GB2626947A

GB2626947A - Ostomy appliance including a filter

Info

Publication number: GB2626947A
Application number: GB2301726.2A
Authority: GB
Inventors: Alexander Shirin; Apsey Henry; Hill Donald; Olonisakin Omotoke; Powner Iain
Original assignee: Salts Healthcare Ltd
Current assignee: Salts Healthcare Ltd
Priority date: 2023-02-07
Filing date: 2023-02-07
Publication date: 2024-08-14
Also published as: WO2024165845A1

Abstract

An ostomy appliance 10 including a filter 20, the filter including a substrate at least partially coated with a sorbent material, the sorbent material including a basic copper sulphate (e.g., brochantite, Cu4SO4(OH)6). The sorbent material may further include: a copper oxide (e.g., Cu(II) oxide, 5-25 %); nanowires (less than 50 nm width); and particles with an average specific surface area of 50-200 m2g-1. The filter may include a gas-permeable layer, and a gas and liquid-impermeable barrier layer, attached to the substrate. Also disclosed is an ostomy appliance including a filter with a substrate at least partially coated with a metal-containing sorbent material, wherein the sorbent material includes nanowires of less than 50 nm width. Also disclosed is a method for manufacturing an ostomy appliance including a filter, the method including drawing a sorbent material through a substrate by applying a pressure differential across the substrate; and attaching the substrate to an ostomy appliance.

Description

OSTOMY APPLIANCE INCLUDING A FILTER

FIELD

The present invention relates to an ostomy appliance including a filter.

BACKGROUND

It is known to provide in a wall of an ostomy appliance ('bag' or 'pouch' as they are commonly known in the art) an aperture to permit waste gases to escape from a waste collecting chamber of the ostomy appliance. This is necessary to prevent the bag expanding too much with gas and potentially from leaking or bursting whilst filled with waste. In some prior art ostomy appliances the aperture is covered by a filter, the purpose of which is to de-odorise the waste gases before they exit to atmosphere.

The effectiveness of the filter depends on the structure and composition of the filter. An ostomy appliance with a more effective filter is desired.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is an ostomy appliance including a filter, the filter including a substrate at least partially coated with a sorbent material, the sorbent material including a basic copper sulphate.

The basic copper sulphate may be brochantite.

The sorbent material may further include a copper oxide, optionally wherein the copper oxide may be copper(II) oxide.

The relative quantities of basic copper sulphate and copper oxide in the sorbent material may be in the range of about 75-95% basic copper sulphate and about 5-25% copper oxide.

The sorbent material may include nanowires.

The nanowires may have a length to width ratio of at least 10:1, optionally a length to width ratio of at least 20:1.

The width of the nanowires may be less than about 100 nm, optionally less than about 50 nm.

The sorbent material may include particles having an average specific surface area in the range of about 50-200 m2g-1, optionally in the range of about 50-125 m29-1.

The filter may further include a gas-permeable layer attached to the substrate.

25 30 35 The filter may further include a gas and liquid-impermeable barrier layer attached to the substrate.

The gas permeable layer may be attached to a first side of the substrate and the barrier layer may be attached to a second side of the substrate opposite the first side.

The filter may include a substrate at least partially coated with a metal-containing sorbent material, wherein the sorbent material includes nanowires having a width of less than 50 nm.

The nanowires may have an average specific surface area in the range of about 50-200 m29-1, optionally in the range of about 50-125 m29-1.

The sorbent material may include a basic copper sulphate, optionally brochantite.

The filter may be a resin-free filter. Alternatively, the filter may include a resin, for example, to enable bonding of the sorbent material and the substrate.

Also disclosed is a method for manufacturing an ostomy appliance including a filter, the method including: passing a sorbent material through a substrate by applying a pressure differential across the substrate to create a filter; and attaching the filter to an ostomy appliance.

The pressure differential may be applied by applying a partial vacuum to a first side of the substrate and applying the sorbent material to a second, opposing, side of the substrate.

The sorbent material may be provided as a sorbent material suspension.

The sorbent material may be suspended in an alcohol.

The sorbent material may further include copper(II) oxide.

