CA1213097A - Elastomeric bladders for medical infusers - Google Patents
Elastomeric bladders for medical infusersInfo
- Publication number
- CA1213097A CA1213097A CA000396781A CA396781A CA1213097A CA 1213097 A CA1213097 A CA 1213097A CA 000396781 A CA000396781 A CA 000396781A CA 396781 A CA396781 A CA 396781A CA 1213097 A CA1213097 A CA 1213097A
- Authority
- CA
- Canada
- Prior art keywords
- antioxidant
- phr
- further characterized
- silicon dioxide
- bladder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
- A61M5/145—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons
- A61M5/148—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons flexible, e.g. independent bags
- A61M5/152—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons flexible, e.g. independent bags pressurised by contraction of elastic reservoirs
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- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Hematology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Anesthesiology (AREA)
- Vascular Medicine (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Medical Preparation Storing Or Oral Administration Devices (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Materials For Medical Uses (AREA)
- Infusion, Injection, And Reservoir Apparatuses (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
ELASTOMERIC BLADDERS FOR MEDICAL INFUSERS
Abstract Elastomeric bladders having improved resistance to spon-taneous rupture when inflated are made by vulcanizing a homo-geneous mixture of synthetic polyisoprene having 90% to 98%
cis-1,4 linkages, 3 to 10 phr fumed silicon dioxide, and vulc-anizing agent while simultaneously forming the mixture into hollow cylinderical bodies. After being formed the bodies are solvent extracted to remove unreacted vulcanizing agent and the degradation products of the vulcanizing agent. Following the solvent extraction about 0.2 to 2 phr of a nontoxic, non-leachable antioxidant are imbibed into the bodies by contacting the bodies with a liquid solution of the antioxidant.
Abstract Elastomeric bladders having improved resistance to spon-taneous rupture when inflated are made by vulcanizing a homo-geneous mixture of synthetic polyisoprene having 90% to 98%
cis-1,4 linkages, 3 to 10 phr fumed silicon dioxide, and vulc-anizing agent while simultaneously forming the mixture into hollow cylinderical bodies. After being formed the bodies are solvent extracted to remove unreacted vulcanizing agent and the degradation products of the vulcanizing agent. Following the solvent extraction about 0.2 to 2 phr of a nontoxic, non-leachable antioxidant are imbibed into the bodies by contacting the bodies with a liquid solution of the antioxidant.
Description
~ 3~ ARC-756 - ELASTOMERIC BLADDERS FOR MEDICAL INFUSERS
Description s Technical Field =, The invention relates to synthetic polyi~oprene bladder~
~or medioal infusers which have improved reslstance to ~pon-taneous rupture.
Background Art Medical devices that infuse liquids into patients are called infusers. One type of infuser uses an elastomeric bladder as its power so~rce. Such infusers and bladders are described in U.S. Patents NQS. 3,993,069 and 4,201,207. These infusers consist of a housing, an elastomeric bladder contained within the housing that is inflated with the liquid to be infused, and a conduit that leads from the bladder to the infusion site.
The rate at which the liquid is infused from the infuser depends upon the pressure exerted on the liquid by the bladder, the ~isc03ity of the liquid, and the ~low restriction characteristics of the conduit. The above cited patents describe bladders that are capable of maintaining the pressure on the liquid 3ubstantially constant over discharge o~ a large proportion of the liquid. The bladder~ de3cribed in these patents are made from vulcanized synthetic polyisoprene that has a low frequency hy~teresis less thar about 1~% and a stress relaxation less than about 10~. Such hysteresi~ and stress relaxation charac-teristics were considered as key factors in realizing substan-tially constant pressure performance.
In making large numbers of such bladders from synthetic polyisoprene it was found that a small but significant number of them ruptured when inflated- particularly after prolonged storage in an inflated state. Even though only a small portion of the bladdes 30 ruptured it was desirable to decrease the incidence o~ rupture in order to provide a greater margin of safety against rupture in the marketplace~ The above patent~
say nothing about reducing the incidence of bladder rupture.
3~
The present invention seeks to provide synthetic polyisoprene bladders that have a reduced incidence of rupture and acceptable pressure conskancy per-formance.
One aspect of the invention is an elastomeric bladder for use in a medical infuser that has improved resistance to rupture when :inflated, the b:lad-der being a tubular body (a) made from a vulcanized homogeneous mixture of synthetic polyisoprene having about 90% to about 98% cis-1,4 linkages and particulate silicon dioxide or particulate carbon black which have a nominal average diameter in the range of about 1 x 10 5 to about 5 x 10 3 mm and (b) into which a nontoxic substantially nonleachable antioxidant has been diffused, the amounts of silicon dioxide or carbon black and antioxidant being sufficient to make the half-life of a population of the bladders at least about ten times longer than the half-life of a comparable ~opulation of bladders made from said vulcanized synthetic polyisoprene that do not include the silicon di-oxide or carbon black and do not include the antioxidant.
Another aspect of the invention is a process for making an elastomeric bladder ~or use in a medical infuser and having an improved resistance to rup-ture when inflated comprising:
(a) mixing homogeneously a synthetic polyisoprene having about 90% to about 95 % cis~-1,4 linkages, about 3 to about 10phr particulate silicon dioxide or particulate carbon black which have a nominal average diameter in the range of about 1 x 10 5 to about 5 x 10 3 mm, and an amount of vulcanizing agent suffi-cient to vulcanize the mixture, (b) subjecting the mixture to vulcanizing conditions while simultaneously (c) forming the mixture into a tubular body;
(d) solvent extracting the degradation products of the vulcanizing agent from the body; and ~Z~3~7 (e) diffusing about 0.2 ta about 2 phr of a nontoxic substantially non-leachable antioxidant into the body by contacting the body with a liquid solu-tion of the antioxidant.
As used herein the designation "phr" means parts per hundred parts of synthetic polyisoprene.
The synthetic polyisoprene that is used to make the bladders has about 90% to about 98% of its monomeric units jained in cis~ orientation. lt is preferably of the type made using Ziegler catalysts which is characterized by having about g6% to about 98% cis~ linkages. This polyisoprene is mixed homo-geneously with particulate silicon dioxide or particulate carbon black or mix-tures thereof which have the above indicated particle size. Fumed silicon di-oxide is preferred. Such silicon dioxide is produced by the hydrolysis of sili-con tetrachloride vapor in a flame of hydrogen and oxygen at temperatures above the fusion temperature of silica (ca 1710 C). In this combustion process molten spheres of silica are formed that on cooling fuse with one another to form branched, three-dimensional, chain-like aggregates. The final product typically has a surface area in the range of about 150 to about 450 m2/gram as measured by the BET method. Such fumed silicon dioxides are sold by Cabot Corporation, Boston, Mass. under the trademark Cab-0-Sil ~ . The carbon black will typically have a surface area in the range of about 50 to about 250 m2/gram as measured by the BET method. The amount of silicon dioxide or carbon black that is mixed with the polyisoprene should be sufficient to substantially inhibit spontaneous rup-ture of the bladder due to the stresses that occur in the bladder walls when the bladder is inflated with medical fluid. About 3 to about 10 phr, preferably 3 to 7 phr, of the silicon dioxide or carbon black will normally be mixed with the synthetic polyisoprene. Lesser amounts will not give a significant increase in rupture resistance. More ~han 10 phr may be added, but such amounts do not pro-duce correspondingly greater enhancement of rupture resistance and may affect .
Description s Technical Field =, The invention relates to synthetic polyi~oprene bladder~
~or medioal infusers which have improved reslstance to ~pon-taneous rupture.
Background Art Medical devices that infuse liquids into patients are called infusers. One type of infuser uses an elastomeric bladder as its power so~rce. Such infusers and bladders are described in U.S. Patents NQS. 3,993,069 and 4,201,207. These infusers consist of a housing, an elastomeric bladder contained within the housing that is inflated with the liquid to be infused, and a conduit that leads from the bladder to the infusion site.
The rate at which the liquid is infused from the infuser depends upon the pressure exerted on the liquid by the bladder, the ~isc03ity of the liquid, and the ~low restriction characteristics of the conduit. The above cited patents describe bladders that are capable of maintaining the pressure on the liquid 3ubstantially constant over discharge o~ a large proportion of the liquid. The bladder~ de3cribed in these patents are made from vulcanized synthetic polyisoprene that has a low frequency hy~teresis less thar about 1~% and a stress relaxation less than about 10~. Such hysteresi~ and stress relaxation charac-teristics were considered as key factors in realizing substan-tially constant pressure performance.
In making large numbers of such bladders from synthetic polyisoprene it was found that a small but significant number of them ruptured when inflated- particularly after prolonged storage in an inflated state. Even though only a small portion of the bladdes 30 ruptured it was desirable to decrease the incidence o~ rupture in order to provide a greater margin of safety against rupture in the marketplace~ The above patent~
say nothing about reducing the incidence of bladder rupture.
3~
The present invention seeks to provide synthetic polyisoprene bladders that have a reduced incidence of rupture and acceptable pressure conskancy per-formance.
One aspect of the invention is an elastomeric bladder for use in a medical infuser that has improved resistance to rupture when :inflated, the b:lad-der being a tubular body (a) made from a vulcanized homogeneous mixture of synthetic polyisoprene having about 90% to about 98% cis-1,4 linkages and particulate silicon dioxide or particulate carbon black which have a nominal average diameter in the range of about 1 x 10 5 to about 5 x 10 3 mm and (b) into which a nontoxic substantially nonleachable antioxidant has been diffused, the amounts of silicon dioxide or carbon black and antioxidant being sufficient to make the half-life of a population of the bladders at least about ten times longer than the half-life of a comparable ~opulation of bladders made from said vulcanized synthetic polyisoprene that do not include the silicon di-oxide or carbon black and do not include the antioxidant.
Another aspect of the invention is a process for making an elastomeric bladder ~or use in a medical infuser and having an improved resistance to rup-ture when inflated comprising:
(a) mixing homogeneously a synthetic polyisoprene having about 90% to about 95 % cis~-1,4 linkages, about 3 to about 10phr particulate silicon dioxide or particulate carbon black which have a nominal average diameter in the range of about 1 x 10 5 to about 5 x 10 3 mm, and an amount of vulcanizing agent suffi-cient to vulcanize the mixture, (b) subjecting the mixture to vulcanizing conditions while simultaneously (c) forming the mixture into a tubular body;
(d) solvent extracting the degradation products of the vulcanizing agent from the body; and ~Z~3~7 (e) diffusing about 0.2 ta about 2 phr of a nontoxic substantially non-leachable antioxidant into the body by contacting the body with a liquid solu-tion of the antioxidant.
As used herein the designation "phr" means parts per hundred parts of synthetic polyisoprene.
The synthetic polyisoprene that is used to make the bladders has about 90% to about 98% of its monomeric units jained in cis~ orientation. lt is preferably of the type made using Ziegler catalysts which is characterized by having about g6% to about 98% cis~ linkages. This polyisoprene is mixed homo-geneously with particulate silicon dioxide or particulate carbon black or mix-tures thereof which have the above indicated particle size. Fumed silicon di-oxide is preferred. Such silicon dioxide is produced by the hydrolysis of sili-con tetrachloride vapor in a flame of hydrogen and oxygen at temperatures above the fusion temperature of silica (ca 1710 C). In this combustion process molten spheres of silica are formed that on cooling fuse with one another to form branched, three-dimensional, chain-like aggregates. The final product typically has a surface area in the range of about 150 to about 450 m2/gram as measured by the BET method. Such fumed silicon dioxides are sold by Cabot Corporation, Boston, Mass. under the trademark Cab-0-Sil ~ . The carbon black will typically have a surface area in the range of about 50 to about 250 m2/gram as measured by the BET method. The amount of silicon dioxide or carbon black that is mixed with the polyisoprene should be sufficient to substantially inhibit spontaneous rup-ture of the bladder due to the stresses that occur in the bladder walls when the bladder is inflated with medical fluid. About 3 to about 10 phr, preferably 3 to 7 phr, of the silicon dioxide or carbon black will normally be mixed with the synthetic polyisoprene. Lesser amounts will not give a significant increase in rupture resistance. More ~han 10 phr may be added, but such amounts do not pro-duce correspondingly greater enhancement of rupture resistance and may affect .
2~3~
the pressure constancy performance of the bladder adversely.
The polyisoprene-silicon dioxide/carbon black mixture is vulcanized to form carbon-to-carbon or monothio crosslinks at the 1 and ~ positions of the isoprene unit. To achieve such vulcanization a vulcanizing agent is added to the mixture and the mixture is subjected to vulcanizat:ion conditions. Vulcan-izing agents and procedures that may be used are disclosed in United States Patent No. 4,201,207 at column 2, line 54 to column 3, line 13 and in United States Patent No. 3,993,069 at column 8, line 50 to column 10, line 25.
Dicumyl peroxide added in amounts in the range of about 1 to 2 phr is a pre-ferred vulcanizing agent. The vulcanization will typically be effected during the forming process that is used to make the tubular bod:ies from the mixture.
One such process involves calendering the polyisoprene-silicon dioxide/carbon black-vulcanizing agent mixture into a sheet and placing a disc-shaped segment of the sheet into a transfer mold that forms the sheet into hollow cylindrical tubes of the desired geometry. Conventional injection molding techni~ues may also be used to form the body. The molding temperature, pressure, and time are such as to achieve the desired vulcanization (crosslinking) of the polyisoprene.
The geome~ry of the tubular bodies is the same as that disclosed in United States Patent No. 3,993,069 at column 4, lines 26 to 41.
