An adhesive wafer with GEL-forming layer

Abstract

An adhesive wafer is provided for securing an ostomy device to the skin of a patient. When the adhesive wafer is exposed to moisture – a second gel-forming layer has a swelling rate, which is higher than a first skin adhesive layer. A mouldable protective seal for placement between a user's skin and an adhesive wafer of an ostomy device is also provided.

Description

[0001] AN ADHESIVE WAFER WITH GEL-FORMING LAYER

[0002] TECHNICAL FIELD

[0003] The present invention relates to an adhesive wafer for an ostomy appliance.

[0004] SUMMARY

[0005] One aspect of the disclosure provides an adhesive wafer in accordance with the appended claim 1, and a protective seal according to claim 23.

[0006] WO 2023 / 208303 describes a composition for sealing around a stoma. WO2018 / 054442 describes an adhesive ostomy element.

[0007] BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are included to provide a further understanding of embodiments and are incorporated into and a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated, as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.

[0009] Fig. 1A shows a schematic cross-section of an adhesive wafer before use

[0010] Fig. IB shows a schematic cross-section of the adhesive wafer of Figure 1A, placed on the skin of a wearer while in use

[0011] Fig. 2A shows a schematic cross-section of a further adhesive wafer before use

[0012] Fig. 2B shows a schematic cross-section of the adhesive wafer of Figure 2A, placed on the skin of a wearer while in use

[0013] Figs 3A-3D show schematic cross-section of various adhesive wafers, before use

[0014] Fig. 4A shows a schematic cross-section of a further adhesive wafer before use Fig. 4B shows a schematic cross-section of the adhesive wafer of Figure 4A, placed on the skin of a wearer while in use

[0015] Fig. 4C shows a schematic cross-section of an alternative adhesive wafer, placed on the skin of a wearer while in use

[0016] Figs 5A-5B show schematic cross-sections of various adhesive wafers, before use

[0017] Figs 6A-6D show schematic cross-sections of various protective seals, before use

[0018] Figs 7A-7B show schematic cross-sections of various protective seals, before use

[0019] Fig. 8 shows a protective seal according to Figure 7A located between an adhesive wafer and the skin of a wearer

[0020] Fig. 9 illustrates results of expansion rate measurements

[0021] DETAILED DESCRIPTION

[0022] In the following, whenever referring to the proximal side of a device or part of a device, the referral is to the skin-facing side, when the wafer or ostomy appliance is worn by a user.

[0023] Likewise, whenever referring to the distal side of a device or part of a device, the referral is to the side facing away from the skin, when the wafer or ostomy appliance is worn by a user. In other words, the proximal side is the side closest to the user, when the wafer is fitted on a user and the distal side is the opposite side - the side furthest away from the user during use.

[0024] An axial direction is defined as the direction of the stoma, when the appliance is worn by a user. Thus, the axial direction is substantially perpendicular to a skin surface of a user, such as an abdominal skin surface. A radial direction is defined as transverse to the axial direction.

[0025] In the following, the words "ostomy" and "stoma" are used interchangeably without any intention to have different meanings.

[0026] By output is herein meant the effluent from a stoma, being faeces and / or urine in a more or less viscous form or mucins secreted from the epithelial layer of the alimentary canal. In the case of a colostomy, the output may be quite solid, whereas an ileostomy may produce more liquid output. The output may contain digestive fluids with enzymes and other components that may be aggressive to the skin and thus may cause maceration and contact dermatitis of the skin if brought into contact with it as well as the output may comprise components that may attack and degrade the adhesive.

[0027] The term "water-swellable" refers to a layer which is able to expand upon contact with fluids e.g. water-containing fluids such as ostomy output. Swelling is caused by water physically entering the layer and causing an increase in volume. The speed of water-swelling is determined by the swelling speed test method described herein.

[0028] An adhesive wafer for securing an ostomy device to the skin of a patient is thus provided, said adhesive wafer comprising: a first water-swellable skin-adhesive layer, and a second non-adhesive, water-swellable gel-forming layer, wherein - when the adhesive wafer is exposed to moisture - the second gel-forming layer has a swelling rate, preferably when measured as according to the swelling speed test method A described in the specification, which is higher than said first skin adhesive layer.

[0029] An adhesive wafer acts to adhere an ostomy appliance, or a component of an ostomy appliance, to the skin of a wearer. The adhesive wafer may be a part of an ostomy appliance comprising a collecting bag. The collecting bag may be detachably or permanently attached to the adhesive wafer along a connection zone circumferencing the bag inlet.

[0030] When fitting an adhesive wafer to the area around a stoma, there will be a peristomal gap between the edge of the hole in the adhesive wafer and the stoma itself. Output which flows into the peristomal gap may lead to maceration of the skin and degradation of the adhesive, resulting in leakage, unintended detachment of the wafer and discomfort to the user.

