AU769500B2 - Pharmaceutical carrier device suitable for delivery of pharmaceutical compounds to mucosal surfaces - Google Patents

Description

AUSTRALIA

Patents Act 1990 ViroTex Corporation

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Pharmaceutical carrier device suitable for delivery of pharmaceutical compounds to mucosal surfaces The following statement is a full description of this invention including the best method of performing it known to us:- S C

S.

oo 1 r -1A- PHARMACEUTICAL CARRIER DEVICE SUITABLE FOR DELIVERY OF PHARMACEUTICAL COMPOUNDS TO MUCOSAL SURFACES FIELD OF THE INVENTION The present invention relates generally to a water-erodable pharmaceutical carrier which adheres to mucosal surfaces for the localized delivery of pharmaceutical compounds and protection of the treatment site.

BACKGROUND OF THE INVENTION The localized treatment of body tissues, diseases, and wounds requires that the particular pharmaceutical component be maintained at the site of treatment for an effective period of time. Given the tendency of natural bodily fluids to rapidly wash away topically applied pharmaceutical components, the topical treatment of wet mucosal tissues has been 15 problematic. In the mouth, saliva, natural replacement.of the mucosal tissue, as well as, ieating, drinking, and speaking movements are some of the problems that have limited the :effectiveness and residence time of pharmaceutical carriers.

Bioadhesive carriers are known in the art and.include gels, pastes, tablets, and films.

These products, however, may lack one or several of the preferred characteristics:for an :i 20 efficient and commercially acceptable pharmaceutical delivery device. Some characteristics which are preferred by users of bioadhesive carriers include water-erodability; ease of handling and application to the treatment site; ease of comfort; minimal foreign body sensation; and unidirectional, specific release into the mucosal tissue. Other preferred characteristics for an effective and user-friendly product for the treatment of mucosal surfaces 25 include the use of pharmaceutically approved components or materials; instantaneous adhesion to mucosal surface upon application; increased residence time for the protection of the affected tissue or the delivery of the pharmaceutical component; and ease of removal of the delivery device from the affected tissue or natural erosion of the delivery device at the delivery site.

-I Bioadhesive gels which are used for application to mucosal tissues and especially the oral cavity are known in the art. For example, U.S. Patent No. 5,192,802 describes a bioadhesive teething gel made from a blend of sodium carboxymethyl cellulose and xanthan gum. The gel may also have potential use in the treatment of canker sores, fever blisters, and hemorrhoids. However, this type of pharmaceutical carrier has a very limited residence time, given that body fluids such as saliva quickly wash it away from the treatment site.

Bioadhesive gels are also described in U.S. Patent Nos. 5,314,915; 5,298,258; and 5,642,749.

The gels described in those patents use an aqueous or oily medium and different types of bioadhesive and gelling agents.

to Denture adhesive pastes are another type of bioadhesive product known in the art.

However, these preparations are used primarily for their adhesive properties, to adhere dentures to the gums, rather than for the protection of tissue or for the topical delivery of pharmaceuticals, although drugs such as local anesthetics may be used in the paste for the relief of sore gums. U.S. Patent Nos. 4,894,232 and 4,518,721 describe denture adhesive is5 pastes. The '721 Patent describes a combination of sodium carboxymethyl cellulose and polyethylene oxide in polyethylene glycol.

C" Pastes have also been used as film protectants and as drug delivery systems. One such example having film forming and adhesive properties is the product commercialized under the name Orabase®-B, which is a thick gel or paste for the relief of mouth sores. Ingredients S 20 include guar gum, sodium carboxymethyl cellulose, tragacanth gum, and pectin. Even though it does provide numbing to the area of application, the film forming behavior and bioadhesion do not last. Thus, this product has a limited residence time.

Bioadhesive tablets are described in U.S. Patent No. 4,915,948. The water-soluble bioadhesive material used in this device is a xanthan gum or a pectin combined with an 25 adhesion enhancing material such as a polyol. Although residence time is improved with the use of bioadhesive tablets, they are not user friendly, especially when used in the oral cavity, given the unpleasant feelings associated with their solidity, bulkiness, and slow erosion time.

S~ r, -3- Bioadhesive tablets are also described in U.S. Patent Nos. 4,226,848; 4,292,299; and 4,250,163, and are single layer or bilayer devices having an average thickness of 0.2 to mm. The bioadhesive tablets described in these patents utilize a non-adhesive component such as cellulose ether, a bioadhesive component such as polyacrylic acid, sodium carboxymethyl cellulose, or polyvinylpyrrolidone, and a binder for tableting purposes. The cellulose derivatives may or may not be water-erodable.

The use of bandages or bioadhesive laminated films, which are thinner and flexible and therefore have a decreased foreign body sensation, is described in U.S. Patent Nos.

3,996,934 and 4,286,592. These products are used to deliver drugs through the skin or mucous. The laminated films usually include an adhesive layer, a reservoir layer, and a backing layer. Bioadhesive devices designed to release drug through the skin at a given rate and over a period of time are usually not water soluble, and thus are not dissolved or washed away by bodily fluids.

In addition to film systems for the delivery of drug through the skin, film delivery 15 systems for use on mucosal surfaces are also known. These types of systems, which are water-insoluble and usually in the form of laminated, extruded or composite films, are described in U.S. Patent Nos. 4,517,173; 4,572,832; 4,713,243; 4,900,554; and 5,137,729.

The '173 Patent describes and claims a membrane-adhering film consisting of at least three layers, including a pharmaceutical layer, a poor water soluble layer, and an intermediate 20 layer. The pharmaceutical layer includes the drug and a cellulose derivative selected from hydroxypropyl cellulose, methyl cellulose, and hydroxypropyi'methyl cellulose. The poor water soluble layer is made by the combination of one or more cellulose derivatives with a poor water soluble fatty acid, and the intermediate layer is made of cellulose derivatives. The '832 Patent relates to a soft film for buccal delivery, made by the combined use of a water 25 soluble protein, a polyol, and a polyhydric alcohol such as cellulose and polysaccharides, and also teaches the use of coloring or flavoring agents. The '243 Patent describes a single or multi-layered bioadhesive thin film made from 40-95% water soluble hydroxypropyl cellulose, 5-60% water-insoluble ethylene oxide, 0-10% water-insoluble ethyl cellulose, I C, -4propyl cellulose, polyethylene, or polypropylene, and a medicament. The films are threelayered laminates and include a bioadhesive layer, a reservoir layer, and a non water-soluble outer protective layer. The '729 Patent teaches a soft adhesive film applicable to the oral mucosa containing a systemic drug and comprising a mixture of a vinyl acetate non watersoluble homopolymer, an acrylic acid polymer, and a cellulose derivative. Finally, the '554 Patent describes a device for use in the oral cavity having an adhesive layer including a mixture of an acrylic acid polymer, a water-insoluble cellulose derivative, and a pharmaceutical preparation, and a water-insoluble or sparingly soluble backing layer. The adhesive layer contains the pharmaceutical, and upon application to the mucosal surface, to delivers the drug. The '554 Patent also states that "it is impossible to achieve an adhesive device for application to body tissue without all three components, that is, acrylic acid polymer, water insoluble cellulose derivative and a water insoluble or sparingly soluble backing layer." JP 56-100714 describes a preparation which comprises a coating layer and an active S* s15 ingredient layer. The coating layer adheres to the mucosal membrane and is comprised of a cellulose ether or an acrylic acid polymer or salt. The active ingredient layer comprises an ointment base comprised of water-insoluble substances such as fats and oils, waxes, hydrocarbons, higher fatty acids, higher alcohols, polyhydric alcohols or glycerol esters. A surfactant and active ingredient are also present in the active ingredientiayer. Thus, the 20 active ingredient is mixed with an essentially non-water erodable substance. The previous examples of thin films to be applied in the oral cavity by adhesion onto the mucosal tissues all utilize polymers which are water-insoluble by nature or which are-made water-insoluble by crosslinking, and claim a long residence time. Therefore, unfortunately, the above examples of thin films do not provide a water erodable device with good adhesive properties.

