U.S. patent application number 13/468100 was filed with the patent office on 2012-08-30 for mineral technologies (mt) for acute hemostasis and for the treatment of acute wounds and chronic ulcers.
Invention is credited to Gary Lee Bowlin, Marcus E. Carr, Robert F. Diegelmann, Kevin R. Ward.
Application Number | 20120219612 13/468100 |
Document ID | / |
Family ID | 36917001 |
Filed Date | 2012-08-30 |
United States Patent
Application |
20120219612 |
Kind Code |
A1 |
Diegelmann; Robert F. ; et
al. |
August 30, 2012 |
Mineral Technologies (MT) for Acute Hemostasis and for the
Treatment of Acute Wounds and Chronic Ulcers
Abstract
Compositions comprising clay minerals and methods for their use
in promoting hemostasis are provided. The compositions comprise
clay minerals such as bentonite, and facilitate blood clotting when
applied to a hemorrhaging wound. Electrospun or electrosprayed
materials (e.g. bandages, micron beads, etc.) which include clay
minerals, and methods for the treatment of acute hemorrhage, are
also provided.
Inventors: |
Diegelmann; Robert F.; (Bon
Air, VA) ; Ward; Kevin R.; (Glen Allen, VA) ;
Carr; Marcus E.; (Holland, PA) ; Bowlin; Gary
Lee; (Mechanicsville, VA) |
Family ID: |
36917001 |
Appl. No.: |
13/468100 |
Filed: |
May 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11884363 |
Sep 12, 2008 |
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PCT/US06/05251 |
Feb 15, 2006 |
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13468100 |
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60652848 |
Feb 15, 2005 |
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Current U.S.
Class: |
424/447 ;
424/684; 424/94.64 |
Current CPC
Class: |
A61P 23/00 20180101;
A61P 1/00 20180101; A61P 7/04 20180101; A61P 1/04 20180101; A61P
31/00 20180101; A61L 15/18 20130101; A61L 26/0004 20130101 |
Class at
Publication: |
424/447 ;
424/684; 424/94.64 |
International
Class: |
A61L 15/18 20060101
A61L015/18; A61K 38/48 20060101 A61K038/48; A61P 23/00 20060101
A61P023/00; A61P 1/00 20060101 A61P001/00; A61P 1/04 20060101
A61P001/04; A61P 31/00 20060101 A61P031/00; A61K 33/06 20060101
A61K033/06; A61P 7/04 20060101 A61P007/04 |
Claims
1-18. (canceled)
19. A method for promoting hemostasis in internal bleeding in a
subject in need thereof, comprising the step of: applying one or
more clay minerals selected from the group consisting of kaolin and
bentonite to a site of internal bleeding in a subject in need
thereof, said clay minerals being in a quantity sufficient to
promote blood clotting and stanching of blood flow from said
site.
20. The method of claim 19, wherein said internal bleeding is a
location of intentional trauma.
21. The method of claim 19 wherein said internal bleeding is
gastrointestinal bleeding.
22. The method of claim 21 wherein said gastrointestinal bleeding
is at a location of intentional trauma.
23. The method of claim 21 wherein said gastrointestinal bleeding
is associated with one or more ulcers.
24. The method of claim 21 wherein said one or more clay minerals
includes bentonite.
25. The method of claim 19 wherein said one or more clay minerals
includes bentonite.
26. The method of claim 19 wherein said one or more clay minerals
includes kaolin.
27. The method of claim 19 wherein said step of applying is
performed using gauze, said one or more clay minerals being
associated with said gauze, and wherein said gauze is applied to
said site of internal bleeding.
28. The method of claim 27 wherein said site of internal bleeding
is associated with gastrointestinal bleeding.
29. The method of claim 19 wherein said one or more clay minerals
is in a form selected from the group consisting of granules,
powder, liquid, paste, gel, micron beads, impregnated in a bandage,
and electrospun into a bandage
30. The method of claim 19, wherein said step of applying is
performed by placement of a substrate which carries said one or
more clay minerals on or in said site of said internal
bleeding.
31. The method of claim 19, further comprising the step of
simultaneously or sequentially applying to said site of internal
bleeding one or more substances selected from the group consisting
of chitosan, fibrin, fibrinogen, thrombin, superabsorbent polymers,
calcium, polyethylene glycol, dextran, vasoactive catecholamines,
vasoactive peptides, electrostatic agents, antimicrobial agents,
anesthetic agents and fluorescent agents.
32. The method of claim 19 wherein said step of applying allows for
the formation of a cast comprising the one or more clay minerals
and blood from said site of internal bleeding.
33. The method of claim 19 whereby said clotting and stanching of
blood flow from said site without an exothermic reaction.
34. The method of claim 19 wherein said applying step is performed
without zeolite.
35. The method of claim 19 wherein said applying step applies said
one or more clay minerals in powder foam.
36. The method of claim 35 wherein said powder is impregnated in a
bandage which is applied to said site.
37. The method of claim 19 wherein said applying step is performed
by endoscopic delivery.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention generally relates to compositions and methods
for promoting hemostasis. In particular, the invention provides
compositions comprising clay minerals, which, when applied to a
bleeding area, function to 1) absorb liquid and 2) promote blood
clotting.
[0003] 2. Background of the Invention
[0004] Hemorrhagic events, from the minor to the life threatening,
result from a wide variety of circumstances and occur in a wide
variety of settings. The conditions which result in hemorrhage may
be relatively predictable, such as those associated with medical
procedures. Alternatively, hemorrhagic events may result from
unpredictable circumstances, such as a breach of the skin or an
internal organ in an accident. Such acute traumatic wounds occur in
an almost infinite number of patterns and degrees, making the use
of simple compression or application of a single type of bandage,
impractical if not impossible, especially in the most severe
circumstances. For example, a traumatic wound to the groin cannot
be readily controlled either by simple direct pressure or by the
use of a simple flat bandage.
