U.S. patent application number 15/181836 was filed with the patent office on 2016-12-08 for antimicrobial elastomeric articles.
This patent application is currently assigned to ALLEGIANCE CORPORATION. The applicant listed for this patent is ALLEGIANCE CORPORATION. Invention is credited to WALTER HAROLD ISAAC, NICHOLAS RYAN KROGMAN, KATIA SIMEONOV PETROV, SHIPING WANG.
Application Number | 20160354171 15/181836 |
Document ID | / |
Family ID | 48945741 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160354171 |
Kind Code |
A1 |
KROGMAN; NICHOLAS RYAN ; et
al. |
December 8, 2016 |
ANTIMICROBIAL ELASTOMERIC ARTICLES
Abstract
The present invention relates generally to methods of preparing
antimicrobial elastomeric articles that include an elastomeric
article having an antimicrobial coating provided thereon. The
antimicrobial elastomeric articles exhibit enhanced ability to
reduce or eliminate microbes that come in contact with the article.
Certain aspects of the invention are further directed to methods of
packaging the antimicrobial elastomeric articles, where the
packaged antimicrobial articles exhibit antimicrobial effectiveness
for an extended period of time as compared to unpackaged
antimicrobial articles. Antimicrobial elastomeric articles and
packaged antimicrobial elastomeric articles prepared in accordance
with the methods of the present invention are also provided.
Inventors: |
KROGMAN; NICHOLAS RYAN;
(GERMANTOWN, WI) ; ISAAC; WALTER HAROLD;
(LINDENHURST, IL) ; PETROV; KATIA SIMEONOV;
(VERNON HILLS, IL) ; WANG; SHIPING; (LIBERTYVILLE,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALLEGIANCE CORPORATION |
WAUKEGAN |
IL |
US |
|
|
Assignee: |
ALLEGIANCE CORPORATION
WAUKEGAN
IL
|
Family ID: |
48945741 |
Appl. No.: |
15/181836 |
Filed: |
June 14, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13396260 |
Feb 14, 2012 |
9386772 |
|
|
15181836 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 42/00 20160201;
A01N 25/10 20130101; C09D 5/14 20130101; A61L 2420/06 20130101;
A61L 2420/02 20130101; A61L 29/16 20130101; A61L 29/085 20130101;
C09D 133/08 20130101; B05D 1/18 20130101; A61L 2300/206 20130101;
C08J 2309/02 20130101; A61L 2300/404 20130101; A61B 42/40 20160201;
A61B 2017/00889 20130101; A61L 31/10 20130101; A61B 42/10 20160201;
A01N 25/34 20130101; A61L 31/049 20130101; C08J 7/0427 20200101;
C08J 2433/08 20130101; C09D 7/63 20180101; A61L 31/16 20130101;
A01N 47/44 20130101; B05D 1/02 20130101; A01N 47/44 20130101; A01N
25/10 20130101; A01N 25/34 20130101; A01N 2300/00 20130101; A01N
47/44 20130101; A01N 25/10 20130101; A01N 25/30 20130101; A01N
25/34 20130101; A01N 33/12 20130101; A01N 2300/00 20130101 |
International
Class: |
A61B 42/10 20060101
A61B042/10; A01N 25/10 20060101 A01N025/10; A61B 42/40 20060101
A61B042/40; A01N 47/44 20060101 A01N047/44; A61L 31/16 20060101
A61L031/16; A61L 31/10 20060101 A61L031/10 |
Claims
1. A method for preparing an antimicrobial elastomeric article,
comprising: exposing an elastomeric article to an environment
comprising about 10.3 g/m.sup.3 or less absolute humidity; coating
the elastomeric article with an antimicrobial coating composition
to form an antimicrobial elastomeric article; and exposing the
antimicrobial elastomeric article to an environment comprising
about 10.3 g/m.sup.3 or less absolute humidity, wherein the
antimicrobial elastomeric article reduces the initial number of
microorganisms present on a surface by at least 4 log.sub.10 within
5 minutes of being contacted by the antimicrobial elastomeric
article.
2. The method of claim 1, wherein the elastomeric article is
exposed to the environment for a period of from about 12 to about
48 hours.
3. The method of claim 1, wherein the antimicrobial elastomeric
article is exposed to the environment for a period of from about 12
to about 48 hours.
4. The method of claim 1, wherein the environment comprising about
10.3 g/m.sup.3 or less absolute humidity is maintained by a
structure selected from the group consisting of rooms, bags,
packages, boxes, and totes.
5. The method of claim 4, wherein the structure further comprises a
desiccant selected from the group consisting of silica gel,
aerogel, bentonite clay, activated alumina, nitrogen gas, and argon
gas.
6. The method of claim 1, wherein the antimicrobial coating
composition comprises an antimicrobial agent, a hydrophilic
polymer, and a hydrophobic oligomer.
7. The method of claim 4, wherein antimicrobial agent is selected
from the group consisting of biguanides (e.g., chlorhexidine
digluconate (CHG), chlorhexidine diacetate, chlorhexidine
dihydrochloride, chlorhexidine diphosphanilate, poly(hexamethylene
biguanide) (PHMB)), rifampin, minocycline, silver compounds (silver
chloride, silver oxide, silver sulfadiazine), triclosan, quaternary
ammonium compounds (e.g., benzalkonium chloride, tridodecyl methyl
ammonium chloride, didecyl dimethyl ammonium chloride, chloroallyl
hexaminium chloride, benzethonium chloride, methylbenzethonium
chloride, cetyl trimethyl ammonium bromide, cetyl pyridinium
chloride, dioctyldimethyl ammonium chloride), iron-sequestering
glycoproteins (e.g., lactoferrin, ovotransferrin/conalbumin),
cationic polypeptides (e.g., protamine, polylysine, lysozyme),
surfactants (e.g., SDS, Tween-80, surfactin, Nonoxynol-9), zinc
pyrithione, broad-spectrum antibiotics (quinolones,
fluoroquinolones, aminoglycosides and sulfonamides), antiseptic
agents (iodine, methenamine, nitrofurantoin, validixic acid), and
combinations thereof.
8. The method of claim 5, wherein antimicrobial agent comprises
chlorhexidine gluconate.
9. The method of claim 4, wherein the hydrophilic film-forming
polymer comprises cationic acrylic copolymer of acrylic acid and
methacrylic ester with quaternary ammonium groups.