25 Therefore, upon release of the desired amount of drug, the thin films of water insoluble polymers must be peeled off the site of application. Such peeling often removes tissue from the mucosal tissue and is painful to the patient. What is needed in the art is a water-erodable pharmaceutical delivery device which provides good adhesion and localised delivery of a pharmaceutical with minimal discomfort for the patient.

The FR-A-2 582 942 describes adhesive medical tapes for application to the oral mucosa. The tapes comprise a support layer containing a polymer soluble in the intestine and a medicament-containing layer comprising a water-soluble polymer.

European Patent Application EP-A-0 262 422 teaches a sustained release dosage device consisting of a drug reservoir, an adhesive layer, and a backing layer. The backing layer does not dissolve in saliva.

European Patent Application EP-A-0 159 604 teaches a sustained release preparation for use on mucosal membranes. Layers are prepared from a mixture of a first and second polymer component, the first comprising polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, alginic acid or a salt thereof, and an alternating copolymer of maleic anhydride and methyl vinyl ether, and the second comprising polyacrylic acid or a salt thereof.

SUMMARY OF THE INVENTION The present invention relates to a novel water-erodible pharmaceutical carrier device for application to mucosal surfaces to provide protection of and localised delivery of a pharmaceutical to the site of application, surrounding tissues, and other bodily fluids such as blood or lymph, having an effective residence time, with minimal discomfort and ease of use.

In one embodiment, the pharmaceutical delivery device includes a layered flexible film having a first water-erodible adhesive layer to be placed in contact with a mucosal surface, a second water-erodible non-adhesive backing layer, and optionally a pharmaceutical incorporated with said first layer, said second layer, or both layers, wherein said first water-erodible adhesive layer comprises a film-forming polymer and a bioadhesive polymer, and wherein said second water-erodible non-adhesive layer comprises a filmforming polymer.

In another embodiment, the pharmaceutical delivery device further comprises a third layer between the first water-erodible adhesive layer and the second water-erodible non-adhesive backing layer. The third layer is a water-erodible adhesive layer which has a surface area sufficient to encompass said first adhesive layer and contact the mucosal surface. In this manner, localised delivery of a pharmaceutical may be accomplished in a unidirectional manner toward the mucosal layer.

The adhesive layer(s) comprise(s) a film-forming polymer such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl methyl cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, ethylene oxide-propylene oxide co-polymers, collagen and derivatives, gelatin, albumin, polyaminoacids and derivatives, polyphosphazenes, polysaccharides and derivatives, chitin, or chitosan, alone or in combination and a bioadhesive polymer such as polyacrylic acid, polyvinyl pyrrolidone, or sodium carboxymethyl cellulose, alone or in combination.

The non-adhesive backing layer(s) comprise(s) hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, or ethylene oxide-propylene oxide co-polymers alone or in combination.

In another embodiment of the invention, one or more of the layers of the device further comprise a component which acts to adjust the kinetics of the erodibility and provide a convenient manner of altering the release of the 20 pharmaceutical and the lifespan of the device. A component which acts to adjust the kinetics of the erodibility is a water-based emulsion of a S.polylactide, polyglycolide, lactide-glycolide co-polymers, poly-e-caprolactone and derivatives, polyorthoesters and derivatives, polyanhydrides and derivatives, ethyl cellulose, vinyl acetate, cellulose acetate, and polyisobutylene, alone or in combination. Another component which acts to adjust the kinetics of the erodibility is alkyl-glycol, propylene glycol, polyethyleneglycol, oleate, sebacate, stearate or esters of glycerol, or .:..phthalate, alone or in combination.

**In another embodiment of the invention, the number of layers of the device further may be varied to adjust the kinetics of the erodibility and provide a convenient manner of altering the release of the pharmaceutical and the lifespan of the device.

In a preferred embodiment, the second water-erodible non-adhesive backing layer comprises two or more layers with different erodibility kinetics.

I In yet another embodiment, the present invention provides a pharmaceutical carrier device comprising a layered flexible film having a first water-erodible adhesive layer to be placed in contact with a mucosal surface, a second water-erodible non-adhesive backing layer, and optionally a pharmaceutical incorporated with said first layer, said second layer, or both layers, wherein said first water-erodible adhesive layer comprises a film-forming polymer and a bioadhesive polymer, and is free of a plasticizer, and wherein said second water-erodible non-adhesive backing layer comprises hydroxyethyl cellulose.

In a further embodiment, the present invention provides a layered flexible film disk which adheres to mucosal surfaces for the localised delivery of pharmaceutical, comprising a first water-erodible adhesive layer and a second water-erodible non-adhesive backing layer, wherein said pharmaceutical or combination of pharmaceuticals is incorporated with said first water-erodible adhesive layer, or said second water-erodible non-adhesive backing layer, or both said first adhesive watererodible layer and said second non-adhesive backing layer, and wherein said first water-erodible adhesive layer comprises a film-forming polymer and a bioadhesive polymer, and is free of a plasticizer wherein said second water-erodible non-adhesive backing layer comprises hydroxyethyl cellulose, said layered flexible film having a 20 total thickness of from 0.1 mm to 1 mm.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a S context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or S•step, or group of elements, integers or steps, but not the exclusion of any other element, i r g ei o integer or step, or group of elements, integers or steps.

*o• 6b BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a three layered film disk wherein layers 2 and 3 are bioadhesive layers and layer 1 is a backing layer.

Figure 2 is a three layered film disk wherein two of the layers are bioadhesive layers and the other layer is a backing layer. The bioadhesive layer, layer 3, which will adhere to the mucosal tissue is of smaller surface area and encompassed by the second bioadhesive layer, layer 2, to provide unidirectional delivery. Layer 1 is a backing layer.

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "water-erodible" means that the component, device, layer, etc.

erodes in water-based media such as saliva, over time. Such erosion in water may be due to factors such as dissolution, dispersion, friction, gravity, etc.

*o* As used herein, the term "kinetics of erodability" or "erosion kinetics" refers to the timing of the release of pharmaceutical from the carrier device (release profile), as well as, the timing of the erosion of the device itself over time (lifespan or residence time of the device). As described herein, kinetics of erodability are based on factors such as type and amount of components in the device, thickness and number of layers in the device, and additives or excipients in the device. In a case in which all the components of the device are very water soluble, the kinetics of erodability will closely parallel the solubility kinetics.

In the present invention, a novel water-erodable pharmaceutical device which adheres to mucosal surfaces is provided. The present invention finds particular use in the localized to treatment of body tissues, diseases, or wounds which may have moist surfaces and which are susceptible to bodily fluids, such as the mouth, the vagina, or other types of mucosal surfaces.

The device carries a pharmaceutical, and upon application and adherence to the mucosal surface, offers a layer of protection and delivers the pharmaceutical to the treatment site, the surrounding tissues, and other bodily fluids. The device provides an appropriate residence is time for effective drug delivery at the treatment site, given the control of erosion in aqueous solution or bodily fluids such as saliva, and the slow, natural erosion of the film concomitant or subsequent to the delivery. In one embodiment, the pharmaceutical delivery device comprises a layered film disk having an adhesive layer and a backing layer, both watererodable, having the pharmaceutical in eitheri.or both layers.

