U.S. patent application number 13/293755 was filed with the patent office on 2012-03-08 for biostatic polymer.
This patent application is currently assigned to Novapharm Research (Australia) PTY LTD. Invention is credited to Steven Kritzler.
Application Number | 20120058077 13/293755 |
Document ID | / |
Family ID | 36776870 |
Filed Date | 2012-03-08 |
United States Patent
Application |
20120058077 |
Kind Code |
A1 |
Kritzler; Steven |
March 8, 2012 |
BIOSTATIC POLYMER
Abstract
Methods and compositions effective for at least a week for
prevention of microbial colony growth on a surface, for example an
inanimate surface, where the surface is covered with a dry or
substantially dry film formed from a composition comprising a
polyvinyl alcohol and a quaternary ammonium compound. The film may
be formed in situ by coating the surface with a solution or
emulsion comprising a polyvinyl alcohol and a quaternary ammonium
compound and then causing or allowing it to dry or substantially
dry.
Inventors: |
Kritzler; Steven; (Cronulla,
AU) |
Assignee: |
Novapharm Research (Australia) PTY
LTD
Rosebery
AU
|
Family ID: |
36776870 |
Appl. No.: |
13/293755 |
Filed: |
November 10, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13026327 |
Feb 14, 2011 |
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13293755 |
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11883492 |
Aug 1, 2007 |
7888404 |
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PCT/AU2006/000130 |
Feb 2, 2006 |
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13026327 |
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Current U.S.
Class: |
424/78.27 ;
427/385.5; 427/389.7; 427/393.5; 525/56 |
Current CPC
Class: |
C08K 5/19 20130101; A01N
33/12 20130101; A01N 33/12 20130101; C09D 129/04 20130101; C08K
5/0058 20130101; C09D 129/04 20130101; A01N 33/12 20130101; C08K
5/19 20130101; A01N 25/24 20130101; A01N 33/12 20130101; A01N
2300/00 20130101; C08K 5/19 20130101; A01N 25/10 20130101; A01N
25/34 20130101; A01N 25/24 20130101; A01N 25/10 20130101; C08L
29/04 20130101 |
Class at
Publication: |
424/78.27 ;
525/56; 427/393.5; 427/389.7; 427/385.5 |
International
Class: |
A01N 33/12 20060101
A01N033/12; C08F 116/06 20060101 C08F116/06; B05D 3/00 20060101
B05D003/00; A01P 1/00 20060101 A01P001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2005 |
AU |
AU 2005900444 |
Claims
1. A method effective for at least a week for prevention of
microbial colony growth on an inanimate surface which is a plastic,
metal, glass or ceramic surface, comprising the step of covering
the surface with a dry film consisting essentially of a biostatic
complex formed by a polyvinyl alcohol with a quaternary ammonium
compound, wherein the biostatic complex is effective to reduce a
population of P. Aeruginosa to less than 1 log within 24 hours, as
tested according to the method of ASTM E2180-01, and to maintain
the population at less than 1 log for at least 7 days, as tested
according to the method of ASTM E2180-01.
2. The method according to claim 1 wherein the dry film is formed
in situ by coating the surface with a solution or emulsion
consisting essentially of a polyvinyl alcohol with a quaternary
ammonium compound, and then causing or allowing the coating to
dry.
3. The method according to claim 1 wherein the biostatic complex is
characterized by a shift in the infrared spectrum of a vinyl
alcohol OH group peak from 3296 cm.sup.-1 to 3346 cm.sup.-1.
4. The method according to claim 1 wherein the polyvinyl alcohol
has a hydrolysis range of greater than 96 mole %.
5. The method according to claim 1 wherein the quaternary ammonium
compound comprises from 0.5 to 75 wt. % of the dried film
composition.
6. The method according to claim 1 wherein the quaternary ammonium
compound is an alkyl benzalkonium compound.
7. (canceled)
8. A composition for prevention of microbial colony growth on an
inanimate surface which is a plastic, metal, glass or ceramic
surface, comprising a dry film consisting essentially of a
biostatic complex formed by a polyvinyl alcohol with a quaternary
ammonium compound, wherein the biostatic complex is effective to
reduce a population of P. Aeruginosa to less than 1 log within 24
hours, as tested according to the method of ASTM E2180-01, and to
maintain the population at less than 1 log for at least 7 days, as
tested according to the method of ASTM E2180-01.
9. The composition according to claim 8 wherein the polyvinyl
alcohol has an average degree of hydrolysis of greater than 96 mole
%.
