incorporating an acrylic or methacrylicester of a long chain branched or straight chain alcohol.(i) is insolubilised, whencontacted with the aqueous solution of itemIdeally the polymer of(a), byprecipitation or coacervation, which is generally caused by(i)precipitation ora change in pH. Typically in such cases the polymerwill be polyglucosamine. Alternatively,coacervation is caused by a change in electrolytepolymer (i)the group consisting of polyvinyl alcohol having MW greaterthan l3,000 and a degree of hydrolysis of from 78% to lOO%;concentration. In such cases, is selected fromand hydroxyalkylcellulose.Ideally, the polymer of (i) is insolubilised by cross-linking with a cross—linker present in the aqueous solution(a). (i) the cross-Thus when the polymer is carrogeenan,_.—vAHENPC“ ?ktt,...(_l.‘_- V?101520253035WO 98/08601CA 02265465 l999-02- 19PCT/EP97/047517linker is potassium ion. Similarly, when the polymer (i) isalgimate, the cross—linker is calcium ion. Again, when thepolymer (i) is polyvinyl alcohol, the cross—linker is boraxion.In another embodiment of the invention, the polymer (ii)is selected from the group consisting of:(a) carboxylic acid containing acrylic polymers;(b) nonvionic polymers selected from the groupconsisting of polyvinyl alcohol, polyvinyl pyrrolidone,modified corn starch and hydroxylalkyl cellulose orhydroxyalkylmethyl cellulose; and(C) cationic polymers.In a further embodiment of the invention, the aqueouscomposition containing the novel hydrogel particles isprepared first by adding (e.g., injecting) a polymer solutioncontaining the said two polymers and the water insolublematerial into the said aqueous medium to form elongated (intheory, there is no limit to the size of the noodle since itcan be continuously extruded), soft (i.e., rigid enough tohold benefit agent, but soft enough to be broken downinitially into smaller particles and later to deliver benefitagent to skin) polymer gel noodles which are then cut intothe desirable gel particle size. More specifically, theaqueous composition is prepared as follows:(a) dissolving the first and the second polymer in waterto form a polymer solution and dispersing the water insolublematerial into the prepared polymer solution to form ahydrogel precursor solution;?101520253035W0 98/08601CA 02265465 1999-02-l9PCTIEP97/04751(b) formulating the aqueous composition such that thefirst polymer is not soluble in said aqueous composition dueto chemical or physical interaction and the second polymer iseither soluble or dispersible; and(c) injecting the hydrogel precursor solution (a) intothe aqueous composition (b) to form elongated soft, hydrogelnoodles and breaking the elongated soft noodles to hydrogelparticles using low shear mixing device.The second polymer or polymers (2)(b) forming thehydrogel composition is a property modifying polymer which isrequired (1) to help stabilize benefit agent in the polymerhydrogel system and (2) to help provide the proper gelstrength of the overall hydrogel composition.The invention also relates to the use of an aqueouscomposition as described above in personal cleansing and, inparticular, skin care creams and products.BRIEF DE RIPTI F THE FI REFigure 1 shows the effect of carrageenan (one ofpossible network forming polymers (2)(a) which insolubilize.in the aqueous medium) concentration on gel strength of ahydrogel particle.Figure 2 shows the effect on gel strength when Acrysol(one of possible property modifying polymers (2)(b) which aresoluble both in water and in aqueous medium), an acrylicpolymer, is combined with carrageenan.DETAILED DESCRIPTION OF THE INVENTIONIn one embodiment, the present invention relates to?CA 02265465 l999-02- 19W0 98/08601 PCT/EP97/04751hydrogel compositions which are uniformly dispersed andstably suspended in aqueous compositions designed forpersonal cleansing or skin care applications. The hydrogelcomposition exists in the aqueous solution as a separate5 polymer gel phase (i.e., formed when at least one polymernetwork forming polymer insolubilizes when placed in theaqueous solution; a second property modifying polymer orpolymers which is soluble or dispersible in the aqueous"solution, is also required) present as macroscopic domains10 (i.e, having a particle size greater than 25 micrometers,preferably greater than 100 micrometers, up to about severalcentimeters). Furthermore, these domains are capable oftrapping water insoluble agents, hereafter designated the"benefit agent“, within the gel structure, i.e., inside a web15 or network formed by the network forming polymer(s) and theproperty modifying polymer(s). The hydrogel compositionmust have sufficient gel strength (generally provided by thefirst network forming polymer(s)) to retain the integrity ofthe discrete domains, and to trap and hold the insoluble20 benefit agent(s) during processing and storage of the aqueouscomposition. However, the hydrogel must also be soft enoughand capable of disintegrating smoothly when the compositionis applied to and rubbed onto the intended substrate, such asskin, without causing any undesirable feeling of foreign25 matter or grittiness, due to the breaking or due to thecomponents of the hydrogel particles. The softness of the gelparticles can be manipulated by the amount of propertymodifying polymer(s) and network forming polymer(s)incorporated into the gel composition.30In a second embodiment of the invention, the hydrogeldispersions or structures are generally prepared by firstemulsifying or dispersing the water insoluble benefit agentin an aqueous polymer solution containing both the network35 forming polymer and the property modifying polymer to form an ?C6360lO2O253O35CA 02265465 l999-02- 191Oemulsion or dispersion. This aqueous polymer solution whichcontains the dispersed benefit agent will henceforth bedesignated as the "hydrogel precursor solution". The hydrogelprecursor solution containing the dispersed benefit agent (andalso containing both the first and second polymers defined as(2)(a) and (2)(b)mixed with an appropriate aqueous solution under suchabove) is then added or injected to andconditions that the hydrogel dispersion precursor becomes(2)(a))aqueous solution to form spherical,insoluble (due to component upon contact with thenoodle shaped or in somecases irregular shaped hydrogel domains uniformly dispersed insaid aqueous solution.Hydrogel dispersion can be accomplished either in abatch wise process or in a continuous process depending onhow the hydrogel precursor solution and the aqueouscomposition are mixed. A batch process such as an overheadmixer or a flotation machine or a continuous process such asa two fluid coextrusion nozzle, an in—line injector, an in-line mixer or an in—line screen can be used to make thehydrogel dispersion. The size of the hydrogel composition inthe final composition can be manipulated by changing themixing speed, mixing time, the mixing device and theviscosity of the aqueous solution. In general, by reducingthe mixing speed, decreasing the mixing time, lowering theviscosity of the aqueous solution or using a mixing devicethat produces less shear force during mixing, one can producehydrogel compositions of larger size. The size of thehydrogel domains (e.g , particles), should have at least onedimension (e.g., the diameter) that is larger than 25 um andpreferably larger than 100 um to allow optimal transfer ofthe hydrogel to the substrate during the rubbing process.The diameter may be as high as several centimeters.Injection/low shear mixing processes are preferred for makingthe hydrogel particles. The hydrogel precursor solution is?101520253035W0 98/08601CA 02265465 l999-02- 19PCT/EP97/04751llinjected to or co—extruded simultaneously with the aqueoussolution to form elongated soft hydrogel noodles. In theory,the noodles have no upper size limit as they are extruded.(As noted, after mixing, hydrogel particles should be atleast 25 microns). The prehardened soft hydrogel noodles isthen broken to irregular shape of hydrogel particles usinglow shear mixing devices such as low speed flotation machineor mechanical mixer in a batch process or in—line staticmixer or in~line screen in a continuous process. The in—linemixing process is preferred due to better trapping orretention of water insoluble benefit agents inside the gelparticles and better control on the size of the hydrogelparticles. The prehardened elongated hydrogel noodle shouldbe soft enough such that it can be broken easily at the lowshear mixing condition. If the prehardened hydrogel noodle istoo rigid then the hydrogel noodles tend to plug the in—linemixer or entangle with the mechanical mixer causing problemsduring the process. The rigidity of the prehardened hydrogelnoodle can be manipulated easily by the composition of thehydrogel precursor solution or the composition of the aqueoussolution and the hardening time of hydrogel noodles in theaqueous solution. In general the hydrogel noodle‘s rigiditycan be reduced by reducing the amount of network formingpolymer (2(a)) or increasing the level of property modifyingpolymer (2(b)) in the hydrogel precursor solution; byreducing the hardening time of hydrogel noodle in the aqueoussolution; and by reducing the concentration of cross—linkingagent in the aqueous solution.H r 1 and A ous m osi i nThe hydrogel and aqueous composition comprising suchcomprise three essential components: i) a hydrogel formingpolymer system (comprising a first polymer which?101520253035W0 98/08601CA 02265465 l999-02- 19PCT/EP97/0475112insolubilizes upon Contact with a suitable aqueous solutionfor gel network formation; and a second property modifyingpolymers which stabilizes the benefit agent and/or modifiesgel strength); ii) a water insoluble benefit agent(components (i) and (ii) together form the "hydrogel"composition when formed in the aqueous solution composition(iii)); and, iii) an aqueous solution composition capable ofsuspending the hydrogel and maintaining its integrity due toinsolubility of first polymer. Each of these components isdescribed in greater detail below.As noted, the hydrogel structure or compositioncomprises (i) a hydrogel forming polymer system (containingat least two polymers) and (ii) a water insoluble benefitagent .(i) H ro e1 F rmin P 1 r mPolymer systems useful for forming hydrogels (component(i) above) with desirable properties comprise in turn (a) afirst polymer which is soluble in water but insolubilizeswhen placed in an aqueous solution composition (component(iii) above); and (b) a second property modifying polymerwhich ensures the final hydrogel composition is not so strongthat it will not disintegrate smoothly when the hydrogel isapplied to a substrate, e.g , skin. and but still hassufficient gel strength to retain the benefit agent duringprocessing and storage.Together polymers (a) and (b) form a web or networkwhich retains the benefit agent. Each of polymers (a) and(b) and the mechanism whereby polymer (a) is insolubilized inthe surfactant composition are discussed in greater detailbelow.?C6360l0l52530CA 02265465 l999-02- l9l3(a) First PolymerThe first polymer is, in its broadest sense, defined asany water soluble polymer that is made insoluble when placedin the aqueous solution composition (iii). Thisinsolubilization is accomplished using one of the followinginsolubilization mechanisms:(1) Thermal gelatign Suitable polymers that exhibitthis type of gelling behaviorbya temperature higher than about 40-50°C and which form a gel(i.e., can be made insolublethermal gelation) are those that are soluble in water atafter the polymer solution is cooled to room temperature.Examples of such polymers include: i) gel formingpolysaccharides such as carrageenans or agars.Particularly preferred polymers of this type are thecarrageenan polymers. Particularly suitable carrageenansare those manufactured by the FMC corporation and sold underii) gelthe trade name Gelcarin GP9ll, and Gelcarin 379;forming proteins. Particularly preferred gel formingproteins are gelatins. Suitable gelatins include Gelatin G9382(trademark) and G 2625and iii) thermally gelling synthetic polymershomo or copolymers or(trademark)sold by SigmaChemicals;such as poly (N—isopropylacrylamide)polyacrylate or methacrylate containing polymers thatincorporate as one of the monomer units an acrylic ormethacrylic ester of a long chain and preferably linearExamples of the latter class of polymers are thosesold by Landec Labs Inc. under the trade name Inteliners.alcohol.