20 Unlike bioadhesive gels and pastes known in the art, which have a very limited residence time, given the tendency of bodily fluids such as saliva to wash away the gel from the treatment site, the present invention offers an increased residence time because of its filmy consistency and components. A typical residence time for an aqueous gel or paste, such as Orajel®, Orabase®, or Kanka® is a few minutes. This short residence time is a 25 consequence of a limited or poor adhesion. In a typical aqueous gel, the mucoadhesive components are either in solution, suspension, or swollen. Once applied to the mucosal surface, however, the water based gel does not instantaneously penetrate the lipophilic mucosal surface. The composition and water affinity of these gels results in a tendency to quickly mix with the saliva, rapidly pulling away the different components of the gel, and limiting the residence time. The same tendency is expected with pastes, the increase in viscosity only slightly delaying the timing. The present invention, by its solid form and its instantaneous adhesion to the mucosal surface, allows a lasting contact, a consequence of the entanglement of polymer chains and glycoproteins of the mucosal tissue which assures adhesion. Erosion kinetics in the saliva and other aqueous media are influenced by the physical state of the device. While a gel or solution will readily mix with saliva and/or other bodily fluids, a solid form of the same or similar composition, such as the film of the present invention, dissolves erodes more slowly.

to Also, unlike the bioadhesive tablets which are known in the art, the pharmaceutical device of the present invention minimizes the discomfort associated with application of a foreign substance for a period of time sufficient to provide effective drug delivery to the treatment site. Often, users of the bioadhesive tablets of the prior art experience unpleasant sensations due to their solidity, bulkiness, and slow dissolution time if erodable, especially 15 when used in the oral cavity. Moreover, the typical thickness of bioadhesive tablets, which may or may not be water soluble, is a couple of millimeters, and because of their thickness, the preferred site of application is on the upper gingival area. This site is usually unsatisfactory for local delivery as the type of compounds to be delivered, their bioavailability, and pharmokinetics is limited. In contrast to.tablets, the device of the present 20 invention offers the advantages of an effective residence time with minimal discomfort and ease of use, and is an appropriate vehicle for the local, as well as systemic, delivery of pharmaceutical, given its thinner, flexible form. Finally, unlike the film systems known in the art-which are used to deliver pharmaceutical through the skin or mucous, the device of the present invention is made of 25 water-erodable components and thus is bioerodable. The use of water-erodable components allows the device to erode over a period of time, with natural bodily fluids slowly dissolving or eroding away the carrier, while the pharmaceutical remains at the application site. Unlike bandages and other non-water-erodable film systems, the user of the present invention does not have to remove the device following treatment. Nor does the user experience the sensation of the presence of a foreign object at the mucosal surface or within the body cavity, given that upon application, water absorption softens the device, and over time, the device slowly dissolves or erodes away.

The residence time of the device of the present invention depends on the erosion rate of the water-erodable polymers used in the formulation and their respective concentrations.

The erosion rate may be adjusted, for example, by mixing together components with different solubility characteristics or chemically different polymers, such as hydroxyethyl cellulose and hydroxypropyl cellulose; by using different molecular weight grades of the same polymer, to such as mixing low and medium molecular weight hydroxyethyl cellulose; by using excipients or plasticizers of various lipophilic values or water solubility characteristics (including essentially insoluble components); by using crosslinking agents such as glyoxal with polymers such as hydroxyethyl cellulose for partial crosslinking; or by post-treatment irradiation or curing, which may alter the physical state of the film, including its crystallinity is or phase transition, once obtained. These strategies might be employed alone or in combination in order to modify the erosion kinetics of the device.

Upon application, the pharmaceutical delivery device adheres to the mucosal surface and is held in place. Water absorption softens the device, thereby diminishing the foreign body sensation. As the device rests on the mnicosa surface, delivery of the drug occurs.

20 Residence times may be adjusted over a wide range depending upon the desired timing of the delivery of the chosen pharmaceutical and the desired lifespan of the-carrier. Generally, however, the residence time is modulated between about a few seconds to about a few days.

Preferably, the residence time for most pharmaceuticals is adjusted from about 30 minutes to about 24 hours. More preferably, the residence time is adjusted from about 1 hour to about 8 25 hours. In addition to providing drug delivery, once the device adheres to the mucosal surface, it also provides protection to the treatment site, acting as an erodable bandage.

In one embodiment, the present invention comprises a film disk having an adhesive layer and a non-adhesive backing layer which can be comprised of components having a similar or different hydrophilicity. The pharmaceutical component may be included in either layer, although preferably, it is included in the adhesive layer, which is closest to the treatment site and which will have a slower erosion time, given that the backing layer protects the interior, adhesive layer and will typically erode first.

The adhesive layer may comprise at least one film-forming water-erodable polymer (the "film-forming polymer") and at least one pharmacologically acceptable polymer known for its bioadhesive capabilities (the "bioadhesive polymer"). The film forming polymer may comprise hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl methyl cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, to ethylene oxide-propylene oxide co-polymers, collagen and derivatives, gelatin, albumin, polyaminoacids and derivatives, polyphosphazenes, polysaccharides and derivatives, chitin and chitosan, alone or in combination. Preferably, the film-forming polymer comprises hydroxyethyl cellulose. Preferably, in the case of hydroxyethyl cellulose, the average molecular weight (Mw estimated from intrinsic viscosity measurements) is in the range 10 2 to 106 and more preferably in the range 103 to 105, while in the case of hydroxypropyl cellulose, the average molecular weight (Mw obtained from size exclusion chromatography measurements) is in the range 50 x 103 to 1.5 x 106, and more preferably between 80 x 103 to 5 x 105.

The bioadhesive polymer of the adhesive layer may comprise polyacrylic acid (PAA), 20 which may or may not be partially crosslinked, sodium carboxymethyl cellulose (NaCMC), and polyvinylpyrrolidone (PVP), or combinations thereof. These bioadhesive polymers are o preferred because they have gobd and instantaneous mucoadhesive properties in a dry, film state. In the case of sodium carboxymethyl cellulose, typical average molecular weights comprise 50,000 to 700,000, and preferably 60,000 to 500,000, with a degree of substitution of 0.7. The substitution range varies between 0.5 and 1.5, and preferably between 0.6 and 0.9. The polyvinyl pyrrolidone can be characterized according to its average molecular weight and comprises between 5,000 and 150,000, preferably between 10,000 and 100,000.

I -11 The simultaneous use of PAA with some grades of PVP may result in the precipitation of one or both components. This precipitation may not be ideal to obtain a homogenous layer and may slightly alter the overall adhesive properties of the device.

While not wishing to bound to a particular theory, it is believed that the adhesion properties of the present invention are the result of the entanglement of polymer chains and interactions with glycoproteins of the mucosal surface. The chemical nature of the bioadhesive polymers, including chain and side groups and crosslinking agents, generates interactions between the mucosal constituents and the polymer or polymers, such as physical entanglement, Van der Waals interactions, and hydrogen bonding. Given that the 0o composition of mucosal tissues differs from one individual to another and changes naturally over time, the use of a combination of bioadhesive polymers or the use of a combination of different grades of the same polymer is preferred. The use of a combination of at least two bioadhesive polymers maximizes the adhesion capabilities of the device, although use of a *single bioadhesive polymer is effective as well.

Is The ratio of the bioadhesive polymer to the film-f6rming polymer in the adhesive layer may vary, depending on the type of pharmaceutical and the amount of pharmaceutical to be used. However, the content of combined components in the adhesive layer is usually 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 provided below and using the examples one skilled in the art will be able to readily adjust the percentages to obtain a pharmaceutical device having desired characteristics for a given application. Preferred combinations include PAA and NaCMC, NaCMC and PVP, or PAA *i and PVP, and also include the use of different grades of the same polymer.

