U.S. patent application number 11/264584 was filed with the patent office on 2010-09-16 for process of making flowable hemostatic compositions and devices containing such compositions.
Invention is credited to Jonathan B. Gabel, Michael E. Guglielmo, Dwayne L. Looney.
Application Number | 20100230845 11/264584 |
Document ID | / |
Family ID | 37995217 |
Filed Date | 2010-09-16 |
United States Patent
Application |
20100230845 |
Kind Code |
A9 |
Gabel; Jonathan B. ; et
al. |
September 16, 2010 |
Process of making flowable hemostatic compositions and devices
containing such compositions
Abstract
The present invention is directed to processes of making
flowable hemostatic compositions and devices that include the
flowable hemostatic composition disposed therein, where a volume of
a biocompatible liquid, a volume of a biocompatible gas, and an
amount of solid particles of a biocompatible polymer are mixed
together to form a substantially homogenous composition including a
discontinuous gas phase and the solid particles substantially
homogenously dispersed throughout a continuous liquid phase to form
a flowable hemostatic composition, and the composition then
transferred into a device suitable for applying the flowable
hemostatic composition to a site of a body requiring hemostasis
under conditions effective to maintain the substantially
homogeneous dispersion of the gas phase and the solid particles
throughout the liquid phase, wherein said transfer of said
substantially homogenous hemostatic composition is conducted at an
angle.
Inventors: |
Gabel; Jonathan B.;
(Randolph, NJ) ; Looney; Dwayne L.; (Flemington,
NJ) ; Guglielmo; Michael E.; (Aberdeen, NJ) |
Correspondence
Address: |
ROBERTS MLOTKOWSKI SAFRAN & COLE, P.C.;Intellectual Property Department
P.O. Box 10064
MCLEAN
VA
22102-8064
US
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20070096354 A1 |
May 3, 2007 |
|
|
Family ID: |
37995217 |
Appl. No.: |
11/264584 |
Filed: |
November 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10896454 |
Jul 21, 2004 |
|
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11264584 |
Nov 1, 2005 |
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Current U.S.
Class: |
264/109 ;
424/443 |
Current CPC
Class: |
A61K 9/0019 20130101;
A61K 9/12 20130101 |
Class at
Publication: |
264/109 ;
424/443 |
International
Class: |
B27N 3/00 20060101
B27N003/00; A61K 9/70 20060101 A61K009/70 |
Claims
1. A process for making a medical device suitable for applying a
flowable hemostatic composition to a site of a body requiring
hemostasis, comprising: introducing a volume of a biocompatible
liquid into a mixing vessel equipped with a means for mixing said
liquid, introducing a volume of a biocompatible gas into said
volume of liquid while said means for mixing is operating under
conditions effective to mix said liquid and said gas together to
form a foam comprising a discontinuous gas phase comprising said
gas dispersed in a continuous liquid phase comprising said liquid,
introducing into said foam an amount of solid particles of a
biocompatible polymer suitable for use in hemostasis and which is
substantially insoluble in said liquid; and mixing said foam and
said solid particles together under conditions effective to form a
substantially homogenous composition comprising said discontinuous
gas phase and said particles substantially homogenously dispersed
throughout said continuous liquid phase, wherein the ratio of said
volume of liquid, said volume of gas and said amount of solid
particles is effective to provide said substantially homogeneous
composition with hemostatic properties, thereby forming said
flowable hemostatic composition; and transferring said hemostatic
composition into a device suitable for applying said hemostatic
composition to said site requiring hemostasis under conditions
effective to maintain the substantially homogeneous dispersion of
said gas phase and said solid particles throughout said liquid
phase, wherein said transfer of said substantially homogenous
hemostatic composition is conducted at an angle.
2. The process of claim 1, wherein said angle is about 3 to 10
degrees.
3. The process of claim 1, wherein said angle is about 4 to 7
degrees.
4. The process of claim 1, wherein said angle is about 5 to 6
degrees.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The subject matter of this application is related to U.S.
application Ser. No. 10/896647 filed Jul. 22, 2004, U.S.
application Ser. No. 10/896454 filed Jul. 22, 2004, U.S.
application Ser. No. 10/768335 filed Jan. 30, 2004 and U.S.
Provisional Application Ser. No. 60/493116 filed Aug. 7, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates to methods of making flowable
hemostatic compositions and devices containing such
compositions.
BACKGROUND OF THE INVENTION
[0003] Gelatin-based hemostats, both in solid sponge or powder
form, are commercially available and are used in surgical
procedures. Gelatin powder, when mixed with fluid, can form a paste
or slurry that is useful as a flowable, extrudable and injectable
hemostat for diffuse bleeding, particularly from uneven surfaces or
hard to reach areas. The conventional slurry is prepared at the
point of use by mechanical agitation and mixing of the powder and
liquid to provide uniformity of the composition. The paste then is
placed into a delivery means or applicator, e.g. a syringe, and
applied to the wound.
[0004] The main disadvantage of this approach is the need to mix
the powder with the liquid, knead it into a paste and back-fill it
into the delivery device of choice, all at the time of need and at
the point of use. The manipulations are time consuming and
potentially may compromise the sterility of the delivered product
depending on the environment of use. Thus, a need exists for a
sterile, flowable, hemostatic composition that is ready to use at
the point of use or can be prepared with minimal manipulation and
without risk of compromising the sterility of the product.
[0005] It would be desirable if a hemostatic device, e.g. a
delivery means such as a syringe or other applicator, would be
pre-filled with a hemostatic composition and available to the
surgeon at the point of use without need for further manipulation
or with minimal manipulation or preparation. The hemostatic
composition pre-filled in the device or applicator should be
sterile and flowable and should require minimum preparation time
and minimal force when extruded or injected through the delivery
means at the point of use. It also would be desirable to devise
processes for making such compositions that are commercially
viable, maintain an acceptable environment in the work place and
provide a pre-filled device comprising a hemostatic composition
that is flowable and physically stable. The present invention
provides such processes.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to processes of making
flowable hemostatic compositions and devices that are suitable for
use in applying such flowable hemostatic compositions and that
comprise the flowable hemostatic composition disposed therein. In a
process for making the flowable hemostatic composition, a first
volume of a biocompatible liquid is introduced into a mixing vessel
equipped with a means for mixing the liquid. A second volume of a
biocompatible gas is introduced into the volume of liquid while the
means for mixing is operating under conditions effective to mix the
liquid and the gas together to form a foam. The foam comprises a
discontinuous gas phase comprising the gas dispersed throughout a
continuous liquid phase comprising the liquid. An amount of solid
particles of a biocompatible polymer suitable for use in hemostasis
and which is substantially insoluble in the liquid is introduced
into the foam and the foam and the solid particles are mixed
together under conditions effective to form a substantially
homogenous composition comprising the discontinuous gas phase and
the solid particles substantially homogenously dispersed throughout
the continuous liquid phase. The ratio of the volume of liquid,
volume of gas and amount of solid particles is effective to provide
the hemostatic composition with hemostatic properties, thus forming
the flowable hemostatic composition. The flowable hemostatic
composition so formed is then transferred into a device suitable
for applying the flowable hemostatic composition to a site of a
body requiring hemostasis under conditions effective to maintain
the substantially homogeneous dispersion of the gas phase and the
solid particles throughout the liquid phase, wherein said transfer
of said substantially homogenous hemostatic composition is
conducted at an angle. The device comprising the flowable
hemostatic composition disposed therein is subjected, or exposed,
to conditions effective to provide a sterile device comprising a
sterile, flowable hemostatic composition. Compositions and devices
made by the processes of the present invention may be prepared well
in advance of the time of use and need not be prepared at the point
of use, yet they maintain physical properties effective to provide
flowability, extrudability or injectability at the point and time
of use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic cross-sectional side view of a mixing
apparatus used in processes of the present invention.