10. The method of claim 4, wherein the hydrophobic oligomer
comprises wherein a nonionic paraffin wax of 25-30 carbons in chain
length
11. The method of claim 1, wherein the antimicrobial coating
composition is applied by a technique selected from the group
consisting of dipping, spraying, and tumbling.
12. The method of claim 11, wherein the antimicrobial coating
composition is applied while the elastomeric article is heated to
about 55.degree. C.
13. The method of claim 1, further comprising the step of drying
the elastomeric article at 55.degree. C..+-.5.degree. C. for about
30 minutes after coating the elastomeric article with the
antimicrobial coating composition.
14. The method of claim 1, wherein the antimicrobial elastomeric
article reduces the number of one or more microbes selected from
the group consisting of coagulase-negative Staphylococci,
Enterococci, fungi, Candida albicans, Staphylococcus aureus,
Enterobacter species, Enterococcus faecalis, Staphylococcus
epidermidis, Streptococcus viridans, Escherichia coli, Klebsiella
pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa,
Acinetobacter baumannii, Burkholderia cepacia, Varicella,
Clostridium difficile, Clostridium sordellii, Hepatitis A,
Hepatitis B, Hepatitis C, HIV/AIDS, methicillin-resistant
Staphylococcus aureus (MRSA), mumps, norovirus, parvovirus,
poliovirus, rubella, SARS, S. pneumoniae (including drug resistant
forms), vancomycin-intermediate Staphylococcus aureus (VISA),
vancomycin-resistant Staphylococcus aureus (VRSA), and
vancomycin-resistant Enterococci (VRE).
15. The method of claim 1, wherein the antimicrobial elastomeric
article is provided in a packaging system.
16. The method of claim 15, wherein the packaging system comprises
a packaging material selected from the group consisting of aluminum
foil, polyethylene film, nylon film, and laminates thereof.
17. The method of claim 15, wherein the packaging system comprises
desiccant material selected from the group consisting of silica
gel, aerogel, bentonite clay, activated alumina, nitrogen gas, and
argon gas.
18. The method of claim 15, wherein the relative humidity inside
the packaging system is below about 50% relative humidity.
19. The method of claim 15, wherein the packaged antimicrobial
elastomeric article is able to reduce the number of microorganisms
present on a surface by at least 4 log.sub.10 within 5 minutes of
being contacted by the antimicrobial elastomeric article for from
about 8 to about 26 weeks following packaging.
20. The method of claim 19, wherein the packaged antimicrobial
elastomeric article is able to reduce the number of microorganisms
present on a surface by at least 4 log.sub.10 within 5 minutes of
being contacted by the antimicrobial elastomeric article for at
least 4 weeks following opening the package to ambient atmospheric
conditions.
21. The method of claim 1, wherein the elastomeric article is
selected from the group consisting of gloves, condoms, probe
covers, and catheters.
22. An antimicrobial elastomeric article according to claim 1.
23. A packaged antimicrobial elastomeric article according to claim
15.
24. A method for preparing an antimicrobial elastomeric article,
comprising: exposing an elastomeric article to an environment
comprising about 10.3 g/m.sup.3 or less absolute humidity; and
coating the elastomeric article with an antimicrobial coating
composition to form an antimicrobial elastomeric article; wherein
the antimicrobial elastomeric article reduces the number of
microorganisms present on a surface by at least 4 log within 5
minutes of being contacted by the antimicrobial elastomeric
article.
25. A method for preparing an antimicrobial elastomeric article,
comprising: coating the elastomeric article with an antimicrobial
coating composition to form an antimicrobial elastomeric article;
and exposing the antimicrobial elastomeric article to an
environment comprising about 10.3 g/m.sup.3 or less absolute
humidity; wherein the antimicrobial elastomeric article reduces the
number of microorganisms present on a surface by at least 4 log
within 5 minutes of being contacted by the antimicrobial
elastomeric article.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to methods of
preparing antimicrobial elastomeric articles that include an
elastomeric article having an antimicrobial coating provided
thereon. The antimicrobial elastomeric articles exhibit enhanced
ability to reduce or eliminate microbes that come in contact with
the article. Certain aspects of the invention are further directed
to methods of packaging the antimicrobial elastomeric articles,
where the packaged antimicrobial articles exhibit antimicrobial
effectiveness for an extended period of time as compared to
unpackaged antimicrobial articles. Antimicrobial elastomeric
articles and packaged antimicrobial elastomeric articles prepared
in accordance with the methods of the present invention are also
provided.
[0003] 2. Description of the Related Art
[0004] Gloves are used regularly in clinical and hospital
environments by healthcare workers as personal protective
equipment. While medical gloves are primarily used to protect the
individual wearing the gloves, they also prevent transfer of
microorganisms from the healthcare worker to the patient. However,
cross contamination can still occur, especially if a healthcare
worker contacts a non-sterile surface (e.g., a bedrail) while
wearing a pair of gloves, and then contacts the patient without
first changing into a new pair of gloves. This scenario can lead to
the transfer of microorganisms from the non-sterile surface to a
susceptible patient, which may result in an undesirable nosocomial
(or "hospital-acquired") infection. Infections are considered
nosocomial if they first appear 48 hours or more after hospital
admission or within 30 days after discharge.
[0005] About 1.7 million patients get sick in hospitals each year
from infections they acquired while in the hospital. Of those 1.7
million, approximately 100,000 die as a result of their infection.
(Klevins et al., "Estimating Health Care-Associated Infections and
Deaths in U.S. Hospitals, 2002," Public Health Reports Vol. 122
(March/April 2007)). In order to combat nosocomial infections, the
CDC is promoting a campaign based on preventing infections,
diagnosing and treating infections appropriately, using antibiotics
wisely, and preventing transmission of microbes. Specific
recommendations related to the prevention of infection transmission
include having health care providers and personnel keep their hands
clean at all times. However, in many hospitals there is poor
adherence to hand hygiene guidelines. Healthcare workers face many
obstacles in their attempt to keep clean hands. They might not be
able to find a sink or a replacement pair of gloves, they have
limited time between patients, and after washing their hands as
many as 30 times during a work shift they may have serious problems
with skin irritation and dryness.
[0006] In view of the ongoing need to minimize the risk of
nosocomial infections, several approaches have been developed.
