Wound dressing, ingredient delivery device and IV hold-down, and method relating to same

An adhesive device used as a wound dressing, ingredient delivery device or IV hold-down in which inadvertent edge release of these devices along the periphery of the polymeric film layer is minimized when the handling layer, which is adhered to the polymeric film layer, is removed after application of the polymeric film layer to the patient.

BACKGROUND OF THE INVENTION

The present invention relates to adhesive devices used as wound dressings, ingredient delivery devices and IV hold-downs.

Wound dressing and IV hold-downs in particular comprise a layer of polymeric film having an adhesive layer on one side thereof, which is protected during storage and handling by a release liner. United States Patent Publication 2002/0107466 A1 discloses such devices which also have a handling member adhered to the non-adhesive coated side of the polymeric film by means of a pressure sensitive adhesive. The pressure sensitive adhesive used between the handle and the polymeric film is less aggressive than the pressure sensitive adhesive used on the underside of the polymeric film, such that once the polymeric film is applied to a patient's skin or mucosa, the handle can be peeled away without peeling the polymeric film away from the patient's skin.

Experience has shown that regardless of differences in adhesive strength between the skin or mucosa adhesive and the handle adhesive, there is a tendency for the edge of the polymeric film to lift away from the user's skin or mucosa when the handle member is peeled away from the back of the polymeric film. This same tendency is observed in the wound dressing disclosed in U.S. Pat. No. 6,169,224, where the handling member is sealed to the polymeric film by a heat activated adhesive.

SUMMARY OF THE INVENTION

In the various aspects of the present invention, inadvertent edge release caused by peeling the handle member away from the polymeric film can be minimized by the following methods or combinations thereof:1. minimizing the electrostatic charge buildup in the localized area of the polymeric film beneath the handle, as the handle is peeled away from the film; and/or2. decreasing the mechanical advantage of the handle relative to the thin film.

In various different preferred aspects of the invention, either or both of these are accomplished by:1. interrupting the continuity of contact between the handle and the underlying surface of the polymeric film to which the handle is adhered, said adherence either being due to electrostatic attraction or to the use of an adhesive layer on the underside of the handle;2. placing an anti-static ingredient in one of, the adhesive coating on the underside of the polymeric film, or in an anti-static coating on the upper or lower surface of the polymeric film itself, with the anti-static agent preferably being located in an adhesive layer on the underside of the polymeric film;3. removing at least a portion of the periphery of the handle layer, or of the adhesive layer on the underside of the handle if one issued, so that it does not extend to the periphery of the polymeric film layer upon which the handle layer resides; and/or4. reducing the surface area of the adhesive coating disposed on the periphery of handle.

In another aspect of the invention, an inwardly-directed thumb tab, oriented at an obtuse angle with respect to the edge of the handle in the direction in which the handle is pulled, is provided to facilitate peeling of the handle away from the polymeric film. Such a thumb tab enhances the ease with which the handle is peeled away from the polymeric film. The thumb tab starts the peeling at such an angle that the tendency of the handle to lift the underlying polymeric film away from the patient's skin or mucosa is minimized.

These and other objects, features and advantages of the invention will be more fully understood and appreciated by reference to the written specification and appended drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Introduction

The term “dressing” as used herein is to be understood to include wound dressings, IV hold-downs and transdermal, dermal, transmucosal and mucosal delivery systems. The various preferred embodiments disclosed herein have many components or similar components in common, which are described in this Introduction using numbers which are common to all embodiments. The differing embodiments, and the similar elements thereof, are distinguished by adding the letters a-j.

In the various preferred embodiments, the basic elements of a device in accordance with the present invention comprise a handle10having either an adhesive coating20on the undersurface thereof or being electrostatically adhered to an underlying polymeric film30, and preferably having an inwardly-projecting thumb tab11(FIGS. 1-3). Handle10is applied to the non-adhesive coated surface of a polymeric film30having a pressure sensitive adhesive layer40on the undersurface thereof. Adhesive layer40is protected during handling and storage by a release liner50having a silicone coating layer51. In use, release liner50is removed from the assembled polymeric film30and handle10, and handle10is then used to manipulate the polymeric film and place it on the patient. Once the polymeric film as been applied to the patient, the user grasps inwardly-projecting thumb tab11on handle10and peels handle10away from the applied polymeric film30.

