Note: Descriptions are shown in the official language in which they were submitted.
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Our ref. : ~ 546
Case : GEE-445;~File 237 734
ETHICON, INC.
Somerville, Bridgewater Townshipj N.J., USA.
"Injectable e~bolization and occlusion solution"
The present invention relates to an inJectable embolization and occlusion
solution, which serves for the selected closure of organs, their duct
systems, or blood vessels, and is introduced to the required site in a
simple way with the aid of cannul&s, catheters, endoscopes, or suitable
applicators under X-ray control, and i8 precipitated there ln the
aqueous medium, in order to stop the flow of secretions from, or the flow
of blood to, the appertaining organs or parts of' an organ, staunch acute
internal bleeding, completely obliterate pathologicall~y modified sections
of vessels, or temporarily or definitively block these or fill them ~ith
a biological material. I~4 a radioactive substance or an artificial iso-
tope such as 133I with a suitable half-life and/or a cytostatic agent are
added to the solution according to the invention, then the therapeutic
effect obtained by cutting off the blood suppl~ in the embolization of
blood vessels supplying a tu~our is reinf'orced by the ~ixed radioacti~e
substances and cytostatic agents, distributed in the entire arterial
tree. The addition of an artificial isotope with a shorter hal4-life can
serve the purpose of not only radiation therapy but also of diagnosis.
.
Occlusion of the pancreatic ducts for the separate elimination of the
secretory function of the pancreas has so far been possible only by a
transduodenal suture o~ the orifice of the ductus pancreatlcus with a
purse-string ligature, with subsequent plastic shaping of the papilla,
or else by a complete pancreaticoduodenectom~, ~ith the relevant associated
interventions. Attempts have also been made to effect the transduodenal
occlusion of the terminal section of the ductus pancreaticus by the
in~ection of a plastic. The operations for the treatment of chronic and
acute pancreatitis place a very great strain on the patients and cannot
be done at an ad~anced age. The ligation of the ductus pancreaticus has
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led to acute pancre~titis in most cases; the occlu3ion with a plastic
has not yet been fully success~ul without the occurrence of side sffects.
Another disadvantage of both methods is that pancreatic fistulae can be
for~ed after the removal of biopsy samples for differential diagnosis
(chronic pancreatitis - pancreatic carcinoma).
Arterial catheter embolizatio~ has so far been carried out in the case of
renal carcinoma (pre-operatively and palliatively), gastrointestinal
bleeding, renal bleeding (arteriovenous ~istulae), pelvic fracture, bone
tumours, varicose bleeding, vaginal bleeding (in the case of portio
carcinoma), and intracerebral arteriorenous fistulae.
The ideal embolizing material is not yet available. A wide variety of
substances have been used, such as autologous thrombi, plastics, synthetic
substances (e.g. polystyrene, polyurethanes, ~olyvinyl alcohol, or
silicone resins), autologous muscle fibres, fat, fibrin foam, gelatin
foam, aIkyl cyanoacrylates and isopropyl palmitate (cf. M. The}en et al.,
Fortschr. Rontgenstr., vol. 124, 3 (1976), pp. 232-235). In practice,
these substances have been found unsatis~actory in their technical
application. The introduction of solids with -the aid of a catheter is
difficult. The absence of X-ray contrast media makes monitoring problem-
atic. In the case of alkyl cyanoacrylate monomers it is dif~icult to
control spontaneous polymerization.
The aim of the present invention is to provide an in~ectable embolization
and occlusion solution, which is applied at the right viscosity and then
made to solidify at the required site in the vessel. This is done on the
basis of the surprising discovery that, when a solution containing a
substantial amount of a prolamine is used, reliable closure of organs,
their duct systems, or blood vessels is obtained without the occurrence
of side effects. Another aim of the present invention is to provide a
process for the closure of organs, their duct systems, or blood vessels in
animals and man with the aid of an in~ectable embolization and occlusion
solution, which process ensures a reliable closure without the occurrence
of side effects.
The present invention thus relates to th~ subJect described in the Claims.
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The embolization and occlusion ~olution is prepared ln practice as
~ollow5
The physiologic~lly compatible solvent ~- preferably a mixture of
uater and an alcohol with 2-5 carbon atoms -- is made ready for use. I~
a contrast medium, a cytostatic agent7 an an-timicrobial substance, or a
specific pancreas inhibitor is to be used, it i5 added to the solvent in
the required amount. The prolamine is dissol~ed in the solvent with care-
ful stirring. The p~ of the solution is ad~usted to about 6.5-6.8 and pre~
ferably to about 6.65, uith a physiologically com~atible acid or base.
The density of the solution at 25~C is about 1.05-l.l and preferably
1.08 g/ml. The viscosity of the solution at 25C i5 about 350-oO0 and
preferably ~00-500 centipoise. The viscosity is checked after 12-14 h.
If the viscosity of the solution is to be raised, a physiologically
compatible oil is added at this point, with careful stirring. The solution
is then ready for use and can be poured e.g. into am~oules or small bottles.
Directly before the filling operation a conventional sterilizing agent
such as propylene oxide may be added to the solu-tion.
In experiments in which the solution according to the invention was
injected into the ductus pancreaticus no pancreatic fistula has yet
occurred in any of the cases.
In the case of an infected duct system closure of the duct is not possible
because of the risk of acute pancreatitis. ~Ihen a pancreatic cyst is
present there is a danger that it uill be enlarged and will rupture.
~one of the disadvantages mentioned here occurred when the solution
according to the invention was used in animal experlments. The pancreas
treated in this way never developed acute pancreatitis. The pancreatic
tissue re-formed without any change in the structure and function of the
islet cells. In contrast to the case of complete pancreatoduodenectomy,
where the island organ is removed, only in ver~ rare cases has the long-
term treatment of diabetes that develops been successful.
Pancreatitis uas produced b~ artificial infection in animal experiments
on dogs. It was found, surprisingly, that the symptoms rapidly disappeared
after the occlusion of the infected pancreas by the introduction of the
solution according to the invention. The first clinical trials on human
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subJects indicate that the therapy of pancreatitis in man ~s al~o
possible.
Prolamines form the main protein components of cereal grains and flour.
Unlike all other proteins, the~ can be extracted from flour ~rith 80%
alcohol, but they are insoluble in absolute alcohol and water. The most
important prol~mines are zein, gliadin, and hordein. Zein is pre~erred
in the prese~t invention.
The prolamine, preferably zein, can be used in an amount of 3-60 and
preferably 5-45 wt-%.
It has been found, surprisingly, that the solution accordine to the present
invention, which contains a prolamine, is particularl~ suitable~ because
prolamines are physiologically harmless substances that can be applied
in the liquid form with an ad~ustable viscosity and then solidify at the
required site in the vessel.
UnliXe all other proteins, prolamines are soluble in dilute alcohols and
other solvents, but they are insoluble in water. Example~ of solvents for
prolamines are C2-C5 alcohols (methanol dissolves them only to a small
extent and denatures them), ethylenediamine, l-acetylpiperidine, ethylene
glycol, propylene glycol, glycerol, N-methylacetamide, form~ide, hydra-
zine, dimethylformamide, and dimethyl sulphoxide. When choosing the
solvent for the occlusion solution according to the invention, the optimal
suitability of the solvent as regards its physical properties and precipi-
tation mechanism must be weighed against its possible toxicity. The
preferred solvent is a mixture of ethanol and water, and the amount of
water can vary between 4 and 50~, according to how quic~ly the prolamine
is to precipitate out.
In ethanol, prolamines form viscous and slightly thixotropic solutions.
~t a constant prolamine content, the viscosity of the solutions increases
with increasing ethanol concentration (see Table 1).
At a constant ethanol concentration the viscosit~ increases with increasing
concentration ~f the prolamine (Table 2).
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Table 1. Viscosity o~ a 35~ ~T/V zein solution in
50-95% v/v ethanol
Ethanol /~J V/Y Cp' (25C~
790
750
730
705
685
660
640
60Q
490
31~0
- . ........ . ,.. _... .