[0031] The second, non-adhesive water-swellable gel-forming layer in the adhesive wafer can swell rapidly, helping to seal the peristomal gap within a short time period (e.g. 2-30 minutes).

[0032] The first skin-adhesive layer may swell more slowly, which also helps to seal the peristomal gap in a secure manner.

[0033] Suitably, the adhesive wafer comprises opposing distal and proximal surfaces and a through- hole from said distal surface to said proximal surface for accommodating a stoma. The adhesive wafer may have an outer periphery which is substantially circular, or oval in shape. Swelling of both first and second layers suitably takes place primarily in the direction of the through-hole of the adhesive wafer. Additional film layers within the adhesive wafer, and / or on the distal or proximal surfaces thereof, can be used to control the swelling direction. Suitably, said film layers comprise a plastically deformable film material.

[0034] Suitably, the distal surface of the adhesive wafer comprises or consists of the second gelforming layer, and the proximal surface of the adhesive wafer comprises or consists of the first skin adhesive layer. In this manner, the second gel-forming layer and the first skin adhesive layer form the outer surfaces of the adhesive wafer and are exposed during use.

[0035] The second gel-forming layer suitably has a swelling rate, when measured as according to the swelling speed test method described in the specification, which is at least two times greater than, preferably at least five times greater than, more preferably at least 10 times greater, than the swelling rate of said first skin adhesive layer. This ensures that expansion of the second gel-forming layer takes place within a suitable timeframe for a wearer.

[0036] The first skin adhesive layer and the second gel-forming layer may be arranged adjacent each other, and preferably directly adjacent each other, in the adhesive wafer. This means that there is no intervening layer or element between the first and second layers, and the layers can exert force on one another.

[0037] First water-swellable skin-adhesive layer

[0038] The first water-swellable skin-adhesive layer acts to adhere the adhesive wafer to the skin of the user. It suitably comprises a polymer comprising monomer units selected from the group consisting of styrene, isoprene, butadiene, ethylene, and butylene. In embodiments, the skin-adhesive layer comprises a styrene block co-polymer. In embodiments, the skinadhesive layer comprises a styrene block co-polymer selected from the group consisting of styrene-isoprene-styrene (SIS), styrene-butadiene- styrene (SBS), styrene-isobutylene- styrene (SIBS), and styrene-ethylene / butylene-styrene (SEBS).

[0039] In embodiments, the skin-adhesive layer comprises a polyethylene copolymer.

[0040] In embodiments, the skin-adhesive layer comprises a polyethylene copolymer selected from the group consisting of ethylene vinyl acetate, ethylene vinyl acetate carbon monoxide, ethylene butyl acetate, ethylene vinyl alcohol, ethylene butyl acrylate, ethylene butyl acrylate carbon monoxide, and combinations thereof. In embodiments, the skin-adhesive layer comprises polyisobutylene (PIB). In embodiments, the skin-adhesive layer comprises absorbent material selected from the group consisting of hydrocolloids, microcolloids, salt, and super absorbent particles.

[0041] In embodiments, the skin-adhesive layer comprises an absorbent material in an amount of 1- 60% (w / w) of the layer. For instance, the layer comprises an absorbent material in an amount of 1-40% (w / w) or 1-20% (w / w) or 20-40% (w / w) or 20-60% (w / w) or 40-60% (w / w) or 25- 50% (w / w) of the layer. In embodiments, the absorbent material is selected from hydrocolloid, water soluble salt, mono, di- and oligosaccharides. In embodiments, the hydrocolloid is selected from guar gum, locust bean gum, pectin, potato starch, alginates, gelatine, xantan or gum karaya, cellulose derivatives, salts of carboxymethyl cellulose, sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, sodium starch glycolate, polyvinylalcohol, and mixtures thereof.

[0042] The dimension of the first skin adhesive layer in a direction away from the stomal through- hole may be greater than the dimension of the second gel-forming layer in said direction. This provides that the first skin adhesive layer can be exposed on both proximal and distal surfaces of the adhesive wafer, as illustrated in Figures 1-4.

[0043] Second non-adhesive, water-swellable gel-forming layer

[0044] In use, the gel-forming layer expands more rapidly than the first skin-adhesive layer and provides a seal about the stoma. The gel-forming layer is substantially non-adhesive. By non- adhesive is meant that it cannot support its own weight when adhered to a vertical surface.

[0045] The gel-forming layer suitably has a thickness of between 0.1 and 3mm. The gel-forming layer suitably has an extension radially from the through-hole of between 10 and 50mm.