Inadvertent edge release caused by removal of the handle10is minimized by any one or any combination of the following:1. the angle at which thumb tab11projects from handle10;2. by minimizing the build up of localized electrostatic charge on the polyurethane film as the handle is removed; and/or3. decreasing the mechanical advantage of handle10relative to film30.

Objects 2 and 3 are accomplished by any one or any combination of the following:1. interrupting the continuity of contact between the handle and the underlying non-adhesively coated surface of the polymeric film;2. placing an anti-static ingredient in one of, the adhesive coating on the underside of the polymeric film, or in an anti-static coating on the upper or lower surface of the polymeric film itself, with the anti-static agent preferably being located in the adhesive layer on the underside of the polymeric film;3. removing at least a portion of the periphery of the handle layer, or of the adhesive layer on the underside of the handle, if one issued, so that it does not extend to the periphery of the polymeric film layer upon which the handle layer resides; and/or4. reducing the surface area of the adhesive coating disposed on the periphery of handle.

Handle10is preferably made of a stiffer and generally thicker material than that of polymeric film30. Typical of such materials are plastic or paper material. Useable plastics include polyesters, polycarbonates, PVC's, polyurethanes, polyethylene vinyl acetates, polyester copolymers, polyethylenes, and polypropylenes. In the preferred embodiment a silicone coated paper50, with a silicone coating51on the upper surface thereof, is used.

InFIG. 2, the undersurface of each handle10is coated with an optional adhesive layer20, preferably a pressure sensitive adhesive which is moderately aggressive with respect to polymeric film30, but which does not adhere or adheres less aggressively to either the silicone coating51on release liner50or to human skin. In this way, a user can readily fold back an end portion of release liner50to expose an end of handle10, and the exposed end can then be used to peel film30away from release liner50. The adhesive of layer20is “moderately aggressive” in that handle10remains attached to polymeric film30when it is peeled away from release liner50, and while it is being handled and applied to the patient's skin. However, adhesive20is less aggressive with respect to its adhesion to polymeric film30, than is the adhesion of layer40on the undersurface of polymeric film30toward human skin or mucosa. As a result, handle10can be peeled away from polymeric film30, once film30is applied to the patient.

One type of adhesive which we have found useful for layer20on the undersurface of handle10is a low tack removable acrylate-based adhesive with a peel adhesive level of approximately three ounces. Other useful adhesives include, but are not limited to, silicone, urethane, synthetic rubber and natural rubber. Adhesives of this type can be formulated to have essentially no or very little adhesion to the human skin or to the silicone coating51on the release liner50, but still adhere firmly but releasably to film30.

Alternatively, handle10can be electrostatically adhered to polymeric film30, rather than through the use of an adhesive layer on the undersurface of handle10. In such an embodiment, handle layers10and20as shown in the drawings comprise a layer of non-conductive material10, e.g., a layer of polymeric film, and a layer of conductive material20(rather than a layer of adhesive). For example, a layer of aluminum20might be vapor deposited onto non-conductive polymeric film layer10.

Optionally, conductive layer20may be disposed between two layers of non-conductive polymeric films, rather than having a single layer on only one side. However, only one non-conductive layer20is required, and handle10-20can be applied to polymeric film30with either conductive layer20applied directly against film30, or with non-conductive layer10lying against film30. The static change generated during handling of the materials in manufacture is sufficient to electrostatically bond handle10-20to film30. An optional corona treatment may be used as a way to increase the electrostatic surface adhesion of the polymeric film, but it is not necessary.

