GB2398499A - Two layer capsules - Google Patents

Abstract

A delivery capsule comprises an enclosing wall (10), the enclosing wall comprising an inner layer (30) of a first material and an outer layer (40) of a second material, the first and second materials having different solubility properties, with one or more portions of the inner layer constituting part of the outer surface of the capsule by the creation of a flange (18). When capsules in accordance with the present invention are added to an appropriate solvent, the solvent contacts both the inner layer and the outer layer of the enclosing wall of the capsule which may behave differently under the same conditions. It is thus possible to exploit the differential solubility effect which exists between the inner layer and the outer layer to control e.g. the rate of release of the contents of the capsule and/or the temperature at which said contents are released. The inner and outer layers are preferably polyvinyl alcohol (PVA) of varying solubility. The capsules may contain bath oil.

Description

Field off Invention

The paw Mention t#lates ID a delivery Pablo, tbt id 8 capsule defined to rebill and protect he confab Ural inward die of defray or comedic of Delia art: adieu_ at which pout the capsule contend ue reload.

Delivery capsules are well Icnown a convenient Mae Fir cony-g of a Maw.

such, day find pac application in numbed and dilate fields including the delivery of Rely rmerod dice of,rical and dietary supplements, and doses of ccnedc prqons em fragrancod oils Sated within a sod water-1uble film modish Convey, the capsule Will of dewily c_des leave been formed fit dcrired gnaw However, m view of animal osacerns Ad the fear of animal relied diseases such as Bovine Sponpfonn Encephalathy (BSI!), be popular of water soluble gelatin subtitle matena4 which am nones demigod, hi WO 97n5537 describes cake produced from Proximal derived materials impeding waters soluble films such as polyl alcohol (PVA). The capsules desenbod in mid docked dissolve and release tear cone accg to the solvability of be fihn Serial of the tubule wall I.G if a hot Soluble film used, the clubs will of dissolve and rdeasethdrcoDtents in hot water. Alec_ of wO97DSS37 uefomod fiom nvo films of lilac menial with each film faming cape 11( Ed with two halves scaled together to roan complete clc .

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According to one "poet of the pat invendon, there is provide a delivery capsule contriving an enclosing wall, the enclosing well compr;. - g an innerlayerof a fiat mad "d an Odor layer of a Ed misI, the Bet and second materials having did solubiy pe4, with Ate or more portions of tlte inner layer og part of He ogle oftbe coo.

The layer Iho out 1 of the enobamg wall topper form a complete encode around flee oo oftho CtQ The He may contain a wide range of madders in 1ho form of.-, liquids, solids (fig. pi, powders etc.), and Michael theroofe g; dustier Ampler of auibble materials lbr w in the Maples deombed herein include dn-, mom-, powder, oils, coedc pit bug ddivey by_ dim and told pione en:.

The outs Menace of the He is confided in part by die irmer 1 of the fi medial and in pm by the ouch layer of the second mriaL the two mob braving did solubili pe One or mare port of the inner layer thus cotituus part of the of suffice of the code. This mew the the outer layer of Me "CIOdDg Wed is bled llefo' gioas of the ins layer Be exposed to the eland -ental Cottons expaicooed by the Sophie.

In use, when cues in accordance with the prams invention are ioU8Dt inn Contact with an Via. solvad (edge by big added to an ppprapnate solvents Epically wow (lough other Solvay may be u#fielly employed cog. sIcohole, aqueous alcoholic mixture, digestive juices etc.), the solved content both the lo ad the outer laya ofthe cocbg Call oftbe c= The fi-and oooond m. of Ihc timer layer and the outer layer repoively may bode diffcry untie die cane code due to Air differed solubil' Claus, it is poadb}e to exploit the kfferenthl solubiN effect Chicle exists between the layer and the outer layer to oonlrol e.g. the me of release of Me comma of We capsule and/or the Opera at which the contain He rely Moreover, u He outer surface of the capsule is tromped pert by the moor layer of the flat material and in part by He outer lays of the aecond me different goomeia of he are possible.

has been dot hacin above, the outer 1e-of the Prolong wall is incomplete Id contr-,- He inner layer of He enclosing wall may be i-_ or complete, Ed prefasbly is complete In Male cues the inns layer i' Gb Lyrical or ovoid, and may be Mod Tom dam haves of an slope client joined togeth by a cimumfaentid flange at Ode paipy.

one pefenod embodiment herein the culo of a generally Optical or oYsI sluice, having À cimumhtial flange ext Em its of surface. The capsule thus simplism two similar hemispherical or hemiovoid halves hang at thdr penny a circumferential fl-go, each half inclg a Ad inner layer and outer layer with the No halves bum Fled together via the Bangea to find the complete capsule. be this picubr anbo_ of a prepared he in bw win the pro invention, the inner layer ctiho part of He outer To of the clue at the irmer or cent region of the &ngepai. A.

