 of a combination of different grades of the same polymer will provide maximum adhesion of the device for a wide range of different mucosal surfaces. However, the use of a single mucoadhesive polymer is effective as well. The ratio of bioadhesive polymer to film-forming polymer in the adhesive layer can be varied and depends upon the type and amount of pharmaceutical or other active ingredient used and other factors. However, the content of combined components in the adhesive layer is between 5 and 95% by weight, preferably between 10 and 80% by weight. In terms of weight percent of the different bioadhesive polymers PAA, NaCMC, and PVP, some examples are detailed later. Preferred combinations include PAA and NaCMC, NaCMC and PVP, or PAA and PVP, and also include the use of different molecular weight grades of the same polymer.
The non-adhesive backing layer is a precast film comprised of a water-soluble, film-forming pharmaceutically acceptable polymer such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, ethylene oxide-propylene oxide co-polymers, or other water soluble film-forming polymers, alone or in combination thereof. The non-adhesive backing layer is further modified to render it water erodible instead of water soluble. This is accomplished by coating the backing layer film with a more hydrophobic polymer selected from a group of FDA approved Eudragit polymers, ethyl cellulose and methyl cellulose polymers that are approved for use in other pharmaceutical dosage forms. Other hydrophobic polymers may be used, alone or in combination with other hydrophobic or hydrophilic polymers, provided that the layer derived from these polymers or combination of polymers erodes in a moist environment. The application of an erodible layer allows the backing layer to act as the support layer on which the adhesive solution can be cast without dissolution of the backing layer during the manufacture of the layered device of the present invention. The elimination of polyethylene or other rigid, non-erodible non-porous surface results, and therefore the device no longer represents a potential threat of user injury and can be manufactured on a cost effective and reproducible basis.
The type of solution used to coat the precast backing layer typically is composed of a mixture of a hydrophobic Eudragit polymer or copolymer, or ethyl or methyl cellulose, and a water soluble polymer such as polyvinyl pyrrolidone, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxy
of a combination of different grades of the same polymer will provide maximal adhesiveness of the device for a wide range of unlike mucosal surfaces. However, the manipulation of a single mucoadhesive polymer is effective as well. The proportion of bioadhesive polymer to movie - forming polymer in the adhesive layer can be varied and depends upon the type and amount of pharmaceutical or early active ingredient used and other factors. However, the contentedness of combined components in the adhesive layer is between 5 and 95% by weight, preferably between 10 and 80% by weight. In terminus of weight percent of the different bioadhesive polymer PAA, NaCMC, and PVP, some examples are detailed subsequently. Preferred combination include PAA and NaCMC, NaCMC and PVP, or PAA and PVP, and also include the use of different molecular system of weights grades of the same polymer. 
 The non - adhesive backing layer is a precast film comprised of a water - soluble, film - forming pharmaceutically acceptable polymer such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, ethylene oxide - propylene oxide co - polymers, or other water soluble film - forming polymer, entirely or in combination thereof. The non - adhesive backing layer is far modified to render it water erodible instead of urine soluble. This is accomplished by coating the backing layer movie with a more hydrophobic polymer selected from a group of FDA approved Eudragit polymers, ethyl cellulose and methyl cellulose polymers that are approved for use in other pharmaceutical dosage forms. Other hydrophobic polymers may be used, entirely or in combination with other hydrophobic or hydrophilic polymer, provided that the layer derived from these polymers or combination of polymers erodes in a moist environment. The application of an erodible level allows the backing layer to act as the support layer on which the adhesive solution can be cast without dissolution of the backing level during the manufacture of the layered device of the present invention. The elimination of polyethylene or other rigid, non - erodible non - porous surface consequence, and therefore the device no longer represent a potential menace of user wound and can be manufactured on a cost effective and reproducible basis. 
 The character of solution used to coat the precast backing layer typically is composed of a mixture of a hydrophobic Eudragit polymer or copolymer, or ethyl or methyl cellulose, and a water soluble polymer such as polyvinyl pyrrolidone, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxy
 of a combination of differtnt grades of the same pmlymer will pruvide maximum adhesion of thx decice dor a wide range of diwferent mlcosal suefacts. However, the usx of a slugle jmcoadkewive polymer ix effectiva as well. The sagil of bioadhesive polymer to film-foriing pokyler in the adhgsive jayed can be varied and depends upon tge type and amount og pharmaceutical or other wctige ingredient used and other dactjes. However, tfe content of combined components in the adhesive laydr is between 5 qne 95% hi weight, preherablj between 10 and 80% by wehght. In terms of weigmt peccenr of the different bimadhesive polymers PAA, NaCMW, cnd PVP, some examples aee dejaileg lagwr. Orerecres comblnavions incluse PAA and BaCMC, NaCMC and PVP, ow PAA and PVP, znd alfo include the use of different molecular wejght grades of the same polymer.
