U.S. patent application number 13/733829 was filed with the patent office on 2013-05-16 for hydrogel.
This patent application is currently assigned to Euro-Celtique S.A.. The applicant listed for this patent is Euro-Celtique S.A.. Invention is credited to Wolfgang FLEISCHER, Christian LEUNER, Sabine SCHERER, Christian WAGNER.
Application Number | 20130122084 13/733829 |
Document ID | / |
Family ID | 37085744 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130122084 |
Kind Code |
A1 |
SCHERER; Sabine ; et
al. |
May 16, 2013 |
HYDROGEL
Abstract
The invention is related to gel preparations capable of
absorbing as well as releasing liquid, and the use of such gel
preparations in the treatment of wounds.
Inventors: |
SCHERER; Sabine;
(Limburg-Dietkirchen, DE) ; WAGNER; Christian;
(Gemuenden, DE) ; LEUNER; Christian; (Frankfurt,
DE) ; FLEISCHER; Wolfgang; (Ingelheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Euro-Celtique S.A.; |
Luxembourg |
|
LU |
|
|
Assignee: |
Euro-Celtique S.A.
Luxembourg
LU
|
Family ID: |
37085744 |
Appl. No.: |
13/733829 |
Filed: |
January 3, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12278036 |
Sep 23, 2008 |
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PCT/EP07/00824 |
Jan 31, 2007 |
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13733829 |
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Current U.S.
Class: |
424/450 ;
424/78.25; 514/772.6 |
Current CPC
Class: |
A61P 31/04 20180101;
A61P 17/02 20180101; A61L 15/24 20130101; A61L 26/0014 20130101;
A61L 26/008 20130101; A61P 43/00 20180101; A61L 15/44 20130101;
A61L 26/0014 20130101; A61P 31/00 20180101; C08L 33/02
20130101 |
Class at
Publication: |
424/450 ;
514/772.6; 424/78.25 |
International
Class: |
A61L 15/24 20060101
A61L015/24 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2006 |
EP |
06002149.0 |
Claims
1-46. (canceled)
47. A preparation for wound healing comprising a hydrogel
comprising 1-3% by weight of a polymer complying with the USP
Carbomer 940 series and water, said hydrogel having a pH value in
the range of 4 to 6.5, wherein the capability of the preparation to
release liquid is greater than its capability to absorb liquid when
applied to a wound, as measured under conditions in accordance with
EN 13726-1:2002. ; the preparation does not contain liposomes and
iodine; and the preparation comprises a polymer complying with the
USP Carbomer 940 series, wherein the hydrogel has a pH value in the
range of 4 to 6.5.
48. The preparation according to claim 47, wherein the preparation
further comprises one or more additives selected from the group
consisting of adjuvants, conserving agents, antioxidants,
consistency forming additives and pH-adjusting agents.
49. The preparation according to claim 47, wherein the preparation
absorbs liquid absorption of the hydrogel is less than 8% liquid,
as tested in accordance with EN 13726-1:2002.
50. The preparation according to claim 47, wherein the preparation
absorbs liquid absorption of the hydrogel is less than 15% liquid,
as tested in accordance with EN 13726-1:2002.
51. A wound dressing comprising a preparation according to claim
47.
52. A method for treating a wound, wherein said method comprises
administering, to the wound, a hydrogel preparation for wound
healing according to claim 47 comprising a polymer complying with
the USP Carbomer 940 series; wherein the hydrogel has a pH value in
the range of 4 to 6.5; the capability of the hydrogel to release
liquid is greater than its capability to absorb liquid; and the
hydrogel preparation does not include a liposome.
53. The preparation according to claim 47, further comprising at
least one antiseptic agent.
54. The preparation according to claim 53, wherein the antiseptic
agent comprises at least one compound selected from the group
consisting of oxygen- and halogen-releasing compounds and metal
compounds.
55. The preparation according to claim 54, wherein the antiseptic
agent is an iodine complex.
56. The preparation according to claim 55, wherein the iodine
complex is PVP-iodine.
57. The preparation according to claim 56, further comprising
liposomes.
58. The preparation according to claim 57, wherein the liposomes
are phospholipid-based liposomes.
59. The preparation according to claim 47, further comprising a
wound-healing promoting agent.
60. The preparation according to claim 47, wherein said preparation
is free of liposomes.
61. The preparation according to claim 47, wherein the polymer is
Carbopol 980NF.
62. The preparation according to claim 47, wherein the pH is in the
range of 5 to 6.
63. A wound dressing comprising a hydrogel comprising 1-3% by
weight of a polymer complying with the USP Carbomer 940 series and
water, said hydrogel having a pH value in the range of 4 to
6.5.
64. The wound dressing of claim 63, wherein the polymer is Carbopol
980NF.
65. The wound dressing according to claim 63, further comprising a
film forming substance.
66. The wound dressing according to claim 63, further comprising at
least one antiseptic agent.
67. The wound dressing according to claim 66, wherein the
antiseptic agent comprises at least one compound selected from the
group consisting of oxygen- and halogen-releasing compounds and
metal compounds.
Description
[0001] The present invention is related to gel preparations capable
of absorbing as well as releasing liquid, and the use of such gel
preparations in the treatment of wounds.
[0002] The damage of body tissue can have a variety of causes.
Wounds can be caused e.g. by (mechanical) contact of weapons,
tools, vehicles or other objects with the human or animal body.
Furthermore, serious damage of the skin can also be caused by
exposure to heat, cold or radiation as well as by contact with
aggressive chemicals. Body tissue can of course be damaged or even
destroyed by infective diseases, caused e.g. by microorganisms or
viruses.
[0003] Once damage of body tissue has occurred, the body will
generate new body tissue, as a main activity of the tissue repair
process. However, the generation of new body tissue may sometimes
have a negative effect, e.g. if the repaired or re-grown tissue
does not provide the same performance characteristics than the
original tissue.
[0004] Sometimes the negative effect can be solely cosmetic, in
that the re-grown tissue or repaired tissue is functional, but
perceived as disfiguring or unaesthetic. However, in more severe
cases, the necessary functionality of the tissue may be
impaired.
[0005] Thus, tissue repair can result in scar formation, which may
lead to cosmetic problems, but may also render the affected body
tissue less functional, e.g. less elastic. This effect is not
limited to the external skin of the human or animal body; scar
tissue can also lead to reduced functionality of mucosa or other
body tissue, including that of internal organs of the body.
[0006] Corresponding types of undesired tissue repair effects
include hyperkeratosis and unregulated proliferation of tissue.
[0007] The need for control of such effects in the treatment of
diseases, wounds, burns etc. has become the object of much
attention.
[0008] In the therapy of wounds, a moist wound healing environment
has been shown to be often beneficial. It has been found that the
survival of cells in a moist environment is improved, while a dry
environment promotes the die back of cells.
[0009] During wound healing, ichor is formed, which serves to
establish a liquid milieu. In addition, the ichor contains
components, like amino acids, electrolytes, etc., which support the
cell metabolism and thus enhance wound healing.
[0010] Within the first phase after tissue damage, eschar is
generally formed to "seal" the wound.
