U.S. patent application number 17/667659 was filed with the patent office on 2022-08-25 for wound care device having fluid transfer and adhesive properties.
The applicant listed for this patent is Milliken & Company. Invention is credited to Cristina M. Acevedo, Matthew I. Foote, Laura Maher, Rajib Mondal, Gregory A. Satterfield.
Application Number | 20220265893 17/667659 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220265893 |
Kind Code |
A1 |
Maher; Laura ; et
al. |
August 25, 2022 |
WOUND CARE DEVICE HAVING FLUID TRANSFER AND ADHESIVE PROPERTIES
Abstract
This disclosure relates to a wound care device which contains
capillary force one-way pumps that are capable of transporting
fluid, such as wound exudate, away from a wound site to the
opposite side of the wound care device, which functions as a
segregated fluid reservoir. This fluid transport mechanism
generally aids in reducing wound maceration by removing excess
wound fluid and the protease enzymes and infectious bacteria
contained within the wound fluid. The wound care device performs
this function, often times for multiple days, without the loss of
the physical integrity of the wound care device. In addition to
providing a uni-directional fluid transport mechanism, the wound
care device contains a perforated adhesive layer.
Inventors: |
Maher; Laura; (Campobello,
SC) ; Foote; Matthew I.; (Spartanburg, SC) ;
Satterfield; Gregory A.; (Pelzer, SC) ; Mondal;
Rajib; (Greer, SC) ; Acevedo; Cristina M.;
(Greer, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Milliken & Company |
Spartanburg |
SC |
US |
|
|
Appl. No.: |
17/667659 |
Filed: |
February 9, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16415051 |
May 17, 2019 |
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17667659 |
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62674091 |
May 21, 2018 |
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International
Class: |
A61L 15/58 20060101
A61L015/58; A61F 13/00 20060101 A61F013/00; A61L 15/22 20060101
A61L015/22; A61L 15/44 20060101 A61L015/44; A61F 13/02 20060101
A61F013/02; A61L 15/18 20060101 A61L015/18; A61L 15/24 20060101
A61L015/24 |
Claims
1. A method for managing moisture at a wound site comprising the
steps of: (a) providing a wound care device comprising: a fabric
having a wound contact surface and a wound fluid reservoir surface,
wherein said wound contact surface is comprised primarily of
hydrophobic fiber and said wound fluid reservoir surface is
comprised primarily of hydrophilic fiber, said hydrophobic and
hydrophilic fibers being intermeshed together in a jersey knit
construction; wherein said wound contact surface is coated with a
layer of apertured silicone adhesive; and wherein said wound care
device transports wound fluid uni-directionally from said wound
contact surface to said wound fluid reservoir surface upon exposure
to a wound; (b) placing said wound contact surface of said wound
care device in contact with said wound site; and (c) allowing said
wound care device to transport wound fluid uni-directionally from
said wound contact surface to said wound fluid reservoir
surface.
2. The method of claim 1, wherein said wound contact surface is
further coated with a composition comprising at least one silver
ion-containing compound.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and is a divisional of
U.S. patent application Ser. No. 16/415,051, entitled "Wound Care
Device Having Fluid Transfer and Adhesive Properties," which was
filed on May 17, 2019, which claims priority to U.S. Provisional
Patent Application No. 62/674,091, entitled "Wound Care Device
Having Fluid Transfer and Adhesive Properties" which was filed on
May 21, 2018, both of which are entirely incorporated by reference
herein.
TECHNICAL FIELD
[0002] This disclosure relates to a wound care device which
contains capillary force one-way pumps that are capable of
transporting fluid, such as wound exudate, away from a wound site
to the opposite side of the wound care device, which functions as a
segregated fluid reservoir. This fluid transport mechanism
generally aids in reducing wound maceration by removing excess
wound fluid and the protease enzymes and infectious bacteria
contained within the wound fluid. The wound care device performs
this function, often times for multiple days, without the loss of
the physical integrity of the wound care device. In addition to
providing a uni-directional fluid transport mechanism, the wound
care device contains a perforated adhesive layer.
[0003] In one aspect, the wound care device is comprised of a knit
construction characterized in that polyester fiber is primarily
present on the wound contact surface and nylon fiber is primarily
present on the fluid reservoir surface. A third fiber, such as an
elastomeric polyurethane known by the tradename Lycra.RTM., may
also be included in order to provide some amount of elasticity to
the wound care device. The wound care device provides a one way
directional flow of fluid away from the wound and into the nylon
fluid reservoir. The perforated silicone gel adhesive layer, which
is designed for direct contact with the wound, functions to prevent
the wound care device from sticking to the wound.
BACKGROUND
[0004] In the medical field, and in the area of wound care
particularly, it is well-established that many factors, including
the amount of moisture present at a wound site, affects how quickly
a wound will heal. Generally speaking, having an excessive amount
of moisture present at a wound site, especially when combined with
the warm environment provided by the body, leads to undesirable
bacteria growth and production of protease enzymes in the wound.
Such growth can cause further damage to healthy cells and delay the
healing process. However, insufficient moisture at the wound site
can cause eschar (scab) formation and scarring and may cause the
wound care device, or medical dressing, to adhere to the wound. If
the dressing adheres to the wound, subsequent removal of the
dressing may cause undue discomfort to the patient as well as
disrupt newly granulated tissue. Infection of the wound may also be
compounded when a medical dressing is removed and portions of the
dressing remain behind in the wound itself, particularly if the
dressing is already colonized with pathogenic microbes. Thus, it is
important that the dressing maintains its physical integrity when
exposed to stress, such as during removal from the wound, in order
to prevent additional complications and delays in healing.
[0005] Absorptive materials such as gauzes, hydrogels, swellable
fibers, foams, woven textiles and the like have been incorporated
into wound care devices for the purpose of controlling the wound
moisture content. Fluids are generally absorbed by these types of
materials by reversible capillary action or osmosis rather than by
a one-way directional flow created by an inventive two-sided wound
care device.
[0006] For example, U.S. Pat. No. 5,009,652 to Morgan et al.
discloses a disposable laminated medical sponge that contains a
thin film which is impervious to fluids and infectious agents. The
medical sponge is designed to prevent the seepage of bodily fluids
from one side of the sponge to the opposite side, since such
seepage provides risk of infection for health-care workers having
direct contact with patients.
[0007] U.S. Pat. No. 6,194,332 to Rock et al. discloses an
antimicrobial composite fabric having a first inner fabric layer
and a second outer fabric layer. The inner fabric layer may be
comprised of polyester, acrylic or nylon fiber which has been
rendered hydrophilic, such as by mechanical or chemical treatment.
The hydrophilic inner fabric layer enables the transport of sweat
from the inner fabric layer to the outer fabric layer. The fibers
in the outer layer of the fabric may be blended with antimicrobial
fibers in order to reduce the proliferation of bacteria in this
layer. The fabric may be formed into a garment which provides
reduced body odor. U.S. Pat. No. 6,602,811 to Rock et al. discloses
a similar antimicrobial composite fabric, except that the second
outer fabric layer also may be treated with an antimicrobial
paste.
[0008] US Patent Application Publication No. 2004/0001880 to Bowler
et al. discloses the use of gel forming fibers such as sodium
carboxymethycellulose which can be incorporated into wound
dressings. Silver ions may be incorporated into the fibers by
combining them in a solution with a solvent prior to fiber
formation. The dressing may be used as part of a larger dressing or
a layer in a multi-layered dressing and need not be in direct
contact with the wound.
[0009] The wound care device of the present invention takes
advantage of a unique textile fabric construction which effectively
isolates fluid away from the wound, along with a silicone gel
adhesive layer which aids in preventing the wound care device from
detrimentally sticking to the wound. Both of these features promote
and improve the healing process. The differentiation that exists in
a wound care device having a hydrophobic fiber on the wound contact
side of the device and hydrophilic fiber on the fluid reservoir
side of the device creates a unique one-way, directional flow of
fluid and contaminants away from the wound.
[0010] A further feature of the wound care device of the present
invention is that the device may also contain a topical coating of
an antimicrobial agent such as silver. It is known that placing
surface-available silver in contact with a wound allows the silver
to enter the wound and become absorbed by undesirable bacteria and
fungi that grow and prosper in the warm, moist environment of the
wound site. Once absorbed, the silver ions kill microbes, resulting
in treatment of infected wounds or the prevention of infection in
at-risk wounds. Methods of topically applying a silver-based
antimicrobial finish to textile substrates are described, for
example, in commonly assigned U.S. Pat. Nos. 6,584,668; 6,821,936;
and 6,946,433 and in commonly assigned U.S. patent application Ser.
Nos. 09/586,081; 09/589,179; 10/307,027; and Ser. No. 10/306,968.
All of these patents and patent applications are hereby
incorporated by reference. Details of many of these processes will
be discussed below.
[0011] The present disclosure addresses and overcomes the problems
described above. Whereas, historically, a gauze or foam medical
dressing has been applied to a wound with at least some intent on
absorbing fluids, the present disclosure describes a wound care
device capable of creating a one-way, directional flow of fluid and
contaminants away from the wound, without detrimentally causing
excessive dryness of the wound and substantial adherence of the
device to the wound. The wound care device may additionally provide
desired release of silver to the wound site for antimicrobial
efficacy and, because of its unique construction, maintains its
physical integrity when exposed to stress during ordinary use of
the wound care device.
[0012] For these reasons and others that will be described herein,
the present wound care device having unique fluid management
properties and easy release/removal from the wound represents a
useful advance over the prior art.
BRIEF SUMMARY
[0013] In one aspect, the invention relates to a wound care device
comprising: a single layer of fabric having a wound contact surface
and a wound fluid reservoir surface, wherein said wound contact
surface is comprised primarily of hydrophobic fiber and said wound
fluid reservoir surface is comprised primarily of hydrophilic
fiber, said hydrophobic and hydrophilic fibers being intermeshed
together in a jersey knit fabric construction; wherein said wound
contact surface is coated with a layer of apertured silicone
adhesive; and wherein said wound care device transports wound fluid
uni-directionally from said wound contact surface to said wound
fluid reservoir surface upon exposure to a wound.