10. The composition according to claim 8 wherein the quaternary
ammonium compound comprises from 0.5 to 75 wt. % of the dried film
composition.
11. The composition according to claim 8 wherein the quaternary
ammonium compound is an alkyl benzalkonium compound.
12. (canceled)
13. The composition according to claim 8 wherein the biostatic
complex is in a solution or emulsion prior to formation of the dry
film.
14. (canceled)
15. The method according to claim 1, wherein the dry film further
consists essentially of a surfactant which does not inactivate the
quaternary compound.
16. The method according to claim 15, wherein the surfactant is a
non-ionic, cationic or amphoteric surfactant.
17. (canceled)
18. The method according to claim 2, wherein the solution or
emulsion further includes a surfactant which does not inactivate
the quaternary compound.
19. The method according to claim 18, wherein the surfactant is a
non-ionic, cationic or amphoteric surfactant.
20. (canceled)
21. The composition according to claim 8, wherein the dry film
further consists essentially of a surfactant which does not
inactivate the quaternary compound.
22. The composition according to claim 21, wherein the surfactant
is a non-ionic, cationic or amphoteric surfactant.
23. (canceled)
24. The composition according to claim 13, wherein the solution or
emulsion further includes a surfactant which does not inactivate
the quaternary compound.
25. The composition according to claim 24, wherein the surfactant
is a non-ionic, cationic or amphoteric surfactant.
26. (canceled)
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/026,327, filed Feb. 14, 2011, which is a continuation of
U.S. application Ser. No. 11/883,492, filed Aug. 1, 2007, which is
a national stage filing under 35 U.S.C. .sctn.371 of international
application PCT/AU2006/000130, filed Feb. 2, 2006, which was
published under PCT Article 21(2) in English.
FIELD OF THE INVENTION
[0002] This invention relates to a polymer composition which is
biostatic or biocidal, and to a method for treating a surface to
prevent microbial colony growth thereupon. The composition may be
formed into a film, and the film will resist microbiological growth
for a long period.
BACKGROUND OF THE INVENTION
[0003] Any discussion of the prior art throughout the specification
should in no way be considered as an admission that such prior art
is widely known or forms part of common general knowledge in the
field.
[0004] It is well known that infection may be transmitted from one
person to another by direct contact, by inhalation of air borne
infectious particles, or by contact with infectious fluids.
Infection is also commonly transmitted indirectly for example by
contact with a surface that has itself become infected by contact
with an infected person, or with infected airborne particles, or
fluids.
[0005] For example hospital taps are a notorious for their
potential to transmit infection and this has been to some extent
alleviated by the use of elbow lever taps. But inside hospitals
microbial agents such as bacteria, spores, viruses and fungi can
also be indirectly transmitted by staff handling instruments,
instrument sterilizing baths, door handles, and by touching many
other surfaces. Both inside and outside of hospitals infections are
spread via contact with toilet cubicle surfaces, toilet flushing
buttons/levers, toilet doorhandles, telephone handsets, lift
buttons, furniture and building surfaces, documents, and utensils
to name but a few of countless examples. Surfaces of all of these
typically harbour significant and rapidly growing colonies of
microbes, moulds and the like.
[0006] The risk of infection from such like surfaces is reduced by
regular cleaning with disinfectant solutions. However it is not
practical to wipe such surfaces sufficiently often to provide
effective disinfection.
[0007] No disinfectants for application to surfaces have been
sufficiently durable to maintain a biostatic surface for long
periods in use. Attempts to incorporate disinfectants into the
surface for slow release have either not proven sufficiently
durable, or have not been sufficiently effective or have been too
toxic or expensive and none has been commercially successful.
[0008] It is an object of the present invention to overcome or
ameliorate at least one of the disadvantages of the prior art, or
to provide a useful alternative.
BRIEF DESCRIPTION OF THE INVENTION
[0009] According to a first aspect the invention provides a method
effective for at least a week for prevention of microbial colony
growth on a surface comprising the step of covering the surface
with a dry or substantially dry film formed from a composition
comprising a polyvinyl alcohol and a quaternary ammonium compound.
Preferred embodiments of the invention are effective for at least a
week for prevention of microbial colony growth, and in some cases
many months.
[0010] According to a second aspect the invention provides a
composition effective for at least a week for prevention of
microbial colony growth on a surface comprising a dry or
substantially dry film formed from a composition containing a
complex formed between a polyvinyl alcohol and a quaternary
ammonium compound.
