GB2640554A

GB2640554A - Absorbent pad for a wound dressing

Info

Publication number: GB2640554A
Application number: GB2405765.5A
Authority: GB
Inventors: Lee Bryony; Stephens Sally; Sandu Simran; Till Robbie
Original assignee: Medtrade Products Ltd
Current assignee: Medtrade Products Ltd
Priority date: 2024-04-24
Filing date: 2024-04-24
Publication date: 2025-10-29
Also published as: WO2025224452A1; GB202405765D0; GB2640554A8

Abstract

An absorbent pad for a wound dressing comprising a central region 3 and at least one distal region 4a 4b, wherein the central region comprises a first fenestration pattern 5a 5b comprising at least one fenestration, and wherein the at least one distal region comprises a second different fenestration pattern 7a 7b comprising at least one fenestration. The first pattern may be an open shape of cuts – e.g. part of a hexagon with four sides, wherein the second pattern may be five sides of a hexagon. Either pattern may be a linear arrangement of fenestrations. Each fenestration may be joined to another by a cut, or they may be discrete. The first pattern may have various lines of symmetry about axes of the pad. The present invention also relates to a method of manufacturing the absorbent pad and a wound dressing comprising an absorbent pad as described above.

Description

Absorbent Pad for a Wound Dressing Technical Field of the Invention The present invention relates to an absorbent pad for a wound dressing. In particular, the invention relates to an absorbent pad comprising a central region and at least one distal region, the central region having a first fenestration pattern and the distal region having a second fenestration pattern.

Background to the Invention

Absorbent pads are commonly used in the wound care field as a key feature in wound dressings. Due to their absorbent properties, absorbent pads are capable of removing any excess exudate from a wound site (e.g. blood, plasma etc.) by absorbing the excess exudate and either retaining the exudate within their structure or wicking the exudate away to other parts of the wound dressing or the surrounding environment.

However, often the components that make up such absorbent pads are rigid and limit the overall extensibility, flexibility and conformability of the wound dressing. This is a significant drawback for wound dressings that require a high degree of flexibility, extensibility and conformability; such as wound dressings for application to anatomical areas requiring a high degree of movement or anatomical areas that are difficult to dress (for example, joints such as hips, knees, elbows, feet, or amputation sites). Furthermore, due to their rigidity, following application of the wound dressing to the patient, the absorbent pad may prematurely detach from the wound site or the surrounding area of skin as the absorbent pad is unable to conform to the patient' s bodily movements. This results in the wound dressing requiring more frequent changing, which increases the time burden placed on clinicians, as well as increasing material costs associated with treatment and increases clinical waste.

Various design approaches have been considered by wound dressing manufacturers in an attempt to overcome this problem. One approach is to include a repeating pattern of cuts in the absorbent pads of wound dressings. Such patterns of cuts are known to improve the flexibility and extensibility of a wound dressing, and the higher the number of cuts in the absorbent pad, the more flexible and extensible the wound dressing is. This is particularly desirable for wound dressings that are designed for application to anatomical areas that are difficult to dress, or anatomical areas requiring a high degree of movement. However, providing a higher number of cuts may reduce the structural integrity of the absorbent pad, reduce the ability of the dressing to recover after extension, reduce the wicking ability of the pads and/or increase the moisture vapour transmission rate of the dressing which may lead to drying out of the wound thereby negatively affecting wound healing. Thus, these drawbacks may counteract the benefits imparted by increasing the number of cuts in the absorbent pad.

Therefore, it is an aim of embodiments of the present invention to provide an absorbent pad for a wound dressing with improved flexibility, conformability and extensibility that is effective for application to anatomical areas that are difficult to dress or anatomical areas having a high degree of movement, whilst maintaining the structural integrity of the absorbent pad. It is also an aim of the present invention that when the absorbent pad is applied the patient, bodily movement does not significantly distort the visual appearance of the absorbent pad.

It is a further aim of embodiments of the present invention to provide an absorbent pad for a wound dressing that is effective at absorbing wound exudate and/or stemming blood flow at a wound site.

It is a further aim of embodiments of the present invention to overcome or mitigate at least one problem of the prior art, whether expressly described herein or not.

Summary of the Invention

According to a first aspect of the invention there is provided an absorbent pad for a wound dressing comprising a central region and at least one distal region, wherein the central region comprises a first fenestration pattern therein comprising at least one fenestration, and wherein the at least one distal region comprises a second different fenestration pattern therein comprising at least one fenestration.

hi the field of advanced wound care, fenestrations provide openings in the absorbent pad and are formed by making one or more cuts in the absorbent pad during its manufacture. The process of forming the fenestrations does not involve removing any surface area of the absorbent pad. As such, the surface area of fenestrated absorbent pads is maintained.

Fenestrations allow for openings to form in the absorbent pad when the absorbent pad is stretched during application and/or wear. Where an absorbent. pad is to be exposed to repeated high degrees of flexion during use (for example, if the absorbent pad is to be applied to anatomical areas requiring a high degree of movement such as the knee, elbow, or hip of a patient etc.), the inventors surprisingly found that certain fenestration patterns result in an unsightly appearance or the visual distortion of the wound dressing surfaces due to movement of the components and materials within the dressing structure. An absorbent pad according to the present invention solves this problem by providing a unique fenestration pattern which provides improved stretch and flexibility of the absorbent pad, whilst maintaining the structural integrity of the absorbent pad and preventing any visual distortion of the absorbent pad surfaces during wear.

Providing a different fenestration pattern in each region of the absorbent pad allows for each region of the absorbent pad to be optimised to provide a particular extensibility and/or stretch direction.

For example, the fenestration pattern of the central region may be configured to provide greater omnidirectional extensibility in the central region. This may allow greater omnidirectional stretch in the application area of the central region, which is beneficial when the central region is applied over a flexing joint (such as an elbow or knee). Alternatively, the fenestration pattern of the distal region may be optimised to have more unidirectional extensibility, which may be more suitable when the distal region is applied along the length of a limb.

For example, a greater number of cuts per unit area and/or a greater number of cuts aligning substantially with the cross direction of the pad may be provided in areas of the absorbent pad which require greater stretch and flexion. On the other hand, in areas of the absorbent pad where stretch and flexion is less of a priority, the number of cuts may be reduced and/or a greater number of cuts aligning substantially with the machine direction may he provided.

By "machine direction" it is meant herein the direction along the length of the material as it travels through the machine during manufacture.

By "cross direction" it is meant herein the direction perpendicular to the machine direction.

Each fenestration pattern comprises an optimum number of cuts and/or optimum direction of cuts that ensures that the inherent strength of the absorbent pad is maintained whilst also providing improved strength and flexibility in the desired directions.

In some embodiments, the first fenestration pattern may comprise a greater number of cuts per unit area than the second fenestration pattern.

In a preferred embodiment, the first fenestration pattern comprises a greater 10 number of cuts aligning substantially with the machine direction of the pad per unit area than the second fenestration pattern.

Such embodiments may ensure that the central region demonstrates improved omnidirectional extensibility.

hi a preferred embodiment, the second fenestration pattern comprises a greater number of cuts aligning substantially with the cross direction of the pad per unit area than the first fenestration pattern.

Beneficially, this ensures that the distal region possesses greater unidirectional stretch and extensibility.

In a most preferred embodiment, the first fenestration pattern comprises a 20 greater number of cuts aligning substantially with the machine direction of the pad per unit area than the second fenestration pattern and the second fenestration pattern comprises a greater number of cuts aligning substantially with the cross direction of the pad per unit area than the first fenestration pattern.