[0014] In another aspect, the invention relates to a wound care
device comprising: a single layer of fabric having a wound contact
surface and a wound fluid reservoir surface, wherein said wound
contact surface is comprised primarily of polyester fiber and said
fluid reservoir surface is comprised primarily of nylon fiber,
wherein said polyester and nylon fibers are intermeshed together in
a jersey knit construction, wherein said wound contact surface is
coated with a layer of apertured silicone adhesive, and wherein
said wound care device transports wound fluid uni-directionally
from said wound contact surface to said wound fluid reservoir
surface upon exposure to a wound.
[0015] In a further aspect, the invention relates to a wound care
device comprising: a wound contact surface and a wound fluid
reservoir surface, wherein said wound contact surface is comprised
primarily of hydrophobic fiber and said fluid reservoir surface is
comprised primarily of hydrophilic fiber, wherein said hydrophobic
and hydrophilic fibers are intermeshed together in a jersey knit
construction, and wherein said wound care device transports wound
fluid uni-directionally from said wound contact surface to said
wound fluid reservoir surface upon exposure to a wound; wherein
said wound contact surface is coated with a composition comprising
at least one silver ion-containing compound; and wherein said wound
contact surface is further coated with a layer of apertured
silicone adhesive.
[0016] In another aspect, the invention relates to a wound care
device comprising: (a) a single layer of fabric having a wound
contact surface and a wound fluid reservoir surface, wherein said
wound contact surface is comprised primarily of hydrophobic fiber
and said wound fluid reservoir surface is comprised primarily of
hydrophilic fiber, said hydrophobic and hydrophilic fibers being
intermeshed together in a jersey knit fabric construction; wherein
said wound contact surface is coated with a layer of apertured
silicone adhesive; (b) optionally, a first hot melt adhesive layer;
(c) a fluid retentive layer; (d) optionally, a second hot melt
adhesive layer; (e) optionally, an occlusive film layer; and
wherein said wound care device transports wound fluid
uni-directionally from said wound contact surface to said wound
fluid reservoir surface upon exposure to a wound.
[0017] In yet another aspect, the invention relates to a wound care
device comprising: a single layer of fabric having a wound facing
surface and a wound fluid reservoir surface, wherein said wound
facing surface is comprised primarily of hydrophobic fiber and said
wound fluid reservoir surface is comprised primarily of hydrophilic
fiber, said hydrophobic and hydrophilic fibers being intermeshed
together in a jersey knit fabric construction; wherein said wound
facing surface is coated with a layer of apertured silicone
adhesive; and wherein said wound care device transports wound fluid
uni-directionally from said wound facing surface to said wound
fluid reservoir surface upon exposure to a wound.
[0018] In a further aspect, the invention relates to a method for
managing moisture at a wound site comprising the steps of: (a)
providing a wound care device comprising: a fabric having a wound
contact surface and a wound fluid reservoir surface, wherein said
wound contact surface is comprised primarily of hydrophobic fiber
and said wound fluid reservoir surface is comprised primarily of
hydrophilic fiber, said hydrophobic and hydrophilic fibers being
intermeshed together in a jersey knit construction; wherein said
wound contact surface is coated with a layer of apertured silicone
adhesive; and wherein said wound care device transports wound fluid
uni-directionally from said wound contact surface to said wound
fluid reservoir surface upon exposure to a wound; (b) placing said
wound contact surface of said wound care device in contact with
said wound site; and (c) allowing said wound care device to
transport wound fluid uni-directionally from said wound contact
surface to said wound fluid reservoir surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a perspective view of a wound care device
according to the invention having a fluid transport layer and an
apertured adhesive layer.
[0020] FIG. 1B is an exploded perspective view of the wound care
device depicted in FIG. 1A.
[0021] FIG. 1C is a perspective view of a wound care device
according to the invention having a fluid transport layer and an
alternative apertured adhesive layer.
[0022] FIG. 1D is a perspective view of a wound care device
according to the invention having a fluid transport layer and a
border adhesive layer.
[0023] FIG. 1E is a perspective view of another embodiment of a
wound care device according to the invention having a fluid
transport layer and a border adhesive layer and further
illustrating the adhesive layer extending beyond the other layers
of the device.
[0024] FIG. 2 is a plan view of a laid-in fabric suitable for use
as the fluid transport layer of a wound care device according to
the invention.
[0025] FIG. 3A is a plan view of an apertured polymeric film, such
as that depicted in FIGS. 1A and 1B, suitable for use as the
adhesive layer of a wound care device according to the
invention.
[0026] FIG. 3B is a side view of a trilaminate apertured polymeric
film suitable for use as the adhesive layer of a wound care device
according to the invention.
[0027] FIG. 4 is a plan view of a composite article according to
the invention showing the surface of the composite article having
the adhesive layer and the underlying fluid transport layer.
[0028] FIG. 5 is a photomicrograph at 20.times. magnification
illustrating multiple apertures in the adhesive layer of the wound
care device and the presence of fibers from the fluid transport
layer being present in those apertures according to the
invention.
[0029] FIG. 6 is a photomicrograph at 40.times. magnification
illustrating multiple apertures in the adhesive layer of the wound
care device and the presence of fibers from the fluid transport
layer being present in those apertures according to the
invention.
[0030] FIG. 7 is a photomicrograph at 80.times. magnification
illustrating a single aperture in the adhesive layer of the wound
care device and the presence of fibers from the fluid transport
layer being present in the aperture according to the invention.
[0031] FIG. 8 is a photomicrograph at 2500.times. magnification
illustrating the presence of silver-containing compounds on the
fibers of the fluid transport layer according to the invention.
[0032] FIG. 9 is a photomicrograph at 90.times. magnification of a
side view of a portion of the wound care device according to the
invention.
[0033] FIG. 10 is a photomicrograph at 100.times. magnification
illustrating the apertures in the adhesive layer of Comparative
Example 1.
[0034] FIG. 11 is a photomicrograph at 250.times. magnification
illustrating the apertures in the adhesive layer of Comparative
Example 1.
[0035] FIG. 12 is a photomicrograph at 50.times. magnification
illustrating the apertures in the adhesive layer of Comparative
Example 3.
[0036] FIG. 13 is a photomicrograph at 100.times. magnification
illustrating a single aperture in the adhesive layer of Comparative
Example 3.
[0037] FIG. 14 is a bar graph illustrating antimicrobial efficacy
of wound care devices of the present invention and Comparative
Example 1.
DETAILED DESCRIPTION
Definitions and Terms
[0038] "Hydrophilic" is defined as having a strong affinity for or
the ability to absorb water.
[0039] "Hydrophobic" is defined as lacking affinity for or the
ability to absorb water.
[0040] "Non-electrically conductive" is defined as having a
resistance in ohms per square inch of fabric of greater than about
10,000 ohms, preferably greater than about 100,000 ohms and most
preferably greater than about 1.times.10.sup.9 ohms, when measured
in accordance with AATCC Test Method 76-1978.
[0041] As utilized herein, the term "surface energy" refers to the
excess energy at the surface of a material compared to the bulk of
the material (e.g., the interior portions of the material) and is
usually expressed in terms of milliJoules per square meter
(mJ/m.sup.2). The surface energy quantifies the disruption of
intermolecular bonds that occurs when a surface is created. The
surface energy can be measured by several means including, for
example, the Fowkes method. In this method, two reference liquids
are used to first measure the dispersive component and the polar
component of the material's surface energy. The surface energy of
the material is then calculated from the measured dispersive and
polar components. In general, a surface having a higher surface
energy will exhibit a higher affinity for aqueous fluids, such as
perspiration or wound exudate.
Wound Care Device
[0042] The wound care device of the present invention is generally
intended to be used for treatment of various wounds including,
without limitation, partial thickness burns, incisions, skin
grafts, donor sites, lacerations, abrasions, Stage I-IV pressure
ulcers, vascular venous stasis, and diabetic ulcers. The wound care
device is generally comprised of: (a) a layer of fabric formed from
synthetic fibers, natural fibers, or combinations thereof, and (b)
a layer of perforated silicone gel adhesive.
[0043] Synthetic fibers comprising the fabric layer include, for
example, polyester, acrylic, polyamide, polyolefin, polyaramid,
polyurethane, regenerated cellulose (i.e., rayon), and blends
thereof. The term "polyamide" is intended to describe any
long-chain polymer having recurring amide groups (--NH--CO--) as an
integral part of the polymer chain. Examples of polyamides include
nylon 6; nylon 6, 6; nylon 1, 1; and nylon 6, 10. The term
"polyester" is intended to describe any long-chain polymer having
recurring ester groups (--C(O)--O--). Examples of polyesters
include aromatic polyesters, such as polyethylene terephthalate
(PET), polybutylene terephthalate (PBT), polytrimethylene
terephthalate (PTT), and polytriphenylene terephthalate, and
aliphatic polyesters, such as polylactic acid (PLA). "Polyolefin"
includes, for example, polypropylene, polyethylene, and
combinations thereof. "Polyaramid" includes, for example,
poly-p-phenyleneteraphthalamid (i.e., Kevlar.RTM.),
poly-m-phenyleneteraphthalamid (i.e., Nomex.RTM.), and combinations
thereof. Natural fibers include, for example, wool, cotton, flax,
and blends thereof.
[0044] The fabric may be formed from fibers or yarns of any size,
including microdenier fibers and yarns (fibers or yarns having less
than one denier per filament). The fibers or yarns may have deniers
that range from less than about 1 denier per filament to about 2000
denier per filament or more preferably, from less than about 1
denier per filament to about 500 denier per filament, or even more
preferably, from less than about 1 denier per filament to about 300
denier per filament.