[0011] The present invention provides a polymeric material which
can be coated onto a surface from a solution or emulsion and dried
or allowed to dry to a dry film, although in less preferred
embodiments, the film is substantially dry but may retain some
moisture. Preferably, the surface of the film remains biostatic for
long periods.
[0012] By biostatic is meant that microbial colonies (if any) on
the surface do not grow or multiply. By "long periods" in this
context is meant a period of at least a week, preferably weeks,
months, and more preferably years.
[0013] Unless the context clearly requires otherwise, throughout
the description and the claims, the words `comprise`, `comprising`,
and the like are to be construed in an inclusive sense as opposed
to an exclusive or exhaustive sense; that is to say, in the sense
of "including, but not limited to".
[0014] In preferred embodiments a composition according to the
invention is coated onto an inanimate surface (for example a bench
top), by being wiped on as a film, or by being sprayed onto the
surface. The composition may then be wiped off the inanimate
surface and serves to (a) disinfect the surface to which it is
applied, (b) cleans the surface and (c) leave a residual
transparent residual film which is biostatic for at least a week,
and preferably many weeks. The composition need not be wiped off
and in the case of for example of an air-conditioning duct
interior, the sprayed composition may simply be left to dry. In
other preferred embodiments an article may be coated (for example
onto sheet material) by knife coating or calendering or spraying or
by dipping it into a solution or emulsion of the polymer and drying
the film or allowing the film to dry. In preferred embodiments of
the invention the quaternary ammonium compound is present in the
range of from 0.5% to 75% w/w of the dried composition.
[0015] The present inventors have discovered that a combination of
a polyvinyl alcohol with from 0.5% to 75% w/w of a quaternary
ammonium biocide results in a composition which is biostatic, that
is to say on which micro organisms do not grow.
[0016] The composition may be used to form a film with which to
coat a surface. and which is biostatic and remains so for long
periods. The combination may optionally include adhesion promoters,
vehicles, pigments and the like.
[0017] Desirably, the film forming composition contains one or more
surfactants which are selected so as not to deactivate the
quaternary ammonium compound and which due to their low surface
tension ensure thorough wetting of an underlying inanimate
substrate penetrating into any scratches or cracks. Preferred
surfactants are selected from non-ionic, cationic or amphoteric
surfactants. Conventional formulation wisdom teaches that a
combination of a surfactant with a quaternary ammonium compound
would deactivate the quaternary compound and/or dry to a sticky
surface which attracts dust and other proteinaceous residues which
have a tendency to deactivate quaternary ammonium biocides.
[0018] The present inventors have discovered that a complex is
formed between the polyvinyl alcohol and the quaternary compound
which is not sticky in the presence of efficacious levels of
quaternary compatible surfactants. Evidence for complex formation
resides in a significant shift in the infra red spectrum of a the
OH group peak from 3296 cm.sup.-1 in pure polyvinyl alcohol to 3346
cm.sup.-1 in mixtures with the quaternary ammonium biocide
indicative of very significant levels of hydrogen bonding.
[0019] In preferred embodiments the combination is prepared as an
aqueous solution which dries to a clear hard film on which micro
organisms will not grow. The solution may be applied by wiping,
brushing spraying, dipping onto an inanimate surface and drying or
allowing drying. Compositions according to the invention may be
formed into films for example on door handles, tap handles, toilet
seats, telephone handsets, air conditioning ducts, bench tops, or
the like.
[0020] The term "polyvinyl alcohol" as herein used includes all
resins made by the hydrolysis (saponification) of polyvinyl esters,
for example polyvinyl acetate. The properties of the resins vary
according to the degree of polymerization of the parent polyvinyl
ester and the extent of the hydrolysis (saponification degree). In
the case of a polyvinyl alcohol prepared from polyvinyl acetate the
structure of polyvinyl alcohol may be represented by
--CH.sub.2CHOH (CH.sub.2CHOH).sub.m--
where "1+m" is the degree of polymerization. On partial hydrolysis
proportional amounts of residual CH.sub.2COO-- groups are
distributed along the chain in place of OH and the amount of such
acetate groups expressed as a percentage is the acetate content.
Thus in polyvinyl alcohol of 70% acetate content, 30% of the
acetate groups of the original polyvinyl acetate were hydrolysed to
hydroxyl groups, and 70% remain as acetate groups. This may be
referred to as 70% acetate content or as a 30% alcohol.