[0008] FIG. 2 is a schematic cross-sectional side view of a filling
apparatus used in processes of the present invention.
[0009] FIG. 3 is a side perspective view of an auger screw of the
type used in processes of the present invention.
[0010] FIG. 4a is a side elevation view of an apparatus used in
processes of the present invention.
[0011] FIG. 4b is a cross-sectional side view of an apparatus used
in processes of the present invention.
[0012] FIG. 5 is a side elevation view of an apparatus used in
processes of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Both sterilized and unsterilized compositions made by
processes of the present invention contain solid, porous or
non-porous particles of a biocompatible polymer suitable for use in
hemostasis, a biocompatible liquid and a biocompatible gas as its
three necessary components. The particles, liquid and gas are
combined and mixed under conditions effective to provide a
substantially homogeneous hemostatic composition comprising a
continuous liquid phase comprising the liquid, and the solid
polymer particles and a discontinuous gas phase comprising the gas
homogenously dispersed through the continuous liquid phase. The
amount and average diameter of particles contained in the
composition and the relative amount of the solid, liquid and
gaseous phases is effective to provide the composition with
hemostatic and physical properties, as described herein below.
[0014] The hemostatic composition so formed is a hemostatic paste,
or slurry, that exhibits improved properties of flowability,
extrudability and/or injectability when compared to flowable
hemostatic compositions of similar liquid/particle composition but
that do not contain a gaseous phase dispersed therethrough.
Compositions made by the processes of the present invention may be
prepared, filled into a medical device, such as a syringe or other
known applicators used to dispense flowable hemostatic
compositions, and sterilized by ionizing irradiation, well in
advance of the time of their intended use. The compositions further
may include additives to facilitate the preparation of the
composition, enhance physical and mechanical properties, enhance
the hemostatic properties of the composition, or provide
antimicrobial properties.
[0015] As used herein, "continuous" and "discontinuous" are used in
the ordinary meaning of those words in the context of standard
nomenclature used to define and describe dispersions. For example,
when combined and mixed with the continuous liquid phase, the
volume of biocompatible gas added to the liquid phase is disrupted
by mixing so as to form the discontinuous, i.e. dispersed, gaseous
phase comprising pockets or isolated bodies of gas.
[0016] As used herein, "substantially homogenous" denotes that
physical state of the compositions or pastes where the solid and/or
gaseous phases are uniformly dispersed throughout the continuous
liquid phase such that the ratio of solid:gas:liquid and the
density of any portion or cross-section of the composition or paste
are substantially the same.
[0017] As used herein, "foam" denotes that state where the
discontinuous gas phase has been dispersed in the continuous liquid
phase. The gas phase in the foam need not be substantially
homogenously dispersed through the foam.
[0018] As used herein, "density" is used in the ordinary meaning of
the word in the context of standard nomenclature used to define and
describe the mass of the mixture of the solids and the added liquid
per unit volume of the foamed paste.
[0019] As used herein, "sterile" means substantially free of living
germs and/or microorganisms and as further recognized and described
by governmental standards pertaining to compositions and medical
devices described and claimed herein. As used herein, "hemostatic",
or "hemostatic properties", means the ability to stop or minimize
bleeding, as one skilled in the art of hemostasis would understand
those terms to mean, as further exemplified in the examples of the
specification.
[0020] As used herein, "peak expression force" is the peak force
value required to extrude compositions from a pre-filled luer
syringe fitted with a 14 gauge angiocatheter tip, as described in
the examples of the specification.
[0021] A variety of biocompatible natural, semi-synthetic or
synthetic polymers may be used to prepare the solid particles used
in compositions of the present invention. The polymer selected must
be substantially insoluble in the liquid chosen for the particular
composition. Preferably, water-insoluble biodegradable polymers
that provide mechanical, chemical and/or biological hemostatic
activity are used. Polymers that may be used include, without
limitation, proteins and polysaccharides. Polysaccharides that may
be used include oxidized cellulose, chitosan, chitin, alginate,
oxidized alginate and oxidized starch. The biocompatible polymer
used to prepare the particles preferably is a cross-linked or
denatured protein, such as gelatin, collagen, fibrinogen or
fibronectin. A preferred gelatin powder is a partially cross-linked
gelatin powder prepared by milling gelatin sponge into particles
having an average diameter of from about 40 microns to about 1200
microns, or from about 100 microns to about 1,000 microns, as
determined by laser diffraction.
[0022] Compositions made by processes of the present invention
comprise a continuous liquid phase in which the solid particles and
gaseous phase are substantially homogenously dispersed. Depending
upon the particular medical device and use thereof, the liquid may
be aqueous or non-aqueous. In certain embodiments, the liquid phase
is aqueous. Aqueous liquids may include, without limitation,
biocompatible aqueous solutions, such as calcium chloride and
saline. More preferably, the liquid phase comprises saline. The
liquid phase and solid particulate phase are present in relative
amounts effective to provide a paste, or slurry, suitable for use
in providing hemostasis. Excessive dilution of the solid
particulate phase, although beneficial to further reduce the peak
expression force, will detrimentally affect the hemostatic
properties of the material and therefore is not desired. The weight
ratio of solid particles to liquid generally is from about 1:2 to
about 1:12. In certain embodiments the weight ratio of solid
gelatin particles to saline is from about 1:3 to about 1:6. In yet
other embodiments the weight ratio of solid gelatin particles to
saline is about 1:5.
[0023] Any biocompatible gas may be used to prepare compositions of
the present invention, including, but not limited to, air, carbon
dioxide, nitrogen, xenon or argon. Preferably an inert gas such as
argon or nitrogen is used. Air, nitrogen and argon are sensitive to
ultrasound and may provide a means to locate the composition once
injected in the body. Similarly, as xenon is radio-opaque, using
xenon also may provide a means to locate the composition once
placed in the body. In addition, as carbon dioxide lowers pH,
selection of carbon dioxide may enhance antimicrobial properties of
the compositions. The gas is combined and mixed with the continuous
liquid phase until it is dispersed throughout the liquid phase so
as to form a discontinuous gaseous phase dispersed in the
continuous liquid phase so as to form a foam. Upon formation of the
composition by dispersion of the particles in the foam, the
dispersion of the gas phase in the composition provides the
composition with improved physical properties relating to
flowability, extrudability and injectability, as described herein.