In one embodiment, the orientation of the fenestrations in the central region is different to the orientation of the fenestration in the distal region. In one embodiment, the fenestrations in the central region are orientated to face towards the machine direction of the pad.

In one embodiment, the fenestrations in the distal region are orientated to face towards the cross direction of the pad.

In a preferred embodiment, the fenestrations in the central region are orientated to face towards the machine direction of the pad and the fenestrations in the distal region are orientated to face towards the cross direction of the pad.

Such embodiments ensure that the central region demonstrates omnidirectional extensibility through the orientation of fenestration towards the machine direction of the dressing. Whereas the distal region demonstrates primarily unidirectional extensibility due to the orientation of fenestrations towards the cross direction of the pad.

The first fenestration pattern may comprise at least 1, 2, 3, 4, or at least 5 fenestrations. The first fenestration pattern may comprise no more than 10, 9, 8, 7, 6, 5, or no more than 4 fenestrations. The first fenestration pattern may comprise from 1 - 10, 1 -9, 1 -8, 1 -7, 1 -6, 1 -5, 2 -10, 2 -9, 2 -8, 2 -7, 2 -6, 2 -5, 3 -10, 3 -9, 3 -8, 3 -7, 3 -6, or most preferably from 3 -5 fenestrations.

By "fenestration" it is meant herein a series of cuts.

Each fenestration of the first pattern of fenestrations may be a series of straight-line cuts or curve cuts.

The series of cuts may he branched, linear, or a combination of both.

In some embodiments, at least one fenestration comprises a shape of cuts.

The shape of cuts may be an open shape of cuts (i.e. where the ends do not meet). In such embodiments, the shape of cuts may be independently selected from the group consisting of: a geometrical shape, a polygon, an irregular polygon, an irregular (organic) shape, or parts thereof.

The open shape of cuts may be 1-sided, 2 sided, 3-sided, 4 sided, 5-sided, 6-sided, 7-sided, 8-sided, 9-sided, or 10-sided.

The open shape of cuts may form part of a circle, triangle, square, rectangle, pentagon, a hexagon, a heptagon, an octagon, a nonagon or a decagon.

hi such embodiment, the open shape of cuts may follow the outline of the above shapes with one or more sides removed.

Preferably, the open shape of cuts may form part of a shape selected from the group consisting of a hexagon, circle and combinations thereof.

Beneficially, the inventors found that the provision of an open shape of cuts in the central region improves the aesthetic appearance of the dressing during use and reduces the risk of the dressing catching on bedding and/or clothing during movement.

For example, the inventors observed that the provision of a closed shape of cuts, results in the shape of cuts protruding from the dressing during movement. These protruding cuts are then more likely to catch during movement which can lead to disturbance of the dressing. However, the provision of an open shape of cuts provides sufficient stretch and flexibility without resulting in a protrusion of the shape from the surface of the dressing.

Thus, in a preferred embodiment, the first fenestration pattern does not comprise a fenestration having a closed shape of cuts.

Each cut of the fenestration may be connected to an adjacent cut in such a configuration that the acute angle formed between two adjacent cuts is between 45° to 180', preferably, between 60° to 150 c, preferably the angle formed between two adjacent cuts is approximately 120 °.

In one embodiment, the first pattern of fenestrations may comprise at least one discrete fenestration. In such embodiments, the first pattern of fenestrations may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 discrete fenestrations.

In one preferred embodiment, each of the fenestrations of the first pattern of fenestrations is discrete.

Additionally, or alternatively, at least one of the fenestrations of the first pattern of fenestrations may he connected to its adjacent fenestration.

In such embodiments, the first pattern of fenestrations may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 fenestrations which may he connected to at least one adjacent fenestration.

In such embodiments, at least one fenestration may be connected to its adjacent fenestration by at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 cuts.

Preferably, at least one fenestration is connected to its adjacent fenestration by one cut.

In a preferred embodiment, each of the fenestrations of the first pattern of fenestrations is connected to its adjacent fenestration by at least one cut, most preferably one cut. The first fenestration pattern may be arranged about a central point of the central region of the absorbent pad The first fenestration pattern may be distinct from the or each second fenestration pattern.

In some embodiments, the first fenestration pattern may he connected to the or each second fenestration pattern.

One or more cut(s) of the first fenestration pattern may intersect, adjoin and/or overlap with one or more cut(s) of the second fenestration pattern.

In one embodiment, the first fenestration pattern may he connected to the or each second fenestration pattern by at least one cut in the absorbent pad.

In one embodiment, the first fenestration pattern may he connected to the or each second fenestration pattern by at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 cuts in the absorbent pad.

hi some embodiments, the first fenestration pattern may have symmetry about cardinal axes passing through the central point of the central region of the absorbent 20 pad. The cardinal axes may align with the machine direction and the cross direction of the absorbent pad.

The term "cardinal axes" is used herein to describe two perpendicular axes that intersect at the central point.

In some embodiments, the first fenestration pattern has symmetry about at least one line of symmetry. The first fenestration pattern may have symmetry about two, three, four, five, six, or more than six lines of symmetry. The or each line of symmetry may pass through the central point of the central region of the absorbent pad.

In specific embodiments wherein the absorbent pad is rectangular, the first fenestration pattern may have symmetry about cardinal axes passing through the central point of the central region of the absorbent pad, and wherein the cardinal axes may be parallel with the length or the width of the absorbent pad.

The first fenestration pattern may be arranged about a central point of the central region.

The central point may describe the mid-point of the absorbent pad, wherein each vertex or edge of the absorbent pad is equidistant from its opposing vertex or edge.

In one embodiment, no cuts may pass through the central point of the central region of the absorbent pad.

In a preferred embodiment, the fenestrations of the first pattern of fenestrations are orientated to face towards the machine direction of the dressing.

Surprisingly, the inventors found that orientation of the fenestrations towards 20 the machine direction of the dressing in the central region resulted in improved 360' conformability. This 360" conformability is beneficial in the central region as this region is more likely to cover anatomical areas requiring a high degree of movement or

I I

anatomical areas that are difficult to dress (for example, joints such as hips, knees, elbows, feet, or amputation sites).

The second fenestration pattern may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 fenestrations. The second fenestration pattern may comprise no more than 20, 19, 18, 17, 16, 15, 14, 13, 12, or no more than 11 fenestrations. The second fenestration pattern may comprise from 1 -20, 2 -19, 3 -18, 4 -17, 5 -16, 5 -15, 5 - 14, 5 -13, 5 -12, 5 -11, 5 -10, 6 -20, 6 -19, 6 -18, 6 -17, 6 -16, 6 -15, 6 -14, 6 - 13, 6 -12, 6 -11, 6 -10, 7 -20, 7 -19, 7 - 18, 7 - 17, 7 - 16, 7 -15, 7 -14, 7 -13, 7 - 12, 7 -11, or from 7 -10 fenestration.

Each fenestration of the second fenestration pattern is a series of cuts.

The cut may be a straight-line cut or a curved cut. Preferably, the cut is a straight-line cut.

The series of cuts may be branched, linear, or a combination of both.

hi some embodiments, at least one fenestration of the second fenestration pattern is arranged to form at least part of a shape of cuts.

The shape of cuts may be an open shape of cuts (i.e. where the ends do not meet) or a closed shape of cuts.

hi such embodiments, the shape of cuts may be independently selected from the group consisting of: a geometrical shape, a polygon, an irregular polygon, an irregular (organic) shape, or parts thereof.