[0005] Attempts have been made which partially address the
treatment of hemostasis, and/or the need for flexibility in wound
dressings: [0006] 1) Hemcon's Chitosan Bandage (see the website
located at hemcon.com) is a gauze bandage impregnated with
chitosan. Chitosan, a fiber derived from chitin in shellfish, is a
nondigestible aminopolysaccharide. Chitosan is synthesized by
removing acetyl groups from chitin, through a process called
deacetylation. Chitosan is known to have significant coagulant
properties which are believed to be based on its cationic (positive
charge) properties. However, its mucoadhesive properties may also
be responsible. In models of life threatening hemorrhage (J Trauma
2005; 59:865-875 and J Trauma 2004; 56:974-983), the ability of the
bandage to improve survival has been limited. In one study, use of
the bandage had a 100% failure rate (isolated arterial injury). In
a second study (combined arterial and venous hemorrhage at low
blood pressures) the bandage resulted in a 28% mortality rate. It
was noted that there was a bandage-to-bandage variability in
performance and ability of the bandage to adhere to the wound. This
bandage is available in only one size and formulation. The ability
to produce a powder or granular form of chitosan similar to that of
QuickClot or the bentonite clay described in this application is
likely to be limited. Powdered chitosan does not mix well with
blood. [0007] 2) The Fibrin Sealant Dressing (FSD) is the result of
a collaborative effort between the U.S. Army and the American Red
Cross. It is made from fibrin, thrombin, and factor XIII purified
from human donated blood and plasma. It is thus a biologic which
has a potential for disease transmission even though this risk is
small. The FSD controls hemorrhage by promoting natural clot
formation at the site of injury since it provides concentrated
coagulation factors at the site of injury. However, it is a
biologic and the manufacture of such bandages is extremely
labor-intensive, and their cost may prohibit routine use in most
circumstances (estimated cost between $500 and $1000). The
dressings are fragile and tend to break apart if not carefully
handled. In a study performed by the U.S. Army (J Trauma 2005;
59:865-875) utilizing a model of severe arterial bleeding, the FSD
bandage significantly improved survival when compared with the Army
Field dressing, QuickClot and the HemCon bandage. The product comes
only in bandage form. [0008] 3) The Rapid Deployable Hemostat (RDH)
is a bandage made by Marine Polymer Technologies and incorporates a
derivative from sea algae to promote hemostasis. However, in a
study by Alam and colleagues (Alam, et al. J Trauma 2003;
54:1077-1082), which explored the ability of many commercial
products to stop severe bleeding and to increase survival, use of
the RDH resulted in lower survival rates than a simple standard
bandage. This would indicate that the current components of the RDH
are not suitable for use in life threatening hemorrhage.
Furthermore, to our knowledge, this product's only available form
is one of a bandage. The cost of this product may be expensive and
is currently estimated to be approximately $300 per unit. [0009] 4)
U.S. Pat. No. 4,748,978 (to Kamp) discloses a therapeutic dressing
that includes a flexible permeable support and a mixture of mineral
components, including bentonite, kaolinite and illite or
attapulgite, and may include anti-fungal (or other) agents as well.
The dressing is reported to be designed to be flexible and to be
able to be made or cut to any desired size. It is reported to be
intended primarily to treat burns, but can also be used for the
treatment of ulcers. However, the dressing is not described as
suitable for the treatment of hemorrhage, and no data from Kamp is
available to support its use for this indictaion. [0010] 5) U.S.
Pat. No. 4,822,349 (to Hursey et al.) describes a non-bandage
material used to treat bleeding. The material is sold by Z-Medica
as "Quick-Clot" (see the website located at z-medica.com) and is a
granular form of zeolite, an aluminum silicate mineral. During use,
it is poured into a wound. In addition to absorbing water from
hemorrhaged blood and concentrating hemostatic factors in the blood
at the site of injury, its mechanism of action appears to involve
chemical cautery. An intense exothermic reaction is produced upon
contact with liquid (e.g. blood), and is likely responsible for
stoppage of blood flow by cauterization. While use of this material
may be preferable to bleeding to death, the attendant burning of
tissue at and near the wound (and possible burn injury of medial
personnel who are administering the material) is clearly a severe
disadvantage. This side effect also reduces the ability of the
material to be used for internal hemorrhage. While the manufacturer
indicates that the main mechanism of action is the superaborbant
nature of zeolite which absorbs water out of blood to concentrate
clotting factors, the patent (U.S. Pat. No. 4,822,349 (to Hursey et
al.) indicates that its action lies mainly through the exothermic
reaction it creates. Studies by Alam and colleagues (J Trauma 2004;
56:974-983) clearly demonstrate that the ability of this product to
stop hemorrhage is quickly lost when it is partially hydrated in
attempts to reduce the exothermic reaction and the resulting
temperature it produces in tissues. When the granules are placed in
a bag similar to a tea bag to facilitate removal, its ability to
stop bleeding is significantly limited. In addition, to our
knowledge this product has not been made into a bandage and even if
it were it would likely still produce a significant exothermic
reaction upon contact with blood. [0011] 6) A product made by
TraumaDex (see the website located at traumadex.com) is also a
non-bandage. In this case, the product is a powder consisting of
microporous beads which absorb water and which contain concentrated
clotting factors. During use, the material is poured or squirted
into the wound. However, when studied by Alam and colleagues (J
Trauma 2003; 54:1077-1082) in a model of severe hemorrhagic shock,
TraumaDex performed no better than a standard field dressing, thus
offering no advantage and certainly more expense. Alam and
colleagues studied this product again (J Trauma 2004; 56:974-983)
and demonstrated its performance to be suboptimal compared to
QuickClot and the Hemcon bandage. In this study, it performed only
slightly better than a standard dressing. Also to our knowledge,
this product has not been made into a bandage and even if it were
it would probably lack efficacy in stopping severe bleeding.
[0012] A "one size fits all" approach to the treatment of
hemorrhage clearly does not and cannot work, and the prior art has
thus far failed to provide compositions and methods to treat
hemorrhage that are inexpensive, efficacious, highly adaptable,
easy to use, and lacking in serious side effects.
SUMMARY OF THE INVENTION
[0013] The invention is based on the surprising discovery that
formulations comprising certain relatively inexpensive and readily
available clay minerals are highly effective in promoting blood
clotting and stanching the flow of blood when applied to a
hemorrhaging wound. Application of the material does not cause an
exothermic reaction upon contact with the liquid components of
blood. Thus, there is no danger of possible tissue damage by
burning. The compositions of the invention can thus be used safely
in any situation that requires the treatment of hemorrhage,
including internal bleeding. An exemplary type of such a clay
mineral is bentonite.
[0014] The present invention provides compositions comprising clay
minerals and methods for their use for effectively treating and
controlling hemorrhage in a large number of variable scenarios. The
compositions are relatively inexpensive to manufacture, highly
effective, highly adaptable and easy to use, and cause no serious
side effects. The clay mineral compositions provided herein can be
used in a flexible manner to treat hemorrhage under a wide-ranging
variety of circumstances.
[0015] It is an object of this invention to provide a method of
promoting hemostasis in a hemorrhaging wound. The method comprises
the step of applying a composition comprising one or more clay
minerals to the hemorrhaging wound. The clay minerals are applied
in a quantity sufficient to promote one or both of the following:
i) hemostasis and ii) formation of a cast (e.g. a hardened plug)
comprising the one or more clay minerals and blood from the
hemorrhaging wound. The one or more clay minerals may be selected
from the group consisting of kaolin-serpentine type clays, illite
type clays and smectite type clays. In one embodiment, the one or
more clay minerals is bentonite. The one or more clay minerals may
be in a form such as, for example, granules, powder, micron beads,
liquid, paste, gel, impregnated in a bandage, and electospun into a
bandage. The composition may further comprise one or more
substances such as, for example, superabsorbent polymers, chitosan,
fibrin(ogen), thrombin, calcium, vasoactive catecholamines,
vasoactive peptides, electrostatic agents, antimicrobial agents,
anesthetic agents, fluorescent agents, and quick dissolve carrier
polymers such as dextran and polyethylene glycol (PEG). The
hemorrhaging wound that is treated may be an external wound or an
internal wound. The wounds may be the result of accidental or
intentional trauma or by tissue breakdown from disease. Examples of
tissue breakdown leading to severe bleeding include
gastrointestinal bleeding as a result of ulcers, among others.