The non adhesive backing layer may comprise a water-erodable, film-forming pharmaceutically acceptable polymer such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyethylmethyl cellulose, polyvinylalcohol, polyethylene glycol, polyethylene oxide, ethylene oxide-propylene oxide co-polymers, collagen and derivatives, gelatin, albumin, polyaminoacids and derivatives, I -12polyphosphazenes, polysaccharides and derivatives, chitin and chitosan, alone or in combination. The backing layer component may or may not be crosslinked depending on the desired erosion kinetics. In one embodiment, the preferred backing layer component comprises hydroxyethyl cellulose or hydroxypropyl cellulose, and more preferably comprises hydroxyethyl cellulose. Preferably, in the case of hydroxyethyl cellulose, the average molecular weight (Mw estimated from intrinsic viscosity measurements) is in the range 102 to 106, and more preferably in the range 103 to 105, while in the case of hydroxypropyl cellulose, the average molecular weight (Mw obtained from size exclusion chromatography measurements) is in the range of 50 x 103 to 1.5 x 106 and more preferably from 80 x 103 to io 5 x 10 5 As described above, the erosion kinetics of one or more of the layers (adhesive layer, ibacking layer, or both) may be altered in many different ways in order to modify the S* residence time and the release profile of a drug. One way is by crosslinking or plasticizing the film-forming polymer. Crosslinking agents known in theart are appropriate for use in the invention and may include glyoxal, propylene glycol, glycerol,-diiydroxy-polyethylene glycol of different sizes, butylene glycol, and combinations thereof. The amount of crosslinking agent used may vary, depending on the particular polymers andcrosslinking agent but usually should not exceed 5% molar equivalent of the polymeric material, and preferably comprises 0 to 3% molar equivalent of the polymeric material. Another way of altering the residence time and release profile is by employing. a component in one or more of the layers which acts to adjust the kinetics of the erodability of the layer. While these components will vary widely depending upon the particular pharmaceutical delivery device employed, preferred components include water-based emulsions of polylactide, polyglycolide, lactide-glycolide copolymers, poly-e-caprolactone and derivatives, polyorthoesters and derivatives, polyanhydrides and derivatives, ethyl cellulose, vinyl acetate, cellulose acetate, silicone, polyisobutylene and derivatives, alone or in combination.

13- Emulsifiers typically used in the water-based emulsions described above are, preferably, either obtained in situ if selected from the linoleic, palmitic, myristoleic, lauric, stearic, cetoleic or oleic acids and sodium or potassium hydroxide, or selected from the laurate, palmitate, stearate, or oleate esters of sorbitol and sorbitol anhydrides, s polyoxyethylene derivatives including monooleate, monostearate, monopalmitate, monolaurate, fatty alcohols, alkyl phenols, alyl ethers, alkyl aryl ethers, sorbitan monostearate, sorbitan monooleate and sorbitan monopalmitate.

Furthermore, in the case of the water-insoluble polymeric materials such as the polyesteraliphatic family (co-polymers of lactide-glycolide, caprolactone, etc.) the average to molecular weight (Mw) is in the range 102 to 10 5 and, more preferably, 103 to 104, while in the case of the cellulosic family (ethyl cellulose, cellulose acetate, etc.), the average molecular weight (Mw estimated from intrinsic viscosity measurements) is in the range 102 S*.i to 106 and more preferably in the range 10 3 to 105.

Yet another manner of modifying the erosion kinetics of any layer, is by employing excipients which plasticize the film concomitantly. Suitable excipients-or plasticizers modifying the erosion behavior of the layer(s) may include alkyl-glycol such as propylene glycol, polyethyleneglycols, oleate, sebacate, stearate or esters of glycerol, phthalate and others.

It is also possible to modify the erosion kinetics of the device of the instant inventionby adjusting the thickness and number of layers. Typically, the thicker the layers, the slower the release of pharmaceutical and the longer the release profile. Correspondingly, the more layers there are, the slower the release of pharmaceutical and the longer the release profile. In a preferred embodiment, the backing layer comprises two or more layers with different erosion kinetics.

Moreover, combinations of different polymers or similar polymers with definite molecular weight characteristics may be used in order to achieve preferred film forming capabilities, mechanical properties, and kinetics of dissolution in any layer. Some I" -14combinations for use in the invention are provided in the examples below and may include of hydroxyethyl cellulose and '4 of hydroxypropyl cellulose; 4/5 of low molecular weight hydroxyethyl cellulose and 1/5 of medium molecular weight hydroxyethyl-cellulose; and 8/9 of low molecular weight hydroxyethyl cellulose and 1/9 of high molecular weight hydroxyethyl cellulose. As mentioned previously, combinations of water-erodable polymers may be employed in order to modify the erosion kinetics of the device. A particularly preferred combination includes '2 hydroxyethyl cellulose, 1/6 hydroxypropylcellulose, and 2/6 of a pseudolatex, i.e. emulsion of polymer, of lactide-glycolide copolymer.

The pharmaceutical component of the present invention may comprise a single o0 pharmaceutical or a combination of pharmaceuticals, which may be incorporated in the adhesive layer, the backing layer, or both. Pharmaceuticals which may be used, either alone or in combination, include anti-inflammatory analgesic agents, steroidal anti-inflammatory .agents, antihistamines, local anesthetics, bactericides and disinfectants, vasoconstrictors, hemostatics, chemotherapeutic drugs, antibiotics, keratolytics, cauterizing agents, antiviral 15 drugs, antirheumatics, antihypertensives, bronchodilators, anticholinergics, antimenimic compounds, hormones and macromolecules, peptides, proteins and vaccines.

Examples of anti-inflammatory analgesic agents include acetaminophen, methyl salicylate, monoglycol salicylate, aspirin, mefenamic acid, flufenamic acid, indomethacin, diclofenac, alclofenac, diclofenac sodium, ibuprofen, ketoprofen, naproxen, pranioproferi, 20 fenoprofen, sulindac, fenclofenac, clidanac, flurbiprofen, fentiazac, bufexamac, piroxicam, phenylbutazone, oxyphenbutazone, clofezone, pentazocine, mepirizole, tiaramide hydrochloride, etc. Examples of steroidal anti-inflammatory agents include hydrocortisone, predonisolone, dexamethasone, triamcinolone acetonide, fluocinolone acetonide, hydrocortisone acetate, predonisolone acetate, methylpredonisolone, dexamethasone acetate, betamethasone, betamethasone valerate, flumetasone, fluorometholone, beclomethasone diproprionate, fluocinonide, etc.

Examples of antihistamines include diphenhydramine hydrochloride, diphenhydramine salicylate, diphenhydramine, chlorpheniramine hydrochloride, chlorpheniramine maleate isothipendyl hydrochloride, tripelennamine hydrochloride, promethazine hydrochloride, methdilazine hydrochloride, etc. Examples of local anesthetics include dibucaine hydrochloride, dibucaine, lidocaine hydrochloride, lidocaine, benzocaine, p-buthylaminobenzoic acid 2-(die-ethylamino) ethyl ester hydrochloride, procaine s hydrochloride, tetracaine, tetracaine hydrochloride, chloroprocaine hydrochloride, oxyprocaine hydrochloride, mepivacaine, cocaine hydrochloride, piperocaine hydrochloride, dyclonine, dyclonine hydrochloride, etc.

Examples of bactericides and disinfectants include thimerosal, phenol, thymol, benzalkonium chloride, benzethonium chloride, chlorhexidine, povidone iode, to cetylpyridinium chloride, eugenol, trimethylammonium bromide, etc. Examples of vasoconstrictors include naphazoline nitrate,.tetrahydrozoline hydrochloride, oxymetazoline hydrochloride, phenylephrine hydrochloride, tramazoline hydrochloride, etc. Examples of hemostatics include thrombin, phytonadione, protamine sulfate, aminocaproic acid, tranexamic acid, carbazochrome, carbaxochrome sodium sulfanate, rutin, hesperidin, etc.

Examples of chemotherapeutic drugs include sulfamine, sulfathiazole, sulfadiazine, homosulfamine, sulfisoxazole, sulfisomidine, sulfamethizole, nitrofurazone, etc. Examples-of antibiotics include penicillin, meticillin, oxacillin, cefalotin,.cefalordin, erythromcycin, lincomycin, tetracycline, chlortetracycline, oxytetracycline, metacycline, chloramphenicol, kanamycin, streptomycin, gentamicin, bacitracin; cycloserine, etc.

20 Examples of keratolytics include salicylic acid, podophyllum resin, podolifox, and.

cantharidin. Examples of cauterizing agents include the chloroacetic:acids and silver nitrate.

Examples of antiviral drugs include protease inhibitors, thymadine kinase inhibitors, sugar or glycoprotein synthesis inhibitors, structural protein synthesis inhibitors, attachment and adsorption inhibitors, and nucleoside analogues such as acyclovir, penciclovir, valacyclovir, and ganciclovir.