Such improved properties are characterized by way of physical
measurements of the compositions, including density and peak
expression force, both prior to and after irradiation of the
compositions during sterilization.
[0024] The relative concentration of the three major components of
the compositions of the present invention and the substantially
homogenous nature of such compositions are key in providing both
hemostatic and physical properties to the compositions. The solid
particles, liquid phase and gaseous phase generally will be present
in compositions made by processes of the present invention at a
ratio of from about 1:2:1 to about 1:12:13, based on
weight:volume:volume (g:ml:ml). In other embodiments the ratio will
be from about 1:4:1 to about 1:8:9. In yet other embodiments the
ratio will be about 1:5:3. The density of compositions of the
present invention will be from about 0.9 g/ml to about 0.3 g/ml, or
in certain embodiments from about 0.8 g/ml to about 0.6 g/ml.
[0025] Certain compositions made by the processes of the present
invention described herein are sterile, in that they have been
irradiated with a level of, e.g. ionizing irradiation. Such
irradiation may include e-beam or gamma irradiation. The level of
irradiation and conditions of sterilization, including the time
that the compositions are irradiated, are those that provide
sterile compositions, as defined herein. Once having the benefit of
this disclosure, one skilled in the art will be able to readily
determine the level of irradiation necessary to provide sterile
compositions.
[0026] The hemostatic compositions may further comprise effective
amounts of one or more additives or compounds including, but not
limited to, radio opaque agent, antimicrobial agents, foaming
agents, foam stabilizers, surfactants, antioxidants, humectants,
wetting agents, lubricants, thickeners, diluents, irradiation
stabilizers, e.g. radical scavengers, plasticizers, and
stabilizers. For example, glycerol may be added to enhance the
extrudability or injectability of the composition. Glycerol may be
present in the compositions up to about 20% by weight, or from
about 1% to about 10%, or from about 1% to about 5%, based on the
weight of the liquid phase. In addition, quaternary amines may be
used to provide enhanced properties to the compositions. For
example, benzalkonium chloride, Polybrene or Onamer M may be used
at levels up to about 1 percent by weight, based on the weight of
the liquid phase. In certain embodiments benzalkonium chloride is
used at levels of from about 0.001% to about 0.01%, or from about
0.002 to about 0.006% by weight, based on the weight of the liquid
phase. It is believed that the quaternary amines may serve multiple
functions, acting as an antimicrobial agent, a foaming agent, a
radical scavenger and/or as a heparin neutralizer.
[0027] Such hemostatic compositions may further comprise effective
amounts of heparin neutralizers, procoagulants or hemostatic
agents, such as thrombin, fibrinogen, fibrin, Factor Xa, or Factor
VIIa. By "effective amount", it is meant that amount necessary to
provide to the compositions those properties for which the additive
is being added. The maximum amount that may be added is limited so
as not to cause detrimental biological affects.
[0028] Compositions made by processes of the present invention are
particularly advantageous for use in hemostatic compositions where
additives that are sensitive to irradiation, are utilized. For
example, thrombin, in an aqueous solution, has been found to lose
all procoagulant activity when exposed to sterilization
irradiation. In contrast, thrombin retained approximately 40% of
its original enzymatic activity and all of its hemostatic activity
after sterilization when formulated in compositions according to
this invention, as shown in Example 9. While bovine thrombin is
exemplified herein, human-derived thrombin such as described in
U.S. Pat. No. 5,143,838, the content of which is hereby
incorporated by reference herein in its entirety, also may be used
in compositions of the present invention.
[0029] Medical devices in which the hemostatic compositions of the
present invention may be utilized include any device currently
being used to apply a flowable or injectable hemostatic paste or
slurry to a site, or wound, requiring hemostasis. The site
requiring hemostasis may be the result of an injury or a surgical
procedure. Examples of devices or applicators include syringes such
as Becton Dickinson or Monoject luer syringes. Other devices are
disclosed in detail in U.S. Pat. No. 6,045,570, the contents of
which are incorporated by reference in their entirety.
[0030] In processes of the present invention, the liquid is added
to the mixer. The gas then is incorporated into the liquid with
mixing under conditions effective to form a foam comprising a
discontinuous gas phase of the gas dispersed through a continuous
liquid phase of the liquid. In certain embodiments the gas and
liquid may be mixed for from about 3 to about 30 minutes. The solid
polymer particles are then incorporated into the foam and mixed so
as to substantially homogenously disperse the solid particles
throughout the foam. In certain embodiments the foam and particles
may be mixed for from about 15 to about 30 minutes, although mixing
for more than 30 minutes is acceptable. In such embodiments a
mixer, e.g. a double planetary mixer, may be utilized.
[0031] The liquid may include effective amounts of additives
dissolved therein prior to addition of particles or the gas to the
solution. For example, a saline solution containing glycerol and
benzalkonium chloride may be prepared and then added to the mixer.
A source of gas is provided to the mixer whereby a first portion of
the gas may be added to the liquid solution. The mixture of gas and
liquid is mixed to disperse the gas in the liquid phase, thus
forming a foam. The solid particles and any additional portion of
gas then are added to the mixer over time with continuous mixing
until all ingredients have been added. The mixing is continued
until such time as a substantially homogenous composition is formed
containing the solid particles and discontinuous gaseous phase
uniformly dispersed throughout the continuous liquid phase. The
density of the mixture of liquid, gas and solid particles may be
monitored to determined at what point the composition is
substantially homogeneous so as to provide the composition with
desired physical and hemostatic properties.
[0032] The flowable hemostatic compositions so formed are then
transferred into a device suitable for applying the flowable
compositions to a site of the body requiring hemostasis. The filled
device and composition contained therein then are sterilized to
provide a sterile, ready-to-use system that avoids issues of the
current state of the art with regards to on-site preparation and
handling just prior to use.
[0033] While preparation of compositions and devices noted above
may be readily achieved on a small scale, such as a laboratory
setting, the preparation of such compositions and devices on a
scale suitable for commercial use presents additional issues.
[0034] In a commercial manufacturing setting, certain issues not
readily apparent in the small scale preparation of compositions and
devices must be addressed, including the general environment of the
workplace, potential increased bioburden of the solid particles due
to exposure to the atmosphere, and maintaining the physical
structure and properties of the compositions during transfer to the
applicator devices and sterilization. For example, when a large
quantity of fine particles in the form of a powder are added to a
mixing vessel, the fine particle size of the particles in the
powder may cause excessive dusting in the workplace, which may
create environmental concerns, including issues related to
personnel safety and general maintenance of the workplace, as well
as the qualification grade of the facility. Additionally, gelatin
based materials, for example, when exposed to the environment for a
prolonged period of time, may be subject to infestation by
microorganisms. The increased bioburden of the powder may lead to
degradation of the gelatin during processing and may be detrimental
to the sterility and biocompatibility of the product.