Intentional trauma includes trauma that occurs as a result of
surgical manipulation of tissue, due to, for example, repair of the
tissue, repair or removal of adjacent tissue, the need to
surgically insert or remove medical devices, etc.
[0016] The invention further provides an electrospun fiber
comprising one or more clay minerals. The one or more clay minerals
may be, for example, kaolin-serpentine type clays, illite type
clays and smectite type clays. In one embodiment, the one or more
clay minerals is bentonite. The electrospun fiber may further
comprising one or more substances such as, for example, gelatin, a
super-absorbent polymer, chitosan, fibrin(ogen), thrombin, calcium,
vasoactive catecholamines, vasoactive peptides, antimicrobial
agents, anesthetic agents and fluorescent agents. The electrospun
fiber may be crosslinked.
[0017] The invention also provides a method of making an
electrospun fiber, comprising the steps of 1) forming a composition
comprising one or more clay minerals and a solvent, and 2)
electrospinning the composition to form the electrospun fiber. In
one embodiment, the solvent is 2,2,2-trifluoroethanol. The
composition to form the electrospun fiber may further comprise one
or more substances such as, for example, gelatin, a super-absorbent
polymer, chitosan, fibrin(ogen), thrombin, calcium, vasoactive
catecholamines and vasoactive peptides. The method may further
comprise the step of crosslinking the electrospun fiber.
[0018] In yet another embodiment, the invention provides a bandage
comprised of electrospun fibers, wherein the electrospun fibers
comprise one or more clay minerals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1. Schematic representation of exemplary
electrospinning apparatus.
[0020] FIG. 2: Product obtained from electrospinning of gelatin
alone (200 mg/mL of 2,2,2-trifluoroethanol, TFE).
[0021] FIG. 3: Product obtained from electrospinning of gelatin
(200 mg/mL TFE) with pulverized bentonite clay (300 mg/mL TFE).
[0022] FIG. 4: Product obtained from electrospinning of gelatin
(200 mg/mL TFE), pulverized bentonite clay (300 mg/mL) and a blend
of crosslinked sodium salt of polyacrylic acid with particle size
distribution less than 300 microns (LiquiBlock 144: Emerging
Technologies Inc. Greensboro N.C.) (100 mg/mL TFE).
[0023] FIG. 5: Product obtained from electrospinning of gelatin
(200 mg/mL TFE) and Bentonite Clay Powder (300 mg/mL TFE).
[0024] FIG. 6: Product obtained from electrospinning of gelatin
(200 mg/mL TFE), Bentonite Clay Powder (300 mg/mL TFE) and sodium
salt of polyacrylic acid with particle size distribution less than
300 microns (100 mg/mL TIE).
[0025] FIG. 7. A-C. Coagulation studies with bentonite. A, effect
of bentonite on platelet function; B, effect of bentonite of clot
structure; C, Thromboelastograph (TEG.RTM.) data with varying
concentrations of bentonite.
[0026] FIG. 8A-C. Coagulation studies with bentonite compared to
fibrinogen. A, Effects of bentonite and fibrinogen on platelet
function; B, effects of electrospun materials on clot structure; C,
Thromboelastograph (TEG.RTM.) data.
[0027] FIGS. 9A and B. Comparison of bentonite, gelatin and
zeolite. A, effect of 10 mg/mL of these agents on platelet
function; B, effect of 10 mg/mL of these agents on clot
structure.
[0028] FIG. 10A-B. Comparison of bentonite, gelatin and zeolite. A,
effect of 50 mg/mL of these agents on platelet function; B, effect
of 50 mg/mL of these agents on clot structure.
[0029] FIG. 11A-E. Thromboelastograph (TEG.RTM.) data for
bentonite, gelatin and zeolite. A, 10 gm/mL; B, 50 mg/mL; C, 75
mg/mL; D, zeolite at 10, 50 and 75 mg/mL; E, bentonite at 10, 50
and 75 mg/mL.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0030] The present invention provides compositions comprising clay
minerals and related materials, and methods for their use in
treating and controlling hemorrhage, i.e. in promoting hemostasis.
By "hemorrhage" or "acute hemorrhage" we mean the loss of blood
from one or more anatomical sites of a patient that, if left
untreated, would jeopardize the health of the patient. Hemorrhage
typically results from rupture of one or more blood vessels, which
may occur accidentally (e.g. as in accidental wounds) or
purposefully (e.g. during surgical procedures). The active control
of hemorrhage is referred to as "hemostasis". The promotion of
hemostasis involves, for example: slowing or stanching the flow of
blood; and enhancing, facilitating or causing the blood to clot,
particularly at the site of a wound.
[0031] The word "clay" has no standard definition among the various
fields to which it applies (e.g. geology, minerology, etc.).
However, those skilled in the relevant arts generally recognize
that clay is a very fine grained inorganic mineral material that is
plastic when wet, and that hardens when dried. Most clays, having
been formed by the weathering of silicate minerals in igneous
rocks, are included in the silicate class of minerals and the
subclass phyllosilicates. Phyllosilicates are formed from
continuous sheets of tetrahedra, the basic unit of which is
(Si.sub.2O.sub.5).sup.-2. Phyllosilicates in turn contain the clay
group, comprised of hydrous layered silicates in which Al
substitutes for some of the Si, the basic unit being
(AlSi.sub.3O.sub.10).sup.-5. Clay minerals generally exhibit high
aqueous absorption capacities. However, unlike some silicate
minerals (such as zeolite of the tectosilicate subclass),
phyllosilicates and clays do not react exothermically in the
presence of liquid.
[0032] The present invention is based in part on the surprising
discovery that clay minerals and related materials are highly
effective in causing rapid blood clotting. Thus, they are excellent
candidates for use in compositions and methods to treat hemorrhage.
In addition, clay minerals are readily available and relatively
inexpensive, and they are amenable to manipulation into a variety
of forms.
[0033] By "clay minerals and related materials" we mean naturally
occurring or synthetic inorganic material that exhibits the
properties of clay minerals, e.g. the material is mineral in
nature; dry forms of the material exhibit high aqueous absorption
capacities; the material exhibits plasticity (ability to be molded)
when particulate forms of the material are mixed with aqueous-based
liquid; the material is devoid of exothermic activity when mixed
with aqueous-based liquid; the material causes rapid clotting of
blood. In preferred embodiments of the invention, the materials
utilized in the practice of the invention are clay minerals such as
various forms of kaolinite-serpentine type clays, illite type clays
and smectite type clays, etc. or combinations thereof. Materials
related to clay minerals which may be used in the practice of the
invention include but are not limited to volcanic ash (a precursor
of mineral clay) and other similar natural and synthetic minerals,
compounds and clays.