BRIEF DESCRIPTION OF THE FIGURES

In order that the present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front view of a first embodiment of an ostomy appliance; Figure 2 is a side cross-sectional view of the ostomy appliance of figure 1; Figure 3 is a further side cross-sectional view of the ostomy appliance of figure 1; Figure 4 is a front view of a second embodiment of an ostomy appliance; Figure 5 is a side cross-sectional view of the ostomy appliance of figure 4; Figure 6 is a further side cross-sectional view of the ostomy appliance of figure 4; Figure 7 is a perspective view of an example of a multi-layer filter for use in the first and second embodiments of the ostomy appliance; Figures 8a-8d show x-ray diffraction (XRD) data for four sorbent material samples; Figure 9 shows nitrogen adsorption isotherms for the four sorbent material samples; Figure 10 shows transmission electron microscopy images of the four sorbent material samples; Figures 11a-d show hydrogen sulphide breakthrough data for polyurethane filters coated with the four sorbent material samples; and Figure 12 shows hydrogen sulphide breakthrough data for two polyurethane filters impregnated with a commercially-available sorbent material.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring firstly to figures 1 to 3 these show a first embodiment of an ostomy appliance 10. The general construction of the ostomy appliance 10 is similar to those well known in the art and may, therefore, include first 11 and second 12 walls which are connected to each other at or near their peripheries, for example by welding or using an adhesive. The ostomy appliance 10 shown could be a drainable appliance, meaning that its contents could be emptied through an outlet (50, shown in broken lines) between the first 11 and second 12 walls.

The first wall 11 may have a stoma-receiving opening 13 and may be connected to a generally circular connection member 14 in the form of a flange for adhering the appliance 10 to a user around their stoma. The connection member 14 could be any appropriate shape, however.

The ostomy appliance 10 may define at least one chamber therein. A waste collecting chamber 30 may be provided, which may communicate with the stoma-receiving opening 13 and, if the ostomy appliance is a drainable appliance, at its lower end with an outlet (50). The waste collecting chamber may be defined between the first 11 and second 12 walls and may be provided as the primary chamber for collecting a user's waste, which enters the chamber through the opening 13 in the first wall 11. More chambers (not shown) may be provided within the ostomy appliance, for example in order to create a tortuous path for the waste gas to exit the appliance and/or to allow fluid in a further chamber to pass into the waste collecting chamber 30 via a non-return valve.

An aperture 15 may be provided in the second wall 12 to permit waste gas within the ostomy appliance 10 to exit the appliance. The aperture 15 may be provided above the stoma-receiving opening 13 in use to reduce the likelihood of waste collected in the waste collecting chamber 30 from getting near to and/or contaminating the aperture 15. The aperture 15 may be circular in shape but can be formed in a number of different shapes. The aperture 15 may include a plurality of apertures, for example in the form of perforations provided in the second wall 12. Although the aperture 15 is shown in figure 1 as being provided in the second wall 12, it may instead be provided in the first wall 11. Alternatively, apertures may be provided on both the first 11 and second 12 walls.

The disclosed technology includes an ostomy appliance filter 20.

The filter 20 may include a substrate, which may be at least partially coated with a sorbent material. The filter 20 may, therefore, include a de-odorising layer 22, and the de-odorising layer 22 may include the substrate which, as described, may be at least partially coated with the sorbent material.

The sorbent material may include a cupric sulphate, which may be a basic cupric sulphate. The cupric sulphate may be brochantite. Brochantite has the chemical formula Cu4SO4(OH)6. The substrate may, therefore, be at least partially coated with a cupric sulphate, which may be a basic cupric sulphate. The terms "copper sulphate" and "cupric sulphate" may be used interchangeably.

The sorbent material may, therefore, include a copper sulphate, which may be a basic copper sulphate. The substrate may be at least partially coated with brochantite.

The sorbent material may include a copper oxide. The copper oxide may be copper(II) oxide, also known as cupric oxide. Copper(II) oxide has the chemical formula CuO. The substrate may, therefore, be at least partially coated with a copper oxide. The substrate may be at least partially coated with copper(II) oxide.

The sorbent material may include both a cupric sulphate (optionally a basic cupric sulphate) and a copper oxide, such as brochantite and copper(II) oxide. The substrate may, therefore, be at least partially coated with a combined coating including the cupric sulphate and the copper oxide. The substrate may, in particular, be at least partially coated with a combined coating including brochantite and copper (II) oxide. In some versions separate coatings of the cupric sulphate and the copper oxide may be applied to the substrate, and the substrate may therefore be at least partially coated with a first coating including the cupric sulphate and at least partially coated with a second coating including the copper oxide. The first and second coatings may, therefore, be separate coatings, which may be applied successively and/or to different parts of the substrate, for example.