The shape of cuts may he 1-sided, 2-sided, 3-sided, 4 sided, 5-sided, 6-sided, 7-sided, 8-sided, 9-sided, or 10-sided.

The shape of cuts may form at least part of a circle, triangle, diamond, square, rectangle, pentagon, a hexagon, a heptagon, an octagon, a nonagon or a decagon.

Preferably, the shape of cuts may form at least part of a hexagon.

Each cut of the fenestrations of the second fenestration pattern may he connected to an adjacent fenestration in such a configuration that the acute angle formed between two adjacent cuts is between 45° to 180°, preferably, between 60° to 150 °, preferably the angle formed between two adjacent cuts is approximately 120 0.

hi one embodiment, the second pattern of fenestrations may comprise at least. one discrete fenestration. In such embodiments, the second pattern of fenestrations may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 discrete fenestrations.

In one preferred embodiment, each of the fenestrations of the second pattern of fenestrations is discrete.

Additionally, or alternatively, at least one of the fenestrations of the second pattern of fenestrations may be connected to its adjacent fenestration.

In such embodiments, the second pattern of fenestrations may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or at least 15 fenestrations which may be connected to at least one adjacent fenestration.

hi such embodiments, at least one fenestration may be connected to its adjacent fenestration by at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or at least 10 cuts.

In a preferred embodiment, each of the fenestrations of the second pattern of fenestrations is connected to its adjacent fenestration by at least one cut, most preferably one cut.

In preferred embodiments, the second fenestration pattern comprises a plurality of connected fenestrations, wherein each fenestration comprises a shape of cuts.

Preferably, the shape of cuts is an open regular polygon shape of cuts, more preferably, an open hexagon (i.e. 5-sided). Each fenestration is connected to its adjacent fenestration by one straight-line cut.

Each fenestration of the second fenestration pattern may have a different orientation to one or more other fenestration.

In a preferred embodiment, each fenestration of the second fenestration pattern may have an opposite orientation to its adjacent fenestration.

An absorbent pad comprising a fenestration pattern having different orientations of fenestrations allows for improved multidirectional stretch and extensibility of the dressing when compared to absorbent pads wherein the fenestrations are arranged in only a single orientation.

In a preferred embodiment, the fenestrations of the second pattern of fenestrations are orientated to face towards the cross direction of the dressing.

Beneficially, this has been observed to provide a greater unidirectional stretch and extensibility.

The fenestrations of the second fenestration pattern may be arranged in a linear arrangement. In such embodiments, the second fenestration pattern may comprise one, two, three, four, or more than four linear arrangements of fenestrations. The or each linear arrangement of fenestrations may extend along the length or the machine direction of the absorbent pad. Providing fenestrations in a linear arrangement along the length or the machine direction of the absorbent pad improves the stretch and extensibility of the absorbent pad in a single direction (i.e. along the direction of the linear arrangement). This improved stretch and flexibility along the length of the absorbent pad is useful when applying the dressing to a wound that is present across a joint.

In some embodiments, the second fenestration pattern has symmetry about at least one line of symmetry passing through the or each distal region. The second fenestration pattern may have symmetry about one, two, three, four, live, six, or more than six lines of symmetry passing through the or each distal region. The or each line of symmetry may pass through the central point of the central region of the absorbent. pad.

In specific embodiments wherein absorbent. pad is substantially rectangular-shaped and comprises two distal regions at opposing ends of the absorbent pad, the second fenestration pattern of each distal region may have symmetry about at least one longitudinal axis passing through the absorbent pad. Alternatively, or additionally, the second fenestration pattern of each distal region may have symmetry about at least one axis perpendicular to the longitudinal axis that passes through the absorbent pad. Each second fenestration pattern may have symmetry about a longitudinal axis passing through each distal region and the central point of the central region of the absorbent pad. Additionally, the two distal regions may have symmetry about an axis that is perpendicular to the longitudinal axis and that passes through the central point of the central region of the absorbent pad As already mentioned, the second fenestration pattern may comprise a greater number of cuts per unit area than the first fenestration pattern.

The or each cut in the absorbent pad of the first and/or second fenestration pattern may have a length of at least 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or at least20 mm. The or each cut in the absorbent pad may have a length of between 3-15 mm. In some embodiments, the absorbent pad comprises cuts of different lengths. Preferably, the absorbent pad comprises cut of similar length or the same length.

In some embodiments, the or each cut in the absorbent pad is formed through the entire depth/thickness of the absorbent pad (i.e. the or each cut extends from the one surface of the absorbent pad to the other surface of the absorbent pad).

An absorbent pad comprising cuts formed through the entire depth/thickness of the absorbent pad allows cuts to open with less resistance and thus provides improved stretch and flexibility.

hi other embodiments, the or each cut in the absorbent pad forms only partially though the depth/thickness of the absorbent pad (i.e. the or each cut does not fully extend through one of the surfaces of the surfaces of the absorbent pad, preferably the or each cut does not fully extend through the surface of the absorbent pad that faces towards the patient's wound/skin).

In some embodiments, the absorbent pad comprises a combination of cuts that form through the entire depth/thickness of the absorbent pad, and cuts that form only through part of the depth/thickness of the absorbent pad.

hi preferred embodiments, the absorbent pad comprises only cuts that form through the entire depth/thickness of the absorbent pad. Absorbent pads comprising cuts that form through the entire depth/thickness of the absorbent pad provide for a dressing with improved stretch and extensibility as each cut can open with less resistance. Other advantages include improved fluid handling capability as the openings formed by the cuts allow moisture from the wound (i.e. wound exudate, etc.) to travel more quickly from the wound site through the openings in the absorbent pad to the upper surface of the wound dressing where the moisture can then escape the wound dressing as moisture vapour.

Each cut may not significantly reduce the structural integrity of the absorbent pad. Each cut may not be obvious or visible to the eye (i.e. the appearance of the integrity of the absorbent pad is maintained).

hi embodiments where absorbent islands arc present at the central region, each cut may form through the entire depth/thickness of the absorbent pad. hi such cases, the wound dressing may further comprise an adhesive backing layer to which the absorbent pad and absorbent islands adhere to. Thus, the adhesive backing layer maintains the first fenestration pattern during manufacture and use.

In some embodiments, the central region is distinct from the or each distal region.

In some embodiments, the central region is directly adjacent to the or each distal region.

In some embodiments, the central region is connected to the or each distal region.

hi some embodiments, the central region intersects and/or overlaps with the or each distal region.

The absorbent pad may comprise one, two, three, four, five, six, or more than six distal region(s). The number of distal regions may depend on the shape of the absorbent pad.

For example: a rectangular-shaped absorbent pad may comprise two distal regions at opposing ends of the rectangle and wherein each distal region is separated by a central region; a cross-shaped absorbent pad may comprise four distal regions wherein each distal region forms along each arm of the cross-shape and is separated from other distal regions by a central region at the cross intersection; and a circular absorbent pad may comprise one distal region that completely surrounds a central region.

In preferred embodiments, the absorbent pad comprises two or more distal regions. Preferably, the two or more distal regions are arranged around the central region and each distal region is equidistant from the or each other distal region.

hi a specific embodiment wherein the absorbent pad is substantially rectangular in shape, the absorbent pad may comprise a central region and two distal regions, wherein each distal region is adjacent to the central region and at opposing sides of the central region. The central region may be centred around the central point of the absorbent pad and may separate each distal region which are present at each end of the absorbent pad.

In embodiments where there is more than one distal region, one or more of the distal region( s) may comprise the same fenestration pattern.

hi some embodiments where there is more than one distal region, one or more of the distal region(s) may comprise a third fenestration pattern.