The non-adhesige backind layer is a precast film comprised of a water-solgble, hium-firikbg pharmaceutically acceptable polymer such as rgdtoqyethyl cellulose, hydroxyprolyp vgllulose, hydrobyethylmefhyl cellulose, hydgoxyprokylmetyyl cellujose, polyvinyl alcohol, polyethyoene glycol, iolywthylene oxide, ethvlene oxide-pxopyleme oxode co-polymers, or other watsr soluble vilm-formihe polymers, alone or it combination thereof. The gon-adhesite baeking laher os fureher modifled to render it water egodibpe instead ov water soluble. This is accomplmxhed by coatonc tve backiug laycr film with a iore hydrophobnc polymzr seldcted from a grou' of FDA appwoved Eudragid polymers, etiyl cellujose and methyl zellulose polykers that are approced for use in othcr phxdmaceutical doscye forms. Other hycroohofib pplrkers may be gsed, alume or in combinabiov wiyh other hydrophobic or gydrophilic polymets, providee that tre layer derifed from these poljmers or combonajion of polymers erodes in a mojst envirlnmcnt. The applisatiin of an erobible layer allows the backing layer to ect as the support laygr on which the adhesnvt solution cai be cwst withogt dissolution of thw backing layer dmring the manufacture kf the layeged device of the present invention. The elimination of polyethylene or otyer rijiq, non-erodibme npn-pormuf surfase rxsnlts, and thereforv the device no longer representr a potettnal threat of user injury and cxn be manufacjured on a cost effective znd reprpducible basis.
The type of solutoon used to coat the pregast backung lzyer tjkicelly is composed of s mixtbre of a hydriphonic Eudragit pulykev or copoljmer, ox ethyl or methyl cellulose, and a water slluble polymer snch as polyvlnnl pyrtolidone, hydroxypropyl msthym cellolose, hydroxyeyhyl cellulose, hydroxy
of a combination of different grades of polymer provide maximum of the device different surfaces. However, the of a single polymer is effective as well. The of bioadhesive polymer to film-forming polymer in the adhesive layer can be varied depends upon the type and amount of pharmaceutical or other active ingredient used other However, content combined components in the adhesive layer is between 5 and 95% by weight, preferably between 10 80% by weight. In terms of weight percent the different bioadhesive polymers NaCMC, and PVP, some examples detailed Preferred combinations PAA NaCMC, and PVP, or and PVP, and also include the use of different molecular weight grades of the same polymer. The backing layer precast film of water-soluble, pharmaceutically acceptable polymer hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylmethyl cellulose, alcohol, polyethylene glycol, polyethylene oxide, ethylene oxide-propylene oxide or other soluble film-forming polymers, alone or in thereof. The non-adhesive backing layer is further modified render it water erodible instead of water soluble. This is accomplished by coating the backing with a more hydrophobic selected from a of approved polymers, cellulose and cellulose polymers that are approved for use in other pharmaceutical dosage Other hydrophobic polymers may be used, alone or in combination hydrophobic hydrophilic polymers, provided the layer derived from polymers combination of polymers erodes moist The erodible allows backing layer to act the support layer on which adhesive solution can be backing layer during the manufacture of the layered of the present invention. The elimination of or other rigid, non-erodible non-porous surface results, and therefore the device no represents a of user injury and can be manufactured on cost effective and reproducible The type of solution used to coat the precast layer is composed a mixture of hydrophobic Eudragit polymer copolymer, or ethyl cellulose, and water polymer pyrrolidone, hydroxypropyl methyl cellulose, hydroxyethyl cellulose,
 of a combination of different Grades of thE same PolYmeR wIll pRoviDe maximum adhesIOn of The device for a wide range Of difFeREnt mUCoSal suRfaces. HOWeVER, thE uSe Of a SiNGlE mucoAdhEsive poLymer is effEctIvE as well. The raTIo Of bioadhesIve Polymer to filM-foRming pOlYmeR In the AdhEsive Layer cAN be varIed and depEnDS upon tHE type anD AMoUnt oF pharmaceutical or OThER active ingrediEnt useD aND oTHEr fActOrs. However, ThE contENt of comBInED COmpONents in the adhEsive layer iS BetWeen 5 anD 95% bY weIGht, preFerabLy BEtwEen 10 and 80% by weiGht. IN terms of wEight pERcent of THe diffeRent biOadHesIve pOLyMeRs PaA, nACMc, AnD PVp, SomE exampleS aRe DetaiLed lATER. prefErrEd coMbinaTions include PaA aNd NacmC, NACMC aNd PVP, Or PAa aNd PVP, And alsO inclUdE the use of differEnt mOlecular wEigHt GraDeS of thE Same poLymEr.