[0045] Furthermore, the fabric may be partially or wholly comprised
of multi-component or bi-component fibers or yarns, which may be
splittable, or which have been partially or fully split, along
their length by chemical or mechanical action. The fabric may be
comprised of fibers such as staple fiber, filament fiber, spun
fiber, or combinations thereof.
[0046] The fabric may be of any variety, including but not limited
to, woven fabric, knitted fabric, nonwoven fabric, or combinations
thereof. The fabric may optionally be colored by a variety of
dyeing techniques, such as high temperature jet dyeing with
disperse dyes, vat dyeing, thermosol dyeing, pad dyeing, transfer
printing, screen printing, or any other technique that is common in
the art for comparable textile products. If yarns or fibers are
treated by the process of the current invention, they may be dyed
by suitable methods prior to fabric formation, such as, for
instance, by package dyeing or solution dyeing, or after fabric
formation as described above, or they may be left undyed.
[0047] Other additives may be present on and/or within the target
fabric or yarn, including antistatic agents, optical brightening
compounds, opacifiers (such as titanium dioxide), nucleating
agents, antioxidants, UV stabilizers, fillers, permanent press
finishes, softeners, lubricants, curing accelerators, adhesives,
and the like. The present fabrics may also be coated or printed or
otherwise aesthetically modified in addition to being treated with
the present antimicrobial compositions. Printing may be achieved,
for example, by screenprinting or flexographic printing
techniques.
[0048] One specific example of a knit pattern that is suitable for
making the fabric that comprises the wound care device of the
present invention is a jersey knit. A jersey knit is a circular or
flat-knit fabric made with a plain stitch in which the loops
intermesh in only one direction. As a result, the appearance of the
face and the back of the jersey fabric is wholly different. Thus,
by utilizing a jersey knit to form a fabric comprised of polyester,
nylon, and elastomeric fibers, a fabric may be constructed that is
primarily polyester-containing on one side while the opposite side
of the fabric is primarily nylon-containing. The elastomeric fiber
provides some level of stretch to the fabric, which may be useful
for some wounds that require, for example, a dressing to be wrapped
snugly around the wound site. The elastomeric fiber, in addition to
providing conformability to the wound care device, also provides
some level of softness to the device. Spandex is one non-limiting
example of an elastomeric fiber and may be known by the tradename
Lycra.RTM., which is available from INVISTA of Wichita, Kans.
[0049] Additionally, it may be generally known to those skilled in
the art that a knit polyester fabric tends to be hydrophobic, slow
to absorb liquids, and generally exhibits little or no wicking of
moisture. Since polyester is hydrophobic in nature, conventional
wisdom would lead one to choose a hydrophilic natural fiber, such
as cotton, or a hydrophilic synthetic fiber, such as nylon, as the
wound contacting side of the wound care device. However, it was
unexpectedly discovered that by placing a hydrophobic polyester
containing surface against the wound site and a hydrophilic nylon
containing surface away from the wound site, a unique one-way,
directional flow of fluid away from the wound site was
achieved.
[0050] As noted above, the fluid transport layer 106 comprises a
first surface 108 and a second surface 110. The first surface 108
of the fluid transport layer 106 has a first surface energy, and
the second surface 110 of the fluid transport layer 106 has a
second surface energy. In one embodiment, the surface energy of the
second surface 110 of the fluid transport layer 106 is greater than
the surface energy of the first surface 108 of the fluid transport
layer 106. This difference in surface energies between the two
surfaces means that the second surface 110 of the fluid transport
layer 106 exhibits a greater affinity for aqueous fluids (e.g.,
perspiration or wound exudates) than the first surface 108 of the
fluid transport layer 106. Thus, any aqueous fluids absorbed by the
fluid transport layer 106 will be transported or pumped from the
first surface 108 to the second surface 110 of the fluid transport
layer 106. This active transportation or pumping of the fluids
ensures that excess moisture does not accumulate at the interface
of fluid transport layer 106 and a fluid exuding surface, such as
the skin or an exuding wound.
[0051] When the fluid transport layer comprises first and second
surfaces having different surface energies, the difference between
the two surface energies can be of any suitable magnitude. In a
specific embodiment, the surface energy of the second surface 110
of the fluid transport layer 106 can be about 101% or more of the
surface energy of the first surface 108 of the fluid transport
layer 106. In more specific embodiments, the surface energy of the
second surface 110 can be about 102% or more, about 103% or more,
or about 104% or more of the surface energy of the first surface
108.
[0052] In a specific embodiment, the fluid transport layer 106 can
be a textile material in which the surface energy of the second
surface 110 is higher than the surface energy of the first surface
108. In order to provide the differential surface energies
described above, the fluid transport layer can also comprise a
material in which one surface has been chemically or physically
modified to yield a material having first and second surfaces
exhibiting different surface energies. For example, in one
embodiment, the fluid transport layer can be a textile material
such as those described above having a first surface that has been
chemically treated in order to lower the surface energy thereof. In
such an embodiment, the textile material can be treated, for
example, with a relatively hydrophobic fluorocarbon or silicone
(i.e., a fluorocarbon or silicone that is more hydrophobic than the
material comprising the non-treated side of the textile
material).
[0053] As shown in FIG. 2, such a construction results in a fabric
in which the technical face of the fabric is predominantly one type
of yarn 202, and the technical back presents a higher proportion of
the effect yarn(s) 204. Thus, when the yarn 202 and the effect yarn
204 have different surface energies or one is more hydrophilic than
the other, the resulting fabric will exhibit a different surface
energy on each of the two major surfaces. In a specific embodiment
of the fluid transport layer depicted in FIG. 2, the yarn(s) 202
are more hydrophilic than the effect yarn(s) 204. For example, the
yarn(s) 202 can be polyamide yarns (e.g., nylon yarns), and the
effect yarn(s) 204 can be polyester yarns. Such an embodiment of
the fluid transport layer provides a layer in which the technical
face of the fabric exhibits a higher surface energy than the
technical back of the fabric. Thus, when utilized as the fluid
transport layer of the composite article depicted in FIGS. 1A to
1E, such a fabric (i.e., the fabric depicted in FIG. 2) is disposed
so that the technical back of the fabric forms the first surface
108 of the fluid transport layer 106 and the technical face of the
fabric forms the second surface 110 of the fluid transport layer
106.
[0054] While fiber types are known to be generally hydrophilic or
hydrophobic in their natural or initial manufactured condition,
this condition can be changed with chemical and/or physical
modification to the fibers and/or textile substrates containing the
fibers. For instance, polyester fiber could be made to exhibit
hydrophilic properties via chemical and/or mechanical treatment.
Chemical treatments that may make normally hydrophobic
fibers/fabrics more hydrophilic include, for example, Visa
Endurance.RTM. fabric treatment available from Milliken &
Company of Spartanburg, S.C. Mechanical treatments that may make
normally hydrophobic fibers/fabrics more hydrophilic include, for
example, exposure to mechanical face finishing processes. Exemplary
mechanical treatments include face finishing treatments like
sanding, napping, calendaring, hydroentanglement with gas or
liquid, and the like, and combinations thereof. As a result of
these options, in one aspect of the invention, a suitable fabric
may be comprised of treated polyester fiber exhibiting hydrophilic
properties and treated polytetrafluoroethylene ("PTFE") fibers
exhibiting hydrophobic properties. In another aspect, a suitable
fabric may be comprised of fibers, such as cotton, viscose, or
lyocell, with higher hydrophilicity than nylon and treated nylon
fibers exhibiting hydrophobic properties.
[0055] The layer of perforated silicone gel adhesive is comprised
of polydimethylsiloxane (also referred to herein as "PDMS" and/or
"silicone") and its derivatives. In one aspect, the perforated
silicone gel adhesive is comprised of multiple layers. For example,
the perforated trilaminate silicone adhesive layer may be comprised
of a skin facing silicone layer, a polyurethane layer (e.g. a
polyurethane film), and an acrylic pressure sensitive adhesive
layer. In another aspect of the invention, additional adhesive
materials may be used in place of, or in combination with, the
silicone gel adhesive. Therefore, the adhesive layer of the present
invention may be comprised of materials selected from the group
consisting of natural rubber-based adhesive materials, synthetic
rubber-based adhesive materials, hydrocolloid materials, acrylate
and/or acrylic materials, polyurethane gel materials,
polydimethylsiloxane materials, and the like, and mixtures thereof.
In addition, one or more of the following types of adhesive
materials may be suitable for use as the adhesive layer of the
wound care device of the present invention:
TABLE-US-00001 TABLE A Types of Adhesive Materials Ultraviolet
and/or Visible Acrylics and/or Acrylates Indigo Visible Acrylics
and/or Acrylates Flashcure Cyanoacrylates Silicones Cyanoacrylates
Polyurethane Gel Polyurethane Synthetic Rubber Surface Insensitive
Low Odor and/or Low Bloom Toughened and/or Flexible General Purpose
Primers and/or Accelerators One-Part Heat Cure Epoxies Two-Part
Room Temperature Cure Epoxies and/or Urethanes Thermally Conductive
Compound Thermally Conductive Gel
[0056] Accordingly, any of the foregoing adhesive materials and/or
types of adhesive materials may be used alone, or in combination
with one another, as the adhesive material comprising the adhesive
layer of the wound care device of the present invention. It is also
contemplated to be within the scope of the present invention that
at least one antimicrobial agent may be included in the adhesive
material comprising the adhesive layer.