[0021] In grades having above 90% alcohol (less than 10% acetate),
the polyvinyl alcohol tends to be only readily soluble in hot water
(above 90.degree. C.) although this also varies to an extent with
degree of polymerization.
[0022] The term "polyvinyl alcohol" as used herein includes all
suitable grades, degrees of saponification and degrees of
polymerization.
[0023] Polyvinyl alcohols may also be made by hydrolysing polyvinyl
esters other than acetates, and the same principles apply to the
polyvinyl alcohols so formed which may also be used in the
invention. However, preferred embodiments of the invention utilize
polyvinyl alcohol having an average degree of hydrolysis of greater
than 96 mole % hydrolysis, since such compositions are more
resistant to removal from a surface to which they are applied by
cold or warm water and are less likely to be removed from a treated
surface onto the skin by human contact.
[0024] Quaternary Ammonium Compounds for Use in the Invention
[0025] The invention has been exemplified by reference to n-alkyl
dimethyl benzyl ammonium chloride (also known as benzalkonium
chloride) as the highly preferred quaternary biocide. Alkyl benzyl
quaternary biocidal compounds are preferred; however those skilled
in the art will recognise that other biocidal quaternary ammonium
antimicrobial compounds may be used in the present invention.
[0026] It is preferred that the biocidal quaternary ammonium
antimicrobial compound is selected from the group having a general
formula:
##STR00001##
[0027] Wherein R' R'' R''' R'''' are alkyl radicals that may be the
same or different, substituted or unsubstituted, branched or
unbranched, and cyclic or acyclic. X is any anion but preferably a
halogen, more preferable chlorine or bromine
[0028] Highly preferred antimicrobial compounds are mono-long
chain, tri-short chain, tetralkyl ammonium compounds,
di-long-chain, di-short chain tetralkyl ammonium compounds and
mixtures thereof. By "long" chain is meant about C.sub.6--C.sub.30
alkyl, and by "short" chain is meant C.sub.1--C.sub.5 alkyl,
preferably C.sub.1--C.sub.3, or benzyl, or C.sub.1--C.sub.3
alkylbenzyl. Examples include monoalkyltrimethyl ammonium salts
such as cetyltrimethyl ammonium bromide (CTAB),
monoalkyldimethylbenzyl compounds or dialkylbenzyl compounds. Quat.
biocides such as chlorhexadine gluconate may be employed.
[0029] The most highly preferred compounds for use in the invention
have at least one benzyl radical which may be a substituted benzyl.
Examples include C.sub.8--C.sub.22 dimethyl benzyl ammonium
chloride, C.sub.8--C.sub.22 dimethyl ethyl benzyl ammonium chloride
and di- C.sub.6--C.sub.20 alkyl dimethyl ammonium chloride.
[0030] The quaternary ammonium compound is incorporated for broad
spectrum (gram positive and gram negative) antibacterial
properties.
[0031] Although the quaternary ammonium compound may comprise from
0.5% to 75% w/w of the dried film composition, it is preferred to
employ more than 2% w/w of the dried film composition.
[0032] Desirably the composition includes one or more surfactants
which are compatible with (i.e. do not deactivate) the quaternary
ammonium compound. Surfactants selected from non-ionic, cationic
and amphoteric surfactants are preferred for example non ionic
surfactants such as C.sub.12 to C.sub.18 straight chain alcohol or
ethoxylated alcohols or cocamine oxides. However other examples
include branch chain and aromatic ethoxylated surfactants. An
example of a suitable cationic surfactant is polyethylene
glycol-2-cocamine and an example of a suitable amphoteric
surfactant is coco-betaine.
EXAMPLES
Example 1: Manufacture of Composition According to the
Invention
[0033] A composition was manufactured having the composition shown
in table 1:
[0034] The following procedure was employed:.
[0035] About one quarter of the amount of water required (about 724
Kg) was placed into a cleaned and sanitized water jacketed mixing
tank.
[0036] The mixer was started. Polyvinyl alcohol was added
slowly
[0037] The temperature was raised to 80-90.degree. C. while
stirring
[0038] Mixing was continued for another hour or until the Polyvinyl
alcohol was dissolved at this temperature.
[0039] The tank was then cooled while mixing in the remaining
water.
[0040] The solution was cooled to below 40.degree. C. and the
TERIC.RTM. LA8 (Huntsman Corporation, fluidized detergent alcohol
alkoxylate) added.