Examples of proteins, peptides, vaccines, genes and the like include heparin, insulin, LHRH, TRH, interferons, oligonuclides, calcitonin, and octreotide.

-16- The amount of active pharmaceutical to be used depends on the desired treatment strength and the composition of the layers, although preferably, the pharmaceutical component comprises from about 0.001 to about 99, more preferably from about 0.003 to about 30, and most preferably from about 0.005 to about 20% by weight of the device.

Plasticizers, flavoring and coloring agents, and preservatives may also be included in the pharmaceutical delivery device of the present invention in the adhesive layer, the backing layer, or both. The amount may vary depending on the drug or other components but typically these components comprise no more than 50, preferably no more than 30, most preferably no more than 15% by total weight of the device.

to A permeation enhancer may be added to the device to improve absorption of the drug.

Typically, such a permeation enhancer is added to the layer in which the pharmaceutical is to be contained. Suitable permeation enhancers include natural or synthetic bile salts such as sodium fusidate; glycocholate or deoxycholate; fatty acids and derivatives such as sodium laurate, oleic acid, oleyl alcohol, monoolein, and palmitoylcarnitine; chelators such as 15s disodium EDTA, sodium citrate and sodium laurylsulfate, azone, sodium cholate, sodium methoxysalicylate, sorbitan laurate, glyceryl monolaurate, octoxynonyl-9, laureth-9, polysorbates, etc.

The thickness of the device may vary, depending on the thickness of each of the layers and the number of layers. As stated above, both the thickness and amount of layers may be 20 adjusted in order to vary the erosion kinetics. Preferably, if the device has only two layers, Sthe thickness ranges from 0.05 mm to 1 mm, and more.preferably from 0.1 to 0.5 mm. The S. thickness of each layer may vary from 10 to 90% of the overall thickness of the layered device, and preferably varies from 30 to 60%. Thus, the preferred thickness of each layer may vary from 0.01 mm to 0.9 mm, and more preferably from 0.03 to 0.6 mm; While the device of the invention only requires two layers, an adhesive layer and a backing layer, it is often preferable to have additional layers. One instance in which this might be advantageous is when specific unidirectional flow of a pharmaceutical is required toward a mucosal layer. The layered device described above provides some directional -17release, release will mainly be toward the mucosa and not, for instance, into the oral or vaginal cavity. However, due to the swelling characteristics of the thin film, a small amount of pharmaceutical may also be released through the sides of the device and the backing layer if all the layers are of the approximately the same surface area and are essentially on top of s one another. While a preferential, but not specific, release is acceptable, and even desirable, for many pharmaceuticals, other pharmaceuticals may require unidirectional, specific release into the mucosal tissue.

An example of when unidirectional release may be desirable is when the pharmaceutical to be delivered has a specific therapeutic window or has undesirable side o1 effects if absorbed in the gastrointestinal tract. Furthermore, some pharmaceuticals are enzymatically degraded. Therefore, a bioerodible mucoadhesive system allowing a transmucosal unidirectional delivery and protecting the drug being delivered from enzymes present, for instance, in the oral or vaginal cavities would have advantages.

In such instances when unidirectional release is desired, an additional layer may be 15 placed between the first adhesive layer and the second backing layer. The third layer is a water-erodable adhesive layer which has a surface area sufficient to encompass said first adhesive layer and contact the mucosal surface. The third layer may be comprised of any of the components described above for the first adhesive layer and thus may be the same or different than the first adhesive layer. Figure 2 illustrates a disk having a-third layer which 20 encompasses the first adhesive layer.

If a bioadhesive layer is to be of a smaller surface area than the other layers then it is usually between about 5 and about 50, preferably between about 10 and about 30% smaller than the other layers.

In the aforementioned manner, localized delivery of a pharmaceutical may be accomplished in a unidirectional manner. For instance, if pharmaceutical is present in the first adhesive layer then it is prevented from being released through the sides and back of the device. If pharmaceutical is present in the backing layer, then it is prevented from entering -18the mucosal layer to which the device is adhered. Likewise, if a pharmaceutical is present in the first adhesive layer and the backing layer, they are prevented from mixing.

The pharmaceutical delivery device of the present invention may be prepared by numerous methods known in the art. In one embodiment, the components are dissolved in an aqueous medium or a combination of water and lower alkanols to prepare a solution, a gel, or a suspension that can be used for coating. Solvents for use in the present invention may comprise water, methanol, ethanol, or low alkyl alcohols such as isopropyl alcohol, or acetone. The final solvent content or residual solvent content in the film may be the result of either or both layers. The solvent may also be used as a plasticizer or an erosion rateto modifying agent.

Each solution is then coated onto a substrate. Eventually, one of the components might be in suspension. Each solution is casted and processed into a thin film by techniques known in the art, such as by film dipping, film coating, film casting, spin coating, or spray drying using the appropriate substrate. The thin film is then allowed to dry. If desired, the i Is drying step can be accomplished in any type of oven in-order to facilitate the process.

SHowever, as one skilled in the art will appreciate, the solvent residual, which may effect the erosion kinetics, depends on the drying procedure. The film layers may be filmed independently and then laminated together or may be -filmed one on the top of the other.

The film obtained after the two layers have been laminated together or coatedontop 20 of each other may be cut, if desired, into any type of shape whichis suitable for application to the mucosal tissue. Suitable shapes may include disks, ellipses, squares, rectangles, .:.parallepipedes, as well as, shredded, meshed, or porous films depending upon- the purpose and location where the device is to be employed. Likewise, the surface area of the device of the present invention will necessarily vary depending on many factors with the major factor being where the device is to be employed. Typically, the surface area may be from about 0.1 to about 30, preferably from 0.5 to about 20 square centimeters.

Methods for treating mucosal surfaces, surrounding tissues, and bodily fluids for localized and systemic drug delivery are also provided. In one embodiment, the method -19comprises applying an adherent film of the invention to the treatment site in order to provide protection to the treatment site and drug delivery. The adherent film may comprise any of the layered devices provided herein. In a preferred embodiment, the method comprises application of a layered pharmaceutical carrier device having a first adhesive layer and a second non-adhesive backing layer as described above, each layer having a thickness of from 0.01 mm to 0.9 mm. The pharmaceutical or combination of pharmaceuticals may be present in the adhesive layer, the non-adhesive backing layer, or both layers.

While the pharmaceutical carrier described in this application readily adheres to mucosal tissues, which are wet tissues by nature, it can also be used on other surfaces such as io skin or wounds. The water-soluble filmof the present invention will adhere to the skin if prior to application the skin is wet with an aqueous-based fluid such as water, saliva, or perspiration. The film will typically adhere to the skin until it erodes due contact with water by, for example, showering, bathing or washing, The film may also be readily removed by peeling without significant damage to tissue.

Is While it is in contact with the skin, the film may act as a washable, erodable bandage to protect the area where it has been applied. It is also possible to employ the film as a transdermal drug delivery system to facilitate the healing process and keep the wound or bum free of germs and debris. A significant advantage of the instant invention over conventional alternatives is that not only is the film washable, but also, perspiration helps the adhesion of.

000•0 20 the device instead of preventing or reducing it as with conventional transdermal patches.

The pharmaceutical carrier of the-present invention can also be used as a-wound dressing. By offering a physical, compatible, oxygen and moisture permeable, flexible barrier which can be washed away, the film can not only protect awound but also deliver a pharmaceutical in order topromote healing, asepty, scarification, to ease the pain or to improve globally the condition of the sufferer. Some of the examples given below are well suited for an application to the skin or a wound. As one skilled in the art will appreciate, the formulation might require incorporating a specific hydrophilic hygroscopic excipient which would help in maintaining good adhesion on dry skin over an extended period of time.

Another advantage of the present invention when utilized in this manner is that if one does not wish that the film be noticeable on the skin, then no dyes or colored substances need be used. If, on the other hand, one desires that the film be noticeable, a dye or colored substance may be employed.

