WO2023199022A1

WO2023199022A1 - Plaster component and infusion device

Info

Publication number: WO2023199022A1
Application number: PCT/GB2023/050821
Authority: WO
Inventors: Lisa JAUNET VAN KOOTEN; Jesper Erichsen
Original assignee: Convatec Ltd
Current assignee: Convatec Ltd
Priority date: 2022-04-11
Filing date: 2023-03-29
Publication date: 2023-10-19
Anticipated expiration: 2024-10-11
Also published as: GB202205298D0

Abstract

A plaster component for fixing an infusion device to a skin surface of a patient, an infusion device for subcutaneous infusion of a therapeutic agent comprising the plaster component, and a method of applying the plaster component to a skin surface of a patient, the plaster component comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient.

Description

PLASTER COMPONENT AND INFUSION DEVICE

TECHNICAL FIELD

The invention relates to infusion devices, plaster components of infusion devices, and associated methods. Particularly, though not exclusively, the invention relates to plaster components and infusion devices for infusing a therapeutic agent, for example insulin, to patients, for example those living with diabetes.

BACKGROUND

For patients with diabetes, insulin therapy is often an important part of their treatment, helping to regulate blood sugar levels and store excess glucose for energy. One mode of delivering insulin is an infusion pump, sometimes called an insulin pump, which delivers controlled doses of insulin throughout the day. An infusion pump can be used to deliver insulin to a patient continuously (basal dose), on demand (bolus dose) or at scheduled intervals. This mode is known as continuous subcutaneous insulin infusion (CSII) therapy.

Infusion pump systems for CSII therapy may be worn by the patient. The systems typically include a combined infusion pump and reservoir for containing an insulin drug, for example human insulin or analogue insulin, and an insulin infusion set. The infusion set may include a cannula (for example, a polymeric catheter or metal needle) for insertion subcutaneously into the patient and flexible tubing for fluidly connecting the cannula to the reservoir. Once the cannula is inserted into the patient, it may remain in place for a period of time, i.e. days, to allow for continuous delivery of the insulin drug.

The infusion set will also include a plaster component (an adhesive patch), which in simple form may be an adhesive layer for fixating the infusion set to the patient’s skin. The plaster component will include an adhesive, for example Pressure-Sensitive Adhesive (PSA) or Silicone Soft-skin Adhesive (SSA), as described in US2009/0012473, an acrylic adhesive, urethane-based adhesive, an epoxy adhesive, a cyanoacrylate adhesive or hydrocolloid adhesive. A backing layer or cover film may be used to temporarily cover a face of the plaster component prior to use. While problems relating to the infusion set have been well investigated and addressed in recent years, there remains little understanding and few solutions to address problems relating to the infusion site. Problems relating to teh infusion site include pain, bleeding, infection, skin irritation, erythema, lipohypertrophy and lipoatrophy. Problems at the infusion sit may lead to fibrosis, a build-up of scar tissue at the injection site, which is thought to be caused by repeated injections in an area causing inflammation. In turn, this affecst insulin absorption and effect, increases the risk of hypoglycaemia, as well as having a cosmetic impact on patients. All these problems can result in the skin area being unsuitable for further infusion. They may also deter patients from continuing to use their infusion pumps, resulting in poorer patient outcomes.

WO2021/119360 discloses an infusion site treatment device for prevention of scars.

It is an object of embodiments of the invention to provide an improved infusion device and/or at least mitigate one or more problems associated with known arrangements.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient.

According to another aspect of the invention there is provided an infusion device for subcutaneous infusion of a therapeutic agent, the infusion device comprising: a hub part, a plaster component to fasten the hub part onto a patient' s skin, and a cannula or needle extending through the plaster component, the plaster component comprising a first portion of elastic material and a second portion of non-elastic material, and an adhesive for securing the non-elastic portion to the skin surface of the patient. According to another aspect of the invention there is provided a method of applying a plaster component to a skin surface of a patient, the method comprising: adhering a first portion of non-elastic material to the skin surface; stretching a second portion of elastic material away from the first portion at a non-perpendicular angle to the skin surface; and adhering a third portion of non-elastic material to the skin surface, thereby causing a change in the tension of the skin surface.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the elastic material has sufficient elasticity that, when the second portion is secured to the skin surface, the first portion resiliently contracts, and the second portion is pulled parallel to the skin surface, and the plaster component thereby applies a compressive strain to the skin surface of at least 15%, or at least 20%.