(2% PreQiQitatiQn_Qr_cQacerzationi Suitablepolymers which exhibit this type of behavior are those thatare soluble in water at room temperature but can be madesubstantially insoluble by changing the physical or chemical?101520253035“K)MM?MCA 02265465 l999-02- 19PCTIEP97/0475114properties of the aqueous solution such as, for example, thepH or electrolyte concentration. One example of aparticularly suitable pH sensitive polymer is Chitosan(polyglucosamine) or its various chemically modifiedvariants. Particularly useful chitosans are those sold byPronova Biopolymers under the trade name Seacure 343, andSeacure 443. These materials have a molecular weight rangingfrom 10,000 to 100,000. Chitosan is an especially usefulnetwork forming polymer for the hydrogel compositions of thepresent invention because it can be dissolved in an aqueoussolution with a pH lower than 4.5 to form a uniform hydrogelprecursor solution. Upon mixing this solution with anaqueous solution such as a liquid cleanser which has atypical pH in the range of 5.0 to 7.0, an insoluble polymeris readily formed.Another class of polymers that form suitable hydrogelnetworks by precipitation/coacervation are electrolytesensitive polymers. These polymer will precipitate to forminsoluble networks by adding the polymer solution into aliquid cleanser containing high levels of salt or ionicsurfactants. Examples of such polymers include: polyvinylalcohol having a molecular weight greater than 13,000 Daltonsand a degree of hydrolysis in the range of 78% to 100%; andhydroxyethylcellulose such as those sold by Aqualon Corp.under the trade name Natrosol.It should be understood that the same polymer may be ineither class (2)(a) (i.e., soluble, but insolubilized uponContact with aqueous surfactant solution); or class (2)(b)(i.e., soluble in both water and aqueous surfactantsolutions) depending on what else is in the aqueous solution.Thus, a polymer sensitive to electrolyte concentration mightbe a class (2)(b) polymer in a composition withoutelectrolyte, but become a class (2)(a) polymer in an aqueous?101520253035 WO 98108601CA 02265465 l999-02- 19PCT/EP97/04751l5surfactant solution containing sufficient electrolyte toinsolubilize the polymer. The same is true if certainpolymers become insoluble in the presence of certain cross—linkers. If the cross-linker is not present in the baseformulation, the polymer may be a (2)(b) polymer, but, ifpresent, the polymer becomes a (2)(a) polymer.(3) QrQss—linking: Suitable water soluble polymersexhibiting this type of behavior are those that can formwater insoluble complexes with a water soluble monomeric orpolymeric cross-linker (e.g., salts or polyacrylates). Theinsoluble polymer network can be formed by reacting thepolymer aqueous solution with the cross-linker before orafter adding the polymer aqueous solution into the aqueoussolution composition. Examples of readily cross—linkablepolymers include: 6—Carrageenans which can be cross~linkedwith potassium ions, alginates which can be cross-linked witha calcium ions or polyvinyl alcohols which can be cross-linked with borax ion.(b) second or Property Modifying PolymersThe polymers described above are essential to form thehydrogel as they provide the backbone network without whichthe hydrogel composition can not exist. However, thesepolymers alone are usually too rigid to provide a smooth rub-in properties and are not sufficiently surface active in thehydrogel precursor solution to effectively stabilizeemulsions of or dispersions of water insoluble benefitagents of the type used in the present invention. A secondmore surface active water soluble polymer was found necessaryin forming such dispersions having the required stability.A second function of the property modifying polymerconcerns its effect on gel strength. As stated above, it is?101520253035WO 98/08601CA 02265465 l999-02- 19PCT/EP97/0475116desirable that the hydrogel composition is sufficientlystrong such that the dispersed hydrogel domains/particlesremain discrete in order to effectively trap the benefitagent within their structure, yet that they be sufficientlysoft (non—rigid) that the hydrogel domains/particles rubsmoothly into the skin during product use. This balance canbe achieved by optimizing the polymer composition of thehydrogel.It has been found that certain water soluble polymerswhen incorporated into the hydrogel precursor solution alongwith the first polymer can effectively modify the gelstrength of the hydrogel composition to achieve this balance.The hydrogel strength and the in—use skin feel properties canthus be manipulated easily by controlling the amounts of thenetwork forming polymer (first polymer) and the secondproperty modifying polymer in the hydrogel precursorsolution.A variety of hydrophilic anionic, cationic, amphoteric,and nonionic water soluble polymers can be utilized for thesepurposes. These second polymers can be soluble in theaqueous solution composition (in contrast to the firstpolymers which are not) and have a molecular weight greaterthan 5,000 Daltons, preferably higher than 10,000 Daltons,and most preferably higher than 50,000 Daltons,Examples of water soluble polymers that have been founduseful as property modifying polymers include: i) carboxylicacid containing acrylic polymers such as alkali solublepolyacrylic latexes sold under the trade name of Acrysol orAculyn by Rohm & Haas and cross—linked polyacrylic acids andcopolymers sold by B. F. Goodrich under the trade nameCarbopol; ii) nonionic polymers such as polyvinyl alcoholfrom Air Products sold under the trade name Airvol, polyvinyl?1O1520253035WO 98/08601CA 02265465 l999-02- 19PCT/EP97l0475117pyrrolidone from ISP Technologies Inc., modified corn starchsuch as those sold under the trade name of Capsule or PurityGum Bee by National Starch & Chemicals, hydroxyethylcellulosesold by Aqualon under the trade name of Natrosol;hydroxylpropyl methylcellulose from Dow Chemical namedMethocel and iii) cationic polymers such as modifiedpolysaccharides including cationic guars available from RhonePoulenc under the trade names Jaguar C138, and Jaguar C148,cationic modified cellulose such as Ucare Polymer JR 30 or JR40 from Amerchol, synthetic cationic polymers such aspolydimethyldialkyammonium chloride homo— or copolymers soldunder the trade name Merquat 100, Merquat 550 sold by Calgon,and vinyl pyrrolidone/dimethylamino ethyl methacrylatecopolymer sold under the trade name of Gafquat 755 from GAPChemical.The second component of the "hydrogel" composition isthe benefit agent (component (ii) above). This is describedin greater detail below.(ii) Benefit AgentBenefit agents in the context of the instant inventionare materials that have the potential to provide a positiveand often longer term effect to the substrate being cleaned,e.g., to the skin, hair or teeth. In the case of skin,benefit agents suitable for this invention are waterinsoluble materials that can protect, moisturize or conditionthe skin after being deposited from the aqueous compositionsuch as a liquid cleansing composition.Preferred benefit agents include:a) silicone oils, gums and modifications thereof suchas linear and cyclic polydimethylsiloxanes; amino, alkyl?101520253035CA 02265465 l999-02- 19W0 93/08601 PCT/EP97/047511 8 _alkylaryl and aryl silicone oils;b) fats and oils including natural fats and oils suchas jojoba, soybean, sunflower, rice bran, avocado, almond,olive, sesame, persic, castor, coconut, mink oils; cacao fat,beef tallow, lard; hardened oils obtained by hydrogenatingthe aforementioned oils; and synthetic mono, di andtriglycerides such as myristic acid glyceride and 2-ethylhexanoic acid glyceride;c) waxes such as carnauba, spermaceti, beeswax,lanolin and derivatives thereof;d) hydrophobic plant extracts;e) hydrocarbons such as liquid paraffins, petrolatum,microcrystalline wax, ceresin, squalene, squalane, pristanand mineral oil;f) higher fatty acids such as lauric, myristic,palmitic, stearic, behenic, oleic, linoleic linolenic,lanolic, isostearic and poly unsaturated fatty acids (PUFA)acids;g) higher alcohols such as lauryl, cetyl, styrol,oleyl, behenyl, cholesterol and 2—hexadecanol“ alcohol;h) esters such as cetyl octanoate, myristyl lactate,cetyl lactate, isopropyl myristate, myristyl myristate,isopropyl palmitate, isopropyl adipate, butyl stearate, decyloleate, cholesterol isostearate, glycerol monostearate,glycerol distearate, glycerol tristearate, alkyl lactate,alkyl citrate and alkyl tartrate; sucrose ester sorbitolester and the like;i) essential oils such as fish oils, mentha, jasmine,camphor, white cedar, bitter orange peel, ryu, turpentine,cinnamon, bergamot, citrus unshiu, calamus, pine, lavender,bay, clove, hiba, eucalyptus, lemon, starflower, thyme,peppermint, rose, sage, menthol, cineole, eugenol, citral,Citronelle, borneol, linalool, geraniol, evening primrose,camphor, thymol, spirantol, pinene, limonene and terpenoidoils;?1O1520253035W0 98/08601CA 02265465 l999-02- 19PCT/EP97/0475119j) lipids and lipid like substance such ascholesterol, cholesterol ester ceramides, sucrose esters andpseudoceramides as described in European Patent SpecificationNo. 556 957;k) vitamins such as vitamin A and E, and vitamin alkylesters, including vitamin C alkyl esters;l) sunscreens such as octyl methoxyl cinnamate (ParsolMCX) and butyl methoxy benzoylmethane (Parsol 1789);m) Phospholipids such as lecithins;n) antimicrobial such as 2—hydroxy—4,2',4'—trichlorodiphenylether (DP300) and 3,4,4‘-trichlorocarbanilide (TCC): andmixtures of any of the foregoing components.Another benefit agent contemplated are water solublematerials (e.g., glycerin, enzyme, —hydroxy acid) entrappedin any of the oils mentioned above.The benefit agent is incorporated into the aqueoushydrogel precursor solution (the solution that contains thefirst polymer and the second property modifying polymers).This can be accomplished simply by mixing the benefit agentwith the aqueous hydrogel precursor solution or by pre-emulsifying the benefit agent in an aqueous solution which isthen mixed with the hydrogel precursor solution. In thedirect mixing process low level of surfactants can be addedinto the hydrogel precursor solution to enhanceemulsification and stability of the skin benefit agent. Thebenefit agent is present in the aqueous polymer solution inthe amount of 5 to 65 by wt %, preferably 10 to 40 by wt.% ofthe hydrogel composition. Depending on the mixingconditions, polymer composition (i.e., composition ofpolymers forming hydrogel) and concentration, the size of thebenefit agent particle can vary from 0.2 micrometer up toseveral hundred micrometers. For better stability and?101520253035W0 98/08601CA 02265465 l999-02- 19PCT/EP97/0475120efficient deposition, the particle size of benefit agent ispreferably in the range of 5 to 150 micrometers.As indicated above, the invention comprises an aqueoussolution composition comprising the hydrogel composition morefully defined above. The liquid composition itself isdescribed in greater detail below.