[0035] In order to minimize the environmental issues that may be
caused by excessive dusting, one solution may be to compact or
condense the particles into a physical body, such as pellets,
granules or any other appropriate shape prior to the mixing. The
body of particles may, but need not, comprise a plurality of packed
particles comprising interstitial pores having a pore volume and a
median pore diameter effective to provide improved absorption of an
aqueous media into the interstitial pores when placed in contact
therewith, compared to a plurality of unpacked particles.
[0036] Alternately, the solid particles may be added to the mixing
vessel containing the foam through a structure or conduit that is
closed or sealed so as to avoid exposure of the powder particles to
the atmosphere during addition. Adding the particles via such a
structure minimizes dusting caused by the addition of fine
particles, as well as reduces the opportunity for the growth of
microorganisms on the residual particles previously trapped on the
inner wall of the mixing vessel prior to incorporation.
[0037] In addition to environmental issues as discussed above,
transfer of the flowable hemostatic compositions from the mixing
vessel to the medical devices may lead to the breakdown or
deformation of the physical structure of the composition, i.e.
disruption of the dispersion of the solid particles and gas phase
throughout the liquid phase. If one were to attempt to transfer the
substantially homogenous hemostatic composition from the mixing
vessel to the applicator device by relatively high pressure, it may
be difficult to maintain the structure of the hemostatic
composition due to compression forces that may arise due to the
relatively high pressure required to move the paste in such
instances. Such compression could lead to separation of the gaseous
phase from the liquid phase. Such a loss of the gaseous phase is
detrimental to the mechanical properties of the composition, e.g.
flowability and ease of mixing, both during and after the
irradiation process.
[0038] The processes of the present invention minimize such
detrimental effects by transferring the composition throughout the
process under conditions that avoid the creation or presence of
appreciable pressures that may lead to compression forces.
Preferably, the composition is transferred from the mixing vessel
into the applicator device in the substantial absence of such
compression forces and under minimal pressure conditions, meaning
those conditions that provide for efficient transfer of the
composition without detrimentally affecting the structure of the
composition.
[0039] In order to maintain minimal pressure conditions, certain
embodiments of processes of the present invention utilize an auger
screw to transfer the hemostatic composition into the applicator
device. In certain embodiments exemplified herein, the auger screw
is used in a vertical orientation to take advantage of
gravitational forces for filling the devices, although it is
contemplated that transfer of the composition from the mixing
vessel to a filling apparatus could be conducted with a horizontal
screw orientation. The auger screw provides for local movement of
the compositions through the process versus bulk transfer. In this
way, large forces applied to the bulk of the composition that may
lead to compression on the whole of the body of material may be
avoided in lieu of localized forces within the body of
material.
[0040] As the compositions prepared according to the present
invention comprise gaseous, liquid and solid phases, as described
above, maintaining the structure of the composition will depend in
part on the design of the auger screw. To maintain the structure
and ratios of liquid:gas:solid particles of the compositions within
acceptable parameters, and thus the density of the extruded
hemostatic paste within an acceptable density range, considerations
for an auger design include the width, number and pitch of the
flights on the auger screw, the angle of the flight to the auger
screw rod, the design and finish of the auger bowl, the diameter
and angle of the agitator blade and on the overall scale of the
apparatus.
[0041] Once transferred into the holding vessel of the filling
apparatus, maintaining conditions effective to maintain the
structure of the compositions during filling will depend on a
number of aspects. One consideration is the amount of work that may
be imparted to the compositions either by the auger screw or by
gravitational forces exerted on the bulk of the composition. The
resident time of the compositions within the filling apparatus is
related to each of these considerations. The longer the composition
is held within the filling apparatus, the longer it is subjected to
repetitive, pulsing forces created by the auger screw during
filling and the longer it has to have the weight of the body of the
composition act to compress the composition itself, each of which
may lead to separation of the gas phase from the liquid phase. In
addition, the configuration and finish of the auger bowl must be
considered. Surface finishes that minimize friction between the
material and the sides of the auger bowl will minimize any
detrimental effects that may be caused by friction.
[0042] It was found that the resident time of the compositions in
the filling apparatus, the overall work imparted to the
compositions and the rate of transferring the compositions into the
applicator device may be optimized such that the adverse effects,
as stated above, may be minimized. With respect to specific
embodiments exemplified herein, it was found that the rate of
transfer of the composition from the holding vessel of the
apparatus to the devices advantageously is at least about 12
ml/minute, or at least about 36 ml/minute, or even about 72
ml/minute, and even more than about 100 ml/minute. It will be
understood by those skilled in the art that the actual rate at
which the composition is transferred in order to optimize resident
time work imparted to the composition, however, will depend upon
the particular design and size of the filling apparatus, as well as
the particular composition being filled.
[0043] As shown in FIG. 1, mixing apparatus 10 includes mixing
vessel 12, equipped with mixing means 14. Mixing means 14 comprises
multiple helical blades 16 that rotate on their own axes, while
orbiting mixing vessel 12 on a common axis. Helical blades 16
continuously advance around the periphery of mixing vessel 12,
removing material from internal mixing vessel wall 18 and
transporting to the interior of mixing vessel 12, thus allowing the
entire batch of materials to be mixed thoroughly. Mixing vessel 12
is fit with mixing vessel cover 36 so as to provide a closed
system. Mixing cover 36 includes addition ports 24, 30 and 34 for
addition of liquid 22, gas 40 and solid particles 26 into mixing
vessel 12. Hopper 28 containing solid particles 26 is in a closed
relationship with mixing vessel cover 36 via conduit 32 including
powder flow regulating valve 38 to minimize exposure of solid
particles 26 from the atmosphere.
[0044] In one embodiment of the process, liquid 22 is added to
mixing vessel 12 via port 24. Mixing means 14 is engaged at a rate
of from about 60 to about 80 Hz to facilitate mixing of gas 40 and
liquid 22 when the two are placed together. Gas 40 is introduced
into liquid 22 in mixing vessel 12 via port 34. Liquid 22 and gas
40 are mixed at a rate and for a time effective to provide a foam
as described herein above. Solid particles 26 are then introduced
into the foam via conduit 32. The foam and solid particles 26 are
then mixed at a rate and for a time effective to substantially
homogenously disperse particles 26 throughout the foam. Once
prepared, the flowable hemostatic composition is transferred to a
holding vessel of a filling apparatus shown in FIG. 2 for
subsequent filling into an applicator device. The transfer of the
hemostatic composition to the holding vessel may be conducted
manually, e.g., by using a sterile scoop, as described herein, or
by any automated means.
[0045] As shown in FIG. 2, filling apparatus 40 includes holding
vessel 42 for holding flowable hemostatic composition 44 and auger
screw 46 disposed within holding vessel 42 and auger funnel 48 and
in cooperation with motor 54 and agitator blade 49 in cooperation
with motor 47. Auger screw 46 transports flowable hemostatic
composition 44 from holding vessel 42 and through auger funnel 48
in a downward spiral fashion. Agitator blade 49 serves to prevent
material from building on the walls of the holding vessel while
also maintaining the homogenous structure of the composition during
filling. Flowable hemostatic composition 44 then is transferred
into applicator device 52 via exit port 50. As composition 44 is
filled into devices 52, 56, 58, auger screw 46 is in operation to
affect transfer. After device 50 is filled, operation of auger
screw 46 is disrupted and the stream of the composition separated
to provide for subsequent filling of additional devices 56 and 58.