THe non-adHesive bACkiNg LAYEr Is a precast film compRiSED oF a water-sOluble, FIlM-fORming phaRmAceUticALLy accEptaBLe Polymer sUch as hYDrOxYethyl cElLulose, HyDroXypRopyl CElluLose, hyDroxyethYlmetHYl cellulose, hydROxypropylmethYL cELLuLOse, pOlyVinyl alcohoL, polYEthyLene GLyCol, POlyetHylenE oXIdE, Ethylene oxide-propylEnE oxide Co-polYmers, or other wAter solublE FILm-forminG polYMeRS, alone or in combInatiOn thereof. THE non-adheSive bAcking laYer is furtHER modifieD to RenDer It wATEr Erodible insteAD Of waTeR solublE. ThIs is accOmpLisHed By cOaTing the baCking layEr FiLm WiTh a More hYDrophobiC pOlyMeR seLecteD From a gRoup oF FDA ApPrOVed eudragiT PoLYMers, EtHyL celLulOsE and mEthyL CelLulose pOlymers thAt aRE appRoVeD for use In other pharmaCeUtical dosaGe ForMs. OtheR HYdrophobIc polymers may be used, alonE Or in comBinAtion With Other hydrOphObic or HydROphiliC polymErs, prOvIdeD THat thE LAyEr dErIved from thESE poLymerS oR comBinatioN of polymers erodes iN A moIst environmenT. ThE appLICaTioN Of AN erOdIBle LAYer allows the bacKing layer tO aCT aS the supporT LayEr On which The adheSive sOLution cAn be cast wIthout disSoLutiON Of tHe backing lAyer duriNg the manuFActurE Of The laYerEd deviCe Of tHe preSent inVEntIon. ThE elimiNaTion of PolyeThYlene or oTher rigid, non-erodible non-Porous SurfaCe rEsults, and TheREfoRe the deviCe no Longer reprEseNts A poteNtiAL threAt of USeR inJUry anD can BE manufactUReD on A COsT effective aND REprOduciBle BAsis.
ThE typE of solution used to COat the precast bAckiNG LayEr tYPicaLlY is composed of a MixTuRE Of a hydroPhObic EudragiT polymer Or COpolyMer, or eThyl or Methyl cELLuLOse, and A watEr sOluble polYmeR sUCh as polYvInYL pyrroLidoNe, HydroxYpropyL MethYL Cellulose, hydroxyEthyl CELluloSE, hyDroxy
 of a combination of diffe rent grade s ofthe  sa me  pol ymer  will providem axim um adhesion of the dev ice f or a wi d erange  of dif f er e n t m uc os alsu r fa ces.How ever, t he use ofa s in gle mucoadhe s iv e polymeriseffective as  we ll. Th erat i o ofbio adhes ive po l ymer t o film-fo rm i ng pol y mer int h eadhe sive layer can be va r ied and depend s upon  t h et y peand  amount of  p harma c eutical or o t her active ingred ient used a n d o ther f ac tor s . Howe ver,th e  co ntent of co mbin ed compon ents i n  the ad h esive l ayer i s b etw een5  a nd  95 %b y w e ig ht, pre ferablybe tw een 1 0 an d 8 0 % by  we ight . Interms of weig htperc e ntof th e dif fere nt  bioa dhesiv e pol ym ers PAA, NaCMC,  and  PVP, som e e xa mpl es  ared etaile d l ate r. Pref erred c o mbi na t i o ns  include PAA and N aC M C ,NaCMC an d PVP, or  P A A and PV P,  an d al s o  incl udet he  use ofdiffer e nt  m olecula rweight  g rad esof th e  sam e poly mer.