A second electrostatic charge is created during the application process which enhances the electrostatic bond between handle10-20to polymeric film30. This second electrostatic charge is generated when release liner50is peeled away from the adhesive layer40on the undersurface of film30. Though not wishing to be bound by theory, when these two materials are separated, a positive charge will accumulate on the surface of the polyurethane and a negative charge on the release liner. Since two oppositely charged surfaces will attract each other, the positive static charge of polymeric film30is then attracted to the electron rich, negatively charged, conductive material20. Therefore, this additional statically attractive force adds to the retention of handle10-20to polymeric film30, and tends to remain until the user applies the system to the patient, at which time the system is grounded, thereby removing or at least diminishing the electrostatic attractive force.

Polymeric film30is preferably comprised of any breathable and waterproof material. In the preferred embodiment, a polymeric film on the order of from about 0.5 to about 4 mils (0.0005 to 0.004 inches) is preferred. The film is preferably very flexible, allowing it to conform readily to the user's skin or mucosa. The film must have sufficient strength to afford resistance to damage in handling and in use. It also preferably allows the passage of oxygen, thereby allowing the skin or mucosa to breathe. The polymeric film material preferably is a polyurethane film such as a Pebax® film (MediFilm 810, 2 mils, Mylan). Additionally, copolymers of polyethylene and vinyl acetate are also preferable.

The adhesive layer40may be any adhesive that bonds well to skin or mucosa. Preferably, a pressure sensitive adhesive is used. A type of adhesive found useful for adhesive layer40is a permanent acrylate-based pressure sensitive adhesive designed for skin, with a peel adhesion level of approximately 50 ounces. Other useful adhesives include, but are not limited to, silicone, urethane, synthetic rubber and natural rubber. Such adhesives can be formulated to adhere releasably to the silicone coated surface51of a release liner50. At the same time, they can be formulated to adhere firmly to the patient's skin or mucosa such that polymeric film30will not peel away unless someone intends to do so. For example, one can use an acrylate derivative adhesive such as copolymers of alkyl acrylate/vinyl acetate containing —OH or/and —COOH functional groups, or hydrophobic styrenic rubber polymer or PIB containing 1 to 20% hydroattractants such as PVP, PVA, and cellulose derivatives such as Duro-Tak 87-2516 (National Starch), and PIB containing 20% Kollidong® CL-M (BASF).

The entire assembly of handle10, adhesive layer20, polymeric film30and adhesive layer40is releasably adhered to a release liner50. Release liner50may be comprised of any material that will releasably adhere adhesive layer40. However, in the preferred embodiment, release liner50is a paper material with a silicone coating51on the top surface thereof.

The very properties of polymeric film30which make it desirable in use make it difficult to handle in application. The drape and flexibility properties of polymeric film30may cause it to fold over onto itself and self-adhere relatively easily when one is trying to apply the system to the user's skin. The thicker handle10disclosed in the preferred embodiment reduces these shortcomings and makes the systems relatively easy to apply without fouling polymeric film30. However, the structural characteristics of the stiffer and generally thicker material of handle10which aid in the application is compromised when a cut line13is made to handle10(FIG. 1). Cut line13, which aids the applicator in the removal of handle10, compromises the structural integrity of handle10and allows the polymeric film30to fold over and adhere to itself.

Edge release typically occurs with these systems when handle10is removed from polymeric film layer30. The generally thicker material of handle10creates a lever arm out of handle10when handle10is being peeled off of film30. This lever arm created by handle10acts to pry up film30from the patient's skin. If this force is great enough the edge of film30can separate from the patient's skin (e.g., edge release occurs). In general, as the stiffness of the material of handle10increases, the less flexible it becomes. The less flexible the handle becomes, the longer the lever arm becomes and this in turn creates higher forces which act upon film layer30causing more significant edge release. In addition, it is believed that as handle10is removed from polymeric film layer30, it causes an electrostatic buildup in film layer30, which contributes to the tendency of the edge of film30to release from and be pulled away from a patient's skin or mucosa. Therefore, the properties that make handle30useful, namely its stiffness, also create edge release.