[0011] Even though eschar protects the wound from exterior
influences, it absorbs ichor and thus can cause drying of the
wound, and consequently may negatively influence the conditions for
wound healing.
[0012] In a moist wound healing environment, the formation of
eschar is reduced or even prevented. This may create the need for
alternative measures, to cover and protect the healing wound.
[0013] A further benefit of a moist wound healing environment is
that it also provides a better physiological basis for new cell
growth. Cell growth, which is required for wound healing, is
activated and the formation of new tissue is favored in the moist
wound healing environment. Some ichor formation is beneficial in
this context.
[0014] However, in case the wound environment contains too much
ichor, this may adversely affect the wound healing properties.
[0015] The moist wound healing environment required for wound
healing is improved in particular when the liquid content within
the wound is optimized by suitable substances or preparations.
[0016] A typical known method to produce a moist wound healing
environment is to use a topical gel, in particular a hydrogel, in a
wound dressing. These gel wound dressings are especially useful as
occlusive wound dressings. In the context of the present
specification the term "gel" always includes a hydrogel.
[0017] The known gels/hydrogels can be able to release liquid from
the gel matrix, thus forming a suitable liquid reservoir for the
wound environment. On the other hand, gels are in general also
capable of absorbing liquid, e.g. ichor, from the wound, if their
liquid content can be further increased and may also by this fact
provide for an improved wound healing environment.
[0018] "Liquid" generally means aqueous liquids, including liquids
provided by the gel manufacturer or user (e.g. aqua dest.,
solutions of actives, suspensions and dispersions) and also
including liquids produced by or in a wound (e.g. produced by the
affected tissue). "Liquid" includes liquid released by the gel and
liquid (which may be different from such released liquid)
re-absorbed from the wound.
[0019] Without being bound by any specific theory, it is believed
that hydrogels have an additional beneficial effect on the moist
wound healing environment by "binding" certain compounds or
contaminations into the gel, and thus improving the conditions for
healing by removal of such materials from the wound.
[0020] Another benefit of the application of gels, especially
hydrogels is, that a gel layer may "seal" the wound (without drying
it) and thus enables easier dressing changes. If e.g. the dressing
sticks to the wound, the wound may be newly injured when the
dressing is removed. If a suitable gel is covering the wound, it is
possible to change the dressing without reopening the already
recovered wound, or causing new injuries.
[0021] In the prior art, several types of gel-based wound healing
preparations have been described. Within these preparations,
various different types of gel-forming polymers have been used.
These gel-forming polymers include e.g. carboxymethylcelluloses,
modified starch and alginate polymers.
[0022] These prior art gels are especially discussed, in the art
with respect to their capacity for absorbing liquids from the
wound.
[0023] Examples of gels, which are commercially available and can
be applied in wound-healing include IntraSite.RTM. Gel (available
from Smith & Nephew), Askina.RTM. Gel (available from Braun)
and Varihesive.RTM. Gel (available from ConvaTec). These gels
exhibit good liquid absorption capabilities. Their liquid release
capabilities are, however, significantly lower than their liquid
absorption capacities.
[0024] The known gels can contain various additional ingredients to
adapt them for their intended use. For example some of these gels
comprise active agents to provide anti-inflammatory properties or
the like.
[0025] The use of wound healing promoting agents in combination
with antiseptic agent using liposomal preparations for external
applications is e.g. disclosed in EP 0 639 373. Liposomes are
highly suitable carriers for antiseptic agents, especially povidone
iodine and provide an extended topical activity by interaction with
cell surfaces.
[0026] Liposomes are well known drug or compound carriers and thus
the application of medicaments in liposomal form has been the
subject of investigation for quite some time. An overview
concerning the administration of compounds in liposomal form to the
skin is e.g. provided by the review "Targeted delivery to the
pilosebaceous unit via liposomes", Lauer et al. (1996), Advanced
Drug Delivery Reviews, 18, 311-324. This review describes the
physico-chemical characterization of liposomal preparations and
their therapeutic application for the treatment of the
pilosebaceous unit. Compounds that have been investigated for
delivery by liposomes include e.g. anti-cancer agents, peptides,
enzymes, anti-asthmatic and anti-allergic compounds and also
antibiotics.
[0027] Lately, it has been found that liposomal antiseptic
preparations of povidone iodine can be used for the treatment of
diseases of the upper and lower respiratory tract, as disclosed in
WO 99/60998 and WO99/60999.
[0028] Liposomal antiseptic preparations can be used for the
treatment of herpes, acne and other specific diseases of the skin,
as described in WO04/073720, WO04/073682 and WO04/073683.
[0029] In addition, WO 00/72822 discloses the use of liposomal
preparations comprising anti-infective and/or anti-inflammatory
agents for functional and cosmetic tissue remodeling and repair
treatments.
[0030] The prior art still leaves a desire for optimization of the
liquid content within the wound, in particular in balancing the
liquid absorption and the liquid release properties of the
gel-preparations.
[0031] Therefore, it is an object of the present invention to
provide a preparation with improved wound-healing properties.
[0032] It is a further object of the invention to provide
preparations which exhibit improved liquid release to the
wound.
[0033] It is another object of the present invention to provide a
preparation wherein the capability of the hydrogel to release
liquid is greater than its capability to absorb liquid from the
wound.
[0034] It is a further object of the invention to use the
preparation for the production of a medicament with improved wound
healing properties, in particular liquid releasing properties.
[0035] According to the invention these objects are attained by the
feature combinations of the independent claims.
[0036] Advantageous embodiments of the invention are defined in the
dependent claims.
[0037] It has been found that the preparations according to the
invention exhibit a surprisingly high capability to maintain a
moisture level within the wound, which seems to be suitable to
enhance wound healing. In particular, the inventive preparations
are able to release moisture or liquid from the gel to maintain a
suitable moisture level within the wound, and in this capacity, the
inventive preparations are superior to comparable known
preparations.
[0038] In preferred embodiments the preparation according to the
invention reveals a liquid release capability which is greater than
its liquid absorption capability. However, the liquid absorption
capability of the inventive preparation is still suitable to absorb
liquid from the wound, as necessary.
[0039] One aspect of the present invention provides gel
preparations which can comprise active agents, in particular
anti-inflammatory agents, particulate carriers, in particular
liposomes, film-forming substances or combinations thereof.
[0040] In a second aspect the present invention provides gel
preparations which do not contain either active agents, particulate
carriers, film-forming substances or combinations thereof.
[0041] In preferred embodiments, the preparations according to the
invention comprise at least one gel-forming polymer.
[0042] The gel-forming substance of the present invention can e.g.
be selected from the group consisting of agar, alginates, alginic
acids, Arabic gum, gelatine, starch, tragacanth gum,
methylcelluloses, hydroxyethylcelluloses, carboxymethylcelluloses,
polyacrylic acids and/or combinations thereof. In preferred
embodiments, acrylic acid polymers are applied. Polymers complying
the USP Carbomer 940 monograph like Carbopol 908NF or Carbomer 940)
are preferred from this group.