Advantageously, the plaster component thereby causes the skin to contract by at least 15%, or at least 20%. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the second portion of non-elastic material comprises at least 3 subportions, wherein the first portion is positioned radially inwardly of the sub-portions, and wherein each sub-portion is joined to the first portion along an edge of the subportion; and wherein the second portion of non-elastic material surrounds the first portion of elastic material.

Advantageously, the at least 3 sub-portions of the second portion will be pulled radially outwards to stretch the plaster component outwardly. When the plaster component is adhered to the skin, the first portion of elastic material will contract back towards its original size and state, causing the patient’s skin to be pulled radially inwardly. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the second portion of non-elastic material comprises a first subportion and a second sub-portion, and the first and second sub-portions adjoin opposite sides of the first portion of elastic material; and wherein the first portion comprises an adhesive material.

Advantageously, following a first step, where a first sub-portion of non-elastic material is adhered to an area of skin, the second sub-portion is secured to the skin surface. The elastic material resiliently contracts, and the sub-portions attached to the skin pull towards each other, parallel to the skin surface. The plaster component thereby applies a compressive strain to the skin. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring. Further, after application of the plaster component to the patient’s skin, an infusion set may be adjoined to the plaster component. The adhesive portions may adhere to the base of an infusion set. An improved connection between an infusion set and the patient is provided, thereby providing an improved infusion device.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the second portion of non-elastic material surrounds the first portion of elastic material; and wherein the first portion comprises an adhesive material.

Advantageously, the second portion of non-elastic material will be pulled radially outwards to stretch the plaster component outwardly. When the plaster component is adhered to the skin, the first portion of elastic material will contract back towards its original size and state, causing the patient’s skin to be pulled radially inwardly. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring. Further, after application of the plaster component to the patient’s skin, an infusion set may be adjoined to the plaster component. The adhesive portions may adhere to the base of an infusion set. An improved connection between an infusion set and the patient is provided, thereby providing an improved infusion device.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the second portion of non-elastic material comprises at least 3 subportions, wherein the first portion is positioned radially inwardly of the sub-portions, and wherein each sub-portion is joined to the first portion along an edge of the subportion; and wherein the first portion comprises an adhesive material.

Advantageously, the at least 3 sub-portions of the second portion will be pulled radially outwards to stretch the plaster component outwardly. When the plaster component is adhered to the skin, the first portion of elastic material will contract back towards its original size and state, causing the patient’s skin to be pulled radially inwardly. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring. Further, after application of the plaster component to the patient’s skin, an infusion set may be adjoined to the plaster component. The adhesive portions may adhere to the base of an infusion set. An improved connection between an infusion set and the patient is provided, thereby providing an improved infusion device.

According to another aspect of the invention there is provided a plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient, wherein the first portion is resiliently contractable; and wherein the plaster component is configured to apply a compressive strain to the skin surface of at least 15%.

Advantageously, the plaster component thereby causes the skin to contract by at least 15%. Such a compressive strain will effectively result in a tension offloading on the skin, helping to prevent or reduce the problems associated with fibrosis and scarring.

According to another aspect of the invention a method of applying a plaster component to a skin surface of a patient, the method comprising: adhering a first portion of non-elastic material to the skin surface; stretching a second portion of elastic material away from the first portion at a non-perpendicular angle to the skin surface; and adhering a third portion of non-elastic material to the skin surface, thereby causing a change in the tension of the skin surface, wherein the first portion and third portion of non-elastic material surround the second portion of elastic material.

Advantageously, when the plaster component is adhered to the skin, the second portion of elastic material will contract (radially inwardly from a top view of the plaster component) back towards its original size and state. That action will cause the patient’s skin to be pulled radially inwardly accordingly. The change in tension of the skin surface may be advantageous in preventing or reducing fibrosis caused by multiple injections in the same area of tissue.

According to another aspect of the invention method of applying a plaster component to a skin surface of a patient, the method comprising: adhering a first portion of non-elastic material to the skin surface; stretching a second portion of elastic material away from the first portion at a non-perpendicular angle to the skin surface; and adhering a third portion of non-elastic material to the skin surface, thereby causing a change in the tension of the skin surface, wherein the second portion comprises an adhesive material.

Advantageously, the change in tension of the skin surface may be advantageous in preventing or reducing fibrosis caused by multiple injections in the same area of tissue. Further, after application of the plaster component to the patient’s skin, an infusion set may be adjoined to the plaster component. The adhesive portions may adhere to the base of an infusion set. An improved connection between an infusion set and the patient is provided, thereby providing an improved infusion device. With these arrangements, there is provided an improved connection between an infusion hub and the patient, and thereby an improved infusion device is provided.

The arrangements provide a device that is relatively straightforward, cost effective and easier to manufacture compared to some known arrangements.

The device is able to apply a compressive strain to the skin area in the region of the injection site while the infusion device is in use. Such a compressive strain will effectively result in a tension offloading on the skin. This will help to prevent or reduce the above-mentioned problems associated with fibrosis and scarring.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures, in which:

Figure 1 is a side view of a device being applied to a skin surface;

Figure 2 is a side view of the device of Figure 1 immediately after application to the skin surface;

Figure 3 is a side view of the device of Figure 1 after the device has contracted;

Figure 4 is a perspective view of a device;

Figure 5 is a perspective view of a further device;

Figure 6 is a cross sectional view of an infusion set; and

Figure 7 is a schematic view of an infusion device.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention have particular application for use with infusion pump systems such as an infusion pump for delivery of a therapeutic agent, the infusion pump comprising a fluid pump and a reservoir, and an infusion set having a cannula and tubing for connecting the cannula to the reservoir. However, other applications are contemplated, for example catheter access ports and alternative infusion pump systems such as patch pumps, which have no tubing. Embodiments of the invention may be used in closed loop systems. In certain embodiments, the infusion pump may be an insulin pump for CSII therapy and the therapeutic agent may be an insulin drug, for example human insulin or analogue insulin. Embodiments of the invention are intended for delivering insulin to a patient at a single infusion site over an extended period of time, i.e. at least four days.

Infusion devices and infusion sets will first be described with reference to Figures 6 and 7. Figure 6 shows a device 110 having a base 112 that is securable to the skin at an infusion site 114, by an adhesive patch (known as a plaster) 116, to maintain a cannula 118 within the sub-dermal tissue of a patient. The base 112 further has a port 120 for receiving the cannula 118. The base 112 is configured for attachment to an infusion cap 122 for delivering a therapeutic agent to the cannula 118 and, subsequently, into the infusion site 114. The therapeutic agent may be insulin or an insulin solution.

Together, the base 112 and the cap 122 provide an infusion hub, which serves as a fluid connector between the cannula 118 and a length of tubing 124. To effect and maintain attachment of the cap 122 to the base 112, the base 112 may have a rim 126 extending about its periphery that is configured to engage a cooperating rim 128 extending about the periphery of the infusion cap 122. The base 112 may include a self-sealing septum 130 disposed in or over the port 120.

The cannula 118 is a substantially tubular member for insertion in, and delivering the therapeutic agent to, the infusion site 114. A proximal end 118a of the cannula 118 is fluidly connected to a source of the therapeutic agent, for example a reservoir in an infusion pump system, via the tubing 124. An opposing, distal end 118b of the cannula 118 is positioned in the infusion site 114, extending to a desired depth to deliver the therapeutic agent. As the skilled person will appreciate, each of the base 112, the cannula 118, the infusion cap, and the tubing 124, in part provide a fluid pathway between the source of the therapeutic agent and the infusion site 114. The device 110 may also comprise an insertion needle, for example when the cannula 118 is a soft, polymeric catheter. To this end, the device 110 may be configured to be applied to the infusion site 114 using an inserter device. Inserter devices, which are sometimes called inserters or injectors, are used commonly in the medical field for inserting medical devices subcutaneously into a patient. Infusion sets, infusions hubs and inserter devices suitable for use in embodiments of the invention are known in the art, and examples are disclosed in earlier patent applications, including W02007/092210, WO2010/112521 , US755173, US5176662, US5257980 and WO98/9856693, the contents of which are incorporated herein by reference.

Figure 7 illustrates an infusion device 1100 including components of an infusion pump system. The device 1100 includes the device 110 described above with reference to Figure 6, including the base 112 and infusion cap 122, together forming the infusion hub, the cannula 118 and the tubing 124. The infusion hub, the cannula 118 and the tubing 124 together form an infusion set. The device 1100 further includes a combined infusion pump 1142 and reservoir 1144 for containing the therapeutic agent. A fluid pathway is provided from the reservoir 1144 to the infusion site 114, for conveying the therapeutic agent. The fluid pathway extends from the reservoir 1144 to the tubing 124, through the tubing 124, from the tubing 124 to infusion cap 122, through the infusion cap 122, from the infusion cap 122 to the base 112, through the base 112, from the base 112 to the cannula 118 and through the cannula 118.

As mentioned above, an adhesive patch (known as a plaster) 116 is used to secure a device 110 (or an infusion hub) to the skin at an infusion site 114. Figures 1-3 illustrate an example of a device 100 for fixing an infusion device (not shown) to a skin surface 10 of a patient. Such a device may be used in place of the above-mentioned adhesive patch 116 in an infusion set and in an infusion device.

Figures 1-4 illustrate the plaster component 100, including a portion 2 of elastic material and a portion 4 of non-elastic, adhesive material. All portions are generally planar and adjoin edges to form an overall generally planar plaster component. This is represented schematically in the view of Figure 4.

The join between portions may achieved by mechanical or chemical bonding. In this case, there is both a physical linkage between the portions and a chemical bond between the portions.

In this example, the portion 4 of non-elastic material includes two sub-components 4a, 4b for securing to the skin surface 10 of the patient. The sub-components are both pieces of non-elastic material, which in this case is acrylic sheet. The acrylic sheet has an adhesive element, which ensures that the plaster component fixedly adheres to both the hub part that will adjoin on one face of the plaster, and to the patient’s skin on the other face of the plaster. Other materials suitable for the portion of non-elastic material include woven and non-woven fabric.

The first and second sub-portions 4a, 4b adjoin opposite edges of the portion 2 of elastic material. In this case the elastic material is a corrugated sheet that has a spring deformation to resist stretching. The sheet is formed of corrugated copper. It could alternatively be a corrugated other metal or polymer, or other material having spring deformation properties. Alternatively it could be a non-corrugated material that exhibits resilience to a tensile force (stretching). Alternatively it could be a spring having a bias, i.e. a spring deformation in order to resist stretching.

Figures 1-3 show the sequential steps that may be followed to apply the plaster component 100 to the patient’s skin 10. As shown in Figure 1 , in a first step, a first sub-portion 4a of non-elastic material is adhered to an area of skin.

As shown in Figure 2, the second sub-portion 4b of non-elastic material is pulled away from the first portion 4a, thereby stretching the elastic material. As shown in Figure 3, the second sub-portion 4b of non-elastic material is adhered to a further area of skin (while maintaining the elastic material in the stretched position).

The elastic material 2 has sufficient elasticity that, when the second sub-portion 4b is secured to the skin surface, the elastic material resiliently contracts, and the subportions attached to the skin pull towards each other (in the direction of the arrows), parallel to the skin surface. The plaster component thereby applies a compressive strain to the skin. The compressive strain on the skin is at least 0.15 (i.e. the plaster component causes the skin to contract by 15%). More aptly, the compressive strain is at least 0.2 (the plaster component causes the skin to contract by 20%).

Looking at it another way, the plaster component would compress the skin with a compressive strain of at least 0.1 N/m.

In this description, it will be understood that the term “non-elastic” is a material that substantially does not generally stretch, having sufficient rigidity such that when adhered to the skin, the material remains joined and proximal to the skin. The material should not be able to be pulled out of shape when adhered to a surface.