[0046] The gel-forming layer typically comprises a clay, such as a smectite clay, preferably bentonite or laponite, more preferably laponite. The clay acts to absorb water, and thus expand the gel-forming layer.

[0047] The gel-forming layer suitably comprises a matrix material, in which said clay is dispersed. The matrix material may be a polymer matrix. Suitable polymer matrixes include polypropylene (PP), polybutene (PB) or blends thereof. Additional components of the matrix material include hydrophilic polymers, e.g. polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and ethylene vinyl acetate (EVA), and hydrocolloids such as starch, CMC or gelatine. The gel-forming layer may - alternatively or additionally - comprise superabsorbent material, e.g. superabsorbent polymer (SAP). Known superabsorbent polymers include polymers and co-polymers of acrylic acid, acrylic acid esters (e.g. methyl acrylate) and acrylic acid salts.

[0048] In one aspect, the gel-forming layer may comprise or consist of a nonwoven layer of superabsorbent fibres (SAF). Such a layer may be made by airlaying or needling fibres of superabsorbent material to form said nonwoven layer. The use of a nonwoven layer can be beneficial, as it provides good flexibility, while maintaining good liquid absorption.

[0049] Third non-adhesive water-swellable gel-forming layer

[0050] The adhesive wafer may further comprise a third non-adhesive water-swellable gel-forming layer, wherein - when the adhesive wafer is exposed to moisture - the third gel-forming layer has a swelling rate, when measured as according to the swelling speed test method described in the specification, which is higher than the swelling rate of the second gelforming layer. The third non-adhesive water-swellable gel-forming layer allows flexibility in the construction and design of the adhesive wafer. In particular, a rapidly-swelling third gelforming layer can form a peristomal seal quickly, followed by an additional seal formed by the second gel-forming layer.

[0051] Suitable materials and form of the third gel-forming layer are the same as those provided above for the second gel-forming layer.

[0052] The third gel-forming layer may be arranged between said first skin adhesive layer and said second gel-forming layer. Alternatively, the second gel-forming layer may be arranged between the third gel-forming layer and the first skin adhesive layer. Preferably the second gel-forming layer is arranged between the third gel-forming layer and the first skin adhesive layer.

[0053] In embodiments, the second gel-forming layer is located at least in a first region of said adhesive wafer which extends radially from the stomal through-hole, wherein the third gelforming layer is located at least in a second region of said adhesive wafer, said first region and said second region being located concentrically on the first skin adhesive layer. In this arrangement, second and third gel-forming layers are located at least partly adjacent one another in the plane of the adhesive wafer, rather than being layered on top of one another. This arrangement can provide a thinner adhesive wafer, in which similar swelling and sealing properties are achieved than a three-layer structure. A film layer may be arranged between the first skin adhesive layer, and the second gelforming layer, and / or on an external surface of the second gel-forming layer. Placement of film layers between the first and second layers allows the second gel-forming layer to expand more freely, as the film layer provides low friction surfaces, across which the first and second layers may glide. Additionally, a film layer may improve the structural integrity of the adhesive wafer. When a third gel-forming layer is present, the film layer may be arranged between the first skin adhesive layer and the second gel-forming layer, or between the first skin adhesive layer, and the third gel-forming layer, or in both of these locations.

[0054] The adhesive wafer may, additionally or alternatively, comprise a film layer arranged at at least one location selected from: between the first skin adhesive layer and the second gel-forming layer, between the second adhesive layer and the third gel-forming layer and on an external surface of the third gel-forming layer.

[0055] Said film layer, or film layers, may comprise a plastically deformable film material. In embodiments, the plastically deformable film material can comprise a Parafilm material from the company Amcor pic.

[0056] Furthermore, a release liner may be arranged on the proximal surface of the adhesive wafer. The release liner ensures that the properties of the adhesive are preserved and that the adhesive surface is not laid open until just before use. The release liner may suitably be a siliconised or fluorinated release liner, such as a siliconised or fluorinated craft paper, polyethylene, polypropylene or polyethylene terephthalate film. Suitably, the release liner is a siliconised polyethylene film, such as medium density polyethylene from the company Loparax.

[0057] Suitably, each of said first skin adhesive layer, second gel-forming layer and said third gelforming layer (where present) has a circular through-hole, and preferably wherein each of the circular through-holes have the same diameter and wherein the inner surface of each circular through-hole in one layer is aligned with the inner surface of each circular through- hole in an adjacent layer.

[0058] The adhesive wafer may further comprise a second skin-adhesive adhesive layer, arranged such that at least the second gel-forming layer, and preferably the third gel-forming layer, is / are located between the first skin-adhesive layer and the second skin-adhesive adhesive layer. Suitably, the second skin-adhesive layer is located at the distal surface of the adhesive wafer. The use of first and second skin-adhesive layers allows adhesion of the adhesive wafer on both faces thereof, and flexibility in the construction. Suitable materials for the second skin-adhesive layer are as set out above for the first skin-adhesive layer. The second skinadhesive layer may also be water-swellable. A release liner may be arranged on an external surface of the second skin-adhesive layer.