[0043] In specifically preferred embodiments the gel-forming
substances comprise polyacrylates, polymethacrylates, polyacrylic
acids, polymethacrylic acids, polyvinylalcohols and combinations
thereof. Polyacrylic acids are particularly preferred.
[0044] In preferred embodiments of the invention, gel-forming
substances are used in the form of hydrogels. A hydrogel, as used
in the present invention, is a gel on the basis of a hydrophilic
composition or compound, which is capable of absorbing and/or
releasing a certain amount of liquid, in particular water.
[0045] The pH of the preparation according to the invention is
preferably generally in the range from 3 to 7, more preferably from
4 to 6,5 and even more preferably in the range from 5 to 6.
[0046] The gel-forming substance is present in the preparation
according to the invention at between about 0.1% and about 10%,
preferably between about 0.5% and about 5%, more preferably between
about 1.0% and about 3.0%. All these percentages are wt.-%, based
on total preparation weight.
[0047] In a preferred embodiment the preparation according to the
invention further comprises liposomes. This often has a beneficial
effect on wound-healing.
[0048] Since, however, the addition of liposomes may cause some
loss of liquid release capability, it is preferred in other
embodiments, to provide the inventive preparation without addition
of liposomes and/or other particulate carrier materials.
[0049] The amphiphilic substances generally known in prior art to
form liposome membranes can be employed in the context of the
invention, as long as they are pharmaceutically acceptable for the
intended application. Presently, liposome-forming systems
comprising lecithin are preferred. Such systems can comprise
hydrogenated soy bean lecithin, besides cholesterol and disodium
succinate-hexahydrate or the like. Usually one will make sure that
the liposome-forming materials do not show any unintended
reactivity with any other ingredient. In case, the preparation
according to the invention comprises a reactive agent, e.g.
elemental iodine, higher contents of compounds with reactive groups
such as double-bonds, for example high cholesterol contents, are
usually avoided. It is presently specifically preferred to use
hydrogenated soy bean lecithin as the sole membrane-forming agent.
Commercially available products such as Phospholipon.RTM. 90 H are
preferred.
[0050] As can be taken from the review of Lauer A. C. et al. 1995
(vide supra) phospholipid-based liposomes may also be generally
used for production of liposomes that discharge a cargo of actives
into the skin. According to this review, the use of non-ionic
liposomes, which can be formed with phosphatidylcholin, is also an
option. Other components that may be used for the formation of
micelles are also known to the person skilled in the art and may be
used for the production of preparations according to the
invention.
[0051] The known prior art methods for forming liposome structures
can generally be used in the context of the invention. Broadly,
these methods comprise mechanical agitation of a suitable mixture
containing the membrane-forming substance and water or an aqueous
solution. Filtration through suitable membranes is preferred in
order to form a substantially uniform liposome size.
[0052] The average size of the liposomes according to this
invention can vary over a broad range, generally from about 1 .mu.m
to about 150 .mu.m. Liposomes or particulate carriers having sizes
in the range of about 1 .mu.m and 70 .mu.m are preferred. Generally
the size of liposomes should be selected such that a good
penetration into the skin is guaranteed. A particularly preferred
embodiment of the invention therefore comprises liposomes having a
size of between about 10-30 .mu.m.
[0053] Additionally these preparations preferably comprise
liposomes of rather large size such as liposomes having a size of
between about 1 .mu.m and 30 .mu.m, preferably between about 10
.mu.m and 30 .mu.m, more preferably between 20 .mu.m and 30 .mu.m
and most preferably at around 25 .mu.m. The formulation as a
hydrogel is preferred.
[0054] Generally, liposomes having a rather small average size are
better suited for production of solutions, dispersions and
suspensions. Such rather small sizes typically comprise sizes of
around 1 .mu.m to 10 .mu.m, or even smaller in the case of
solutions. In contrast, gel or ointment formulations may comprise
liposome of a size of up to 50 .mu.m.
[0055] Even though we discuss the use of liposomes in the inventive
preparation, it is assumed that further particulate carrier
materials known to a person skilled in the art can similarly be
used. These alternative materials may be e.g. microspheres,
nanoparticles, or large porous particles.
[0056] In a preferred embodiment, the preparation of the invention
further comprises at least one film-forming substance.
[0057] In some cases, the addition of the film-forming substance
may cause some loss of liquid release capability which may then
outweigh the benefits provided by the gel in terms of increased
moisture content. It is therefore preferred in some embodiments to
provide inventive preparations without the addition of a
film-forming substance.
[0058] In a specially preferred embodiment, the film forming
substance of the present invention is a hyetellose, hypromellose,
hyaluronate, polyvinylalcohol or polyvinylpyrrolidone. A particular
preferred film-forming substance is polyvinylpyrrolidone (PVP).
[0059] It is presently believed that the film forming substance can
be incorporated into the liposome or the liposome structure as well
as be present at or near the surface of the liposomes.
[0060] The film forming substance applied in the present invention
is present in the range between 0.1% to 10%, preferably between
0.5% and 7%, more preferably between 1% and 5%, most preferably
between 2% and 4%, based on the total weight of the
preparation.
[0061] In other preferred embodiments of the invention the
preparation further comprises an active agent, in particular an
anti-inflammatory agent.
[0062] Anti-inflammatory agents in accordance with the present
invention broadly include antibiotic and antiviral preparations,
and more specifically comprise antiseptic agents, antibiotic
agents, corticosteroids and the like. Antiseptic agents are
preferred.
[0063] In the context of this invention antiseptic agents are
understood to include those disinfecting agents which are
pharmaceutically acceptable and suitable for the intended
treatment.
[0064] Preferred antiseptic agents comprise oxygen- and
halogen-releasing compounds, preferably iodine and iodine
complexes, and/or metal compounds, preferably silver- and
mercury-compounds.
[0065] Further antiseptic compounds comprise organic disinfectants,
including formaldehyde-releasing compounds, phenolic compounds
including alkyl- and aryl-phenolic compounds, chinolines and
acridines, hexahydropyrimidines, quartenary ammonia compounds,
imines and salts thereof and guanidines.
[0066] It may be advantageous to include actives, such as
disinfectants and anti-septics, at lower contents than in the prior
art. Where the liquid level adjustment and control performance of
the inventive preparations are more important than anti-infective
aspects, the actives may advantageously be provided at
concentrations only up to 90%, only up to 75%, sometimes only up to
50% and in some preferred embodiments only up to 25% of the
concentrations known e.g. from comparable preparations in EP 0 639
373 (while in all these cases the concentration is non-zero and
preferably at least 5%, more often at least 10% of those known from
EP 0 639 373). This holds for inventive preparations containing
liposomes, but also for such that do not contain liposomes (or
other particulate carrier materials).
[0067] While EP 0 639 373 uses PVP-iodine as a preferred active
agent other active agents other than PVP-iodine are used in
specific preferred embodiments of the present invention.
[0068] If the preparation comprises liposomes, the active agent,
preferably antiseptic agent, is often associated with the
liposomes.
[0069] Since, however, in some cases the addition of particulate
carriers, film-forming substances, active agents or combinations
thereof may cause some loss of liquid release capability, it is
specifically preferred in other embodiments, to omit either one of
these ingredients particulate carriers, film-forming substances,
active agents or combinations thereof.