EXAMPLE 1 A 100 ml solution for the non-adhesive backing layer was made using 87.98% by weight-water USP, 0.02% by weight FD&C red 40 dye, and 12% by weight hydroxyethyl cellulose (Mw 9 x 104). Using a Werner Mathis Labcoater, the substrate (Mylar 1000D or to other polyester films such as 3M ScotchPak 1022) was set. 90 ml of the backing layer solution was set in front of a knife over roll with an opening of 1.5 mm. The solution was then casted on a glass substrate and film dried for 8-9 min. at 1300 C. Following the drying step, a 0.14 mm thick reddish film was the result.

Using this procedure, the film may be easily peeled off the substrate after drying, or 15 may be left on the substrate and rolled, to be laminated later, or for use as a substrate.for the adhesive layer.

EXAMPLE 2.

A 100 ml solution for the non-adhesive backing layer was made using94.98% by 20 weight water USP, 0.02% by weight FD&C red 40 dye, and 5% by weight hydroxypropyl cellulose. The procedure of example 1 was used, resulting in a 0.16 mm thick film.

EXAMPLE 3 A 100 ml solution for the non-adhesive backing layer was made using 84.98%-by weight water USP, 0.02% by weight FD&C red 40 dye, 12% by weight hydroxyethyl cellulose, and 3% by weight hydroxypropyl cellulose. Here, the overall polymeric material was at a 15% concentration in solution. The mixture of two different types of polymeric materials modified the overall mechanical properties and erosion kinetics characteristics of -21the backing film. The solution was then casted on a polyester substrate and dried overnight at 0 C. The opening of the knife was set at 3 mm, resulting in a 0.3 mm thick film.

EXAMPLE 4 s A 100 ml solution for the non-adhesive backing layer was made using 87.98% by weight water USP, 0.02% by weight FD&C red 40 dye, 10% by weight hydroxyethyl cellulose (Mw 9 x 10 4 and 2% by weight hydroxyethyl cellulose (Mw 7 x 10 5 Here, the mixture of two different types of hydroxyethyl cellulose modified the mechanical properties and erosion kinetics of the backing film. The solution was then cast on a polyester substrate to and dried for 12 min. at 1350 C. The opening of the knife was set at 3 mm, resulting in a 0.27 mm thick film.

EXAMPLE A 100 ml solution for the non-adhesive backing layer was made using 87.98% by weight water USP, 0.02% by weight FD&C red 40 dye, 11.75% by weight hydroxyethyl Scellulose (Mw 9 x 104), and 0.25% by weight hydroxyethyl cellulose (Mw 1.3 x 106). The procedure of Example 1 was used, resulting in a 0.14 mm thick film.

Here, the mixture of two different grades of hydroxyethyl cellulose modified the mechanical properties and erosion kinetics of the backing film. The ratio may be used to 20 adjust the erosion pattern and residence time of the bioadhesive disk. Compared to the backing layer of Example 1, which was made of 12% by. weight hydroxyethyl cellulose (Mw 9 x 104), and which had an erosion time of about 21 minutes (See Table the backing layer of this Example, made from a combination of two grades of hydroxyethyl cellulose, had an erosion time of about 69 minutes (See Table 2).

EXAMPLE 6 A 100 ml solution for the non-adhesive backing layer was made using 87.98% by weight water USP, 0.02% by weight FD&C red 40 dye, 11.95% by weight hydroxyethyl -22cellulose (Mw 9 x 104), and 0.05% by weight of 40% glyoxal aqueous solution. The procedure of Example 1 was used, resulting in a 0.13 mm film.

Here, the glyoxal acted as a crosslinking agent, inducing a slow down in the erosion kinetics of the backing film. Compared to the backing layer of Example 1, which had no s glyoxal and which had an erosion time of about 21 minutes (See Table the backing layer of this Example, which incorporated glyoxal, had an erosion time of about 57 minutes (See Table 2).

EXAMPLE 7 to A 100 ml solution for the non-adhesive backing layer was made using 87.98% by weight water USP, 0.02% by weight FD&C red 40 dye, 11.8% by weight hydroxyethyl cellulose 0.1% by weight of 40% glyoxal aqueous solution, and 0.1% sweet peppermint flavor. Here, as in Example 6, the glyoxal acted as a crosslinking agent, inducing a slow down in the erosion kinetics of the backing film, compared with a backing layer with no Is glyoxal. The sweet peppermint was added as a flavoring agent. S EXAMPLE 8 As described in Example 1, the solutions.of.Examples 5, 6 and 7 were each castedon a polyester substrate. Instead of using a knife, ameier's bar was used to coatthe substrate.-.

The films were dried overnight at.90° C. The dried films were thicker, having a thickness of *.:..about 0.17 mm.

EXAMPLE 9 The solution of Example 1 was prepared in a beaker. A microslide was then dipped quickly into the solution until it was fully immersed, removed.from the solution, and left at room temperature for about 1 hour. The microslide was then dried overnight at 90° C. The resulting film was heterogeneous and had an average thickness of about 0.2 mm.

-23- EXAMPLE A 100 ml solution for the non-adhesive backing layer was made using 84% by weight water USP, 0.02% by weight FD&C red 40 dye, 11% by weight hydroxyethyl cellulose (Mw 9 x 104), 1% by weight hydroxyethyl cellulose (Mw 7 x 105), 0.1% by weight of a s glyoxal aqueous solution, 3% by weight glyoxal, and 1% by weight menthol. Here, the glyoxal acted as a crosslinking agent, inducing a slow down in the erosion kinetics of the backing film. Also, the mixture of two different grades of hydroxyethyl cellulose was used to achieve slow release of the menthol. The film was coated on a polyester film as previously described.

EXAMPLE 11 A 100 ml solution for the adhesive layer was made using 88.6% by weight water USP, by weight hydroxyethyl cellulose, Natrosol® 99-250 L NF (Aqualon), 2.6% by weight polyacrylic acid, Noveon® AA1 USP (BF Goodrich), 4.5% sodium carboxymethyl cellulose, S 15 cellulose gum 7 LF PH (Aqualon), and 2.5% by weight dyclonine HCI. Upon mixing, a suspension was formed.

Here, dyclonine HCI may be easily substituted with any other active pharmaceutical component. However, chemical characteristics of the active pharmaceutical, such as solubility, counter ions, and melting point, might require minor modifications of the overall process, such as dissolution in a particular solvent, changing the temperature of the solution, etc. The next example illustrates one slight modification.

EXAMPLE 12 A 100 ml solution for the adhesive layer was made using 74.6% by weight water USP, 1.8% by weight hydroxyethyl cellulose, 2.6% by weight polyacrylic acid, 4.5% sodium carboxymethyl cellulose, 2.5% by weight benzocaine, and 14% by weight ethyl alcohol. The use of benzocaine as the active pharmaceutical required that it first be dissolved in ethyl alcohol, given that benzocaine is more soluble in alcohol than water.

-24- In the final solution, the benzocaine tends to precipitate in the form of a very fine powder. However, the film characteristics and bioadhesive properties remain intact.

EXAMPLE 13 A 100 ml solution for the adhesive layer was made using 91% by weight water USP, 2% by weight hydroxyethyl cellulose, 2.5% by weight polyacrylic acid, and 4.5% sodium carboxymethyl cellulose. The composition of the adhesive layer may be modified and may vary according the ranges described in Table 1 below: TABLE 1 Item %w Material 1 60 to 99.5 Water USP 2 0.05 to 5 Hydroxyethyl cellulose 3 0.5 to 10 Polyacrylic acid 4 0.0 to 15 Sodium Carboxymethyl cellulose 5 0 to 10 Polyvinyl pyrrolidone The relative part of each components depends of the chemical compatibility of the.

components and the residence time to be obtained.

EXAMPLE 14 A 100 ml solution for the adhesive layer was made using 90% by weight water USP, 1% by weight butacaine sulfate, 2% by weight hydroxyethyl cellulose, 2.5% by weight polyvinyl pyrrolidone, and 4.5% by weight sodium carboxymethyl cellulose. The solution was coated using a knife over roll on a Mylar substrate.