[0057] The perforations in the adhesive layer may be of any shape
and size suitable for the end-use application of the wound care
device. In one aspect, a mechanical or electronic rotary die punch
machine may be used to create the perforations in the adhesive
layer. The perforations may be created in the adhesive layer prior
to assembling the wound care device (e.g. a pre-perforated sheet of
silicone), or the perforations may be added after at least part of
the wound care device has been assembled. In the latter instance, a
needle punching apparatus may be used to needle punch the fluid
transport layer through the adhesive layer. This perforation method
may create the apertures in the adhesive layer and cause the fibers
of the fluid transport layer to be pulled through the
apertures.
[0058] The apertures forming the perforations may be of any size.
In one aspect, the apertures in the silicone layer are in the range
from about 0.1 mm to about 7 mm, or in the range from about 1.0 mm
to about 3.0 mm, or even in the range from about 1.3 mm to about
1.9 mm. The apertures may be present in the adhesive layer in any
pattern. In one aspect, the distribution of apertures is present in
a regular, uniform arrangement. In another aspect, the distribution
of apertures may be present in the adhesive layer in a non-uniform
arrangement.
[0059] In one aspect, the apertures in the adhesive silicone layer
may be in the form of "windows" or openings that are larger in
diameter than conventional apertures or small holes. In this
regard, the apertured adhesive layer may include one window (or
opening) or multiple windows (or openings) in the layer. These
larger windows or openings may be present in a uniform or
non-uniform pattern across the surface of the adhesive layer. When
one large window is present in the approximate center of the
apertured adhesive layer, the configuration may be referred to as a
"border" adhesive since adhesive material is present only around
the outer edges ("border") of the silicone adhesive layer. One
advantage of these window and/or border adhesive layers is that the
fluid transport layer, which is present immediately behind the
adhesive layer, will have increased surface contact with the wound
site. It is believed that having more wound contact may increase
the ability of the fluid transport layer to absorb excessive fluid
from the wound site and further promote wound healing. These window
and border adhesive layers are further illustrated one or more of
the Figures presented herein.
[0060] The percent of perforation (e.g. open space due to apertures
or holes or openings) present in the perforated silicone gel
adhesive layer may vary. In one aspect, the percent of perforation
is in the range from about 5 percent to about 95 percent, or in the
range from about 10 percent to about 40 percent, or even in the
range from about 11 percent to about 20 percent.
[0061] The perforated silicone gel adhesive layer may be of any
thickness. In one aspect, the perforated silicone gel adhesive
layer has a thickness in the range from about 0.05 mm to about 1.0
mm, or in the range from about 0.1 mm to about 0.5 mm, or even in
the range from about 0.2 mm to about 0.48 mm.
[0062] The adhesive characteristics of the silicone layer are
fine-tuned and balanced to allow a minimum amount of adhesion to
the skin and/or wound site for ease of application of the wound
care device, but is contained and capped at a maximum amount of
adhesion to prevent disruption of wound healing upon removal of the
device from the wound. Without being bound by theory, it is
believed that silicone is a preferably adhesive due to its high
initial tack which can adhere to the skin for several days.
However, the adhesive is gentle enough to not damage the wound or
periwound skin upon removal. The adhesive characteristics may be
measured by ASTM D6862-11, Standard Test Method for 90 Degree Peel
Resistance of Adhesives. Ideal adhesion of the wound care device on
a stainless steel substrate may be found in the range from about
0.1 N/25 mm to about 4.0 N/25 mm, or in the range from about 0.5
N/25 mm to about 2.0 N/25 mm.
[0063] Additional layers of material may be included with the wound
care device of the present invention. For example, a fluid
retentive layer may be attached to the fabric layer. The fluid
retentive layer may be attached using hot melt adhesive. Also, an
occlusive (non-perforated) film layer may be attached to the foam
layer. The occlusive film layer may be attached using hot melt
adhesive. Finally, a release liner may be included as part of the
packaging of the wound care device. It functions to protect the
silicone gel adhesive prior to use. The release liner is intended
to be removed prior to use of the wound care device. The release
liner may be comprised of material selected from the group
consisting of polycarbonate, polypropylene, polyethylene, coated
paper, and the like, and combinations thereof. The release liner
may be printed.
[0064] The fluid retentive layer may be selected from the group
consisting of foams, textile materials (e.g. woven, knit, and
nonwoven textile materials), alginates, superabsorbent polymers,
gels (e.g., hydrogels), and combinations or mixtures thereof. The
fluid retentive layer can also comprise a combination of two or
more discrete layers, which layers can comprise any of the
absorptive materials listed above. In a specific embodiment, the
fluid retentive layer can be a foam, such as an open cell,
non-reticulated polymer foam. Such foams can be made from any
suitable material including, but not limited to, polyurethane
polymers. In one aspect, a polyurethane polymer used in making such
a foam can be a polyester-based polyurethane polymer (i.e., a
polyurethane polymer made from a reaction mixture containing a
polyester polyol).
[0065] The fluid retentive layer of the wound care device may
exhibit any suitable absorptive capacity. For example, the fluid
retentive layer may exhibit a fluid absorption of about 100 wt % or
more based on the weight of the fluid retentive layer. In a
specific embodiment, the fluid retentive layer may exhibit a fluid
absorption of about 200 wt % or more, about 300 wt % or more, about
400 wt % or more, about 500 wt % or more, about 600 wt % or more,
about 700 wt % or more, about 800 wt % or more, about 900 wt % or
more, or about 1000 wt % or more based on the weight of the fluid
retentive layer. The absorptive capacity of the fluid retentive
layer may be measured by any suitable means. For example, the
absorptive capacity of the fluid retentive layer may be measured by
immersing a known weight of the fluid retentive layer in
phosphate-buffered saline containing 0.9 wt % sodium chloride at
37.degree. C. for 30 minutes.
[0066] Thus, the wound care device of the present invention is
comprised of a fabric layer and a perforated silicone gel adhesive
layer. The wound care device may optionally include a release liner
that is substantially coextensive with the silicone layer. The
wound care device may also optionally include a fluid retentive
layer that is attached to the fabric layer. The fluid retentive
layer may or may not be substantially coextensive with the fabric
layer. Another optional layer comprises an occlusive film layer. In
one aspect, the occlusive film layer is substantially coextensive
with the fluid retentive layer. The occlusive film layer may be
printed with a product logo or other product identification
information.
[0067] The wound care device of the present invention may be of any
thickness, depending on the construction of the fabric and the
thickness of the perforated silicone gel adhesive layer. In one
aspect, the thickness of the wound care device may be in the range
from about 25 to about 60 mils, or in the range from about 35 to
about 50 mils, or even in the range from about 38 to about 45 mils.
It should be understood, and is exemplified herein, that thickness
measurements may be increased when the wound care device also
includes an antimicrobial finish on one or more surfaces of the
wound care device.
[0068] An additional advantageous feature of the silver-containing
wound care device of the present invention is its ability to
substantially maintain its original color, despite the presence of
effective amounts of a silver-based antimicrobial agent. The
elimination of color normally associated with the inclusion of
silver-based antimicrobials is highly beneficial and desirable. The
wound care devices (preferably, white-colored), as will be
described herein, allow users thereof and their health care
providers to monitor the exudates from the wound. Further, the
present wound care devices exhibit long-term color stability (that
is, their color does not change significantly over time while in
production, transit, or storage). Finally, because the present
wound care device is not discolored by the addition of the
silver-based antimicrobial agent, a variety of substrate colors may
be utilized or the finished wound care devices may be dyed or
colored to any desired shade or hue with any type of colorant, such
as, for example, pigments, dyes, tints, and the like. Thus, one or
more layers of the wound care device may contain a coloring agent.
The coloring agent is selected from the group consisting of
pigments, dyes, tints, and the like, and combinations thereof.
Antimicrobial and Other Agents
[0069] The particular antimicrobial treatment which may be applied
to the wound care device of the present invention comprises at
least one silver ion-releasing compound selected from the group
consisting of silver ion exchange materials (e.g. silver zirconium
phosphates, silver calcium phosphates and silver zeolites), silver
particles (e.g. silver metal, nanosilver, colloidal silver), silver
salts (e.g. AgCl, Ag.sub.2CO.sub.3), silver glass, and mixtures
thereof. One preferred silver ion-containing compound is an
antimicrobial silver sodium hydrogen zirconium phosphate available
from Milliken & Company of Spartanburg, S.C., sold under the
tradename AlphaSan.RTM.. Other potentially preferred
silver-containing antimicrobials suitable for use herein--including
silver zeolites, such as a silver ion-loaded zeolite available from
Sinanen Co., Ltd. of Tokyo, Japan under the tradename Zeomic.RTM.,
and silver glass, such as those available from Ishizuka Glass Co.,
Ltd. of Japan under the tradename Ionpure.RTM.--may be utilized
either in addition to, or as a substitute for, the preferred
species listed above. Other silver ion-containing materials may
also be used. Various combinations of these silver-containing
materials may be made if adjustments to the silver release rate
over time are desired.
[0070] Generally, the silver-based compound is added in an amount
from about 0.01% to about 60% by total weight of the particular
finish composition; more preferably, from about 0.05% to about 40%;
and most preferably, from about 0.1% to about 30%. The
antimicrobial finish itself, including any desired binders, wetting
agents, odor absorbing agents, leveling agents, adherents,
thickeners, and the like, is added to the substrate in an amount of
at least about 0.01% of the total device weight.
[0071] A binder material has been found useful in preventing the
antimicrobial from flaking onto the wound. Preferably, this
component is a polyurethane-based binding agent, although a wide
variety of cationic, anionic, and non-ionic binders may also be
used, either alone or in combination. Preferably, the binding agent
is biocompatible such that is does not cause negative reactions in
the wound. In essence, such binders provide durability by adhering
the antimicrobial to the target substrate, such as fibers or
fabrics, without negatively affecting the release of silver ions to
the wound.
[0072] Total add-on levels of silver to the target substrate may be
20 ppm or higher. More preferably, total add-on levels of silver
may be 200 ppm or higher. Although an upper boundary limit of
silver add-on levels to the target substrate has not been
determined, consideration of the manufacturing economics and the
potential to irritate a sensitive wound site suggests avoiding
excessive silver levels.