[0070] A specifically preferred embodiment provides a preparations
according to the invention which do not contain liposomes. In some
specifically preferred embodiments, the inventive preparation is
free of particulate carriers.
[0071] In a particularly preferred embodiment of the invention, the
preparation does not contain iodine as active agent. In another
preferred embodiment, the preparation is free of antiseptic agents.
In still another preferred embodiment, the preparation according to
the invention is free of anti-inflammatory agents. In still further
preferred embodiments, the inventive preparations are free of
active agents.
[0072] In another preferred embodiment, the preparation according
to the invention is free of film-forming substances.
[0073] Free of antiseptic agent, in the context of the present
invention, means that the preparation does not comprise oxygen- and
halogen-releasing compounds, preferably iodine and iodine
complexes, and/or metal compounds, preferably silver- and
mercury-compounds, organic disinfectants, including
formaldehyde-releasing compounds, phenolic compounds including
alkyl- and aryl-phenolic compounds, chinolines and acridines,
hexahydropyrimidines, quartenary ammonia compounds, imines and
salts thereof and guanidines.
[0074] Free of anti-inflammatory agents means that the inventive
preparation does not contain antibiotic and antiviral preparations,
antibiotic agents or corticosteroids.
[0075] Free of active pharmaceutically agents in the context of
this invention means that the inventive preparation does not
contain any pharmaceutically active agents. The hydrogel itself is
not covered by the term pharmaceutically active agent.
[0076] Free of particulate carrier means that the inventive
preparation does not contain particulate carriers, especially not
liposomes, microspheres, nanoparticles, or large porous
particles
[0077] Free of film-forming substances means that the inventive
preparation does not contain film-forming substances, especially
not hyetellose, hypromellose, hyaluronate, polyvinylalcohol or
polyvinylpyrrolidone.
[0078] The preparation according to the invention may comprise
further additives and adjuvants such as conserving agents,
antioxidants, consistency fanning additives or pH-adjusting
agents.
[0079] The preparations according to the invention can optionally
comprise wound healing agents. Suitable wound healing agents
comprise e.g. dexpanthenol, allantoines, azulenes, tannins,
vitamins (preferably vitamin B), and derivatives thereof.
[0080] The preparations according to the invention are capable of
maintaining a level of moisture/liquid within the wound to an
extent that wound healing is enhanced.
[0081] The level of moisture which an inventive preparation is
capable to maintain in a wound can generally be measured by the
capability to absorb a certain amount of liquid or to the ability
to release liquid to a substrate and/or wound. The liquid release
properties of the preparations according to the invention are of
particular interest in the context of the present invention.
[0082] To determine the so-called "liquid affinity" of hydrogels,
standard procedures are known to a person skilled in the art. A
preferred test follows European norm EN 13726-1:2002. By this, the
capability of hydrogels, in particular amorphous hydrogels, to
release a liquid to gelatine or to absorb liquid from agar are
measured. If necessary, the conditions of the test are adapted for
the intended use.
[0083] The liquid affinity of hydrogel dressings is specified as
the percentage of the capability to absorb or release liquids
determined by the increase or decrease, respectively in gel
weight.
[0084] The preparations according to the invention have been proven
to be particularly suitable to release liquid or moisture, to
wounds as well as test substrates. In preferred embodiments the
preparation releases at least 8%, preferably at least 10%, more
preferably at least 12%, at least 14%, at least 16%, at least 18%,
at least 20% or most preferably at least 25% of the liquid from the
test substrate under the test conditions of EN 13726-1:2002.
[0085] In preferred embodiments the liquid absorption, measured in
gain of gel weight, is less than 15%, preferably less than 12%,
more preferably less than 10%, less than 8% , less than 6%, less
than 5% and most preferably less than 4% .
[0086] It is apparent that the preparations according to the
invention may be designed to provide varying liquid absorption and
release properties, and that for this purpose, all combinations of
values given in above ranges may be selected.
[0087] The liquid affinity of hydrogel dressings can be classified
according to the percentage of the absorption or release of
liquid.
[0088] A wound dressing which absorbs 0 to 10% of its weight from
Agar is classified as "type 1", greater than 10 to 20% as "type 2",
greater than 20 to 30% as "type 3", greater than 30 to 40% as "type
4" and greater than 40 to 50% as "type 5", respectively.
[0089] The liquid affinity with respect to the liquid release to
gelatine, which is measured by the decrease of the gel weight, is
classified as follows: a liquid release in the range of 0 to 5% as
"type a", greater than 5% to 10% as "type b", greater than 10% to
15% as "type c", greater than 15% to 20% as "type d", greater than
20% to 25% as "type e".
[0090] Correspondingly, a wound dressing that absorbs about 25%
liquid, based on the original weight of the gel, from agar and
hardly releases any liquid (less than 5%) to gelatine is classified
as a "3a type" wound dressing.
[0091] In particularly preferred embodiments of the invention the
preparation is classified as "type 1c", "type 1d", "type 1e" or
"type 2e".
[0092] In a preferred embodiment the preparation according to the
invention can applied in pre-gel form at the desired locus, e.g. as
a liquid. The liquid preparation can easily be applied e.g. in form
of a spray.
[0093] Such a liquid preparation can comprise water and/or any
pharmaceutically acceptable solvent or any mixture of
pharmaceutically acceptable solvents and water (water, as used
anywhere in this specification includes all kinds of aqueous
systems, like buffer solutions and the like). Preferably the
pharmaceutically acceptable solvent(s) comprises one or more
organic solvent(s). Volatile alcohol(s) are particularly preferred.
Such alcohols are e.g. ethanol, n-propanol, i-proponal, and/or
butanols and combinations of the afore-mentioned. After the
preparation is applied at the intended locus, the hydrogel is
formed by evaporation of one or more volatile solvent(s) or by
absorption of the liquid component by body tissue.
[0094] Upon application of the pre-gel forming preparation at least
one of the volatile components evaporates or is absorbed and forms
gel preparations according to the invention.
[0095] Suitable pre-gels are e.g. disclosed in EP 0 704 206 which
is herein incorporated by reference.
[0096] In general, the inventive preparations can be prepared by
dispersing the gel-forming polymer in an amount of a suitable
liquid or solvent, preferably water. The preparations according to
the invention comprise between about 0.1 g and about 10 g,
preferably between about 0.5 g and about 5 g, more preferably
between about 1.0 g and about 3.0 g gel-forming polymer per 100 g
preparation. The pH of the mixture can be adjusted by addition of a
suitable acid or base, which are preferably added in solution, if
necessary. The pH of the final preparation is between about 3 and
about 7, preferably between about 4 and about 6.5, more preferably
between about 5 and about 6. If the desired conditions (pH-value,
etc.) are met, the gel is allowed to swell for an appropriate
period of time.
[0097] In those preferred embodiments, wherein the preparation
further comprises liposomes, the inventive preparations can be
prepared by combining a suitable gel with liposomes or a liposomal
preparation. The liposomal preparation can be prepared by any
method known to a person skilled in the art. Suitable methods are
e.g. disclosed in EP 0 639 373. If desired, elevated temperatures
can be applied to facilitate the formation of the liposomal
preparation. In preferred embodiments of the invention, the
liposomal preparation is in the range of 0.1% to 30%, preferably in
the range of 1% to 20%, even more preferably between 2% and 20%,
based on the total weight of the preparation.