The third fenestration pattern may be different to the second fenestration pattern.

hi some embodiments, the distal regions may comprise a third, fourth, fifth, sixth, seventh, eighth, ninth or tenth fenestration pattern.

The third, fourth, fifth, sixth, seventh, eighth, ninth or tenth fenestration pattern may be different or the same as at least one other fenestration pattern.

The third, fourth, fifth, sixth, seventh, eighth, ninth or tenth fenestration pattern may comprise one or more features described herein in relation to the second fenestration pattern. Accordingly, reference to the second fenestration pattern above may similarly refer to the third, fourth, fifth, sixth, seventh, eighth, ninth or tenth fenestration pattern.

hi preferred embodiments, each distal region comprises a similar pattern of fenestrations. Most preferably, each distal region comprises the same pattern of 20 fenestrations.

The absorbent pad may comprise a wound facing surface that faces towards a physiological target site (e.g. a wound) and an upper surface that faces away from the physiological target site. The first and second fenestration patterns may form through the wound facing surface of the absorbent pad and/or the upper surface of the absorbent pad.

The absorbent pad may absorb wound exudate (e.g. blood, plasma and the like).

The wound facing surface of the absorbent pad may be applied directly to a physiological target site such as a wound. hi some embodiments, the physiological target site is present at or near an anatomical area requiring a high range of movement, such as a joint (e.g. hip, ankle, or knee).

In some embodiments, the absorbent pad is substantially the shape of a circle, a regular polygon. an irregular polygon. a geometric shape, or an irregular (organic shape). The shape of the absorbent pad depends on its intended use and to which anatomical area it is to be applied.

For post operative use wherein the absorbent pad is to be applied to a physiological target site comprising a straight line surgical incision, the absorbent pad may be substantially rectangular. For such uses, the rectangular shape ensures that the absorbent pad covers the straight-line incision and provides greater stretch and extensibility of the dressing along the line of the incision during use.

The absorbent pad may comprise curved corners to prevent the corners from detaching from the surface of the patient's skin during use.

In some embodiments, the absorbent pad has a length of at least 60 mm, 80 mm, mm, 120 mm, 140 mm, 160 mm, 180 min, 200 mm, 220 mm, 240 mm, 260 mm, or 280 mm, 300 mm, 320 mm, 340 mm, 360 mm, or at least 380 mm. The absorbent pad may have length of no more than 400 mm, 380 mm, 360 mm, 340 mm, 320 mm, 300 mm, 280 mm, 260 mm, 240 mm, 220 mm, 200 mm, 180 mm, 160 mm, 140 mm, 120 mm, 100 mm, or no more than 80 mm. Preferably, the absorbent pad may have a length of between 100-300 mm hi some embodiments, the absorbent pad has a width of at least 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 120 mm, 140 mm, 160 mm, or at least 180 mm. The absorbent pad may have a width of no more than 200 mm, 180 mm, 160 mm, 140 mm, 120 mm, 100 mm, 90 mm, 80 mm, 70 mm, 60 mm, 50 mm, or no more than 40 mm. Preferably, the absorbent pad has a width of between 40-80 mm.

hi some embodiments, the absorbent pad has a thickness of at least 1.0 mm, 1 2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4.0 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm, 5.0 mm, 5.2 mm, 5 4 mm, 5 6 mm, or at least 5.8 mm. The absorbent pad may have a thickness of no more than 10.0 mm, 9.0 mm, 8.0 mm, 7.0 mm 6.0 mm, 5.8 mm, 5.6 mm, 5.4 mm, 5.2 mm 5 0 mm 4 8 mm 4 6 mm, 4 4 mm 4 2 mm 4 0 mm 3 8 mm 3 6 mna 3.4 mm, 3.2 mm, 3.0 mm, 2.8 mm, 2.6 mm, 2.4 mm, 2.2 mm, 2 0 mm, 1.8 mm 1 6 mm, 1.4 mm, or no more than 1.2 mm. The absorbent pad may have a thickness of between 1.5-5.5 mm.

The absorbent pad may additionally comprise a perimeter region. The perimeter region may surround the central region and each distal region. The perimeter region may he absent of fenestrations.

The absorbent pad may comprise one or more absorbent materials. An absorbent material is used herein to refer to a physiologically acceptable material that is capable of absorbing liquid, such as wound exudate, and which is capable of absorbing liquid to greater than about 500% by weight of the absorbent material, and with a liquid retention of greater than about 40%.

The absorbent material may comprise a fibrous, foam, non-woven or woven material.

The absorbent material may be in the form of fibres. Typically, the absorbent material may be in the form of non-woven fibres. The length of the fibres can be up to about 100 mm, and is typically from about 20-75 mm, nore typically from about 3251 mm.

The absorbent material may be a superabsorbent material. A superabsorbent material is used herein to refer to a hydrophilic material that is water-swellable, but not water soluble, and which is capable of absorbing liquid to greater than about 2000% by weight of the superabsorbent material, preferably greater than about 2500% with a liquid retention of greater than about 85%, preferably greater than about 90%. Reference to an absorbent material also includes reference to a superabsorbent material unless expressed otherwi se.

The superabsorbent material may be selected from polymeric materials such as poly(vinyl alcohol) (PVA), poly(ethylene oxide) (PEO) and poly(acrylic acid).

The superabsorbent material may be chemically modified. For example, the superabsorbent material may be a polymeric material obtained by graft polymerisation 20 of acrylic acid onto a chain of carboxymethyl cellulose.

The superabsorbent material may comprise a chemically modified material selected from starch, cellulose and polymeric materials such as poly(vinyl alcohol) (PVA), poly(ethylene oxide) (PEO), and poly(acrylic acid).

The poly(acrylic acid) may he a partially neutralised, lightly cross-linked poly(acrylic acid).

The superabsorbent material may he in the form of fibres. Typically, the superabsorbent material is in the form of non-woven fibres. The length of the fibres can be up to about 100 m 1, and is typically from about 20-75 mm, more typically from about 32-51 mm.

The superabsorbent material may comprise or consist of an air laid nonwoven fibre. By air laid nonwoven fibre, it is meant a continuous web formed by a mixture of short fibres and/or 100% pulped fibres. The absorbent material may comprise a chemical pulp made from long fibre softwoods. Preferably, the absorbent material may he a fluff pulp. By the term "fluff pulp", it is meant a chemical pulp made of cellulose fibres obtained from long softwoods.

hi preferred embodiments, the absorbent materials may comprise a superabsorbent material and fluff pulp. Preferably, the absorbent material of the present invention comprises a poly(acrylic acid) and fluff pulp fibre blend.

In some embodiments, the absorbent material may consist of or comprise a gelling or semi-gelling material.

The term 'gellina material' is used herein to refer to a material in which substantially all of the components therein may gel upon contact with water or body fluid(s). For example, it may comprise a fibrous material wherein substantially all of the fibres are capable of gelling upon contact with water or body fluid(s).

The term 'semi-gelling' is used herein to refer to a material that comprises a mixture of components, some of which gel upon contact with water or body fluid(s) and some of which do not. For example, a semi-gelling absorbent material may comprise a combination of fibres, some of which gel upon contact with water or body 'kicks) and some of which do not.

The gelling or semi-gelling material may be in any available form, such as for example, fibres, granules, powder, flakes, sheet, foam, freeze dried foam, compressed foam, film, perforated film, beads, and combinations of two or more of the aforesaid.