[0007] U.S. Published Patent Application No. US 2005/0186258
describes elastomeric articles coated by antimicrobial compositions
and protected by water-resistant packaging. The antimicrobial
gloves are useful in methods for reducing nosocomial infection by
Gram positive bacteria, Gram negative bacteria, fungi, and viruses.
The antimicrobial gloves may be packaged to maintain quick-kill
activity against microbes, even after extended storage. The
packaging protects the antimicrobial activity of a glove during
storage and transportation by shielding the glove from warm and/or
humid environments.
[0008] U.S. Published Patent Application No. US 2007/0104766
describes a surface treatment for elastomeric articles such as
medical gloves coated with a water-based coating formulation having
antimicrobial agent(s) therein. The coating includes a
controlled-release matrix having a blend of a hydrophilic polymer
and a hydrophobic component.
[0009] There is a need in the art for antimicrobial elastomeric
articles that are useful for reducing the occurrence of nosocomial
infections, for example, by providing a quick kill of
microorganisms that contact the article.
SUMMARY OF THE INVENTION
[0010] The present invention meets the unmet needs of the art, as
well as others, by providing methods for preparing antimicrobial
elastomeric articles that exhibit enhanced ability to reduce or
eliminate microbes that come in contact with the article. Also
provided are methods of packaging the antimicrobial elastomeric
articles to provide extended effectiveness for the antimicrobial
agent.
[0011] According to one aspect of the invention a method for
preparing an antimicrobial elastomeric article is provided that
includes exposing an elastomeric article to an environment
comprising about 10.3 g/m.sup.3 or less absolute humidity; coating
the elastomeric article with an antimicrobial coating composition
to form an antimicrobial elastomeric article; and exposing the
antimicrobial elastomeric article to an environment comprising
about 10.3 g/m.sup.3 or less absolute humidity. Preferably, the
antimicrobial elastomeric article reduces the initial number of
microorganisms present on a surface by at least 4 log.sub.10 within
5 minutes of being contacted by the antimicrobial elastomeric
article.
[0012] An additional aspect of the invention relates to an
antimicrobial elastomeric article prepared in accordance with the
methods of the invention.
[0013] Another additional aspect of the invention relates to an
antimicrobial elastomeric article prepared in accordance with the
methods of the invention that is provided in a packaging system
that permits the antimicrobial elastomeric article to reduce the
initial number of microorganisms present on a surface by at least 4
log.sub.10 within 5 minutes of being contacted by the antimicrobial
elastomeric article, for at least 12 weeks following packaging.
[0014] Another aspect of the invention relates to a method for
preparing an antimicrobial elastomeric article that includes
exposing the elastomeric article to an environment comprising about
10.3 g/m.sup.3 or less absolute humidity, and coating the
elastomeric article with an antimicrobial coating composition to
form an antimicrobial elastomeric article. Preferably, the
antimicrobial elastomeric article reduces the number of
microorganisms present on a surface by at least 4 log.sub.10 within
5 minutes of being contacted by the antimicrobial elastomeric
article.
[0015] According to a further aspect, the invention relates to a
method for preparing an antimicrobial elastomeric article that
includes coating the elastomeric article with an antimicrobial
coating composition to form an antimicrobial elastomeric article,
and exposing the antimicrobial elastomeric article to an
environment comprising about 10.3 g/m.sup.3 or less absolute
humidity. Preferably, the antimicrobial elastomeric article reduces
the number of microorganisms present on a surface by at least 4
log.sub.10 within 5 minutes of being contacted by the antimicrobial
elastomeric article.
[0016] Other novel features and advantages of the present invention
will become apparent to those skilled in the art upon examination
of the following or upon learning by practice of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention relates generally to methods of
preparing antimicrobial elastomeric articles that include an
elastomeric article having an antimicrobial coating provided
thereon. The antimicrobial elastomeric articles prepared using the
methods exhibit enhanced ability to reduce or eliminate microbes
that come in contact with the articles. Certain aspects of the
invention are further directed to methods of packaging the
antimicrobial elastomeric articles, where the packaged
antimicrobial articles exhibit antimicrobial effectiveness for an
extended period of time as compared to unpackaged antimicrobial
articles. Antimicrobial elastomeric articles and packaged
antimicrobial elastomeric articles prepared in accordance with the
methods of the present invention are also provided.
[0018] The present invention was designed to mitigate the risk of
cross contamination of microorganisms, particularly when used in a
medical environment, although use in other environments, including
laboratories and cleanroom facilities, is also envisioned. The
antimicrobial elastomeric articles preferably exhibit quick-kill
ability when contacted by a contaminated surface. "Quick-kill"
refers to the ability to reduce the number of microorganisms
present on a surface within 5 minutes of contact by a 4 log.sub.10
reduction or greater, preferably a 4.2 log.sub.10 reduction or
greater, and more preferably a 4.5 log.sub.10 reduction or greater.
According to some aspects, the reduction in microorganisms is also
evaluated following accelerated aging carried out in accordance
with ASTM D 6319-00a.sup..epsilon.3, Test Method D 573. Preferably,
the antimicrobial coating maintains this level of antimicrobial
efficacy throughout the lifetime of the product, such as at least 6
months, preferably at least one year, more preferably at least two
years, and most preferably at least three years, which includes
transportation and storage shelf-life.
[0019] However, maintaining the antimicrobial efficacy over
extended periods presents a challenge. In prior applications, the
antimicrobial agent tended to migrate from the outer surface of the
elastomeric article into the body of the article over time, causing
a decrease in efficacy. The present invention relates to new
methods for preparing antimicrobial elastomeric articles, and
methods for packaging the antimicrobial elastomeric articles to
maintain quick-kill ability. Without wishing to be bound by theory,
this migration was most likely facilitated by exposure of the
antimicrobial elastomeric article to moisture, which acts as a
vehicle for the diffusion of the antimicrobial agent into the body
of the elastomeric article. This migration leads to decreased
antimicrobial efficacy at the time of use. Reduction in
antimicrobial efficacy may alleviated by the use of the inventive
coating and packaging methods, resulting in the inventive
antimicrobial elastomeric articles.
[0020] The antimicrobial coating compositions, antimicrobial
elastomeric articles, and packaging for antimicrobial elastomeric
articles are described in greater detail below.
