WO2010142955A1

WO2010142955A1 - Actuating apparatus

Info

Publication number: WO2010142955A1
Application number: PCT/GB2010/001135
Authority: WO
Inventors: Simon Frank Rich
Original assignee: Polarseal Tapes And Conversions
Priority date: 2009-06-09
Filing date: 2010-06-09
Publication date: 2010-12-16
Also published as: GB0909991D0; GB2470938B; GB2470938A

Abstract

An apparatus (2) for retaining an item in contact with a surface under pressure is provided, the apparatus comprising a chamber (4) having a flexible wall the flexible wall being moveable between an extended position and a retracted position; retaining means (18) for retaining the apparatus on the surface such that the flexible wall is in contact with the surface; and biasing means (6) disposed within the chamber and urging the flexible wall into the extended position. The apparatus is particularly suitable for the delivery or dosing of a drug or medicament to the surface of the skin of a subject.

Description

ACTUATING APPARATUS

The present invention relates to an apparatus for holding an item in contact with a surface and allowing pressure to be applied thereto. The apparatus is of particular use in applying and holding items on the skin of a subject, including but not limited to dressings, retaining medical devices and the delivery of drugs through the skin of the subject.

There are many requirements for holding a item or device in contact with a surface and applying pressure thereto, for example to increase and maintain an intimate contact between the item or device and the surface. A number of such requirements arise in the medical field, in particular in the need to apply and retain items and devices in contact with the skin of a subject.

For example, many systems for monitoring or analysing a subject require devices, such as sensors, electrodes and transducers, to be held in close contact with the skin of the subject. Such devices may need to be held in close contact with the surface of the skin of the subject. Alternatively, such devices may need to penetrate the skin and be held in position.

Further, it is increasingly the case that drugs are being formulated for delivery to the subject through the skin, as an alternative to oral administration or administration by injection or intravenously. Examples of such drugs are those that are to be administered to the subject over an extended period of time, including slow-release formulations, and those which are to be delivered to target a localised region adjacent the skin of the subject, such as a joint. Examples of such drugs include those for the treatment of inflammation, pain and conditions such as diabetes. It is known and very common practice to apply items and devices to the skin of a subject by means of an adhesive. In particular, the use of adhesive tape and dressings is very commonplace. While such tapes and dressings are very adaptable and find very widespread use, they are limited in their ability to provide a close contact between the item or device being held and the skin. In particular, adhesive tape, adhesive dressings and the like will not apply a constant pressure to the item or device or the skin of the subject.

Accordingly, there is a need for an improved means for retaining an item or device in contact with a surface, such as the skin of a subject, in particular a means whereby a constant pressure can be applied to the surface, such as the skin.

According to the present invention, there is provided an apparatus for retaining an item in contact with a surface under pressure, the apparatus comprising: a chamber having a flexible wall the flexible wall being moveable between a extended position and a retracted position; retaining means for retaining the apparatus on the surface such that the flexible wall is in contact with the surface; and biasing means disposed within the chamber and urging the flexible wall into the extended position.

In use, the apparatus is applied to the surface, to which it is held by the retaining means, with the flexible wall in contact with the item or device to be held and to which pressure is to be applied. The biasing means urge the flexible wall into the extended position against the item or device, thereby applying a pressure thereto. The retaining means should be such that the apparatus is held firmly on the surface against the action of the biasing means, which may tend to lift the apparatus from the surface. The apparatus comprises a chamber having a flexible wall for disposing in contact with the surface. The flexible wall is moveable between a retracted position, in which the apparatus applies little or no pressure to the surface, and an extended position, in which the flexible wall applies pressure to the surface under the action of the biasing means. The chamber may be of any suitable shape or form. In a preferred arrangement, the chamber is generally circular in plan view, providing a generally circular region of contact between the flexible wall and the surface to which the apparatus is attached.