[0034] In one embodiment of the invention, the materials are
naturally occurring hydrated aluminum silicates referred to as
bentonites. Bentonite is comprised of a three layer structure with
alumina sheets sandwiched between tetrahedral silica units.
Simplified formulas for bentonite are: 1)
(OH).sub.2Al.sub.2Si4O.sub.10; and 2)
Al.sub.2O.sub.3.4SiO.sub.2.H.sub.2O. Bentonite is a plastic clay
generated from the alteration of volcanic ash, and consists
predominately of smectite minerals, especially montmorillonite.
Bentonite synonyms include sodium bentonite, calcium
montmorillonite, saponite, montmorillonite sodium, montmorillonite
calcium, taylorite, aluminum silicate, fuller's earth, and others.
There are three major types of bentonite: 1) natural calcium
bentonite; 2) natural sodium bentonite; and 3) sodium activated
bentonite. In general, sodium activated bentonites have superior
swelling and gelling properties compared to calcium bentonites. The
term "bentonite" as used herein in intended to encompass all
synonyms and all types of bentonite, unless otherwise
specified.
[0035] Commercial, food, and pharmaceutical grade bentonites are
readily available, as are a variety of particle or mesh sizes.
Current uses of bentonite include the following: foundry sand,
paints, thickening, suspending, sealing, bonding, binding,
emulsification, absorption, moisture retention, carriers, water
proofing, water filtering and detoxification, beverage, food, and
cosmetics. Because of it absorptive and clumping ability, one of
the most common uses of bentonite clay has been for cat litter.
[0036] Bentonite clay in various forms and mixtures is also
promoted as a detoxifying agent when orally consumed. It appears to
have the ability to absorb potential toxins through its structure
and ionic charges. It has been postulated that it may also have
anti-proteolytic effects. These properties would also contribute to
the treatment of acute and chronic wounds to promote healing,
prevent infection, and to control pain. Furthermore, because
bentonite clay is known to be consumed without ill effects, its use
to treat gastrointestinal or other internal hemorrhaging would be
expected to be safe.
[0037] In another embodiment of the invention, the mineral clay
that is used is kaolin (anhydrous aluminum silicate). One known use
of kaolin is in the common coagulation test called the "activated
partial thromboplastin time" which is a measure of the activity of
the intrinsic clotting system. The activator for this test is
kaolin.
[0038] Clay minerals have been found to have a remarkable and
unexpected ability to cause blood to clot. Even heparinized blood
will clot in their presence. Without being bound by theory, it is
noted that the distribution of cations and anions in this type of
material may cause favorable hemostasis, since cationic species are
known to cause red cell aggregation and hence clotting, perhaps
through a cation exchange mechanism. The negative charge of the
clay may activate the intrinsic clotting system because a negative
charge is known to possess this ability. The structural composition
of the mineral along with its ionic distribution of charges also
provides impressive absorptive properties. In terms of hemorrhage,
this would provide for rapid absorption of blood components which
may concentrate intrinsic clotting factors, including platelets, at
the site of injury.
[0039] The clay mineral compositions utilized in the present
invention may include one or more clay minerals, i.e. a mixture of
clays may be utilized. Those of skill in the art will recognize
that such mixtures may occur naturally, in that deposits of mineral
clays may or may not be of purely one type. Alternatively, the
mixtures may be formed purposefully during production of the
compositions.
[0040] The clay mineral compositions utilized in the practice of
the present invention may be formulated in a variety of ways.
Examples include but are not limited to liquids, foams, powders,
granules, gels, hydrogels, sprays, incorporation into bandages,
etc. Depending on the application, such formulations may vary, for
example, in viscosity, particle size, etc. In addition, a variety
of other compounds or materials may be added to the clay minerals,
examples of which include antimicrobial (e.g. anti-biotic,
anti-fungal, and/or anti-viral) agents, electrostatic agents (e.g.
dendrimers in which the charge density is varied or similar
compounds), preservatives, various carriers which modulate
viscosity (e.g. for a spray formulation), various colorants, and
various medicaments which promote wound healing. Other appropriate
hemostatic or absorptive agents may also be added. These include
but are not limited to chitosan and its derivatives, fibrinogen and
its derivatives (represented herein as fibrin(ogen), e.g. fibrin,
which is a cleavage product of fibrinogen, or super-absorbent
polymers of many types, cellulose of many types, other cations such
as calcium, silver, and sodium or anions, other ion exchange
resins, and other synthetic or natural absorbent entities such as
super-absorbent polymers with and without ionic or charge
properties. In some embodiments of the invention, cations of one
type in the clay may be substituted with cations of another type
(e.g. silver cations), the latter having a more favorable clotting
activity.
[0041] In addition, the clay mineral may have added to it
vasoactive or other agents which promote vasoconstriction and
hemostasis. Such agents might include catecholamines or vasoactive
peptides. This may be especially helpful in its dry form so that
when blood is absorbed, the additive agents become activated and
are leached into the tissues to exert their effects. In addition,
antibiotics and other agents which prevent infection (any
bacteriocidal or bacteriostatic agent or compound) and
anesthetics/analgesics may be added to enhance healing by
preventing infection and reducing pain. In addition, fluorescent
agents or components could be added to help during surgical removal
of some forms of the mineral to ensure minimal retention of the
mineral after definitive control of hemorrhage is obtained. These
could be viewed during application of light for example from a
Wood's lamp. In short, any suitable material may be added, so long
as the mineral clay composition is still able to cause blood
clotting and promote hemostasis.
[0042] The formulations of the present invention may be
administered to a site of bleeding by any of a variety of means
that are well known to those of skill in the art. Examples include
but are not limited to internally (e.g. by ingestion of a liquid or
tablet form), directly to a wound, (e.g. by shaking powdered or
granulated forms of the material directly into or onto a site of
hemorrhage), by placing a material such as a bandage that is
impregnated with the material into or onto a wound, by spraying it
into or onto the wound, or otherwise coating the wound with the
material. Bandages may also be of a type that, with application of
pressure, bend and so conform to the shape of the wound site.
Partially hydrated forms resembling mortar or other
semisolid-semiliquid forms, etc. may be used to fill certain types
of wounds. For intra-abdominal bleeding, we envision puncture of
the peritoneum with a trocar followed by administration of clay
mineral agents of various suitable formulations. Formulations may
thus be in many forms such as bandages of varying shapes, sizes and
degrees of flexibility and/or rigidity; gels; liquids; pastes;
slurries; granules; powders; and other forms. The clay minerals can
be incorporated into special carriers such as liposomes or other
vehicles to assist in their delivery either topically,
gastrointestinally, intracavitary, or even intravascularly. In
addition, combinations of these forms may also be used, for
example, a bandage that combines a flexible, sponge-like or gel
material that is placed directly onto a wound, and that has an
outer protective backing of a somewhat rigid material that is easy
to handle and manipulate, the outer layer providing mechanical
protection to the wound after application. Both the inner and outer
materials may contain clay minerals. Any means of administration
may be used, so long as the mineral clay makes sufficient contact
with the site of hemorrhage to promote hemostasis.