Such capsules may be conveniently made by the technique and ppu described in WO 973SS37 Ovid possible minor modification The nueorh of the inner layer author outer layer may be supplied in the forth of ribbon-take films, or sIternauvely can be readily numulicd e.g. be, extrusion Sum solution a cuddly preferred method, He inner layer of a first material is Flied to the outer hyer famed fiord two nbbalike films m the Ibrm of a VifiCOW solution via elusion, generally og extrudes bare modified with fine applicator controls nor accuracy. The viacour achaion dou}d be applied co the outer Lear in ppmpriate amok The mount of soludon applied is gmedly coollod to pmr complete dissolution oftbe aver layer savor the Fiction of a film of insufficient to paced mu À ooze Coke: amount am be ratify debanined by experiment bt order to obtain good lion by the inner layer and He ouch layer and Arm a bow behvwa the layers of tle straw, Sty the amount of vu solution applied to the cuter layer u such that the outer lays softens and partial dissoludan thereof is "cYI Ions, this effect also fiititatos the formation of a capsule of a defile Cop Typically, the first At of the inner layer i' Plied a t2% soludon in water to each film forming the outer layer at a thin of about 2S to about go prolabor 3S gems The out layer generally absolve a pi of the solvent, typically water, him the solution Additionally, some of tho coldest In eve nude may en 1 in the &'mution of a did, inter layer. In ord-b the kilo Shoos ofthe clc toolhor, it is debb tint not aU of the solvent firm the sold is absorbed by the out. lay. onpo prior to 80 layer partially mIvabd and thy. The come halves can thus be Ed of Me iYC en ct of the Plb, solvod imps layer.

Typically to mea" Drippy solvent desonbod in WO Y73SS37 are replaced with maces for,g sobs of inner layer of a fist material to the upper He pled by the oula layer of a sowed mat-. ial, preferable, at aD pppropnate locadon Bream of the encuton unit.

In an He of capsule Hog to the prow invcatian, the capsule compnces oomptetc inter sayer of a find material berg an ilete outer layer complying one or more pogrom of a soloed medial impeding one or more He, We or spaced lhe miter layer thus constitutes part of the outer surface of the capsule in the region ofthe He. We or es.

The layer of the hm material Ad the outer layer of the Ed material may be chemically alike but mar not be identical in terns of grade, or allusively, the materials may be chanically dint.

The to of So outer layer of the iDg HI may dipped upon a numba of factor indudg the node of He In, the intoned use and purpose of a pendular Chile and its size Typically, the of the outer layer nay By between the wage SO mi:roDs to about 150 mock, sod "feebly about 100 microns Typically. the to of die timer layer will be chow 80 to en tile Me at the eden of the capsule are recessed, but genuinely varies between S mind to about 30 microdot Typically, for pencil punnet, the lust and accond materide of We inter layer and die Outer bycr Lively, hew dill solubili i" Tom - # mother m Ape-pies solve-, I, Without 6 celtld.n Split-old ot Lame GO ooboby, Podm Or die first materiel "d cooond material of the endowing washed ate . cold wan soluble, mom nor soluble or ltot water solubic Me tam "cold Or combo" used hew me material which dissolves at a t_ab in the He *0 about 0 ( to about 30 C. 1O em "W8m' Wow solubles 6 beDDiD _I.Wh;Cb it;-OIVe at a 801Ie id the range from about 30 C IO 60 C and the HIS Water BoIUbIe.. Wed 1 McCoy a m8l Which dissolves at a IaUP=BUDe. 6tPC

Sly-ble example of miale sohible in wet-(hot, wam or cold) if POIYY;DYI alcohol (Pow cognates, popyl mey1 cellulose and polyethyleDc oxide; or mixhtlleroof. a...

Any of the above described mandible may be Stable fior use He Mar layer Dee capsule.

Her suitable madman for Be omer layer of eatables herein include none soluble maiale such porolaceone and ginised Ah based mater)" A suitable material for the Her layer is PVA po - Ply admixed win eyetbylene oxide "d qllypcisod fig. with glycerin.