Application of Antimicrobial and Other Agents to Substrate
[0073] Silver ion-containing compounds (such as AlphaSan.RTM.,
Zeomic.RTM., or Ionpure.RTM.) may be admixed in an aqueous
dispersion with a binder to form a bath into which the target
substrate is immersed. Other similar types of compounds that
provide silver ions may also be utilized.
[0074] When specific polyurethane-based binder materials are
utilized, the antimicrobial characteristics of the treated
substrate are effective with regard to the amount of surface
available silver that is released to kill bacteria, without
altering the color of the treated substrate (that is, while
substantially maintaining its original appearance). While it
currently appears that the use of polyurethane-based binder resins
are preferred due to their allowance of silver release and
bio-neutral properties, in practice essentially any effective
cationic, anionic, or non-ionic binder resin that is not toxic to
the wound may be used.
[0075] An acceptable method of providing a durable antimicrobial
silver-treated fabric surface is the application of a silver
ion-containing compound and polyurethane-based binder resin from a
bath mixture. This mixture of antimicrobial compound and binder
resin may be applied through any technique as is known in the art,
including spraying, dipping, padding, foaming, printing, and the
like. By using one or more of these application techniques, a
fabric may be treated with the antimicrobial compound and binder
resin on only one side of the fabric (e.g. the wound contact
surface of a wound care device), or it may be treated on both sides
of the fabric.
[0076] The wound care device may then be cut into any geometric
shape or size depending upon its end-use application. The wound
care device may be cut using a computer controlled cutting device
such as a Gerber machine. It may also be cut using a mechanical dye
cutter, hot knife, straight blade, or rotary blade. The wound care
device may be cut into any size, such as, for example, a square,
rectangle, triangle, circle and the like. The length of the wound
care device may be 1'', 2'', 3'', 4'', 5'', 6'', 7'', and the like
and longer. The width may be 1'', 2'', 3'', 4'', 5'', 6'', 7'', and
the like and longer. The wound care device may be comprised of any
combination of length and width. In one aspect, the wound care
device may be 2'' by 2'', 2'' by 3'', 3'' by 3'', 4'' by 2'', 4''
by 3'', 4'' by 4'', or 4'' by 5'' in size. The wound care device
may also be of any variety of whimsical shapes, such as, dog bone
shape, heart shape, smiley face, or any other shape that is
desired. The wound care device may also be sterilized prior to use
via a variety of heat, chemical and/or radiation techniques. In one
aspect, sterilization may be accomplished via gamma radiation.
[0077] Turning to the Figures, FIGS. 1A and 1B illustrate wound
care device 101 of the present invention. In consecutive order from
wound contact surface to the surface furthest away from the wound,
wound care device 101 comprises apertured (or perforated) adhesive
layer 102, fluid transport layer 106 having a wound contact (or
wound facing) surface 108 and fluid reservoir surface 110, adhesive
layer 114, fluid retentive layer 120, adhesive layer 128, and
occlusive film layer 130 having an inner surface 132 and an outer
surface 134. Apertured adhesive layer 102 contains multiple
apertures (e.g. holes or openings) 104.
[0078] The fluid transport layer 106 has a first surface 108, which
provides a fluid-contacting or skin-facing surface for the wound
care device 101, and a second surface 110. Adhesive layer 102 is
applied to the first surface 108 of the fluid transport layer 106.
The fluid retentive layer 120 has a first surface 122 and second
surface 124 and is positioned so that the first surface 122 is
adjacent to the fluid reservoir surface 110 of the fluid transport
layer 106. Thus, the fluid retentive layer 120 can act as a
reservoir for the fluids taken up by the fluid transport layer 106.
As depicted in FIGS. 1A and 1B, the fluid transport layer, fluid
retentive layer, and, if present, occlusive film layer may be
attached to each other using adhesive layers 114,128.
[0079] FIGS. 10 and 1D illustrate yet another embodiment of the
wound care device of the present invention. In FIGS. 10 and 1D,
wound care device 101 is similar to the device of FIGS. 1A and 1B
except that wound care device 101 has been inverted in order to
better illustrate the alternative embodiments of apertured adhesive
layer 102. Herein, FIG. 10 contains wound care device 101 having,
in consecutive order from wound contact surface to the surface
furthest away from the wound, apertured adhesive layer 102
containing apertures 104, fluid transport layer 106, adhesive layer
114, fluid retentive layer 120, adhesive layer 128, and occlusive
film layer 130. The fluid transport layer 106 has a first surface
108, which provides a fluid-contacting or skin-facing surface for
the wound care device 101, and a second surface 110. The fluid
retentive layer 120 has a first surface 122 and second surface 124,
and occlusive film layer 130 has an inner surface 132 and an outer
surface 134. FIG. 10 is provided to illustrate that, in one aspect
of the invention, apertures 104 may be of an alternative shape and
size than that which is illustrated in FIG. 1B. In this instance,
apertures 104 include four large squares situated in a uniform
arrangement across the surface of apertured adhesive layer 102.
Such an arrangement allows for greater contact between the wound
site and fluid transport layer 106. FIG. 1D is the same as FIG. 10,
except that apertured adhesive layer 102 is provided as a border
(or window) adhesive layer having one large opening in the
approximate center of layer 102. FIG. 1D thus illustrates an
exemplary configuration of layer 102 which allows for even greater
contact between the wound site and fluid transport layer 106.
[0080] FIG. 1E illustrates yet another embodiment of the wound care
device according to the present invention. FIG. 1E is the same as
shown and described for FIG. 1D, except that apertured adhesive
layer 102 is shown to be dimensionally larger at its outer edges
than all other layers of wound care device 101. This feature
creates an outer adhesive border around the remaining layers of the
wound care device. While shown to be larger on all four edges in
FIG. 1E, it is contemplated to be within the scope of the present
invention that apertured layer 102 may be dimensionally larger at
its outer edges on one outer edge, on two outer edges, on three
outer edges, or on all four outer edges.
[0081] As depicted in FIG. 2, fluid transport layer 200 is
comprised of hydrophilic fibers 202 and hydrophobic fibers 204
intermeshed together in a jersey knit construction.
[0082] FIG. 3A illustrates adhesive layer 102 which is an apertured
film having multiple discrete apertures (perforations or
discontinuities) 104. FIG. 3B illustrates yet another embodiment of
the invention wherein adhesive layer 102 is comprised of three
layers of material forming a trilaminate adhesive layer. The
trilaminate is formed of layers 102a, 102b and 102c. In one aspect
layer 102a is comprised of an acrylic material, layer 102b is
comprised of a polyurethane film, and 102c is comprised of silicone
adhesive.
[0083] As can be seen in FIG. 4, perforated adhesive layer 102
comprises a plurality of discrete apertures (perforations or
discontinuities) 104. These apertures preferably have a dimension
sufficient to permit the passage of fluid through adhesive layer
102 to the underlying fluid transport layer formed by the yarn(s)
202 and the effect yarn(s) 204.
[0084] FIGS. 5 to 9 are photomicrographs of Example 2, described in
greater detail later herein. FIG. 5 illustrates multiple apertures
present in the adhesive layer of the wound care device of the
present invention. Also, illustrated in FIG. 5 is the fiber of the
fluid transport layer present in the layer immediately behind/under
the adhesive layer. FIG. 5 also illustrates one embodiment of the
present invention wherein the apertures in the adhesive layer are
present in a substantially uniform pattern. FIG. 6 is a view
similar to FIG. 5, but at higher magnification and at a 50 degree
angle. FIG. 6 further illustrates the fibers protruding into the
apertures of the wound care device. FIG. 7 shows one apertures of
the wound care device of the present invention at 80.times.
magnification. Polymer stress lines are evident in FIG. 7 and are
believed to be caused from puncturing the adhesive layer to form
the apertures. FIG. 8 illustrates the silver-containing compound
present on the fibers of the fluid transport layer of the wound
care device. FIG. 9 is a magnified cross-sectional view of some of
the layers of the wound care device. FIG. 9 illustrates, from top
to bottom: the release liner followed by the silicone adhesive
layer followed by the fluid transport layer followed by the fluid
retentive layer (open-cell polyurethane foam). The lightest colored
area along the top surface and the bottom surface of the fluid
transport layer is the silver-containing compound. In this
embodiment, the silver-containing compound is present on both
surfaces of the fluid transport layer. Also illustrated in FIG. 9
is a single aperture.
[0085] FIGS. 10 and 11 are photomicrographs of Comparative Example
1, which is described in more detail further herein. FIG. 10
illustrates the multiple apertures present in the adhesive layer of
the wound dressing. However, there is no fiber-containing layer
contained within this dressing as is apparent by looking at the
photomicrographs. Rather, an open-cell foam is present behind/under
the adhesive layer. FIG. 10 also illustrates the apertures present
in Comparative Example 1 in a non-uniform arrangement/pattern. FIG.
11 is a greater magnified view of the adhesive layer of Comparative
Example 1.
[0086] FIGS. 12 and 13 are photomicrographs of Comparative Example
3, which is described in more detail further herein. FIG. 12
illustrates the multiple apertures present in the adhesive layer of
the wound dressing. However, there is no fiber-containing layer
contained within this dressing as is apparent by looking at the
photomicrographs. Rather, an open-cell foam is present behind/under
the adhesive layer. FIG. 13 is a magnified view of a single
aperture present in the adhesive layer of Comparative Example
3.
[0087] The following examples further illustrate the present wound
care device having fluid transfer properties, but are not to be
construed as limiting the invention as defined in the claims
appended hereto. All parts and percents given in these examples are
by weight unless otherwise indicated.