[0043] In yet another embodiment of the invention, the mineral clay
is incorporated into a fiber-like material for use in bandages
using the technique of electrospinning. Electrospinning involves
drawing a solution, usually liquid polymers dissolved in solvents,
through a small nozzle within a high-energy electric field. The
charged solution forms a liquid jet as it moves out the nozzle
toward a grounded target, such as a metal plate or rod. During
liquid jet travel, the solvent evaporates, forming a solid fiber
that collects on the target as a non-woven "fabric" or
mat/scaffolding. The main advantages of this polymer fiber
processing technique are that it is fairly simple, scalable,
efficient, and rapid (requires only minutes to create complex
structures). An exemplary electrospinning system is illustrated in
FIG. 1. This configuration permits the creation of scaffolds with
micro- to nano-scale fibers. Additionally, random or highly aligned
(high mandrel rotational speeds with fibers aligned
circumferentially) fiber structures can be fabricated. The major
factor in controlling fiber diameter is the polymer solution
concentration. A linear relationship exists between polymer
concentration and polymer fiber diameters produced, with a lower
concentration resulting in finer fiber diameters.
[0044] In the case of electrospinning clay minerals, the mix of
materials that is electrospun will, in general include, in addition
to the mineral clay, a carrier polymer (natural and/or synthetic)
for the insoluble clay, a solvent to dissolve the carrier
polymer(s), and/or an absorbent polymer. The addition of an
absorbent polymer facilitates exposure of the blood to the entire
structure of the electrospun fibrous material (e.g. bandage) and
not just the surface of the material that is in contact with the
blood. Possible additives to electrospun material include those
which can be added to other clay mineral compositions and
materials, as described above.
[0045] In an alternative embodiment, beads in the micron size range
may be formed from compositions of the present invention. Those of
skill in the art will recognize that by lowering polymer
concentrations, a solution results which may be electrosprayed
(rather than electrospun), and the product that results is in the
shape of micron-sized balls or beads. Such beads may be used in the
practice of the invention in much the same way as pulverized
bentonite is used (e.g. poured into a wound). However, such
electrosprayed beads may also contain other substances which are
beneficial for blood clotting and/or wound healing, since they can
be made from compositions that contain such substances, as
described above for electrospun compositions. Electrosprayed beads
can thus be used, for example, for the release (e.g. slow release)
of such beneficial compounds at the site of a wound to which they
are applied.
[0046] Compositions comprising clay minerals may be utilized to
control bleeding in a large variety of settings, which include but
are not limited to: [0047]a) External bleeding from wounds (acute
and chronic) through the use of liquids, slurries, gels, sprays,
foams, hydrogels, powder, granules, or the coating of bandages with
these preparations. [0048]b) Gastrointestinal bleeding through the
use of an ingestible liquid, slurry, gel, foam, granules, or
powder. [0049]c) Epistaxis through the use of an aerosolized
powder, sprays, foam, patches, or coated tampon. [0050]d) Control
of internal solid organ or honey injury through the use of liquids,
slurries, sprays, powder, foams, gels, granules, or bandages coated
with such. [0051]e) Promotion of hemostasis, fluid absorption and
inhibition of proteolytic enzymes to promote healing of all types
of wound including the control of pain from such wounds.
[0047] Many applications of the present invention are based on the
known problems of getting the surfaces of bandages to conform to
all surfaces of a bleeding wound. The use of granules, powders,
gels, foams, slurries, pastes, and liquids allow the preparations
of the invention to cover all surfaces no matter how irregular they
are. For example, a traumatic wound to the groin is very difficult
to control by simple direct pressure or by the use of a simple flat
bandage. However, treatment can be carried out by using a clay
mineral in the form of, for example, a powder, granule preparation,
gel, foam, or very viscous liquid preparation that can be poured,
squirted or pumped into the wound, followed by application of
pressure. One advantage of the preparations of the present
invention is their ability to be applied to irregularly shaped
wounds, and for sealing wound tracks, i.e. the path of an injurious
agent such as a bullet, knife blade, etc.
EXAMPLES
Example 1
Electrospinning Gelatin, Bentonite and Super-Absorbent Polymer
[0048] To create a hemostatic bandage, gelatin (Sigma Aldrich
#G-9391), as a basic structural element (carrier polymer) was
utilized for its potential to quickly dissolve in the wound (if
desired and not cross-linked), promote some degree of coagulation,
and act as a delivery system for bentonite, and/or quick absorb
polymers. When electrospinning gelatin, a concentration of anywhere
between 80 mg/mL to 300 mg/mL in 2,2,2-trifluoroethanol (TFE)
(Sigma Aldrich #T-8132) can be utilized. For this experiment, a
larger gelatin concentration was desirable because it had the
ability to hold/suspend particles that were added to the solution.
Both bentonite and super-absorbent polymer particles were added to
the solution. ExquisiCat..RTM.. Extra Strength SCOOP, premium
clumping cat litter, unscented, was utilized as the source of
bentonite, and was added to the gelatin solution to increase liquid
absorbency and coagulation ability of the scaffold. For the
bentonite, the pellets were placed in a mortar and pestle, and
ground (pulverized) until smaller particle-size pieces were
achieved. By this process, no large pieces remained before adding
it to the gelatin solution. Normally when electrospinning, a
18-guage needle is used, but for this experiment, a 14-guage needle
was necessary in order to allow the ground bentonite and
super-absorbent polymer particles to pass through the needle
tip.
[0049] The concentration of gelatin that was chosen for
electrospinning ranged between 150 mg/mL to 250 mg/mL TFE. When
constructing the electrospun bandages, 3 mL of solution was
sufficient to obtain a sample, but 5 mL was necessary when spinning
onto a larger mandrel to create a full bandage. FIG. 2 shows a
scanning electron micrograph (SEM) of electrospun gelatin alone at
a concentration of 200 mg/mL TFE.
[0050] The optimal concentration of ground bentonite to be put into
the gelatin solution was determined. Concentrations ranging from
100 mg/mL to 400 mg/mL of ground bentonite were added to the
gelatin solution to determine the highest concentration possible
that could be put into the gelatin without clogging the syringe or
having all of the particles sink to the bottom of the vial when
pulling the solution into the syringe for electrospinning. The
highest concentration of pulverized bentonite that allowed for
successful electrospinning was 300 mg/mL in the gelatin solution,
and this concentration was utilized throughout.
[0051] The gelatin solution with suspended bentonite was spun at
different flow rates, beginning at a slower rate of 4 mL/hr and
increasing it to 45 mL/hr. Going too fast would cause the solution
to no longer spin and constantly drip, but if the solution were
spun slower the litter particles would all sink to the bottom of
the syringe. The optimal flow rate to spin the bentonite and
gelatin was in the range of 5 to 10 mL/hr. It was also spun at
different distances between the syringe needle and the mandrel,
beginning at 9.5 inches away and then getting closer at 5 inches.
The final distance of 6 inches was determined to give the best end
result. FIG. 3 shows a SEM of gelatin with the pulverized
bentonite.