(iii) A ueous Solution Com itignAs noted, the invention relates to the aqueous solutioncomposition in which the hydrogel incorporating the benefitagent (i.e., containing the agent in a web produced bypolymers (2)(a) and (2)(b)) is dispersed. Depending on theapplication, the aqueous solution composition can comprisesfrom about 0% to about 60 wt%, preferably 2% to 40 wt% ofsurfactants selected from any known surfactants suitable forpersonal care or cleansing applications. In general, forpersonal cleansing application higher level of surfactantstypically in the range of 5 to 50 wt% are used. Thesurfactants are selected from the group consisting ofanionic, nonionic, cationic, amphoteric and zwitterionicsurfactants and mixtures thereof. It should be noted thatsurfactants are not a necessary component of the compositionand, for example, non—surfactant skin lotion compositions arecontemplated.The aqueous solution composition should be formulated insuch a way that the first water soluble polymer becomesinsoluble upon contact with the aqueous solution composition.It is also critical that the aqueous solution composition iscapable of suspending the dispersed hydrogel phase forhydrogel processing and stable hydrogel suspension. Thisrequires that the liquid compositions have a sufficientlyhigh low—shear viscosity to prevent settling (or creaming) of?10}_..lU]20253035toO\CA 02265465 l999-02- 1921the hydrogel compositions under the action of gravity duringprocessing and storage. This can be achieved by utilizingaqueous solution compositions formulated to have a viscosityand preferably 1,000 cps,at 25°C .of at least 300 cps, morepreferably 3,000 at a shear rate of 10 sec 1 Thisviscosity is generally sufficient to stably suspend the largehydrogel dispersions of the instant invention withoutappreciable gravitational phase separation. As the particlesize of hydrogel dispersion increases, liquids that have ahigher viscosity are required to achieve adequate stability.Viscosity of an aqueous solution composition can beincreased either by the inclusion of polymeric, organic orinorganic thickeners in the composition or by the careful 'selection and combination of surfactants. Both methods areFor example, U.S. Patents 4,917,823,4,678,606 and 5,002,680 teach the use ofwell known in the art.4,491,539, 4,556,510,polymeric thickeners to increase the viscosity of a liquidcleanser, while U.S. Patents 5,236,619, 5,132,037, 5,284,603,5,296,158 and 5,158,699 disclose ways to formulate a stableviscous liquid composition using an appropriate combination ofsurfactants.The surface active agent, when used, can be selected fromany known surfactant suitable for topical application to thehuman body.One preferred anionic detergent is fatty acyl isethionateof formula“ RCO2CH2CH2SO3Mwhere R is an alkyl or alkenyl group of 7 to 21 carbonatoms and M is a solubilizing cation such as sodium,potassium, ammonium or substituted ammonium. Preferably atleast three quarters of the RC0 groups have 12 to 18 carbonpalm or coconut/palm{X‘ \.;;.,',atoms and may be derived from coconut,-I 'a'-.?101520253035CA 02265465 2005-01-0522blends.Another preferred anionic detergent is alkyl ethersulphate of formula:R0 (CI-i:CH;,O) ,,SO_.Mwhere R is an alkyl group of 8 to 22 carbon atoms, nranges from 0.5 to 10 especially 1.5 to 8, and M is asolubilizing cation as before.It should be understood that the anionic surfactant isalso intended to encompass fatty acid soaps.Fatty acid soaps are typically alkali metal or alkanolammonium salts of aliphatic alkane or alkene monocarboxylicacids. Sodium, potassium, mono-, di and tri-ethanol ammoniumcations, or combinations thereof, are suitable for purposesof the invention. The soaps are well known alkali metalsalts of natural or synthetic aliphatic (alkanoic oralkenoic) acids having about 8 to 22 carbons, preferably 12to about 18 carbons. They may be described as alkali metalcarboxylates of acrylic hydrocarbons having about 12 to 22carbons.Examples of soap which may be used may be found in U.S.Patent No. 4,695,395 to Caswell et al. and U.s. Patent No.4.260.507 (Barrett).other possible anionic detergents include alkyl glycerylether sulphate, sulphosuccinates, taurates, sarcosinates,sulphoacetates, alkyl phosphate. alkyl phosphate esters andacyl lactates, alkyl glutamates and mixtures thereof.Sulphosuccinates may be monoalkyl sulphosuccinateshaving the formula:?l01520253035CA 02265465 2005-01-0523RSOZCCHECH ( so,M) co,M;and amido-MEA sulphosuccinates of the formula:RSCONHCHZCI-I2O2CCH2CH < so,M) co2M,-wherein Rsranges from Cfcm alkyl, preferably Cn—Cu alkyland M is a solubilizing cation.Sarcosinates are generally indicated by the formula:RECON (CH3) cH,co2M,wherein Rsranges from Cgcn alkyl, preferably Cu—Cm alkyl.Taurates are generally identified by the formula:RSCONRSCHZCHZSOJM,wherein Rsranges from Cgcm alkyl, preferably Cu—Cu alkyl, R‘ranges from C54; alkyl, and M is a solubilizing cation.Another useful surfactant is alkylethoxy carboxylateindicated by the following formula:R’ (ocH,cH2) ncooM, 'wherein Rsranges from Cgcm alkyl, preferably Cu-C“ andM is a solubilized cation.Harsh surfactants such as primary alkane sulphonate oralkyl benzene sulphonate will generally be avoided.Suitable nonionic surface active agents include alkylpolysaccharides, aldobionamides (e.g., lactobionamides such astaught in U.S. Serial No. 981,737 to Au et al.),ethyleneglycol esters, glycerol monoethers, polyhydroxyamides(glucamide) including fatty acid amides such as taught in U.S.Patent No. 5,312,934 to Letton, primary and secondary alcoholethoxylates, especially the Cagoaliphatic alcohols ethoxylatedwith an average of from 1 to 20 moles of ethylene oxide permole of alcohol.?101520253035CA 02265465 l999-02- 19WO 98/08601 PCT/EP97/0475124The surface active agent is preferably present at alevel of from 1 to 35 wt.%, preferably 3 to 30 wt.%.It is also preferable that the composition includes from0.5 to 15 wt.% of a cosurfactant with skin mildness benefits.Suitable materials are zwitterionic detergents which have analkyl or alkenyl group of 7 to 18 carbon atoms and complywith an overall structural formula.o R2H IR1 —[— C—NI-I (CH2)m—],,-N‘—X—YIR3where R’ is alkyl or alkenyl of 7 to 18 carbon atoms,R2 and R3 are each independently alkyl, hydroxyalkyl orcarboxyalkyl of 1 to 3 carbon atoms,m is 2 to 4,n is O or 1,X is alkylene of 1 to 3 carbon atoms optionallysubstituted with hydroxyl, andY is —CO2— or —SO3—.Zwitterionic detergents within the above general formulainclude simple betaines of formula:R2R’ — N‘ — CHZCO2’R3and amido betaines of formula:?101520253035CA 02265465 l999-02- 19WO 98/08601PCT/EP97/0475125 ‘R:R‘ —[—CONH (CH2),,, —N‘-CH2CO2'1R]where m is 2 or 3.In both formulae R3, R2 and R3 are as defined previously.R‘ may, in particular, be a mixture of Cu and CM alkyl groupsderived from coconut so that at least half, preferably at leastthree quarters of the groups R‘ have 10 to 14 carbon atoms. R2and R3 are preferably methyl.A further possibility is a sulphobetaine of formula:R2IR‘ — N‘— (CH2)3SO3'R3orR2IR‘ —{—coNH (CH2)mN‘—(CH;.);.SO3'IR3where m is 2 or 3, or variants of these in which —(CHg3SO; is replaced byOH—CH;,CHCI-12803"?CA 02265465 l999-02- 19C6360l0l52025303526R5 E5 and Rjin these formulae are as defined previously.Compositions of the invention may be formulated as productsfor washing the skin or hair, e g., bath or shower gels, handwashing compositions, facial washing liquids, shampoos; preand post shaving products; rinse off, wipe off and leave onskin care products.The compositions of the invention will generally be pourableliquids or semi liquids e.g., pastes and will preferably havea viscosity in the range l500 to lO0,000 mPas measured at ashear rate of 10s” at 2TC in a Haake Rotoviscometer RV20.Other typical components of the compositions includeopacifiers, preferably 0.2 to 2.0 wt.%; preservatives,preferably 0.2 to 2.0 wt.% and perfumes, preferably 0.5 to 2.0wt.%.In a second embodiment of the invention, the inventionrelates to a process for preparing an aqueous compositioncomprising hydrogel particles wherein said hydrogel particleshave the following composition:(i) 0.1 to 30% by wt. hydrogel composition of at least onepolymer soluble in water which polymer is insolubilized whenplaced in an aqueous solution;(ii) 0.2 to 30% by wt. hydrogel composition of a polymersoluble in water, and soluble or dispersible in aqueoussolution; and(iii) 1.0% to 60% water insoluble benefit agent entrapped ina network formed by (i) and (ii);wherein the particles of benefit agent(iii) have a particlesize of 0.2 to 200 micrometers;wherein said hydrogel is greater than 25 micrometers;and wherein the size of the hydrogel is greater than that ofthe benefit agent;wt-‘”";'.‘ SFEET?C6360l0l52O253035CA 02265465 l999-02- 1927wherein said process comprises the steps of:(a) dissolving polymer (i) and (ii) to form a polymersolution in water(b) dispersing component (iii) into the polymer solution toform a hydrogel precursor solution;(c) formulating an aqueous solution such that the firstpolymer (i)or dispersible in the aqueous solution;(d)solution to form elongated,is not soluble and second polymer (ii) is solublecombining said hydrogel precursor solution and the aqueoussoft hydrogel noodles when hydrogelprecursor contacts the aqueous solution, the noodles beingsufficiently rigid to entrap benefit agent yet sufficiently softto readily rupture when applied to a substrate; and. 3- /breaking the noodles to hydrogel particles usingmechanical mixer or in—line mixer.In order to better understand the invention the followingnon—limiting examples are provided. As noted, the examplesare not intended to limit the claims in any way.All percentages mentioned are intended to be percentages byweight unless indicated otherwise.EXAMPLESExample 1. Preparation of hydrogel dispersions (i.e.,hydrogel composition) containing silicone oil by a directmixing process.There are a number of ways that a polymeric hydrogel can bedispersed into an aqueous based surfactant composition in suchAll of thetechniques we have found useful take advantage of rapida way that the hydrogel forms discrete domains.gelation or cross—linking that occur for certain types ofwater soluble polymers when their solution environmentchanges, e.g , a change in pH, ionic strength, temperature,type of ion, presence of cross—linker, etc..\(V. ;'.. .—..~—.