Table 2. Viscosity of 5-40% w/~ zein solutions in
60~ ~/v o~ ethanol
. cp (25C)
1$
38
78
160
265
475
Prolamines are decomposed into amino acids by hydrolytic cleavage.
The analysis of a zein hydrolysate shows that zein contains substantial
quantities of glutamic acid ~23%~, leucine ~1~%~, proline ~9%), and
L,alanine (9%~, but no lysine or tryptophan. Being proteins, prolamines
are expected to be absorbed by the body in ~ivo~ and this has in fact
been confirmed in animal experiments on rats and ra~its. Small rods made
of zein, with a length of 1-2 cm, were implanted intramuscularly, ~nd both
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the adsorption and the tissue reactions were compared with those
- observed after the implantation of catgut. ~e results showed that the
prolamine zein is absorbed in about the same per:iod of time, 4-6 weeks,
as catgut, and this process is accompanied by leucocyte infiltration,
which seems to be slightly more extensive in the case of zein. It has been
~ound, however, that this i5 not due primarily to zein but to impurities
present in commercial prol~mines. In particular, it is necessary to remove
the colouring matter of zein, i.e. 3,3'-carotenediol, by boiling in
petroleum ether.
Prolamines differ in their behaviour to some extent according to the
species and the variety of the cereal and the conditions under which the
plants grow and ripen. This circumstance must be taken into account when
making up a preparation. The decisive factor is not a ~xed concentration
but a certain ~iscosity of the prolamine in the solve~t used.
The molecular weight of prolamines is 25,000-407000. The viscosity of a
prolamine solution is undoubtedly connected with the molecular weight, but
so is ~lso the time of a~sorption. By cross-linking with tanning substances
such as chromic acids, formaldehyde and glutaric dialdehyde, the time of
absorption can be increased as desired; this also changes the solubility
of the prolamines and the properties of the gels made from them. Treat-
ment with ionizing radiation (2.5 Mrad) does not provoke recognizable
undesirable changes in prolamines. Even the viscosity of prolamine solutions
remains unchanged. Irradiation with gamma rays is the pre~erred way to
sterilize such solutions. However, the additïon of liquid propylene oxide
(0.5 - 1.0~ w/v) to prolamine solutions in a mi.xture of ethanol and water~lso ensures a satisfactory sterility without changing the consistency and
the compatibility.
In catheter embolization with prolamine solutions the aim is to adJust
the viscosity of the solution to the highest possible value, so as to pre-
vent the escape of the prolamine solution through the capillaries and
into the ~enous system. Furthermore~ the water content of the mixture of
water and solYent must be as high as possible, so that the prolamine is
precipitated as quickl~ as possible when it comes into contact with the
aqueous medi~m of blood. The solutio~s ~ust be thin enough to be applicable
through catheters ~2-4 Charr.~. Cohesion and adhesion must be so controlled
:
that no dra~m "thread" is fo~med when the catheter i~ being withdrawn
after the emboliæa-tion, and the embolus does not; adhere to the catheter.
This can be ensured by the addition of a physio].ogically compatible oil.
An example of such oils is groundnut oil, which considerably increases
the viscosity of the solution of prolamines in ethanol-water mixtures if the
amount of prolamine is kept constant with res~ect to the amount of solvent
(see Table 3), and even substantially more if the prolamine content is
kept constant with respect to the total amount of the preparation.
Vegetable oils are particularly suitable because they are physiologically
harmless and are metabolized in the body. Examples o~ oils that can be
used are groundnut oil, olive oil, poppyseed oil, and almond oil. The
amount of oil in an occluding solution according to the invention can be
between 5 and 45~ w/w. The oil is added to the ~rolamine solution after
the prolPmine has been completely dissolved. The use of an emulsi~ier
is not necessary, because prolamines have a certain emulsifying action.
Table 3. ~iscosity of 35% w/v zein solutions in 60~ v/v
ethanol after the addition of various amounts of
groundnut oil
Amou~t of groundnut .p ~2~ `
oil added (~" w/w)
_
0 450
710
890
1200
1450
. , _ _ _ _ . _____ _
The increase in viscosity depends on the viscosity of the oil added,
which in turn depends on the melting point. For exam~le, the addition of
the same amount of poppyseed oil and groundnut oil to a certain solution
of a prolamine in aqueous ethanol leads to different viscosities. Such
additions of oil do not only affect the viscosity, but also reduce the
adhesion and the internal elasticity of the prolamine solution~ This can
, . . .
be demonstrated on the change in the dripping rate ~num~er of drops per
minute) and the weight of the droplets when pouring zein solutions con-
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taining dif~erent amounts o~ oil (see l'able 4).
Table 4 Dripping rate and droplet weight of zein solutions
~ith different poppyseed oîl contents
_ _ _ _ _ . _ _ .
¦ PPpyseed oil, Drops/min Droplet ~ei~ht,
¦%, w/w mg
32 21
24 20
;25 20 18
16 i8
145 _ 12 16
The breaking-of~ at the catheter after the occlusion of th0 vessel can
thus be optimized by an appropriate choice o~ the nature and the propor-
tions o~ the components.
The addition o~ an oil also has another significance. Prolamines in
solution precipitate out in an aqueous medium in the form o~ relatively
solid blocks. ~en the solutions contain emulsified oils, however, oil
globules are trapped in the precipitated prola~ine block, imparting to it
a porous structure. This makes it easier for the body's connective
tissues to proliferate over them during the absorption process. There is
a quicker organization of the embolus, which ensures a definitive closure
of the vessel and excludes any re-canalization.
~ompounds that are soluble in water and in the solvent of the prolamine and
are customarily employed in angiography can be used as X-ray contrast media,
examples being sodium amidotrizoate (sodium N,N-diacetyl-3,5-diamino-2,4,6-
triiodobenzoate), 5-acetamino-2,4,6-triiodoisophthalic acid methyl amide-3,
sodium acetrizoate (sodium 3-acetamino-2,~,6~triiodobenzoate~ and sodi~m
2-iodohippurate. These do not change the basic characteristics and
especially the viscosity -- of prola~ine solutions (see Table 5~
The contrast medium enclosed in the precipitated prolamine block makes an
X-rat~ control of the occlusion possible not only during the application but
also at later times, in order to check its efficiency and the chanees that
have QC curred.
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~able 5. Viscosity o~ a 35% w/v zein solution in a 60~ ~/v
ethanol after the addition of various amount3 of an
X~ray contrast medium (sodium amidotrizoate)
_ _
Contrast medium
~sodium amidotrizoate), cp (25C3
% ~/v ... '.
_ ,
780
780
800
~0 810
_ _ .
When lone-term X-ray control is planned or desirable and the site favours
the escape of the soluble contrast medium by dif~usion, as for examrle,
in the case of a partial palliative renal embolization, one can use
water-insoluble contrast media such as barium sulphate or the contrast
media mentioned above but in the acid form instead of the form o~ sodium
salts. To prevent the sedimentation of the particles in the solution,
an accurate control o~ the particle size is therefore necessary. The
particles should be smaller than ~0 ~m(sieve No. I~oo, USP XIX).
Embolization of the supplying blood vessel leading to a tumour-containing
organ or part of an organ ensures isolation from the blood circulation,
and the prolamine is then distributed in the entire arterial system,
including the capillaries~ By the addition of cytostatic agents to the
occluding solution according to the in~ention, it is possible to localize
a high dose of the cytostatic agent in the region of the tu~our without
e.Yposing the RES (reticulo-enaothelial system) to the cytostatic agent,
which is by definition destructive. One can use as c~tostatic agents
either alkylating substances, such as Melphalan, Dichloren and Triaziquone,
or antimetabolites, such as folic acid antagonists, purine anta~onists, and
pyri~idine antagonists.
The antimicrobial substance can be almost an~ known drug of this kind,
2nd preferably an antibiotic or a sulphonamide, but also a quaternary
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ammonium compo~d. The concentration sho~d be a multiple of the ~C
(minimum inhibitory concentrationl o~ the substance for the microorganisms
expected in the case of the indication in question (e.g. 1000-10,000 ~g/ml
o~ streptomycin or 500~-50,000 yg/ml of penicillin G1.