The sorbent material may, as described, include both a cupric sulphate, optionally a basic cupric sulphate, such as brochantite, and copper oxide (e.g. copper(II) oxide). The relative quantities of cupric sulphate and copper oxide may, therefore, be expressed using percentages, where 100% cupric sulphate indicates a sorbent material that includes no copper oxide, 50% cupric sulphate and 50% copper oxide indicates a sorbent material that includes equal amounts of cupric sulphate and copper oxide, and 100% copper oxide indicates a sorbent material that includes no cupric sulphate. The sorbent material may include about 10-100% cupric sulphate (and therefore about 90-0% copper oxide), about 20-100% cupric sulphate (and therefore about 80-0% copper oxide), about 30-100% cupric sulphate (and therefore about 70-0% copper oxide), about 40-100% cupric sulphate (and therefore about 60-0% copper oxide), about 50-100% cupric sulphate (and therefore about 50-0% copper oxide), about 60-100% cupric sulphate (and therefore about 40-0% copper oxide), about 70100% cupric sulphate (and therefore about 30-0% copper oxide), about 80-100% cupric sulphate (and therefore about 20-0% copper oxide), about 40-98% cupric sulphate (and therefore about 602% copper oxide), about 75-95% cupric sulphate (and therefore about 25-5% copper oxide), about 70-95% cupric sulphate (and therefore about 30-5% copper oxide), about 75-90% cupric sulphate (and therefore about 25-10% copper oxide), or about 80-85% cupric sulphate (and therefore about 20-15% copper oxide). The relative amounts of cupric sulphate and copper oxide may be determined using Rietveld refinement (which may be performed on data obtained from x-ray powder diffraction). The relative quantities may be provided as % w/w, i.e. as a percentage weight per weight.

The sorbent material may, as described, include both a cupric sulphate such as brochantite and copper oxide (e.g. copper(II) oxide). The relative quantities of brochantite and copper oxide may, therefore, be expressed using percentages, where 100% brochantite indicates a sorbent material that includes no copper oxide, 50% brochantite and 50% copper oxide indicates a sorbent material that includes equal amounts of brochantite and copper oxide, and 100% copper oxide indicates a sorbent material that includes no brochantite. The sorbent material may include about 10-100% brochantite (and therefore about 90-0% copper oxide), about 20-100% brochantite (and therefore about 80-0% copper oxide), about 30-100% brochantite (and therefore about 70-0% copper oxide), about 40-100% brochantite (and therefore about 60-0% copper oxide), about 50-100% brochantite (and therefore about 50-0% copper oxide), about 60-100% brochantite (and therefore about 40-0% copper oxide), about 70-100% brochantite (and therefore about 30-0% copper oxide), about 80100% brochantite (and therefore about 20-0% copper oxide), about 40-98% brochantite (and therefore about 60-2% copper oxide), about 75-95% brochantite (and therefore about 25-5% copper oxide), about 70-95% brochantite (and therefore about 30-5% copper oxide), about 75-90% brochantite (and therefore about 25-10% copper oxide), or about 80-85% brochantite (and therefore about 20-15% copper oxide). The relative amounts of brochantite and copper oxide may be determined using Rietveld refinement (which may be performed on data obtained from x-ray powder diffraction). The relative quantities may be provided as % w/w, i.e. as a percentage weight per weight.

The sorbent material may include particles, such as rod-shaped or wire-like particles, which may be nanowires. The particles may have an associated length and width (or diameter), with the length measured along the longitudinal axis of the particle and the width (or diameter) measured along a corresponding transverse axis. The particles may have an average (mean or median) length to width ratio of at least 2:1, at least 5:1, at least 10:1, at least 15:1, at least 20:1, or at least 25:1. The average (mean or median) width may be less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, less than about 90 nm, less than about 80 nm, less than about 70 nm, less than about 60 nm, less than about nm, less than about 40 nm, less than about 30 nm, less than about 20 nm, or less than about 10 nm. The average width may, in particular, be less than about 50 nm, and some particles may be less than 10 nm wide. The average (mean or median) length may be at least about 100 nm, at least about 150 nm, at least about 200 nm, at least about 300 nm, at least about 400 nm, at least about 500 nm, at least about 600 nm, at least about 700 nm, at least about 800 nm, at least about 900 nm, at least about one micron, or at least about 2 microns, or between 1 and 20 microns, or between 1 and 10 microns, or between 1 and 5 microns.

The sorbent material may include particles (which may be nanowires) having a length to width ratio of at least 2:1, at least 5:1, at least 10:1, at least 15:1, at least 20:1, or at least 25:1. The sorbent material may include particles (which may be nanowires) having a width of less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, less than about 90 nm, less than about 80 nm, less than about 70 nm, less than about 60 nm, less than about 50 nm, less than about 40 nm, less than about 30 nm, less than about 20 nm, or less than about 10 nm. The width may, in particular, be less than about 50 nm, and may be less than 10 nm. The sorbent material may include particles (which may be nanowires) having a length of at least about 100 nm, at least about 150 nm, at least about 200 nm, at least about 300 nm, at least about 400 nm, at least about 500 nm, at least about 600 nm, at least about 700 nm, at least about 800 nm, at least about 900 nm, at least about one micron, or at least about 2 microns, or between 1 and 20 microns, or between 1 and 10 microns, or between 1 and 5 microns. The sorbent material may, in particular, include nanowires having a width of less than 50 nm, optionally less than 10 nm.