‘ -. u-1-—- _ -‘?CA 02265465 l999-02- 19C6360l0l525303528This example illustrates how hydrogel dispersion useful inthe present invention can be prepared by directly mixing anappropriate hydrogel forming polymer solution (called thehydrogel precursor solution) with a liquid cleanser usingconventional mechanical stirrer. In this case, the polymersystem is chosen such that the change in pH that arises whenthe hydrogel precursor solution is mixed with the cleansingcomposition induces a phase changes (gelation). Gelation issufficiently rapid that the added precursor hydrogel solution(containing (1) first polymer which insolubilizes when addedto aqueous surfactant solution; (2) second property modifyingpolymer and (3) benefit agent), which itself is watercontinuous, does not first dissolve in the cleansingcomposition but rather forms a discrete dispersed aqueousphase.Preparation of hydrogel precursor solutionA 40% emulsion of silicone oil (60,000 centistokes, ex DowCorning) was formed by mixing 40 parts of the silicone oil to60 parts of aqueous polymer solution which contained 1 wt% ofChitosan (first polymer) (Sea Cure 340(trademark) ex. Protan),0.8 wt% of acetic acid and 3 wt% of hydroxyl ethylcellulose(second polymer) (Natrosol 250 MR (trademark)ex. Aqualon) at400 rpm for 30 minutes using an overhead stirrer. Theemulsion so prepared contained droplets of silicone oil havinga broad size distribution ranging from about 4 pm to 50 umdispersed in the polymer solution.Preparation of hydrogel dispersion by direct mixing12.5 parts of the hydrogel precursor solution containingemulsified silicone oil described above was added to 87.5 partsof a liquid cleanser whose composition is described in Table l.Mixing was accomplished with an overhead stirrer (Model RWZODZMex Tekmar). Two dispersions were prepared that had identicalArntm-p ?CA 02265465 l999-02- 19C6360lO|,_:U 12029chemical composition but differed in the stirring speed used toform the dispersions. In Example lA, the dispersion was mixedat 80 RPM for 25 minutes while for Example 1B the mixing speedwas 200 RPM. Both examples contained irregular shaped hydrogeldomains that themselves contained emulsified silicone oildroplets entrapped within the gel matrix.The compositions of Examples lA and 1B are detailed in Table2 along with some of their physical properties.Table l. Liguid Cleanser QompositionIngredient Wt%Cocamidopropyl Betaine 5.6%Sodium Cocoyl Isethionate 3.5%Sodium Laureth Sulfate 1.4%Glydant XL (trademark) O.l4%Ammonium Sulfate 0.09%Jaguar Cl3S (trademark) 0.9%Perfume 0.42%Deionized Water 87.95% ?101520253035CA 02265465 l999-02- 19WO 98/08601 PCT/EP97/0475130 1Table 2. Composition and properties of hvdrogel dispersionsfgrmed by di egg mixingExample 1A Example 1B Example 2Ingredient Wt% Wt% wt%Silicone Oil 40% 40% 40%Chitosan 0.6% 0.6% 0.6%Hydroxyethylcellulose 1.8% 1.8% —Jaguar C138 — - 1.8%water to 100 to 100 to 100Silicone Oil drop 4—50:m 4-50 m l—25:msizeHydrogel domain size 255 nm 227 nm 157 nmExample 2. Further illustration of hydrogel dispersioncontaining silicone oil prepared by direct mixingA hydrogel precursor solution similar to the one describedin Example 1 but having a different polymer composition wasprepared as follows. 40 parts of 60,000 centipoise siliconeoil was emulsified in 60 parts of aqueous polymer gel solutionwhich contained 1 wt% of Chitosan (first polymer) (Sea Cure 340ex. Protan), 0.8 wt% of acetic acid and 3 wt% of a cationicguar polymer (second polymer) (Jaguar C138 ex. Rhone-Poulenc)at 400 rpm for 30 minutes using an overhead stirrer.12.5 parts of this hydrogel precursor solution containingemulsified silicone was then added to 87.5 parts of the liquidcleanser described in Table 1 and mixed at 80 rpm for 25minutes. This process lead to a dispersion that containedirregular shaped particles of hydrogel in which silicone oildroplets were entrapped in the gel matrix. The compositionand properties of this dispersion are also summarized inTable 2.?CA 02265465 l999-02- 19C6360l0l525303531Example 3. Hydrogel dispersions containing silicone oilprepared by extrusionThis example demonstrates that hydrogel dispersions usefulfor the purposes of the present invention can also beprepared by a coextrusion process. Specifically the exampleillustrates compositions that are prepared by co-extruding ahydrogel precursor solution (containing in this case dispersedsilicone oil) with an aqueous liquid cleaner composition bymeans of a two fluid nozzle. This process produces hydrogelcompositions dispersed in the form of noodle shape particlessuspended in the liquid cleanser composition. The noodleshape hydrogel dispersion gives a unique appearance to theliquid cleanser. Alternatively, the dispersion can beprocessed further by any number of shear techniques to chop orsubdivide the noodles into a desired size range. The processis illustrated for a silicone oil containing hydrogelcomposition, but can be used in conjunction with a greatvariety of materials as will be shown in subsequent examples.Preparation of hydrogel precursor solution dispersed silicone oilSilicone oil was mixed with an aqueous solution of aneutralized carboxyl acid containing acrylic copolymer (secondpolymer) Rohm & Haas)solution with a pH in the range of 7 to 7.5 by mechanical(Aculyn—33(trademark), in an aqueousstirring. In this case the Aculyn-33 was used as the propertymodifying polymer. The oil droplet size, which varied from 5 tolSO pm in diameter, was controlled by the concentration ofAculyn—33 and the stirring speed. Higher concentration andfaster stirring led to smaller oil droplets. An aqueous 6-carrageenan (Gelcarin GP—9ll(trademark), FMC) solution, thefirst polymer (network forming polymer), was added into themixture with gentle stirring (< lOO rpm) at 45—5O °C. For thisexample two3 ‘ y..I ».“.I~'-1 1'.» .:— -~?C63l0l5l\)U1CA 02265465 l999-02- 1932hydrogel precursor dispersions were prepared that differed inthe size of the silicone oil droplets. In one dispersion, thesilicone oil droplet size was in the range of 2-30 um while inthe second dispersion the droplet size fell within 40 -lOO um.Preparation of hydrogel dispersion by coextrusionThe warm (45—50°C) precursor solution described above wasfed into the central orifice of a commercially availablenozzle (Series No. l/4 XA SR45O A ex Bete Fog Nozzle Inc.) bymeans of a high pressure syringe pump (Syringe pump model 40(roomex Harvard Apparatus). Simultaneously, a cooltemperature ~ 22 °C) shower gel formulation (composition shownin Table 3) was injected to the outer orifice of the nozzle toform the final product which contained "noodle-shaped"hydrogel Composition particles. A high pressure syringe pumpwas also used to transfer the cleansing composition, in thiscase a shower gel. The hydrogel and silicone contents in thefinal dispersion were controlled by controlling the ratio ofthe flow rates of the hydrogel precursor and the surfactantcompositions. This ratio was adjusted to ensure that thefinal product contained 5 wt.% silicone oil.The characteristics of the two hydrogel dispersions, Example3A and Example 3B are summarized in Table 4. They consistedof noodle shaped particles of approximately lOOO pm indiameter suspended in the shower gel composition of Table 3~?CA 02265465 l999-02- 19C6360l0l533Table 3. Surfactant cleansing composition used to preparehydrogel dispersions of Example 3Ingredient wt.% .Sodium Lauryl Ether(3) Sulfate 4Cocoamido Propyl Betaine lDodecyl polyglycoside 5Perfume (SG l46, Quest) 1Sorbic Acid 0.37Sodium Citrate. 2H2O 0.49Sodium Hydroxide (l) lCarbopol ETD202O (2) 0.9Antil l4l3 (trademark) (3) 0.97H20 to 100Footnote l: Adjust pH to 5.24 : O.l with NaOHFootnote 2: Cross—linked polyacrylic acidFootnote 3: Polyethylene glycol propylene glycol oleateTable 4. Characteristics offormed by coextrusion (Example 3)"Noodle Shaped"Hvdroqel ParticlesExample Hydrogel Oil Phase DiameterSilicone Oil Noodle's(60,000 cs) Cross-section(um)Polymer Water wt.% DropletSize( Mm)Type wt.% wt.%3A Carrageenan l.2/0.4 38.4 60.0 40-100 l/Aculyn3B Carrageenan l.2/0.4 38.4 60.0 2-30 l/Aculyn- “nilr_«.~,p.:0 5“?CA 02265465 l999-02- 19C6360l015253034Aculyn is neutralized carboxyl acid containing acryliccopolymer,Example 4. Effect of Polymer Composition on hydrogelproperties.This method illustrates how the rheological properties ofthe hydrogel which affect their in—use properties can bemanipulated by the selection and concentrations of network-forming (first) and property modifying (second) polymers.A series of model hydrogel particles were prepared by across—linking method using carrageenan as the network polymerand potassium ions as the cross—linking agent. Thedispersions were made by a variant of the extrusion processdescribed in Example 3 using an aqueous solution of KCl as themodel cleansing composition. The hydrogel dispersionsdiffered only in the concentration of carrageenan (firstpolymer) used in the hydrogel precursor solution which rangedfrom l to 6 wt%. Approximately spherical particles wereformed all having a diameter of about 3000 um.An Instron (Model ll22) was found to be a suitableinstrument to differentiate the strength of various gelcompositions described above. The measurement procedure was asfollows. A hydrogel particle was carefully removed from thedispersion with a spatula and excess liquid was removed byplacing them on a kimwipe. The approximate diameter of thehydrogels was measured with calipers. The hydrogel was thentransferred to a metal platform base of the Instron and a 10Newton load was lowered until it came in contact with thehydrogel particle. The Instron was then turned on and theforce was measured as a function of distance using a chartrecorder. The chart recorder was set at a crosshead speed of l.g?§§?101520253035CA 02265465 l999-02- 19W0 93’ "3501 PCTIEP97/0475lmm/min and a chart speed of 50 mm/min which allowed for a 2Newton full scale load reading. The force was recorded at 0.50mm, l.OO mm, and 1.50 mm. The elastic modules of the sample wascalculated by dividing the force by the section area of thehydrogel and the strain. It should be noted that the particlesremained hydrated during the course of the measurement.The gel strength measure by the above procedure for theseries of model hydrogel particles are shown in Figure 1.These results indicated that the gel strength increasedsignificantly with increasing carrageenan concentration. whenthe polymer concentration was higher than 2 wt%, the gel feltquite hard to the touch, and did not rub smoothly into theskin. Although such particles might trap benefit agents andremain stable during storage, they would not be optimum forcleansing applications because the delivery of the benefitagent would not be uniform, and the composition would feelgritty. These results also indicate that if it was desired todecrease the gel strength of the hydrogel particles this couldonly be achieved by decreasing the concentration of polymerwithin the gel. This would greatly limits the flexibility ofthe technology. As will be shown below, this limitation can beovercome by using a second polymer to modify the properties ofthe hydrogel, e.g., its gel strength.Another set of model hydrogel particles were prepared bythe same procedures used above. Each hydrogel precursorsolution contained 2 wt% carrageenan and from O to 2 wt% of anacrylic copolymer, Acrysol ASE—6O (Rohm & Haas). This is thesecond property modifying polymer. The shape and size of thehydrated particles were all very similar and also similar tothe all carrageenan hydrogels described previously. Theinfluence of added Acrysol ASE—60 on the gel strength ofhydrogel particles formed by cross—linking with K‘is shown inFigure 2. The results indicate that the gel strength?CA 02265465 l999-02- 19C6360lO,4UT20253036decreased significantly with increasing Acrysol concentrationeven though the total concentration of polymer increased.Hydrogels containing carrageenan and Acrysol in a weightratio ranging from 3:1 to 2:1capable of effectively trapping benefit agents such as(arrows in Figure 2) wereemulsified emollient oil e.g., silicone oil, and yet rubbedsmoothly into the skin without noticeable grit.The above example is set forth for illustrative purposes toshow how the gel strength can be tuned by selection of apolymer system comprising an network—forming and propertymodifying polymer. Care must be taken not to attach too muchsignificance to the exact values of gel strength quoted above.We have found that the quantitative effect of the polymercomposition in the hydrogel precursor solution on thestrength of a hydrogel particle depends significantly on thebenefit agentAlthough thetrends are the same, Althoughone skilled in the art can utilize a combination ofnature, particle size, and concentration of athat may be dispersed in the precursor solution.the exact values may change.complex,polymers broadly falling in the definition of network—formingand property modifying agents to achieve the proper balance ofgel strength for each situation.Example 5. Deposition of silicone oil on skin ex-vivo.The potential of various cleansing compositions to depositsilicone oil onto the skin during the washing process wasdetermined using an ex-vivo model based on pig skin. Theprocedure is described below.A 0.5 ml aliquot of the test composition was applied to 5.08cmby 5.08cm (2" by 2”) square strips of excised pig skin that hadfirst been prewetted with tap water at 37 °C.was lathered for 10 seconds and then rinsed for lO seconds underThe composition1 .,._.I\~.r.:ED .