The Angled Thumb Tab

Tab11is provided on handle10to minimize the tendency of film30to fold over at cut line13, as well as aid in the removal of handle10. Inwardly-projecting thumb tab11includes a distal portion12. Preferably, the underside of thumb tab11is not coated with adhesive. In the preferred embodiment, the leading edge A of thumb tab11is disposed at an angle greater than 90 degrees with respect to the edge of the handle in the direction “B” in which the handle is pulled, and distal portion12extends beyond cut line13into window15of handle10. Preferably, the angle is between about 120° and about 150°, and most preferably about 135°. This placement of distal portion12provides more support for polymeric film30and handle10and it is therefore less likely that polymeric film30will fold at cut line13. However, this is merely the preferred embodiment and tab10may also be disposed outwardly. Similarly, it is preferably that cut line13extends between the edges of handle10at between about 130° and about 150°, most preferably about 135°, with respect to the direction in which handle10will be initially peeled away from film30. This also helps prevent film30from buckling across the cut through the handle.

As described above, edge release typically occurs with these systems when handle10is removed from polymeric film layer30. Tab11minimizes this tendency by reducing the mechanical advantage that handle10has over polymeric film30when handle10is being peeled off. The mechanical advantage is reduced by the angle at which thumb tab11projects from handle10and subsequently, the angle at which handle10is removed from polymeric film30.

Interrupting the Continuity of Contact Between the, Handle and the Polymeric Film

In addition to the mechanical advantages of thumb tab11, edge release can also be minimized by interrupting the continuity of contact between the adhesive coated surface of handle10and the underlying non-adhesively coated surface of the polymeric film30, at least in the vicinity of at least a portion of the edge of handle10. Although not wishing to be bound by theory, it is believed that this interruption helps to minimize edge release in three ways:1. less contact area means handle10can be removed more easily;2. the mechanical advantage of the handle relative to the film30edge is reduced; and3. localized electrostatic build up when handle10is peeled away from film30is reduced.

Interrupting the contact between the adhesive layer20of handle10and film30reduces the contact area. We have found it helpful to reduce the contact area by from about 10% to about 70%, preferably about 10% to about 50%, and most preferably from about 10% to about 30%, as compared to the contact area without such interruptions in continuity. If a greater reduction in contact area is desired, a more aggressive adhesive can be used in adhesive layer20.

One technique for interrupting the adhesive layer of the handle and the non-adhesively coated surface of polymeric film30is to texture handle10, at least at adhesive layer20on handle10which faces and is adhered to polymeric film30. Preferably, this texturing is done by piercing slots16through handle10and adhesive coating layer20(FIGS. 1-6). Other techniques include placing pin holes through handle10(FIGS. 7,8); knurling handle10(FIGS. 9,10); embossing or debossing handle10; printing adhesive layer20in a pattern (FIG. 11); and employing a handle material having a relatively rough surface facing polymeric film layer30. Alternatively, the polymeric film30may be textured on the side facing handle10(FIG. 12). Preferably, the texturing is done in such a way as to break the adhesive coating layer itself, as distinguished from merely making it irregular in shape (see e.g.,FIGS. 2,4and8).

As depicted inFIG. 1, a first embodiment is shown utilizing a plurality of piercing slots16completely surrounding and angularly disposed with respect to window15. The slots16may be pierced from the either side. However, in the preferred embodiment the slots are pierced from the top surface and through adhesive layer20on handle10as shown inFIG. 2.

In response to the piercing action, material of handle10at the pierced location is deflected toward polymeric film layer30resulting in a raised portion17of slot16(FIG. 2). Film30tends to bridge over raised portions17of slots16, creating a “tunnel” at which film30is separated from handle10. Raised portion17thereby effectively reduces the area of contact between film30and adhesive layer20of handle10. This reduces the adhesive retention of handle10to polymeric film30.

Also when handle10is removed from polymeric film30an atmospheric venting effect21occurs in the tunneling area (FIG. 4). This venting effect enhances the ease of removal of the handle. The result is less inadvertent edge release.