[0059] The second and / or the third gel-forming layers of the adhesive wafer suitably comprise a clay, such as a smectite clay, preferably montmorilonite, bentonite or laponite, more preferably laponite.

[0060] The ostomy device may be a 1-part or a 2-part device. It typically comprises a collecting bag, arranged to collect stomal output. The collecting bag usually comprises a front wall on the distal side and a rear wall on the proximal side. The walls may be made of gas- and liquid impermeable foil-material (for example of polyethylene (PE), polyvinyl-chloride (PVC) or ethylene-vinyl-acetate (EVA)) that is welded around the edges or the rim, so as to form a pouch defining a waste collection chamber. The bag may be welded only partly around the rim so that an opening for emptying the bag is provided at the bottom of the bag. In that case, the bag may be provided with means for closing that opening. A waste inlet opening is provided in the rear wall and placed in the upper part of the collecting bag, so that when a user stands up, the waste inlet opening will be above the midline of the collecting bag. This leaves a larger collecting volume below the waste inlet opening.

[0061] A mouldable protective seal is also provided. The protective seal is suitable for placement between a user's skin and an adhesive wafer of an ostomy device, so as to provide an extra layer of security and reduce the opportunity for leakages. Protective seals (also called "barrier rings") are often provided as accessories for users. In use, the protective seals can be moulded to fit around a stoma, and then an adhesive wafer of an ostomy device may be placed over the protective seal. The extension of the adhesive wafer is therefore greater than that of the protective seal.

[0062] The protective seal is mouldable. This means that it can be formed to a particular shape, using the fingers, yet retains its integrity. Therefore, all layers which comprise the mouldable protective seal are themselves mouldable.

[0063] The mouldable protective seal comprises a first skin-adhesive seal layer, and a second non-adhesive, water-swellable gel-forming layer, and optionally, a third non-adhesive water-swellable gel-forming layer.

[0064] The protective seal comprises opposing distal and proximal surfaces and a through-hole from said distal surface to said proximal surface, for accommodating a stoma. The proximal surface of said protective seal is comprised by the first skin adhesive layer. The protective seal is essentially ring-shaped.

[0065] When the protective seal is exposed to moisture - the second gel-forming layer has a swelling rate, preferably when measured as according to the swelling speed test method A described in the specification, which is higher than said first adhesive seal layer. When the protective seal is exposed to moisture - the third gel-forming layer has a swelling rate, preferably when measured as according to the swelling speed test method A described in the specification, which is higher than the swelling rate of the second gel-forming layer.

[0066] Suitably, the first skin adhesive layer, the second gel-forming layer and the third gel-forming layer are co-extensive in the plane of said protective seal. The term "co-extensive" means having the same extension in said plane; i.e. overlapping.

[0067] The protective seal may further comprise a second adhesive layer, wherein the distal surface of said protective seal is comprised by the second adhesive layer. Optionally, the first adhesive seal layer, the second gel-forming layer, the third gel-forming layer and the second adhesive layer are co-extensive in the plane of said protective seal. Arranging the layers in a coextensive manner provides a regular form of the protective seal.

[0068] Suitable, in the protective seal, a film layer is arranged between the first skin adhesive layer, and the second gel-forming layer, and / or on an external surface of the second gel-forming layer. The film layer provides the second gel-forming layer to expand more freely, as the film layer provides low friction surfaces, across which the first and second layers may glide.

[0069] Additionally, a film layer may improve the structural integrity of the protective seal.

[0070] A release liner may be arranged on an external surface of the first skin adhesive layer and / or on an external surface of the second skin-adhesive layer. The second and / or the third gelforming layers of the protective seal suitably comprise a clay, such as a smectite clay, preferably montmorilonite, bentonite or laponite, more preferably laponite. Embodiments, and features of the various exemplary embodiments described in this application, may be combined with each other ("mixed and matched"), unless specifically noted otherwise.

[0071] Detailed Description of the Drawing

[0072] In the following detailed description, reference is made to the accompanying drawings. The drawings form a part of this specification and illustrate exemplary embodiments for practicing the invention. Directional terminology, such as "top," "bottom," "front," "back," etc., is used with reference to the orientation of the figures being described. Because components of embodiments can be positioned in a number of orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the invention. The detailed description describes examples for practicing the invention and is not to be read to limit the scope of the invention. The scope of the invention is defined by the attached claims.