The sorbent material (e.g. the particles of sorbent material, which may include brochantite and may further include copper(II) oxide) may have a specific surface area in the range of about 10-150 m2g1, about 40-150 m29-I, about 60-150 m2g-1, about 60-125 m2g-1, about 60-100 m29-1, about 50-80 m29-1, about 55-75 m29-1, about 60-80 m2g-1, about 65-80 m2g-1, about 65-75 m291-1, or about 66-72 m2g-1.

The sorbent material may be synthesised using a hydroxide ion source, a copper ion source, and a sulphate ion source. The sorbent material may be synthesised by combining the hydroxide ion source, the copper ion source, and the sulphate ion source in aqueous solution. One source may provide more than one of the ions, for example one source may provide both the copper ions and the sulphate ions. The sorbent material may be synthesised using Na0H(ac7 and CuSO4(aq).

In a first example of the sorbent material synthesis, 241 ml of a 0.5 M NaOH(aq) solution was added dropwise to 75 ml of a 1.0 M CuSO4(aq) solution over a period of approximately five and a half hours.

The reaction mixture was stirred continuously over this period. During the addition, the colour of the mixture was observed to change from light blue to turquoise, and then finally to black as solids were formed within the liquid. The mixture was then allowed to stir overnight. Following this, the mixture was centrifuged at 3800 rpm for one hour to collect the solid. The recovered solid was re-suspended in water and then centrifuged once again under the same conditions. This process was repeated two further times. The slurry was dried overnight at 60 °C. The mass of the recovered solid was 5.87 g. The product of this synthesis is referred to herein as sample one.

In a second example of the sorbent material synthesis, 218 ml of a 0.5 M NaOH(aq) solution was added dropwise to 75 ml of a 1.0 M CuSO4,,N) solution over a period of approximately five hours.

The reaction mixture was stirred continuously over this period. During the addition, the colour of the mixture was observed to change from light blue to turquoise, and then finally to black as solids were formed within the liquid. The mixture was then allowed to stir overnight. Following this, the mixture was centrifuged at 3800 rpm for one hour to collect the solid. The recovered solid was re-suspended in water and then centrifuged once again under the same conditions. This process was repeated two further times. The slurry was dried overnight at 60 °C. The mass of the recovered solid was 6.94 g. The product of this synthesis is referred to herein as sample two.

In a third example of the sorbent material synthesis, 208 ml of a 0.5 M NaOH(aq) solution was added dropwise to 75 ml of a 1.0 M CuSO4(aq) solution over a period of approximately four hours. The reaction mixture was stirred continuously over this period. During the addition, the colour of the mixture was observed to change from light blue to turquoise, and then finally to black as solids were formed within the liquid. The mixture was then allowed to stir overnight. Following this, the mixture was centrifuged at 3800 rpm for one hour to collect the solid. The recovered solid was re-suspended in water and then centrifuged once again under the same conditions. This process was repeated two further times. The slurry was dried overnight at 60 °C. The mass of the recovered solid was 6.95 g. The product of this synthesis is referred to herein as sample three.

In a fourth example of the sorbent material synthesis, 255 ml of a 0.5 M NaOH(aq) solution was added dropwise to 75 ml of a 1.0 M CuSO4(aq) solution over a period of approximately six hours. The reaction mixture was stirred continuously over this period. During the addition, the colour of the mixture was observed to change from light blue to turquoise, and then finally to black as solids were formed within the liquid. The mixture was then allowed to stir for three days. Following this, the mixture was centrifuged at 3800 rpm for one hour to collect the solid. The recovered solid was re-suspended in water and then centrifuged once again under the same conditions. This process was repeated two further times using water and then ethanol. The slurry was dried overnight at 100 °C. The mass of the recovered solid was 7.76 g. The product of this synthesis is referred to herein as sample four.

The substrate may include a polymer, and may include a polymer foam, for example a polymer foam disc. The substrate may include polyurethane and may, therefore, be a polyurethane substrate. The substrate may include a polyurethane foam, for example, and may be formed as a polyurethane foam disc. The substrate may additionally or alternatively include other polymers and/or polymer foams, such as ethylene-vinyl acetate, low-density polyethylene, polychloroprene, polyimide, polypropylene, etc. The substrate may include a non-woven polyester fabric and may, therefore, be a non-woven polyester fabric substrate. The substrate may additionally or alternatively include cotton wool, non-woven fabric, woven fabric, and/or paper pulp. The substrate may, therefore, be a cotton wool, nonwoven fabric, woven fabric, and/or paper pulp substrate. The substrate may include any combination of the above.

The substrate may be coated with sorbent material by droplet coating.

The substrate may be coated (or at least partially coated) with the sorbent material by applying a pressure differential across the substrate. The substrate may have first and second sides, which may oppose each other. A pressure differential may be applied across the opposing sides of the substrate. For example, a vacuum (or partial vacuum) may be applied to the first side of the substrate and the sorbent material may be applied to the second side of the substrate. The sorbent material may, therefore, be drawn through the substrate by the pressure differential (e.g. the vacuum, or partial vacuum). In other words, the sorbent material may be sucked through the substrate.