Additionally, raised portion17which is in contact with polymeric film30provides a conductive pathway between polymeric film30and handle10. This pathway interrupts the continuity of contact between the adhesive coated surface20of handle10and the underlying non-adhesively coated surface of polymeric film30thereby minimizing the electrostatic buildup of localized electrostatic charge on the polyurethane film during the removal of handle10. This minimization of electrostatic build up contributes towards the reduction in edge release.

FIG. 5shows a second embodiment including slots16awhich are parallel to window15aalong its sides, and angularly disposed with respect to the top and bottom surface. In this configuration, after the release liner50ais removed, atmospheric venting effect21aagain occurs (FIG. 6).

A third embodiment is shown inFIG. 7and is similar to the first two embodiments except that it utilizes a puncture or pinhole to interrupt the continuity between the handle10band the polymeric film30b. As shown inFIG. 8, pinholes16bminimize edge release by reducing the adhesion of handle10bto the polymeric film30band also providing a conductive pathway between polymeric film30and handle10in order to minimize electrostatic buildup as described above.

A fourth embodiment using a knurled pattern is depicted inFIG. 9. The knurled pattern may take any geometrical shape and be either embossed or debossed on handle10c. Additionally, the pattern may be varied thereby increasing or decreasing the contact area to accommodate the application requirements. Unique to this embodiment is the feature that the knurls16cdo not puncture handle10c. Instead, the reduction in adhesion is accomplished through the bottom of knurls16cresiding directly on polymeric film layer30cand therefore reducing the adhesive contact surface of polymeric film30c, as shown ifFIG. 10. However, this is not meant to be limiting and knurls16cmay puncture handle10cif required. Embossing or debossing handles10is similar to knurling, though the raised portion would probably be larger in area than the knurl projections.

Additionally, a fifth embodiment is shown inFIG. 11. This embodiment reduces the adhesion between handle10dand polymeric film layer30dby patterning the adhesive layer. As described above, the pattern may be varied thereby increasing or decreasing the contact area according to the specific requirements of the application.

Still further, it is possible to accomplish this reduction in continuity through the use of a rough surface or handle10, facing polymeric film layer30. This can be done, for example, through the use of a rough or non-smooth paper for handle10.

FIG. 12shows a sixth embodiment which uses a polymeric film layer30ehaving at least a textured upper surface to reduce the continuity of contact between handle10eand polymeric film30e. The pattern may take any geometrical shape and be either embossed or debossed on polymeric film layer30e. Additionally, as described above, the pattern may be varied thereby increasing or decreasing the contact area to accommodate the application requirements. The patterning of polymeric film layer30emay be accomplished mechanically or chemically.

While the embodiments described above are wound dressings or IV hold-down devices, the various aspects of the present invention are also applicable to devices designed to deliver active ingredients to or through the dermal or mucosal layers. Such delivery systems typically deliver the active via a gel modulated system, membrane modulated system, or an adhesive modulated system. All of the embodiments ofFIGS. 1-19can be made to be ingredient delivery devices by incorporating an active ingredient into adhesive layer40-40j, for example.

The delivery system depicted inFIG. 14includes a breathable and waterproof polymeric film30g. Layered to a first side of film30gis adhesive layer40g. Adhered to adhesive layer40gof film30gis an active ingredient containing island60g. Island60gcomprises a thin or ultra thin polymeric backing film62g. Layered to backing film62gis an active ingredient layer63gthat may or may not be incorporated into an adhesive.

Incorporating an Anti-Static Ingredient

Edge release can also be minimized by utilizing an anti-static coating to minimize the electrostatic buildup that occurs when handle10is removed. A seventh embodiment using an anti-static coating61is shown inFIG. 13. The anti-static coating layer61on polymeric film layer30facts to minimize the electrostatic buildup of localized electrostatic charge on polyurethane film30fduring the removal of the handle10f. The minimization of electrostatic build up contributes towards the reduction in edge release. Alternatively, or in addition, anti-static material may be incorporated onto the lower surface of polyurethane film30for into adhesive layer40fof polyurethane film30f.