The gelling or semi-gelling material may be selected from carboxymethylcellulose, alginate, chitosan salt or a chitosan salt derivative.

Typically, the gelling or semi gelling material is in the form of fibres. The fibres can be of any desired diameter or length and can be formed into a textile fabric or a pad for use. The fibres may be woven or non-woven. Preferably, the fibres are non-woven. The absorbent pad may be a single layer. The absorbent pad may comprise more than one layer. The absorbent pad may comprise two, three, four, five, six, seven, eight, nine, ten, or more than ten layers. The absorbent pad may comprise a plurality of layers. Each layer may comprise an absorbent material.

hi some embodiments each layer of the absorbent. pad is fenestrated.

hi some embodiments, at least one layer of the absorbent pad does not comprise fenestrations.

The absorbent pad may comprise decoupled layers.

Alternatively, the absorbent pad may have a laminate structure.

The layers of the absorbent pad may he bonded together using an adhesive between the layers. The surfaces of the absorbent pad which are to be bonded may be fully or partially coated with an adhesive.

The adhesive may be any suitable physiologically acceptable adhesive known in the art. The adhesive may he any suitable skin-contact adhesive known in the art.

The adhesive may be a silicone adhesive (such as a polydimethylsiloxane adhesive), an acrylic adhesive, a polyurethane adhesive, a hydrogel adhesive, or any combinations thereof.

The adhesive may be in the form of a powder, a liquid, a web or a net. The web 10 may be an acrylic web.

The adhesive may comprise a meltable adhesive and/or a pressure sensitive adhesive, or the like. The meltable adhesive may be a heat-bonding adhesive or a heat-activated adhesive. The pressure sensitive adhesive may be acrylic based.

The adhesive may be a thermal adhesive. The adhesive may comprise any suitable thermal adhesive known in the art. For example, the thermal adhesive may be a thermoplastic adhesive, such as polycaprolactonc.

The adhesive may be a powder. The powder may be scattered onto either or both surfaces of the absorbent pad to he attached and then passed through a heat tunnel to laminate the layers of the absorbent pad.

Preferably the adhesive is a polycaprolactone based adhesive. Preferably still, the adhesive is a schaetti fix 352 polycaprolactone adhesive that is scattered between the layers of the absorbent pad.

According to a second aspect of the invention, there is provided a method of manufacturing the absorbent pad of the first aspect of the invention, the method comprising; applying a first fenestration pattern to the central region of the absorbent pad and applying a second fenestration pattern to the distal region of the absorbent pad.

The application of the first and second pattern of fenestrations may occur in a single step. The application of the first and second pattern of fenestrations may occur simultaneously.

The first and/or second fenestration patterns may be applied to the absorbent pad using any suitable known method in the field. For example, the first and/or second fenestration pattern may be applied using at least one cutting method selected from the group consisting of: die cutting, laser cutting, ultrasonic cutting, or any combination thereof.

Preferably, the first and second fenestration patterns are applied to the dressing using a the cutter, wherein the die cutter comprises both the first and second fenestration patterns.

The method may further comprise applying a backing layer to the absorbent. pad. The backing layer may comprise an adhesive layer to adhere the absorbent pad to the physiological target site. The application of the backing layer to the absorbent pad may occur before or after applying the first and/or second pattern of fenestrations to the absorbent pad.

According to a third aspect of the present invention, there is provided a wound dressing comprising an absorbent pad according to a first aspect of the present invention.

In some embodiments, the wound dressing may further comprise a wound contact layer. The wound contact layer may be applied to the wound facing surface of the absorbent pad.

The wound contact layer may comprise an adhesive for adhering the absorbent pad to the physiological target site of a patient. Typically, the wound contact layer is fully or partially coated with an adhesive.

The wound contact layer may he placed in direct or indirect contact with the wound. The wound contact layer may directly contact the wound.

The wound contact layer may have a laminate structure. The laminate structure 10 may comprise two or more layers. The laminate structure may comprise two, three, four, five, six, seven, eight, nine, ten or more layers.

Preferably, the wound contact layer comprises a trilaminate structure. Such embodiments may refer to the wound contact layer as a wound contact trilaminate. The trilaminatc structure may have a central carrier layer, a proximal layer and a distal layer.

The proximal layer may comprise an adhesive for contacting and securing the wound contact layer to the wound and/or the skin surrounding the wound. The distal layer may comprise an adhesive for securing the wound contact layer to the absorbent pad and/or backing layer.

The wound contact layer may comprise one or more perforations to facilitate 20 the passage of wound exudate to the absorbent pad. The wound contact layer may comprise a plurality of perforations.

The perforations may he arranged in one or more directions on the wound contact layer. The perforations may be arranged in a linear repeating pattern. Alternatively, the perforations may be arranged in a random configuration.

The perforations may extend fully through the wound contact layer.

Alternatively, the perforations extend partially through the wound contact layer.

The perforations may be substantially circular.

The perforations in the wound contact layer increases the rate of uptake of wound exudate from the wound contact layer, thereby improving the effectiveness of the wound dressing. The perforations in the wound contact layer also reduce the adhesion of the wound contact layer to the wound and/or the skin surrounding the wound. Advantageously, this reduces damage to the wound area upon removal of the dressing.

The distal layer of the wound contact tr laminate preferably comprises an adhesive. The adhesive is preferably an acrylic adhesive. The adhesive is also preferably a pressure sensitive adhesive. However, the adhesive may comprise any of the adhesives referred to herein and be applied by any of the methods referred to herein.

The proximal layer of the wound contact trilanainate preferably comprises a biocompatible pressure sensitive adhesive. The adhesive may be any suitable skin-contact adhesive known in the art. The adhesive may comprise a silicone adhesive or polyurethane adhesive. Typically, the adhesive is a silicone adhesive, such as polyd methylsiloxane. Alternatively, the adhesive can he an acrylic adhesive, a polyurethane adhesive, a hydrogel adhesive such as for example an atraumatic hydrogel adhesive, or any combinations thereof. The adhesive is intended to create a tight seal between the wound dressing and the patient's skin surrounding the wound.

The proximal layer of adhesive may be coated onto the proximal surface of the carrier layer with a coat weight of from 30 to 300gsm.

The carrier layer of the wound contact trilaminate may comprise, or consist of, a polyurethane film.

The wound contact layer is not limited to a particular size or shape unless specifically defined herein. The wound contact layer may take a variety of sizes or shapes as desired or as appropriate. Typically, the wound contact layer has a generally rectangular shape.

The wound dressing may comprise a wicking layer. The wicking layer may assist with the distribution of liquid throughout the components of the dressing.

The wicking layer may have a high lateral and vertical wicking rate to increase the absorption of wound exudate from the physiological target site and transmit wound exudate to the absorbent pad.

The wicking layer may be located within the absorbent pad.

The wicking layer may he continuous and contain no fenestrations. Alternatively, the wicking layer may be discontinuous and contain one or more cuts. The wicking layer may comprise one or more cuts as described herein.

In some embodiments, the wound dressing may further comprise a backing layer. The backing layer may comprise a border portion that extends beyond the edges of the absorbent pad, with an adhesive located on the wound facing surface of the border portion for adhering the dressing to the skin/physiological target site of a patient.

The hacking layer may comprise a water vapour permeable, waterproof film. The backing layer may comprise or consist of polyurethane.

The backing layer may serve as a bather and may be operable to prevent microorganisms, such as bacteria, from entering the wound dressing from an external source, such as clothing, etc. Further, the hacking layer is also operable to retain wound exudate within the wound dressing and prevent it leaching out of the wound dressing.