In terms of the dimensions of the plaster component, compared to a standard size of plaster, for a standard infusion device, the plaster component is approximately 20% larger than a standard plaster, in terms of the width dimension from an outer edge of the first sub-portion to the outer edge of the second sub-portion, to account for the shrinkage in size when the elastic portion contracts after application to the skin.

After application of the plaster component to the patient’s skin, an infusion set may be adjoined to the plaster component. In this example the plaster component has adhesive portions that will adhere to the base of an infusion set. Optionally, removable cover layers may be used to protect the outer surfaces of the adhesive parts, which may be removed before use. In light of the above, a method of applying a plaster component to a skin surface of a patient includes adhering a first portion of non-elastic material to the skin surface, stretching a second portion of elastic material away from the first portion at a nonperpendicular angle to the skin surface, and adhering a third portion of non-elastic material to the skin surface, thereby causing a change in the tension of the skin surface.

The change in tension of the skin surface may be advantageous in preventing or reducing fibrosis caused by multiple injections in the same area of tissue.

Figure 5 shows another example of a plaster component 200, including a portion 202 of elastic material and a portion 204 of non-elastic, adhesive material.

The plaster component 200 is generally similar to the plaster component 100 of the above example of Figure 1 . The plaster component 200 is generally planar. However, the portion 204 of non-elastic material surrounds the portion 202 of elastic material. As such, there is a central portion of elastic material, which in this example is silicone. Alternatively, the first portion may be a naturally occurring polymer of isoprene, or neoprene, a synthetic polymer of 2-chloro-1 ,3-butadiene.

There is a radially outer or surrounding area of non-elastic material, which in this example is acrylic. The inner portion 202 is substantially circular over its planar surface dimension. The outer portion 204 is substantially annular over its planar surface dimension. The portions are joined by a chemical bonding. In this case, the silicone inner portion overlaps the surrounding acrylic outer portion by e.g. 1 to 3 mm, to ensure a bond of appropriate strength.

In use, the outer portion 204 will be pulled radially outwardly to stretch the plaster component radially outwardly. Then, the outer portion will be adhered to a patient’s skin. In this sense, the non-elastic material of the outer portion 204 does have some level of elasticity, to enable the portion 204 to expand (along with the expansion of the inner portion 202). An important factor in this example is that the outer portion has sufficient rigidity such that when adhered to the skin, the material remains joined and proximal to the skin.

So, when the plaster component is adhered to the skin, the inner portion of elastic material will contract (radially inwardly from a top view of the plaster component) back towards its original size and state. That action will cause the patient’s skin to be pulled radially inwardly accordingly.

The sequential steps that may be followed to apply the plaster component 200 to the patient’s skin 10 may be generally similar to the steps described above in relation to Figures 1-3. However, rather than a one-dimensional stretch being applied to the elastic material, the elastic material may be stretched in multiple directions, i.e. radially outwards from a central point. Upon application to the patient’s skin, the inner portion will tend to contract back to its original size, thereby applying a compressive strain to the skin surface.

It is envisioned that after application of the plaster component to the skin, the infusion set will be applied to the plaster component with the needle or cannula positioned at a location of a central point of the inner, elastic portion.

Figure 8 shows a further example of a plaster component 300, including an inner portion 302 of elastic material, and portions 304 of non-elastic, adhesive material. The portions 304 are sub-divided into sub-portions 304I-4.

This example is generally similar to the plaster component 200 described above. However, the portion 304 of non-elastic material surrounding the portion 302 of elastic material 302 is sub-divided into discrete and separate sub-portions. The elastic portion 302 is circular in this example. The portions are joined by chemical bond along an edge thereof. That is, for each sub-portion of non-elastic material, one edge is bonded to the outer edge of the inner portion 302 such that the four outer sub-portions generally surround the inner portion. The sub-portions are positioned at equal spacing to each other, and opposite to one other sub-portion.

In use, the sub-portions of the outer portion 304 will be pulled radially outwards to stretch the plaster component outwardly. Then, the sub-portions will be adhered to a patient’s skin.