After the mixture is formed into tubular bodies, the bodies are ex-tracted with a solvent that removes substantially all unreacted vulcanizing agent and the degradation products of the vulcanizing agent from the body. The solvent should have no lasting deleterious effects on the body and should not leave a toxic residue in or on the body. The particular solvent used and the extraction time and temperatwre will depend upon the vulcanizing agent that was used. The purpose of the extraction is to prevent contamination of the medical fluid that is ultimately charged to the bladder with the vulcanizing agent or its degradation products.
_ ~ _ v v ARC-756 After the extraction, the antioxidant is imbibed into the bodies by placing them into contact with a solution of the antioxidant. The antioxidant enters the bodies9 whlch ar~
usually swollen several fold with solvent~ by diffusion. The amount of antioxidant imbibed into a body will, accordingly~
depend upon the diffusion coefficient of the body with re~pect to the antioxidant, the concentration of the antioxidant ln the solution, the solubility of the antioxidant in the body, the thickness of the body5 the equilibrium swelling volume that is characteristic of ~he elastomeric-solvent combination, and the conditions (time and temperature) under which the contact is made. Preferably the same pure solvent is used for the extraction and antioxidant imbibition. The amount of antioxidant imbibed into the body should be sufficient to 1S inhibit oxidative degradation (and thus rupture) of the bladder, usually over a period of at least about one year. The quantity required to achieye such inhibition will depend on the particular antioxidant that is used.- In the case of the hindered phenol antioxidants described below, about 0.2 to about 2 phr, pre~erably about 1 phr, will usually be imbibed. Antioxidants 2~ that are nontoxic, such as those approved and under the provi sions of Title 21 of the Code of Federal Regulations for use in plastics that are used in association with drugs or food, and whieh are substantially nonleachable by the medical fluid with which the bladder is to be inflated may be used. The term "substantially nonleachable" means that the antioxidant is less than Q.1% by weight soluble in the medical fluid.
Nontoxie hindered polyphenol antioxidants) such as tetrakis emethylen~ 3-(3',5'~di-t-butyl-4'-hydroxyphenyl) propionate~
methane and 1,3,5-trimethyl-2,456-tris(395-di-t-butyl-4-4-hydroxybenzyl~ benzene, are pre~erred antioxidants for use inthe invention. After the desired amount of antioxidant has di~fused into th0 body, the body is taken from the solution and the solvent is removed from the body9 such as by drying at tempera~ures up to 50 C. At this stage, the bladder is ready for incorporation lnto the infuser.
~ 3~7 The incluslon of the silicon dioxide or carbon black and the antioxidant in the bladder together substantially reduce the likelihood that the bladder will rupture spontaneously when it is in~lated. T~is reduction (or increase in rupture re~istance) may be quantified relative to ~ynthetic polyisoprene bladders that do not contain silicon dioxide or carbon black and antioxidant by comparing the half-lives of populations of the respective bladders under the same inflation conditions.
The half-life is the time period from inflation to rupture of 50~ of the bladders in the population. A population of at least ten bladders is desired to ensure that the results are statistically significant. Such comparisons carried out at 40 C indicate that the half life of the invention bladders i3 at lea~t 10 times, and typically more than 100 times, longer than the half-life of bladders that do not contain silicon dioxide or carbon black and antioxidant.
The ~ollowing example illustrates one embodiment of the invention. This example is not intended to limit the invention and is of~ered only by way of exemplificationO
2~ Preparation of Mixture One hundred parts of synthetic polyisoprene (Natsyn 2200 , 96% to 98% cis-1,4 linkages) were added to a Farrell Laboratory Mill (6 in. x 13 in. roll~) at 130 + 10 F and the gap between rolls was adjusted to 0.08~0.09 in. After about 3 minuteq of milling, 5.0 phr fumed silicon dioxide (Cab-O-Sil~ M5, 200 +
25 m2/gram surface area, 1.4 x 10-5 mm nominal average diameter) were added to the mill over a 5 min. period. One and one-half phr o~ dicumyl peroxide (Di Cup R~ were then added to the polyisoprene-silicon dioxide mix in four equal portions.
Milling was continued until at least 18 min. had elapsed from the time the polyisoprene was added to the mill.
Vulcanization and Mold ng ~ .
The above mixture was charged to a four-cavity transfer mold maintained at 325-330 F and having 25,000 kg of clamping force. The mold cavities and mandrels were designed to make *
Trademark ~L2~
hollow cylindrical bladders 75.6 mm long with a 6.63 mm outer diameter and 5.16 mm inner diameter having diameter and having an integral circular flange at each end 1.587 mm wide and 12.7 mm in diameter. The curing time was 20 min~
Extraction Bladders ~ormed and vulcanized as above were placed vertically in the extraction pot of a Soxhlet exkraction apparatus fitked to a 1000 ml flask. Enough ethyl acetate was added to fill the Soxhlet apparatus and have 250 ml of ethyl acetate in the ~lask. The flask was heated and extraction of the bladders with the ethyl acetate was carried out for four hours.
Imbibition of Antioxidant A 1.1% by weight solution of 1,3,5-trimethyl-2,4,6-tris(3,4-di-t-butyl-4-hydr~xybenzyl) benzene in ethyl acetate was placed in a ~lask. Freshly extracted bladders were placed into-the solution and kept there at a~bient temperature for four hours.
Previous tests had shown that the relationship between the wt.
~ % oY this antioxidant imbibed into the bladders was linear with 0.45% imbibed at a 1% concentration, and 0.68% imbibed at 1.5% concentration (~our hours imbibition time). Accordingly about 0.5 phr antioxidant was imbibed into the b]adders.
~5 Half~ e Tests .
Half li~e test~ were carried out on bladders prepared as above except that 1.2 phr o~ tetrakis Lmethylene 3-(3',5'-di~
t-butyl-4'-hydroxyphenyl) propionate~ methane was imbibed into the bladders ~rom an acetone/toluene solution instead of the above described antioxidant. A population of 24 o~ these blad-ders inflated with 60 ml water and kept in air at 40 C had a hal~ life of approximately 14 months. Similar tests on popula-tions of synthetic polyisoprene bladd~r~ made in substantially the same manner but without silicon dioxide or antioxidant indieate such bladders have a half-life of about 1 to 2 days.
Modification of the above-described bladders that are obvious to those o~ ordinary skill in the arts related to the invention are intended to be within ~he scope of the following claims.
the pressure constancy performance of the bladder adversely.
The polyisoprene-silicon dioxide/carbon black mixture is vulcanized to form carbon-to-carbon or monothio crosslinks at the 1 and ~ positions of the isoprene unit. To achieve such vulcanization a vulcanizing agent is added to the mixture and the mixture is subjected to vulcanizat:ion conditions. Vulcan-izing agents and procedures that may be used are disclosed in United States Patent No. 4,201,207 at column 2, line 54 to column 3, line 13 and in United States Patent No. 3,993,069 at column 8, line 50 to column 10, line 25.
Dicumyl peroxide added in amounts in the range of about 1 to 2 phr is a pre-ferred vulcanizing agent. The vulcanization will typically be effected during the forming process that is used to make the tubular bod:ies from the mixture.
One such process involves calendering the polyisoprene-silicon dioxide/carbon black-vulcanizing agent mixture into a sheet and placing a disc-shaped segment of the sheet into a transfer mold that forms the sheet into hollow cylindrical tubes of the desired geometry. Conventional injection molding techni~ues may also be used to form the body. The molding temperature, pressure, and time are such as to achieve the desired vulcanization (crosslinking) of the polyisoprene.
The geome~ry of the tubular bodies is the same as that disclosed in United States Patent No. 3,993,069 at column 4, lines 26 to 41.
After the mixture is formed into tubular bodies, the bodies are ex-tracted with a solvent that removes substantially all unreacted vulcanizing agent and the degradation products of the vulcanizing agent from the body. The solvent should have no lasting deleterious effects on the body and should not leave a toxic residue in or on the body. The particular solvent used and the extraction time and temperatwre will depend upon the vulcanizing agent that was used. The purpose of the extraction is to prevent contamination of the medical fluid that is ultimately charged to the bladder with the vulcanizing agent or its degradation products.
_ ~ _ v v ARC-756 After the extraction, the antioxidant is imbibed into the bodies by placing them into contact with a solution of the antioxidant. The antioxidant enters the bodies9 whlch ar~
usually swollen several fold with solvent~ by diffusion. The amount of antioxidant imbibed into a body will, accordingly~
depend upon the diffusion coefficient of the body with re~pect to the antioxidant, the concentration of the antioxidant ln the solution, the solubility of the antioxidant in the body, the thickness of the body5 the equilibrium swelling volume that is characteristic of ~he elastomeric-solvent combination, and the conditions (time and temperature) under which the contact is made. Preferably the same pure solvent is used for the extraction and antioxidant imbibition. The amount of antioxidant imbibed into the body should be sufficient to 1S inhibit oxidative degradation (and thus rupture) of the bladder, usually over a period of at least about one year. The quantity required to achieye such inhibition will depend on the particular antioxidant that is used.- In the case of the hindered phenol antioxidants described below, about 0.2 to about 2 phr, pre~erably about 1 phr, will usually be imbibed. Antioxidants 2~ that are nontoxic, such as those approved and under the provi sions of Title 21 of the Code of Federal Regulations for use in plastics that are used in association with drugs or food, and whieh are substantially nonleachable by the medical fluid with which the bladder is to be inflated may be used. The term "substantially nonleachable" means that the antioxidant is less than Q.1% by weight soluble in the medical fluid.