Alternatively, the pressure differential may be created by increasing the pressure on one side of the substrate (e.g. by increasing the pressure above atmospheric pressure). For example, an increased pressure may be applied to the second side of the substrate and the sorbent material may be applied to the second side of the substrate. In other words, the sorbent material may be blown through the substrate. The pressure differential may be created by both lowering the pressure on one side of the substrate and increasing the pressure on the other side of the substrate. For example, the first side of the substrate may be subjected to a reduced pressure (e.g. by application of an at least partial vacuum) and the second side of the substrate may be subjected to an increased pressure. The sorbent material may be applied to the second side of the substrate. In other words, therefore, the sorbent material may be both sucked and blown through the substrate. The application of both reduced and increased pressure to opposite sides of the substrate may increase throughput of sorbent material through the substrate.

The substrate may be coated (or at least partially coated) with the sorbent material using a vacuum-assisted coating technique. For example, the substrate may have first and second sides, which may oppose each other. A vacuum may be applied to the first side of the substrate and the sorbent material may be applied to the second side of the substrate. The sorbent material may, therefore, be drawn through the substrate by the vacuum. It will be appreciated that the vacuum applied to the substrate may be a partial vacuum and, therefore, the coating may generally be performed using a pressure below atmospheric pressure to draw the sorbent material through the substrate. In other words, coating the substrate may include sucking the sorbent material through the substrate.

The substrate may be coated with a sorbent material suspension. The sorbent material may be suspended in an alcohol, for example, such as isopropanol. The substrate may then be dried once coated with the sorbent material suspension. The substrate may be dried by applying a gas flow to the substrate (e.g. air, for example provided by a fan). An inert gas may be used to dry the substrate, such as nitrogen.

The coating may be performed without using resin. The filter 20 may, therefore, not include resin. In other words, the filter 20 may be a resin-free filter. This may provide improved adsorption characteristics.

In some cases, the coating and substrate may be bonded using a resin, such as a phenolic resin.

Other coating techniques, such as dip coating, may be used.

In an example coating technique, 1.00 g of sorbent material was dispersed in 15 ml of isopropanol and the resulting suspension stirred for two days at room temperature. Polyurethane discs (25 mm diameter, 2.5 mm thickness) were placed in a buchner funnel and a flask attached underneath, which was connected to a vacuum pump using rubber hosing. The pump was then turned on to apply a vacuum to the polyurethane discs and then the sorbent-containing suspension was pipetted onto the polyurethane discs. The pieces were dried until they reached constant mass using a low velocity stream of air from a hair dryer. This coating technique was used to coat polyurethane discs with the sorbent materials of samples one to four, to produce a de-odorising layer for the filter 20. In the example, each sample was coated on a separate polyurethane disc.

The filter 20 may be a multi-layered filter as shown in more detail in figure 7. The multi-layered filter 20 may include a gas permeable, optionally hydrophobic, layer 21, the de-odorising layer 22 and/or a gas and liquid-impermeable barrier layer 23. The gas permeable layer 21 may form an outer layer of the filter 20. The barrier layer 23 may form an outer layer of the filter 20. The multi-layered filter may therefore be arranged with the de-odorising layer 22 between the gas permeable layer 21 and the barrier layer 23. The gas permeable layer 21 may, therefore, oppose the barrier layer 23. The gas permeable layer 21 may be configured to face the ostomy appliance 10 and the barrier layer 23 may be configured to face an external environment. In use, therefore, the filter 20 may be attached to the ostomy appliance 10 with the gas permeable layer 21 facing the ostomy appliance 10.

The gas permeable layer 21 may include polytetrafluoroethylene (PTFE). The hydrophobic nature of PTFE ensures that water molecules are repelled from its surface, meaning that any interaction between the surface of the PTFE layer and water molecules is substantially resisted, and thus, the PTFE layer is waterproof.

The de-odorising layer 22 may receive waste gas travelling through the gas permeable layer 21 and de-odorise the waste gas such that it is ready to exit the de-odorising layer 22 into atmosphere.

The barrier layer 23 may include CryovacTM material (e.g. CryovacTM MF540) that does not allow gas or liquid to pass through its surface. The barrier layer 23 may be positioned directly adjacent the deodorising layer 22 such that it lies on an opposite side of the de-odorising layer 22 to the gas permeable layer 21. The barrier layer 23 partially protects the de-odorising layer 22 from getting damp and/or clogged by moisture that is provided externally of the ostomy appliance 10, for example when a user is showering.