The premed menial for bow the Her layer "d the outer layer of e_ herein is PVA. wash is Libby in a wage of Odes, vapor, erg. seed did Ip_ firming bind or Ate Made is Relation solubili6-and _. AdtionaUy, such _eiab are ilabk Cal id the Rim of ribbolibe films or CAD be readily _lufctured i e. g. by extrusion from solutes An ypmpnate material ID too form of a film or solution can be readily selected had regard to the Intended use, capsule contend and desired Cyprus pities.

Examples of stubble fi - Uteri" for the inn. layer of a come berate include: 1. 12% Mucous solution of Mowdol 28:99 hot water soluble filler hydrolyzed PVA.

commorcilly awilablc few Hboch, G-moor. optionally It oiL typically

vegetable oil.

2. 12,C aposus 80hi" of 1 - vim 30:92 warm soluble, pimply 1 - mlysod PvA comnchLb Ok from Boochd, Away.

3. 12% aqueous aolubon of Goal GLOS cold water soluble, pi hydrolyzed PVA (oppose Goshei) c availably 10 Bnb 7hdere Ed Shipped 429 Rim Road, Soul Dippy, 1hQ UK 4. 12% aqueous 0h0n of Gohl GH2O, partially llyt EVA (Nippon Goshei) S. 12% aqueous solution of Gohol GLOS (as above), plicised with I. 6. 12% aqueous oodution of cold moor soluble rem 70:30 Mongol 28:99 "d Gobsmo1 GLOS.

7. A solution of 80:20 who PVA "d polyethylene oxide, plod by diasolvg up the PVA and polyetllyicoe oxide together id produce a solution which Will gamely; form a homogeneous Mar layer And prominent volubility pmpades throughout Suitable sooond materials for the outer 1 - r of capsules bed nc1-"A film Via] commercially available fir ecle mom his CraR, 407 County Line Road, Gay, Diana, USA; Nippon Hi from British 1 and Shims above; Hello, Jean and Cast Film Technology o4 9101-t Burned Road, Intend c, 11EDOll. USA Suitable films arc available in He of grades (-Opining a Eagle type of PVA or blends of PVA rains), tbi and big dimming speeds of sohbib. An Ike fIhn can be ramp selected hying regard to the capsule type and deeded capsule size For example, PVA Fins of a rig betides 70 mice and 120 my are Apical mod.

Nos-Iimidag trample of suithbk fibns for heroin ineludc He Sol me milable lion a8 C - R 0 - is a T - de Marl;) as exemplified by Nosed M7030 "d Monoso1 M8630 and the Hi-Seloo Loge available firm NO Goshd (Hi-Sd is a Trade Ma*) as exemplified by cold wator mIubk Hi-Selon C200.

Ely using an sayer of a find Medial and an out layer of second m-; haying diffract cohebility poverties, it is potable to Ago far Russo of the cot of the Creole under dill oonditiom. Genially. at least one ofthe miab of He am-bow or outer layer of the wall is chosen so u to be orb_ Mohawk Theo 1br exile, the delivery come is _-d 111 a sole-, pudabrly water, of a prowar Operate or coed to digeiwJuica. Ihw, in to He red of Me cone of the capsule, Me at led one other martial of the "closing wall chow bevin, g an Cab volubility Rich will came it. dlrc Hen Me cllivoy capsule iecxod to the same conditions Obese, any particular ddivety capsule will be formed dam at least two such mad of diltial sohbiy.

The layer of a flat maternal may be 1e soluble than the outer layer of a second may, e g. tvbich My Diablo a capsule to be en wa11 wow dissolves at a diffiamt rate acmes its tbicbese.

For instance, a Poe-e to cold water of a finished capsule compg in layer of hot water soluble Mongol 28.99 ((I) above) and an outs layer of cold watt soluble Hi Selon C200 film in cold water, will remit in the outer layer of the eoclog well of He Capote bang dissolved leaving the ins sayer intact Typically, use of a thin (e.g. S mice_ to about micron) hot wet" soluble inner layer, is likely to result in the Inca bycr rupturing under the weight of He contents of the c4auk, thereby rdeasiqg "id cantata. Follows no, the hot water soluble inns sayer _a11y remains 1b in Even, the addidon of a propordan of cold wet soluble such blend of 70:301iol 23:99 and Gohol GLOS ((A above) to Mowiol 28:99, wi11 produce moor Her Rich Ton Spy fiagma" it of - - by ink.