Nontoxie hindered polyphenol antioxidants) such as tetrakis emethylen~ 3-(3',5'~di-t-butyl-4'-hydroxyphenyl) propionate~
methane and 1,3,5-trimethyl-2,456-tris(395-di-t-butyl-4-4-hydroxybenzyl~ benzene, are pre~erred antioxidants for use inthe invention. After the desired amount of antioxidant has di~fused into th0 body, the body is taken from the solution and the solvent is removed from the body9 such as by drying at tempera~ures up to 50 C. At this stage, the bladder is ready for incorporation lnto the infuser.
~ 3~7 The incluslon of the silicon dioxide or carbon black and the antioxidant in the bladder together substantially reduce the likelihood that the bladder will rupture spontaneously when it is in~lated. T~is reduction (or increase in rupture re~istance) may be quantified relative to ~ynthetic polyisoprene bladders that do not contain silicon dioxide or carbon black and antioxidant by comparing the half-lives of populations of the respective bladders under the same inflation conditions.
The half-life is the time period from inflation to rupture of 50~ of the bladders in the population. A population of at least ten bladders is desired to ensure that the results are statistically significant. Such comparisons carried out at 40 C indicate that the half life of the invention bladders i3 at lea~t 10 times, and typically more than 100 times, longer than the half-life of bladders that do not contain silicon dioxide or carbon black and antioxidant.
The ~ollowing example illustrates one embodiment of the invention. This example is not intended to limit the invention and is of~ered only by way of exemplificationO
2~ Preparation of Mixture One hundred parts of synthetic polyisoprene (Natsyn 2200 , 96% to 98% cis-1,4 linkages) were added to a Farrell Laboratory Mill (6 in. x 13 in. roll~) at 130 + 10 F and the gap between rolls was adjusted to 0.08~0.09 in. After about 3 minuteq of milling, 5.0 phr fumed silicon dioxide (Cab-O-Sil~ M5, 200 +
25 m2/gram surface area, 1.4 x 10-5 mm nominal average diameter) were added to the mill over a 5 min. period. One and one-half phr o~ dicumyl peroxide (Di Cup R~ were then added to the polyisoprene-silicon dioxide mix in four equal portions.
Milling was continued until at least 18 min. had elapsed from the time the polyisoprene was added to the mill.
Vulcanization and Mold ng ~ .
The above mixture was charged to a four-cavity transfer mold maintained at 325-330 F and having 25,000 kg of clamping force. The mold cavities and mandrels were designed to make *
Trademark ~L2~
hollow cylindrical bladders 75.6 mm long with a 6.63 mm outer diameter and 5.16 mm inner diameter having diameter and having an integral circular flange at each end 1.587 mm wide and 12.7 mm in diameter. The curing time was 20 min~
Extraction Bladders ~ormed and vulcanized as above were placed vertically in the extraction pot of a Soxhlet exkraction apparatus fitked to a 1000 ml flask. Enough ethyl acetate was added to fill the Soxhlet apparatus and have 250 ml of ethyl acetate in the ~lask. The flask was heated and extraction of the bladders with the ethyl acetate was carried out for four hours.
Imbibition of Antioxidant A 1.1% by weight solution of 1,3,5-trimethyl-2,4,6-tris(3,4-di-t-butyl-4-hydr~xybenzyl) benzene in ethyl acetate was placed in a ~lask. Freshly extracted bladders were placed into-the solution and kept there at a~bient temperature for four hours.
Previous tests had shown that the relationship between the wt.
~ % oY this antioxidant imbibed into the bladders was linear with 0.45% imbibed at a 1% concentration, and 0.68% imbibed at 1.5% concentration (~our hours imbibition time). Accordingly about 0.5 phr antioxidant was imbibed into the b]adders.
~5 Half~ e Tests .
Half li~e test~ were carried out on bladders prepared as above except that 1.2 phr o~ tetrakis Lmethylene 3-(3',5'-di~
t-butyl-4'-hydroxyphenyl) propionate~ methane was imbibed into the bladders ~rom an acetone/toluene solution instead of the above described antioxidant. A population of 24 o~ these blad-ders inflated with 60 ml water and kept in air at 40 C had a hal~ life of approximately 14 months. Similar tests on popula-tions of synthetic polyisoprene bladd~r~ made in substantially the same manner but without silicon dioxide or antioxidant indieate such bladders have a half-life of about 1 to 2 days.