The hacking layer may be gas-permeable. The hacking layer may be substantially impermeable to microorganisms, such as bacteria. The backing layer may be substantially impermeable to liquids.

The permeability of the backing layer to gases, such as air and moisture vapour, permits the transmission of moisture vapour through its structure. This facilitates the transpiration of wound exudate from the dressing into the external environment.

Beneficially, this increases the breathability of the dressing and prevents the saturation of the dressing with exudate, which leads to a reduced number of dressing changes.

The backing layer may have a moisture vapour transmission rate in the range of 50 g/100 cm= per 24 hours to 250 g/100 cm= per 24 hours. Good results are observed when the backing layer has a moisture vapour transmission rate in the range of 80 g/100 20 cm-per 24 hours to 220 a/100 cm-per 24 hours. In a preferred embodiment, the backing layer has a moisture vapour transmission rate of 100 g/100 cm= per 24 hours to 200 g/100 cm2 per 24 hours.

The hacking layer may comprise a material that is gas-permeable and liquid-impermeable. The backing layer may also comprise a material that is microorganism-impermeable.

The backing layer may comprise, or consist of, any biologically acceptable polymer material that is liquid-and/or microorganism-impermeable but gas-permeable.

Suitable biologically acceptable polymer materials for the backing layer may be selected from the group consisting of polyurethane and polyethylene.

The backing layer may have a thickness of from 5-50 microns, preferably 10-30 microns.

The backing layer may have a surface area greater than that of the absorbent region.

hi some embodiments, the wound dressing may further comprise a removable protecting layer. The removable protecting layer may be a peelable protecting layer. The removable protecting layer may cover the wound facing surface of the absorbent pad and the wound facing surface of the border portion of the backing layer. The protecting layer facilitates storage of the wound dressing without detriment to the absorbent pad and/or the skin-contact adhesive on the backing layer. The protecting layer is intended for removal prior to application of the dressing to a wound.

The removable protecting layer may comprise two or more parts that arc separately removable via one or more tabs.

The wound dressing may further comprise one or more additional components as desired or appropriate. Such additional components may include, but are not limited to, pharmaceutical agents; wetting agents such as surfactants; growth factors; cytokincs; agents which absorb agents which delay healing such as MMP's (matrix metdloproteinases) and elastase; and/or another wound dressing component, such as calcium, vitamin K, fibrinogen, thrombin, factor VII, factor VIII, clays such as kaolin, oxidised regenerated cellulose, gelatin, or collagen, etc. The wound dressing may comprise decoupled layers.

The layers of the wound dressing may form a laminate structure.

Typically, each layer of the wound dressing may be fully or partially coated with an adhesive to adhere it to the other layer(s) or component(s) of the wound dressing. Preferably, the adhesive may he pattern coated onto the or each layer.

The adhesive may be any suitable adhesive known in the art. The adhesive may comprise any suitable skin-contact adhesive known in the art.

The adhesive may he a silicone adhesive, such as a polydimethylsiloxane adhesive. Alternatively, the adhesive may be an acrylic adhesive, a polyurethane adhesive, a hydrogel adhesive, or any combinations thereof.

The adhesive may be in the form of a powder, a liquid, a web, or a net. The web may be an acrylic web.

The adhesive may he a powder. The powder may he scattered onto either or both surfaces of the layers to be attached and then passed through a heat tunnel to laminate the layers of the wound dressing.

In preferred embodiments, the adhesive is selected from the group consisting of an acrylic adhesive, a polycaprolactone based adhesive, and combinations thereof.

According to a fourth aspect of the present invention there is provided a method of manufacturing a wound dressing, said method comprising the steps of adhering an absorbent pad according to the first aspect of the invention to a backing layer as described herein.

The absorbent pad may be adhered to the backing layer using an adhesive as described herein.

The method of manufacturing a wound dressing may comprise the further step of applying to the wound facing surface of the absorbent pad a wound contact layer as described herein.

The method of manufacturing a wound dressing may comprise the further step of applying to a wound facing surface of the absorbent pad (or the wound contact layer if present) a removable protecting layer as described herein.

The wound dressing may he cut and shaped as desired or as appropriate.

According to a fifth aspect of the present invention, there is provided a method of absorbing fluid (e.g. wound exudate) discharged from a physiological target site of a human or animal body, or of stemming a flow of a fluid discharged from a physiological target site of a human or animal body, comprising applying to the physiological target site an absorbent pad according to the first aspect of the invention or a wound dressing according to the third aspect of the invention.

According to a sixth aspect of the present invention, there is provided a use of an absorbent pad according to a first aspect of the invention, or a wound dressing according to the third aspect of the invention, in absorbing fluid discharged from a physiological target, or in stemming a flow of a fluid discharged from a physiological target site.

According to a seventh aspect of the present invention, there is provided an absorbent pad according to the first aspect of the invention, or a wound dressing according to a third aspect of the invention, for use in absorbing fluid discharged from a physiological target site, or for use in stemming a flow of a fluid discharged from a physiological target site.

The physiological target site may be a wound at a joint, such as a hip, elbow or knee joint.

The further aspects of the present invention may incorporate any of the features of the other aspects of the invention described herein as desired or as appropriate.

Detailed Description of the Invention

In order that the invention may he more clearly understood an embodiment/embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 illustrates a bottom view of a first embodiment of an absorbent pad according to the first aspect of the present invention.

Figure 2 illustrates a bottom view of a second embodiment of an absorbent pad according to the first aspect of the present invention.

Figure 3 illustrates a bottom of an absorbent pad not according to the present invention comprising a single fenestration pattern.

Figure 4 illustrates a wound dressing comprising an absorbent pad according to the present invention.

Figure 5 is a graphical representation showing the extensibility of Example 1 and

Reference Example 2.

Figure 6 is a graphical representation showing the 360° conformability of the central region of Example 1 and Reference Example 2.

Figure 7 is a graphical representation showing the 360° conformability of the central region of Example 1 compared with the distal region of Example 1.

Figure 8 is a graphical representation showing the absorbency of Example 1 and

Reference Example 2.

Figure 9 is a graphical representation showing the fluid handling of Example 1 and Reference Example 2.

Referring to Figure I, there is shown a rectangular-shaped absorbent pad 1 according to a first embodiment of the first aspect of the present invention. The absorbent pad 1 comprises a wound facing surface 2. The wound facing surface 2 of the absorbent pad 1 comprises a central region 3 having a first fenestration pattern therein and two distal regions 4a,4b having a second fenestration pattern therein.

The first fenestration pattern comprises fenestrations 5a, 5b formed by a plurality of cuts which form a 4-sided open hexagon shape. The 4-sided open hexagon shape faces toward the machine direction of the absorbent pad 1. The fenestrations 5a, 5b are connected to its adjacent fenestration by a single cut 6.

The first fenestration pattern comprises a greater number of cuts per unit area, which substantially align with the machine direction of the dressing.

The second fenestration pattern comprises fenestrations 7a, 7b formed by a plurality of cuts arranged in the shape of a 5-sided open hexagon. The second fenestration pattern comprises two linear arrangements of four connected fenestrations 7a, 7b. Each adjacent fenestration 7a, 7b of the second fenestration pattern has a different orientation. Each fenestration 7a,7h is connected to its adjacent fenestration by a single cut 8.

The second fenestration pattern of each distal region comprises a higher number of cuts per unit area which substantially align with the cross direction of the pad 1 I 5 compared to the first fenestration pattern.

The first fenestration pattern is connected to the second fenestration pattern by a cut 9 at four different points.

