Biocompatible material for medical apparatus comprising hydrophobically bound oil-soluble vitamin

A medical material which comprises an oil-soluble vitamin hydrophobically bound to a hydrophobic moiety containing macromer which is bound to the surface of a polymeric substrate via a copolymer is described. Suitable macromers include for example glycidyl methacrylate-linoleic acid. Suitable polymeric substrate materials include, in particular, cellulose. Methods for producing said medical material are also provided.

BACKGROUND OF THE INVENTION 
Field of the Invention 
This invention relates to a medical material, a method for the production 
thereof, and a medical apparatus which stably exhibits high 
biocompatiblility and excellent safety for a long time. 
In recent years, artificial internal organs such as artificial kidneys, 
artificial lungs, and blood separating devices have been produced and put 
to use. The materials of which these artificial internal organs are formed 
are required to possess excellent biocompatiblility. Use of an artificial 
internal organ destitute of biocompatibility is highly dangerous because 
the contact of the material thereof with blood or vital tissue has the 
possibility of injuring hemocytes in the blood and inducing the formation 
of plasma protein and thrombosis. For the impartation of biocompatibility 
to the materials forming artificial internal organs, therefore, various 
methods for reformation have been heretofore proposed. 
Particularly the practice of effecting graft polymerization by the use of a 
macromer has been recently in vogue. The formation of a graft copolymer, 
for example, has been attained by copolymerizing the macromer of a 
methacrylic ester with 2-hydroxyethyl methacrylate. It has been known that 
this graft copolymer has a better antithrombic property than countertype 
homopolymers and random copolymers ("Medical Materials and Organism," page 
37 and pages 287 to 289, compiled by Yukio Imanish et al. and published by 
Kodansha Scientific K.K., 1982). In the graft copolymer produced by this 
polymerization of a macromer with other monomer, the graft chain is formed 
not only on the surface of the polymer but in the interior of the polymer. 
The graft copolymer, therefore, has the problem of introducing a change in 
the internal quality of the polymer. 
The method for enhancing the biocompatibility of a medical material by 
physically coating this material on the surface with an oil-soluble 
vitamin has been known to the art (U.S. Pat. No. 4,588,407, for example). 
The medical material having the surface thereof coated with the 
oil-soluble vitamin brings about a secondary effect sparingly on organisms 
and avoids causing any transient decrease in leukocyte. The coating of an 
oil-soluble vitamin deposited only physically on the surface of the 
material, however, exhibits to the substrate material such a weak binding 
force as to entail possible migration of the vitamin into the blood. 
This invention, therefore, has as an object thereof the provision of a 
novel medical material and a method for the production thereof. 
Another object of this invention is to provide a medical material which 
exhibits high biocompatibility stably for a long time and which also 
excels in safety. 
SUMMARY OF THE INVENTION 
The objects described above are accomplished by a medical material produced 
by depositing an oil-soluble vitamin through the medium of a macromer 
containing a hydrophobic moiety on the surface of a substrate formed of a 
functional group-containing polymer. 
The macromer mentioned above is preferable to be bound to the surface of 
the substrate through the medium of a copolymer containing a reactive 
group capable of forming a covalent bond with the functional group of the 
polymer mentioned above. The hydrophobic moiety mentioned above is 
preferable to be selected from the group consisting of a fluorine side 
chain, a silicone side chain, and an alkyl side chain. The average 
molecular weight of the hydrophobic moiety is preferable to be in the 
range of from 100 to 5,000. 
The objects are also accomplished by a method for the production of a 
medical material, which comprises a first step of forming a covalent bond 
between the functional group of a macromer and part of the reactive group 
of a copolymer, a second step of forming a covalent bond between part of 
the reactive group of the copolymer and the functional group of the 
polymer, and a third step of causing an oil-soluble vitamin to contact and 
deposit fast on the hydrophobic moiety of the macromer. 
The objects are further accomplished by a medical apparatus of which at 
least the portions destined to contact blood are formed of the medical 
material set forth in any of the preceding paragraphs describing the 
objects of this invention. 
The objects are further accomplished by a medical material produced by 
causing at least one member selected from the group consisting of higher 
alcohols and higher alcohol macromers to be bound either directly or 
through the medium of a polymer to a substrate. 
Since the medical material of this invention is enabled to retain, in the 
presence of water, an oil-soluble vitamin on the surface of the substrate 
thereof by virtue of a hydrophobic interaction as described above, it is 
capable of manifesting stable biocompatibility and excellent safety for a 
long time without inducing liberation of the oil-soluble vitamin. 
The hydrophobic interaction can also be referred to as a hydrophobic bond 
since the water present in a biological fluid effectively forces the 
hydrophobic groups together. 
When the macromer mentioned above is formed by being bonded to the surface 
of the substrate through the medium of a copolymer containing a reactive 
group capable of forming a covalent bond with the functional group of the 
aforementioned polymer, it can change the surface property of the 
substrate without causing any change in the internal property of the 
substrate because the hydrophobic moiety of the macromer is formed only on 
the surface of the substrate and not in the interior of the polymer. Since 
the macromer allows a multiplicity of oil-soluble vitamins to be retained 
at one point of bonding of the polymer, the medical material is enabled to 
manifest high biocompatibility. 
Further, the medical material of this invention can be stably manufactured 
because it uses a higher alcohol and, as a result, the reaction which 
proceeds during the manufacture does not easily entail a secondary 
reaction or decomposition. Moreover, the activation of the complement 
system is curbed and the substrate is vested with lasting stable 
biocompatibility because a higher alcohol and/or a higher alcohol macromer 
is bound to the substrate directly or through the medium of a polymer.

EXPLANATION OF THE PREFERRED EMBODIMENT 
Now, this invention will be described in detail below. 
The oil-soluble vitamins which are effectively usable in this invention 
include vitamins A, vitamins D, vitamins E, vitamins K, and ubiquinones, 
for example. 