[0052] The next step was testing the different super-absorbent
polymers (blends of crosslinked polyacrylic acid and their salts)
for their absorbency. Each polymer was placed in 3 mLs of water and
timed to determine how long it took each polymer to form a gel.
From these tests, the three polymers that gelled the quickest were
chosen for the experiment to create a "quick" absorb bandage. The
three chosen, Norsocryl XFS, LiquiBlock 144, and Norsocryl s-35,
were based on their particle distribution size (less than 200
microns, 300 microns, and 500 microns, and, respectively). These
polymers were individually added to gelatin samples and
electrospun. A maximum of 100 mg/mL of the super-absorbent polymers
remained suspended in the gelatin solution; therefore, this is the
concentration that was utilized throughout the experiment for all
polymers. A solution of 200-250 mg/mL of gelatin in TFE and 100
mg/mL of polymer were added to the solution that was spun. This
solution was spun without the addition of bentonite to determine
how much water the scaffolds would absorb during a 30-second
exposure to water. After testing each electrospun polymer/gelatin
scaffold, ground bentonite clay was then added to the solution and
electrospun. The same ratios of each substance were maintained: 100
mg/mL of the super-absorbent polymer, 300 mg/mL of ground bentonite
clay, and 250 mg/ml of gelatin in TFE. The faster the rate each one
was electrospun, the tougher and more cast-like the scaffold was;
when the sample was spun more slowly, the scaffold had more of a
cotton-like appearance. Each sample was spun once at 4 mL/hr and
then again at 10-15 mL/hr.
[0053] After each sample was collected, it was put through a
hydration test to determine the percentage of water it could absorb
during a 30 second exposure. The bandages were tested in both fixed
(cross-linked) and un-fixed states. The cross-linking method
utilized was a 30-minute glutaraldehyde vapor fixation. For the
cross-linking, small bandage/fabric samples were placed in a 100 mm
diameter Petri dish containing a 35 mm diameter Petri dish filled
with 50% glutaaldehyde solution. Once the bandage sample was in
place, the lid to the larger Petri dish was put into place to
create an enclosed saturated glutaraldehyde vapor environment for
cross-linking. The fluid component never comes into direct contact
with the bandage structure.
[0054] When spun at a higher flow rate (10 or 15 mL/hr) the
polyacrylic acid with a particle size distribution less than 300
microns produced a scaffold with a cast-like appearance, whereas
when it was spun at a slower flow rate (4 mL/hr) it was more
cotton-like, but was difficult to remove from the mandrel. A
solution spun at 10 mL/hr with 300 mg/mL of bentonite clay, 250
mg/mL gelatin in TFE, and 100 mg/mL of the same polyacrylic acid
had a 776% increase in weight when placed into water for 30
seconds, for an un-fixed scaffold, and a 1508% increase in weight
for the same scaffold in the cross-linked state. Further, this
sample retained its shape when exposed to water.
[0055] The sample utilizing the cross-linked polyacrylic acid (and
its salt) of less than 500 micron particle size (plus 250 mg/mL
gelatin in TFE and 300 mg/mL ground bentonite) had a cotton-like
appearance regardless of the flow rate at which the sample was
electrospun. The scaffold formed from this sample also absorbed
more water in comparison to that formed with the previous sample
(polyacrylic acid with a particle size distribution less than 300
microns), showing a 1914% increase in weight when it was
cross-linked. However, of the three polymers tested, this sample
was also the most apt to dissolve when exposed to water. In fact, a
sample could not be collected for measurement of water absorption
when it was in the un-fixed state due to complete dissolution.
[0056] The samples produced with a cross-linked polyacrylic acid
(and its salt) of less than 200 micron particle size exhibited high
increases in weight percentage of 2623% for the fixed scaffold and
2114% for the un-fixed scaffold; however, the shape of this sample
was not well retained upon exposure to water.
[0057] Due to its high level of water absorbency, coupled with
excellent shape retention, the super-absorbent polymer chosen for
further investigation as an addition to the gelatin/bentonite clay
solution was that made with cross-linked polyacrylic acid (and its
salt) of less than 300 micron particle size. FIG. 4 shows is a SEM
of electrospun gelatin with pulverized bentonite clay and this
superabsorbent polyacrylic acid.
[0058] The original bentonite utilized in these experiments was in
the form of coarse pellets which were ground into fine pieces that
were easily suspended in the gelatin solution. Another material
that is similar to this, bentonite clay powder (Kalyx.com, Item
#2194), was also utilized. Bentonite clay is available in powder
size particles and was suspended into the gelatin solution much
more efficiently because the particles were so small. Therefore,
the bentonite did not fall out of solution when pulling it into the
syringe or during electrospinning. When this clay powder was used
for electrospinning, the final scaffold generally had a soft,
cottony texture, regardless of the electrospinning rate, though
this need not always be the case. The clay powder and gelatin
solution was electrospun with and without the addition of the less
than 300 micron particle size cross-linked polyacrylic acid. The
resulting scaffolds were tested both in a fixed and un-fixed form
to determine the increase in weight when placed in water for 30
seconds. When comparing the scaffolds constructed with the coarse
bentonite from cat litter verses the bentonite clay powder, the
bentonite clay powder bandages fell apart more easily when
un-fixed, but when fixed this scaffold absorbed more water and
retained its shape better than scaffolds constructed with
pulverized coarse bentonite. FIGS. 5 and 6 show two SEMs of
bentonite clay powder, one with the less than 300 micron particle
size cross-linked polyacrylic acid (FIG. 5) and one without (FIG.
6).
[0059] Thus, one preferred bandage is electrospun from a
composition made with a concentration of 200 mg of gelatin per mL
of TFE, 300 mg of bentonite clay powder per mL of the gelatin
solution, and 100 mg of cross-linked polyacrylic acid (and its
salts) of less than 300 micron particle size (LiquiBlock 144) per
mL of the gelatin solution (FIG. 6). The bandage/scaffold is fixed
for a minimum of about 30 minutes with a glutaraldehyde vapor. This
embodiment of the scaffold exhibited a 2413% increase in weight
when placed in 3 mL of water for 30 seconds. Further, the scaffold
did not lose its shape upon exposure to water.
Example 2
Coagulation Studies
Materials and Methods
[0060] Study materials for Parts I-IV were as follows: Part I:
pulverized bentonite or gelatin; Part II, electrospun fibroginogen,
bentonite, or gelatin; Part III: pulverized bentonite, gelatin, and
zeolite; and Part IV, pulverized bentonite and zeolite. Pulverized
cat litter (as above in Example 1) was the source of bentonite.
Gelatin was obtained from Sigma Aldrich (catalog #G-9391). Zeolite
(Quickclot) was obtained from Z-Medica.
Determination of Platelet Function and Clot Structure Parameters
Using the HAS.TM.
[0061] Hemodyne Hemostasis Analyzer (HAS.TM.) provides a global
evaluation of the integrity of the coagulation system by reporting
the parameters force onset time (FOT), platelet contractile force
(PCF), and clot elastic modulus (CEM). In this instrument a small
sample of whole blood is trapped between to parallel surfaces.