Antimicrobial Coating
[0021] The antimicrobial elastomeric articles are coated with an
antimicrobial coating, where the antimicrobial coating provides
antimicrobial efficacy to the elastomeric article. Preferably, the
antimicrobial coating includes one or more antimicrobial agents in
a controlled-release matrix, where the matrix may include a blend
of at least one hydrophilic polymer and at least one hydrophobic
oligomer. The antimicrobial coating composition may be beneficially
formulated as a water-based antimicrobial coating composition in
order to avoid issues that arise when handling solvents, although
elastomer-compatible, solvent-based formulations are also
envisioned.
[0022] The antimicrobial elastomeric articles are capable of
killing or restricting the growth of one or more of the following
microbes: coagulase-negative Staphylococci, Enterococci, fungi,
Candida albicans, Staphylococcus aureus, Enterobacter species,
Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus
viridans, Escherichia coli, Klebsiella pneumoniae, Proteus
mirabilis, Pseudomonas aeruginosa, Acinetobacter baumannii,
Burkholderia cepacia, Varicella, Clostridium difficile, Clostridium
sordellii, Hepatitis A, Hepatitis B, Hepatitis C, HIV/AIDS,
methicillin-resistant Staphylococcus aureus (MRSA), mumps,
norovirus, parvovirus, poliovirus, rubella, SARS, S. pneumoniae
(including drug resistant forms), vancomycin-intermediate
Staphylococcus aureus (VISA), vancomycin-resistant Staphylococcus
aureus (VRSA), and vancomycin-resistant Enterococci (VRE).
Preferably, the antimicrobial elastomeric articles have
"quick-kill" capabilities against a broad spectrum of
microorganisms. "Quick-kill" refers to the ability to reduce the
number of microorganisms present on a surface within 5 minutes of
contact by a 4 log.sub.10 reduction or greater, preferably a 4.2
log.sub.10 reduction or greater, and more preferably a 4.5
log.sub.10 reduction or greater.
[0023] Antimicrobial agents that may be used in the antimicrobial
coating may include any agent capable of killing or inhibiting the
growth of bacteria, fungi, viruses and/or parasites. For example,
suitable antimicrobial agents include, without limitation, one or
more of the following agents: biguanides (e.g., chlorhexidine
digluconate (CHG), chlorhexidine diacetate, chlorhexidine
dihydrochloride, chlorhexidine diphosphanilate, poly(hexamethylene
biguanide) (PHMB)), rifampin, minocycline, silver compounds (silver
chloride, silver oxide, silver sulfadiazine), triclosan, quaternary
ammonium compounds (e.g., benzalkonium chloride, tridodecyl methyl
ammonium chloride, didecyl dimethyl ammonium chloride, chloroallyl
hexaminium chloride, benzethonium chloride, methylbenzethonium
chloride, cetyl trimethyl ammonium bromide, cetyl pyridinium
chloride, dioctyldimethyl ammonium chloride), iron-sequestering
glycoproteins (e.g., lactoferrin, ovotransferrin/conalbumin),
cationic polypeptides (e.g., protamine, polylysine, lysozyme),
surfactants (e.g., SDS, Tween-80, surfactin, Nonoxynol-9) and zinc
pyrithione. Further preferred antimicrobial agents include
broad-spectrum antibiotics (quinolones, fluoroquinolones,
aminoglycosides and sulfonamides), and antiseptic agents (iodine,
methenamine, nitrofurantoin, validixic acid). The preferred
antimicrobial agents for a quick-kill application are chlorhexidine
digluconate (CHG), chlorhexidine diacetate, chlorhexidine
dihydrochloride, chlorhexidine diphosphanilate, and
poly(hexamethylene biguanide) (PHMB). It is considered to be within
the ability of one skilled in the art to determine the type of
antimicrobial agent and amount necessary to achieve adequate levels
of antimicrobial activity against target microbes. Preferably, the
antimicrobial agent covers at least 85% of the outside surface of
the elastomeric article, more preferably 90%, even more preferably
95%, and most preferably covers at least 99.8% of the outside
surface area of the elastomeric article.
[0024] The antimicrobial agent can be present in an amount ranging
from 0.5% to 85% by weight of total solids of the antimicrobial
coating composition, more preferably from 1.0% to 75% by weight of
total solids, and most preferably from 2.5% to 60% by weight of
total solids. Chlorhexidine is the most preferred antimicrobial
agent. The minimum concentration of chlorhexidine at the surface of
the elastomeric article is preferably greater than 7.6
.mu.g/cm.sup.2 in order to provide a 4-log efficacy against a broad
spectrum of microbes.
[0025] The term "hydrophilic polymer" is used describe polymers or
copolymers that are water soluble or water-dispersible; anionic,
cationic, or nonionic; and crosslinked or noncrosslinked.
Hydrophilic polymers usually include functional groups such as
hydroxyl, amine, amide, ether, and other functional groups with a
high affinity for water. Examples of hydrophilic polymers include,
but are not limited to, poly(vinyl alcohol, polyesters,
polyacrylates, polyethers such as polyethylene glycol and
polypropylene glycol, and cellulose and cellulose derivatives, such
as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxy ethyl
methyl cellulose, and hydroxy propyl methyl cellulose. The
hydrophilic polymer should also have good film-forming, binding,
and adhesive properties. The preferred hydrophilic polymers are
acrylic-based copolymers that include cationic dimethyl aminoalkyl
units. This offers better water permeability to the resulting
films. The preferred hydrophilic polymer is a copolymer of ethyl
acrylate, methyl methacrylate and a low content of methacrylic acid
ester with quaternary ammonium groups, sold as Eudragit.RTM. RS 30D
by Evonik Inc. The hydrophilic polymer is present in amounts
ranging from 0.5% to 99% by weight of total solids, more preferably
present in an amount ranging from 1.0% to 75%, and most preferably
ranging from 2.0% to 60% by weight of total solids.
[0026] The term "hydrophobic oligomer" is used to describe low to
medium molecular weight polymers or copolymers that offer water
resistance and aid in the film forming capabilities of the
hydrophilic polymer. Examples of hydrophobic oligomers include, but
are not limited to, fluorinated oligomers, chlorinated oligomers,
short chain alkanes, silicones, and paraffin waxes. The hydrophobic
oligomer is preferably dispersible in water; therefore paraffin wax
is a preferred hydrophobic oligomer. The paraffin wax is a
saturated hydrocarbon derived from petroleum with a chain length of
25-30 carbons. Non-ionic paraffin dispersions are preferred, such
as Michem.RTM. Lube 743 (ML 743), sold by Michelman Inc. The
hydrophobic oligomer can be present in amounts ranging from 0.5% to
99% by weight of total solids, more preferably present in an amount
ranging from 1.0% to 55%, and most preferably 1.5% to 40% by weight
of total solids.