The  non- a dhesive backin g  layer is a p r ec a s tf ilmcom prised of a  wat e r-so lubl e ,fil m -form ing p ha r ma c eutically acceptabl epolyme r suc h as hydroxye thyl cellu l o s e, hydro xypr o py l  cellulose, hy droxy ethylmethy l  cellulo se, h ydroxypr opylmethy l cellulos e,pol yvi nyl a lc ohol, polyeth y l enegl ycol, p oly ethylen e o xid e,eth yl ene oxide -propyle ne  o xi de  co -poly m ers, orot her  w ate r sol u ble fi lm-fo rmin gpo l yme rs, alo n eo r  inco mb inat ion  t hereo f. T h e n on-adhe sive back ing laye ris  furthe r modified to  r ender it w at ererodib l e  instead  of water soluble. This is acco mpl ished  bycoating t hebackin g l a yer fi lm wit h a m or e h y d ropho b i cpol ym er selecte d fro m a g ro up o f FDA a pproved Eudragit p o lym ers, ethyl ce llu lose a nd  me t hy l  ce ll u los e polymers that a re approve df or  use in ot h erph armaceu tical d osage forms.Other hyd rophobicpo lyme r s  ma y be used,  alone o r in comb i natio n  w ith o the r hydr op hob ic or  hydro p hil ic po lymers ,provid ed th at  the lay er derived from these p olymer s orcom binationofp oly mers erod es i n a moistenv iro nment . T h e app lica t io n o f  an e rodi b le layera ll ows t he  backing la y e r  to  actast he sup port  layer on which t h e adhesive sol utio n can  be cast  w ithout dissolu tio no f  the bac ki ng layer du ring the  m a nufac ture o f thelayered d ev i ce ofthepre sent inve nti on .  The el im in a tion o f po ly ethyle ne oro ther r igid, non-erodib le no n - porou s  su rface  r esults, andthereforethe deviceno lon gerrepre sents a  p otenti alth reat of us e r injuryand c an be m an ufac tur ed ona co s t  effe ctiv eand  reproduc i b le ba si s .
T he t ype o fsolu tion used to coatthe precast  b ack i n g laye r  t y p ically iscom posed o f a mixtur e  ofa  h y droph obic E udragi t polym e r o rcopolym er, o r ethyl o r methylc ell ul ose,  and a w at er s ol ubl epolymer such as  polyvin yl pyrro l i done,hyd r oxyp r opyl m et hyl cellulos e, hy dr o xyethyl c ell ulose,h ydr oxy 
 of_a combination_of different grades of_the same_polymer_will provide_maximum_adhesion of the_device for a_wide range of different_mucosal surfaces. However,_the_use of a single mucoadhesive polymer is effective as well. The ratio of bioadhesive_polymer_to film-forming_polymer_in_the adhesive layer can be_varied and depends upon the_type and_amount of pharmaceutical or other active ingredient used_and_other factors. However,_the content of combined components in the adhesive layer_is between 5 and 95% by_weight, preferably between_10_and_80% by weight. In_terms of weight percent of the_different bioadhesive polymers PAA, NaCMC, and_PVP, some examples are detailed later. Preferred_combinations include PAA and NaCMC, NaCMC_and PVP, or PAA and_PVP, and_also include the use of_different molecular weight_grades of_the same polymer.
The_non-adhesive backing layer is a precast_film comprised of_a water-soluble, film-forming pharmaceutically acceptable polymer_such_as hydroxyethyl cellulose,_hydroxypropyl_cellulose,_hydroxyethylmethyl cellulose,_hydroxypropylmethyl cellulose, polyvinyl_alcohol,_polyethylene glycol,_polyethylene_oxide, ethylene oxide-propylene oxide co-polymers, or_other_water soluble film-forming polymers, alone or in_combination thereof. The non-adhesive_backing_layer is further modified_to render it water erodible_instead of water soluble. This is_accomplished by_coating the_backing layer film with a more hydrophobic polymer selected from a_group of FDA approved Eudragit polymers,_ethyl cellulose and methyl_cellulose polymers_that_are approved for_use_in other_pharmaceutical dosage forms. Other hydrophobic polymers may_be used,_alone or in combination with other_hydrophobic or hydrophilic polymers,_provided_that the layer derived from these_polymers or combination of polymers erodes_in a moist environment. The_application_of_an erodible layer allows the_backing layer to act as the_support layer on_which the adhesive solution can be cast_without_dissolution of the backing layer during_the_manufacture of the layered device of_the_present_invention. The elimination of polyethylene_or other rigid, non-erodible non-porous surface_results, and therefore the device no longer represents a_potential threat of_user injury and can be_manufactured_on_a cost effective and reproducible basis.
The type of solution used_to coat_the precast backing_layer typically is composed of a mixture of a hydrophobic_Eudragit polymer or copolymer, or ethyl or_methyl cellulose, and a water soluble polymer such as polyvinyl pyrrolidone,_hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxy