(12) United States Patent
Azevedo
US006849082B2
US 6,849,082 B2
*Feb. 1, 2005
(10) Patent N0.:
(45) Date of Patent:
(54)
(75)
(73)
(*)
(21)
(22)
(65)
(51)
(52)
(58)
(56)
METHOD FOR CURING CYANOACRYLATE
ADHESIVES
Inventor:
Max Azevedo, Lenoir, NC (US)
Assignee: Spartan Products Inc., Rye, NY (US)
Notice:
Appl. No.:
Filed:
Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 379 days.
This patent is subject to a terminal dis-
claimer.
09/982,226
Oct. 19, 2001
Prior Publication Data
US 2003/0077386 A1 Apr. 24, 2003
Int. Cl.7 .............................................. .. A61B 17/08
.. 606/214; 606/213
Field of Search ............................... .. 424/422, 423;
606/214, 213, 88, 92-95; 156/325, 331;
2,912,454
3,667,472
3,903,055
3,975,422
3,995,641
4,003,942
4,012,402
4,013,703
4,041,063
4,057,535
4,182,823
4,328,170
4,444,933
4,818,325
5,039,753
References Cited
U.S. PATENT DOCUMENTS
>>>>>>>>>>>>>>>
*
11/1959
6/1972
9/1975
8/1976
12/1976
1/1977
3/1977
3/1977
8/1977
11/1977
1/1980
5/1982
4/1984
4/1989
8/1991
5,192,536 A 3/1993 Huprich ................. .. 424/78.08
5,254,132 A 10/1993 Barley et al. .. .... .. 606/214
5,328,687 A 7/1994 Leung et al. .. 424/78.35
5,403,591 A 4/1995 Tighe et al. . . . . . . . . . . .. 424/445
5,475,110 A * 12/1995 Hudkins et al. .... .. 546/256
5,684,042 A 11/1997 Greff et al. ............... .. 514/527
5,749,956 A * 5/1998 Fisher et al. . 106/287.28
5,807,563 A 9/1998 Askill et al. .... .. 424/402
5,928,611 A 7/1999 Leung 422/131
5,944,754 A 8/1999 Vacanti ..... .. 623/11
5,981,621 A 11/1999 Clark et al. 523/118
6,086,906 A 7/2000 Greff et al. ............... .. 424/407
(List continued on next page.)
FOREIGN PATENT DOCUMENTS
WO 96/ 14292
OTHER PUBLICATIONS
WO 5/1996
Collins, J .A. et al., “Biological Substrates and Cure Rates of
Cyanoacrylate Tissue Adhesives”, Archives of Surgery, vol.
93, Iss. 3, Sep. 1966, pp 438-32.
(List continued on next page.)
Primary Examiner—Julian W. Woo
528/480 Assistant Examiner—Jessica R. Baxter
(57) ABSTRACT
A new adhesive method using an adhesive composition
including cyanoacrylate adhesive and a stabilizing agent to
g°1Ke°V°r “““““““ " 122680/343645‘: join together portions of a substrate, particularly useful in
Bag?“ ”””””””” " / suturing and similar medical procedures, is disclosed. It is
Buck 260/465 4 based on the discovery that remarkable improvements are
Kmnenthal et al. ...... N 128/335 obtained by.adding a step of removing stabilizing agent from
Buck ........................ N 260/464 such adhesive compositions C01I1C1dCI1tly. with the prior
Buck ,, 260/448,2 known steps of (a) providing an adhesive composition
Buck 260/464 including cyanoacrylate adhesive and a stabilizing agent, (b)
Buck ..................... .. 260/465.4 presenting a substrate to receive at least a portion of such
LiPat0Va Ct a1~ 260/775 AC cyanoacrylate adhesive and (c) applying such portion to the
Schoenberg """"""" " 526/298 substrate. Devices for use in performing the method are
Okawara et al. .. 260/465.4 disclosed
Columbus et al. .. 524/292 '
Hiraiwa et al. . 156/315
Woods et al. .......... .. 525/330.3 9 Claims, 2 Drawing Sheets
Ml
1 6
1 4
/4
8\_/
US 6,849,082 B2
Page 2
U.S. PATENT DOCUMENTS
6,090,397 A 7/2000 Lee et al. ................. .. 424/405
6,099,807 A 8/2000 Leung . . . . . . . . . . . . .. 422/131
6,143,352 A 11/2000 Clark et al. . . . . . . . . . .. 427/2.1
6,143,805 A 11/2000 Hickey et al. .. .. 522/152
6,217,603 B1 4/2001 Clark et al. . . . . . . . . .. 606/214
6,245,933 B1 6/2001 Malofsky et al. .. 558/381
6,248,800 B1 6/2001 Greff et al. ....... .. 521/71
6,294,629 B1 * 9/2001 O’Dwyer et al. 526/297
6,310,166 B1
2003/0158579 A1
2003/0158580 A1
OTHER PUBLICATIONS
10/2001 Hickey et al. ......... .. 526/348.2
8/2003 Azevedo
8/2003 Azevedo
Leonard, F. et al., “Interfacial Polymerization of n-Alkyl
X-Cyanoacrylate Homologs”, Journal of Applied Polymer
Science, vol. 10, Iss. 11, Nov. 1996, pp-1617-23.
Woodward, S.C. et al., “HistotoXicity of Cyanoacrylate
Tissue Adhesives in the Rat”, Annals of Surgery, vol. 162,
Iss. 1, Jul. 965, pp-113-22.
Cameron, J.L. et al., “Degradation of Cyanoacrylate Tissue
Adhesive, pt. 1”, Surgery, vol. 58, Iss. 2, Aug. 1965, pp
424-30.
Leonard, F. et al., “Synthesis and Degradation of Poly(alkyl
X-Cyanoacrylates)”, Journal of Applied Polymer Science,
vol. 10, Iss 2, Feb. 1966, pp 259-72.
Leonard, F. et al., “Synthesis and Degradation of Poly(alkyl
X-Cyanoacrylates)”, Journal of Applied Polymer Science,
vol. 10, Iss 2, Feb. 1966, p 1214.
Lehman, R.A.W. et al.,“ToXicity of Alkyl 2—Cyanoacry-
alates, Pt. 1”, Archives of Surgery, vol. 93, Iss 3, Septe
1996m pp 441-46.
Yonezawa, M. et al., “Studies on X-Cyanoaculate, Pt. 6:
Reaction of Cyanoacetate with Formaldehyde” Yuki Gosei
Kagaku Kyokaishi, vol. 25, Iss 4, Apr. 1967, pp 311-16.
Leonard, F, “Hemostatic Applications of Alpha Cyanoacry-
lates: Bonding Mechanism and Physiological Degradation
of Bonds”, Adhesion in Biological Systems, ed. R.S. Manly,
1970, pp 185-99.
Vezin, W.R. et al., “Diffusion of Small Molecules in
Poly-n-Alkyl Cyanoacrylates”, Journal of Pharmacy and
Pharmacology, vol. 30, Iss Suppl, Dec. 1978, p 2P.
Vezin, W.R. et al., “In Vitro Heterogeneous Degradation of
Poly(n-Alkyl X-Cyanoacrylates)”, Journal of Biomedical
Materials Research, vol. 14, Iss 2, Mar. 1980, pp 93-106.
Tseng, Y.C. et al., “Modification of Synthesis and Investi-
gation of Properties for 2-Cyanoacrylates”, Biomaterials,
vol. 11, Iss 1, Jan. 1990, pp 73-79.
* cited by examiner
U.S. Patent Feb. 1,2005 Sheet 1 of 2 US 6,849,082 B2
Sheet 2 of 2
U.S. Patent
US 6,849,082 B2
Feb. 1,2005
F|G.5
US 6,849,082 B2
1
METHOD FOR CURING CYANOACRYLATE
ADHESIVES
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to a new method of curing
stabilized cyanoacrylate adhesives coincidently with their
application to a substrate, particularly with reference to
medical procedures using such adhesives and new devices
for using the method.
2. Description of the Prior Art
Medical interest in cyanoacrylate polymers was apparent
in the mid-nineteen sixties as evidenced by numerous
reports on its use as a tissue bonding agent. Collins, et al
reported on the effectiveness of homologous chain
cyanoacrylates for bonding of biological substrates (1,2).
They observed high rates of polymerization with longer
chain esters than the methyl or ethyl monomers. There
appeared to be more biocompatability with the longer chains
as noted by the ease of spreading monomer films on bio-
substrates. This contrasted with in vitro polymerizations
where the lower homologues reacted much faster. There was
particular interest in the degradation of these polymers as
they related to possible harmful effects that would preclude
their use in surgery. Woodward, et al (3) reported histotox-
icity of these monomers in rat tissue. The study involved in
situ polymerization of three cyanoacrylate monomers:
methyl, hexyl, decyl. It was reported that histotoxic effects
were greatest with methyl and decreased with the other two
monomers.
The same group reported on the use of radioactive methyl
cyanoacrylate for monitoring routes for the loss of the
polymer (4, 5). Results indicated that the polymer was
degraded and excreted principally through the urine and
feces. Analysis of the animal’s organs revealed no signs of
radioactivity. This implied no degradation products were
incorporated into any of the animal’s metabolic pathway. By
analogy to poly-vinylidene cyanide, they noted that the
cyanoacrylate polymer degraded in the presence of water
and more so in the presence of bases. The first observed
degradation product turned out to be one of the starting
materials, i.e., formaldehyde. In vitro studies have shown
that the polymers degrade via hydrolytic scission in homo-
geneous as well as heterogeneous conditions These
degradation products were confirmed to be formaldehyde
and the corresponding cyanoacetate. The conditions of solu-
tion degradation affected the consequent rates, namely,
under neutral conditions rates decreased as the homologous
series was ascended while alkaline conditions increased all
rates.
The same study reported that the hydroxyl group was
evident in the polymer as the initiating species. This was
concluded from infrared spectral data that displayed
hydroxyl group absorption at 3600 cm(—1). Further support
for this is the noted suppression of the OH as water is
replaced with methanol and the observed methoxy absorp-
tion at 1100 cm(—1). Preferential initiation was shown to
occur with NH2 containing substances such as pyridine,
cysteine, alanine, and glycine in aqueous solutions. This
suggested that in vivo adhesion was more than a mechanical
interlocking of the solid polymer with the tissue. This
appears to be the case as it was noted that typical polymer
solvents were not effective in solvating tissue-bound poly-
mer.