The filter 20 may be provided externally of the ostomy appliance 10 as shown in figures 1 and 2. More specifically the filter 20 may be attached to an exterior surface of the second wall 12. The filter may be attached to the second wall 12 adjacent the aperture 15 so that the aperture is fully covered by the filter 20. The aperture 15 may be a smaller diameter than the diameter of the filter 20 (see e.g. figure 1). Therefore, any waste gases that exit the ostomy appliance 10 through the aperture 15 must pass through the filter 20 in order to pass to atmosphere. The filter 20 may be attached by an adhesive connection, or any appropriate way, for example heat welding.

The gas permeable layer 21 of the multi-layered filter 20 may be positioned directly adjacent the second wall 12, for example to directly and completely cover the aperture 15 provided in the second wall 12. The gas permeable layer 21 may have a first side and second side and the first side may be connected directly to the second wall 12. This connection may hold the multi-layer filter relative to the wall 12. The gas permeable layer 21 may be connected directly to the second wall 12 by an adhesive, e.g. a holt melt adhesive or double-sided tape. Therefore, the gas permeable layer 21 may be in direct fluid communication with the waste collecting chamber 30 such that any waste gas exiting the ostomy appliance 10 must travel through the gas permeable layer 21 first. The advantage of providing the gas permeable layer 21 directly adjacent the aperture 15, and thus facing inwards towards the interior of the appliance 10, is that no liquid waste collected in the waste collecting chamber 30 can pass through the gas permeable layer 21 and into contact with the other layers of the multi-layered filter 20. This reduces the risk of the filter, in particular the de-odorising layer 22, from getting damp and/or clogged. A damp and/or clogged filter can lead to ballooning of the ostomy appliance which can significantly reduce the effectiveness of the filter and the appliance. This will inevitably lead to the user having to replace the flawed ostomy appliance.

Further to this, the multi-layered filter 20 may be positioned on an external surface of the second wall 12 such that the de-odorising layer 22 and barrier layer 23 cannot come into direct contact with the waste collected in the waste collecting chamber 30 which significantly reduces the risk of the filter 20 becoming damp and/or clogged. Further to this, providing the filter 20 externally of the ostomy appliance 10, e.g. external of the wall or walls which form the waste collecting chamber, allows for an easier and thus more cost effective manufacturing process as there is no need to place the filter carefully between layers of the ostomy appliance before they are connected together. Instead, the filter 20 can, if desired, be attached to the ostomy appliance once the walls of the appliance have been sealed together around its peripheries.

Referring to figure 3, arrows 24, 25 show a possible directional flow path taken by waste gas when exiting the waste collecting chamber 30 through the filter 20. The waste gas may travel through the aperture 15 and into the gas permeable layer 21 (when present) in a direction substantially perpendicular to the second wall 12. Thereafter the waste gas may travel through the gas permeable layer 21 and into the de-odorising layer 22 in a direction substantially perpendicular to the second wall 12. Finally, the waste gas may travel through and exit the de-odorising layer 22 in a direction substantially parallel to the second wall 12, i.e. radially away from an axis of the filter 20. The positioning of the barrier layer 23 directly adjacent the de-odorising layer 22 ensures that all gas entering the filter 20 passes through the de-odorising layer 22 in a direction substantially parallel to the second wall 12. The barrier layer 23 may, therefore, force waste gases to travel along a longer route through the filter 20 compared to a filter not including the barrier layer 23, which may provide improved filtering of waste gases.

In an example, filters, containing the polyurethane discs coated with samples one to four as described previously, were prepared by first attaching a 25 mm diameter PTFE (e.g. Gore-Tex®) disc over a 12 mm diameter hole present in an ostomy appliance film (a Nexcel® MF film was used in this example) using a narrow layer of adhesive applied to the edge of the PTFE disc. The coated polyurethane was then secured onto the PTFE disc using the adhesive in the same manner. Finally, a layer of impermeable CryovacTM (e.g. MF540) was placed on the top of the polyurethane and secured using adhesive. In this example, the gas permeable layer 21 is provided by the PTFE disc, the de-odorising layer 22 is provided by the coated polyurethane disc, and the barrier layer 23 is provided by the CryovacTM layer. Four separate filters were therefore produced using each of samples one to four.

Figures 8a to 8d show x-ray diffraction (XRD) data for samples one to four described previously. XRD was carried out using a Bruker D8 Discover diffractometer equipped with a non-monochromatic Cu-K. x-ray source. Data were recorded over a 20 range of 10-70 ° using a step time of 0.5 s and an increment of 0.02 ° per step. Scans were analysed using the instrument's Diffrac.EVA software. Percentages of the CuO and Cu4(OH)6SO4 present in the samples were calculated using Rietveld refinement and presented in table 1. XRD scans of samples one to four are shown in figures 8a-8d, in which figure 8a shows XRD data for sample one, figure 8b shows XRD data for sample two, figure 8c shows XRD data for sample three, and figure 8d shows XRD data for sample four. In figures 8a- 8d a corresponds to Cu4(OH)6SO4 and p corresponds to CuO.