The first fenestration pattern has symmetry about cardinal axes passing through the central point 10.

Each second fenestration pattern has symmetry about a longitudinal axis passing through the central point 10.

The two distal region regions 4a,4h have symmetry about an axis perpendicular to the longitudinal axis that passes through the central point 10.

Referring to Figure 2, there is shown a rectangular-shaped absorbent pad 21 according to a first embodiment of the first aspect of the present invention. The absorbent pad 21 comprises a wound facing surface 22. The wound facing surface 22 of the absorbent pad 21 comprises a central region 23 having a first fenestration pattern therein and two distal regions 24a, 24b having a second fenestration pattern therein.

The first fenestration pattern comprises a fenestration 25a formed by a plurality of cuts which form a 4-sided open hexagon shape and a fenestration 25b comprising two cuts forming a 2-sided open diamond shape (i.e. an arrowhead shape). The 4-sided open hexagon shape and the open 2-sided diamond shape face toward the machine direction of the absorbent pad 1. The fenestrations 25a, 25b are connected to its adjacent fenestration by a single cut 26.

The second fenestration pattern comprises fenestrations 27a, 27b formed by a plurality of cuts arranged in the shape of a 5-sided open hexagon. The second fenestration pattern comprises two linear arrangements of six connected fenestrations 27a, 27h. Each adjacent fenestration 27a, 27h of the second fenestration pattern has a different orientation. Each fenestration 27a, 27b is connected to its adjacent fenestration by a single cut 28.

The second fenestration pattern of each distal region comprises a higher number of cuts per unit area which substantially align with the cross direction of the pad 1 compared to the first fenestration pattern.

The first fenestration pattern is connected to the second fenestration pattern by a cut 29 at four different points.

Referring to Figure 3, there is shown a rectangular-shaped absorbent pad 30 not according to the present invention. The absorbent pad 30 comprises a wound facing surface 31. The wound facing surface 31 of the absorbent pad 30 comprises a single fenestration pattern comprising a plurality of crescent shaped fenestration 32.

Referring to Figure 4, there is shown a wound dressing 40 comprising a backing layer 41, an absorbent pad 42 having a laminate structure comprising a fenestrated polyurethane material 43 having a fenestration pattern according to the present invention laminated to a superabsorbent material 44 using a schactti fix 352 polycaprolactone adhesive, and a wound contact layer 45 on the wound facing surface of the absorbent pad 42 for securing the dressing to the wound site. The backing layer 41 comprised a polyurethane film and was adhered to the absorbent pad via a pattern coated acrylic adhesive.

The wound contact layer 45 has a trilaminate structure.

The trilaminate wound contact layer 45 comprises a curler layer 46, a proximal layer 47, and a distal layer 48. The carrier layer 46 comprises a polyurethane film, the proximal layer 47 comprises an atraumatic polydimethylsiloxane adhesive and the distal layer 48 comprises an acrylic adhesive.

The distal layer 48 facilitates the adherence of the absorbent pad to the distal surface 48 of the wound contact layer 45 and also the adherence of the wound contact layer 45 to the backing layer 21.

The wound contact layer 45 may contain perforations (not shown).

In use, when a human or animal suffers a penetrating wound, the wound dressing 40 is applied to the wound, with the wound contact layer 45 being placed in direct contact with the wound. Upon application to a wound, the pattern of fenestrations of the absorbent pad 42 enable the dressing to stretch in all directions and readily conform to the contours of the anatomical area to which the wound dressing 40 is being applied. Once in place, force can be applied to the wound dressing 40 as necessary.

Examples Example

The absorbent pad of Figure 1 was incorporated into a wound dressing as described in Figure 4. The wound dressing comprised a polyurethane backing layer, and an absorbent pad having a laminate structure comprising a superabsorbent material and a polyurethane layer having a fenestration pattern as shown in Figure 1. The wound facing surface of the absorbent pad was adhered to a wound contact layer having a trilaminate structure comprising a carrier layer of polyurethane film, a proximal layer of atraumatic polydimethylsiloxane adhesive and a distal layer of acrylic adhesive. The backing layer was adhered to the absorbent pad via a pattern coated acrylic adhesive. The polyurethane material of the absorbent pad was laminated to the superabsorbent material using a a schaetti fix 352 polycaprolactone adhesive. The backing layer had a border portion that extends beyond the edges of the absorbent pad for securing the backing layer to the wound contact layer.

Reference Example 2

The absorbent pad of Figure 3 was incorporated into a wound dressing as described in Figure 4. The wound dressing comprised a polyurethane backing layer, and an absorbent pad having a laminate structure comprising a superabsorbent material and a polyurethane layer having a fenestration pattern as shown in Figure 3. The wound facing surface of the absorbent pad was adhered to a wound contact layer having a trilaminate structure comprising a carrier layer of polyurethane film, a proximal layer of atraumatic polydimethylsiloxane adhesive and a distal layer of acrylic adhesive. The backing layer was adhered to the absorbent pad via a pattern coated acrylic adhesive.

The polyurethane material of the absorbent pad was laminated to the superabsorbent material using a a schaetti fix 352 polycaprolactone adhesive. The backing layer had a border portion that extends beyond the edges of the absorbent pad for securing the backing layer to the wound contact layer. Extensibility The extensibility of wound dressings prepared according to Example 1 and Reference Example 2 was measured according to the following test method.

Test method: (1) Mark 2 lines on the full dressing being tested each measuring lOmm from opposite ends of the dressing in the direction of the test. Measure the distance between the two marks to the nearest 0.5mm (L1).

(2) Remove the release liners from the dressing and allow it to relax for a minimum of 300s.

(3) Clamp the specimen outside the marks (drawn in step I) into the jaws of the tensile testing machine.

(4) Calculate 20% of LI and input into program as the extension distance (L2) to stretch the dressing by 20%.

(5) Extend the specimen by L2 using an extension rate 01(300 +/-15) mm/min.

(6) Record the maximum load (ML) to the nearest 0.1N.

The tests were repeated six times and an average extensibility was calculated.

The results of the extensibility testing for the dressings are displayed in Table Extensibility (N)

Example 1 23.38

Reference Example 29.17

Table 1

Example 1 of the present invention showed significantly increased extensibility over the reference example having only a single fenestration pattern. The results in Table 1 have been graphed and can be seen in Figure 5. The graph shows the significant improvement in extensibility of an absorbent pad of the present invention.

Conformability Test The 360' conformability of the fenestration pattern of the central region of Example 1 was compared to the fenestration pattern of example 2 using the following test method.

Test method: (1) Place 360 conformability rig (flat baseplate with circular hole in the centre) onto tensile testing machine.

(2) Attach testing hemisphere to tensile tester (positioned directly above the hole in the base plate) (3) Remove the release liners of the dressing sample.

(4) Apply dressing sample wound contact face up on to the baseplate (placing the section of dressing to be tested centrally over the hole) (5) Cover dressing sample and baseplate with 2nd plate and fix into place.

(6) Lower the testing hemisphere to 3mm above the sample.

(7) Zero the load and lower the hemisphere onto the sample, recording the loads at the following strains 5%, 10%, 15%, 20%, 25%, 30%, 35% & 40%.

The tests were repeated six times and an average conformability was calculated.

The results of the conformability testing for the dressings are displayed in Table 2.