-\\'H -AV?101520253035CA 02265465 l999-02- 19wo 98/08601 PCT/EP97/0475137warm running tap water. The skin was then wiped once with apaper towel to remove excess water and allowed to dry for twominutes. A strip of adhesive tape was then pressed onto theskin for 30 seconds under a load of 10 g/cm”. The adhesivetape employed was J—Lar Superclear (TM) tape having a width of3 cm. In this test procedure, the silicone, which haddeposited on the skin, will subsequently be transferred to thetape along with some of the outer skin layers.The amounts of silicone and skin adhering to the tape weredetermined by means of X—ray fluorescence spectroscopy. Thetape strips were placed in an X—ray fluorescence spectrometerwith the adhesive side facing the beam of this machine. A maskis applied over the tape to define a standardized area in themiddle of the tape which was exposed to the X—ray beam. Thesample chamber of the machine was placed under vacuum beforemaking measurements and the spectrometer was then used tomeasure the quantities of silicone and sulphur. The sulphurwas representative of the amount of skin which had transferredto the tape.The amount of silicone and sulphur observed with a cleanpiece of adhesive tape were subtracted from the experimentalmeasurements. The experimental measurements for successivepieces-of tape were added together and the cumulative totals ofsilicone and sulphur were expressed as a ratio of silicone tosulphur per unit area of skin. A higher Si/S ratio correspondsto a higher deposition level. A total of 10 tape strips wereemployed for each measurements.The amount of silicone deposited on excised pig skindetermined as described above for the compositions described inExamples 2-3 are listed in Table 5. It is clear from theseresults that the hydrogel compositions provided significantdeposition of silicone oil to the skin in these tests.?CA 02265465 l999-02- 19C636038Table 5. Deposition of Silicone from Shower GelExample No. Silicone Deposition(Silicon/Sulphur Ratio)Example 2 1.38Example 3A 28.0Example 3B 7.1Control 1 (Note 1) 0.35 Note 1. The control in this example is the shower gel10152O25composition shown in Table 3 which did not contain anysilicone.Example 6. Hydrogel dispersions made with different polymers.This example illustrates that hydrogel dispersions can beprepared with a variety of polymers provided they possess therequired hydrogel forming capabilities and gel strengths. Inthe composition described below, a cationic polymer Chitosan(first polymer) (Seacure 343 ex. Pronova Biopolymer) was usedas the network forming polymer and a cationic modified guar(Jaguar C—13S, Calgon) and a synthetic cationic polymerpolydimethyldialkylammonium chloride (Merquat 100,(trademark)Calgon) were used as the second or property modifyingpolymers. The hydrogel precursor solution was prepared bymixing 35 parts of 60,000 cps silicone oil with 65 parts ofpolymer solution containing 1.5 wt% Jaguar C138, 0.75 wt%Chitosan, 0.10 wt% Merquat 100, 0.35% acetic acid and 0.05 wt%cocoamido propylbetaine at 300 rpm for 15 minutes using anoverhead’stirrer. The resulting emulsion contained siliconeoil droplets with size ranging from 2 pm to 60 um dispersed inthe polymer solution.’r‘\*>iH. . ‘ ‘ ‘ ";‘..."._-nvvu‘ "'?l015CA 02265465 l999-02- 1939The extrusion process described in Example 3 was used toprepare l4.3 wt% dispersions (5 wt% silicone oil based on thetotal composition) of the hydrogels The surfactant systemwas the same as the one used in Example 3 (Table 3) except0.3 instead of 0.97 % of Antil l4l was used in the formula.The hydrogel dispersion comprised noodle shaped particlesdispersions that contained dispersed silicone oil having anaverage droplet size in the range of 2-60 pm.The deposition of silicone oil from the composition ofExample 6 (this example) shown in Table 6 The depositiontests were carried out according to the method described inExample 5 The dispersion exhibited a similar depositions toother hydrogels having similar silicone droplet sizesuggesting that the nature and characteristics of thedispersions may be more important in determining the level ofdeposition than is the exact polymer that is employed.?10152025CA 02265465 1999- 02 - 19W0 98/08601 PCT/EP97/0475140Table 6. Deposition of silicone oil onto piq skin fromcleansing compositions containing dispersed hvdroqelsSample No.Example 6Control (same control as in Table 5) Example 7. Illustration of the enhanced deposition producedby hydrogels.One of the benefits of using the hydrogel dispersions ofthis invention is the enhanced deposition provided to agentsthat are incorporated within their structure relative to theagents used by itself. This example illustrates the effect forsilicone oil. In particular, deposition of silicone oil fromvarious skin cleansing compositions were compared in thedeposition test described in Example 5. A set of compositionswas prepared by directly emulsifying 60,000 cps silicone intothe cleansing composition of Table 3 to make the droplet sizeof silicone oil about the same as those contained in thehydrogel dispersions of Examples 3A, 3B and 6.The deposition results of hydrogel dispersions vs.silicone emulsion alone are summarized in Table 7 anddemonstrate that substantial enhancements in deposition can beachieved by incorporating the agent within a dispersed hydrogeldomain. ?CA 02265465 l999-02- 19C6360l0l5202541Table 7. Enhancement of deposition of silicone oil fromhydrogelmSample No. Silicone Oil Deposition Level (b)Droplet SizeSi/S Ratio Si/S RatioSilicone Siliconein EmulsionsHydrogel Alone (c)Example 3B 2-30 Hm 7.l 1.2Example 3A 40-100 Mm 28.0 8.3Example 6 2-50 Mm 6.78 2.0Note (a). All compositions employed the surfactant baselisted in Table 3. The concentration of silicone oil in the_final composition was 5 wt% in all cases.Note (b). Deposition was measured by the ex—vivo methoddescribed in Example 5.Note (c). The same silicone oil were used in the preparationof the skin cleansing compositions by directly emulsifying thesilicone oil into the skin cleanser.Example 8. Preparation of hydrogel dispersion containinghydrocarbon oilsA wide variety of ingredients can be incorporated into thehydrogel dispersion of this instant invention. Previousexamples have illustrated several general features of theseAnother class of usefulSome of the benefit agents ofdispersions using silicone oils.materials are hydrocarbon oils.this class of materials are moisturizing agents such asemollients such as isopropyl palmitate and2—Ethylhexyl—P—petrolatum,sunscreens such as Parsol MCX (trademark,Methoxy Cinnamate). These examples illustrates the use ofhydrogels to‘J-" ‘?1O1520253035CA 02265465 l999-02- 19W0 98/08601 PCT/EP97/0475142deliver such hydrocarbon oils.Preparation of hydrogel precursor solution40% emulsions of different hydrocarbon oils i.e. 100%o\°petrolatum, a mixture of 50 % isopropyl palmitate and SOpetrolatum, and a mixture of 50 % Parsol MCX and 50 % ofpetrolatum were prepared by mixing 40 parts of the hydrocarbonoil to 60 parts of aqueous polymer solution which contained 0.5wt% Chitosan (first polymer) (Seacure 343 ex PronovaBiopolymer), 1.9 wt% Jaguar C138 (second polymer), 0.4 wt.%cocoamido propylbetaine and 0.25 wt.% acetic acid at 300 rpmfor 20 minutes using an overhead stirrer. The mixing was doneat room temperature except 100 % petrolatum sample. The 100%petrolatum emulsion was prepared by melting the petrolatum at60°C which was then added to the room temperature polymersolution and mixed at room temperature.Preparation of hydrogel dispersion by coextrusionThe extrusion process described in Example 3 was used toprepared 12.5 wt% dispersion of the hydrogels containing 100%petrolatum, 50%Isopropyl palmitate/50 % petrolatum, and 50%Parsol MCX/50% petrolatum respectively for examples 8A, 8B and8C. The surfactant system was the same as the one used inExample 3 (Table 3) except no Antil 141 was used in theformula. All these samples comprised noodle shaped hydrogeldispersions with diameter about 1000 nm.Examples 9. Preparation of hydrogel dispersion containingsolid fatty acidPrevious examples have illustrated a wide variety ofhydrophobic oils can be incorporated into the hydrogeldispersions of the instant invention. Another class of usefulmaterials are dispersed hydrophobic solids or waxy particles.Some of the benefit agents within this class of materials are?CA 02265465 1999- 02 - 19W0 98/08601 PCT/EP97/0475143moisturizing agents such as fatty acids, emollients, certain?152O253035solid sunscreens such as P hydroxybenzoic acid,agents such as triclosan,CA 02265465 l999-02- 1944and anti—acne agents such assalicylic acid.This example illustrates the use of hydrogels to deliversuch solid or waxy hydrophobic solids using a mixture of solidfatty acids aPreparation 022 grams ofNational Starch & Chemical),(Gelcarin GP9lauryl sulfatdeionized watmixture contastearic acidemulsified toacid emulsions the specific example.f hydrogel precursor solutiona modified corn starch (Capsul (trademark)4.4 grams of Carrageenan(trademark) FMC)were dissolved in 83.05 grams of11e (ex BDH)er at BWC.ining 50 wt% of palmitic acid and 48 wt% ofex.2lO grams of a molten fatty acidwas added to the above polymer solution andantimicrobialEX.and 0.55 gram of sodiumform a fatty acid emulsion at 60 °C. The fattywas then transferred to a Hobart Kitchen Aidmixer and mixed while cooling to form a viscous dough—likefatty acid emulsion.The emulsion comprised fatty acidparticles with a size in the range of l to 40 um in diameter.The above composition then mixed with an equal amount ofpolymer solut0.5 % of Chition containing 4% of Merquat 100 (ex. Calgon)osan (Sea Cure 340 ex. Protan) and 0.4 % ofIacetic acid to form a hydrogel precursor solution containingdispersed fatty acid.Preparation of hydrogel by extrusion14 parts ofcoextruded wiusing the metdispersion. the hydrogel precursor solution was thenth 86 parts of the liquid cleanser of Table 3hod described in Example 3 to form hydrogelThis dispersion consisted of noodle shaped gel?CA 02265465 l999-02- 19C6360l0l525303545particles uniformly distributed in the surfactant composition.Example 10. Further illustration of hydrogel dispersioncontaining solid fatty acidThis example is very similar to the previous one except thata different gel forming polymer was employed.Preparation of hydrogel precursor solution.(Capsul ex. National(Gelcarin GP9ll(ex BDH)22 grams of a modified corn starchStarch & Chemical),FMC)dissolved in 83.05 grams of deionized water at 80 °C. 210 grams4.4 grams of Carrageenanex. and 0.55 gram of sodium lauryl sulfate wereof a molten fatty acid mixture containing 50 wt% of palmiticacid and 48 wt%solution and emulsified to form a fatty acidof stearic acid was added to the above polymeremulsion at 60°C.The fatty acid emulsion was then transferred to a HobartKitchen Aid mixer and mixed while cooling to form a viscousdough-like fatty acid emulsion. The emulsion comprised fattyacid particles with a size in the range of l to 40 pm indiameter.The above composition was then mixed with an equal amount ofa polymer solution containing lO wt% of fully hydrolyzed(Airvol 350 ex. Airpolyvinyl alcohol solution (trademark)Product).Preparation of hydrogel by extrusion14 parts of the hydrogel precursor solution was thencoextruded with 86 parts of the liquid cleanser of Table 3using the method described in Example 3 to form hydrogelconsisted of noodle shaped geldispersion. This dispersion,particles uniformly distributed in the surfactant composition.?l0l52530CA 02265465 l999-02- 1946Example 11. Deposition of Fatty Acid from Liquid CleanserThe deposition of fatty acid onto pig skin was measured by aA S.O8cm by 5.08cm (2 inches by 2was first washed with about 0.35gas chromatograph method.inches) piece of pig skingrams of liquid cleanser for one minute. The treated pig skinwas then rinsed with water for 50 seconds. The skin was driedonce using a paper towel, air dried for two minutes and thenextracted with lO grams of heptane for~3O minutes. Aliquatsof the heptane solution were injected into a GC to determinethe amount of fatty acid deposited onto the skin. A controlsample comprised 7 parts water, 7 parts of the fatty acidemulsion used to prepare the dispersions in Examples 9 and l0and 86 parts of the surfactant composition listed in Table }(also used to prepare Examples l0 and ll). The amount offatty acid deposited from Examples 9 and lO, are compared withthe control in Table 8. The result demonstrate thatsignificant deposition of fatty acid occurs from thesehydrogel dispersions. Furthermore, as with silicone oil,incorporating the fatty acid in the hydrogel formulationsignificantly increases its deposition (compare Examples 9 andlO with control).Table 8. Deposition of fatty acid from hydrogel dispersionsunder conditions typical of skin cleansing.sample No.