[0098] The liposomal preparation and the gel can be combined and
homogenized, if necessary, to form a preparation according to the
invention.
[0099] The person skilled in the art is well aware that further
additives and adjuvants like conserving agents can be added to the
inventive preparations at a time suitable to achieve preparations
for the intended use. The skilled person also knows how to further
process the inventive preparations in the production of
pharmaceutical preparations, as necessary.
[0100] In case the specifically preferred embodiment further
comprises at least one film-forming substance, the film-forming
substance can be present in the range between 0.1 g to 10 g,
preferably between 0.5 g and 7 g, more preferably between 1 g and 5
g, most preferably between 2 g and 4 g, based on 100 g of the
preparation.
[0101] The film-forming substance is generally provided in
solution, but can also be provided in any other suitable form known
to the person skilled in the art. In a specifically preferred
embodiment, the film-forming substance is at first combined with
the liposomal preparation and subsequently added to the formed gel.
The resulting mixture can then be further processed, as
necessary.
[0102] In some preferred embodiments, an active agent, in
particular an anti-inflammatory agent is comprised by the inventive
preparation. In some specific embodiments, it is advantageous to
provide the active agent at concentrations which are lower than in
the prior art. The concentration of the active agent is, however,
adjusted for the intended use of the inventive preparations. Some
specifically preferred embodiments of the present invention
comprise other active agents than PVP-iodine.
[0103] The active agent may be in a suitable form for combination
with the liposomal preparation. In general, the combined mixture is
subsequently added to the formed gel and can further be processed
to form a preparation according to the invention.
[0104] In case the inventive preparation comprises further
ingredients or adjuvants like conservatives, buffer solutions,
etc., the skilled person is able to select and incorporate these
substances into the preparations according to the invention for the
intended use.
[0105] Specific inventive formulations are notable from the
embodiment examples.
EMBODIMENT EXAMPLES
[0106] The features and advantages of this invention will become
clear in more detail from the ensuing description of preferred
embodiments. In the embodiments, which include an active agent,
povidone iodine is exemplified and liposomes are chosen as the
carrier. However, the povione iodine can be omitted to provide
embodiments of the present invention which do not comprise an
active agent, in particular any antiseptic agent. It is apparent
for a person skilled in the art that PVP-iodine can be substituted
by another active agent, suitable for the intended use. Likewise,
the exemplified embodiments serve to illustrate mutatis mutandis,
the characteristics of inventive preparations which comprise
neither actives nor particulate carrier materials.
[0107] According to the invention, particulate carriers such as
"large porous particles" or other micelles, nanoparticles, etc.
instead of the exemplified liposomes, can be formulated with active
agents like PVP-iodine.
Embodiment Example I
[0108] A Carbopol 980 NF composition was prepared. The amounts
shown in Table I were used either for analytical or scale up
compositions.
TABLE-US-00001 TABLE I Pos. Substance Amount (g/100 g) Scale up
(kg/1000 kg) A H.sub.2O 90.00 900.00 A Carbopol .RTM. 980 NF 1.50
15.00 B H.sub.2O 4.60 46.00 B NaOH solid 0.46 4.6 C H.sub.2O ad 100
ad 1000
[0109] Pos. stands for Position (see also below Table II). Carbopol
980 NF was purchased from BF Goodrich or Noveon.
[0110] In Table II, column 2 the exact order of steps and the
parameters of each step are given. All steps were performed at room
temperature except where indicated otherwise. All substances were
of a purity grade common for pharmaceutical preparations.
TABLE-US-00002 TABLE II No. 1 Carefully add Carbopol of Pos. A to
water of Pos. A, which is provided in a beaker Disperse by stirring
(approx. 305 upm) for about 30 min Stir until no inhomogeneities
are visible Determine pH 2 Provide water of Pos. B in a separate
beaker and dissolve NaOH of Pos. B by stirring 3 Adjust pH of
product of step 1 with NaOH solution to 5.5 Stir for 3 min after
each addition of NaOH at about 350 upm Stir for at least 10 min at
about 350 upm Allow gel to swell
Embodiment Example II
Formulation with buffer and German II
[0111] A Carbopol 980NF composition was prepared. The amounts shown
in Table III were used either for analytical or scale up
compositions.
TABLE-US-00003 TABLE III Pos. Substance Amount (g/100 g) Scale up
(kg/5000 kg) A H.sub.2O 40.00 2000 A Germall II 0.30 15.00 B
Carbopol 980 NF 1.50 75.0 C H.sub.2O 4.60 230.00 C NaOH solid 0.46
23.00 D H.sub.2O 48.00 2400 E H.sub.2O 3.00 150 E
Na.sub.2(HPO.sub.4) 0.225 11.25 E Citric acid 0.1065 5.33 F
H.sub.2O ad 100 ad 5000
[0112] Pos. stands for Position (see also below Table IV). Carbopol
980NF was purchased from BF Goodrich.
[0113] In Table IV, column 2 the exact order of steps and the
parameters of each step are given. All steps were performed at room
temperature except where indicated otherwise. All substances were
of a purity grade common for pharmaceutical preparations.
TABLE-US-00004 TABLE IV No. 1 Germall II of Pos. A is carefully
added to water of Pos. A into an Unimax LM5 Dissolve Germall II by
stirring at 100 upm (units per minute) 2 Carefully add Carbopol 980
NF of Pos. B Disperse by stirring (approx. 100 upm) for about 30
min Break up agglomerates, if necessary Subsequent homogenization
is performed until no inhomogeneities are visible Let gel swell for
at least 16 hours 3 Provide water of Pos. C in a beaker and
dissolve NaOH of Pos. C by stirring 4 Adjust pH of gel of step 2
with NaOH solution to 3 (+/-0.2) Addition can be performed into an
open Unimix mixer Stir for 10 min after each addition 5 Water of
Pos. D is pumped via cap valve into Unimax LM5 and stirred for 10
min (100 upm) Subsequent homogenization is performed for 2 min at
8500 upm 6 Adjust pH of gel by addition of NaOH solution to 5.5
(+/-0.2) Addition can be performed into an open Unimix LM 5 Rinse
circulation pump lines by homogenization and subsequent stirring
for 10 min Adjust pH, if necessary 7 Warm water of Pos. E to
40.degree. C. and dissolve salts of Pos. E (Na.sub.2(HPO.sub.4) and
citric acid) while stirring Let cool to .ltoreq.30.degree. C. while
stirring 8 Add buffer solution to gel and stir for 10 min 9
Determine and add residual amount of water (calculate 5000 sum of
all ingredients) Stir for 10 min Rinse circulation pump lines by
homogenization
Embodiment Example III
+Germall II
[0114] A liposomal Carbopol 980NF composition was prepared. The
amounts shown in Table V were used either for analytical or scale
up compositions.