From this it would appear that in vivo studies of degra-
dation do not necessarily correspond to in vitro conditions.
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Part of the degradation mechanism relies on the solution of
polymer for hydrolytic scission. The chemical bonding of
the polymer excludes this surface from hydrolytic activity. A
mechanism of degradation was proposed that suggests an
action similar to unzipping in acrylics, however, the differ-
ence being that the monomer is not regenerated. The pro-
posed mechanism necessitates the presence of the hydroxyl
as well as the presence of water.
An unusual effect was reported regarding the aqueous
degradation of isobutyl cyanoacrylate Of the monomers
tested (methyl, propyl, butyl, isobutyl, heptyl, octyl), it was
the only one that degraded more rapidly than any of the
unbranched homologues, with the exception of the methyl.
A second study reported that in vivo experimentation give
credence to the chain scission mechanism by hydrolysis
When beta-(14) carbon tagged cyanoacrylate is implanted in
rats, radioactive urea is isolated from urine. This suggests
that tagged formaldehyde is released, converted to carbon
dioxide and in turn reacts with ammonia to produce urea
Rates of degradation on ethyl, butyl, and hexyl
cyanoacrylates were evaluated with regards to molecular
weights, concentrations, and side chain structures (10). The
method employed buffered systems of pH ranges from 5.97
to 7.88. As expected, the rates increased with increasing pH.
Scanning electron microscopy of the degraded polymer
indicated that reaction occurs at the surfaces and not inter-
nally through diffusion. It was postulated that the greater the
length of the nalkyl side chain, the more protection provided
to the labile hydroxyl end of the polymer chain. This in turn
would provide greater resistance to degradation of the
polymer. Degradation rates do in fact correspond to chain
length protection. The relative rates of degradation for
hexyl, butyl, and ethyl were, respectively, 1.0, 1.36, 9.55.
The same group reported on a study whereby degradation
rates were retarded by increasing the chain length of the
polymer (11). Very small quantities of impurities in the
monomers had a significant impact on the final outcome of
the degree of polymerization. Further to this study, within
the ethoxyethyl system, longer chain length enhanced the
degradation resistance of the resultant polymer.
A comparative study of ethyl cyanoacrylate and polyure-
thane in-situ generated adhesives and coatings were reported
in U.S. Pat. No. 4,057,535. The study claimed the superi-
ority of the polyurethane structure due to high flexibility and
compatibility with the treated tissues. The single comparison
was made with incised tissue and consequent application
between the wound edges. Inferiority of this application for
the cyanoacrylate was readily evident, but true topical
applications were not compared. Of eleven examples given,
four were of a topical method, yet no data was presented as
no application of the ethyl or any other homologue was done
conjunctively for comparative efficacy. A further deficiency
of this patent is the practicality of use. No indication is given
for a device to properly apply the two part system and
appears to indicate an at-site preparation.
Another patent, U.S. Pat. No. 5,192,536 overcomes the
apparent difficulty of U.S. Pat. No. 4,057,535 by taking
preformed polyurethane and dissolving in a rapidly evapo-
rating solvent such as tetrahydrofuran. The composition is
designed to form a “membrane-like cover over the wound”
and “assists in maintaining closure of the wound”. Again no
comparative studies were reported.
U.S. Pat. No. 3,995,641 presents the novelty of modified
cyanoacrylates, namely, carbalkoxyalkyl cyanoacrylates.
These also are claimed to be useful for tissue adhesives in
surgical applications. The presumed superiority of these
US 6,849,082 B2
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products was attributable to the rapid hydrolytic decay and
concurrent low degree of histotoxicity. Since no data is
presented regarding formaldehyde evolution it is presumed
that the hydrolysis mechanism does not scission the polymer
to generate it.
U.S. Pat. No. 5,254,132 discloses the use of a hybrid
method of surgical application of cyanoacrylates. It claims a
combination of sutures and adhesive such as to be mutually
isolated from each other, but to both support the re-growth
of the tissue in the wound area. It addresses the issue of
insuring no contact of adhesive in the suture area so as to
assure no inclusions of the cyanoacrylate. This method
would appear to be awkward and cumbersome and require
a very effective and controlled dispensing of the adhesive
without contacting the suture. Additional concern is indi-
cated as a suggestion is made to employ a solvent (acetone)
if any surgical instrument happens to be bonded inadvert-
ently to the treated area.
U.S. Pat. No. 5,328,687 attacks the formaldehyde issue by
incorporating a formaldehyde scavenger such as sodium
bisulfite. The various compositions were evaluated via
in-vitro experimentation. The examples presented all had a
presumably excessive level of scavenger. The representative
compositions had loadings of 20% of a scavenging agent
that was designed to offset formaldehyde emissions that
were at 0.1%. As indicated previously, in-vitro and in vivo
conditions are not identical and certainly not in this instance.
The presented in-vitro conditions do not factor in the
dynamic conditions in living tissue. The surgically treated
area would be under continuous and changing fluids as the
organ attempts to bring in the necessary biocomponets to
heal the traumatized tissue. As such, it would not be
expected that the scavenger/formaldehyde ratio would be
maintained as it was in the in-vitro state. It could be
speculated that the use of such high loadings of any fluid
solubilized additives would contribute to greater formalde-
hyde emissions. This can be assumed to be a consequence of
dissolution of the additives resulting in cavities in the
polymer thereby promoting greater surface area for hydro-
lytic degradation.
U.S. Pat. No. 5,403,591 concerns the use of cyanoacry-
lates for treatment of skin irritations that progress to ulcer-
ations. It would be assumed that these conditions could be
considered wound formations, e.g., see U.S. Pat. No. 3,995,
641.
U.S. Pat. Nos. 5,928,611, 5,981,621, 6,099,807, 6,217,
603 describe methods of inducing cure of cyanoacrylates by
passing the adhesive through a porous applicator tip con-
taining substances that initiate the polymerization.
U.S. Pat. No. 6,143,352 describes methods of altering the
pH environment of cyanoacrylates in order to attenuate or
accelerate the rate of hydrolytic degradation by uses of acid
and alkaline additives. The formulation of acidic modifiers
is problematic as they tend to inhibit the primary character-
istic of these materials, namely, rapid cure on application to
tissue. Data is presented on effects of acidic compositions on
previously cured cyanoacrylates.
All of these methods rely on addition of various compo-
sitions to effect the accelerated cure onto the desired sub-
strate. These may induce polymerization by creating a
greater number of initiation sites and or orientation of the
monomer for more facile polymerizations. Other plausible
mechanisms can be evoked, but the fact remains that these
materials become a part of the composition. As such these
chemical inclusions may elicit unfavorable reactions in the
cured state. In particular, the use of pH-based accelerators
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can now contribute to the alkaline hydrolysis of the
cyanoacrylate polymer.
This is particularly undesirable in medical applications of
the cyanoacrylates as the hydrolysis results in the evolution
of formaldehyde. A certain level of formaldehyde can be
tolerated by tissue as it is able to dispose of reasonable
concentrations. A solution to this was to increase the chain
length of the cyanoacrylate monomer side group and in
particular that it be alkyl so as to impart hydrophobic
character to the resulting polymer.
The current and prior art has been able to achieve a
synthesis of the octyl cyanoacrylate at economic levels for
applications in the medical field, although improbable for
uses in commercial applications due to reaction yields. A
number of methods have been attempted to improve yields
(12). The variables looked at included: azeotropes, tempera-
ture and formaldehyde/cyanoacetate ratio. Other methods
have also included assessment of different catalysts for the
condensation reaction. Regardless of the methods tried,
yields become increasingly smaller as the cyanoacetate
pendant group becomes larger.
A reported attempt to improve yields is reported in U.S.
Pat. No. 6,245,933. This method attempts to avoid yield
losses by producing the high yield cyanoacrylate prepoly-
mers of the lower homologues (methyl & ethyl) and then
proceed through a transesterification with a longer chain
alcohol such as the octyl. Three reported examples with
2-octanol gave yields ranging from 21.8% to 36.2% of crude
monomer.
From this, it can be seen that high yields are difficult and
no doubt subsequent workup to medically acceptable prod-
ucts result in even lower product output. The difficulty with
methods such as above, is the undesirable side products
which are difficult to remove from the main stream. In
particular, it is difficult to achieve complete transesterifica-
tion reactions on polymeric moieties because of steric
obstruction. As a consequence, purity is compromised as the
initial cyanoacrylate prepolymer is not completely reacted
and the lower homologue co-distills with the desired prod-
uct.
Other additives have been used to attenuate various
properties, such as modulus (elasticity), viscosity, thermal
resistance, etc. Each and every additive becomes a substance
that must be removed by the surrounding tissue, which
generally do not assist in recovery of the damaged area. In
that regard, the addition of these additives must factor the
property improvement against the effect on tissue compat-
ibility.
Objects
A principal object of the invention is the provision of a
new method for curing of cyanoacrylate adhesives.
A further object is the provision of such curing methods
that minimize presence of contaminates and extraneous
additives in the resulting cured adhesives with particular
reference to use in medical procedures.
Additional objects include:
1. Enhancing the cure speed of stabilized cyanoacrylate
adhesives by destabilization treatment that removes stabi-
lizers from them coincidently with their application onto a
substrate.
2. The provision of new cyanoacrylate adhesives curing
methods that allow for greater levels of stabilizers therein to
be formulated to provide improved shelf life while not
lowering speed of cure upon application.
US 6,849,082 B2
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3. Providing for greater latitude of storage of cyanoacry-
late adhesives in packages with less regard for handling
thereof.
4. Enhancing the cure speed of cyanoacrylate adhesives
by a destabilization treatment that purifies such adhesive
coincidently with the application onto a substrate.
5. Producing improved cured cyanoacrylate adhesives
that exhibit greater biocompatability as a consequence of
modified polydispersity, especially such adhesives that
exhibit attenuated degradation of the polymer thereby
exposing tissue contacting the adhesive to lower levels of
formaldehyde.