[0073] Fig. 1A shows a schematic cross-section of an adhesive wafer (100) before use comprising a first water-swellable skin-adhesive layer (110), and a second non-adhesive, water-swellable gel-forming layer (120). The adhesive wafer (100) comprises opposing distal (101) and proximal (102) surfaces and a through-hole (103) from said distal surface (101) to said proximal surface (102) for accommodating a stoma. Film layers (105) are arranged between the first skin adhesive layer (110), and the second gel-forming layer (120), and on the distal surface (101). Release liner (107) is arranged on the proximal surface (102).

[0074] Fig. IB shows a schematic cross-section of the adhesive wafer of Figure 1A, placed on the skin (10) of a wearer while in use, around a stoma (S). As can be seen the second gelforming layer (120) swells and expands into the peristomal gap before the first skin adhesive layer (110) does.

[0075] Fig. 2A shows a schematic cross-section of a further adhesive wafer before use comprising - in order - a first water-swellable skin-adhesive layer (110), a second non-adhesive, water- swellable gel-forming layer (120) and a third non-adhesive water-swellable gel-forming layer (130). Remaining components of the wafer of Figure 2A are as referenced in Figure 1A.

[0076] Fig. 2B shows a schematic cross-section of the adhesive wafer of Figure 2A, placed on the skin (10) of a wearer while in use, around a stoma (S). As can be seen, third non-adhesive water-swellable gel-forming layer (130) expands into the peristomal gap before the second gel-forming layer (120) and the first skin adhesive layer (110). Remaining components of the wafer of Figure 2B are as referenced in Figure IB.

[0077] Figs 3A-3D show schematic cross-section of various adhesive wafers, before use. The wafer of Figure 3A has the same arrangement of first water-swellable skin-adhesive layer (110), second non-adhesive, water-swellable gel-forming layer (120) and third non-adhesive water- swellable gel-forming layer (130) as in Figure 2A, and further includes a film layer (105) between the second non-adhesive, water-swellable gel-forming layer (120) and the third non-adhesive water-swellable gel-forming layer (130).

[0078] In the wafer of Figure 3B the third non-adhesive water-swellable gel-forming layer (130) is arranged between the first water-swellable skin-adhesive layer (110) and the second non- adhesive, water-swellable gel-forming layer (120).

[0079] The wafer of Figure 3C has the same arrangement of layers as in Figure 3A. The third non- adhesive water-swellable gel-forming layer (130) is recessed slightly from the through-hole (103).

[0080] The wafer of Figure 3D has the same arrangement of layers as in Figure 3A and 3C. The third non-adhesive water-swellable gel-forming layer (130) has a smaller extension in the direction away from the through-hole (103) than the other layers.

[0081] Fig. 4A shows a schematic cross-section of a further adhesive wafer before use. It comprises - in order - a first water-swellable skin-adhesive layer (110), a second non-adhesive, water- swellable gel-forming layer (120) and a third non-adhesive water-swellable gel-forming layer (130). Second skin-adhesive adhesive layer (140) is present on the distal surface of the third non-adhesive water-swellable gel-forming layer (130), and has a larger extension in the direction away from the through-hole (103) than the other layers. In this manner, both the first skin adhesive layer and the second adhesive layer can make sufficient contact with the skin of the wearer.

[0082] Fig. 4B shows a schematic cross-section of the adhesive wafer of Figure 4A, placed on the skin of a wearer while in use. The third non-adhesive water-swellable gel-forming layer (130) expands into the peristomal gap before the second gel-forming layer (120) and the first skin adhesive layer (110).

[0083] Fig. 4C shows a schematic cross-section of an alternative adhesive wafer, placed on the skin of a wearer while in use. In this figure, the placement of second and third gel-forming layers is reversed. Figs 5A-5B show schematic cross-sections of various adhesive wafers, before use. In these figures, the second and third gel-forming layers (120, 130) are located at least partially in the same plane. In Figure 5A, third non-adhesive water-swellable gel-forming layer (130) is arranged closer to the through-hole (103) than the second non-adhesive water-swellable gelforming layer (120). In use, the third non-adhesive water-swellable gel-forming layer (130) expands first, forming a seal about the stoma. Subsequently, the second non-adhesive water-swellable gel-forming layer (120) expands, to reinforce the seal about the stoma. The arrangement of Figure 5B is similar to that of Figure 5A. The third non-adhesive water- swellable gel-forming layer (130) gradually thins as it extends from the through-hole, while the second non-adhesive water-swellable gel-forming layer (120) becomes thicker. In use, the functionality of the wafer of Figure 5B is similar to that of Figure 5A.