TABLE-US-00005 TABLE V Pos. Substance Amount (g/100 g) Scale up
(kg/5000 kg) A H.sub.2O 40.00 2000 A Germall II 0.30 15.00 B
Carbopol 980NF 1.50 75.0 C H.sub.2O 4.60 230.0 C NaOH solid 0.46
23.00 D H.sub.2O 15.00 750 D Phospholipon 90 H 3.00 150 E H.sub.2O
27.50 1375 F H.sub.2O 2.50 125 G H.sub.2O 3.00 150 G
Na.sub.2(HPO.sub.4) 0.225 11.25 G Citric acid 0.1065 5.33 H
H.sub.2O Ad 100 ad 5000
[0115] Pos. stands for Position (see also below Table V). Carbopol
980NF was purchased from BF Goodrich. Phospholipon 90 H was
purchased from Rhone Poulene.
[0116] In Table VI, column 2 the exact order of steps and the
parameters of each step are given. All steps were performed at room
temperature except where indicated otherwise. All substances were
of a purity grade common for pharmaceutical preparations.
TABLE-US-00006 TABLE VI No. 1 Germall II of Pos. A is carefully
added to water of Pos. A into an Unimax LM 5 Dissolve Germall II by
stirring at 100 upm (units per minute) 2 Carefully add Carbopol
980NF of Pos. B Disperse by stirring (approx. 100 upm) for about 30
min Break up agglomerates, if necessary Subsequent homogenization
is performed until no inhomogeneities are visible Let gel swell for
at least 16 hours 3 Provide water of Pos. C in a beaker and
dissolve solid NaOH of Pos. C by stirring while heating to
65.degree. C. Add Phospholipon of Pos. D carefully and stir for 60
min (450 upm) at 65.degree. C. 4 Cool dispersion of step 3 while
stirring (100 upm) to 30.degree. C. (water bath) and compensate
water loss, if necessary 5 Provide water of Pos. C in a beaker and
dissolve NaOH of Pos. C by stirring 6 Adjust pH of gel of step 2 by
addition of NaOH solution to 3.0 (+/-0.2) Addition can be performed
into an open Unimix LM 5 Stir for 10 min after each addition 7 Add
water of Pos. E to liposomal dispersion of step 4 while stirring
and stir for additional 10 min 8 Liposomal dispersion is pumped via
cap valve into Unimix LM5 and stirred for 10 min at 100 upm Rinse
beaker with water of Pos. F and add to preparation Subsequent
homogenization is performed for 2 min at 8500 upm 9 Adjust pH of
gel by addition of NaOH solution to 5.5 (+/-0.2) Addition can be
performed into an open Unimix LM 5 Stir for 10 min after each
addition Rinse circulation pump lines by homogenization and stir
for at least 10 min Adjust pH, if necessary 10 Warm water of Pos. E
to 40.degree. C. and dissolve salts of Pos. E (Na.sub.2(HPO.sub.4)
and citric acid) by stirring Let cool to .ltoreq.30.degree. C.
while stirring 11 Add buffer solution to gel and stir for 10 min 12
Determine and add residual amount of water (calculate 5000 sum of
all ingredients), stir for 10 min, Rinse circulation pump lines by
homogenization
Embodiment Example IV
[0117] A liposomal Carbopol 980NF composition was prepared. The
amounts shown in Table VII were used either for analytical or scale
up compositions.
TABLE-US-00007 TABLE VII Pos. Substance Amount (g/100 g) Scale up
(kg/5000 kg) A H.sub.2O 40.00 2000 A Germall II 0.30 15.00 B
Carbopol 980NF 1.50 75.0 C H.sub.2O 4.60 230.0 C NaOH solid 0.46
23.0 D H.sub.2O 15.00 750 D Phospholipon 90 H 3.00 150 E H.sub.2O
22.00 1100 E PVP (Kollidon 30) 3.00 150 F H.sub.2O 2.50 125 G
H.sub.2O 2.50 125 H H.sub.2O 3.00 150 H Na.sub.2(HPO.sub.4) 0.225
11.25 G Citric acid 0.1065 5.33 I H.sub.2O Ad 100 ad 5000
[0118] Pos. stands for Position (see also below Table VIII).
Carbopol 980NF was purchased from BF Goodrich, Phospholipon 90 H
was purchased from Rhone Poulene and PVP (Kollidon 30) from
BASF.
[0119] In Table VIII, column 2 the exact order of steps and the
parameters of each step are given. All steps were performed at room
temperature except where indicated otherwise. All substances were
of a purity grade common for pharmaceutical preparations.
TABLE-US-00008 TABLE VIII No. 1 Germall II of Pos. A is carefully
added to water of Pos. A in an Unimix LM 5 Dissolve Germall II by
stirring at approx. 100 upm (units per minute) 2 Carefully add
Carbopol 980NF of Pos. B Disperse by stirring (approx. 100 upm) for
about 30 min Break up agglomerates, if necessary Subsequent
homogenization is performed until no inhomogeneities are visible
Let gel swell for at least 16 hours 3 Provide water of Pos. D in a
beaker and dissolve solid NaOH of Pos. C by stirring while heating
to 65.degree. C. Add Phospholipon of Pos. D and stir at 65.degree.
C. for 60 min (450 upm) 4 Cool dispersion of step 3 while stirring
(100 upm) to 30.degree. C. (water bath) and compensate water loss,
if necessary 5 Provide water of Pos. C in a beaker and dissolve
NaOH of Pos. C by stirring 6 Adjust pH of gel of step 2 by addition
of NaOH solution to 3.0 (+/-0.2) Addition can be performed into an
open Unimix LM5 Stir for 10 min after each addition 7 Water of Pos.
E is provided in a beaker and PVP of Pos. E is carefully added
while stirring. Stir for 30 min at 450 upm 8 Add PVP of step 7 to
liposomal dispersion of step 4 and stir for 10 min. Rinse beaker
with water of Pos. F and add to preparation 9 Liposomal dispersion
is pumped via cap valve into Unimix LM5 and stirred for 10 min at
100 upm Rinse beaker with water of Pos. G and add to preparation
Subsequent homogenization is performed for 2 min at 8500 upm 10
Adjust pH of gel by addition of NaOH solution to 5.5 (+/-0.2)
Addition can be performed into an open Unimix LM5 Stir for 10 min
after each addition Rinse circulation pump lines by homogenization
and stir for at least 10 min Adjust pH, if necessary 11 Warm water
of Pos. H to 40.degree. C. and dissolve salts of Pos. H
(Na.sub.2(HPO.sub.4) and citric acid) by stirring Let cool to
.ltoreq.30.degree. C. while stirring 12 Add buffer solution to gel
and stir for 10 min 13 Determine and add residual amount (calculate
5000 sum of all ingredients), stir for at least 10 min,
Embodiment Example V
[0120] A liposomal composition containing PVP-iodine as an active
agent was prepared. The amounts shown in Table IX were used either
for analytical or scale up compositions.