The repeated disruption of flow creates a pulsating force upon
composition 44 within holding vessel 42. This repeated mechanical
manipulation of the composition may detrimentally affect the
composition properties. Thus, as discussed above, the design of
auger screw 46 and the rate of filling devices 52, 56 and 58 are
optimized to minimize negative effects.
[0046] An auger screw of the type that may be used in processes of
the present invention is shown in FIG. 3. As shown, screw 60
comprises multiple flights 62, 64 attached to auger screw rod 66.
As shown, flight 62 has a greater diameter than flight 64. In
embodiments of the present invention, the number, diameter, angle
and distance between fights may be designed to accommodate
particular apparatus being used or the composition itself. One
skilled in the art will be able to readily ascertain other screw
designs that may be employed in processes of the present invention
once having the benefit of this disclosure.
[0047] The auger screw transfers the composition from the holding
vessel into the applicator devices. FIGS. 4a and 4b depict a
typical fixture that may be used to hold applicator devices such a
syringes during the filling process. Fixture 70, i.e. the syringe
loading station, is equipped with syringe holder 72 having multiple
syringe receptacles 74, and means for securing the syringes to
fixture 70 that includes clamping screw 76, clamping rod 78, and
syringe impingement pin 80. Syringe 82 is placed within syringe
receptacle 74. Each syringe is back-filled with the same volume of
paste in a sequential manner using the apparatus described above.
The back-filling operation involves dispensing the composition into
syringe 82 from the back end of syringe 82. Syringe 82 is held in
place by clamping screw 76. Upon completion of filling, Syringe
impingement pin 80 contacts the external of syringe 82, thus
creating pressure on syringe 82 that results in the separation of
the stream of composition between syringe 82 and the port of the
filling apparatus. Fixture 70 then indexes such that next syringe
82 is moved to be in a filling position. Once filled, the syringe
plunger is inserted into the back end of the filled syringe and
advanced to its appropriate position, followed by capping of
syringe 82.
[0048] In one embodiment, the basic design of the means for
transfer of the material into the device, including securing the
syringe, use of the impingement pin to affect separation of the
material stream, indexing the multiple syringes in a vertical
motion followed by horizontal motion may be automated. For example
a circular fixture comprising multiple receptacles may index in a
circular manner to provide filling of the device.
[0049] In another embodiment, one may mechanically or pneumatically
cut the paste at the auger orifice tip using a rotating wire or air
blade to separate the paste from the auger.
[0050] Yet in another embodiment, one may place a wire or blade
across the diameter of the auger dispenser orifice causes an
increase in the effective diameter of the paste, resulting in the
extruding of two mirror image "D" shape slugs to split and deflect
the paste, enabling the slugs to have good surface contact with the
syringe internal diameter with less or no indent.
[0051] Yet in another embodiment, one may deflect the paste
sideways to make contact with the syringe barrel wall with an
angled or curved auger orifice tip. In this embodiment, geometrical
constraints limit the amount of deflection possible without
reducing the effective cross sectional area of the orifice tip
which requires additional protrusion of the orifice tip into the
syringe.
[0052] Preferably, the paste and/or the receptacle is positioned at
angle in order to allow the paste to make contact with the
receptacle side wall and subsequently, the paste will be separated
cleanly. The "angle", (i.e. alpha), as used herein, refers to the
angle between the long axis of the syringe and the long axis of the
auger. FIG. 5 depicts such a fixture that may be used to hold
applicator devices such as a syringe during the filling process.
The angle from the auger tip is at an angle of 3-10 degrees, with a
preferred range of 4-7 degrees with the most preferred being 5-6
degrees. Alternatively, this can also be accomplished by tilting
the auger equipment, with the syringe held vertical or by tilting
the syringe with the auger in a vertical position. The latter
requires additional protrusion of the orifice tip into the syringe
by a small amount.
[0053] In employing this method, the paste slug comes into contact
with the syringe barrel wall immediately upon exiting and as it is
extruded from the auger dispenser orifice. This method results in
more surface area of the paste in contact with the syringe barrel
wall than in the current method. The paste slug "bulges" at the
initial point of wall contact such that it is in contact with the
syringe barrel wall all around its cylindrical surface. This also
results in a smaller cross sectional area of the paste at the auger
tip orifice than the paste that is distal to the auger tip orifice,
which results in a cleaner and more consistent breaking location
for the paste.
[0054] This more readily automated angled approach involves less
process steps, offering a faster, consistent delivery of the past
into the syringe.
[0055] One skilled in the art may envision other means for
manufacturing such compositions and filling them into devices. For
example, a pump technique can be used whereby powder can be added
to a re-circulating loop of foaming solution. The foaming solution
may be pumped utilizing a low-shearing pump and the powder can be
added until the desired properties have been achieved. Once the
desired ratio of liquid to solid is reached, the gas will be
introduced into the re-circulating paste. A chamber can be included
to allow for the expansion of the paste. When the chamber is full,
such that the desired density is reached, the foamed paste can be
continuously filled into syringes.
[0056] Given that the density of the flowable hemostatic
composition is an indicator of acceptable mechanical and hemostatic
properties of the compositions, the density of the flowable
hemostatic composition is measured upon completion of mixing to
ensure acceptable properties. One method of assessing the density
used and described herein includes suspending the hemostatic
composition in a series of organic solvents of known densities or
measuring the weight of a known volume of the composition, although
other methods of measuring density could be utilized. In monitoring
the density of compositions in processes of the present invention,
the density of the flowable hemostatic composition is assessed by
using inert organic liquids with known densities. The liquids are
selected such that any possible interactions with the compositions
will have no impact on the measurements. The choice of the solvent
density coincides with the predetermined acceptable density range
of the hemostatic composition. The composition is placed in a
series of solvents of varying densities and the density of the
composition determined based on whether it sinks or floats in the
solvent.
[0057] The hemostatic compositions prepared as above are
transferred into a medical device as described above and the device
containing the hemostatic composition is sterilized, preferably by
ionizing radiation. More preferably, sterilization is by gamma
irradiation as exemplified herein.
[0058] While the following examples demonstrate certain embodiments
of the invention, they are not to be interpreted as limiting the
scope of the invention, but 10 rather as contributing to a complete
description of the invention.
EXAMPLES
[0059] Samples prepared in the examples below were tested for peak
expression force as determined using a Chatillon TCD 200, using a
50-lb load cell [DFG 550] at 15 a speed of 2 inches/minute. An
in-dwelling catheter sheath (size 12-14 gauge) was attached to the
sample syringe to be tested. The syringe then was inserted into a
holding apparatus, which then was loaded onto the test instrument.
The peak expression force was noted.