Relative percentages (w/w) of copper(II) oxide (CuO) and brochantite (Cu4(OH)6SO4) in the sample sorbents were calculated using Rietveld refinement on the XRD data, and are summarised in table 1 below.

Material Percentage of CuO Percentage of Cu4(OH)6SO4 (w/w) (w/w) Sample 1 57.40 42.6 Sample 2 15.50 84.50 Sample 3 3.65 96.35 Sample 4 18.79 81.21 Table 1: relative percentages of copper(1l) oxide and brochantite in samples one to four.

Figure 9 shows nitrogen adsorption isotherms for sample one (diamonds), sample two (circles), sample three (squares), and sample four (triangles).

N2 sorption analysis at 77 K was performed on a Quantochrome Instruments Nova 2000 Multi-Station Nitrogen Adsorption Analyser. Samples weighing approximately 300-500 mg were degassed under vacuum for at least 2 hours ahead of analysis. The BET equation was fitted in the 0.201-0.281 P/Po range. Nitrogen adsorption isotherms for samples one to four and specific surface areas are shown in Fig. 9 and Table 2. As shown in Fig. 9, sample three consistently had the highest adsorbed volume, followed by sample two, then sample four, with sample one consistently having the lowest adsorbed volume.

Material Specific surface area (m2g-1) Sample 1 56.5 Sample 2 71.4 Sample 3 78.3 Sample 4 66.3 Table 2: Specific surface areas of samples one to four calculated using the BET measurement.

As shown in Table 2, sample three had the highest specific surface area, followed by sample two, sample four, and sample one had the lowest specific surface area. This correlates with the relative percentage of brochantite present in each sample (see Table 1).

Figure 10 shows transmission electron microscopy images of samples one to four, in which images a-d are based on sample one, images e-h are based on sample two, images i-I are based on sample three, and images m-p are based on sample four. As shown in the images, the sorbent material includes particles, and more specifically includes nanowires. The dimensions of the particles or nanowires can vary, with some particles or nanowires having a width below 10 nm and a length over 200 nm. Such particles or nanowires therefore have a length to width ratio of above 20:1.

H2S breakthrough experiments were performed on filters including samples one to four as a sorbent material. Each filter included a different level of sorbent loading of the respective sample material.

A mixture of H2S (25 ppm), CH4 (20 %) and N2 (79.9975 %) was allowed to flow through the filters at a rate of 1.2 Lmin-1. Breakthrough was recorded when the concentration of H2S being detected was 2.0 ppm. Breakthrough times for the filters are shown in Table 3 and Figures 11a-d. Figure 11a shows H25 breakthrough curves for polyurethane coated with material from sample one, figure 11b shows H25 breakthrough curves for polyurethane coated with material from sample two, figure 11c shows H2S breakthrough curves for polyurethane coated with material from sample three, and figure 11d shows H25 breakthrough curves for polyurethane coated with material from sample four. In each case, the breakthrough curve illustrated using triangles corresponds to the lowest sorbent loading shown in Table 3 for that filter. The breakthrough curve illustrated using squares corresponds to the second-lowest sorbent loading, the circles correspond to the third-lowest sorbent loading, and the diamonds correspond the fourth-lowest sorbent loading (not present in the case of Fig. 11d as there were only three filters tested).

Sample 1 filter Sample 2 filter Sample 3 filter Sample 4 filter Sorbent H2S Sorbent H2S Sorbent H2S Sorbent H2S loading/ breakthrough loading/ breakthrough loading/ breakthrough loading/ breakthrough mg time/ minutes mg time/ minutes mg time! minutes mg time! minutes 129 95 110 157 116 118 83 114 67 100 151 79 72 53 41 51 22 73 109 50 25 20 7 23 9 27 16 44 15 Table 3: H2S breakthrough times for filters including samples one to four.

As shown in Table 3, the longest breakthrough times were observed for sample two, followed by sample four, then sample three and finally sample one. The data shows that all of the sorbent materials filter H2S, with samples two and four being the most effective. These samples included 84.50% brochantite to 15.50% copper(II) oxide and 81.21% brochantite to 18.79% copper(II) oxide, respectively. This suggests a filter including a mixture of both brochantite and copper(II) oxide may be particularly effective, for example with a relative percentage of about 75-95% brochantite to about 25-5% copper(II) oxide, or about 80-85% brochantite to about 20-15% copper(II) oxide. Longer breakthrough times are observed for higher levels of sorbent loading. The filter 20 may, therefore, include at least 20 mg of sorbent material, at least 50 mg of sorbent material, at least 80 mg of sorbent material, at least 100 mg of sorbent material, at least 120 mg of sorbent material, at least mg of sorbent material, at least 300 mg of sorbent material, at least 400 mg of sorbent material, at least 500 mg of sorbent material, at least 600 mg of sorbent material, at least 700 mg of sorbent material, at least 800 mg of sorbent material, at least 900 mg of sorbent material, or at least 1000 mg of sorbent material. The filter 20 may include about 20-500 mg of sorbent material, about 20- 400 mg of sorbent material, about 20-300 mg of sorbent material, about 20-200 mg of sorbent material, about 20-150 mg of sorbent material, about 50-150 mg of sorbent material, or about 50100 mg of sorbent material.