TABLE-US-00009 TABLE IX Pos. Substance Amount (g/100 g) Scale up
(kg/1500 kg) A H.sub.2O 15.0 200.0 A Phospolipon 90 H 3.0 45.0 B
H.sub.2O 40.0 600.0 B Carbopol .RTM. 980 NF 1.5 22.5 C H.sub.2O 2.0
30.0 C KIO.sub.3 0.0708 1.09 D H.sub.2O 20.0 300.0 D PVP-iodine
30/06 3.0 45.0 Available iodine (10%) E H.sub.2O 2.5 50.0 F
H.sub.2O 2.5 50.0 G H.sub.2O 4.6 69.0 G NaOH solid 0.46 6.9 I
Citric acid, H.sub.2O free 0.1065 1.059 I Na.sub.2(HPO).sub.4,
H.sub.2O free 0.225 3.37 I H.sub.2O 3.0 45.0 H H.sub.2O Ad 100.0 ad
1500
[0121] Pos. stands for Position (see also below Table X).
Phospholipon.RTM. 90 H was purchased from Aventis (Germany).
Carbopol.RTM. 980 NF was purchased from Noveon Inc. (USA) or
Gattefosse (Germany) and PVP Iodine 30/06 was purchased from BASF
(Germany).
[0122] In Table X, column 2 the exact order of steps and the
parameters of each step are given. Column 3 discusses non-exclusive
alternatives. All steps were performed at room temperature except
where indicated otherwise. All substances were of a purity grade
common for pharmaceutical preparations.
TABLE-US-00010 TABLE X No. Embodiment example VII Alternatives 1
Carbopol 980 NF is mixed into H.sub.2O Substances: Other
gel-forming without agglomeration (Pos. B). substances may be used.
Stirring for 30 min at approx. 30 upm Homogenization time can vary:
(units per minute) in conventional shorten to 1 min stirrer. Visual
control for Polyacrylic prolong to 10 min acid-agglomerates.
(caution! gel structure may be If necessary, homogenize gel in
destroyed) conventional homogenisator for 2 min Stirring time can
be altered as desired. at 3000 upm. Only condition is that gel is
free of Subsequently stir gel for 30 min at 30 agglomerates at the
end. upm in conventional stirrer. Swelling time may be altered from
15 min Eventually control again for to 5 days. Preferably the gel
has Polayacrylicacid-agglomerates. formed before other substances
are If present, remove them and stir again added. for 15 min at 30
upm. Eventually Adjustment of pH to 2-8 may be homogenize again.
performed at this stage. Adjustment to Let gel swell for at least
14 h. pH 3-6 is preferred. 2 Dissolve H.sub.2O and KIO.sub.3
completely in H.sub.2O-temperature may be adjusted to a suitable
vessel (Pos. C). anywhere between ambient temperature Alternatively
a 30-40% KIO.sub.3 solution and 100.degree. C. may be used.
KIO.sub.3 is not obligatory. 3 Dissolve NaOH completely in H.sub.2O
NaOH is used in concentrations (Pos. G). common for pharmaceutical
preparations. Other Bases or substances suggested by the supplier
of the gel forming substances may also be used for formation of gel
structure as e.g. KOH, Triethanol-amine, 2-Amino-2-methyl-
1-propanol, tris(hydroacnemethyl)aminoethan, 2-
hydroacnepropyl-ethylen-diamine, diisopropanolamine. 4 Mix
PVP-iodine into H.sub.2O while Stirring time and speed can be
altered stirring at 1000 upm in conventional arbitrarily. stirrer
(Pos. D). Important: PVP-Iodine has to be Stir mixture for futher
60-70 min at dissolved completely. 1000 upm until it is completely
dissolved. 5 Warm H.sub.2O to 65.degree. C. while stirring Possible
temperature range: 40.degree. C.-120.degree. C. with 1000 upm in
conventional stirrer. 50.degree. C.-75.degree. C. is preferred Then
add slowly Phospholipon .RTM. 90 H because of phase transition
temperature. (Pos. A). Take care that no Other liposome-forming
materials or agglomerates are formed. mixtures thereof may be used.
Stir dispersion for further 90 min at Stirring time and speed: Is
dependent 65.degree. C.-70.degree. C. and 1000 upm. on equipment. A
complete dispersion Subsequently cool liposomal has to be achieved.
Apparatus of the dispersion to .ltoreq.30.degree. C. while stirring
at rotor/stator principle, high pressure 500 upm homogenisators,
ultrasound or extrusion technology may also be used for stirring. 6
By adding the NaOH-solution (No. 3) Further processing to a gel may
be the gel is adjusted to a pH of 3.0 (.+-.0.2). feasible without
pH pre-adjustment and is dependent on the gel-forming substance 7
The KIO.sub.3 solution (No. 2) is added to Reaction between
KIO.sub.3 and PVP-iodine the PVP-Iodine solution (No. 4) while is
time dependent. To ensure a complete stirring at 1000 upm.
reaction, the stirring time has to be Stirring continued for at
least 60 min. adapted accordingly. Thus, stirring time may be
between 10 min and 2 h 8 The PVP-iodine-KIO.sub.3-solution is
Stirring time is variable depending on pumped into the liposomal
dispersion until when an homogeneous mixture (No. 5). has formed.
Subsequently it is stirred for 30 min at 1000 upm. 9 The
PVP-iodine-KIO.sub.3-liposomes- Stirring time is variable depending
on dispesion is added to the gel (No. 6). until when an homogeneous
mixture It is stirred for 30 min at 30 upm. has formed.
Subsequently homogenization is Stirring time should be as short as
performed by forced circulation possible so that gel structure gets
not pumping for 2 min at 2800 upm. disrupted. After checking for
agglomerates, it may be homogenized for further 1-2 min. 10 Remove
agglomerates if present. Adjust stirring time and speed to gel Add
50.0 kg NaOH-solution (in the quality. scale up, point 3) while
stirring at 30 Amounts of NaOH may vary. Adding upm. of base by
step wise adjustment until Stir for further 30 min at 30 upm at
desired pH is achieved. .ltoreq.30.degree. C. Cool if necessary.
Determine pH and add additional NaOH until an pH of 5.5 (.+-.0.2)
is achieved. After each adding step stir for 20 min. After each
adding step homogenize by circulation pressure pumping for 15 sec
at 1000 upm. After adjustment of pH stir for further 15 min at 30
upm. Check pH and correct if necessary. After successful pH
adjustment add remaining H.sub.2O amount which depends on the
amount of NaOH used. 11 Mix buffer solution at 30.degree. C. while
Temperature can be raised to 40.degree. C. stirring until it is
completely dissolved Other suitable buffers may also be used. (Pos.
I). 12 Buffer solution is added to the product The desired product
quality (storage (No. 10) while stirring for 15 min at stability)
is achieved by addition of the 30 upm. buffer. Degas by application
of vacuum. Stirring time is variable depending on until when an
homogeneous mixture has formed. Degasing may be achieved by other
means than vacuum. 13 Add the remaining H.sub.2O-amount (Pos.
Stirring time is variable depending on H) and stir for 30 min at 25
upm until when an homogeneous mixture Optionally homogenization may
be has formed. performed by circulation pressure pumping for 15 sec
at 1000 upm. Stir for another 30 min. Check visually for
agglomerates
[0123] Positions E and F of Table IX are used for washing the
KIO.sub.3- and the PVP-iodine vessels (points 2 and 4 of Table
X).