EXAMPLE A 100 ml solution for the adhesive layer was made. The total composition of the solution was 48.6% water, 40% ethyl alcohol, 1.8% hydroxyethyl cellulose, 2.6% polyacrylic acid, 4.5% sodium carboxymethyl cellulose, and 2.5% dyclonine HCI. Here, however, the dyclonine HCI was first solubilized in 40 ml ethyl alcohol, and then, 48.6 ml of water were added to the dyclonine HCl/ethyl alcohol solution, followed by the addition of the other components.

The use of ethyl alcohol as an additional solvent resulted in a suspension which was slightly more viscous than that of Example 11, which used water as the only solvent.

EXAMPLE 16 Following the procedure of Example 12, a 100 ml solution for the adhesive layer was to prepared. The solution was then coated following the procedure used in Example 1. The resulting film was 0.12 mm thick.

EXAMPLE 17 Following the procedure of Example 12, a 100 ml solution for the adhesive layer was prepared. The solution was coated on top of a backing film prepared-according to Example 1.

The opening of the knife was adjusted, taking into account the thickness of the backing film.

After coating, the layered film was dried at 130 0 C for 15 minutes. A 0.27 mm layered film of two layers was formed.

EXAMPLE 18 Following the procedure of Example 14, a bioadhesive film was prepared, except that the film was not fully dried. A backing film was prepared according to Example 1. The backing film was peeled off of its substrate and laminated on top of the bioadhesive film while still moist, and pressure was applied to seal the two films together. The pressure applied on the films resulted in a good interfacial adhesion. A 0.38 mm layered film of two layers was formed.

-26a *aa.

a. EXAMPLE 19 Following the procedure of Example 1, several solutions for backing films were prepared according to the compositions of Table 2 below. Following film formation, V 2 inch disks were die cut and set on a double-sided tape. The tape was then positioned on a micro slide. The kinetics of erosion were evaluated in water: the slide was plunged into a 100 ml beaker of water stirred at a constant speed of 50 rpm. The time for erosion was measured from the moment the disk was fully immersed in the beaker of water. Percentages refer to the concentration in solution.

TABLE 2 Composition Weight Erosion Thickness (mm) Time (min.) 12% HEC (Mw 9 x 10 17.1 0.14 21 10% HEC (Mw 9 x 10") and 16.9/0.13 37 2% HEC (Mw 7 x 9% HEC (Mw 9 x 10") and 17 /0.14 3% HEC (Mw 7 x 10 5 11.75% HEC ((Mw9 x 10') and 17.1 0.14 69 0.25% HEC (Mw 1.3 x106) 11.95% HEC ((Mw 9 x 10") and 17.2 0.13 57 0.05% glyoxal (40% aq. sol.) 11.99% HEC ((Mw 9 x 10*) and 17.3 /0.14 0.01% propylene glycol The results demonstrate that the erosion time varies, depending on the components of the formulation, assuming a similar surface state for each sample. Although water does not mimic the exact composition of saliva, and this experiment cannot precisely replicate in vivo -27residence times, the experiment provides an in vitro comparison of erosion times of various compositions for use in practicing the present invention.

EXAMPLE 1/2 inch diameter disks having a thickness of between 0.19 and 0.21 mm were administered to six healthy volunteers. The backing layer was prepared according to Example 1, and the adhesive layer was prepared according to Example 15, some containing dyclonine HCl as the active pharmaceutical component, and others containing benzocaine as a substitute. The adhesive layer was coated on top of the backing layer, forming a layered disk. The layered disk was set in the mouth, and the time for erosion was measured from the moment the disk was set in place.

.i Participants were asked to evaluate the disk's handling and numbing effect on a scale of 0 to 3, with 3 being very good, 2 good, 1 fair, and 0 poor.: Participants also evaluated the time necessary for adhesion; the residence time; the foreign body sensation, if any, and its duration; and the erosion of the disk. Finally, participants were asked to evaluate the overall effectiveness of the disk and their overall impression, as well as which pharmaceutical component, dyclonine HCI or benzocaine they preferred. The results are described! in Table 3 below.

-28- TABLE 3 No. Handlin Adhesi Resi- Foreign Numb Disso- Effi- Over Pharma g on dence Body -ing lution cienc -all Time Sensatio y ceutical n Pref.

S 3 instant 1 hr 5 min. 3 did not B notice 2 2 instant 1 hr 5 min. 3 did not B notice 3 3 instant -45 no 2 did not D min. notice 4 3 instant -45 no 2 at the D min. end 5 2 instant 30 5 min. 3 at the D min. end 6 1 difficult -15 <5min. 2 did not D min. notice The results demonstrate that although the handling of the disk may be difficult for first time users, the adhesion is instantaneous, there is only a miinor foreign body sensation s which disappears after a couple minutes upon swelling of the disk, and numbing is effective.

EXAMPLE 21 A 1 kg preparation of a backing layer was made using 43.49% by weight of water, 43.49.% by weight of ethyl alcohol, 0.02% of FD&C red dye 40, 12% by weight of o1 hydroxyethyl cellulose (Mw 9 x 104) and 1% by weight of 40% glyoxal aqueous solution..

Then another 1 kg batch of the backing solution described at the example 1 was prepared.

Using a Werner Mathis Labcoater, the substrate (Mylar 1000D or other polyester films such -29as 3M ScotchPak 1022) was set. 90 ml of the backing layer solution prepared according to example 1 was set in front of a knife over roll with an opening of 0.7 mm. The solution was then casted on the substrate and film dried for 8-9 min. at 130° C. Following the drying step, a 0.09 mm thick reddish film was the result. Then, the backing solution first described in this s example was casted directly on the top of the first layer with the knife over roll technique using an opening of 0.8 mm. The resulting bilayer backing film was 0.15 mm thick.

EXAMPLE 22 A preparation of a backing layer obtained as described in example 5 was cast using a to knife over roll and dried for 8-9 min. at 1300 C. Then a preparation of a backing layer using 43.49% by weight of water, 43.49.% by weight of ethyl alcohol, 0.02% of FD&C red dye 12% by weight of hydroxyethyl cellulose (Mw 9 x 104) and 1% by weight of 40% glyoxal aqueous solution was coated directly on the top of the previous dry film (first layer was 0.05 mm thick) The resulting bilayer backing film was 0.12 mm thick.

EXAMPLE 23 When a crosslinking agent is incorporated in the formulation, thermal curing allows to further crosslink the material either before-or after the bioadhesive(s) layer(s) have been casted. Thermal curing of the films is performed by exposing the films to a time-temperature cycle. For instance, the film obtained at the end of example 22 might be exposed to 150 0

C

for 5 minutes, 120 0 C for 10 minutes or any temperature/time which would accommodate the stability requirements of the film's components.

EXAMPLE 24 A preparation of a backing layer obtained as described in example 5 was cast using a knife over roll and dried for 8-9 min. at 1300 C. A preparation of a backing layer using 42.49% by weight of water, 42.49.% by weight of ethyl alcohol, 0.02% of FD&C red dye 11% by weight of hydroxyethyl cellulose (Mw 9 x 104), 2% by weight of polyethylene glycol A ,1 6000 and 2% by weight of propylene glycol was coated directly on the top of the previous dry film (first layer was 0.06 mm thick) The resulting bilayer backing film was 0.12 mm thick.

EXAMPLE s A preparation of a backing layer using 42.49% by weight of water, 42.49.% by weight of ethyl alcohol, 0.02% of FD&C red dye 40, 10% by weight of hydroxyethyl cellulose (Mw 9 x 104), 4% by weight of hydropropylcellulose (Mw 5 105) was coated using a knife over roll technique. Then directly on the top of the previous dry film (first layer was 0.07 mm thick) a backing preparation made from 42.49% by weight of water, 42.49.% by weight of o1 ethyl alcohol, 0.02% of FD&C red dye 40, 12% by weight of hydroxyethyl cellulose (Mw 9 x i* 104) and 3% by weight of oleic acid, was casted and dried. The resulting bilayer backing film was 0.15 mm thick.