[0084] Figs 6A-6D show schematic cross-sections of various protective seals, before use. The seal of Figure 6A comprises - in order - a first skin-adhesive seal layer (210), third non-adhesive water-swellable gel-forming layer (230), and a second non-adhesive, water-swellable gelforming layer (220). The protective seal (200) comprises opposing distal (201) and proximal (202) surfaces and a through-hole (203) from said distal surface (201) to said proximal surface (202) for accommodating a stoma. The proximal surface (202) of said protective seal (200) is comprised by the first skin adhesive layer (210), and a release liner (207) is arranged on an external surface of the first adhesive seal layer (210). Film layer (205) is arranged between the first adhesive seal layer (210), and the third gel-forming layer (230), and on the external surface of the second gel-forming layer (220).

[0085] The seal of Figure 6B is the same as that of Figure 6A, but does not include film layer (205) on the external surface of the second gel-forming layer (220).

[0086] The seal of Figure 6C is the same as that of Figure 6B, additionally comprising second adhesive layer (240), at the distal surface (201) of said protective seal (200). A release liner (207) is arranged on an external surface of the second skin-adhesive layer (240).

[0087] The seal of Figure 6D is the same as that of Figure 6C, wherein the order of the third non- adhesive water-swellable gel-forming layer (230), and the second non-adhesive, water- swellable gel-forming layer (220) is reversed.

[0088] Figs 7A-7B show schematic cross-sections of various protective seals, before use. The protective seal (200) of Figure 7A comprises - in order - first skin-adhesive seal layer (210), second non-adhesive, water-swellable gel-forming layer (220) and second adhesive layer (240). Release liners (207) are arranged on both external surfaces of the protective seal (200). Film layers (205) are arranged between the first adhesive seal layer (210), and the second gel-forming layer (220), and between the second adhesive seal layer (240), and the second gel-forming layer (220).

[0089] The protective seal (200) of Figure 7B has a construction similar to that of Figure 7A. This seal (200) only comprises second gel-forming layer (220) in a limited region of the seal, adjacent to the through-hole (203).

[0090] Fig. 8 shows a protective seal according to Figure 7A located between an adhesive wafer (W) and the skin (10) of a wearer.

[0091] Fig. 9 illustrates the results of the expansion rate measurements.

[0092] EXAMPLES

[0093] Swelling speed test method A

[0094] Swelling speed was tested by hot pressing the composition to be tested at 90 °C for 30 sec to a thickness of 1 mm between sheets of release liner (siliconized paper). From this, a ring (outer diameter 57 mm, hole diameter 27 mm) was cut. A hard plastic (polyoxymethylene, "POM") disc (diameter 17 mm, 3 mm thick) was attached with double sided adhesive tape in the center of a glass petri dish. The ring of swellable composition was mounted in the glass petri dish centred around the POM disc to give a 5 mm gap between the POM and the ring of swellable composition. When isotonic saline is added to sample to initiate swelling, the process is an inherently low contrast event. To increase contrast, crossed polarizing filters were used : A sheet of polarizing film was attached to a light table. The sample was placed on top of this film. A camera (Canon EOS 12000) was mounted to observe sample from above. On the lens of the camera was mounted another polarizing filter. This filter was then adjusted to let the least amount of light through (this happens when the 2 filters are at 90° orientation to each other). First picture of sample was taken, saline was added to cover the ring and subsequent pictures were taken at pre-determined time points, such as 1-24 hours. The gap between the ring and the POM disc at positions 12-3-6-9 o'clock was now measured using Image], both at start (tO) and at later time points. The average change in gap size was calculated and reported in mm at the different time points.

[0095] FORMULATION 1

[0096] A second gel-forming layer (slow)- approximately 3 mm / h

[0097] FORMULATION 2

[0098] The third gelforming layer (fast) app. 10-20 mm / h FORMULATION 3

[0099] Another example of a fast third gel forming layer is:

[0100] All formulations can be produced in a lab speedmixer in 100 g scale, after mixing at ambient temperature for 5 min at a speed of 3500 rpm. Expansion Rate Measurements

[0101] Expansion rate measurements were performed as follows: Sample Pressing:

[0102] The sample material was pressed between two silicone release liners. A distance bar was inserted to obtain a sample of 1 mm thickness. The sample was pressed at a temperature of 90 °C to achieve consistent lamination at 10 bar for 30 sec.

[0103] Liner Replacement:

[0104] After pressing, one of the silicone release liners was carefully removed. This was replaced with a polyurethane (PU) film, ensuring full contact with the sample surface.

[0105] Sample Preparation:

[0106] Circular samples having an inner diameter of 50 mm and an outer diameter of 80 mm were cut out using a precision punch tool.

[0107] Transfer to Petri Dish:

[0108] The remaining silicone release liner was removed, and the sample placed onto a petri dish for testing. A ruler was placed on the back side of the petri dish to be able to measure the expansion of the gel with time.