[0027] Additional ingredients, such as wetting agents and
antifoaming agents, may also be added to the formulation to ensure
that the antimicrobial properties are optimized. A wetting agent is
described as an agent that improves the coating film quality by
allowing for quick spreading and uniform coverage. Wetting agents
are well known in that art. The preferred wetting agents include a
nonionic polyether dimethylpolysiloxane dispersion, sold as BYK 348
by BYK Chemie. Antifoaming agents are added to improve the dried
coating quality. The preferred antifoaming agent is ethylene
glycol-based, such as Surfynol.RTM. TG by Air Products.
Antimicrobial Elastomeric Articles
[0028] Articles according to the invention comprise an elastomeric
article having a coating with sustainable antimicrobial
activity.
[0029] The antimicrobial elastomeric articles of the present
invention are preferably provided in the form of gloves,
specifically medical gloves, and more specifically examination and
surgical gloves. However, it is considered within the ability of
those skilled in the art to prepare alternative antimicrobial
elastomeric articles other than gloves, including, but not limited
to, condoms, probe covers, dental dams, finger cots, catheters, and
the like, using the guidance provided herein.
[0030] According to some aspects of the invention, elastomeric
articles are provided that include multiple elastomeric layers,
where the multiple elastomeric layers may have the same or
different compositions. Preferred elastomers include, without
limitation, natural rubber, polyurethane, polybutadiene,
polychloroprene (Neoprene), nitrile rubber, block copolymers of
styrene and butadiene, block copolymers of styrene and isoprene,
and polyisoprene.
[0031] According to further aspects of the invention, the
elastomeric articles may be formed either with, or without, powder.
Although powder is a commonly-used donning agent, it is also
associated with allergic reactions, and therefore another aspect of
the invention relates to powder-free or substantially powder-free
antimicrobial elastomeric articles prepared in accordance with the
methods described above.
[0032] Pre-formed elastomeric articles prepared using conventional
techniques may be prepared for coating with the antimicrobial
coating formulation by storing the gloves in a controlled
environment that is desiccated or dehumidified prior to applying
the coating. The temperature of the environment may range from
about 10.degree. C. to about 30.degree. C., preferably from about
17.degree. C. to about 27.degree. C., and is most preferably about
23.degree. C. The relative humidity of the environment may range
from about 0% relative humidity to about 55% relative humidity,
preferably from about 15% relative humidity to about 50% relative
humidity, and is most preferably from about 30% relative humidity
to about 45% relative humidity. For example, an atmosphere of about
50% relative humidity or less at 23.degree. C. may be used to
prepare the elastomeric articles for the coating process.
Ultimately, and most preferably, the environment in which the
elastomeric articles are treated should have an absolute humidity
of from about 0 g/m.sup.3 to about 10.3 g/m.sup.3 or less,
regardless of the temperature, preferably from about 1.5 g/m.sup.3
to about 9.8 g/m.sup.3, more preferably from about 3.0 g/m.sup.3 to
about 9.3 g/m.sup.3, and most preferably from about 4.5 g/m.sup.3
to about 8.8 g/m.sup.3. By knowing the desired absolute humidity,
one skilled in the art is able to approximate the temperature and
relative humidity levels at a given atmospheric pressure that would
be suitable to maintain that absolute humidity in a controlled
environment. The elastomeric articles may be treated in the
desiccated/dehumidified controlled environment for a period of from
about 12 to about 48 hours, preferably from about 18 to about 36
hours, and more preferably about 24 hours. It should be noted that
controlled temperature and humidity may be provided in the vicinity
of the articles by a variety of methods. These may include, but are
not limited to, placing the articles in controlled-atmosphere
rooms, sealed packages or bags with or without desiccants provided
therein, closed boxes or totes with or without desiccants provided
therein, or other means for providing an enclosed space capable of
maintaining a desired level of temperature and humidity. Preferred
desiccants may be selected from the group consisting of silica gel,
aerogel, bentonite clay, activated alumina, nitrogen gas, and argon
gas.
[0033] The antimicrobial coating composition may be applied to the
elastomeric articles using conventional equipment and techniques
readily available to those in the field of manufacturing
elastomeric articles, including on-line and off-line techniques
such as dipping, spraying, tumbling and the like. Examples of
coating techniques are described in U.S. Pat. Pub. No. 2004/0126604
and U.S. Pat. Pub. No. 2004/0241201. For preparing surgical gloves,
a preferred method of application is off-line spraying. For the
preparation of examination gloves, a preferred on-line method of
application is dip coating, and a preferred off-line method is the
tumbling method of coating. Regardless of the particular
application technique selected, the coating is preferably applied
while the elastomeric articles are heated to 55.degree.
C..+-.5.degree. C., and the coated elastomeric article is
preferably dried at 55.degree. C..+-.5.degree. C. for about 30
minutes. The coating may be applied to the outer surface of the
elastomeric article, the inner surface of the elastomeric article,
or both the inner and outer surface of the elastomeric article. In
the context of elastomeric articles such as gloves, the "outer"
surface is the surface that comes into contact with the
environment, while the "inner" surface is the surface that is
primarily in contact with the user wearing the glove.
[0034] After the elastomeric articles have been coated with the
antimicrobial composition and dried, the elastomeric articles may
be subjected to a follow-up treatment in a controlled environment
that is desiccated or dehumidified. The temperature of the
environment may range from about 10.degree. C. to about 30.degree.