Clotting is initiated by addition of a variety of clotting agents.
During clot formation a downward force is imposed from above and
the degree of deformation is directly measured by a displacement
transducer. From this measurement, elastic modulus is calculated.
As the clot forms, the platelets within the clot attempt to shrink
the clot in the process known as clot retraction. The forces
produce pull on the movable upper plate and the subsequent
deflection is detected by the displacement transducer. The elastic
modulus serves as a calibration constant for conversion of the
displacement signal to force. A software package continually makes
the calculations and plots clot elastic modulus (CEM--Kdynes per
cm.sup.2) and platelet contractile force (PCF--Kdynes) as a
function of time. CEM is a complex parameter that is sensitive to
changes in clot structure, fibrinogen concentration, the rate of
fibrin production and red cell flexibility. PCF is a thrombin
dependent function of platelets. It is sensitive to the rate of
thrombin production, the presence of thrombin inhibitors, and the
degree of GP IIb/IIIc exposure. The measurement is typically
terminated at 20 minutes.
[0062] All clots were formed using 700 .mu.L of citrated whole
blood. Clotting was initiated at time zero by adding CaCl.sub.2 and
increasing amounts of study material (pulverized bentonite or
gelatin). Final clotting conditions included: CaCl.sub.2 10 mM, pH
7.4, ionic strength 0.15M and a final volume of 0.750 mL. Final
material concentrations in the blood samples were 0, 10, 50 and 75
mg/mL. The force onset time (FOT) was determined from the initial
upswing in force and elastic modulus. Platelet function was
subsequently assessed as the force developed after 20 minutes of
measurement. Force (PCF) was recorded in kilodynes. Clot structure
was assessed by concurrently measuring the clot elastic modulus
(CEM). CEM was reported in kilodynes per cm.sup.2.
Definition of HAS Parameters:
[0063] FOT is the speed at which thrombin is generated in whole
blood. PCF is the force produced by platelets during clot
retraction and therefore a measure of platelet function during
clotting. CEM is measured simultaneously with PCF and it reflects
the structural integrity of the clot. Very low PCF, low CEM, and
prolonged FOT is associated with increased bleeding risk. CEM is
the best overall measure of clot integrity and strength.
Determination of Thromboelastographic Parameters Using the
TEG1.RTM.:
[0064] The Thromboelastograph1.RTM.. Coagulation Analyzer 5000
(TEG1.RTM.) measures the response to shearing of a formed clot; a
pin, inserted into a rotating cup containing whole blood moves with
the cup as the fibrin polymerizes. The amount of movement of the
pin is recorded as amplitude, which reaches a maximum. The stronger
the clot, the more the pin moves with the cup and the higher the
maximum amplitude (MA) or clot strength. Both fibrin polymerization
and platelet contraction contribute to the MA.
[0065] Assays were done as follows: Increasing amounts of study
material followed by 20 .mu.L of 0.2M CaCl.sub.2 and 340 .mu.L of
sodium citrated whole blood were added to the sample cup. Final
material concentrations in the blood samples were 0, 10, 50 and 75
mg/mL. Electrospun samples were evaluated at 5 mg/mL. Clot
formation was initiated.
Definition of Thromboelastograph Parameters:
[0066] The reaction time (R) is the time interval between the
addition of sample to the cup and the production of a signal of at
least 2 mm amplitude. The R value is typically interpreted as the
time required for initial fibrin formation. The signal maximum
amplitude (MA) is a reflection of the maximum structural integrity
obtained by the clot. It is dependent on fibrin content, fibrin
structure, platelet concentration and platelet function. The shear
elastic modulus strength (G) is a calculated parameter.
G=5000MA/(100-MA). A thromboelastogram can be performed which
provides a visual inspection of this process.
Part I.
Study Description
[0067] The specific aims of this study were to 1) Determine if
bentonite and gelatin are capable of altering blood clotting
parameters and 2) Compare the clotting capabilities of increasing
concentrations of bentonite, and gelatin. The results are depicted
in Table 1 and FIGS. 7A-C.
TABLE-US-00001 TABLE 1 Hemodyne HAS TEG Final CEM G Concentration
POT PCF (Kdynes/ R MA (Dynes! (mg/mi) (miii) (Kdynes) cin2) (miii)
(mm) sec) Bentonite 0 8 6.90 22.64 7.8 57.5 6765 10 4 10.52 44.03
4.3 61.0 7821 50 2.5 13.44 50.10 3.8 62.0 8158 75 1 17.38 78.11 3.6
61.0 7821 Gelatin 0 8 6.90 22.64 7.8 57.5 6765 10 3 9.10 26.93 3.3
62.0 8158 50 3 13.23 42.72 3.3 59.0 7195 75 0 15.08 35.99 na na na
na = Preclotted sample; unable to obtain valid results.
CONCLUSIONS: In this study, the interactions of bentonite and
gelatin with whole blood have been evaluated. The results indicate
that both materials produce concentration dependent shortening of
the onset of clotting affecting the parameters of PCF and ECM. The
TEG values of increasing concentrations of bentonite are shown in
FIG. 7C. The results also demonstrate that shortening of the onset
of clotting leads to enhanced clot structural integrity.
Part II.
Study Description
[0068] The specific aims of this study were to 1) Determine if
electrospun bentonite, gelatin and fibrinogen are capable of
altering blood clotting parameters and 2) Compare the clotting
capabilities of increasing concentrations of bentonite, gelatin and
fibrinogen. The results are shown in Table 2 and in FIGS. 8A-C.
TABLE-US-00002 TABLE 2 Hemodyne HAS TEG Final CEM 0 Cone. FOT PCF
(Kdynes/ R MA (Dynes/ (mg/mi) (n~in) (Kdynes) em.sup.2) (nun) (mm)
see) Baseline 0 5.5 7.42 30.23 5.5 64.0 8889 Fibrunogen 90 5 4.5
9.37 30.00 5.7 64.5 9085 Fibrinogen 1202 5 3.5 9.69 31.56 4.3 67.5
10385 Fibrunogen 5 3.0 12.20 44.03 3.3 68.5 10873 150~ Gelatin 200~
5 3.0 7.74 43.09 3.9 64.0 8889 Gelatin 200 + 5 5.0 8.34 49.64 5.5
64.0~ 8889 Bentoriite 200~ Gelatin 200 + 10 3.0 10.40 70.50 2.5
66.0 9706 Bentonite 200~
CONCLUSIONS
[0069] 1) Electrospun fibrinogen (5 mg/ml) shortened FOT and R and
increased PCF at all fibrinogen concentrations tested. CEM and MA
increased in the electrospun material with the highest fibrinogen
concentration (Fibrinogen 150). [0070] 2) Gelatin 200 (5 mg/ml)
shortened FOT and R, did not alter PCF or MA and increased CEM.
[0071] 3) Gelatin 200+Bentonite 200 (5 mg/ml) had very little
effect on FOT and PCF and MA but increased CEM and shortened R.