Sample Creation and Evaluation
A. Substrate Descriptions
[0088] The fabric used for Examples 1 and 2 was a jersey knit
(circular knit), multi-polymer fabric sold by Milliken &
Company. The fabric was single layer of fabric comprised of
approximately 66% continuous filament polyamide yarn, 19%
continuous filament polyester yarn, and 15% continuous filament
spandex yarn. The polyamide yarn was comprised of 2 plies of 40
denier/34 filament count nylon 6 fiber that was exposed to a
texturing process prior to knitting. The polyester yarn was
comprised of single ply 70 denier/34 filament count fiber that was
exposed to a texturing process prior to knitting. The spandex yarn
was comprised of 55 denier/3 filament count fiber.
[0089] The fabric was knitted in such as manner as to give a
distinct nylon side and a distinct polyester side. The polyester
side of the fabric was exposed to a face-finishing process known as
sanding.
[0090] The fabric was passed through a bath containing an
antimicrobial formulation (further described below) and
subsequently through squeeze rollers to achieve a wet pick-up of
about 85%. The fabric was then dried in a tenter frame to remove
excess liquid.
[0091] Silicone Gel Adhesive A was Acrysil.TM. 150, a trilaminate
film comprised of a layer of silicone adhesive, a polyurethane
membrane, and a layer of acrylic adhesive. Acrysil.TM. 150 is
commercially available from Zodiac Coating of Pusignan, France. The
film contained perforations having a size of less than 1.0 mm.
[0092] Silicone Gel Adhesive B was Acrysil.TM. 150, a trilaminate
film comprised of a layer of silicone adhesive, a polyurethane
membrane, and a layer of acrylic adhesive. Acrysil.TM. 150 is
commercially available from Zodiac Coating of Pusignan, France. The
film contained perforations having a size of about 1.8 mm.
[0093] Silicone Gel Adhesive C-1 was P-Derm.RTM. PS-2046, a
perforated trilaminate film comprised of high adhesion silicone gel
skin contact adhesive (1.3N/25 mm), polyurethane, and medical
pressure sensitive acrylic. This adhesive has a thickness of 0.22
mm and hole size of 1.5 mm with 17% open space. P-Derm.RTM. PS-2046
is commercially available from Polymer Science, Inc. of Monticello,
Ind.
[0094] Silicone Gel Adhesive C-2 was P-Derm.RTM. PS-2048, a
perforated trilaminate film comprised of high initial tack silicone
gel skin contact adhesive (1.1N/25 mm), polyurethane, and medical
pressure sensitive acrylic. This adhesive has a thickness of 0.22
mm and hole size of 1.5 mm with 17% open space. P-Derm.RTM. PS-2048
is commercially available from Polymer Science, Inc. of Monticello,
Ind.
[0095] Silicone Gel Adhesive D was Acrysil.TM. 150, a trilaminate
film comprised of a layer of silicone adhesive, a polyurethane
membrane, and a layer of acrylic adhesive. Acrysil.TM. 150 is
commercially available from Zodiac Coating of Pusignan, France.
Perforations were added to Silicone Gel Adhesive D having a size of
about 6.0 mm. [we added the perforations, correct?]
[0096] Silicone Gel Adhesive E was Acrysil.TM. 150 with no
perforations.
B. Antimicrobial Coating Formulations
[0097] Various dispersions of an antimicrobial finish include
combinations of the following components: [0098] Antimicrobial
AlphaSan.RTM. RC2000 silver-based ion exchange compound, available
from Milliken & Company of Spartanburg, S.C.; [0099]
Witcobond.RTM. W-293 (67% solids) or Witcobond UCX-281F (40%
solids), polyurethane binders available from Chemtura Corporation
of Middlebury, Conn.; and [0100] Water.
Example 1
[0101] Example 1 was comprised of the following sequential layers:
Silicone Gel Adhesive A, a jersey knit fabric (described
previously, available from Milliken & Company of Spartanburg,
S.C.), a hot melt adhesive (copolyamide, PA1008/1-060-014.25
available from SpunFab), a polyurethane foam (Medisponge.RTM. 60P
available from Essentra), a hot melt adhesive (copolyamide,
PA1008/1-060-014.25 available from SpunFab), and a polyurethane
film (Inspire.RTM. 2340 available from Coveris). The Inspire.RTM.
film was printed with logo and product identification. No silver
antimicrobial was included.
[0102] A layer of hot melt adhesive was laid over the top of the
jersey knit fabric. The fabric-hot melt composite was then fed into
a laminating machine, along with all the additional layers in the
correct order/configuration as outlined above. The machine was set
at a temperature of 185.degree. C. and a speed of 2.6 m/min. The
laminate product was wound on a take-up roller.
Example 2
[0103] Example 2 was the same as Example 1, except Silicone Gel
Adhesive A was replaced with Silicone Gel Adhesive B.
Modified Example 2
[0104] Modified Example 2 was the same as Example 2, except
individual fibers from the fluid transport layer were pulled
through about 10% of the apertures in the silicone adhesive layer
using tweezers.
Example 3
[0105] Example 3 was the same as Example 1, except Silicone Gel
Adhesive A was replaced with Silicone Gel Adhesive C-1.
Example 4
[0106] Example 4 was the same as Example 1, except Silicone Gel
Adhesive A was replaced with Silicone Gel Adhesive D.
Example 5
[0107] Example 5 was the Ultra.RTM. foam dressing (available from
Milliken & Company of Spartanburg, S.C.), which was comprised
of a layer of Silicone Adhesive B (described previously), a layer
of jersey knit fabric (described previously), and a layer of
polyurethane foam.
C. Comparative Sample Descriptions
[0108] Several commercially available wound care devices were also
purchased for evaluation. They include the following: [0109]
COMPARATIVE EXAMPLE 1--"Mepilex.RTM. Ag", a non-adhesive single
layer polyurethane foam dressing that contains silver; available
from Molnlycke Health Care AB of Gothenburg, Sweden. [0110]
COMPARATIVE EXAMPLE 2--"Mepilex.RTM.", a non-adhesive single layer
polyurethane foam dressing; available from Molnlycke Health Care AB
of Gothenburg, Sweden. [0111] COMPARATIVE EXAMPLE 3--"Allevyn.RTM.
Gentle", a three-layer adhesive dressing comprised of a top film
layer, a polyurethane foam core middle layer, and an adhesive wound
contact layer; available from Smith & Nephew of London, United
Kingdom. [0112] COMPARATIVE EXAMPLE 4--"Allevyn.RTM. Ag", a
three-layer adhesive dressing comprised of a top film layer, a
silver-containing (silver sulfadiazine) polyurethane foam core
middle layer, and an adhesive wound contact layer; available from
Smith & Nephew of London, United Kingdom. [0113] COMPARATIVE
EXAMPLE 5--"Optifoam.RTM. Ag+", a non-adhesive dressing comprised
of a silver-containing (ionic silver) polyurethane foam layer and a
film layer; available from Medline Industries, Inc. of Mundelein,
Ill. [0114] COMPARATIVE EXAMPLE 6--"Optifoam.RTM. Gentle", a
silicone adhesive dressing comprised of a silicone adhesive layer,
a polyurethane foam layer, and a film layer; available from Medline
Industries, Inc. of Mundelein, Ill. [0115] COMPARATIVE EXAMPLE
7--"Cutimed.RTM. Siltec", a silicone adhesive dressing comprised of
a perforated silicone adhesive layer, a polyurethane foam layer
that contains superabsorbent particles, and a polyurethane film
layer; available from BSN Medical of Hamburg, Germany.
D. Example Testing and Evaluation
[0116] Each of the above examples was tested for a variety of
characteristics as will be described below. The silicone adhesive
of the inventive wound care device was the intended wound contact
surface. Further, commercially available products (referred to as
Comparative Examples 1-7 and described above) were also tested for
comparison with the inventive wound care device. The test
procedures will be described in greater detail in the following
description. However, a listing of the tests employed is found
below.
TABLE-US-00002 Test 1. Drop Disappearance Test (internally
developed method) Test 2. Periwound Protection Test (internally
developed method) Test 3. Vertical Leg Model (internally developed
method) Test 4. Vertical Wicking Test 5. Peel Strength (ASTM
D6862-11) Test 6. Free Swell Bulk Absorption Test (EN 13726-1:
2002, Part 1, Test 3.2: Free Swell Absorption Capacity)
Test 1: Drop Disappearance Test
[0117] The purpose of this test is to measure the amount of time it
takes for a single drop of fluid to be absorbed into the substrate.
The fluid used was simulated wound fluid. Simulated wound fluid is
a solution of deionized water containing 142 mM of sodium chloride
and 2.5 mM of calcium chloride. The simulated wound fluid is
isotonic to human blood. The simulated wound fluid was contained
within a 2 mL syringe. Two millimeters of fluid were dispensed by
hand onto the approximate center of the substrate. The time it took
for the drop to disappear (to be absorbed into the substrate) was
recorded. The test was stopped after 600 seconds was reached. Test
results are provided in Table 1.
TABLE-US-00003 TABLE 1 Drop Disappearance Properties of Inventive
and Comparative Wound Care Devices Sample Time (seconds) Example 1
600 Example 2 8 Example 3 15 Example 4 34 Example 5 5 Comparative
Example 1 600 Comparative Example 2 600 Comparative Example 3 13
Comparative Example 4 n/a Comparative Example 5 n/a Comparative
Example 6 120
[0118] The results shown in Table 1 demonstrate that the inventive
wound care device having a perforated adhesive film layer (wound
contact surface) with apertures of at least 1.8 mm in size
demonstrate the fastest drop disappearance.