[0041] The combination was mixed for 5 minutes and then the
quaternary compound (BARQUAT.RTM. MB-80 (Lonza, Alkyl (C.sub.14
50%, C.sub.16 10%, C.sub.12 40%) Dimethyl Benzyl Ammonium
Chloride)) was added. The combination was stirred for a further 10
mins, the pH adjusted to 7.0 and make up water added as
required.
TABLE-US-00001 TABLE 1 composition Batch size 3000 litre 3015 kg
Density 1.005 g/mL Generic name Trade name % w/w (kg) Water Water
96 2894.4 Polyvinyl alcohol generic 1.5 45.225 Alcohols,
C.sub.12-C.sub.15, TERIC LA8 0.2 6.030 ethoxylated n-Alkyl (40%
C.sub.12, BARQUAT 1.5 45.225 50% C.sub.14, 10% C.sub.16) MB-80
dimethyl benzyl ammonium chloride (80% solution) Sodium hydroxide
or NaOH (10%) or to pH 6.5-7.5 to pH 7 hydrochloric acid HCl (10%)
Water Water to 100% To 3015 kg
[0042] The polyvinyl alcohol has a degree of saponification in the
range 80%-95%, more usually about 87.5% and a viscosity of 3.0-3.7
MPa.s(cp).
[0043] The composition according to the invention was spread on a
metal (aluminum) surface using a knife coater and allowed to dry to
form a clear film. The dry film was inoculated with Pseudomonas
Aeruginosa ATCC 15442 (6.1 log concentration). After 1 hour it was
found that the population had reduced to less than 1 log. After 24
hours the population had reduced to zero. After 7 days the
population was zero. After 30 days the micro-organism population on
the surface was still zero. These tests are ongoing and the
inventors are confident that the surfaces will maintain the
bacteriostatic properties for a very long period.
[0044] The results achieved using Aspergillus Niger ATCC16404 were
the same or better showing resistance to colonization by both
bacteria and fungi.
[0045] The same results were achieved by casting films containing
only the polyvinyl alcohol and the quat in ratios of from 0.5% up
to 75%.
[0046] Compositions according to examples 2 and 3 below were also
made using the above method with similar results.
Example 2
TABLE-US-00002 [0047] Water 95.6.0% w/w Polyvinylalcohol 1.2% w/w
(low molecular weight; % hydrolysis 96.5%-99.0%) Ethoxylated
C.sub.12 to C.sub.18 straight chain alcohol 0.2% w/w Benzalkonium
chloride 3.0% w/w Adjust pH to 7.0 with NaOH or HCl Water QS
100%
Example 3
TABLE-US-00003 [0048] Water 96.0% w/w Polyvinylalcohol 1.5% w/w
(low molecular weight; % hydrolysis 96.5%-99.0%) Ethoxylated
C.sub.12 to C.sub.18 straight chain alcohol 0.2% w/w Benzalkonium
chloride 1.2% w/w Adjust pH to 7.0 with NaOH or HCl Water QS
100%
[0049] Films made from compositions according to Examples 1, 2, and
3 were all deemed to be effective for prevention of microbial
colony growth in accordance with method AOAC 955.17 after 1, 7, and
30 days.
Example 4
TABLE-US-00004 [0050] Water 77.5% w/w Polyvinylalcohol 8.0% w/w
(low molecular weight; % hydrolysis 96.5%-99.0% TERIC BL8 1.0% w/w
Benzalkonium chloride 8.0% w/w Phenoxy ethanol 1.0% w/w EDTA 4 Na
0.5% w/w Water QS 100%
[0051] Biostatic properties of a dry film made from a composition
according to example 4 wiped onto an inanimate surface were tested
according to ASTM E2180-01 immediately after drying (t=0); after 7
days; and after 30 days with the following results:
TABLE-US-00005 Time (t) Result 0 Total kill 7 days Total kill 30
days Total kill
[0052] Compositions according to the invention may be coated on and
are effective on a wide range of surfaces including without
limitation paper, textiles, plastics, metals, glass, and ceramics.
These materials may be coated onto articles, (for example paper
cups or food containers, or onto other surfaces.
[0053] Those skilled in the art will be able to select combinations
of polyvinyl alcohols and quaternary ammonium compounds for use in
the invention based on the teaching hereof and to select
appropriate ratios according to intended end product use. The
invention extends to include the combination, solutions of the
combination in appropriate solvents, and films formed from the
combination with or without solvents.
* * * * *