Dqd on the intadod use of capsule, it is Bible to release Me content. of the capsule from an layer of a firm martial whicb more soluble than the outer layer of a spoons memorial. Qua, pre - 'ed enodim" ha - , the inner layer of the fi - martial is more soluble than the outer laycroftbe second mia.l.

Advantageowly therm - , the pow iDVa fi.ci8 the - Don of deduce to be name cable and robust Ha ha hit been pbk Ed which conveniently prevent lo_ repose of the cot of tile coo upon Dali Forge, mmufachg "d pa' C_ release thdr contents in cold or warm water He greenly more Idle to dissolution upall haDdlh4 HI minim dlg of Me cow before use apreb14 as Acids contact Tenth sown such sweat on the Ends c" Pierre Me of He so_. 10_4 atoage, PI and hndlfg of colobk cape is there difficult to acbiere if the tbicb of the Capsule wall "d its solar are the only faction in the of release of He Capote contents (i.e. oolubilibr rate). Dqn.g on the iintded use of 8 came, it is Bus possible to obviate these dificulffa "d provide a Capote which is Epically water soluble and displays greater e to degradation of the ouch layer of toe enchdq' wall of the Auk ppon contact W!i Ant of e g or upon ill contact with _re, Ret cooJlsbly (Gg. at a desired me) is cones Mar;.a con of Abut e.& m cold or warm waler.

This may be achieved to good eflict by employing an outer layer of wand For soluble PVA film and inner layer of cold water soluble my such as Gobol GLQS (3) above). Use of Mowiol 30:9Q ((2) above) the Air layer of an encloemg wall iDStad of Gobsmol GLOS, will produce totter layer of a c_ which is more rest to dissolution in cold water Al Gohol GL(K, but lea resistant than an imps layer of Mowiol 28:99 (1) above). Lived, use of Gohol GH20 (44) above) as the layer will produce an inner 1 which is lea soluble an inner layer of Gambol GLOS.

One Annoy favoured my 1; the near 1 of capsule, dedgned tD Mete its contends yin expose to cold ergot rent Addling, is a colt water soluble 70:30 bland Of Mowdol 28:99 high 11ro kvd PVA rem fram Hoec - , Germany and Gobool GLOS PVA resin firm Nissan Goshei, Lynn. enables He DO - _ of rob" capsules (in pad ebb of a cube herons, which may be rear aalod good en the seal Spicily bang oomph by the ins 1ayere oth-'iioular haves which Marc been joined together to lam a oomple" CRAG The seal 0ea.11y has thicken of about I O manna The utter layer of a firm mat "Thor Be outer Lear of a second my be colored with my wobble oozing Ant em for aesedc or Bali-pm Nat lay-Ad ours Dyer may be the sane cobor or dimmest callous Id a preferod bract' a cab m asoordce with the;nvon codes two Amid Ives, tale berg st in payday a cb 0e a_ a suppose And later of a fib martial which more aotubk (epically in wad) an of later of a second my, the No halves lying 1 to Flab Poem a oompbte capsule.

The print invention bus provide a water soluble chub comprising two la' halved each balfiscludg an merhyerofawersolubb fiat my bad of e (in a coollot He layer) u4 - imported upon an outer layer, with the inner 1 day the release of the Donuts of the qpd4 cog rate of teleuc "d/or In_ of recede, bu4adettly of the outa layer. 1 may be achieved by careful sebodoo of He fonnshtion of the inner layer "d the to at which it plied. TycaDy, the a of the two Hal of die cork are Deficiently adhesive to He robust chew why Ret tossed to dam a complete capably Thus, cola m. be dmied which are more it to iocidelltal exposure to water and rough handily yet are positive to the extanal omditia" to which they are ergot.