When the plaster component is adhered to the skin, the inner portion 302 of elastic material will contract back towards its original size and state. This will cause the patient’s skin to be pulled radially inwardly.

Figure 9 shows a yet further example of a plaster component 400, including an inner portion 402 of elastic material, and portions 404 of non-elastic, adhesive material. The plaster component 400 is very similar to the plaster component 300, except that the portions 404 are sub-divided into eight sub-portions.

It will be understood that any of the above-described devices will be useable as a component of an infusion set and an infusion device. It is considered that the infusion set will be positioned over the plaster component such that the needle or cannula will pierce the elastic material and enter the skin surface. Aptly the needle or cannula will pierce the material at approximately the central point. The forces applied to the skin will be distributed approximately evenly around the needle/cannula area.

An infusion device may include a hub part, a plaster component to fasten the hub part onto a patient' s skin, and a cannula or needle extending through the plaster component. The plaster component may be any of the plaster components 100, 200, 300, 400 described above. The arrangement provides a particularly straight forward design with minimal parts for allowing a compressive strain or tension offloading to be applied to a skin area during infusion of a medicament.

A method of applying an infusion device to a skin surface of a patient includes applying a plaster component (any of those described above) to a skin surface of a patient, connecting an infusion set over the plaster component, and extending a cannula or needle through the plaster component and into the skin of the patient.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. A plaster component for fixing an infusion device to a skin surface of a patient, comprising: a first portion of elastic material; and a second portion of substantially non-elastic, adhesive material, for securing to the skin surface of the patient.

2. A plaster component as claimed in claim 1 , wherein the elastic material has sufficient elasticity that, when the second portion is secured to the skin surface, the first portion resiliently contracts, and the second portion is pulled parallel to the skin surface, and the plaster component thereby applies a compressive strain to the skin surface of at least 15%, or at least 20%.

3. A plaster component as claimed in claim 1 or 2 wherein the plaster component is configured to apply a compressive strain of at least 0.1 N/m.

4. A plaster component as claimed in any preceding claim, wherein the second portion of non-elastic material comprises a first sub-portion and a second sub-portion, and the first and second sub-portions adjoin opposite sides of the first portion of elastic material.

5. A plaster component as claimed in claim 1-3, wherein the second portion of non- elastic material comprises at least 3 sub-portions, wherein the first portion is positioned radially inwardly of the sub-portions, and wherein each sub-portion is joined to the first portion along an edge of the sub-portion.

6. A plaster component as claimed in claim 4, wherein the first portion comprises a corrugated sheet or spring having a bias to resist stretching.

7. A plaster component as claimed in any of claims 1-3, wherein the second portion of non-elastic material surrounds the first portion of elastic material.

8. A plaster component as claimed in any preceding claim, wherein the second portion comprises acrylic.

9. A plaster component as claimed in any of claims 1-7, wherein the second portion comprises a woven or non-woven fabric.

10. A plaster component as claimed in any preceding claim, wherein the first portion comprises an adhesive material.

11. A plaster component as claimed in claim 10 wherein the first portion comprises silicone.

12. A plaster component as claimed in claim 10 wherein the first portion comprises a naturally occurring polymer of isoprene, or neoprene, a synthetic polymer of 2-chloro- 1 ,3-butadiene.

13. A plaster component as claimed in claim 1 , wherein the first portion is resiliently contractable; and wherein the plaster component is configured to apply a compressive strain to the skin surface of at least 15%.

14. An infusion device for subcutaneous infusion of a therapeutic agent, the infusion device comprising: a hub part, a plaster component to fasten the hub part onto a patient' s skin, and a cannula or needle extending through the plaster component, the plaster component comprising a first portion of elastic material and a second portion of non-elastic material, and an adhesive for securing the non-elastic portion to a skin surface of the patient.

15. A method of applying a plaster component to a skin surface of a patient, the method comprising: adhering a first portion of non-elastic material to the skin surface; stretching a second portion of elastic material away from the first portion at a non-perpendicular angle to the skin surface; and adhering a third portion of non-elastic material to the skin surface, thereby causing a change in tension of the skin surface.