6. The provision of improved cyanoacrylate adhesives
curing methods that enable the use of difuncitional and/or
multifunctional cyanoacrylates to optimize properties such
as elasticity, porosity, cohesive strength and degradation
rates.
7. The provision of improved cyanoacrylate adhesives
curing methods that allow for greater degree of freedom in
concentration of stabilizers without affecting the final
chemical characteristics of such adhesives.
8. The provision of improved cyanoacrylate adhesives
curing methods that allow for formulating unadulterated
adhesives containing no plasticizers while achieving the
elastomeric properties necessary for bonded substrates
undergoing multidimensional stresses.
9. The provision of unique devices for use in carrying out
the new method of the invention.
Other objects and further scope of applicability of the
present invention will become apparent from the detailed
descriptions given herein; it should be understood, however,
that the detailed descriptions, while indicating preferred
embodiments of the invention, are given by way of illustra-
tion only, since various changes and modifications within the
spirit and scope of the invention will become apparent to
those skilled in the art from such descriptions.
SUMMARY OF THE INVENTION
These objects are accomplished in accordance with the
invention by the provision of a method for curing reactive
monomeric cyanoacrylate oligomers to undergo macromo-
lecular formations via appropriate destabilization coinci-
dently with their application to a substrate. Such destabili-
zation chemically and physically removes stabilizing agents
so the new method allows for greater levels of stabilizers to
be formulated for improved shelf life and not result in slower
curing speed upon application to a substrate. Further, this
allows for greater latitude of storage in various packages
with less regard for product handling.
Cyanoacrylate adhesives that exemplify this invention
comprise one or more monomers having the following
general structure:
CH2=C(CN)—C(O)—R
Without encumbering the body of this patent with specific
examples of moieties, reference is made to the numerous
patents delineating the myriad of groups that can be repre-
sented by the moiety designated as R. These are therefore
intended to define and be included by general reference to
such prior art and by those knowledgeable thereof.
This invention achieves this goal by removing stabilizers
in cyanoacrylate adhesives coincidently with their applica-
tion to substrates thereby making the resultant purified
compositions highly susceptible to polymerizations as a
result of contact with the substrates. In one embodiment for
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effectively using stabilized cyanoacrylate adhesives in
accordance with the invention, they are stored in a device
that houses a frangible ampoule containing such adhesives
separate from particulate agent that removes stabilizers from
the adhesive, but within the device. Alternatively, the fran-
gible ampoule may contain the particulate destabilizing
agent separate from the stabilized cyanoacrylate adhesive or
both the stabilized cyanoacrylate adhesive and the particu-
late destabilizing agent may be contained in separate
ampoules.
Such frangible ampoule containing devices may be con-
structed of any number of materials that can be shaped or
molded or otherwise fabricated to contain the adhesive and
ampoule. Also, it can be made from such materials as to
provide a resilient wall capable of transmitting pressure to
the frangible ampoule without loss of its containment prop-
erties. These application devices advantageously further
comprise a filtering component and nozzle for application of
the filtered and resulting destabilized adhesive to the sub-
strate.
The application devices preferably are designed to apply
the destabilized product in a continuous manner by appro-
priate removal of any destabilizing component. An example
of such a device is one that incorporates a removable
cartridge of the destabilizing agent with a reservoir of the
appropriate adhesive feeding through the cartridge.
In a preferred embodiment, one of the above described
devices containing isooctyl cyanoacrylate in the crushable
ampoule and a weak base anion exchange resin such as
“Ionac AFP329” (Sybron Chemicals, Inc.). The ampoule is
crushed and contents are intermixed so as to optimize
maximal contact with the isooctyl cyanoacrylate monomer
for a short period of time. Upon achieving the desired
consistency, the contents are then expressed through the
appropriate filter and dispenser tip onto the substrate, spe-
cifically living tissue, mainly human or animal flesh and
skin. The application is accomplished in such fashion as to
prevent encapsulation of adhesive by any surrounding tis-
sue. Though ultimately these inclusions are degraded and
excreted, it is most desirable to minimize this occurrence to
maximize reconstitution of the surrounding tissue. The need
to assure this minimization was noted in U.S. Pat. No.
3,667,472 which pointed out the requisite to bridge the
wound without diffusing into it. This was accomplished by
bringing the wound edges together followed by application
so as to effect a bridging over the wound to circumvent
necrosis and irritation by this technique.
A second preferred embodiment utilizes the above
described devices containing isodecyl cyanoacrylate, weak
base anion exchange resin, and an appropriate difunctional
cyanoacrylate to effect a composition capable of generating
sufficient multiaxial strength to maintain integrity of the
healing tissue.
Athird preferred embodiment utilizes the above described
devices containing isotridecyl cyanoacrylate and weak base
anion exchange resin as the destabilizing agent.
A fourth preferred embodiment includes the above with
combinations of cyanoacrylate monomers to achieve control
over the rate of hydrolytic degradation so as to improve
compatibility with tissue by control of formaldehyde emis-
sions.