Example 1
[0060] A total of ten samples were prepared as follows. One gram of
dry Surgifoam.RTM. powder was placed in a plastic container and
mixed with 4 ml of saline. The container was capped and the
contents were shaken until a substantially homogenous paste of
uniform consistency was obtained. The paste was formed into a
cylindrical shape and placed into a 10 cc BD polypropylene
disposable luer syringe. The syringes were then capped and five of
the filled syringes were sterilized by gamma irradiation at a dose
of 25 kGy. The Peak Expression Force was determined and presented
in Table 1. Unsterilized samples are designated as 1a and
sterilized samples are designated as 1b.
[0061] At total of 10 samples were prepared as follows. 1 gm of dry
Surgifoam.RTM. powder was placed in a plastic container and mixed
with 4 ml of saline. The container was capped and the contents were
shaken until a substantially homogenous paste of uniform
consistency was obtained. The paste was formed into a cylindrical
shape and placed into a 10 cc BD polypropylene disposable luer
syringe. A second 10 cc BD luer syringe containing 3 ml of nitrogen
then was connected to the syringe containing the paste such that
the paste could be passed from syringe to syringe. The paste and
gas were extruded back and forth between the syringes to thoroughly
mix and disperse the gas throughout the paste until a substantially
homogeneous foam-like composition of uniform consistency was
obtained. The syringes were then capped and five of the filled
syringes were sterilized by irradiation at a dose of 25 kGy. The
Peak Expression Force was determined and presented in Table 1.
Unsterilized samples are designated as 1a ' and sterilized samples
are designated as 1b'.
Example 2
[0062] A total of ten samples were prepared as follows. A saline
solution containing 0.005% by weight of benzalkonium chloride and
5% weight of glycerol was prepared. This solution was used to
prepare homogenous gelatin-powder pastes as described in Example 1.
The paste was formed into a cylindrical shape and placed into a 10
cc BD polypropylene disposable luer syringe. The syringes were then
capped and five of the filled syringes were sterilized by
irradiation at a dose of 25kGy. The Peak Expression Force was
determined and presented in Table 1. Unsterilized samples are
designated as 2a and sterilized samples are designated as 2b.
[0063] A total of ten samples were prepared as follows. A saline
solution containing 0.005% by weight of benzalkonium chloride and
5% by weight of glycerol was prepared. This solution was used to
prepare homogenous gelatin-powder pastes as described in Example 1.
A second 10 cc BD luer syringe containing 3 ml of nitrogen then was
connected to the syringe containing the paste such that the paste
could be passed from syringe to syringe. The paste and gas were
extruded back and forth between the syringes to thoroughly mix and
disperse the gas throughout the paste until a homogeneous foam-like
composition of uniform consistency was obtained. The syringes were
then capped and five of the filled syringes were sterilized by
irradiation at a dose of 25 kGy. The Peak Expression force was
determined and presented in Table 1. Unsterilized samples are
designated as sample 2a' and sterilized samples are designated as
2b'. TABLE-US-00001 TABLE 1 Peak Expression Force Samples pounds (n
= 5) Samples 1a 21.8 Samples 1b 26.4 Samples 1'a 12.0 Samples 1'b
21.0 Samples 2a 17.2 Samples 2b 22.4 Samples 2'a 11.8 Samples 2'b
16.8
[0064] As the data in Table 1 indicates, the inclusion of the
gaseous phase homogenously dispersed throughout the paste
significantly reduces the peak expression force of the composition
prior to sterilization compared to pastes that do not include the
homogenously dispersed gaseous phase or other additives.
Consequently, the sterilized composition including the homogenously
dispersed gaseous phase exhibits an expression force significantly
less than that of a sterilized paste that does not include the
homogenously dispersed gaseous phase. In fact, the sterilized
composition including the gas phase approximates the expression
force of the pre-sterilized paste containing no gaseous phase or
additives. Thus, a fully sterilized composition may be provided
with flowability and/or injectability, as evidenced by peak
expression force, equal to or better than that of an unsterilized
paste containing no gaseous phase or additives, which is beneficial
to health care providers at the point of use. The use of additives,
e.g. benzalkonium chloride and glycerol, may be used to further
enhance the properties of the compositions of the present invention
upon sterilization.
Example 3
[0065] 25 grams of Surgifoam.RTM. gelatin powder were mixed with
125 ml of normal saline containing 0.005% benzalkonium chloride and
5% glycerol, based on weight of saline, until a uniform paste was
formed. The resulting paste was loaded into a 1/2 pint Donvier
mixer fitted with a mixing paddle. A tube connected to a nitrogen
source was fitted through the lid of the mixer and the system
"closed" to the environment by wrapping in a film. The system was
purged with nitrogen for 20 minutes. The paste was then mixed to
homogenously incorporate the nitrogen by rotating the paddle
rapidly by hand. Mixing was terminated when the composition filled
the available volume, indicating homogeneous distribution of the
gas phase. The composition was loaded into a 60 cc syringe and
subsequently dispensed into 10 cc BD luer syringes via a two-way
luer connector. The density of the composition was approximately
0.7-0.75 grams/ml. The syringes were then capped and some of the
filled syringes were sterilized by irradiation at a dose of 25
kGy.
Example 4
[0066] 2.5 liters of normal saline containing 0.005% benzalkonium
chloride and 5% glycerol dissolved therein, based on the weight of
saline, were added to a 2-gallon double planetary Ross mixer and
mixed at maximum speed with a first portion of nitrogen for 5
minutes to form a foamed liquid. 500 grams of gelatin powder and
the balance of nitrogen were added to the foamed liquid over a
12-minute time period with continuous mixing. The composition was
mixed for a further 10 minutes after all of the powder and gas was
added. The density of the resulting composition was 0.6 grams/ml.
The composition was dispensed into 12 cc Monoject syringes.
Example 5
[0067] One-gram samples of Surgifoam.RTM. gelatin powder each were
mixed with 5 ml of a saline solution containing 0.005% benzalkonium
chloride and 5% glycerol to form uniform pastes. The resulting
paste was back-loaded into 10 cc BD luer syringes. All air was
extruded from the syringes, leaving the paste packed in the
syringe. The first set of syringes was irradiated with no gas
incorporated therein and designated as sample 5a. A second set of
samples was prepared by dispensing 3 ml of nitrogen into the
syringes containing the uniform paste. The syringes were capped
without further mixing and then stored at 4.degree. C. The samples
were designated as samples 5b. The third set of samples were
prepared by extruding the paste back and forth between the first
syringe and a second syringe containing 3 ml of nitrogen until all
of the nitrogen was homogenously incorporated into the paste. The
fill-volume of the resulting homogeneous compositions was
approximately 9 ml and the density of the composition was
approximately 0.7 grams/ml. The syringes were then capped and some
of the pre-filled syringes were sterilized by irradiation at a dose
of 25 kGy. The Peak Expression Force of the three sets of samples
was determined and presented in Table 2. TABLE-US-00002 TABLE 2
Peak Expression Force Samples pounds (n = 5) Samples 5a 21.7
Samples 5b 20.7 Samples 5c 15.5
[0068] As the data in Table 2 indicates, homogeneous
distribution/dispersion of the gas throughout the paste is
essential to reduce the peak expression force of the composition
prior to irradiation and to maintain the lower peak expression
force of the composition after irradiation, compared to pastes
containing no gas or having gas poorly or partially dispersed there
through.