[0072] 4) Gelatin 200+Bentonite 200 (10 mg/ml) shortened FOT and R
and increased PCF, CEM, and MA.
[0073] The overall results indicate that the combination of
bentonite and gelatin have as good or better ability to initiate
and form a strong clot as fibrinogen with the added advantage of
being much less expensive to produce. In addition, bentonite itself
produces higher PCF and ECM values at lower concentrations than
fibrinogen (also see Table 1). The TEG (FIG. 8C) also demonstrates
the favorable comparison of the gelatin/bentonite combination when
compared to fibrogen.
Part III.
Study Description
[0074] The specific aims of this study were to 1) Determine if
bentonite, gelatin and zeolite are capable of altering blood
clotting parameters and 2) Compare the clotting capabilities of
increasing concentrations of bentonite, gelatin and zeolite.
Results are given in FIGS. 9A and B (PCF and ECM), FIGS. 10A and B
(PCF and ECM), and FIGS. 11A-E (TEG).
CONCLUSIONS
[0075] In this study, the interactions of bentonite, zeolite, and
gelatin with whole blood were evaluated. The results indicate that
each one of these materials produces concentration dependent
shortening of the onset of clotting. The results also demonstrate
that shortening of the onset of clotting leads to enhanced clot
structural integrity. Overall, the results show that bentonite
rapidly produces a clot that is as strong or stronger than that
produced by zeolite, especially in terms of the CEM values. The low
cost of bentonite and its flexibility (in terms of its being made
into many farms that are suitable for application to sites of
hemorrhage) are additional significant advantages.
Example 3
Use of Bentonite Composition to Stanch Bleeding In Vivo
[0076] In an institutional review board approved study, two large
swine (50-80 kg) were used to test the ability of bentonite clay
granules to stop arterial bleeding. These experiments were modeled
after those of the U.S. Army Institute for Surgical Research in San
Antonio, Tex. The model is designed the test the ability of
hemostatic agents to control high pressure arterial bleeding (see
Acheson et al. Comparison of Hemorrhage Control Agents Applied to
Lethal Extremity Arterial Hemorrhage in Swine. J Trauma 2005:59;
865-875). After provision of proper anesthesia, the first animal
underwent surgical exposure of the left and right femoral artery
and the left carotid artery. A catheter was placed in the right
femoral artery for arterial blood pressure monitoring. A 6 mm
arteriotomy was created in the left femoral artery after lidocaine
was applied to the area to prevent arterial spasm. The animal was
allowed to hemorrhage for 30 seconds. At that time 3.5 ounces
(approximately 100 grams) of bentonite clay granules were poured
into the wound (this is approximately equivalent to the weight and
volume of Quick Clot as recommended by the manufacturer for use).
Pressure was then applied with simple gauze pad for 4 minutes.
After this time pressure was released. No further bleeding was
noted. The mean arterial blood pressure at the time of application
was 120 mmHg. The mean arterial blood pressure after the end of
application did not change. Using the same animal an arteriotomy
was made in the left carotid artery followed by immediate
application of the 3.5 ounces of bentonite clay. Pressure was
applied for 4 minutes. After this time pressure was released. No
additional hemorrhage was noted. The animal's blood pressure did
not change.
[0077] The second animal underwent similar experimentation except
that the left carotid artery was cannulated for monitoring of
arterial blood pressure. Both the left and right femoral arteries
were surgically isolated. Lidocaine was applied to the vessels to
prevent vasospasm. A 6 mm arteriotomy was made in the right femoral
artery. The animal was allowed to hemorrhage for 30 seconds. At
this time 3.5 ounces of bentonite clay was applied and pressure was
placed on the clay using simple medical gauze for 4 minutes. At
this time pressure was released and no further bleeding was
observed. The mean arterial blood pressure at this time was greater
than 80 mmHg. The experiment was repeated on the left femoral
artery with the same results. Complete control of hemorrhage was
obtained after application of 3.5 ounces of bentonite clay followed
by 4 minutes of pressure. Mean arterial blood pressure was again
greater than 80 mmHg. All animals were humanely euthanized after
the experiment. The above described testing is in some regards more
rigorous than the model created by the U.S. Army in that the mean
arterial blood pressures at the time of application were generally
higher which provides a further challenge in controlling hemorrhage
due to the hydrostatic forces within the arterial vasculature which
would tend to disrupt a formed clot after pressure is released from
the wound. It was noted in all cases that a hard cast was formed in
the wound cavity. This is due to the highly absorptive nature of
the bentonite clay. In the second animal, these casts were easily
removed from the wound allowing for complete visualization of the
femoral arteries. Neither artery had been transected. Removal of
the clay and clot directly over the vessel promoted rebleeding
demonstrating that the vessel was not irreparably damaged. The
ability to remove the cast should have medical and surgical
advantages at the time of vascular repair.
[0078] In the paper published by Acheson and colleagues (Acheson et
al. Comparison of Hemorrhage Control Agents Applied to Lethal
Extremity Arterial Hemorrhage in Swine. J Trauma 2005:59; 865-875)
all dressings and hemostatic strategies tested failed to prevent
death, except the fibrin sealant dressing which allowed for a 66%
survival rate. The use of the Hemcon Bandage, Army Field Dressing,
and Quick Clot did not produce any survivors in the experiment.
Using a different model of hemostasis Alam and colleagues (Alam, et
al. J Trauma 2003; 54:1077-1082) demonstrated the superiority of
Quick Clot when compared to the Hemocon Bandage, the Rapid
Deployment Hemostat Dressing, Trauma Dex, and a standard field
dressing. This model however is one of complete transection of the
femoral artery and vein, and animals are allowed to hemorrhage for
5 minutes. At this time arterial blood pressure is very low. Also,
after application of the hemostatic strategy, pressure is applied
to the wound for 5 minutes. Therefore, this model is not as severe
as the previously described Army model. This is further evidenced
by the fact that Quick Clot produced no survivors in the Army
study. In another study Alam et al (J Trauma 2004; 56:974-983)
using his previoius model described above, variations of Quickclot
were compared against the Hemocon bandage, Trauma Dex, Fast Act
(bovine clotting factor), and Quick Relief (a superabsorbent
polymer with potassium salt). The variations of Quickclot were
partially hydrated in an attempt to reduce the thermogenic reaction
produced by Quickclot. In this study only the original Quick Clot
product prevented any mortality. All other products produce
mortality rates ranging from 28% to 83%. This data indicates that
the thermogenic reaction of Quick Clot is likely to be most
responsible for its hemostatic actions. The combined data from the
above studies would indicate that the bentonite clay strategy
described in this application may provide a superior method of
hemostasis especially when cost of production, storage, and form
variation (granules, bandage, etc) are taken into account.
[0079] While the invention has been described in terms of its
preferred embodiments, those skilled in the art will recognize that
the invention can be practiced with modification within the spirit
and scope of the appended claims. Accordingly, the present
invention should not be limited to the embodiments as described
above, but should further include all modifications and equivalents
thereof within the spirit and scope of the description provided
herein.
* * * * *