[0124] Determination of the Liquid Affinity
[0125] The test procedures of he European norm EN 13726-1:2002, in
particular the German version EN 13726-1:2002 (D), were followed if
not stated otherwise.
[0126] The determination of the liquid affinity of the inventive
preparations and reference products was conducted in a sealed
laboratory at temperatures of 25 (.+-.2) .degree. C. and 38%
relative humidity.
[0127] Agar and gelatine which are used as test substrates were
purchased from Merck.
[0128] The tests were performed according to test procedures for
primary wound dressings.
[0129] The following embodiments were tested: [0130] a)
Carbopol.RTM. 980 NF Gel [0131] b) Liposomal Carbopol.RTM. 980 NF
Gel [0132] c) Liposomal Carbopol.RTM. 980 NF Gel and PVP
[0133] The capability of the inventive preparations to absorb and
release liquid to the test substrate was determined as a percentage
of weight gain or weight loss of the samples. The results of the
examples a) to c) are shown in Tables XI to XIII.
[0134] For the embodiment examples a) to c) as well as the
comparative examples d) to g) measurements of the liquid absorption
and liquid release capability were conducted. Five measurements
each, numbered samples 1 to 5 within each example (embodiment and
comparative examples) were performed (for the embodiment examples
see Table XI to XIII and for comparative examples see Tables XIV to
XVI). The mean of these five measurements as well as the standard
deviation were determined and referred to within the further
discussion.
TABLE-US-00011 TABLE XI Liquid affinity of Carbopol .RTM. 980 NF
Gel (a): Agar (absorption) Gelatine (release) liquid affinity
liquid affinity Sample gain of gel weight (%) loss of gel weight
(%) 1 4 -18 2 4 -18 3 4 -18 4 4 -18 5 4 -19 Mean 4 -18 S.sub.rel 0%
2.5%
[0135] The inventive Carbopol.RTM. 980 NF gel (a) releases liquid
very well, which is demonstrated by 18% loss of gel weight. The
inventive gel exhibits a liquid absorption of 4%. The Carbopol.RTM.
980 NF gel a) is a "type 1d" gel by the standards of
EN13726-1:2002.
TABLE-US-00012 TABLE XII Liquid affinity of liposomal Carbopol
.RTM. 980 NF Gel (b): Agar (absorption) Gelatine (release) liquid
affinity liquid affinity Sample gain of gel weight (%) loss of gel
weight (%) 1 5 -17 2 5 -17 3 5 -17 4 5 -17 5 5 -18 Mean 5 -17
S.sub.rel 0% 2.6%
[0136] The liposomal Carbopol.RTM. NF980 gel (b) reveals good
liquid release properties, which are at 17% weight loss, only
slightly lower than those of Carbopol.RTM. 980 NF preparation a).
The liquid absorption capacity is slightly increased in comparison
to a) (see Table XI) and revealed 5% liquid absorption. The
liposomal gel preparation b) can be classified as a "type1d" by the
standards of EN 13726-1:2002.
TABLE-US-00013 TABLE XIII Liquid affinity of liposomal Carbopol
.RTM. 980 NF Gel and PVP (c): Agar (absorption) Gelatine (release)
liquid affinity liquid affinity Sample gain of gel weight (%) loss
of gel weight (%) 1 9 -14 2 9 -14 3 8 -14 4 9 -14 5 8 -14 Mean 9
-14 S.sub.rel 6.4% 0%
[0137] The liquid release properties of the inventive liposomal gel
(c) including PVP as a film-forming substance reveals a liquid
release value of 14% and an absorption capacity of 9%. The
liposomal Carbopol.RTM. 980 NF Gel including PVP is a "type 1c" by
the standards of EN13726-1:2002.
[0138] By comparison, four commercially available gel preparations
were tested with respect to their liquid affinity: [0139] d)
Askina.RTM. Gel (available from Braun) [0140] e) IntraSite.RTM. Gel
(available from Smith & Nephew) [0141] f) NU-Gel (available
from Johnson & Johnson) [0142] g) Varihesive.RTM. Hydrogel
(available from convaTec)
[0143] The results of the liquid affinity of the comparative
preparations are shown in Tables XIV to XVII.
TABLE-US-00014 TABLE XIV Liquid affinity of Askina .RTM. Gel (d):
Agar (absorption) Gelatine (release) liquid affinity liquid
affinity Sample gain of gel weight (%) loss of gel weight (%) 1 28
-4* 2 28 -3 3 28 -3 4 29 -3 5 28 -4 Mean 28 -3 S.sub.rel 1.6% 15.4%
*Sample has not been used for further analysis (film broke)
[0144] The Askina.RTM. Gel exhibits an liquid release of 3%, which
is significantly lower than in the examples a) to c) (see Tables XI
to XIII). The liquid absorption is with 28% higher than in the
examples a) to c). Askina.RTM. Gel is classified as a "type 3a" by
the standards of EN13726-1:2002.
TABLE-US-00015 TABLE XV Liquid affinity of IntraSite .RTM. Gel (e)
Agar (absorption) Gelatine (release) liquid affinity liquid
affinity Sample gain of gel weight (%) loss of gel weight (%) 1 15
-6 2 25 -7 3 13 -7 4 13 -7 5 15 -6 Mean 16 -7 S.sub.rel 31%
8.3%
[0145] The IntraSite.RTM. Gel releases 7% of the liquid to the test
substrate and showed a liquid absorption of 16%. The IntraSite.RTM.
Gel has a lower liquid release capacity than the preparation
according to the invention. IntraSite.RTM. Gel is classified as a
"type 2b" by the standards of EN 13726-1:2002.
TABLE-US-00016 TABLE XVI Liquid affinity of NU-Gel (f): Agar
(absorption) Gelatine (release) liquid affinity liquid affinity
Sample gain of gel weight (%) loss of gel weight (%) 1 29 -2 2 29
-4* 3 29 -2 4 29 -5* 5 29 -2 Mean 29 -2 S.sub.rel 0% 0% *Sample has
not been used for further analysis (film broke)
[0146] The NU Gel exhibits only a very low liquid release of 2%,
while its liquid absorption is determined to be 29%. NU Gel is
classified as a "type 3a" by the standards of EN13726-1:2002.
TABLE-US-00017 TABLE XVII Liquid affinity of Varihesive .RTM.
Hydrogel (g): Agar (absorption) Gelatine (release) liquid affinity
liquid affinity Sample gain of gel weight (%) loss of gel weight
(%) 1 32 -6 2 32 -6 3 32 -6 4 32 -6 5 32 -6 Mean 32 -6 S.sub.rel 0%
0%
[0147] The Varihesive.RTM. Hydrogel revealed a liquid release value
of 6%, which is significantly lower than the release capacity of
the inventive preparations. The liquid absorption is 32%.
Varihesive.RTM. Hydrogel is classified as a "4b type" by the
standards of EN13726-1:2002.
[0148] The liquid affinity tests clearly demonstrates that the
liquid release properties of the preparations according to the
invention are significantly higher than the release characteristics
of the known gels of the prior art.
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