Test 2: Periwound Protection Test
[0119] The purpose of this test is to measure the amount of
moisture or liquid that is transferred from the dressing to the
healthy periwound skin. Simulated wound fluid was used. The
apparatus was a syringe pump with 1/32'' internal diameter tubing
attached to a small hole in the center of a petri dish. This
simulated the wound. A pre-weighed, 2'' diameter piece of two-layer
gauze with a 10 mm hole in the center was placed on the petri dish
with the tubing hole centered within the hole in the gauze. The
gauze simulated the periwound skin. A 2'' diameter dressing cutout
was placed on top of the gauze and a weight of approximately 42
grams was placed on top of the dressing. Simulated wound fluid was
delivered to the "wound" at a rate of 0.2 mL/hr for 24 hours. At
the completion of the test, the weight of the gauze was recorded
and the percent fluid pick up was determined. Test results are
provided in Table 2.
TABLE-US-00004 TABLE 2 Periwound Protection of Inventive and
Comparative Wound Care Devices Sample Percent Pick Up (%) Example 1
842 +/- 402 Example 2 68 +/- 42 Example 3 13 +/- 3 Example 4 40 +/-
51 Example 5 51 +/- 21 Comparative Example 1 848 +/- 727
Comparative Example 2 963 +/- 584 Comparative Example 3 729 +/- 97
Comparative Example 6 167 +/- 258
[0120] The results shown in Table 2 demonstrate that the inventive
wound care device having a perforated adhesive film layer (wound
contact surface) with apertures of at least 1.5 mm in size
demonstrated a lower percent pick up and therefore greater
periwound protection.
Test 3: Vertical Leg Model Test
[0121] The purpose of this test is to measure the amount of fluid
that is absorbed by the wound care device over a period of time in
a vertical orientation prior to failure. The fluid used was
simulated wound fluid. Failure is defined as the point in time when
the wound care device either (a) started to peel from the nylon
surface of the leg model or completely fell off the leg model, or
(b) started to leak simulated wound fluid from the edges and/or
borders of the wound care device. Samples were run at 24 mL/hour
until failure. Test results are provided in Table 3.
TABLE-US-00005 TABLE 3 Vertical Leg Test Properties of Inventive
and Comparative Wound Care Devices Sample Fluid Absorbed (mL)
Example 1 47 Example 2 46 Example 3 44 Example 4 n/a Comparative
Example 1 18 Comparative Example 2 n/a Comparative Example 3 19
Comparative Example 4 n/a Comparative Example 5 n/a Comparative
Example 6 43 Comparative Example 7 14
[0122] The results shown in Table 3 demonstrate that the inventive
wound care device having a perforated adhesive film layer (wound
contact surface) with apertures of at least 1.5 mm in size
demonstrated a significant amount of fluid absorption in a vertical
orientation prior to failure.
Test 4: Vertical Wicking Test
[0123] The purpose of this test is to measure the amount of fluid
that is absorbed by the wound care device over a certain period of
time in a vertical orientation. The fluid used was simulated wound
fluid. Each sample was tested in triplicate. The average and
standard deviation was calculated and is presented in Table 4.
TABLE-US-00006 TABLE 4 Vertical Wicking Properties of Inventive and
Comparative Wound Care Devices Fluid Absorbed (mL) At 10 At 20 At
30 At 40 At 50 At 60 Sample seconds seconds seconds seconds seconds
seconds Example 1 n/a n/a n/a n/a n/a n/a Example 2 2.30 +/- 0.00
2.60 +/- 0.10 3.12 +/- 0.16 3.43 +/- 0.24 3.82 +/- 0.15 4.00 +/-
0.00 Example 3 2.27 +/- 0.15 3.02 +/- 0.14 3.53 +/- 0.21 3.87 +/-
0.23 4.00 +/- 0.00 4.00 +/- 0.00 Example 4 n/a n/a n/a n/a n/a n/a
Example 5 2.43 +/- 0.15 3.27 +/- 0.08 3.83 +/- 0.06 4.00 +/- 0.00
4.00 +/- 0.00 4.00 +/- 0.00 Comparative 1.40 +/- 0.10 1.47 +/- 0.06
1.47 +/- 0.06 1.50 +/- 0.00 1.50 +/- 0.00 1.53 +/- 0.06 Example 1
Comparative 0.97 +/- 0.21 1.08 +/- 0.18 1.25 +/- 0.05 1.37 +/- 0.08
1.50 +/- 0.13 1.60 +/- 0.05 Example 2 Comparative 1.17 +/- 0.06
1.25 +/- 0.05 1.37 +/- 0.06 1.43 +/- 0.03 1.57 +/- 0.08 1.68 +/-
0.08 Example 3 Comparative n/a n/a n/a n/a n/a n/a Example 4
Comparative n/a n/a n/a n/a n/a n/a Example 5 Comparative 1.68 +/-
0.03 1.93 +/- 0.06 2.63 +/- 0.03 2.90 +/- 0.00 3.13 +/- 0.03 3.33
+/- 0.03 Example 6 Comparative n/a n/a n/a n/a n/a n/a Example
7
[0124] The results shown in Table 4 demonstrate that the inventive
wound care device having a perforated adhesive film layer (wound
contact surface) with apertures of at least 1.5 mm in size
demonstrates a significant wicking ability in the vertical
direction.
Test 5: Peel Strength Test
[0125] The purpose of this test is to measure the amount of force
it takes to remove the wound care device from the surface of
stainless steel. Each sample was applied to the surface according
to the product directions. Removal of the sample was done by a
testing machine with a load weighing system. The force required to
remove each sample was recorded in grams of force (gf).
[0126] Test results are provided in Table 5.
TABLE-US-00007 TABLE 5 Peel Strength of Inventive and Comparative
Wound Care Devices Sample Peel Strength (gf) Example 5 193.640
Comparative Example 1 87.662 Comparative Example 2 87.361
Comparative Example 3 106.931 Comparative Example 6 274.968
[0127] The results shown in Table 5 demonstrate that the amount of
force needed to remove the inventive wound care device from the
stainless steel surface is found in between the amount of force
needed for removal of the Comparative Examples.
Test 6: Free Swell Bulk Absorption Test
[0128] The purpose of this test is to measure the absorptive
capacity of a dressing. The weight of a 5 cm by 5 cm sample of
dressing was recorded. The sample of dressing was added to a dish
with a quantity of 37.degree. C. simulated wound fluid that was
approximately 40 times the weight of the dressing. The dressing was
allowed to sit in the fluid for 30 min at 37.degree. C. At the end
of the test the sample was suspended for 30 seconds and weighed.
The absorptive capacity of the sample was determined. Each sample
was tested in triplicate. The average and standard deviation was
calculated and is presented in Table 6.
TABLE-US-00008 TABLE 6 Free Swell Bulk Absorption Properties of
Inventive and Comparative Wound Care Devices Sample Absorptive
Capacity (g/cm.sup.2) Example 1 6341 +/- 47 Example 2 5791 +/- 232
Example 3 6140 +/- 328 Example 4 5013 +/- 423 Example 5 5176 +/- 90
Comparative Example 1 7025 +/- 465 Comparative Example 2 7837 +/-
463 Comparative Example 3 4690 +/- 267 Comparative Example 6 5269
+/- 60 Comparative Example 7 9174 +/- 176
[0129] The results shown in Table 6 demonstrate that the inventive
wound care device having a perforated adhesive film layer (wound
contact surface) exhibits comparable absorptive capacity to the
Comparative Examples.
Test 7: Antimicrobial Efficacy
[0130] Antimicrobial efficacy against both Gram-positive (e.g.
Staphylococcus aureus ATCC #6538) and Gram-negative (e.g.
Klebsiella pneumoniae ATCC #4352) bacteria was measured for
inventive and comparative wound care devices. The quantitative
reduction of bacteria after exposure to the samples versus the
control was assessed using a modified version of AATCC Method
100.
[0131] Portions of each wound dressing sample (non-sterile 15 mm
diameter disks) were placed into 24-well microplates. With all
samples, the dressings were placed with the side down that normally
contacts the wound. Overnight cultures of the test microbes were
suspended in 5% nutrient broth in saline ca. 10E6 cells/ml. At time
0, each sample was pre-soaked in sterile saline via immersion. The
wells of the 24 well plate were inoculated with bacteria (0.1 ml of
ca. 10E6 cells/nil) and then the sample was placed contact side
down in the inoculum. The 24 well plates were then incubated at
37.degree. C. After incubation for 24 hours, the samples were
removed and placed into 50 ml centrifuge tubes filled with 5 ml of
a "wash solution" (Tryptic Soy Broth+0.7% Tween 80+0.1% cysteine
(to inactivate residual silver)). After vortexing to remove
attached cells, the number of viable cells in the solution was
quantified using a microtiter plate-based "Most-Probable Number"
assay. The recipe for full-strength Nutrient Broth indicated in
this method is 5 g/l peptone and 3 g/l beef extract. Duplicate
samples were tested against Staphylococcus aureus ATCC #6538 and
Klebsiella pneumoniae ATCC #4352.
[0132] The Control sample was Ultra.RTM. foam dressing (available
from Milliken & Company of Spartanburg, S.C.) which does not
contain a silicone adhesive layer. The results are shown in Table 7
and FIG. 14.
TABLE-US-00009 TABLE 7 Antimicrobial Efficacy Against Gram-Positive
and Gram-Negative Bacteria vs. Control Average Log Average Log
Reduction vs. Control Reduction vs. Control Against Against Sample
ID Klebsiella pneumoniae Staphylococcus aureus Example 1 3.66 +/-
0.18 2.36 +/- 0.90 (<1.0 mm apertures) Example 2 4.31 +/- 0.59
2.83 +/- 0.67 (1.8 mm apertures) Modified Example 2 3.49 +/- 0.35
2.68 +/- 0.04 (1.8 mm apertures, fiber pull-through) Example 3 3.98
+/- 0.27 2.61 +/- 0.07 (1.5 mm apertures) Comparative Example 1
4.31 +/- 0.59 2.98 +/- 0.45 Control 6.02 +/- 0.18 4.00 +/- 0.24
(silver, but no silicone)
[0133] The results in Table 7 and FIG. 14 indicate that the
inventive wound care devices exhibit antimicrobial efficacy against
both Gram-positive and Gram-negative bacteria. The antimicrobial
efficacy is comparable to other commercially available
silver-containing wound care devices (Comparative Example 1).