C., preferably from about 17.degree. C. to about 27.degree. C., and
is most preferably about 23.degree. C. The relative humidity of the
environment may range from about 0% relative humidity to about 55%
relative humidity, preferably from about 15% relative humidity to
about 50% relative humidity, and is most preferably from about 30%
relative humidity to about 45% relative humidity. For example, an
atmosphere of about 50% relative humidity or less at 23.degree. C.
may be used to conduct the follow-up treatment process. Ultimately,
and most preferably, the environment in which the elastomeric
articles are treated should have an absolute humidity of from about
0 g/m.sup.3 to about 10.3 g/m.sup.3 or less, regardless of the
temperature, preferably from about 1.5 g/m.sup.3 to about 9.8
g/m.sup.3, more preferably from about 3.0 g/m.sup.3 to about 9.3
g/m.sup.3, and most preferably from about 4.5 g/m.sup.3 to about
8.8 g/m.sup.3. By knowing the desired absolute humidity, one
skilled in the art is able to approximate the temperature and
relative humidity levels at a given atmospheric pressure that would
be suitable to maintain that absolute humidity in a controlled
environment. The elastomeric articles may be treated in the
desiccated/dehumidified controlled environment for a period of from
about 12 to about 48 hours, preferably from about 18 to about 36
hours, and more preferably about 24 hours. It should be noted that
controlled temperature and humidity may be provided in the vicinity
of the articles by a variety of methods. These may include, but are
not limited to, placing the articles in controlled-atmosphere
rooms, sealed packages or bags with or without desiccants provided
therein, closed totes with or without desiccants provided therein,
or other means for providing an enclosed space capable of
maintaining a desired level of temperature and humidity.
[0035] According to some aspects of the invention, the elastomeric
articles may be subjected to either pre-treatment or post-treatment
processing in a desiccated environment, as described above, or the
elastomeric articles may be subjected to both pre-treatment and
post-treatment processing. Without wishing to be limited by theory,
it is believed that the desiccating treatment steps are useful for
maintaining quick-kill efficacy of the antimicrobial elastomeric
article following storage. Antimicrobial elastomeric articles
prepared in accordance with the processing methods described above
beneficially maintain an unexpectedly high level of antimicrobial
efficacy as compared to elastomeric articles provided with
antimicrobial coatings that are applied using prior techniques.
[0036] Following the process of coating the elastomeric article
with the antimicrobial coating composition, the elastomeric
articles may be stored in a desiccated environment until they can
be packaged, or they may directly proceed to the packaging
step.
Packaging of Antimicrobial Elastomeric Articles
[0037] The present invention provides elastomeric articles having
an antimicrobial coating thereon, where the antimicrobial
elastomeric articles exhibit quick-kill antimicrobial efficacy. In
order to maintain the efficacy of the antimicrobial elastomeric
articles following storage and transportation, the elastomeric
articles may be packaged. The packaging preferably maintains a low
level of humidity in the environment surrounding the antimicrobial
elastomeric article.
[0038] Any packaging material and/or technique that is capable of
providing a low vapor-permeable package may be used in accordance
with the present invention. Suitable materials that may be useful
for packaging elastomeric articles include, but are not limited to,
aluminum foil (or foils formed from other metals/alloys),
polyethylene, and nylon-based multi-layer films, as well as
laminates containing different film layers, such as aluminum/nylon
laminates. One preferred package design consists of aluminum foil
that contains the internal atmosphere of the packaging, with the
elastomeric articles inside, via a hermetic seal. According to some
aspects, the packaging material provides a 100% barrier against
transmission of humidity into the package (i.e., 0% water vapor
transmission).
[0039] Regardless of the type of elastomeric article or the
specific packaging technique, before the outer package is sealed,
preferably as much humidity- or moisture-containing air as possible
is removed from the package to provide a reduced-humidity
environment for the elastomeric article provided within the
package, as compared to the environment outside the package. This
may be done by using one or more of the following techniques:
[0040] (a) Removing humidity- or moisture-containing air from an
enclosed compartment (or chamber) in which an elastomeric article,
which may optionally be wrapped in an inner packet, is placed. The
elastomeric article may be sandwiched between a top web film and a
bottom web film (which may be provided, for example, in the form of
a shallow tray) before sealing the film with heat and pressure to
form the outer package. Air may be sucked out from the enclosed
compartment (or chamber) by connecting it to a vacuum pump or other
apparatus before sealing the outer package. This method of
packaging is referred to as thermo "form fill seal" packaging.
[0041] (b) Mechanically squeezing out humidity- or
moisture-containing air from the unsealed package including the
elastomeric article, which optionally may be wrapped in an inner
packet. The elastomeric article then may be sandwiched between a
top web film and a bottom web film to form the unsealed package
before sealing the package with heat and/or pressure. This method
of packaging is referred to as "platen seal" packaging.
[0042] (c) Flushing air out of the unsealed package with an inert
gas, such as nitrogen, before sealing the package. This may be done
using a "form fill seal" packaging machine where inert gas is used
instead of applying a vacuum to remove the humidity- or
moisture-containing air.
[0043] Any packaging material and/or technique that is capable of
maintaining a reduced-humidity environment within the package may
be used in accordance with the present invention.
[0044] The package containing the antimicrobial elastomeric article
may also optionally include a desiccant material, particularly when
the packaging material does not provide a 100% barrier against
transmission of humidity. Desiccants that may be incorporated into
the packaging used in the present invention may include, but are
not limited to, silica gel, aerogel, bentonite clay, activated
alumina, nitrogen gas, and argon gas. The dessicant may also be
provided in the form of a vacuum-evacuated atmosphere within the
package. One skilled in the art can also develop other means to
control the atmosphere inside the packaging by either evacuating
the inside of the packaging or to fill the packaging with an inert
atmosphere such as nitrogen or argon.
[0045] Without wishing to be bound by theory, it is believed that a
low vapor-permeable package maintains the high level of
antimicrobial efficacy of the antimicrobial elastomeric articles
formed using the methods described above by minimizing the presence
of water vapor in the environment surrounding the article. It is
believed that the antimicrobial agent has a tendency to be absorbed
into the body of the elastomeric article when in the presence of
water. By limiting the amount of water vapor, less antimicrobial
agent is absorbed into the elastomeric article, leaving more of the
antimicrobial agent available at the surface of the article for the
desired "quick-kill" ability at the surface of the elastomeric
article. Preferably, the relative humidity inside the packaging
system is below about 50% relative humidity. According to some
aspects of the invention, even lower relative humidity may be
maintained inside the package, such as less than about 40%,
preferably less than about 30%. and more preferably less than about
10% or 5% relative humidity.
[0046] According to further aspects, the antimicrobial elastomeric
articles that are packaged at ambient temperatures and up to 50%
relative humidity (RH) may maintain quick-kill antimicrobial
efficacy for at least 4 weeks following opening the package and
exposing the contents to atmospheric conditions, preferably for at
least 6 weeks, and more preferably for at least 8 weeks following
opening the package.