Example 6
[0069] One gram of Surgifoam.RTM. gelatin powder was mixed with 5
ml of normal saline to form a uniform paste. The resulting paste
was back-loaded into a 10 cc BD luer syringe. All air was extruded
from the syringe leaving the paste packed in the syringe. A second
set of 10 cc syringes containing nitrogen with volume ranging from
1 ml to 4 ml, respectively, was fitted to the first via a two-way
luer connector. The paste was extruded into the gas and then passed
back and forth between the two syringes until all of the gas was
homogeneously incorporated into the paste. The fill-volume of the
resulting composition was approximately 6-10 ml and the density was
approximately 0.60 to 1.0 grams/ml, each depending on the volume of
gas introduced into the paste. The syringes were then capped and
some of the pre-filled syringes were sterilized by irradiation at a
dose of 25 kGy. Sterilized samples were noted as samples 6a through
6e, respectively. The Peak Expression Force of the sterilized
samples was determined and presented in Table 3. TABLE-US-00003
TABLE 3 Density (g/ml) Peak Expression Force Samples Gas Volume
(ml) (Pre-sterilized) pounds n = 5 Sample 6a 0 1.00 14.8 Sample 6b
1 0.86 12.9 Sample 6c 2 0.75 10.6 Sample 6d 3 0.66 8.6 Sample 6e 4
0.60 8.0
Example 7
[0070] One gram of Surgifoam gelatin powder was mixed with 5 ml of
normal saline to form a uniform paste. The resulting paste was
back-loaded into a 10 cc BD luer syringe. All air was extruded from
the syringe, leaving the paste packed in the syringe. A second set
of 10 cc syringes containing air with volume ranging from 0 ml to 4
ml, respectively, were fitted to the first syringe via a two-way
luer connector. The paste was extruded into the gas and then passed
back and forth between the two syringes until all of the gas was
homogenously incorporated into the paste. The fill-volume of the
resulting composition was approximately 6-10 ml and the density was
approximately 0.60 to 1.0 grams/ml, each depending on the volume of
gas introduced into the paste. The syringes were then capped and
some of the filled syringes were sterilized by irradiation at a
dose of 25 kGy. Sterilized samples were noted as samples 7a through
7e, respectively.
[0071] The Peak Expression Force of the sterilized samples was
determined and presented in Table 4. TABLE-US-00004 TABLE 4 Density
(g/ml) Peak Expression Force Samples Gas Volume (ml)
(Pre-sterilized) pounds n = 5 Sample 7a 0 1.00 14.8 Sample 7b 1
0.86 11.0 Sample 7c 2 0.75 10.9 Sample 7d 3 0.66 10.1 Sample 7e 4
0.60 10.0
Example 8
Hemostatic Performance of Different Materials in Porcine Splenic
Biopsy Punch Model
[0072] A porcine spleen biopsy punch model was used for evaluation
of the hemostatic properties of samples prepared in Examples 1
through 7 and 9. A 6-mm biopsy punch was used to cut a tissue flap
3 mm deep. The tissue flap was cut out and 0.4 ml of the test
materials was applied to the wound site. Manual compression was
held over the wound site for 2 minutes. The wound site was then
observed for up to 3 minutes for signs of bleeding. If bleeding was
observed, additional applications of manual compression for 30
seconds each time were used until complete hemostasis was achieved.
Table 5 lists the results of the evaluation. Results for
unsterilized or sterilized samples are represented as an average
values for all samples tested. TABLE-US-00005 TABLE 5 Time to
Hemostasis Samples Number of Compressions (min:sec) Samples 1a 3
3:35 (n = 2) Samples 2a 3 3:33 (n = 2) Samples 1b 1 2:00 (n = 3)
Samples 2b 2 3:00 (n = 6)
Example 9
[0073] Two vials of lyophilized Bovine thrombin (20,000 units
Thrombogen JJMI) were reconstituted in 20 ml of saline to provide a
working solution of 1000 u/ml. Clotting activity was measured in an
in vitro test as described in Example 10. One vial of this material
was stored at 4-8.degree. C. and the clotting activity measured at
day 1, day 8 and day 30, respectively. The second vial was
sterilized by gamma irradiation (25 kGy) and the clotting activity
measured as above. The unsterilized and sterilized samples were
designated samples 9a and 9b, respectively. Both sterilized and
unsterilized samples were stored at 4-8.degree. C. between
measurements.
[0074] Another 2 vials of 20,000 units of lyophilized bovine
thrombin were reconstituted in saline containing 0.005%
benzalkonium chloride and 5% glycerol. One vial was stored at.
4-8.degree. C. and the clotting activity was measured at day 0, day
1, day 8 and day 30. The second vial was sterilized by gamma
irradiation (25 kGy) and the clotting activity measured as above.
In between measurements both the sterilized and unsterilized
samples were stored at 4-8.degree. C. The unsterilized and
sterilized samples were designated samples 9c and 9d,
respectively.
[0075] Several samples of gelatin paste containing the thrombin
noted above were prepared by mixing 1 gram of Surgifoam gelatin
powder with 5 ml of thrombin solution. The resulting paste was
loaded into a 10 cc syringe. Samples were then either sterilized at
25 kGy followed by storage at 4-8.degree. C., or stored
unsterilized at 4-8.degree. C. Samples so prepared are designated
and identified below. [0076] Sample 9e=1 g Surgifoam.RTM. powder
plus 5 ml of sample 9a; Sterilized [0077] Sample 9f=1 g
Surgifoam.RTM. powder plus 5 ml of sample 9a plus 3 ml Nitrogen:
Foamed and Sterilized [0078] Sample 9g=1 g Surgifoam.RTM. powder
plus 5 ml of sample 9c; Unsterilized [0079] Sample 9h=1 g
Surgifoam.RTM. powder plus 5 ml of sample 9c; Sterilized [0080]
Sample 9i=1 g Surgifoam.RTM. powder plus 5 ml of sample 9c plus 3
ml Nitrogen; Foamed and Sterilized
Example 10
[0081] Measurement of Thrombin Activity by an In Vitro Coagulation
Test in a Fibrometer Instrument (BBL)
[0082] Serial dilutions of test sample containing thrombin were
prepared in Veronal buffer pH 7.2. 0.2 ml of pooled normal plasma
(Citrol Level I control plasma--Dade Diagnostics) was warmed to
37.degree. C. in the fibrometer incubator block. 0.1 ml of
pre-warmed sample dilution was added to the plasma and the timer
started simultaneously. The time to clot formation was recorded.
All samples were tested in duplicate and an average clotting time
calculated. Data was graphed as the log.sub.10 dilution vs.
log.sub.10 clotting time and a regression analysis performed.