[0109] Outer Diameter Sealing :

[0110] Double-sided adhesive tape was applied around the outer diameter of the sample to ensure a sealed outer perimeter.

[0111] Stoma Placement:

[0112] An artificial stoma (0 20 mm) was positioned centrally within the inner diameter of the sample. The stoma was secured using double-sided adhesive tape to maintain alignment and adhesion.

[0113] Testing:

[0114] Saline water was added to the sample in the petri dish and a camera used to monitor the sample by taking a photo every 5 min. Data for gel times of 5,10,30,60,120,180 and 240 min were recorded.

[0115] Test results for 4 compositions are provided in Figure 9:

[0116] Mio Ipc is a PIB hydrocolloid-based adhesive.

[0117] Mio 2pc is a PIB-resin hydrocolloid-based adhesive for extended wear. Mio 1 pc and Mio 2 pc are adhesive compositions that are formulated to swell (expand) very slowly. This relatively slow speed of expansion is needed to maintain adhesion and dry skin throughout the wear time. The swelling of Mio Ipc is faster than that of the Mio 2pc, which reflects the fact that Mio 1 pc is used for shorter wear time than the Mio 2 pc that are intended a longer wear time. After 4h of testing, the expansion of these compositions remains low (below 2mm)

[0118] Forml (Formulation 1) and Form2 (Formulation 2) are non-adhesive, water-swellable gelforming compositions according to the Examples above. The slow swelling Forml provides expansion of ca. 3 mm pr hour and protects the skin with a firm gel. Form2 is a fast swelling formulation with an expansion of ca. 15 mm pr hour. Form2 will cover the skin gap much faster than Forml.

Claims

CLAIMS1. An adhesive wafer (100) for securing an ostomy device to the skin of a patient, said adhesive wafer (100) comprising : a first water-swellable skin-adhesive layer (110), and a second non-adhesive, water-swellable gel-forming layer (120), wherein - when the adhesive wafer is exposed to moisture - the second gel-forming layer (120) has a swelling rate, which is higher than said first skin adhesive layer (110).

2. The adhesive wafer (100) according to claim 1, wherein said swelling rate is measured as according to the swelling speed test method A described in the specification.

3. The adhesive wafer (100) according to any one of the preceding claims, wherein said adhesive wafer (100) comprises opposing distal (101) and proximal (102) surfaces and a through-hole (103) from said distal surface (101) to said proximal surface (102) for accommodating a stoma.

4. The adhesive wafer (100) according to any one of the preceding claims, wherein the distal surface (101) of the adhesive wafer (100) comprises or consists of the second gelforming layer (120), and the proximal surface (102) of the adhesive wafer (100) comprises or consists of the first skin adhesive layer (110).

5. The adhesive wafer (100) according to any one of the preceding claims, wherein the second gel-forming layer has a swelling rate, when measured as according to the swelling speed test method described in the specification, which is at least two times greater than, preferably at least five times greater than, more preferably at least 10 times greater, than the swelling rate of said first skin adhesive layer.

6. The adhesive wafer (100) according to any one of the preceding claims, wherein the first skin adhesive layer (110), and the second gel-forming layer (120) are arranged adjacent each other, and preferably directly adjacent each other, in the adhesive wafer.

7. The adhesive wafer (100) according to any one of claims 1-6, wherein a film layer (105) is arranged between the first skin adhesive layer (110), and the second gel-forming layer (120), and / or on an external surface of the second gel-forming layer (120).

8. The adhesive wafer (100) according to any one of claims 1-7, wherein said film layer (105) comprises a plastically deformable film material.

9. The adhesive wafer (100) according to any one of claims 4-8, wherein a release liner (107) is arranged on the proximal surface (102) of the adhesive wafer (100).

10. The adhesive wafer (100) according to any one of the preceding claims, said adhesive wafer (100) further comprising a third non-adhesive water-swellable gel-forming layer (130), wherein - when the adhesive wafer is exposed to moisture - the third gel-forming layer (130) has a swelling rate, when measured as according to the swelling speed test method described in the specification, which is higher than the swelling rate of the second gelforming layer (120).

11. The adhesive wafer (100) according to claim 10, wherein the third gel-forming layer (130) is arranged between said first skin adhesive layer (110) and said second gel-forming layer (120); alternatively, wherein the second gel-forming layer (120) is arranged between the third gel-forming layer (130) and the first skin adhesive layer (110), preferably wherein the second gel-forming layer (120) is arranged between the third gel-forming layer (130) and the first skin adhesive layer (110).

12. The adhesive wafer (100) according to claim 10, wherein the second gel-forming layer (120) is located at least in a first region of said adhesive wafer (100) which extends radially from the stomal through-hole (103), wherein the third gel-forming layer (130) is located at least in a second region of said adhesive wafer (100), said first region and said second region being located concentrically on the first skin adhesive layer.