[0047] It will be appreciated that package materials, desiccant,
and pouch designs used for antimicrobial elastomeric articles in
accordance with the invention can vary. For example, the amount of
desiccant used can depend on the number of gloves being packed in a
particular package, the barrier level provided by the packaging
materials, and the environmental conditions during packaging.
[0048] Using these conditions, a quick-kill improvement of 1-log
reduction on a five-minute exposure time is achieved, a 2-log
reduction on a five-minute exposure time is preferred, and at least
a 2-log reduction after a one-minute exposure time is more
preferred. Using these conditions, a quick-kill efficacy of 4-log
reduction on a five-minute exposure time is most preferred.
[0049] These and other aspects of the invention are further
described in the non-limiting Examples set forth below.
EXAMPLES
Example 1
[0050] Example 1 demonstrates that efficacy of an antimicrobial
coating that utilizes CHG as the active antimicrobial component.
The coating consists of hydrophilic polymer and hydrophobic
oligomer that produce a film containing the active agent. A wetting
agent and low foaming agent are also added to the formulation to
provide good coating quality.
TABLE-US-00001 TABLE 1 Formulation 1-1 Concentration (%) Dry %
Amount (g) CHG (20%) 7.50 3.75 840.00 Wetting Composition 0.10
0.0075 11.20 (3%) Eudragit .RTM. RS 30D 4.00 3.00 448.00 (30%) ML
743 (32%) 3.13 2.50 350.00 DI Water -- -- 9550.80 Total 14.73
11200
[0051] Wetting composition: A 3% solution was prepared by adding 10
g of Surfynol.RTM. TG and 5 g of BYK-348 to 485 g of deionized
water (DI water). The mixture was stirred for 20 minutes to achieve
the desired concentrations of 2% Surfynol.RTM. TG and 1% of
BYK-348.
[0052] Formulation 1-1: 11.20 g of wetting composition was added to
9550.80 g of DI water. This solution is mixed for at least 10
minutes. 840.00 g of CHG, 448.00 g of Eudragit.RTM. RS 30D, and
350.00 g of ML 743 are added individually to the solution and in
that respective order. After the addition of each component, the
solution is mixed for at least 10 minutes before the next component
is added. Upon complete addition, the solution is stirred for an
additional 10 minutes.
[0053] Glove Treatment: The nitrite gloves were subjected to a
pretreatment process that involved the storage of gloves in a
sealed tote that maintained a desiccated environment surrounding
the gloves, wherein the environmental temperature was 23.degree. C.
and the relative humidity was 50%. The relative humidity level was
achieved by placing a dessicant in the tote. The gloves remained in
the desiccated environment for at least 24 hours prior to coating
application. Following the pretreatment of the gloves, the surface
of the glove was treated with antimicrobial coating using a spray
coating technique. The gloves were heated to 55.degree. C. during
the application process. Following the application of the coating,
the coated gloves were dried at 55.degree. C. for 30 minutes, then
immediately placed into a desiccated environment for at least 24
hours.
[0054] Antimicrobial Activity: The antimicrobial activity of sample
1-1 was tested before and after aging against E. coli and MRSA with
a 5 minute exposure time:
TABLE-US-00002 TABLE 2 Sample 1-1 E. Coli MRSA Fresh >5.37
>4.56 After Aging (7 days @ 70.degree. C.) 4.72 4.77
[0055] The test results show that with a single antimicrobial
agent, antimicrobial activities can be maintained above 4 log
reduction of both gram positive and gram negative microbes after
aging for 7 days at 70.degree. C.
Example 2
[0056] Example 2 demonstrates the conditions needed to provide a
stable antimicrobial coating on the surface of the nitrile glove.
The coating composition and formulation fabrication remained the
same as describe in Example 1. Sample 2-1 describes coated gloves
that were stored in desiccated environments (described above in
Example 1) before and after the application of the antimicrobial
coating. Samples 2-2 and 2-3 represent coated gloves that were pre-
and post-conditioned (using the technique described above in
Example 1), respectively. Sample 2-4 describes coated gloves that
were not desiccated before or after application of the
antimicrobial coating. Samples 2-1 through 2-4 were tested before
and after conditioning against E. coli and MRSA with a 5 minute
exposure time.
TABLE-US-00003 TABLE 3 E. coli MRSA Aged Aged Sample ID Fresh
(70.degree. C., 7 days) Fresh (70.degree. C., 7 days) Sample 2-1
5.37 4.37 4.56 4.24 Sample 2-2 4.54 4.01 4.24 4.00 Sample 2-3 4.27
4.57 4.35 4.13 Sample 2-4 4.59 1.24 5.42 2.00
[0057] The test results demonstrate the need for conditioning of
the gloves before and/or after the gloves are treated with the
antimicrobial coating. The antimicrobial efficacy is believed to be
lost due to the phenomenon described in U.S. Publ. Appl. No.
2007/0104766. This describes that effect of moisture on the
antimicrobial glove and how the antimicrobial agent will migrate
from the surface of the glove that is facilitated by the presence
of water in the nitrile glove and in the surrounding environment.
The antimicrobial efficacy is not affected when the gloves are
tested after being freshly coated. However, when sample 2-4 is
exposed to accelerated aging conditions following ASTM D
6319-00a.sup..epsilon.3, Test Method D 573, the antimicrobial
efficacy decreases. Samples 2-1, 2-2, and 2-3 are able to maintain
the antimicrobial efficacy because of the desiccated storage
conditions pre- and/or post-coating.
Example 3
[0058] Example 3 demonstrates the stability of the antimicrobial
glove against relative humidity levels at ambient temperatures. The
coating composition, formulation fabrication, and coating
application method remained the same as described in Example 1.
Sample 3-1 describes antimicrobial-coated gloves that were exposed
to 23.degree. C. with a relative humidity of 45%. Sample 3-2
describes antimicrobial-coated gloves that were exposed to
23.degree. C. with a relative humidity of 55%. Sample 3-3 describes
antimicrobial-coated gloves that were exposed to 23.degree. C. with
a relative humidity of 75%. All samples were tested after one and
two weeks exposure to the temperature and humidity levels.
Antimicrobial efficacy was recorded against E. coli after a 5
minute exposure time.