Freshly prepared thrombin was considered to have 100% activity and
all other samples were calculated as a percentage of the activity
relative to the freshly prepared thrombin. Results are presented in
Table 6 and Table 7. TABLE-US-00006 TABLE 6 Effect of Storage time
on Thrombin Activity: Stabilization by Formulated Gelatin Paste
Storage Solution Percent Loss in Thrombin Activity (Stored at
6.degree. C.) Time 0 Day 1 Day 8 Day 30 9a 0 0 53.3 90.8 9c 0 NA
41.1 82.9 9g 0 0 0.8 0
[0083] TABLE-US-00007 TABLE 7 Effect of Gamma Irradiation on
Thrombin Activity: Stabilization by Formulated Gelatin paste Media
for Sterilized Thrombin * Samples % Loss in Thrombin Activity (5
ml/g gelatin powder- 25 kGy Dose) Day 6 Day 20 9b 100 100 9d 96.0
100 9e 72.6 NA 9f 66.8 56-72 9h 79.2 ND 9i 63.8 61-73
[0084] TABLE-US-00008 TABLE 8 In vivo Hemostasis Performance of
Pre-filled Thrombin/Gelatin Paste Number of Time to Hemostasis
TIME: Sample Compressions (min:sec) Day 0: 9 g 1 0:30 Day 42: 9 g 1
0:30 Day 42: 9 g 1 0:30 Day 42: 9 h 1 0:30 Day 42: 9 h 1 0:30
Example 11
[0085] One liter of a saline solution containing 0.005% by weight
of benzalkonium chloride and 5% weight of glycerol were poured into
a mixing vessel (Ross Mixer, Model DPM2, Serial #75308) and the
mixer blades engaged in an operating mode. Nitrogen gas was
introduced into the solution via a tube connected to a nitrogen
source in a continuous bubbling manner. The mixture of solution and
gas was stirred at 70 Hz for approximately 10 minutes in order to
form a foam as described herein above. The addition of the solid
particles was commenced after formation of the foam using an
addition-funnel attached to the entry port of the mixing vessel.
200 grams of gelatin powder were added over a time period of about
3 minutes. The mixing was continued for about 15 minutes after
total powder addition at 70 Hz, followed by additional mixing for
about 2 minutes at a reduced blade speed of about 12 Hz. Upon
completion of the mixing, the density of the composition in the
mixing vessel was measured using the solvent method as described
above to ensure that the density was within acceptable parameters,
indicating a substantially homogenous dispersion of the particles
in the foam.
[0086] The composition was transferred to the desired level in the
holding vessel of the filling apparatus equipped with an auger
having 7 flights. The distance between the flights at the upper
portion of the screw was about 3.75 cm, while the distance between
the flights at the lower portion of the screw was about 1.5 cm. The
composition then was dispensed into syringes by way of the auger
screw. Approximately 6 milliliters (ml) of composition was placed
in each syringe. The filling was performed using the syringe
filling apparatus at a rate of approximately 36 ml/minute to about
72 ml/minute. The holding vessel was replenished with fresh
flowable hemostatic composition as the level gradually decreased.
Upon completion of the filling procedure, the density of the
flowable hemostatic composition in the syringe was measured as
described above. Results are reported in Table 9.
Example 12
[0087] Two liter of a saline solution containing 0.005% by weight
of benzalkonium chloride and 5% weight of glycerol were poured into
a mixing vessel (Ross Mixer, Model DPM2, Serial #75308) and the
mixer blades engaged in an operating mode. Nitrogen gas was
introduced into the solution via a tube connected to a nitrogen
source in a continuous bubbling manner. The mixture of solution and
gas was stirred at 70 Hz for approximately 10 minutes in order to
form a foam as described herein above. The addition of the solid
particles was commenced after formation of the foam using an
addition-funnel attached to the entry port of the mixing vessel.
400 grams of gelatin powder were added over a time period of about
5 minutes. The mixing was continued for about 10 minutes after
total powder addition at 70 Hz, followed by additional mixing for
about 2 minutes at a reduced blade speed of about 12 Hz. Upon
completion of the mixing, the density of the composition in the
mixing vessel was measured using the solvent method as described
above to ensure that the density was within acceptable parameters,
indicating a substantially homogenous dispersion of the particles
in the foam.
[0088] The composition was transferred to the desired level in the
holding vessel of the filling apparatus equipped with an auger
having 7 flights. The distance between the flights at the upper
portion of the screw was about 3.75 cm, while the distance between
the flights at the lower portion of the screw was about 1.5 cm. The
composition then was dispensed by way of the auger screw.
Approximately 6 milliliters (ml) of composition was dispensed into
each syringe at a rate of approximately 120 ml/minute. The holding
vessel was replenished with fresh flowable hemostatic composition
as the level gradually decreased. Upon completion of the filling
procedure, the density of the flowable hemostatic composition in
the syringe was measured as described above. Results are reported
in Table 9. TABLE-US-00009 TABLE 9 Effect of filling rate on the
density of paste Density of Paste (gm/ml) Syringe Rate of filling
Number 12 ml/min 18 ml/min 36 ml/min 72 ml/min 120 ml/min 1
<0.659 <0.626 <0.626 <0.626 <0.626 10 <0.695
<0.626 <0.626 <0.626 <0.626 15 <0.703 <0.703
<0.626 <0.626 20 <0.703 <0.703 <0.626 <0.626 25
<0.703 <0.703 <0.626 <0.626 30 <0.718 <0.703
<0.659 <0.626 35 <0.745 <0.718 <0.659 <0.626 40
NA <0.718 <0.659 <0.626 50 NA NA <0.659 <0.626
<0.626 60 NA NA <0.703 <0.659 80 NA NA <0.703 <0.659
100 NA NA NA <0.703 <0.626 120 NA NA NA <0.703 140 NA NA
NA <0.703 150 NA NA NA <0.703 <0.626 600 NA NA NA NA
<0.626 *: Density of paste measured as extruded out of the
Auger. Each exudate is approximately 6 ml in volume.
[0089] Table 9 demonstrates the effect that the rate of filling may
have on the resulting density of the paste. It first is noted that
for a particular rate of filling, i.e. number of syringes filled
per minute, the density of the composition indicated to be less
than a particular value for the particular number of syringe is
greater than the density value measured at the previous number of
syringe. For example, at 12 ml/minute, the density of the
composition in the 25.sup.th filled syringe is less than 0.703 but
greater than 0.659. It is noted that at higher filling rates, the
consistency of the composition may be maintained within acceptable
parameters over longer periods of time. As noted, at a higher
filling rate, e.g. 72 ml/minute, the density of the composition is
maintained to be no greater than 0.703 g/ml at the 150.sup.th
syringe filled, while at a filling rate of 12 ml/minute, the same
relative change in the density of the composition is noted at the
25.sup.th syringe filled. It is noted that the particular rates of
filling noted herein are applicable to the particular apparatus and
compositions disclosed herein and may in fact vary depending on
apparatus design and composition.
* * * * *