Examples 1 to 3 exhibited at least 50% of the antimicrobial
efficacy shown by the control sample (no silicone adhesive layer).
In this instance, the data may be interpreted to illustrate that
the antimicrobial efficacy is reduced by less than 50% when a
silicone adhesive layer is included in the wound care device. Some
of Examples 1 to 3 exhibited at least 70% of the antimicrobial
efficacy shown by the control sample (no silicone adhesive layer).
In this instance, the data may be interpreted to illustrate that
the antimicrobial efficacy is reduced by less than 30% when a
silicone adhesive layer is included in the wound care device.
[0134] For this testing, Klebsiella pneumoniae was selected as the
representative Gram-negative microbe and Staphylococcus aureus was
selected as the representative Gram-positive microbe. However, it
should be understood to be within the scope of this invention that
the wound care device of the present invention would exhibit
similar antimicrobial efficacy against other Gram-positive and
Gram-negative bacteria, as well as against fungi such as C.
albicans.
[0135] Additional test methods useful for analyzing the wound care
device of the present invention are as follows:
TABLE-US-00010 Test 8. Fluid Transport Test (Internally developed
method) Test 9. Tensile Strength Test (ASTM D 5034) Test 10. Zone
of Inhibition Test (Kirby-Bauer Agar Diffusion Assay) Test 11.
Total AlphaSan .RTM. RC 2000 Content Test (Ashing Technique) Test
12. Conductivity/Resistivity Test (AATCC Test Method 76) Test 13.
Thickness Test (ASTM D 1777-96)
[0136] Many of these tests were conducted in commonly owned U.S.
Pat. Nos. 7,842,306; 8,021,685, and 8,394,403, all of which are
incorporated by reference herein.
Test 8: Fluid Transport Test
[0137] The purpose of this test is to measure the amount of fluid
that is transported from the wound contact side of the wound care
device (Side A) to the non-wound contact side of the device (Side
B). The test also attempts to measure the amount of fluid pushed
back to the wound contact side of the device (Side A).
[0138] Simulated wound fluid ("SWF") was prepared by adding 16.60 g
NaCl and 0.56 g CaCl.sub.2) to a 2 L volumetric flask. The flask
was then filled to volume (2000 mL total) with deionized water. The
flask was then capped and shaken until all of the salts were
completely dissolved. The simulated wound fluid is comprised of
0.142M (142 mM) NaCl (aq) and 0.0025M (2.5 mM) CaCl.sub.2)
(aq).
[0139] A test sample of a wound care device (5 cm in diameter) was
placed onto a polypropylene disc (5 cm in diameter). Twenty drops
of simulated wound fluid was added to Side A of the test sample
using a dropper. The test sample was allowed to rest in a
horizontal position for 2 minutes. The test sample was then
sandwiched in a vertical position between two discs of filter paper
(Whitman filter paper 3, diameter=110 mm) using a clamp--Filter
Paper A contacted Side A of the test sample and Filter Paper B
contacted Side B of the test sample. The test sample was held in
this position for 5 seconds. It was determined that the clamp
exerts a pressure of 340 mm Hg.
[0140] Filter papers A and B had been weighed prior to the test.
They were then weighed after the test and difference in weight was
determined. This weight difference provides a calculation of the
amount of SWF transferred from the wound care device to Filter
Paper A and/or B.
[0141] The SWF was added to the polyester side ("Side A") of the
wound care device of the present invention. SWF was added to the
wound contact side of competitive dressings, as directed by the
product brochures.
[0142] The values are provided as "percent weight change." The
percent weight change represents the weight of the fluid absorbed
relative to the dry weight of the filter paper. It is calculated by
subtracting the weight of the dry filter paper (grams) from the
weight of the wet filter paper (grams) and dividing this difference
by the weight of the dry filter paper. This value is then
multiplied by 100.
Test 9: Tensile Strength
[0143] Tensile strength (grab) of various wound care devices was
determined using ASTM D 5034. The purpose of this test is to
determine structural integrity of wet and dry wound care devices.
The devices were wetted by dipping them in simulated wound fluid
(same formulation as described previously). Measurements are shown
in pounds of force (lbf). Higher values indicate that more force
was needed to tear the sample.
Test 10: Zone of Inhibition Test
[0144] Zone of Inhibition testing may be conducted to determine the
antimicrobial activity of various wound care devices against
several microbes using a modified version of the Kirby-Bauer
Susceptibility Test. A brief description of the test method is
included below. A full description of the test method may be found
in the following document: National Committee for Clinical
Laboratory Studies (NCCLS) M2-A8: Performance Standards for
Antimicrobial Disk Susceptibility Tests; Approved Standard--Eighth
Edition; 2003.
[0145] Several Gram-positive and Gram-negative bacteria as well as
fungi (yeast) may be chosen to illustrate the antimicrobial
efficacy of the inventive wound care device. Gram-positive bacteria
include, for example and without limitation, Staphylococcus aureus,
Clostridium perfringens, Enterococcus faecium and Bacillus cereus.
Gram-negative bacteria include, for example and without limitation,
Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii,
Enterobacter cloacae, Proteus mirabilis, and Pseudomonas
aeruginosa. Fungi, such as yeast, include for example, Candida
albicans and Saccharomyces cerevisiae.
[0146] An overnight culture of the test microbe was diluted into
saline (0.85% NaCl) to a concentration of 10.sup.6 cells/ml. Petri
dishes containing Diagnostic Sensitivity Test (DST) Agar were
inoculated with 0.25 ml of the cell suspension and incubated for 1
hour. A sample (15 mm diameter circle) of each wound care device
was then placed at the center of the agar plate. The agar plate was
incubated for 24 hours at 37.degree. C. After measuring the extent
of the zones (in mm), the samples were transferred to a fresh DST
plate inoculated with the same microbe. The process was repeated
for three days (total).
Test 11: Total AlphaSan.RTM. Content
[0147] Total ALPHASAN.RTM. Content Test
[0148] The amount of AlphaSan.RTM. antimicrobial incorporated into
or onto an article can be determined by measurement of elements
unique to the antimicrobial compound. For AlphaSan.RTM.
antimicrobial, the two elements of highest abundance are silver or
zirconium. Because zirconium is more abundant in the AlphaSan.RTM.
antimicrobial product and is easier to measure, it is preferable to
use zirconium as the signature element for determining the level of
AlphaSan.RTM. antimicrobial in an article. The amount of
AlphaSan.RTM. antimicrobial incorporated into or onto the wound
care device was determined using the following ashing
technique.
[0149] A sample of fabric (weighing approximately 1 gram but with
weight measured to four significant digits) was placed in a clean,
dry ceramic crucible which had been weighed. The crucible
containing the fabric sample was placed in a muffle furnace whose
temperature ramped up at 3.degree. C./minute to 750.degree. C. The
temperature was then held at 750.degree. C. for four hours. The
system was then cooled and the crucible transferred to a desiccator
in which it was allowed to reach an equilibrium temperature. The
crucible was then weighed. This provides the percent solids of
inorganic constituents.
[0150] The fabric sample was then ground in the ceramic crucible to
obtain a uniform sample. Approximately 0.05 g weight (again
measured to four significant digits) was then taken from the
ceramic crucible and placed in a platinum crucible. Four
milliliters of 50% HNO.sub.3, followed by 15-20 drops of 48% HF,
were added to the crucible. The crucible was heated over a hot
plate until the sample completely dissolved. The sample solution
was then transferred to a 100 mL volumetric flask.
[0151] The crucible was then rinsed with 5% HNO.sub.3, with the
rinse solution being added to the flask. The solution was diluted
to the 100 mL mark with 5% HNO.sub.3. The dilute solution was
transferred to a polyethylene storage container. Analysis for the
desired active ingredient (in this case, zirconium) was performed
using an Inductively Coupled Plasma Optical Emission Spectrometer
device (e.g., a Perkin Elmer Optima 4300DV). Calculations are
apparent to one skilled in the art. The amount of AlphaSan.RTM.
RC2000 present on the wound care device is provided as a weight
percent based on the weight of the fabric.
Test 12: Conductivity/Resistivity Test
[0152] The purpose of this test is to determine the conductivity
and resistivity (R) of the inventive wound care device. The test
was performed according to AATCC Test Method 76.
Test 13: Thickness Test
[0153] The purpose of this test was to measure the thickness of the
inventive wound care device. The test was performed according to
ASTM D 1777-96.
[0154] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0155] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the subject matter of this
application (especially in the context of the following claims) are
to be construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by context. The
terms "comprising," "having," "including," and "containing" are to
be construed as open-ended terms (i.e., meaning "including, but not
limited to,") unless otherwise noted. Recitation of ranges of
values herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range, unless otherwise indicated herein, and each separate value
is incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the subject matter of the
application and does not pose a limitation on the scope of the
subject matter unless otherwise claimed. No language in the
specification should be construed as indicating any non-claimed
element as essential to the practice of the subject matter
described herein.
[0156] Preferred embodiments of the subject matter of this
application are described herein, including the best mode known to
the inventors for carrying out the claimed subject matter.
Variations of those preferred embodiments may become apparent to
those of ordinary skill in the art upon reading the foregoing
description. The inventors expect skilled artisans to employ such
variations as appropriate, and the inventors intend for the subject
matter described herein to be practiced otherwise than as
specifically described herein. Accordingly, this disclosure
includes all modifications and equivalents of the subject matter
recited in the claims appended hereto as permitted by applicable
law. Moreover, any combination of the above-described elements in
all possible variations thereof is encompassed by the present
disclosure unless otherwise indicated herein or otherwise clearly
contradicted by context.
* * * * *