360" Conformability Strain (%) Example 1 (central Reference Example 2 region) 6.022 6.256 13.329 14.246 21.903 24.044 31.287 34.255 39.894 42.522 44.848 44.484 47.384

Table 2

The fenestration pattern of the central region of Example 1 of the present invention showed significantly increased 360° conformability over the fenestration pattern of Reference Example 2. The results in Table 2 have been graphed and can be seen in Figure 6. The graph shows the significant improvement in conformability of a fenestration pattern of the central region of the present invention. This is shown in the lower force required to extend the dressing in all directions.

The 360" conformability of the fenestration pattern of the central region of the dressing of Example 1 was also compared with the 360° conformability of the fenestration pattern of the distal region of Example 1. The thickness of the polyurethane layer of the dressing was increased from 1.7mm to 2 5mm for the below 360 conformability test.

The conformability was measured and calculated using the same method as described above. The results of the conformability testing are displayed in Table 3 15 below.

360° Conformability Strain (%) Example I (central Example 1 (distal region) region) 5.81 7.20 11.13 14.48 19.87 22.35 26.63 30.44 33.10 38.36 36.70 42.19 41.86 46.71 43.86 NA

Table 3

As shown above, the fenestration pattern of the central region of Example 1 demonstrated increased 360" conformability when compared with the fenestration pattern of the distal region. The results in Table 3 have been graphed and can be seen in Figure 7. The improved conformability in the central region is seen to he beneficial as the requirements of the distal region of the dressing are typically more unidirectional (such as along a length of a leg or arm) whereas the central region typically requires greater omnidirectional extensibility as it is typically applied over a flexing joint (such as an elbow or knee).

Absorbency The total absorbency of the dressings was assessed according to the following test method.

Test method: (1) Remove release liners from a dressing and record the weight (W1).

(2) Add Solution A (pre warmed to 37°C (±1°C) to a testing tray to a depth of mm (3) Add the dressing, wound contact side facing downwards, to the tray.

(4) Incubate the dressing at 37°C (±1°C) RH 60% for 30 minutes.

(5) Lift dressings up with tweezers and let drain for 1 minute.

(6) Record the mass of the dressings after absorption (W2).

(7) Calculate the full dressing absorbency in g/dressing using the equation below: Absorbency (g/dressing) = W2-W1 The tests were repeated six times and the average absorbency was calculated.

The average absorbency of the dressings are displayed in Table 4 below.

Average absorbency (g/dres sing)

Example 1 57.600

Reference 59.952

Example 2

Table 4

As shown in Table 4, Example 1 of the present invention showed comparable absorbency to a Reference Example 2. This demonstrates that the pad of the present invention results in improved extensibility and conformability without compromising the fluid handling abilities of the dressing. The results in Table 4 have been graphed and can he seen in Figure 8. The graph shows the comparable absorbency of a dressing comprising a pad of the present invention.

Fluid Handling The total fluid handling of each sample was calculated using the formula: Average Total Fluid Handling = Average MVTR + Average Absorbency The total fluid handling of the absorbent pads is displayed in Table 5 below.

Average MVTR (g/100cm2/24hr) Average Absorbency (g/100cm2/24hr) Average Tot al Fluid Handling (g/100crn2/2411r) Example 1 76.050 38.292 114.342 Reference 75.390 44.500 119.890

Example 2

Table 5

Example 1 of the present invention showed comparable total fluid handling to Reference Example 2. This demonstrates that the pad of the present invention results in improved extensibility and conformability without compromising the fluid handling properties of the dressing. The results in Table 5 have been graphed and can he seen in Figure 9.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention.

Claims

CLAIMS1. An absorbent pad for a wound dressing comprising a central region and at least one distal region, wherein the central region comprises a first fenestration pattern therein comprising at least one fenestration, and wherein the at least one distal region comprises a second different fenestration pattern therein comprising at least one fenestration.
2. An absorbent pad according to claim I, wherein at least one fenestration of the first fenestration pattern comprises an open shape of cuts.
3. An absorbent pad according to claim 2, wherein the open shape of cuts forms part of a hexagon and comprises 4 sides.
4. An absorbent pad according to any preceding claim, wherein at least one fenestration of the second fenestration pattern comprises an open shape of cuts.
5. An absorbent pad according to claim 4, wherein the open shape of cuts forms part of a hexagon and comprises 5 sides.
6. An absorbent pad according to any preceding claim, wherein the first and/or second fenestration pattern comprises a linear arrangement of fenestrations.
7. An absorbent pad as claimed any preceding claim, wherein the first fenestration pattern comprises a greater number of cuts aligning substantially with the machine direction of the pad per unit area than the second fenestration pattern, preferably the first fenestration pattern comprises a greater number of cuts aligning substantially with the machine direction of the pad per unit area than the second fenestration pattern and the second fenestration pattern comprises a greater number of cuts aligning substantially with the cross direction of the pad per unit area than the first fenestration pattern.
8. An absorbent pad according to any preceding claim, wherein the fenestrations in the central region are orientated to face towards the machine direction of the pad and the fenestrations in the distal region are orientated to face towards the cross direction of the pad.
9. An absorbent pad according to any preceding claim, wherein each fenestration is connected to its adjacent fenestration by at least one cut.
10. An absorbent pad according to any one of claims 1-9, wherein each fenestration is discrete.
11. An absorbent pad according to any preceding claim, wherein the firs( fenestration pattern is centred around a central point of the central region.
12. An absorbent pad according to any preceding claim, wherein the first fenestration pattern of the central region has symmetry about at least one line of symmetry passing through the central region, or preferably about at least one line of symmetry passing through the central point of the central region.
13. An absorbent pad according to any preceding claim, wherein the first fenestration pattern has symmetry about a cardinal axis passing through the central point of the central region.
14. An absorbent pad according to any preceding claim, wherein the second fenestration pattern has symmetry about at least one line of symmetry passing through the distal region.
15. An absorbent pad according to any preceding claim, wherein the absorbent pad comprises two or more distal regions and wherein each distal region is arranged around the central region and wherein each distal region is equidistant from the other distal region(s).
16. An absorbent pad according to any preceding claim, wherein the absorbent pad is substantially rectangular and comprises a central region and two distal regions, wherein each distal region is adjacent to the central region and at opposing sides of the central region.
17. An absorbent pad according to any preceding claim, wherein the absorbent pad comprises at least one absorbent material, or preferably a superabsorbent material.
18. An absorbent pad according to claim 17, wherein the absorbent pad comprises more than one layer of an absorbent material and/or superabsorbent material, and wherein the layers of the absorbent pad form a laminate structure.
19. A method of manufacturing an absorbent pad according to any one of claims 1- 18, the method comprising; applying a first fenestration pattern to the central region of the absorbent pad and applying a second fenestration pattern to the distal region of the absorbent pad.
20. A wound dressing comprising an absorbent pad according to any one of claims 1-18.
21. A wound dressing according to claim 20, wherein the wound dressing further comprises a backing layer; and optionally wherein the backing layer comprises a border portion that extends beyond the edges of the absorbent pad, with an adhesive located on the wound facing surface of the border portion.
22. A method of manufacturing a wound dressing according to claim 21, comprising the steps of adhering an absorbent pad as described herein to a backing layer.
23. A method of absorbing fluid discharged from a physiological target site of a human or animal body, or of stemming a flow of a fluid discharged from a physiological target site of a human or animal body, comprising applying to the physiological target site an absorbent pad according to any one of claims 1-18 or a wound dressing according to claim 20 or 21.
24. An absorbent pad according to any one of claims 1 to 18 or a wound dressing according to claim 20 or 21, for use in absorbing fluid discharged from a physiological target site, and/or for use in stemming a slow of fluid discharged from a physiological target site.