In one simple and preferred embodiment, the chamber is formed as a cell between two opposing layers of material, one layer forming the flexible wall. The second layer may be rigid. More preferably, both layers are flexible, in use one layer forming the flexible wall urged into contact with the surface, the second layer forming a second flexible wall that is urged away from the surface by the biasing means. Materials suitable for forming the flexible wall and, if appropriate, the second flexible wall of the chamber are known in the art and include plastics. Medical grade plastics suitable for use in medical devices and for direct contact with the skin of subjects are commercially available. Examples of suitable plastic materials include films of polyolefins, in particular polyethylene and polypropylene, polyurethanes, polyesters, VA and PVA.

The apparatus further comprises means to retain the apparatus on the surface. The apparatus is held on the surface with the flexible wall in contact with the item or device to which pressure is to be applied. As noted above, the biasing means urges the flexible wall into the extended position towards the surface, thereby applying pressure to the surface. The retaining means should resist the action of the biasing means to lift or raise the apparatus out of contact with the surface. Any suitable form of retaining means may be employed. In one preferred embodiment, the retaining means comprises an adhesive applied to a surface of the apparatus that is in contact with the surface, when in use. Suitable adhesives are known in the art and are commercially available, in particular adhesives for use in contact with the skin of a subject. The adhesive should provide sufficient adhesion to the surface, in particular the skin of a subject, to resist the action of the biasing means, as mentioned above.

In one embodiment, the retaining means is formed by a portion of the flexible wall extending beyond the perimeter of the chamber, with the said portion being provided with means to secure the apparatus to the surface. In a preferred embodiment, the surface of the flexible wall is provided with a suitable adhesive to contact and adhere to the surface, once the apparatus is applied.

The apparatus comprises biasing means disposed within the chamber. The biasing means act on the flexible wall to urge it into the extended position and into contact with the surface. Any suitable biasing means may be employed, the properties of which are selected to apply the appropriate force to the flexible wall, so as to apply the desired pressure to the surface, when the apparatus is in use. The biasing means preferably acts to tauten the flexible wall when urging the flexible wall into the extended position. In this way, the flexible wall is, tautened together with any member that may be in contact with or applied to the flexible wall. In one preferred arrangement, the biasing means comprises a resilient material disposed within the chamber to bear directly or indirectly upon the inner surface of the flexible wall. The resilient material may be of any suitable shape or form. Preferably, the resilient material is provided with a cavity therein that is arranged to overlie and contact the flexible wall. In this way, the action of the resilient material when in the extended position is to stretch the flexible wall across the cavity. Any suitable resilient material may be employed, with its properties being selected as hereinbefore described. In a particularly preferred embodiment, the resilient material is a foam. Suitable foam materials, in particular open cell foams, include polyurethane foams, are known in the art and are available commercially.

The resilient material disposed within the chamber may have any suitable shape. In one preferred embodiment, the resilient material is in the form of a disc disposed within the chamber to bear upon the inner surface of the flexible wall, most preferably in contact with the inner surface of the flexible wall. In an alternative preferred arrangement, the resilient material is in the form of a ring or torus, having a cavity in the centre thereof in contact with the flexible wall. The item or device to be acted upon by the apparatus is preferably arranged to be in line with the cavity in the centre of the resilient material. By having the resilient material formed as a tube or torus and arranged to have the cavity therein extend across the flexible wall, it has been found that the action of the bias of the resilient material is to tauten the flexible wall across the cavity, which in turn improves the contact between the item or device and the surface to which the apparatus is applied.

In a preferred embodiment, the apparatus further comprises means to hold the flexible wall in the retracted position against the action of the biasing means. Any suitable means may be employed. In a preferred embodiment, the chamber is provided so as to be gas-tight, with the means to hold the flexible wall in the retracted position being provided by a reduced gas pressure or partial vacuum in the chamber, thereby relying upon atmospheric pressure to hold the flexible wall in the retracted position. The chamber may be provided with a suitable opening to allow a gas, such as air, to enter the chamber and release the flexible wall to move into the extended position. The chamber is provided with a suitable closure means to cover the opening, which may be released by any suitable means when it is required to activate the apparatus. This is most preferably done once the apparatus has been applied to and is retained on the surface. Alternatively, the chamber may be provided with at least a portion of its wall that may be easily punctured, once the apparatus has been installed on the surface, to thereby allow air to enter the chamber.

In one preferred embodiment, the chamber is formed with a second flexible wall, as described hereinbefore, the second flexible wall having an opening therein covered by a removable tab of material. Upon removing the tab, the opening is revealed, allowing air to enter the chamber and the flexible walls to move apart under the action of the biasing means, most preferably a resilient foam. Alternatively, the second flexible wall of the chamber may be punctured with any suitable means to form an opening and allow air to enter the chamber, releasing the flexible wall.

In use, the apparatus is applied to the surface, such as the skin of a subject, the apparatus either containing or being placed over the item or device to be retained, such that the flexible wall bears upon the item or device, applying pressure to it. The apparatus may comprise further means to hold part of the item or device, such as a clip or the like to hold cables, tubes and lines.

The apparatus of the present invention may be used to hold and apply pressure to a wide range of devices and items in contact with a surface, in particular a wide range of devices and items needed to be brought into close contact with the skin of a subject. Examples include electrodes, sensors, such as temperature sensors, electrical sensors and the like, as well as means for delivering a drug or a dose to the skin of a subject. In this respect, references to 'dose' refer to a composition or formulation that is required to be administered to the skin of a subject, in particular in predetermined amounts or at a predetermined rate, and includes both drugs and other non-regulated medicaments or treatments, such as solutions for use in diagnostic methods, for example allergy testing, skin sensitising and desensitising, and the like.

In one embodiment, the apparatus further comprises a drug or dose delivery means disposed such that, when the apparatus is in use, the drug or dose delivery means is between the flexible wall and the surface, the drug or dose delivery means preferably being mounted on the flexible wall. Suitable drug or dose delivery means include reservoirs or other means for holding a drug or dose for delivery to the skin of a subject. The drug or dose delivery means may thus comprise a material impregnated with the drug or dose to be delivered, from which it may be released onto and into the skin of the subject. Alternatively, the drug or dose delivery means may comprise a reservoir of drug or dose retained by a permeable member, through which the drug or dose will pass, preferably at a predetermined or controlled rate, to the skin of the subject.

In a further aspect, the present invention provides a drug or dose delivery device comprising an apparatus as described hereinbefore.

Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which:

Figure 1 is a plan view of an apparatus according to one embodiment of the present invention;

Figure 2 is a cross-sectional view of the apparatus of Figure 1 in the retracted condition along the line Il - II;

Figure 3 is a cross-sectional view of the apparatus of Figure 2 in the extended condition;

Figure 4 is a cross-sectional view of the apparatus in the condition shown in Figure 3 and applied to the skin of a subject over a drug delivery device;

Figure 5 is a plan view of an apparatus according to a second embodiment of the present invention;

Figure 6 is a cross-sectional view of the apparatus of Figure 5 in the retracted condition along the line Il - II;

Figure 7 is a cross-sectional view of the apparatus of Figure 6 in the extended condition; and

Figure 8 is a cross-sectional view of the apparatus in the condition shown in Figure 7 and applied to the skin of a subject over a drug delivery device. Referring to Figure 1 , there is shown a plan view of an apparatus according to the present invention and generally indicated as 2. The apparatus 2 comprises a generally circular chamber 4 having a resilient foam pad 6 disposed therein. A retaining ring 8 extends around the chamber.

The apparatus 2 of Figure 1 is shown in cross-section in Figure 2, from which the general construction of the chamber 4 and the retaining ring 8 may be seen. Thus, the apparatus 2 comprises a first flexible layer 10, the central portion 12 of which forms a lower flexible wall of the chamber 4 (as viewed in the figures). The outer portion 14 of the first flexible layer 10 forms the lower surface 16 of the retaining ring 8. A layer of adhesive 18 extends across the lower surface 16 of the retaining ring 8.

The apparatus 2 further comprises a second flexible layer 20, the central portion 22 of which forms an upper flexible wall of the chamber 4 (as viewed in the figures). The outer portion 24 of the second flexible layer 20 forms the upper surface of the retaining ring 8. The respective outer portions 14 and 24 of the first and second flexible layers 10, 20 are bonded together to provide an air-tight seal around the chamber 4, for example by a suitable adhesive, welding, heat sealing or the like.

The first and second flexible layers are formed from a suitable grade film. The adhesive layer 18 comprises a suitable grade adhesive. Suitable materials are known in the art and available commercially.

The central portion 22 of the second flexible layer 20 is provided with an opening 30 and a removable tab 32 extending over the opening 30, so as to prevent air entering the chamber 4.

As an alternative, the second flexible layer 20 may be without an opening, the user puncturing the wall of the chamber 4, most typically by piercing the central portion 22 of the second flexible layer 20 with a suitable means, to allow air to enter the chamber. The resilient pad 6 is formed from a disc of foam and is in contact with the inner surfaces of the upper and lower flexible walls of the chamber 4. It will be understood that shapes and forms other than a disc may also be employed to similar effect.

The apparatus 2 is shown in Figure 2 in the retracted condition. In this condition, the chamber 4 is partially evacuated, causing atmospheric pressure to bear upon the lower flexible wall of the chamber, compressing the resilient foam pad, as shown. Removal of the tab 32 from the upper flexible wall of the chamber 4 allows air to enter the chamber, inflating the resilient foam pad 6, urging the lower flexible wall of the chamber 4 downwards, as viewed in the figures. The apparatus is shown with the tab 32 removed and the flexible walls in the extended position in Figure 3. In this way, the lower flexible wall is urged under pressure into contact with the surface to which the apparatus is adhered, as shown in Figure 4.

Referring to Figure 4, the apparatus 2 is shown in place on the surface of the skin 40 of a subject. A drug or dose delivery device 42 is disposed on the skin. The drug or dose delivery device may be any suitable means for delivering a drug or dose to the skin of the subject. The device shown in Figure 4 is a simple absorbent pad, impregnated with a drug or dose. Other drug or dose delivery devices will be apparent to the person skilled in the art. The apparatus is disposed over the drug or dose delivery device 42 with the lower flexible wall of the chamber in contact with the drug delivery device. The apparatus is secured to the surface by the adhesive layer 18 on the lower side of the retaining ring 8. Once applied to the skin 40 in this manner, the apparatus is activated, to allow air to enter the chamber 4, causing the resilient foam pad 6 to urge the lower flexible wall of the chamber against the drug or dose delivery device 42, thereby applying pressure to the drug or dose delivery device and urging it into contact with the skin.

Referring to Figures 5 to 8, there is shown a second embodiment of the apparatus of the present invention. The apparatus, generally indicated as 102, is of the same general construction as that shown in Figures 1 to 4 and described above. Accordingly, the components common to the first and second embodiments have been indicated using the same reference numerals. The second embodiment differs from the first embodiment in the following way.

Referring to Figures 5 to 8, the apparatus 102 comprises a resilient foam pad 106 in the form of a ring having a cavity 107 therein. The pad 106 is formed from foam, as described above, and is arranged to present the cavity 107 to the central portion 12 of the first flexible layer 10, as shown more clearly in Figure 6.

With the apparatus 102 in its extended position, as shown in Figures 7 and 8, the central portion 12 of the first flexible wall 10 is tautened across the cavity 107 of the ring 106 by the biasing action of the resilient foam. As shown in Figure 8, the apparatus 102 is applied over the drug or dose delivery device 42 such that the cavity 107 in the resilient ring 106 is aligned with and overlies the drug or dose delivery device, at least in part. In this way, the action of the resilient ring 106 is to pull the central portion 12 of the first flexible layer 10 taut across the cavity 107, thereby improving engagement of the drug delivery device with the surface of the skin of the subject.

The first flexible layer 10 may be provided with a suitable drug delivery or dosing member, which may be attached directly to the first flexible layer 10, as shown in Figure 8. The drug or dose delivery member may be adhered directly to the first flexible layer 10. Alternatively, or in addition thereto, the apparatus may further comprise a layer of web or other porous material adhered to the first flexible layer 10 and extending over the drug delivery or dosing member. If the resilient member is arranged to tauten the first flexible layer 10 as it extends the apparatus, any web or other material attached to the first flexible layer will be stretched. This will, in turn, improve the delivery of the drug to the skin of the subject. The apparatus may be used to apply and retain other devices, such as sensors, electrodes, transducers, thermometers and the like, to the skin of a subject in like manner.

The pressure applied by the apparatus may be controlled by appropriate selection of the materials of construction and the size and shape of the components, in particular those forming and contained within the chamber. More particularly, the action of the apparatus in applying pressure to an item or device may be controlled by the appropriate selection of the size, shape and material of the biasing member within the cavity, in particular the size, shape and material of the resilient foam pad of the specific embodiments. In this way, the apparatus may be used to retain and apply pressure to a wide range of items and devices, in particular a wide range of medical devices and implements that are required to be held under pressure to the skin of a subject.

Claims

1. An apparatus for retaining an item in contact with a surface under pressure, the apparatus comprising: a chamber having a flexible wall, the flexible wall being moveable between an extended position and a retracted position; retaining means for retaining the apparatus on the surface such that the flexible wall is in contact with the surface; and biasing means disposed within the chamber and urging the flexible wall into the extended position.

2. The apparatus according to claim 1 , wherein the chamber is generally circular in plan view.

3. The apparatus according to either of claims 1 or 2, wherein the chamber is formed between a first layer of material and a second layer of material, the first layer forming the flexible wall.

4. The apparatus according to claim 3, wherein the second layer is rigid.

5. The apparatus according to claim 3, wherein the second layer is flexible.

6. The apparatus according to claim 5, wherein the first and second layers are of the same material.

7. The apparatus according to any preceding claim, wherein the retaining means comprises a portion of the flexible wall extending beyond the perimeter of the chamber, means being provided to attach the said portion to the surface when in use.

8. The apparatus according to any preceding claim, wherein the retaining means comprises a layer of adhesive applied to a surface of the apparatus in contact with the surface when in use.

9. The apparatus according to any preceding claim, wherein the biasing means acts to tauten the flexible wall when in the extended position.

10. The apparatus according to any preceding claim, wherein the biasing means comprises a resilient material.

11.The apparatus according to claim 10, wherein the resilient material is a foam.

12. The apparatus according to claim 11 , wherein the foam is an open-cell foam.

13. The apparatus according to any of claims 9 to 1 1 , wherein the resilient material is in the form of a disc.

14. The apparatus according to any of claims 9 to 11 , wherein the resilient material is in the form of a ring, the ring being arranged such that the flexible wall extends across the cavity in the ring.

15. The apparatus according to any preceding claim, further comprising means to hold the flexible wall in the retracted position against the action of the biasing means.

16. The apparatus according to claim 15, wherein the said means comprises a partial vacuum within the chamber.

17. The apparatus according to claim 16, wherein the chamber is provided with an opening to allow the ingress of gas into the chamber and a releasable closure for closing the opening.

18. The apparatus according to claim 16, wherein the wall of the chamber is provided with at least a portion that may be easily punctured, to allow gas to enter the chamber.

19. The apparatus according to any preceding claim, further comprising means to hold a cable, tube, line or the like.

20. The apparatus according to any preceding claim, further comprising a drug or dose delivery means, in use the drug or dose delivery means being disposed between the flexible wall and the surface.

21.A drug or dose delivery device comprising a drug or dose retained in a means for delivering the drug or dose to the surface of the skin of a subject and an apparatus as claimed in any of claims 1 to 19.