(a) Deposition of Fatty Acidpg/cm2Example 9 5.lOExample lO 4.2Control ('5) <0 . 5Note (a). All sample contained 4 wt% fatty acid and the samefatty acid emulsion was used to prepare all the samples.?CA 02265465 l999-02- 19C6360lO'__.\U12O2547Note (b). The control was prepared by mixing 7 parts of thefatty acid emulsion used to prepare Examples 9 and 10 with 7parts of water first which is then mixed with 86 parts of thesurfactant composition of Table 3.Example 12. Preparation of hydrogel dispersion containinglipidA molten lipid solution was prepared‘by heating 30 partsglycerol , 15 parts Cholesterol (Cholesterol USP ex. CrodaChemicals LTD),ex. Mitsubishi—Kasei Foods Corp ) and 7.5 parts stearic acid7.5 parts sugar ester (Ryoto S270 (trademark)(ex. Unichema International) on a l5O °C hot plate. The clearmolten lipid solution was then cooled to about 98°C and mixedwith lO parts of neutralized Aculyn 33 (ex. Rohm & Haas, 2wt%, pH: 7.5-8.0)Gelcarin GP9llhydrogel dispersion precursor containing Cholesterol.solution and 30 parts of Carrageenan(trademark) solution (2 wt%) to form theThe extrusion process described in Example 3 was used toprepare 17 wt% dispersion (2.55 wt% Cholesterol based on thetotal composition) of the hydrogel. Same surfactant system asExample 3 (Table 3) was used for the preparation. Depositionof Cholesterol from this cleansing composition was determinedin Example 13. A comparative example containing 2.5 wt%Cholesterol uniformly dispersed in a liquid cleanser wasprepared for comparison. The composition and the preparationprocess of this comparative example are given in Table 9 below ?1015202530CA 02265465 l999-02- 19W0 98/08601 PCT/EP97/0475148Tgglg 2IngredientCholesterol 2.50Stearic Acid 1.25Sucrose Ester 1.25Glycerol 5.0016.0Sodium Lauryl Ether SulfateGenapol ZRO (SLES)2.00Cocylamidopropylbetaine0.250.30Amonyl 380BA(CAPB)Jaguar C—13—SNaClWater and minors to 100%Pr r i nMelt glycerol, sucrose ester, stearic acid and cholesteroltogether on a hot plate. Premix the surfactants and the excesswater. Add the surfactants to the lipid/glycerol mixture thenadd the Jaguar. Preserve the system and pH adjust to 5.3.Adjust the viscosity using NaCl to 5000 mPas at 10s” / 25%)Example 13. Deposition of Cholesterol on skinThe deposition of cholesterol onto pig skin from cleansingcompositions was determined by the following method. 0.25 gramsof cleanser was rubbed 50 times on a 5x5 cm: pig skin that wasprewetted with tap water. The skin was then rinsed for 10seconds with deionized water and patted dry with a paper towel.3 ml of ethanol was used to extract the cholesterol from theskin for analysis.?101525toO\CA 02265465 l999-02- 1949The amount of cholesterol extracted from the skin wasdetermined by spectrophotometric method. The ethanol extractionwas dried at 80 °C oven. lOO Ml methanol was added to the driedcontent. 1,000 pl aqueous cholesterol reagent from Sigma wasadded to the sample and left for 5 minutes to react with theextracted cholesterol. The aqueous cholesterol solution was thenmixed with 500 pl chloroform and poured into microcentrifugetubes. Chloroform was separated from the aqueous solution bycetrifuging the tubes at l3,000 rpm for 5 minutes. Aftercentrifugation the top clear aqueous layer was pipetted intocurvets and the absorbance at 500 nm was measured using aspetrophotometer and a standard calibration curve to determinethe amount of cholesterol extracted from the skin.The amount of cholesterol extracted from the skin treatedwith Example l2 are compared with two controls in Table lO.The data shows that significant deposition of cholesterol wasachieved from the hydrogel sample of Example 12 as compared tothe two controls.Table 10. Deposition of Cholesterol from shower gelSample No. Deposition of CholesterolHg/10 cm2Example 12 48.4Control la 26.5Control 2b 21.1a. Control 1 is liquid cleanser contains 2.5 wt.% welldispersed cholesterol. The composition and preparation aregiven in Table 9.b. Control 2 is a liquid cleanser without containing anycholesterol. The amount of cholesterol given in the table isthe cholesterol extracted from the pig skin.?1015202530W0 98/08601CA 02265465 1999-02-19PCT/EP97l0475150Example 14A liquid cleanser containing 10 wt% of silicone hydrogel(5 wt% silicone oil of the total composition) and 90 wt% ofsurfactant composition of Table 3 with 0.3 wt% instead of 0.97%Antil 141 was prepared using the process described in Example3. The silicone hydrogel precursor solution containing 50 wt%GP911, 0.155 wt%Aculyn—33, 0.31 wt% polyvinyl alcohol (Airvol 540 ex Air60,000 cps silicone oil, 0.47 wt% CarrageenanProduct) and 24.06 wt% water was prepared the same way asdescribed in Table 3. The hydrogel precursor solution containssilicone oil droplets with size in the range of 5 to 60micrometers.Effect of the silicone hydrogel containing cleanser onconsumer‘s after—use skin feel compared to the liquid cleanserwithout silicone hydrogel dispersion was evaluated using theprotocol described below. The test site for this evaluation isthe volar surface of the forearm. Hand and forearm wereprewetted by holding under running tap water (30 °C) forapproximately 15 seconds. 3.5 grams of the hydrogel containingliquid cleanser was then dispensed onto the hand and theassigned arm was washed for 20 seconds and rinsed under runningwater for 10 seconds. The forearm was patted dry with a papertowel. The procedure was repeated for the other arm using thesame cleanser without containing the silicone hydrogel. Allpanelists were asked to determine their perception of after useskin feel. 7 out of the 8 panelists felt a difference in after-use skin feel and 5 out of those 7 preferred the skin feel ofthe arm treated with the silicone hydrogel containing liquidcleanser.?CA 02265465 l999-02- 19C6360253035 51Example 15: Preparation of hydrogel dispersions as skinlotionsThis example showed that hydrogel dispersions can be preparedusing aqueous solution composition suitable for skin careapplication. In this example an aqueous solution compositioncontaining 0.9 wt% Natrosol 250 HHR (hydroxyethylcellulose ex.Aqualon), 0.06 wt% Carbopol C981 (ex. BF Goodrich), 0.4 wt%Na3PO4 and 0.05wt% Glydant Plus without any surfactant wasprepared for hydrogel preparation.A petrolatum hydrogel precursor solution was formed bymixing lO parts of petrolatum (Snow White (trademark) ex.Penreco) to 90 parts of aqueous polymer solution containing-O.6 wt% chitosan (Seacure 343 ex. Protan), 0.4 wt% acetic acidand l.8 wt% Jaguar Cl3S at 60 °C,15 minutes using an overhead mechanical stirrer. The emulsion(Rhone—Poulenec) 300 rpm forso prepared contained petrolatum droplet with size in therange of l to 30 um. 25 parts of the petrolatum hydrogelprecursor solution was injected into 75 parts of aqueoussolution composition to form elongated hydrogel noodles using#14 gauge syringe needle. The aqueous composition containingthe petrolatum hydrogel noodles were then passed through ascreen having mesh size 200 pm to form the hydrogeldispersions. This sample contained large soft hydrogelparticles concentrated with petrolatum droplets and issuitable for skin care application.Example 16: Effect of Process Condition on Hydrogel FormationThis example showed that formation of hydrogel particlesdepends on the mixing device used to incorporate the hydrogelprecursor solution into the aqueous solution composition. Thepreferred process, extrusion/low—shear mixing process, providesa better control on the hydrogel particle size and has betterretention of water insoluble benefit agent inside the hydrogel?l520253035CA 02265465 l999-02- 1952particles.A silicone hydrogel precursor solution was prepared by mixing30 parts of 60,000 cps silicone oil in 70 parts of polymersolution containing 0.4 wt% Seacure 343, 0.2 wt% acetic acid and2.0 wt% Jaguar Cl3s at 60 rpm for 7 minutes using an overheadmechanical mixer. The silicone emulsion so prepared contained 30wt% silicone oil with particle size about l32 um.Two aqueous liquid cleansers with different viscosity wereprepared for hydrogel processing. These two aqueous solutioncomposition with composition shown in Table ll all contained17.5 wt% surfactants thickened with 0.4 wt% Carbopol ETD202Oand 0.4 wt% Bentone. The viscosity of these two cleanser wasl5,000 cps and 3,500 cps respectively and had a pH around 7.8.Two processes, a batch process and a coextrusion/in—line mixingprocess, were used to make large hydrogel dispersions in thesetwo liquid cleansers.In the batch process, 15 parts of above silicone hydrogelprecursor solution was added to 85 parts of liquid cleanser andmixed at 60 rpm for l5 minutes using an overhead mixer. Theequipment described in example 3 was used for thecoextrusion/in—line mixing process. 15 parts of siliconehydrogel precursor solution was coextruded with 85 wt% of theliquid cleanser through the two fluid nozzle to form elongatedsoft hydrogel noodles. The prehardened hydrogel noodles werethen continuously passed through a low shear in-line mixingdevice at the rate of 20 cc/minute to break the hydrogelnoodles into hydrogel particles. Two different in—line mixingdevices were used to break the hydrogel noodles. One is astatic in—line mixer with 0.64 cm (l/4") in diameter and 15.2cm (6") in length. The other in—line mixer containing twoidentical screens having mesh size about 200 um. Both thehydrogel particle size and % of silicone oil retained inside?CA 02265465 l999-02- 1953the hydrogel gel particles were shown in table 12. The resultsclearly showed that the coextrusion/in—line mixing process hadmuch better control on the size of hydrogel particles and alsoprovided much better entrapment of oil inside the formed5 hydrogel particles during the process than the direct mixingbatch process.10Table 11: Liquid cleanser composition of Example 16Raw Material Supplier low viscosity high viscosityliquid liquid cleansercleanserTergobetaine F Goldschmidt 26.7% 26.7%(trademark)Standapol EA— Henkel 18.0% 18.0%2L (trademark)Jodapon CI—ADH PPG—Mazer 5.8% 5.8%(trademark)DC3501 Dow Corning 1.0% 1.0%silicone waxBentone Clay Rheox 0.4% 0.4%Carbopol BF Goodrich 0.45% 0.45%ETD2020Glycerine Fisher 2.5% 2.5%Isopropanol 2.0% 0%Perfume Givaudan— 1.0% 1.0%RoureGlydant Plus Lonza 0.2% 0.2%DI Water to 85% to 85%?C6360Table 12: Hvdroqel particle size andCA 02265465 l999-02- 1954% oil retained of exampleléLow Viscosity High Viscosity LiquidLiquid Cleanser CleanserGel Size % Oil Gel Size %Oil RetaineRetainedDirect Mixing 392 um 68% >710 um 41%Coextrusion/ 230 gm 85% e140 um 75%Static MixerCoextrusion/ 305 um 88% 325 um 84%Screen