In use such a capsule is added to a Quibble solvent, Spiced Per, of _ he to the sohbilf0 of he layer of the Fiat material He c_oleasa its contend upon pay or compote tusoludon of the for or cereal Ron clothe He pimply oibntod by the ii - er 1 in Ability of the candle to olUtioD is effectively bolt into the saL The outer 1 of Be capsule auto ire, Mite the rebater of the oontts of the cable. This may be advantageous certain appion4 where d'on of the of layer into several smaller fifteens;B not deBiabh Generals, it is unable to employ optional ingrodi in the imps layer which may prey-t efficient soaring Hereof. Such ink are rashly JO by a person dulled in he licker, it bee also been fiend that the "hue of the cod to be encamp - d the aclog 11 may deo affect tho ability to HI the Layer at its periphery and thus fond complete cow Far Anglo, contend which fallow attachment to the hydrophilic deos pr_d by PVA, ply Ally hlrood PVA, coat PVA Picky i prey sepals of We Inter "d law infusion of a complete chow 0 o.g. vegebk oil in vat s may Lila be Ed to PVA to At the cat Ming hqc-thntb and _Ig the layer Red at id pimply. I In a fisher aspect of He prt invasion, a diffract "Marion of material for the inner layer i,e. condoled release layer Allied to each half of the two similar halves oonprig tbe outer layer.

Ibe ce' may have a sanely of shoes and arises why ddenned by the shape of the would employed ma/or the desired appL&:atico. Generally, the c spy or oval, but more elaboo Fox o.g bued on licit, Bowers or Ant capes may be produced. Typically, the out and thus the timemiane of the capsule my be varied to suit the my purpose of the come, win a typical diamot of a come bong m the range lioen about lOmm to about 40mm "d preferably about 26nm.

The comes ofthe present invention find nuenemus applicant with, for epl a topical coedc or personal applicatian being the encapsulation of bad oils to produce cycles inflow to be wed in the bath hying im>vod hating and rapid dissolution Few, a Apical household or domestic application He aan of dose of domestic or hold product. - The mendon win be fi - a described, bar way of ilkion, win reference be Me accompanying dray in which: FiBore I u a Tic sock view of a delivery Cole in accordance Ant We present invention.

Refiring to the fig, Fey I illusory sc ceDy goneratb ovoid delivery He 10 idDg;Dl! I1 12 m the form of h-similar half ably 14 and 16 each of gear baiovoid fam The half shells 14 "d 16 ofthe mclodag wall 12 each compose so Allayer 30 of a first mat and of layer 40 of a cocos menial. The moor 1 30 and ouch layer 40 of Me aclog wall 12 together form a complete He wound the ante 20 of cable 10. The fief and second mafia have did solubir pmpafies firm one amber, with one or more pordons of the imer layer 30 oombbg pant of the outer surface of the capou.le 10 at He 18 in the inner region ofthe flangehey.

The half 11s 14 and 16 sealed yodeler to film a oomp1do He lo Y #al SO on flange t8 vbicb Ida cha_tially fmm tlegmerally ovoid density capsule 10.

The outs layer 40 of a second material and the Inlayer 30 of a fim material of the enclasp wall 12 may be chemically Sac but may not be the sane in terms of grade, or altaaadvely, the materials may be chemiedly d. t, deposing on the deed proposes and intended see ofthe came. flower-, each layer ha different aolubiNty pertice from the other. lids roquirent may be exploits when it is dedrabk to fixate a come 10 which is genealtr robust, and cable of for expk, being handled md stored to prevent pc Rowe of the compote 20. A came these pmbes can be provided the out Inter 40 yes soluble tam tic ion-1 30. Far exempt, the ouch layt:r 40 a polyvinyl Tool me-in Lob soluble in yak solution at t2 temper above 30 C and Me Lear 30 compress polyvinyl alcohol resin which dissolves in aqueous solution at Area above S C.

Gem By, delivery c-tile 10 may be designed to micase id cone 20 Muse under different condido" "d aRer Dot time Id For exile, contents 20 may be relasod to seal SO whoa the cqsulo is added to a soibbk silent, Epically water, upon diesolutiso of all or part of We Inter 30. JUtvdy, seal SO nosy reles#, flee cue 20 when the "or 1 - r 40 dissolves upon the capable berg added to a ibbk solvent Al the seal no as a result of not bang able to sup the weight of con 20 wit the comparrd thin imp Lear 30.

Ike following chimps to Bive a specific illusion of this ideation but it is Dot ID any way invaded to limit the scape of the invasion" A good qudi dewily capsule combining an aquaria "d oil fin was prepared as shown in Fiddle 1 using the mood "d bus Iy as deathbed in WO 9MSS37. The ddivoy cues so gay _d release of their aborts Upon He to incident moisture and sweat dung Hug, yet rapidly released their contend upon en he to a volume of worhewng a Lab. above 5 C. \. i

The outer Layer of be capsule was Fox fiom two films of IOTA WORD water soIabk polkas alcohol, soluble in wok at es He 40 C. To the films at postings 28 and 30 ilhsed in Figure 1 of WO 97t3SS37 i.a to Be inner Ace of each fibs, was applied via Exxon, udag cold adbedve en bum modified unto fine applicator Control For accwy, (such 88 0 -- by V8lCO, CinciDn-, USA), a view- BOIUtjOn prep - ad dO8Cnbed blow: A 12% solUdm Of a 70:30 bond Of hnviOl 28099 EVA redo aVaIbbk fmm HbOCb" GCImDY and Gobs GLINTS PVA new available firm NiPPOn Gosba, Japan Was Ed bed we When sohdon ck hi was removed and Ibe blend dbwad to cocI.