To optimize the therapeutic effect aimed at by occluding t'ne ductus
pancreaticus in severe pancre~titis, one can add to the solution pancreas
inhibitors such as BAEE (benzoyl~1-arginine ethyl ester), TAME (p-toluene~
sulphon~l-l-arginine methyl ester), inter--globulin, or serum ~l-anti-
tr~psin.
The following examples serve to elucidate the present invention.
Exam~le 1.
Injectable embolizing solutions were prepared from the following
components:
A) Ethanol, 60% v/v250 ml
Sodium amidotrizoate 60 g
Zein 70 g
Poppyseed oil 50 g
Propylene oxide 4 g
B) Ethanol, 70%, v/v250 ml
Sodium amidotrizoate 65 g
Zein 60 g
Groundnut oil 60 g
Propylene oxide 4 g
C) Ethanol, 60% ~/Y250 ml
Amidotrizoic acid70 g
Zein 60 g
Groun &ut oil 60 g
Propylene oxide 4 g
The preparation o~ solutions A, B, and C started with measuring out the
ethanol in the re!quired concentration, after which sodium amidotrizo~te
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or the corresponding free acid was disso].ved in it. Instead of the
qodium salt, equimola~ ~uantities of the acid and NaOH can also be used.
The density and the pH were checked. Zein was added, with careful stir-
ring, and after complete dissolution (12-14 h~, the viscosity was
checked. The oil was then added and emulsified by stirring. ~he stirring
must be done carefully: too intense a stirring leads to the incorporation
o~ air and uncontroI~dchanges in viscosity. Propylene oxide (PO) was
added directly before the solution was poured înto ampoules or bottle~
~ith a beaded edge. One must make sure here that the temperature of the
solution is sufficiently low, in order to prevent evaporation of the
propylene oxide and thus uncontrolled variations in its concentration,
which could possibly endanger the sterility of thé finished solution.
ExamPle ?
Catheter embolization of the arteria renalis in the pig
_____________________.._____________ _ _________________
The catheter embolization of the arteria renalis was carried out i~ the
pig with 3.5 ml of a preparation according to the invention (35% w/v of
zein in 60% v/v o~ ethanol and 7% w/w of groundnut oil); 34 days later
the following findings were obtained:
The histological picture showed a considerable destruction of the renal
tissue, affecting the arteries, the ~edulla, and the renal cortex.
In the arter.ial lumens there were variously lar~e remains of the embolus
substance in the course of absorption, the rest being already extensively
absorbed.
The absorption occurred through leucocytic agglomerates penetrating the
lumen of the vessel in large numbers. The arterial walls ~ere destroyed
by leucocyte infiltration and granulation tissue, and their architecture
had been completely obliterated. The broad infiltrate and granulation tissue
also encroached on the adJacent veins, so that these were similarly
destroyed and often unrecognizable. The renal medulla was almost completely
covered by granulation tissue and fibrous organization, with massi~e
proliferation of fibroblasts and collagen fibre formation. The system
of efferent collecting tubules was extensively obliterated or made atrophic
by the fibrous organization? which partly affected the renal cortex as well.
In other respects the renal cortex showed bands of infarct necrosis, already
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described macroscopically. Thie destroyed renal tubules already showed ~
calcification in some cases.
The section of the arteria renalis exa~ined separately showed, in the
region of the border-shiaped wall thickening, similar changes in the
blood vessel, with circumscribed necrosis and granulation tissue, inclusion
of leucocytes, and proliferation of cormective tissue (histological stains:
haematoxylin-eosin, PAS reaction, elastica - ~an Gieson's stain).
Clinical trials have shown that a pre-operative emboli~ation of the
arteria renalis does not lead to any cc)mplications. A controlled closure
of the renal artery occurred, ~hich was confirmed on the subse~uent operative
extirpation of the organ. The operation was greatly facilitated by this
pre-operative embolization. Loss of blood and a possible escape of tumour
cells through the vena renalis were prevented. ~he embolization and its
monitoring on the X-ray screen presen-t no technical difficulties.
Similar results were obtained with the emboliæing solutions according to
Example 1.
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