Claims (12)

We claim:

1. An aqueous composition comprising:
(a) 40-95% by weight of an aqueous solution containing 5-50% surfactant and having a viscosity greater than 300 centipoises; and (b) 5% to 60% by wt. of a hydrogel composition comprising:
(i) 0.1 to 30% by wt. hydrogel composition of at least one polymer soluble in water which polymer is insolubilized when placed in the aqueous solution of item (a);
(ii) 0.2 to 30% by wt. hydrogel composition of a polymer soluble in water, and soluble or dispersible in the aqueous solution of item (a); and (iii) 1.0 to 60% water insoluble benefit agent entrapped in a network formed by (i) and (ii);
wherein the particles of the benefit agent (iii) have particle size of 0.2 to 200 micrometers;
wherein the hydrogel is greater than 25 micrometers;
wherein the size of the hydrogel (b) is greater than that of the benefit agent, and wherein the hydrogel comprising composition is formed by injecting a hydrogel precursor solution into the aqueous solution or by co-extruding the hydrogel precursor solution in the aqueous solution.

2. A composition according to claim 1, wherein polymer of (i) is insolubilized, when contacted with the aqueous solution of item (a), by thermal gelation.

3. A composition according to claims 1 or 2 wherein said gel forming polymer is selected from the group consisting of gel forming polysaccharides, gel forming proteins and thermally gelling synthetic polymers.

4. A composition according to claim 3 wherein the gel forming polymer is selected from carrageenan, agar and gelatin.

5. A composition according any one of claims 1 to 4, wherein said gel forming polymer is a synthetic polymer selected from the group consisting of N-acrylamides and homo or copolymers of polyacrylate or methacrylate containing polymers incorporating an acrylic or methacrylic ester of a long chain branched or straight chain alcohol.

6. A composition according to any one of claims 1 to 5, wherein polymer of (i) is insolubilized, when contacted with the aqueous solution of item (a), by precipitation or coacervation, wherein precipitation or coacervation is caused by a change in pig, and wherein polymer (i) sensitive to pH of aqueous solution is polyglucosamine.

7. A composition according to claim 1, wherein precipitation or coacervation is caused by a change in electrolyte concentration, wherein polymer (i) sensitive to electrolyte concentration of aqueous solution is selected from polyvinyl alcohol having MW greater than 13,000 and degree of hydrolysis 78% to 100; and hydroxyalkylcellulose.

8. A composition according to claim 1, wherein polymer of (i) is in-solubilized by cross-linking with a cross-linker present in the aqueous solution of item (a).

9. A composition according to claim 1, wherein property modifying polymer (ii) is selected from the group consisting of:
(a) carboxylic acid containing acrylic polymers;
(b) nonionic polymers selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, modified corn starch and hydroxyalkyl cellulose or hydroxylalkylmethyl cellulose; and (c) cationic polymers.

10. Use of a composition according to any one of claims 1 to 9 in a personal cleansing or skin care cream or product.

11. A process for preparing an aqueous composition comprising hydrogel particles having the following composition:
(a) 0.1 to 30% by wt. hydrogel composition of at least one polymer soluble in water which polymer is insolubilized when placed in said aqueous solution;
(b) 0.2 to 30% by wt. hydrogel composition of a polymer soluble in water and soluble or dispersible in the aqueous solution; and (c) 1.0 to 60% water insoluble benefit gel entrapped in a network formed by (a) and (b);
wherein said particles of benefit agent (c) have particle size of 0.2 to 200 micrometers;
wherein said hydrogel is greater than 25 micrometers;
and wherein the size of the hydrogel is greater than that of the benefit agent; wherein the process comprises the steps of:-(i) dissolving polymer (a) and (b) to form a polymer solution in water;
(ii) dispersing component (c) into the polymer solution to form a hydrogel precursor solution;

(iii) formulating an aqueous solution comprising 40-95%
by weight of an aqueous solution containing 5-50% surfactant and having a viscosity greater than 300 centipoises, such that first polymer (a) is not soluble and second polymer (b) is soluble or dispersible in the aqueous solution;
(iv) combining the hydrogel precursor solution and the aqueous solution by injecting the hydrogel precursor solution into the aqueous solution or co-extruding the hydrogel precursor solution in the aqueous solution to form elongated hydrogel noodles which form when the hydrogel precursor contacts the aqueous solution, the noodles being sufficiently rigid to entrap benefit agent yet sufficiently soft to readily rupture when applied to a substrate; and (v) breaking said noodles into particles by means of a mechanical mixer in line mixer.

12. A process according to claim 11, wherein the insolubilization of first polymer (a) is caused by thermal gelation, precipitation or coacervation, or cross linking.