The vacow sohffion applied lbe films in u' Tale amount to cam esflady and partial dissolution of tle filmy Tally, the solution ppliot to the film Aiming He AL bya of a cue at tbidne. of But 35 gAm3. The lipped solution Lo. thus dome the dyer of the c_ He Rich p-ally dimly-m water down to À Tame Of about S C tho moor or cent of the flange peNphay typically eleadog the codicils of fflecaple.

The films win Scow sohaion Spud b the Ace, bevin,g aL-rod some of the to equate, were then supplied b encubdon twit, opium deacon m WO s7nss37, we don of an agusow oil fill to be were minted bets Be layers The of Eyes of die film mutable having u4 so meter layer was bonny into opposed Cook halves axdainh tho aqueous Toil fill. The apple halves ware Den ht together and sealed, the seal bang created by the adhesive emit of He partially solvated. layer applied to the outer layer. The finished capsules were dim cut from the fibns and Or ddot or force dried to remove use arced *am, before being plod.

consul preparot as dcnbod above, wee_ pi In wat. st of about 20 C, the queow and oil all Tot fiom the capsules within about 60 seconds, lbilo He of Ever moo the capsule seal formed by the Her layer al the inner or central Upon of Be forage periphery. The outer layer of the campus reman subhally undissolved in solution.

Capsule are Bus vidod, which Idly release their contend under daired Ed Bale ooc/ditioru' he m- AYE wa-, yet me Be dough big or e_e to mcidenl moiety

Claims (11)

1. A delivery capsule ciq 0clodeg wall, tie enclosure wall comprising an

inn.

layer ofa lit material and outer lyerofa second menial the fiat and second my having different volubility pimples, with one or mare pordone of Me imps byer coning part of We outer entice of clc

2. Wit capsule to clay 1, whey the USA 143rerof1he mcl wall complete and the Outer layer ofthe cock wan is inplae

3. A delivery capsule D8 to cay 1 or 2, wb the cqaulo con'-es two Mylar abased halves baaing at their pdphcry a cicutial Up, each half including a layer and out. layer Cilia the heo hove bong Id together via the flanges to tome the complete coy

4. A delivery capsule "cording to clam 3, the tow Am" dyed halves are mihdcal or hemiovod

5. A delivery capsule fig to clay I or 2, whiten the capsule c a compute inner layer of a lint mdedal Bering an ilete out= layer comprising one or more portions of a second material including one or more _4 gad or ppsoca.

6. A delivery capsule to any one of the procodiog claims kelvin the inner layer of Sat material and the over Dyer of a second materis1 arc chemically alilce but It identical m teens of yule

7. A delivery capsule &g to any o" of the pi clans, WbaeiD the inner layer of a Fist ml and He ouch 4 - of a Id materid He cbemiceLly different. /

IS

8. A deliverer capsule Bonding Her one of the procodg clam', c. the Srst second dials Eve dint aolubility properties Gem one anon in water.

9. A delivery capsule n,g to any one of the ping cat wheeler flee enclosing wall comprise an inner layer of polyl alcohol, optior; fly admixed witty polyeykne oxide or glance, "d mixed thereof.

10. A delivery capsule to any one of the pr_B clam, USA. & encbehg wall comprises an outer 1-r of a misaim aolectod fiom Polaroid alcohol.

Mona - , hyyl methyl cellulose "d poIyeylene oxide, ormixbc Woof. i

1 I. A defray c_ dir,g b claim lo, win the lo" - 11 com. mes an outer layer of polyvinyl skoboL 12. delivery cable according b any one of the pig claim', a he layer Of polyvinyl alcohol is le" soluble the outer 1 of polyvinyl alcohol 13. A delivery capsule according to any one of claim 1 to

11. wherein 11;. : aer layer of polyvinyl alcohol ha more soluble than the outer layer of polyvinyl alcohol.