13. The adhesive wafer (100) according to any one of claims 10-12, wherein a film layer (105) is arranged between the first skin adhesive layer (110), and the third gel-forming layer (130), and / or between the first skin adhesive layer (110), and the third gel-forming layer (130).

14. The adhesive wafer (100) according to any one of claims 11-13, wherein said film layer (105) comprises a plastically deformable film material.

15. The adhesive wafer (100) according to any one of the preceding claims, wherein the second and / or the third gel-forming layers (120, 130) comprise a clay, such as a smectite clay, preferably bentonite or laponite, more preferably laponite.

16. The adhesive wafer (100) according to any one of claims 10-15, wherein the dimension of the second gel-forming layer (120) in a direction away from the stomal through-hole (103) is less than the dimension of the third gel-forming layer (130) in said direction.

17. The adhesive wafer (100) according to any one of the preceding claims, wherein each of said first skin adhesive layer (110), second gel-forming layer (120) and said third gelforming layer (130) has a circular through-hole, and preferably wherein each of the circular through-holes have the same diameter and wherein the inner surface of each circular through-hole in one layer is aligned with the inner surface of each circular through-hole in an adjacent layer.

18. The adhesive wafer (100) according to any one of claims 10-17, wherein a film layer (105) is arranged at at least one location selected from: between the first skin adhesive layer (110) and the second gel-forming layer (120), between the second adhesive layer (120) and the third gel-forming layer (130) and on an external surface of the third gel-forming layer (130).

19. The adhesive wafer (100) according to any one of claims 11-18, wherein said film layer (105) comprises a plastically deformable film material.

20. The adhesive wafer (100) according to any one of the preceding claims, further comprising a second skin-adhesive adhesive layer (140), arranged such that at least the second gel-forming layer (120), and preferably the third gel-forming layer (130), is / are located between the first skin-adhesive layer (110) and the second skin-adhesive adhesive layer (140).

21. The adhesive wafer (100) according to claim 20, wherein a release liner (107) is arranged on an external surface of the second skin-adhesive layer (140).

22. The adhesive wafer (100) according to any one of the preceding claims, wherein the second and / or the third gel-forming layers (220, 230) comprise a clay, such as a smectite clay, preferably montmorilonite, bentonite or laponite, more preferably laponite.

23. A mouldable protective seal (200) for placement between a user's skin and an adhesive wafer of an ostomy device, said protective seal (200) comprisinga first skin-adhesive seal layer (210), and a second non-adhesive, water-swellable gel-forming layer (220), optionally, a third non-adhesive water-swellable gel-forming layer (230), wherein said protective seal (200) comprises opposing distal (201) and proximal (202) surfaces and a through-hole (203) from said distal surface (201) to said proximal surface (202) for accommodating a stoma, wherein the proximal surface (202) of said protective seal (200) is comprised by the first skin adhesive layer (210), wherein said protective seal (200) is essentially ring-shaped; wherein - when the protective seal (200) is exposed to moisture - the second gelforming layer (220) has a swelling rate, which is higher than said first skin adhesive layer (210), and wherein - when the protective seal (200) is exposed to moisture - the third gelforming layer (230) (when present) has a swelling rate, when measured as according to the swelling speed test method described in the specification, which is higher than the swelling rate of the second gel-forming layer (220).

24. The mouldable protective seal (200) according to claim 23, wherein said swelling rate is measured as according to the swelling speed test method A described in the specification.

25. The protective seal (200) according to any one of claims 23-24, wherein the first adhesive seal layer (210), the second gel-forming layer (220) and the third gel-forming layer (230) are co-extensive in the plane of said protective seal (200).

26. The protective seal (200) according to any one of claims 23-25, further comprising a second adhesive layer (240), wherein the distal surface (201) of said protective seal (200) is comprised by the second adhesive layer (240).

27. The protective seal (200) according to any one of claims 23-26, wherein a film layer (205) is arranged between the first adhesive seal layer (210), and the second gel-forming layer (220), and / or on an external surface of the second gel-forming layer (220).

28. The protective seal (200) according to any one of claims 23-27, wherein said film layer (105) comprises a plastically deformable film material.

29. The protective seal (200) according to any one of claims 23-28, wherein a release liner (207) is arranged on an external surface of the first adhesive seal layer (210).

30. The protective seal (200) according to any one of claims 23-29, wherein a release liner (207) is arranged on an external surface of the second skin-adhesive layer (240).

31. The protective seal (200) according to any one of claims 23-30, wherein the second and / or the third gel-forming layers (220, 230) comprise a clay, such as a smectite clay, preferably montmorilonite, bentonite or laponite, more preferably laponite.

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