The vitamins A include vitamins A such as retinol (vitamin A.sub.1 
alcohol), retinal (vitamin A.sub.1 aidehyde), vitamin A.sub.1 acid, 
3-dehydroretinol (vitamin A.sub.2 alcohol), and 3-dehydroretinal (vitamin 
A.sub.2 aidehyde) and provitamins A such as beta-carotene (beta, 
beta-carotene), alpha-carotene (beta, epsilon-carotene) and gamma-carotene 
(beta, psi-carotene), for example. 
The vitamins D include vitamins D such as vitamin D.sub.2, vitamin D.sub.3, 
vitamin D.sub.4, vitamin D.sub.5, vitamin D.sub.6, and vitamin D.sub.7 and 
provitamins thereof, for example. 
The vitamins E include tocopherols such as .alpha.-tocopherol, 
.beta.-tocopherol, .gamma.-tocopherol, and .delta.-tocopherol and 
tocotrienols such as .alpha.-tocotrienol, .beta.-tocotrienol, 
.gamma.-tocotrienol, and .delta.-tocotrienol, for example. 
The vitamins K include vitamin K.sub.1 and vitamins K.sub.2, for example. 
The ubiquinones include ubiquinone-1 to ubiquinole-12 (Q-1 to Q-12) and the 
oxidized forms thereof and amino chloride compounds thereof, for example. 
The medical material of this invention is characterized by having such an 
oil-soluble vitamin deposited through the medium of a macromer containing 
a hydrophobic moiety on the surface of a substrate formed of a functional 
group-containing polymer. 
In the medical material of this invention, the polymer of which the 
substrate is formed has no particular restriction except for the sole 
requirement that it should possess repeating units containing a functional 
group. The functional groups which the repeating unit are allowed to 
contain include hydroxyl group, amino group, carboxyl group, epoxy group, 
and aidehyde group, for example. As polymers possessing a hydroxyl group 
as the functional group, regenerated cellulose and cellulose derivatives 
may be cited. In the unit of regenerated cellulose shown below, for 
example, the hydroxyl group indicated by an asterisk (*) is a functional 
group. Incidentally, the hydroxyl group not indicated by an asterisk (*) 
and attached to the 3 position possesses poor reactivity from the 
standpoint of the construction of cellulose. 
##STR1## 
The other polymers which are effectively usable herein include polyvinyl 
alcohol, partially saponified polyvinyl acetate, ethylene-vinyl alcohol 
copolymers, partially saponified ethylene-vinyl acetate polymers, 
polyacrylic acid and polymethacrylic acid and copolymers thereof, 
polyhydroxy methacrylate, chitin, chitosan, collagen, and polyacrylamide, 
for example. The term "macromer" as used in this invention refers to a 
macromolecular compound containing a reactive functional group. 
The hydrophobic moiety has no particular restriction except for the 
requirement that it should be capable of retaining the oil-soluble vitamin 
by a hydrophobic interaction. The hydrophobic moieties which are usable 
herein include a fluorine type side chain such as of perfluoroalcohol, a 
silicone type side chain such as of polydimethyl siloxane derivative, 
fatty acids, fatty acid derivatives, higher alcohols, and alkyl type side 
chains such as of higher alcohol derivatives, for example. The average 
molecular weight of this hydrophobic side chain is desired to be in the 
range of from 100 to 5,000. If the average molecular weight is less than 
100, the oil-soluble vitamin cannot be retained with sufficient fastness. 
Conversely, if the average degree of polymerization exceeds 5,000, the 
hydrophobic moiety has the possibility of altering the nature of the 
polymer itself of the substrate. 
The macromer containing the hydrophobic moiety of the nature described 
above is caused to assume a flexible linear structure containing neither a 
cyclic structure nor a triple bond. Owing to the assumption of this 
particular structure, the macromer is enabled to be bound in an amply 
mobile and stable state to the surface of the substrate. 
Preferably, the macromer containing the hydrophobic moiety is bound through 
the medium of a spacer to the copolymer which will be described more 
specifically hereinbelow. 
The spacers which are effectively usable herein include alkylene glycol 
diamines such as polyethylene glycol diamine, polypropylene glycol 
diamine, and polytetramethylene glycol diamine, for example. 
The average degree of polymerization of the alkylene glycol diamine is 
preferable to be approximately in the range of from 1 to 100, though it is 
variable with the kind of the alkylene. 
In this invention, the macromer containing the hydrophobic moiety 
(hereinafter the "macromer" will be occasionally construed in a broad 
sense of the word such as to embrace the spacer) is preferable to be 
formed by being bound to the surface of the substrate through the medium 
of a copolymer containing a reactive group capable of forming a covalent 
bond with the functional group of the polymer of which the substrate is 
formed. 
The copolymer serving as the medium has no particular restriction except 
for the requirement that it should contain a reactive group capable of 
forming a covalent bond with the functional group of the polymer as 
described above. As the reactive group, the copolymer is an epoxy group, a 
carboxyl group, a group of the ester thereof, and/or an aidehyde group. 
The copolymer and the hydrophobic moiety mentioned above can be bound to 
each other by graft copolymerizing the hydrophobic moiety through the 
medium of the epoxy group of the copolymer, for example. 
The monomer as the raw material for the copolymer containing an epoxy group 
is preferable to be the glycidyl ester of a (meth)acrylic acid. The 
monomer as the raw material for the copolymer containing a carboxyl group 
is preferable to be a (meth)acrylic acid. The raw materials which are 
effectively usable as the raw material for the copolymer include esters 
such as (meth)acrylic esters represented by methyl (meth)acrylates, ethyl 
(meth)acrylates, propyl (meth)acrylates, isopropyl (meth)acrylates, butyl 
(meth)acrylates, isobutyl (meth)acrylates, hydroxyethyl (meth)acrylates, 
and mixtures thereof, for example. 
The use of a polymerization initiator such as, for example, ammonium eerie 
nitrate or ferrous salt of hydrogen peroxide suffices to produce the 
copolymer from the aforementioned monomer. The weight ratio of the epoxy 
group-containing monomer to the copolymer preferably ranges from 0.01 to 
60% by weight, preferably from 1 to 10% by weight. 
The average molecular weight of the copolymer is preferably approximately 
in the range of from 500 to 500,000, preferably from 5,000 to 100,000. 
In this invention, the amount of the macromet and that of the oil-soluble 
vitamin relative to the amount of the substrate are preferably 
respectively in the range of from 1 to 200 parts by weight and range of 
from 1 to 1900 parts by weight, preferably in the range of from 20 to 150 
parts by weight and the range of from 50 to 500 parts by weight, based on 
100 parts by weight of the substrate. 
Now, the method for the production of the medical material of this 
invention will be described below. 
To be specific, the method for the production of the medical material of 
this invention is characterized by comprising a first step of forming a 
covalent bond between the functional group of a macromer and part of the 
reactive group of the copolymer, a second step of forming a covalent bond 
between part of the reactive group of the copolymer and the functional 
group of the polymer, and a third step of causing an oil-soluble vitamin 
to contact and deposit fast on the hydrophobic moiety of the macromer. 
For example, the copolymer is dissolved in a solvent containing acetone, 
carbon tetrachloride and acetonitrile at room temperature, a dehydrating 
condensing agent such as N, N'-dicyclohexylcarbodiimide (1.2 mol per 1 mol 
of a carboxyl group of the copolymer) is added at a room temperature, the 
macromer 0.25 mol of an amino group of the macromer per 1 mol of a 
carboxyl group of the copolymer) is added, and is maintained at a 
temperature of 80.degree. C. for 30 minutes. Then in order to remove an 
unnecessary component (in such case, it is N, N'-dicyclohexyl urea), the 
mixture is cooled in an iced water for 30 minutes to precipitate and the 
precipitate is filtered off. Then in order to remove an unreacted 
macromer, water (10 times of the solvent) is added to the filtrate because 
the unreacted macromer dissolves in water and is subjected to 
centrifugation at 10,000 r.p.m. for 5 minutes. 
The covalent bond between the functional group of the macromer and the 
reactive group of the copolymer can be formed by any of the known methods 
available for this purpose. 
The formation of a covalent bond between the polymer forming the substrate 
and the product of union of the macromer and the copolymer obtained by the 
method described above (hereinafter referred to as a "macromolecular 
derivative") is effected by dissolving the macromolecular derivative in a 
suitable organic solvent, adding a Lewis acid catalyst and/or a basic 
catalyst to the resultant solution, and establishing contact between the 
polymer and the macromolecular derivative as by immersing the polymer in 
the solution. The amount of the catalyst is in the range of from 0.01 to 
20% by weight, preferably from 0.5 to 5% by weight. The temperature of the 
reaction is in the range of from 10.degree. to 300.degree. C., preferably 
20.degree. to 150.degree. C. 
The Lewis acid catalysts which are effectively usable herein include boron 
trifluoride, tin tetrachloride, and zinc chloride, for example. The basic 
catalysts which are effectively usable herein include hydroxides of 
alkaline earth metals, particularly calcium, strontium, barium, and radium 
and hydroxides of alkali metals such as lithium hydroxide, potassium 
hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide, 
for example. 
The organic solvents which are effectively usable herein include dioxane, 
acetone, diethyl ketone, methy ethyl ketone, ethyl acetate, isoamyl 
acetate, tetrahydrazine, and the like. The concentration of the 
macromolecular derivative in the solution is in the range of from 0.01 to 
40% by weight, preferably from 0.1 to 10% by weight. 
Then, the solution of an oil-soluble vitamin in an organic solvent is 
brought into contact with the resultant modified polymer. The 
concentration of the oil-soluble vitamin solution to be used is 
approximately in the range of from 0.05 to 20 w/v %, preferably from 0.5 
to 5 w/v %. The time of contact of the solution to the modified polymer is 
approximately in the range of from 30 seconds to 60 minutes, preferably 
from 30 seconds to 5 minutes. After this contact is completed, the 
retention of the oil-soluble vitamin to the modified polymer is attained 
by introducing an inert gas to the oil-soluble vitamin at a temperature in 
the range of from 10.degree. to 80.degree. C. preferably from 15.degree. 
to 25.degree. C. thereby expelling the organic solvent. The organic 
solvents which are effectively usable herein include alcohols such as 
methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol, 
ethers such as diethyl ether and tetrahydrofuran, and Freon solvents such 
as 1,1,2-trichloro-1,2,2-trifluoroethane, for example. The medical 
material consequently produced is sterilized by the treatment with an 
autoclave, ethylene oxide, gamma ray, for example, before it is put to 
actual use. 
Now, the medical apparatus of this invention will be described below. 
To be specific, the medical apparatus of this invention is constructed so 
that at least the portions thereof destined to contact blood are formed of 
the medical material described above. As typical examples of the medical 
apparatus, extracorporeal circulation systems such as artificial lung 
circuit systems, artificial dialysis systems, blood plasma separation 
systems, and various catheters and artificial organs such as artificial 
blood vessels which are buried in human bodies may be cited. The medical 
apparatus of this invention precludes the liberation of the oil-soluble 
vitamin for a long time and manifests stable biocompatibility and 
excellent safety because at least the portions of the apparatus destined 
to contact blood are formed of the medical material described above. 
Further, since the medical apparatus of this invention is so constructed 
that a higher alcohol and/or a higher alcohol macromer is bound directly 
or through the medium of a polymer to the substrate, it enjoys prominent 
biocompatibility originating in the higher alcohol. Since the hydroxyl 
group of the higher alcohol reacts with the functional group of the 
substrate or the polymer to give rise to an ether bond therebetween, the 
bond in the medical apparatus is stronger than the ester bond resulting 
from the reaction of the carboxyl group as the reactive terminal of a 
fatty acid with the functional group of the substrate or the polymer. This 
fact explains why the medical apparatus of this invention exhibits lasting 
stable biocompatibility without entailing liberation of the higher 
alcohol. 
The hydroxyl group of a higher alcohol is used for the production of a 
higher alcohol macromer, the bond can be easily formed by the addition 
polymerization of a molecular chain (spacer) under the conditions 
incapable of readily inducing a secondary reaction. 
The use of a higher alcohol macromer enables the medical apparatus to curb 
the adhesion of blood platelets by virtue of the interposition of a 
molecular chain (spacer) between the higher alcohol and the substrate or 
the polymer, acquire high biocompatibility, obtain easy control of the 
molecular chain length, and ensure stable mobility of the molecular chain. 
The higher alcohol in this invention is preferable to be a monohydric 
alcohol from the standpoint of adjustment of the molecular chain and 
manufacture of the medical material. The alcohol is preferable to be in an 
unsaturated form in point of resistance to thrombosis. To be specific, the 
higher alcohols having 4-30 carbon atoms, preferably 10-20 carbon atoms 
which are effectively usable herein include oleyl alcohol, lauryl alcohol, 
myristyl alcohol, cetyl alcohol, and stearyl alcohol, for example. Among 
other alcohols, oleyl alcohol proves to be particularly desirable in point 
of compatibility for blood. 
In this invention, for the purpose of enhancing the biocompatibility, 
particularly the adaptability for blood, the higher alcohol may be bound 
in the form of a higher alcohol macromer preferably through the medium of 
a hydrophilic spacer. 
As a typical spacer, an alkylene glycol having highly reactive functional 
groups attached one each to the opposite terminals thereof may be cited. 
The alkylene glycols which answer this description include polyethylene 
glycol diamine, polypropylene glycol diamine, and polytetramethylene 
glycol diamine, for example. 
When the spacer to be used has an alkylene glycol sheleton, for example, 
the degree of polymerization thereof is preferable to be approximately in 
the range of from 1 to 100, though variable with the kind of the alkylene. 
Among other alkylene glycols mentioned above, polyethylene glycol and 
polypropylene glycol prove to be preferable. It is particularly preferable 
to use polyethylene glycol having a degree of polymerization in the range 
of from 20 to 90 or polypropylene glycol having a degree of polymerization 
in the range of from 10 to 50. 
The polymer for this invention is as already described. 
The substrate is used in any of various forms such as, for example, a 
sheet, a tube (inclusive of a hollow fiber), and fibers. 
Though the method to be employed for the production of the medical material 
of this invention is not particularly restricted, the following method can 
be used preferably. Specifically, this method comprises a step of forming 
a covalent bond between the functional group of a higher alcohol and/or a 
higher alcohol macromer and part of the functional group of a polymer and 
a step of forming a covalent bond between part of the functional group of 
the polymer and the functional group of the substrate. These steps may be 
carried out either simultaneously or sequentially in any desired order. 
When a higher alcohol and/or a higher alcohol macromer containing amino 
groups at the opposite terminals, for example, a polymer containing an 
epoxy group and the higher alcohol macromer form a graft copolymer through 
the medium of the epoxy group contained in the polymer or a copolymer 
containing an epoxy group and a carboxyl group and a higher alcohol and/or 
a higher alcohol macromet form a macromolecular derivative in the form of 
a graft copolymer through the medium of the carboxyl group of the polymer. 
For the reaction resulting in the formation of the graft copolymer, any of 
the known conventional methods of synthesis can be used. 
Now, this invention will be described more specifically below with 
reference to working examples. 
EXAMPLE 1 
(1) Synthesis of linolic acid macromer 
A solution of 20.0 g of linolic acid in 70 ml of dry benzene was placed in 
a flask and kept swept therein with nitrogen for displacement of the 
entrapped air and 14.8 g of phosphorus pentachloride was added meanwhile 
thereto as divided in five split portions. The resultant reaction mixture 
was stirred at normal room temperature for 12 hours and then refluxed for 
two hours. Then, the reaction solution was distilled to expel benzene and 
the products of a secondary reaction, i.e. phosphoryl trichloride and 
hydrogen chloride and the residue was subjected to vacuum distillation to 
produce 14.0 g of linolic acid chloride (boiling point 155.degree. C./1.5 
mmHg; yield 76%). 
In a flasks 50.4 g of polyethylene glycol diamine (a product of a molecular 
weight of 4,114; marketed by Toray Ltd. under product code of "PGD-40"), 
1.48 g of triethyl amine, and 120 ml of dichloromethane were placed and 
kept swept with nitrogen and a solution of 3.66 g of linolic acid chloride 
in 70 ml of dichloromethane was added dropwise thereto over a period of 30 
minutes. Then, the reaction mixture was left gradually warming to normal 
room temperature and, at the same times stirred for two hours. The 
resultant reaction solution was filtered to remove triethyl amine as the 
product of a secondary reaction and subjected to vacuum distillation to 
expel triethyl amine and dichloromethane. The residue was dissolved in 100 
ml of chloroform and washed gently with 100 ml of water. The organic layer 
consequently formed was separated, dried with anhydrous soidum sulfate, 
and concentrated. When the concentrate was purified by flush 
chromatography (decomposing solution: chloroform/methanol V/V) using Wako 
C-300, 13.7 g of a purified product (macromet of linolic acid) was 
obtained (yield 26%). 
The structure of the purified product was identified by the IR method and 
the .sup.1 H-NMR method and the perfect absence of linolic acid and PGD-40 
from the purified product was confirmed by liquid chromatography (GPC 
modes dissolving solution THF). 
The results of the tests described above are shown below. 
IR method: 
1650 cm.sup.-1 - expansive motion of amide carbonyl 
1540 cm.sup.-1 - angular motion of amide NH 
1100 cm.sup.-1 - expansive motion of ether 
.sup.1 H-NMR method: 
.delta.0.3 ppm - linolic acid - CH.sub.3 
.delta.1.3 ppm - linolic acid - CH.sub.2 -- 
.delta.3.7 ppm - polyethylene glycol - OCH.sub.2 CH.sub.2 O 
.delta.5.3 ppm - olefin linolate - CH.dbd.CH-- 
GPC method: 
Volume of purified product retained 11.4 ml 
PGD-40 12.6 ml 
Linolic acid 15.1 ml 
(2) Synthesis of copolymer 
A polymerization tube made of glass was charged with 0.15 part by weight of 
azo-bis-isobutylonitrile as a polymerization initiator, 7.5 parts by 
weight of methyl methacrylate, 15 parts by weight of glycidyl 
methacrylate, 6 parts by weight of 3-methacryloxypropyl 
tris(methoxyethoxy)silane (produced by Chisso Corp.), and 1.5 parts by 
weight of methacrylic acid. The polymerization tube was cooled and 
solidified in liquefied nitrogen, alternately evacuated of air and 
displaced with nitrogen repeatedly, and then sealed tightly. The sealed 
tube containing the reaction mixture was heated in a constant temperature 
bath at 60.degree. C. for 50 minutes. Thereafter, the tube was cooled and 
opened. The content was dissolved in THF and reprecipitated with methanol, 
to obtain a white copolymer. 
The copolymer was dissolved in methylethyl ketone and titrated with a 0.01N 
perchloric acid/acetic acid solution using triethyl trimethyl ammonium 
bromide as a catalyst and crystal violet as an indicator to determine an 
epoxy equivalent and find the composition of glycidyl methacrylate. The 
yield was found to be 52.9% by weight. 
(3) Reaction of linolic acid macromer with copolymer 
In a flask, 4.00 g of the copolymer obtained in (2), 0.718 g of 
dicyclohexyl carbodiimide, and 100 ml of a mixed solvent of carbon 
tetrachloride/acetonitrile (1:1 v/v) were placed, stirred at normal room 
temperature for 60 minutes as kept swept with nitrogen and, after thorough 
solution, a solution of 12.0 g of the linolic acid macromer obtained in 
(1) in 20 ml of carbon tetrachloride/acetonitrile (1:1 v/v) was gradually 
added dropwise thereto. Then, the resultant mixture was stirred at normal 
room temperature for 60 minutes and further stirred at 60.degree. C. for 
60 minutes. The reaction product was cooled to normal room temperature. 
The content of the flask was passed through a glass filter. When the 
filtrate was gently distilled to expel the solvent, there was obtained a 
yellow highly viscous crude product. 
The crude product and 200 ml of methanol added thereto were stirred at 
normal room temperature for about 30 minutes, and subjected to centrifugal 
separation. The supernatant was removed by decantation. The procedure was 
repeated twice more. When the final residue was subjected to vacuum 
drying, there was obtained 9.63 g of a macromolecular derivative. 
(4) Graft polymerization of macromolecular derivative to regenerated 
cellulose 
In 100 ml of an aqueous 0.3 (w/v) % sodium hydroxide solution, 300 
regenerated cellulose membranes (0.2 mm in thickness) were immersed for 30 
minutes. Then, the regenerated cellulose membranes were immersed in an 
aqueous acetone solution containing the macromolecular derivative obtained 
in (3) in a concentration of 0.5 (w/v) and left reacting therein at normal 
room temperature for 24 hours. 
After the reaction was completed, the regenerated cellulose membranes were 
removed from the aqueous solution, washed with acetone, ethanol, and 
distilled water sequentially in the order mentioned, to produce 
regenerated cellulose membranes A having the macromolecular derivative 
graft polymerized to the surface thereof. 
(5) Preparation of dialyzer using regenerated cellulose membranes 
A hollow fiber bundle 5 was formed of 340 hollow fibers of regenerated 
cellulose of cuprammonium measuring about 200 .mu.m in inside diameter, 
about 224 .mu.m in outside diameter, and 14 cm in available length and 
obtained in (4). The hollow fiber bundle 5 was inserted in a cylinder 
proper 4 as illustrated in FIG. 1 and the opposite ends of the hollow 
fiber bundle were immobilized in place with discs 6, 7 of a polyurethane 
type potting agent. Headers 10, 11 were attached to the opposite ends and 
fixed with caps 12, 13, to complete a dialyzer (artificial kidney) 1. The 
membranes had an inside surface of 300 cm.sup.2. In the dialyzer 
illustrated in FIG. 1, a cylindrical body 4 was provided near the opposite 
terminal parts thereof with an inlet tube 2 and an outlet tube 3 for 
passage of a fluid for dialysis. 
(6) Deposition of vitamin E on regenerated cellulose membrane 
A 1,1,2-trichloro-1,2,2-trifluoroethane solution of vitamin E was prepared 
by dissolving 5.0 g of vitamin E (-tocopherol) in 100 ml of 
1,1,2-trichloro-1,2,2-trifluoroethane. A syringe was connected to one end 
of the dialyzer and the other end of the dialyzer was susbmerged in the 
vitamin E solution. The plunger of this syringe was operated to introduce 
the vitamin E solution into the dialyzer to capacity. Then, the dialyzer 
was pulled out of the vitamin E solution, emptied of the vitamin E 
solution, and dried by means of an aspirator capable of supplying a 
current of air at 25.degree. C. It was further left standing in an oven at 
60.degree. C. for one hour. It was subsequently treated in an autoclave at 
115.degree. C. for 30 minutes to complete a dialyzer A of this invention. 
Control 
A dialyzer B for comparison was prepared by following the procedure of 
Example, excepting a cellulose membrane B which had undergone a treatment 
for coating with vitamin E and none of the treatments (1) to (4) mentioned 
above was used instead as a regenerated cellulose membrane. 
Test for extracorporeal circulation 
The dialyzers A and B and a dialyzer C packed with untreated regenerated 
cellulose were tested for performance in extracorporeal circulation. 
A rabbit was fastened as laid on the back to a Kitajima's stationary bed. 
Then, the hair in the region selected for surgery was clipped with an 
electric clipper and thoroughly wiped with a wad impregnated with alcohol. 
The throat was cut open along the median line from below the jaw through 
the clavicle with a scissors, the fascia consequently exposed was opened, 
and the right (left) catroic artery and then the left (right) facial vein 
were excoriated advertently so as to avoid injuring the nerve, the 
branched blood vessel, and the neighboring tissue. An indwelling catheter 
(produced by Terumo K.K.) filled with a 1 IU/ml heparin-added 
physiological saline solution and stoppered with a mixture-dispensing 
rubber cap was inserted into the artery mentioned above and tied thereto. 
A similar catheter was inserted in the vein mentioned above and tied 
thereto. An experimental circuit incorporating therein a given dialyzer, A 
to C, was laid through the rabbit 20 prepared as described above. To be 
specific, a catheter 21 connected to the artery of the rabbit 20 was 
connected on the free end to a pump 22 and a chamber 23 and the vein of 
the rabbit 20 were interconnected through the medium of a catheter 25. The 
pump 22 and the dialyzer 1 were interconnected through the medium of a 
tube 26, which was connected to an in 27 side of a manometer. Further, the 
dialyzer 1 and the chamber 23 connected to an out 24 side of the manometer 
were interconnected through the medium of a tube 28. The inlet and the 
outlet of the dialyzer for passage of the fluid for dialysis were 
interconnected through the medium of a tube 29, which was furnished with a 
pump 30 and immersed in a water bath kept at 37.degree. C. 
The circuit so constructed was cleaned by being primed with 100 ml of 1 
IU/ml heparin-added physiological saline solution. The extracorporeal 
circulation of blood was carried out at a rate of 10 ml/min. Absolutely no 
anticoagulant was used in the blood in circulation. The blood in 
circulation was sampled in a fixed size of 1 ml after the intervals of 5, 
10, 15, 20, 30, 45, 60, and 120 minutes following the start of the 
circulation. Each sample was treated with a 1.5% EDTA-2Na physiological 
saline solution to be proofed against coagulation and then analyzed with 
an ELT-8 (produced by Orth Instument Corp.) to find the number of blood 
cells. 
The data consequently obtained concerning the count of white blood cells 
(WBC), the count of blood platelets (PLT), and the hematocrit value (HCT) 
are shown in Tables 1 to 3. Specifically, Table 1 shows the data on the 
experimental circuit using the dialyzer A, Table 2 the data on the 
experimental circuit using the dialyzer B, and Table 3 the data on the 
experimental circuit using the dialyzer C. The count of blood platelets 
was subjected to Ht value correction in accordance with the following 
numerical expression and reported in the magnitude of Ht value found 
immediately before the start of circulation. 
EQU i Cx=Co.times.Htx/Hto 
wherein Cx is a corrected value, Co is a found value, Htx is an initial Ht 
value, and Hto is a Ht value existing at the time the Co value was 
obtained. 
The amounts of vitamin E retained initially on the regenerated celluloses A 
and B were determined by the HPLC analysis. The conditions for the HPLC 
analysis were as shown in Table 4. The amount of vitamin E eluted in the 
circulating blood was determined by sampling 1 ml of the circulating blood 
plasma, mixing the sample with 1 ml of ethanol for 30 seconds, then mixing 
the resultant mixture with 5 ml of hexane for one minute, and centrifuging 
the final mixture at a rate of 1,500 rpm for five minutes thereby 
separating and extracting the vitamin E emanating from the sample. The 
ratio of vitamin E elution (=(Amount of eluted vitamin E/Amount of vitamin 
E initially deposited) .times.100) was calculated by the use of the found 
values. 
TABLE 1 
______________________________________ 
WBC PLT HCT Ratio of vita- 
Time PIC .times.10.sup.4 
PIC PIC min E elution 
min /mm.sup.3 
(%) /mm.sup.3 
(%) % (%) wt % 
______________________________________ 
Initial 
29.2 100 31.8 100 39.7 100 0 
5 24.5 83.5 25.9 81.0 39.9 100.5 
10 24.8 85.2 25.9 81.7 39.6 99.7 
15 28.5 98.1 25.9 81.9 39.5 99.5 
20 29.0 102.2 25.2 81.5 38.6 97.2 
30 30.2 107.2 24.4 79.5 38.3 96.5 0.1 
45 33.0 122.6 22.0 75.0 36.6 92.2 
60 35.3 132.3 22.7 78.1 36.3 91.4 0.5 
120 40.7 153.3 21.8 75.4 36.1 90.9 0.5 
______________________________________ 
TABLE 2 
______________________________________ 
WBC PLT HCT Ratio of vita- 
Time PIC .times.10.sup.4 / 
PIC PIC min E elution 
min /mm.sup.3 
(%) mm.sup.3 
(%) % (%) wt % 
______________________________________ 
Initial 
6200 100 61.3 100 43.3 100 0 
5 5710 92.1 57.3 93.5 39.4 91.0 
10 4030 90.5 56.3 91.8 39.9 92.1 
15 4220 75.2 54.8 89.4 39.2 90.5 
20 5200 83.9 53.4 87.1 39.1 90.3 
30 5140 84.5 50.6 82.5 39.7 91.7 80.0 
45 5450 96.4 46.7 76.1 39.5 91.2 
60 5930 106.7 46.1 75.2 38.8 89.6 86.0 
120 7380 119.0 42.4 69.2 39.3 90.7 89.0 
______________________________________ 
TABLE 3 
______________________________________ 
WBC PLT HCT Ratio of vita- 
Time PIC .times.10.sup.4 
PIC PIC min E elution 
min /mm.sup.3 
(%) /mm.sup.3 
(%) % (%) wt % 
______________________________________ 
Initial 
8100 100 86.4 100 44.4 100 
5 4230 52.2 79.8 92.4 39.3 89.9 
10 3850 47.5 76.8 88.9 39.2 88.3 
15 4100 50.6 73.2 84.7 41.2 92.8 
20 4520 55.8 71.4 82.6 40.3 90.8 
30 6820 84.2 59.8 78.0 39.4 86.5 
45 6870 84.8 66.7 77.2 38.9 87.6 
60 8790 108.5 44.8 59.2 38.9 87.6 
120 11250 142.2 42.7 55.0 39.7 89.4 
______________________________________ 
TABLE 4 
______________________________________ 
Apparatus: Twincle (manufactured by Nippon 
Bunko K.K.) 
Column: Toso-TSK Gel Amido-80 4.6 .times. 25 mm 
Moving bed: 
n-hexane: isopropanol (95:5) mixed solution 
Rate: 1.5 ml/min 
Determination: 
UY monitor 292 nm 
Pressure: 75 kg/cm.sup.2 
Sample solution: 
ethanol solution 
Injection amount: 
10 .mu.l 
______________________________________ 
It is clearly noted from Tables 1 to 3 that the dialyzer A embodying this 
invention manifested stable biocompatibility as evinced by only a small 
elution of the vitamin E in the circulating blood because the vitamin E 
was deposited through the medium of a macromer possessed of a hydrophobic 
moiety, whereas the dialyzer B embodying the conventional technique showed 
gradual decline of bioadaptability with the elapse of time because the 
vitamin E was physically deposited simply in the foam of a coating and, 
therefore, was highly susceptible of elution. 
EXAMPLE 2 
(1) Synthesis of oleyl alcohol macromer 
In 50 ml of dioxane, 20.00 g of polyethylene glycol monooleyl ether 
(average molecular weight 4,268) obtained by addition of ethylene oxide to 
an oleyl alcohol in the presence of an alkali catalyst and 1.90 g of 
triethyl amine were dissolved. The resultant solution and a solution of 
1.85 g of p-toluenesulfonyl chloride in 10 ml of dioxane slowly added 
dropwise thereto were left reacting at 60.degree. C. for two hours. The 
reaction product was refined by being dissolved with 200 ml of acetone 
added thereto, then cooled to 0.degree. C., and left standing to allow 
sedimentation of the product aimed at. Then, a solution of 6.50 g of the 
product mentioned above in 30 ml of DMF and 0.55 g of potassium 
phthalimide added thereto were left reacting at 90.degree. C. for two 
hours. The reaction product was refined by being dissolved with 60 ml of 
acetone added thereto, then cooled to 0.degree. C., and left standing to 
allow sedimentation of the product aimed at. Subsequently, a solution of 
6.00 g of the product mentioned above in 30 ml of ethanol and 1.00 g of 
hydrazinc hydrate added thereto were left reacting as refluxed for two 
hours. The reaction product was refined by being dissolved with 60 ml of 
acetone added thereto, then cooled to 0.degree. C., and left standing to 
allow sedimentation of the product aimed at. Consequently, 5.20 g of an 
oleyl alcohol macromer possessed of amino groups at the terminals thereof 
was obtained. 
(2) Synthesis of copolymer 
A polymerization tube made of glass was charged with 0.15 part by weight of 
azo-bis-isobutylonitrile as a catalyst, 7.5 part by weight of methyl 
methacrylate, 15 parts by weight of glycidyl methacrylate, 6 parts by 
weight of 3-methaeryloxypropyl tris(methoxyethoxy) silane (produced by 
Chisso Corporation), and 1.5 parts by weight of methacrylic acid, cooled 
and solidified with liquefied nitrogen, alternately subjected to 
evacuation of air by a vacuum pump and displacement of the entrapped air 
with nitrogen repeatedly, and thereafter sealed tightly. In a constant 
temperature bath, the polymerization tube was heated at a prescribed 
temperature for a prescribed time. It was cooled and opened to remove the 
content. The polymerization mixture was dissolved in tetrahydrofuran and 
reprecipitated in methanol. Consequently, a white polymer was obtained. 
Similarly, a copolymer containing no methacrylic acid was synthesized. 
The copolymer was dissolved in methylethyl ketone. The solution was 
titrated with a 0.01N perchloric acid/acetic solution in the presence of 
ethyl bromide trimethyl ammonium as a catalyst and crystal violet as an 
indicator to find an epoxy equivalent and the composition of glycidyl 
methacrylate (Table 5). 
TABLE 5 
______________________________________ 
Poly- Poly- Content of 
merization merization 
glycidyl 
Charged 
Copolymer Temperature 
time methacrylate 
monomer 
Nov. (.degree.C.) 
(min) (wt %) 
______________________________________ 
A 1 60 50 52.9 
B 2 60 50 52.7 
______________________________________ 
A: MMA/GMA/MPTMS/MA = 7.5/15/6/1.5 (wt. ratio) 
B: MMA/GMA/MPTMS = 7.5/15/7.5 (wt. ratio) 
MMA: methyl methacrylate 
GMA: glycidyl methacrylate 
MPTMS: 3methacryloxypropyltris (methoxyethoxy) silane 
MA: methacrylic acid 
(3) Reaction of oleyl alcohol macromer with copolymer 
In a flask, 4.00 g of the aforementioned copolymer No. 1, 0.718 g of 
dicyclohexylcarbodiimide, and 100 ml of a mixed solvent of carbon 
tetrachloride/acetonitril (1:1 by volume) were stirred as kept swept with 
nitrogen for 60 minutes. The resultant solution and a solution of 9.92 g 
of the oleyl alcohol macromer in 20 ml of carbon 
tetrachloride/acetonitrile (1:1 by volume) gradually added dropwise 
thereto were stirred at room temperature for 60 minutes and further 
stirred at 60.degree. C. for 60 minutes. The content of the flask was 
cooled to normal room temperature and then passed through a glass filter. 
When the filtrate was distilled gently to expel the solvent by 
evaporation, there was obtained a yellow highly viscous crude product. 
The crude product and 200 ml of methanol added thereto were stirred at 
normal room temperature for about 30 minutes untillumps ceased to exist. 
The resultant solution was centrifuged and the supernatant was removed by 
decantation. This procedure was repeated twice more. The final residue was 
dried under a vacuum, to produce 8.75 g of a macromolecular derivative. 
(4) Bonding of macromolecular derivative to regenerated cellulose membrane 
The macromolecular derivative was bonded to the surface of regenerated 
cellulose as follows. 
First, 0.3 g of regenerated cellulose membrane (0.2 mm in membrane 
thickness) was kept immersed in 100 mm of an aqueous 0.5 (W/V) % sodium 
hydroxide solution for 30 minutes. Then, the cellulose membrane was 
immersed in an acetone solution of 0.5 (W/V) % of the macromolecular 
derivative and left reacting therein at normal room temperature for 24 
hours. After the reaction was completed, the regenerated cellulose 
membrane was taken out of the solution and thoroughly washed with acetone, 
ethanol, and distilled water sequentially in the order mentioned, to 
obtain a sample 1 of the medical material embodying this invention. 
Controls 2 and 3 
A mixture of 0.04 g of pyridine with 30 ml of dry dioxane was prepared. 
Then, 0.90 g of linolic acid was introduced by the use of this mixture 
into a flask. The resultant mixture in the flask was stirred as kept swept 
with nitrogen at 80.degree. C. for 30 minutes. The content of the flask 
and a solution of 3.00 g of the copolymer No. 2 in 70 ml of dry dioxane 
added thereto were stirred at 80.degree. C. for six hours. The resultant 
reaction mixture was cooled to normal room temperature and subjected to 
gentle distillation to expel the solvent by evaporation. Consequently, a 
light brown highly viscous crude product was obtained. The crude product 
and 100 mm of methanol added thereto were stirred at normal room 
temperature for about 30 minutes (until lumps ceased to exist) and 
subjected to centrifugal separation. The supernatant was removed by 
decantation. When this procedure was repeated twice more and the final 
residue was subjected to vacuum drying, 3.05 g of a macromolecular 
derivative was obtained. A sample 2 (Control 2) was obtained by bonding 
the macromolecular derivative to regenerated cellulose membrane by 
following the procedure of Example. 
A regenerated cellulose membrane was used as Sample 3 (Control 3). 
Evaluation Test 1 
The samples of Example 2 and Controls 2 and 3 were tested for change of 
correction value in accordance with the original Mayer method indicated 
below. The results of the test are shown in Table 6. 
Each sample was preparatorily brought to an equilibrium state of sorption 
by immersion in physiological saline solution. The sample was gently wiped 
to remove water from the surface and trimmed into a small piece 20 
cm.sup.2 in surface area. The cut sample was placed in a plastic blood 
collecting tube and 1 ml of the serum extracted from an adult dog was 
automatically added to the cut sample in the tube. The contents of the 
tube were kept at 370.degree. C. for three hours to activate the cut 
sample to determine the change in the correction value CH50 (correction 
value determined by the 50% hemolysis method) and calculate the ratio of 
consumption. 
TABLE 6 
______________________________________ 
Sample Consumption rate of CH50 
______________________________________ 
Example 2 (Sample 1) 
13.5 
Control 2 (Sample 2) 
14.2 
Control 3 (Sample 3) 
35.7 
______________________________________ 
It is clearly noted from Table 6 that the medical material of this 
invention brings about a very small decrease of the correction value CH50 
in the serum as compared with the untreated sample. 
Evaluation Test 2 
By the use of a polypropylene syringe preparatorily containing an aqueous 
3.8% sodium citrate solution (1/9 of the volume of the blood to be 
subsequently collected), the venous blood of a healthy man was extracted. 
The blood was transferred into a polypropylene test tube by causing it to 
flow gently down on the inner wall of the test tube and then centrifuged 
at 800 r.p.m. for five minutes. The platelet rich blood plasma (PRP) in 
the supernatant was collected and diluted with a dilute aqueous 3.8% 
sodium citrate solution (1/10 of the volume of a lactic acid Ringer's 
solution) to prepare a platelet suspension. This plate suspension was 
found to contains 66,000 platelets per mm.sup.2. On each sample (1 
cm.sup.2) from Example 1 and Controls 2 and 3, 0.2 ml of the platelet 
suspension was placed in a thickness of 2 mm and brought into contact at 
normal room temperature for 30 minutes. After the elapse of a prescribed 
time, the sample was gently washed with a dilute 3.8 % sodium citrate 
solution. Then, the sample was placed in a 2.5% glutar aidehyde/lactic 
acid Ringer's solution and left standing overnight in a cool place to be 
fixed. The fixed sample was gently washed with a dilute 3.8% sodium 
citrate solution, subjected to stepped dehydration with an ethanol series 
(sequential 10 minutes treatment in ethanol solutions having ethanol 
contents of 50%, 60%, 70%, 80%, 90%, 95%, 100%, and 100%), dried with a 
current of air, and observed under a scanning electron microscope 
(produced by Nippon Denshi K.K. and marketed under product code of 
"JSM-840"). The evaluation was made on the basis of the number of 
platelets adhering to a sample area of 0.07 mm.sup.2 and the change in 
form. The change in form was classified under the following three types. 
Type I: The platelets transformed from their normal shape of discs into 
spheres with three to four protruding pseudopodia and suspected to be 
bound relatively weakly to the surface of a given sample. 
Type II: The platelets transformed to the extent of protruding more than 
several pseudopodia and expanding cells to half the size of pseudopodia 
and suspected to be bound strongly to the surface of a given sample. 
Type III: The platelets transformed to the extent of expanding thin cells 
to more than half of the length of pseudopodia, with the cells 
substantially completely spread out in a substantially circular pattern 
and suspected to be bound thoroughly to the surface of a sample. 
The results are shown in Table 7. 
TABLE 7 
______________________________________ 
Number of 
Form of platelet platelet attached 
Sample type I type II Type III 
number/0.07 mm2 
______________________________________ 
Example 1 
66.7 25.6 7.7 78 
Control 2 
62.3 31.2 6.5 93 
Control 3 
51.9 37.2 10.9 478 
______________________________________ 
It is clearly noted from Table 7 that the medical materials of this 
invention exhibit ideal resistance to thrombosis as compared with the 
untreated samples and the samples having a fatty acid fixed thereon.