Modification of the above-described bladders that are obvious to those o~ ordinary skill in the arts related to the invention are intended to be within ~he scope of the following claims.
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An elastomeric bladder for use in a medical infuser comprising a tubu-lar body formed of a vulcanized homogeneous mixture of synthetic polyisoprene having about 90% to about 98% cis-1,4 linkages said bladder having improved re-sistance to rupture when inflated and being characterized by containing particu-late silicon dioxide or particulate carbon black having a nominal average parti-cle diameter in the range of about 1 x 10-5 to about 5 x 10-3 mm; and a nontoxic, substantially nonleachable antioxidant diffused throughout the mixture, the amounts of silicon dioxide or carbon black and antioxidant being sufficient to make the half-life of a population of the bladders at 40°C at least about ten times longer than the half-life of a comparable population of bladders made from said vulcanized synthetic polyisoprene but without the silicon dioxide or carbon black and without the antioxidant.
2. The elastomeric bladder of claim 1 further characterized in that the particulate silicon dioxide is fumed silicon dioxide and is present in amounts of from 3 to 10 phr.
3. The elastomeric bladder of claim 1 further characterized by the syn-thetic polyisoprene having about 96% to 98% cis-1,4 linkages.
4. The elastomeric bladder of claim 1 further characterized by the vul-canized synthetic polyisoprene having carbon-to-carbon crosslinks.
5. The elastomeric bladder of claim 1 further characterized by containing from about 0.2 to about 2 phr of the nontoxic, substantially nonleachable anti-oxidant.
6. The elastomeric bladder of claim 1 being further characterized by containing about 3 to about 7 phr of fumed silicon dioxide having a surface area in the range of about 150 to about 450 m2/gram.
7. The elastomeric bladder of Claim 6 further characterized by the sur-face area being 200 ? 20 m2/gram.
8. The elastomeric bladder of Claim 1 being further characterized by the antioxidant being a hindered polyphenol.
9. The elastomeric bladder of Claim 8 being further characterized by the hindered polyphenol being tetrakis[methylene 3-(3',5',di-t-butyl-4'-hydroxy-phenyl)propionate]methane or 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxy-benzyl) benzene.
10. The elastomeric bladder of claim 9 being further characterized by be-ing vulcanized with about 1.5 phr dicumyl peroxide; and containing about 1 phr of 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) benzene.
11. A process for making an elastomeric bladder for use in a medical in-fuser having improved resistance to rupture when inflated comprising mixing homo-geneously a synthetic polyisoprene having about 90% to about 98% cis-1,4 link-ages, a sufficient amount of particulate silicon dioxide or particulate carbon black which have a nominal average diameter in the range of about 1 x 10-5 to about 5 x 10-3 mm to substantially inhibit spontaneous rupture of the bladder due to stress in the bladder wall caused by inflation of the bladder and an amount of vulcanizing agent sufficient to vulcanize the mixture and vulcanizing said mixture said process being characterized by subjecting the mixture to vulcanizing conditions while simultaneously:
(a) forming the mixture into a tubular body;
(b) solvent extracting unreacted vulcanizing agent and the degradation pro-ducts of the vulcanizing agent from the body; and (c) diffusing a nontoxic, substantially nonleachable antioxidant into the body by contacting the body with a liquid solution of the antioxidant, the amount of antioxidant diffused into the body being sufficient to substantially inhibit oxidative degradation of the body.
(a) forming the mixture into a tubular body;
(b) solvent extracting unreacted vulcanizing agent and the degradation pro-ducts of the vulcanizing agent from the body; and (c) diffusing a nontoxic, substantially nonleachable antioxidant into the body by contacting the body with a liquid solution of the antioxidant, the amount of antioxidant diffused into the body being sufficient to substantially inhibit oxidative degradation of the body.
12. The process of Claim 11 being further characterized by said synthetic polyisoprene being mixed with fumed silicon dioxide.
13. The process of Claim 12 being further characterized by the amount of fumed silicon dioxide being about 3 to about 10 phr, the antioxidant being a hindered polyphenol, and the amount of antioxidant being about 0.5 to about 2 phr.
14. The process of Claim 13 being further characterized by the fumed sili-con dioxide having a surface area of 200 + 20 m2/gram, the amount of fumed sili-con dioxide being 5 phr, the vulcanizing agent being dicumyl peroxide, the amount of vulcanizing agent being 1.5 phr, the antioxidant being tetrakis [methylene 3-(3',5',di-t-butyl-4'-hydroxyphenyl) propionate] methane or 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, and the amount of antioxidant being about 0.2 to about 2 phr.