EXAMPLE 26 1s A preparation for the adhesive layer was made using 45.6% by weight water USP, •i 45% by weight of ehtyl alcohol, 2% by weight hydroxyethyl cellulose, Natrosol® 99-250 L NF (Aqualon), 2.9% by weight polyacrylic acid, Noveon® AA1 USP (BF Goodrich), and by weight of sodium carboxymethyl cellulose, cellulose gum 7 LF PH (Aqualon). This preparation is a bioadhesive preparation but does not contain.ahy pharmaceutical.

EXAMPLE 27 A 100 ml solution for the adhesive layer was made using 45.1% by weight of water USP, 45% by weight of ehtyl alcohol, 1.8% by weight hydroxyethyl cellulose, Natrosol® 99- 250 L NF (Aqualon), 2.6% by weight polyacrylic acid, Noveon® AA1 USP (BF Goodrich), 4.5% sodium carboxymethyl cellulose, cellulose gum 7 LF PH (Aqualon), and 1% by weight terbutaline sulfate.

-31 EXAMPLE 28 The film obtained following the example 25 is used as substrate for the final multilayer film of this example. The bioadhesive preparation of example 26 is directly casted on the film of example 25 and dried. Then the preparation of example 27 is cast on the top s with a knife over roll system. The final four layer film is 0.240 mm. The composition of this film limits the release ofterbutaline in the oral cavity but not completely as the pharmaceutical can still diffuse through the sides. In order to avoid this side diffusion, we have to changed slightly the design has previously mentioned.

1o EXAMPLE 29 The film obtained following the example 25 is used as substrate for the final multilayer film of this example. The bioadhesive preparation-of example 26 is.directly casted on the film of example 25 and dried. A trilayer film is thus obtained, the last layer being bioadhesive but not containing any drug. Then the preparation of example 27 is coated using a mask and dried (the mask is a 0.500 mm polyester film in which ellipsoids have been die.

cut deposited on the trilayer laminate). This step can be repeated if necessary. The mask is then delaminated. The resulting film is tri/four layers film composed of a laminate backing layer and a laminate bioadhesive layer in which the final component includes the pharmaceutical and is of a smaller surface as shown in figure. With this system, diffusion by either the sides or the back side is limited and allows an unidirectional release of the drug into the mucosal tissues.

o: EXAMPLE Following the previous example but with fluocinonide instead of pilocarpine HC1, the same type of film is constructed using a screen coating technique instead of using a mask.

Others techniques such as deposition of, spraying the solution or die cutting off the last layer are satisfactory.

Claims (15)

1. A pharmaceutical carrier device comprising a layered flexible film having a first water-erodible adhesive layer to be placed in contact with a mucosal surface, a second water-erodible non-adhesive backing layer, and optionally a pharmaceutical incorporated with said first layer, said second layer, or both layers, wherein said first water-erodible adhesive layer comprises a film-forming polymer and a bioadhesive polymer, and is free of a plasticizer, and wherein said second water-erodible non-adhesive backing layer comprises hydroxyethyl cellulose.

2. The pharmaceutical carrier device of claim 1, wherein said first water-erodible layer comprises an alkyl cellulose or hydroxyalkyl cellulose and a bioadhesive polymer.

3. The pharmaceutical carrier device of claim 1, wherein said first water-erodible adhesive layer comprises a film forming polymer selected from hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl methyl cellulose, polyvinyl alcohol, polyethylenglycol, 20 polyethylene oxide, ethylene oxide-propylene oxide co-polymers, collagen and derivatives, gelatin, albumin, polyaminoacids and derivatives, polyphosphazenes, polysaccharides and derivatives, or chitin and chitosan, alone or in combination, and a bioadhesive polymer selected from polyacryliacid, polyvinyl pyrrolidone, or sodium carboxymethyl cellulose, alone or in combination.

4. The pharmaceutical carrier device of any one of claims 1 to 3, wherein a pharmaceutical is incorporated with said first water-erodible adhesive layer.

5. The pharmaceutical carrier device of any one of claims 1 to 4, wherein said layered film has two layers and total thickness of from 0.1 mm to 1 mm.

6. The pharmaceutical carrier device of any one of claims 1 to 5, which further comprises a third layer between said first water-erodible adhesive layer and said second water-erodible non-adhesive backing layer and wherein said third layer is a water-erodible, adhesive layer which has a surface area sufficient to encompass said first water-erodible adhesive layer and contact the mucosal surface.

7. The pharmaceutical carrier device of any one of claims 1 to 6, wherein one or more of the layers further comprises a component which acts to adjust the kinetics of the erodibility of the device.

8. The pharmaceutical carrier device of claim 7, wherein the component is a water-based emulsion of polylactide, polyglycolide, lactide-glycolide co- polymers, poly-s-caprolactone, polyorthoesters, polyanhydrides, ethyl cellulose, vinyl acetate, cellulose acetate, or polyisobutylene, alone or in combination.

9. The pharmaceutical carrier device of any one of claims 1 to 8, wherein said pharmaceutical incorporated within said first water-erodible adhesive layer, said second water-erodible non-adhesive backing layer, or both layers comprises an anti-inflammatory analgesic agent, a steroidal anti-inflammatory agent, an antihistamine, a local anaesthetic, a bactericide, a disinfectant, a vasoconstrictor, a hemostatic, a chemotherapeutic drug, an antibiotic, a keratolytic, a cauterising agent, an antiviral, an antirheumatic, an antihypertensive, a broncholidator, an 20 anticholinergic, an antiemetic, a hormone, a macromolecule, a peptide, a protein, or a vaccine alone or in combination.

The pharmaceutical carrier device of claim 1, wherein said first water-erodible adhesive layer comprises hydroxypropyl cellulose, hydroxyethyl cellulose, polyacrylic acid, and sodium carboxymethyl cellulose; said second water-erodible non-adhesive backing layer comprises hydroxyethyl cellulose; and wherein said pharmaceutical comprises dyclonine HC1.

11. The pharmaceutical carrier device of any one of claims 1 to 10 wherein the carrier device has a solvent content of from about 1 to about 15% by weight.

12. A layered flexible film disk which adheres to mucosal surfaces for the localised delivery of pharmaceutical, comprising a first water-erodible adhesive layer and a second water-erodible non-adhesive backing layer, wherein said pharmaceutical or combination of pharmaceuticals is incorporated with said first water-erodible adhesive layer, or said second water-erodible non-adhesive backing layer, or both said first adhesive water-erodible layer and said second non-adhesive backing layer, and wherein said first water-erodible ahdesive layer comprises a film-forming polymer and a bioadhesive polymer, and is free of a plasticizer, and wherein said second water-erodible non-adhesive backing layer comprises hydroxyethyl cellulose, said layered flexible film having a total thickness of from 0.1 mm to 1 mm.

13. The layered flexible film disk of claim 12, wherein said pharmaceutical or combination of pharmaceuticals comprises an anti-inflammatory analgesic agent, a steroidal anti-inflammatory agent, an antihistamine, a local anaesthetic, a baceteride, a disinfectant, a vasoconstrictor, a hemostatic, a chemotherapeutic drug, an antibiotic, a keratolytic, a cauterising agent, an antiviral, an antirheumatic, an antihypertensive, a broncholidator, an anticholinergic, an antiemetic, a hormone, a macromolecule, a peptide, a protein, or a vaccine, alone or in combination.

14. A pharmaceutical carrier device substantially as hereinbefore described with particular reference to the examples and/or the preferred embodiments and excluding, if any, comparative examples.

15. A layered flexible film disk substantially as hereinbefore described with particular reference to the examples and/or the preferred embodiments and excluding, if any, comparative examples. Dated this twenty-eighth day of October 2003 ViroTex Corporation Patent Attorneys for the Applicant: F B RICE CO