In preferred embodiments, the invention employs particu-
late ion exchange resins, molecular sieves, zeolites,
chelators, and/or alkaline solids, particularly alkali metal
carbonates, as destabilizing agents to remove stabilizers
from solution in the cyanoacrylate adhesives. Advanta-
geously the size of these particulate destabilizing agents will
US 6,849,082 B2
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be of between Nos. 10 and 600 U.S. standard sieve series
size and they will be selected to produce destabilization of
the cyanoacrylate adhesive within about 1 to 5 minutes of
mixing the destabilizing agent(s) with the cyanoacrylate
adhesive.
Prior to use, the particulate destabilizing agent advanta-
geously is treated to assure removal of all extraneous
components that would cause initiation of polymerization.
For example, in the case of weak base anion exchange resin,
it is treated with distilled water followed by vacuuming to
0.20 mm Hg at 35-50 degrees centigrade.
The new method of the invention for curing stabilized
cyanoacrylate adhesives coincidently with their application
to a substrate is particularly useful in performing medical
procedures using such adhesives, e.g., suturing human or
animal flesh, providing wounds with protective covering,
etc. However, it may be used in other adhesive operations,
e.g., joining plumbing items, forming furniture joints, etc.
The objects are further accomplished in accordance with
the invention by the provision of unique devices for using
the method of the invention. Advantageously, such device is
one that (a) delivers the cyanoacrylate adhesive of conve-
nient viscosity by some degree of partial polymerization and
regulated by the interval from the destabilizing operation to
time of application, (b) contains a porous segment for the
containment of a frangible ampoule and other components
so as to permit the release of the destabilized adhesive with
no particulate components being released onto the substrate
to which it is applied, (c) delivers the destabilized adhesive
through a nozzle to an applicator tip configured for appro-
priate application onto the substrate, (d) is configured with
the adhesive in an isolated compartment separate from the
destabilizing agent(s), that is able to release contents into
contact with the destabilizing agents, (e) positions the desta-
bilizing component in a compartment through which the
ampoule-released adhesive passes as it is being delivered to
the applicator tip for transfer to the substrate and can be
used to destabilize monomer formulations prior to applica-
tion to effect the desired result.
A preferred embodiment of a device of the invention
comprises a syringe having an elongated tubular chamber
defined by a length of flexible tubing having a proximal end
and a distal end, a dispensing tip on said distal end, means
at the proximal end to apply pressure to said chamber, filter
means positioned between the dispensing tip and the
chamber, a frangible ampoule located within the chamber
contains stabilized cyanoacrylate adhesive and particulate
destabilizing agent is contained in the chamber external of
the ampoule.
In an alternate embodiment of the above described device,
the particulate destabilizing agent is contained in the
ampoule and the cyanoacrylate adhesive is contained in the
chamber external of the ampoule.
All of the preferred embodiments are meant to further
include all of the various additives useful in the alteration
and improvements to cyanoacrylate adhesives as would
make them suitable for placement into the above devices and
modifications to these devices. These can include
plasticizers, stabilizers, surface insensitive additives,
tougheners, thickeners, adhesion promoters and other such
compositions as would be evident to those familiar with the
cyanoacrylate adhesives art.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the invention can be
obtained by reference to the accompanying drawings in
which:
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FIG. 1 is a lateral view, partially in section, of a device
used in accordance with the invention for curing stabilized
cyanoacrylate adhesives coincidently with their application
to a substrate.
FIG. 2 is a lateral view of second embodiment of the
dispensing end portion of a device as illustrated in FIG. 1.
FIG. 3 is a lateral view of third embodiment of the
dispensing end portion of a device as illustrated in FIG. 1.
FIG. 4 is a lateral view of fourth embodiment of the
dispensing end portion of a device as illustrated in FIG. 1.
FIG. 5 is a lateral view, partially in section, of another
device used in accordance with the invention for curing
stabilized cyanoacrylate adhesives coincidently with their
application to a substrate.
DESCRIPTION OF PREFERRED
EMBODIMENTS
With reference in detail to the drawings in which generic
components are designated by an arrowhead line and spe-
cific components by a plain line, FIG. 1 shows a first
embodiment of a device 2 of the invention for performing
the new methods of the invention comprising syringe 4
having a pliable tubular section 6 partially defined by a
proximal end 8 and a distal end 10 capped with a discharge
member 12 defined by a dish portion 12a and tapered portion
12b plus a funnel 12c structured to operatively engage the
tapered portion 12b.
A washer-like member 14 caps the proximal end 8 and
admits a plunger 16 with a distal end 17 that proximally
defines a chamber 18. A filter disc 20 fixed in the distal end
10 distally defines the chamber 18 within the tubular section
6.
The chamber 18 encloses a frangible ampoule 22 and a
quantity of particulate destabilizing agent 24 as defined
herein as an essential material of the invention. The ampoule
is precharged with an adhesive composition 26 comprising
cyanoacrylate adhesive and a stabilizing agent in accordance
with the invention thereby being separated from the particu-
late destabilizing agent 24 until such time as the ampoule 22
is fragmented in carrying out the new method of the inven-
tion.