15. The process of Claim 14 being further characterized by antioxidant being 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) benzene, the amount of antioxidant being 1 phr, the solvent being ethyl acetate, and the antioxidant being dissolved in ethyl acetate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US23732581A | 1981-02-23 | 1981-02-23 | |
| US237,325 | 1981-02-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1213097A true CA1213097A (en) | 1986-10-21 |
Family
ID=22893262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000396781A Expired CA1213097A (en) | 1981-02-23 | 1982-02-22 | Elastomeric bladders for medical infusers |
Country Status (21)
| Country | Link |
|---|---|
| JP (1) | JPS57156772A (en) |
| AR (1) | AR228472A1 (en) |
| AT (1) | AT386953B (en) |
| AU (1) | AU548485B2 (en) |
| BE (1) | BE892189A (en) |
| BR (1) | BR8200915A (en) |
| CA (1) | CA1213097A (en) |
| CH (1) | CH658194A5 (en) |
| DE (1) | DE3206377A1 (en) |
| DK (1) | DK159051C (en) |
| ES (1) | ES8304847A1 (en) |
| FR (1) | FR2502013B1 (en) |
| GB (1) | GB2093473B (en) |
| IE (1) | IE52850B1 (en) |
| IL (1) | IL65081A (en) |
| IT (1) | IT1191167B (en) |
| MX (1) | MX163246B (en) |
| NL (1) | NL189111C (en) |
| NO (1) | NO154181C (en) |
| SE (1) | SE452711B (en) |
| ZA (1) | ZA82268B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4419096A (en) * | 1982-02-22 | 1983-12-06 | Alza Corporation | Elastomeric bladder assembly |
| EP0117015A1 (en) * | 1983-01-10 | 1984-08-29 | Tompkins Rubber Company | A rubber based medical component for a medical infusion set |
| WO1988000841A1 (en) * | 1986-08-08 | 1988-02-11 | Edward John Keogh | Expansible chamber drug infuser system |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1195926A (en) * | 1968-05-08 | 1970-06-24 | Oliver Wallis Burke Jr | Silica Pigment Reinforced Hydrocarbon Rubber Compounded Stocks and Vulcanizates thereof and Processes for Producing the Same. |
| FR2078078A5 (en) * | 1970-02-26 | 1971-11-05 | Pirelli | |
| US4201207A (en) * | 1973-03-26 | 1980-05-06 | Alza Corporation | Bladder for liquid dispenser |
| US3993069A (en) * | 1973-03-26 | 1976-11-23 | Alza Corporation | Liquid delivery device bladder |
| DE2822148C2 (en) * | 1978-05-20 | 1983-02-24 | Chemische Werke Hüls AG, 4370 Marl | Process for the production of a powdery, filler-containing rubber |
-
1982
- 1982-01-08 AU AU79406/82A patent/AU548485B2/en not_active Ceased
- 1982-01-08 GB GB8200523A patent/GB2093473B/en not_active Expired
- 1982-01-15 ZA ZA82268A patent/ZA82268B/en unknown
- 1982-01-21 DK DK025582A patent/DK159051C/en not_active IP Right Cessation
- 1982-01-21 NL NLAANVRAGE8200218,A patent/NL189111C/en not_active IP Right Cessation
- 1982-01-29 AR AR288296A patent/AR228472A1/en active
- 1982-02-10 AT AT0049982A patent/AT386953B/en not_active IP Right Cessation
- 1982-02-10 IT IT67153/82A patent/IT1191167B/en active
- 1982-02-18 CH CH1027/82A patent/CH658194A5/en not_active IP Right Cessation
- 1982-02-18 SE SE8201009A patent/SE452711B/en not_active IP Right Cessation
- 1982-02-18 ES ES509733A patent/ES8304847A1/en not_active Expired
- 1982-02-18 BE BE0/207346A patent/BE892189A/en not_active IP Right Cessation
- 1982-02-19 BR BR8200915A patent/BR8200915A/en not_active IP Right Cessation
- 1982-02-22 NO NO820536A patent/NO154181C/en unknown
- 1982-02-22 CA CA000396781A patent/CA1213097A/en not_active Expired
- 1982-02-22 DE DE19823206377 patent/DE3206377A1/en active Granted
- 1982-02-22 IE IE370/82A patent/IE52850B1/en not_active IP Right Cessation
- 1982-02-23 IL IL65081A patent/IL65081A/en not_active IP Right Cessation
- 1982-02-23 FR FR828202924A patent/FR2502013B1/en not_active Expired
- 1982-02-23 JP JP57028040A patent/JPS57156772A/en active Granted
- 1982-02-25 MX MX191525A patent/MX163246B/en unknown
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| MKEX | Expiry |