TABLE-US-00004 TABLE 4 E. coli Log Reduction Sample Sample
Condition 1 Week 2 week Sample 3-1 23.degree. C., 45% RH 5.38 4.7
Sample 3-2 23.degree. C., 55% RH 3.93 2.59 Sample 3-3 23.degree.
C., 75% RH 3.08 1.39
[0059] The test results shown in Table 4 demonstrate the effect of
humidity on the antimicrobial coated glove. At ambient
temperatures, the antimicrobial glove starts to lose efficacy when
the relative humidity is approximately 55% or greater. While not
wishing to be bound by theory, it is believed that this humidity
level causes the migration of CHG into the glove substrate from the
antimicrobial coating.
Example 4
[0060] Example 4 demonstrates the need for robust packaging to
maintain the antimicrobial efficacy of the antimicrobial coated
glove. The coating composition, formulation fabrication, and
coating application method remained the same as described in
Example 1. Antimicrobial gloves were packed into two packaging
prototypes. The prototypes contained the antimicrobial coated
gloves and the prototypes were subjected to outside conditions
meant to simulated real world conditions experienced by medical
glove products. Sample 4-1 is a control glove that was not
packaged. Sample 4-2 is a packaging prototype comprised of Amcor
aluminum foil laminate packaging containing antimicrobial-coated
gloves and desiccant. Sample 4-3 is a packaging prototype made from
the same material as described in Sample 4-2, but this sample
contained only antimicrobial-coated gloves and no desiccant. The
samples were tested against E. coli and MRSA after exposure to
45.degree. C. and 85% relative humidity for up to 16 weeks.
TABLE-US-00005 TABLE 5 Time Points Week 2 Week 4 Week 6 Week 8 Week
12 Week 16 E. Coli MRSA E. Coli MRSA E. Coli MRSA E. Coli MRSA E.
Coli MRSA E. Coli MRSA Sample LR LR LR LR LR LR LR LR LR LR LR LR
Sample 4-1 0 0 -- -- -- -- -- -- -- -- -- -- Sample 4-2 4.47 5.20
4.47 4.42 4.49 4.93 4.57 4.70 4.64 4.50 4.57 4.42 Sample 4-3 4.47
4.68 4.47 4.42 4.61 5.07 4.57 4.59 4.50 4.19 4.79 4.68
[0061] The results show that the antimicrobial efficacy is
maintained above 4 log reduction against E. coli and MRSA after 5
minutes of exposure time when packaged into an aluminum foil pouch
that is hermetically sealed. A control glove was analyzed under
similar conditions without packaging protection. The control gloves
lost antimicrobial efficacy during the exposure period.
Example 5
[0062] Example 5 demonstrates the open package stability of the
antimicrobial-coated gloves after being packaged and exposed to
conditions described in Example 4. The coating composition,
formulation fabrication, and coating application method remained
the same as described in Example 1. The packaging of the gloves and
subsequent exposure to 45.degree. C. and 85% relative humidity were
the same as described in Example 4. Sample 5-1 is a packaging
prototype comprised of Amcor aluminum foil laminate packaging
containing antimicrobial-coated gloves and desiccant. Sample 5-2 is
a packaging prototype made from the same material as described in
Sample 5-1, but this sample contained only antimicrobial-coated
gloves and no desiccant. Following exposure to 45.degree. C. and
85% relative humidity, the packages were opened and maintained at
ambient room conditions. Each sample was tested against E. coli and
MRSA to show the maintenance of 4 log reduction in microbes after 5
minutes exposure time under these conditions.
TABLE-US-00006 TABLE 6 Open Pouch Efficacy-4 weeks Sample E. coli
MRSA Sample 5-1 4.24 4.70 Sample 5-2 4.00 4.51
[0063] The results demonstrate the open pouch stability of the
antimicrobial-coated gloves at up to 4 weeks after the
antimicrobial-coated gloves have been exposed to simulated
transportation conditions. This is an important simulation of
actual product exposure through the supply chain to show that the
final user is receiving a glove that possesses the efficacy to kill
a broad spectrum of microbes.
Example 6
[0064] Example 6 demonstrates the minimum concentration of CHG
needed to achieve 4 log efficacy in 5 minutes exposure time on an
antimicrobial-coated glove. The formulation fabrication and coating
application were the same as described in Example 1. The
concentration of the active component, CHG, was varied in the
formulation. These formulations were then applied to the gloves and
the concentration of CHG needed on the coated glove in order to
achieve at least 4 log efficacy was measured. The concentration of
CHG was measured using UV-Visible spectroscopy with the assistance
of a sodium hypobromite indicator. CHG was extracted from the glove
using water and the unknown concentration was calculated versus a
predetermined standard curve. The antimicrobial efficacy after an
exposure time of 5 minutes was determined against E. coli and
MRSA.
TABLE-US-00007 TABLE 7 CHG Concentration Log Reduction
(.mu.g/cm.sup.2) E. coli MRSA 2.09 1.67 3.08 7.63 4.18 4.16 11.90
4.72 4.06
[0065] The data demonstrates that about 7.6 .mu.g of CHG is needed
to offer 4 log antimicrobial efficacy against a broad spectrum of
microbes.
Example 7
[0066] Example 7 describes the determination of surface area
coverage by the antimicrobial agent on a medical glove. This was
determined using an indicator comprised of cetyl trimethylammonium
bromide (CTAB), mixed with water. Sodium hypobromite was added to
solution and kept at approximately 37.degree. C. An antimicrobial
glove that was fabricated as described in Example 1 was then dipped
into the indicator solution. The areas on the glove where CHG was
coated turned a dark red color and the areas on the glove that were
not coated on the glove remained the same color as the glove. These
uncoated areas were measured, totaled, and it was calculated that
greater that 99% of the glove is coated with CHG.
[0067] It will, of course, be appreciated that the above
description has been given by way of example only and that
modifications in detail may be made within the scope of the present
invention.
[0068] Throughout this application, various patents and
publications have been cited. The disclosures of these patents and
publications in their entireties are hereby incorporated by
reference into this application, in order to more fully describe
the state of the art to which this invention pertains.
[0069] The invention is capable of considerable modification,
alteration, and equivalents in form and function, as will occur to
those ordinarily skilled in the pertinent arts having the benefit
of this disclosure.
[0070] While the present invention has been described for what are
presently considered the preferred embodiments, the invention is
not so limited. To the contrary, the invention is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the detailed description provided
above.
* * * * *