To accommodate different variations of adhesive appli-
cation to substrates in accordance with the invention, the
discharge member 12 can be variously structured. Thus,
FIG. 2 illustrates a discharge member 12A similar to mem-
ber 12, but having a hemispheric porous filter tip 12d. Also
in FIG. 3, the discharge member 12B has a slotted end 126
to create a ribbon discharge of destabilized adhesive com-
position from the device 2 and in FIG. 4 the discharge
member 12C has a nipple end 12f for drop dispensing of
destabilized adhesive composition.
FIG. 5 shows a second embodiment of a device 30 of the
invention for performing the new methods of the invention
comprising syringe unit 32, a control valve 34 connected
thereto by fluid line 35, a pressure source 36 connected to
valve 34 by fluid line 37 and a suction source 38 connected
to valve 34 by fluid line 39. Advantageously, valve 34 can
be a foot operated type so a surgeon using the device 30 will
have both hands free in to apply destabilized adhesive
composition to a substrate in accordance with the invention.
Syringe unit 32 has a pliable tubular section 40 partially
defined by a proximal end bulb 42 and a distal end 44 capped
with a nozzle 46.
A filter disc 48 is fixed in the distal end 44 and distally
defines an operation chamber 50 together with the tubular
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section 40 and the bulb 42. The chamber 50 encloses a
quantity of particulate destabilizing agent 52 as defined
herein as essential material of the invention. In use, the
syringe unit 32 will suck a suitable amount of stabilized
cyanoacrylate adhesive into the chamber from a container
(not shown) through nozzle 46 when the valve 34 connects
line 35 to the suction source 38. By manipulation of the
pliable tubular section 40, indrawn adhesive (not shown) is
mixed briefly with the destabilizing agent 52. Then, valve 34
is carefully manipulated to intermittently connect line 35
with the pressure source 36 to force resulting destabilized
cyanoacrylate adhesive out of the chamber 50 via filter 48
and nozzle 46 onto the relevant substrate under the control,
for example, of a surgeon. Following such an operation, the
syringe unit 32 will be disconnected from the line 35 and be
discarded, while the remaining units 34, 36 & 38 will be
retained for repeated use with new syringe units 32.
The following preferred examples further disclose the
new method and display its effectiveness. In these examples,
all percentages are by weight unless otherwise indicated.
EXAMPLE 1
Aquantity of particulate destabilizing agent in the form of
suspension type, weak base anion exchange resin beads is
treated with distilled water followed by vacuuming to 0.20
mm Hg at 35-50 degrees centigrade to remove volatiles and
moisture.
Approximately 1.0 gram of iso-octyl cyanoacrylate
monomer is sealed in a frangible ampoule. Such cyanoacry-
late monomer has been stabilized with hydroquinone at
0.5%. The acid stabilizer, methane sulfonic acid, was intro-
duced previously into the cyanoacrylate monomer during its
synthesis at 0.25%. The cyanoacrylate monomer in the
ampoule and approximately 1.0 gram of the treated anion
exchange resin are individually introduced into a tubular
device referred to as a Tandem Dropper supplied by James
Alexander Company of Blairstown, N.J., that also provided
unsealed ampoules.
In order to filter matter dispensed from the dispenser tip
of the Tandem Dropper, it is plugged internally with a small
wad of polyester fiber also supplied by James Alexander
Company. The dispenser tip press fits onto the end of the
Tandem Dropper to contain the destabilizing agent and
ampoule. The assembled device is activated by crushing the
ampoule. The resultant mixture is then thoroughly mixed by
shaking so as to obtain optimal exposure of monomer to the
destabilizing agent. Then, a plurality of spaced apart drops
of the resulting destabilized adhesive are applied to human
skin on the back of a hand and the time for the resulting films
to undergone cure to a non-tacky surface is determined. The
destabilized adhesive undergoes cure in 5-15 seconds upon
application to the skin. This contrasts with untreated iso-
octyl cyanaocrylate monomer which shows no sign of cure
in 3 minutes.
EXAMPLE 2
Atwo milliliter plastic dispensing pipette is cut at the bulb
end to permit charging of destabilizing agent. The pipette is
a Number 3 obtained from Poly-Pipets, Incorporated of
Englewood Cliffs, N.J. A 1A: inch polyester fibrous plug as
described in Example 1, is inserted down into the narrow tip
portion and then 0.5 grams of anhydrous granular potassium
carbonate are charged into the pipette. The plug acts as a
filtration barrier to contain the granular potassium carbonate.
The bulb end of the pipette is heat sealed and the resultant
device is used to suction about 1 milliliter of iso-octyl
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cyanoacrylate monomer for mingling with the enclosed
particulate. The device is positioned with the tip vertically
upward and the components are intermingled by successive
squeeze and release actions for a short period of time. Upon
satisfactory mixing, the unit is used to apply the resulting
destabilized adhesive onto to skin as thin film portions on the
back of a hand. It is determined they undergo cure in 5-15
seconds. In contrast, untreated iso-octyl cyanaocrylate
monomer exhibits no signs of curing for periods of 3
minutes.
This example illustrates the use of multiple applications
of the adhesive from a supply of adhesive and disposable
pipettes and foregoes the need for a frangible ampoule or
other adhesive-isolating device.