Breakthrough times for filters containing a carbon sorbent subjected to the same breakthrough experiment are shown in Table 4 and Figure 12. As shown, the sorbents disclosed herein outperformed or at least matched the performance of existing commercial sorbents, particularly at sorbent loading levels of about 50 mg or above.

Commercial filter example H2S breakthrough time/ minutes 1 25 2 27 3 30 4 30 Table 4: H2S breakthrough times through filters containing polyurethane impregnated with the commercial sorbent.

Figures 4 to 6 show a second embodiment of an ostomy appliance 110. Features which are in common with the first embodiment 10 have been given the same reference numeral with the addition of 100. Those features will not be discussed again here. The filter 120 is, therefore, as described regarding the filter 20.

Referring to the second embodiment the main difference is the size of the aperture 115 in relation to the filter 120. Instead of the aperture 115 being significantly smaller in diameter than the filter 120, the aperture 115 is substantially the same diameter as the filter 120. This provides for an increased area through which the waste gas can exit the ostomy appliance through the aperture 115 and into and through the gas permeable layer 121 and further reduces the risk of the aperture 115 becoming completely blocked with waste. The flow through the aperture 115 and filter 120 is substantially the same as that of the first embodiment, as shown by arrows 124, 125.

When used in this specification and claims, the terms "comprise" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The invention may also broadly consist in the parts, elements, steps, examples and/or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and/or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.

Claims

CLAIMS1. An ostomy appliance including a filter, the filter including a substrate at least partially coated with a sorbent material, the sorbent material including a basic copper sulphate.
2. An ostomy appliance according to claim 1, wherein the basic copper sulphate is brochantite.
3. An ostomy appliance according to claim 1 or 2, wherein the sorbent material further includes a copper oxide, optionally wherein the copper oxide is copper(II) oxide.
4. An ostomy appliance according to claim 2 or 3, wherein the relative quantities of basic copper sulphate and copper oxide in the sorbent material are in the range of about 75-95% basic copper sulphate and about 5-25% copper oxide.
5. An ostomy appliance according to any preceding claim, wherein the sorbent material includes nanowires.
6. An ostomy appliance according to claim 5, wherein the nanowires have a length to width ratio of at least 10:1, optionally a length to width ratio of at least 20:1.
7. An ostomy appliance according to claim 5 or 6, wherein the width of the nanowires is less than about 100 nm, optionally less than about 50 nm.
8. An ostomy appliance according to any preceding claim, wherein the sorbent material includes particles having an average specific surface area in the range of about 50-200 m2g-1, optionally in the range of about 50-125 m2g-1.
9. An ostomy appliance according to any preceding claim, wherein the filter further includes a gas-permeable layer attached to the substrate.
10. An ostomy appliance according to any preceding claim, wherein the filter further includes a gas and liquid-impermeable barrier layer attached to the substrate.
11. An ostomy appliance according to claim 10 when dependent on claim 9, wherein the gas permeable layer is attached to a first side of the substrate and the barrier layer is attached to a second side of the substrate opposite the first side.
12. An ostomy appliance including a filter, the filter including a substrate at least partially coated with a metal-containing sorbent material, wherein the sorbent material includes nanowires having a width of less than 50 nm.
13. An ostomy appliance according to claim 12, wherein the nanowires have a length to width ratio of at least 10:1, optionally a length to width ratio of at least 20:1.
14. An ostomy appliance according to claim 12 or 13, wherein the nanowires have an average specific surface area in the range of about 50-200 m2g-I, optionally in the range of about 50-125 m2g-1.
15. An ostomy appliance according to any of claims 12-14, wherein the sorbent material includes a basic copper sulphate, optionally brochantite.
16. An ostomy appliance according to any preceding claim, wherein the filter is a resin-free filter.
17. A method for manufacturing an ostomy appliance including a filter, the method including: passing a sorbent material through a substrate by applying a pressure differential across the substrate to create a filter; and attaching the filter to an ostomy appliance.
18. A method according to claim 17, wherein the pressure differential is applied by applying a partial vacuum to a first side of the substrate and applying the sorbent material to a second, opposing, side of the substrate.
19. A method according to any of claims 17-18, wherein the sorbent material is provided as a sorbent material suspension.
20. A method according to claim 19, wherein the sorbent material is suspended in an alcohol.
21. A method according to any of claims 17-20, wherein the sorbent material includes a basic copper sulphate, optionally brochantite.
22. A method according to claim 21, wherein the sorbent material further includes copper(II) oxide.