Removing a Portion of Handle or Adhesive at the Periphery

Removing a portion of handle10, or its underlying adhesive layer20, from over at least a portion of the edge area of film layer30helps to minimize edge release. Although not wishing to be bound by theory, it is believed that this is accomplished in three ways:1. less adhesive contact area means handle10can be removed more easily;2. reducing the ability of handle10to act as a lifting lever relative to film30, at least when a portion of the handle per se is removed; and3. minimizing the localized electrostatic build up at the periphery of film30when handle10is peeled from film30, by moving the periphery of handle10away from the edge of film30.

One way to move at least a portion of the edge of said handle away from the periphery of said polymeric film is to pattern the handle layer with a scalloped pattern as shown inFIGS. 16 and 17. In this embodiment, the scalloping extends around the entire perimeter of handle10. The scalloped edge reduces the mechanical advantage of handle10primarily in two ways. The first is by reducing the surface area of adhesive coating20disposed on the periphery of handle10, and the second is by reducing the ability of handle10to act as a lever. In the first mode, a portion of the periphery of handle10is removed resulting in scalloped edge15. Simultaneous to this removal of a portion of handle10is the removal of a corresponding portion of adhesive coating20attached thereto. This removal of adhesive20on the periphery of handle10reduces the upward force exerted on the periphery of polymeric film30by adhesive coating20during its removal. Reducing the upward force exerted on the periphery of polymeric film30reduces edge lift. In the second mode, scalloped edge15reduces the ability of the generally thicker material of handle10to act as a lever arm.

When the peripheral interaction between adhesive layer20and polymeric film30is removed, the localized electrostatic buildup on film30is also reduced. This is because the interaction between adhesive layer20and film layer30, during their separation, causes the electrostatic buildup. The removal of a portion of the peripheral edge of handle10, and subsequently adhesive layer20, or the removal of some of the adhesive at the edges of handle10minimizes the electrostatic buildup on the peripheral edge of polymeric film30by removing this interaction and therefore, reduces edge lift.

The scalloped edge (15) of handle10is depicted inFIG. 16as having a wave like or sinusoidal like pattern, leaving projecting portions16extending to the edge of film layer30. Other geometrical forms may be used which reduce the interaction between the periphery of handle10and the periphery of film30. While a handle could be made that simply does not extend to the edge of film layer30, thereby reducing edge lift, the scalloped pattern has the advantage of having end portions16that extend to the edge of film30. End portions16act to support thin film30and keep it from folding over onto itself during application. Therefore, scalloped edge15retains the benefits of a handle layer (e.g., ease of application) while minimizing the negative effects of a handle layer (e.g., edge lift).

In theFIG. 18embodiment, the edge portion of handle10along two opposite sides thereof, preferably the longest sides, have been substantially removed as a continuous, uninterrupted strip. This leaves the longest edge portions31of polymeric film but retains a portion of handle10along two other sides which extends to the film periphery sides to support film30during application. Preferably, only the central portion of the edge of handle10is removed, such that end or corner portions11of handle10extend out to the edges or corners to give stability. TheFIG. 19embodiment is similar to theFIG. 18version, but also incorporates a window of removed handle material which is centrally located on the dressing, leaving the central portion32of film30also exposed.

Although only a few preferred embodiments have been shown and described it is envisioned that there are numerous geometrical patterns that may used. Additionally, there are supplementary methods which can be combined with the various edge geometries for reducing the edge lift even further. For example, the preferred embodiment may include additional features such as texturing handle10, texturing adhesive layer20, texturing polymeric film layer30and/or using an anti-static ingredient in one of, the adhesive coating on the underside of the polymeric film, or on the upper or lower surface of the polymeric film itself. Additionally, texturing may be done by piercing slots, placing pin holes, knurling, embossing or debossing, or creating a relatively rough surface on handle10.

CONCLUSION

The embodiments described above minimize the problem of edge release which typically occurs in adhesive devices used as wound dressings, ingredient delivery devices and IV hold-downs. Of course it is understood that the above are preferred embodiments only, and that various changes and alterations can be made without departing from the spirit and scope of the invention as set forth in the appended claims, as interpreted in accordance with the principles of patent law.