EXAMPLE 3
A test was conducted on a wound accidentally caused by
a hot surface to the inside of the left forearm. The wound,
approximate dimensions of 1A: inch by 1.5 inches, had begun
to slough off the burned skin exposing the underlying tissue.
To evaluate the protective effect of the destabilized liquid
adhesive, the device of Example 2 was used to apply
destabilized iso-octyl cyanoacrylate adhesive. The wound
was overlayed with a thin film and cure took place in the
15-30 second range. The applied and cured cyanoacrylate
adhesive remained well attached for a period of days to the
injured skin while it served to protect the covered wound
area from irritation and infection by clothing or other contact
as well as promote the healing process. This contrasted with
prior experiences of similar wounds where the damaged
tissue did not heal well due to physical contact with sur-
rounding irritants such as clothing or other contact surfaces.
REFERENCES
1. J. A. Collins, et al., ARCH. SURG. Vol 93,428 September
1966
2. 2. F. Leonard, et al., J.A.P.S. Vol. 101617, 1966
3. S. C. Woodward, et al.,ANN. SURG. Vol. 162, July 1965.
4. 4. J. J. Cameron, et al., SURGERY, Vol. 58, August 1965.
5. C. H. McKeever, U.S. Pat. No. 2,912,454, Nov. 10, 1950.
6. 6. F. Leonard, et al., J.A.P.S., Vol. 10: 259, 1966
7. R. H. Lehman et al., ARCH. SURG. Vol. 93:441,1966.
8. M. Yonezawa et al., YUKI GOSEI KAGAKU
KYOKAISHI, Vol. 25, 1967.
9. F. Leonard, ADHES. BIOL. SYS. 1970.
10. W. R. Vezin et al., J. PHARM. PHARMACOL., Vol. 30,
1978, Suppl.
11. W. R. Vezin et al., J. BIOMED. MAT. RES., Vol. 93,
1980.
12. Yin-Chao Tseng et al., BIOMATERIALS, Vol 11, 1990
13. L.S. Pat. \o. 4,057,353
14. L.S. Pat. \o. 5,192,536
15. L.S. Pat. \o. 3,995,641
16. L.S. Pat. \o. 5,254,132
17. L.S. Pat. \o. 5,328,687
18. L.S. Pat. \o. 5,403,591
19. L.S. Pat. \o. 5,928,611
20. L.S. Pat. \o. 5,981,621
21. L.S. Pat. \o. 6,099,807
22. L.S. Pat. \o. 6,217,603
23. L.S. Pat. \o. 6,143,352
24. L.S. Pat. \o. 6,245,933
25. L.S. Pat. \o. 3,667,472
W at is claimed is:
1. A method of fabricating and using a cyanoacrylate
adhesive, comprising the following steps: (a) providing an
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adhesive composition comprising cyanoacrylate adhesive
and a stabilizing agent, (b) presenting a substrate to receive
at least a portion of said cyanoacrylate adhesive and (c)
applying said cyanoacrylate adhesive portion to said
substrate, the improvement which comprises the step of
removing stabilizing agent from said adhesive composition
coincidently with said application to said substrate, wherein
said step of removing stabilizing agent from said adhesive
composition consists essentially of contacting said adhesive
composition with a particulate agent and subsequently con-
taining said particulate agent and said stabilizing agent while
said cyanoacrylate adhesive is applied to said substrate.
2. The method of claim 1 wherein said cyanoacrylate
adhesive comprises one or more monomers having the
general structure CH2=C(CN)TC(O)TR.
3. The method of claim 2 wherein “R” is selected from the
group consisting of isooctyl cyanoacrylate, isodecyl
cyanoacrylate and isotridecyl cyanoacrylate.
4. The method of claim 2 wherein said cyanoacrylate
adhesive comprises a difunctional cyanoacrylate.
5. The method of claim 1 wherein said step of removing
stabilizing agent from said adhesive composition comprises
contacting it with particulate removal agent selected from
the group consisting of ion exchange resins, activated
charcoal, molecular sieves, zeolites, chelators, and alkaline
solids.
6. A method of fabricating and using a cyanoacrylate
adhesive, comprising the following steps: (a) providing an
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adhesive composition comprising cyanoacrylate adhesive
and a stabilizing agent, (b) presenting a substrate to receive
at least a portion of said cyanoacrylate adhesive and (c)
applying said cyanoacrylate adhesive portion to said
substrate, the improvement which comprises the step of
fragmenting a frangible ampoule to thereby bring said
adhesive composition in contact with a particulate agent that
removes said stabilizing agent from said cyanoacrylate
adhesive and subsequently removing said stabilizing agent
from said adhesive compositon coincidently with said appli-
cation to said substrate, wherein said step of removing said
stabilizing agent from said adhesive composition consists
essentially of contacting said adhesive composition with
said particulate agent and subsequently containing said
particulate agent and said stabilizing agent while said
cyanoacrylate adhesive is applied to said substrate.
7. The method of claim 6 wherein said ampoule contains
said cyanoacrylate adhesive separate from said particulate
agent.
8. The method of claim 6 wherein said ampoule contains
said particulate agent separate from said adhesive compo-
sition.
9. The method of claim 6 wherein said substrate is living
tissue.