WO2007085971A2

WO2007085971A2 - Water barrier for medical device

Info

Publication number: WO2007085971A2
Application number: PCT/IB2007/001196
Authority: WO
Inventors: Teoh Lian Huah; Sathish Komar Subramaniam
Original assignee: CR Bard Inc
Current assignee: CR Bard Inc
Priority date: 2006-01-24
Filing date: 2007-01-24
Publication date: 2007-08-02
Anticipated expiration: 2008-07-24
Also published as: WO2007085971A3

Abstract

The present disclosure relates to a coating providing water-barrier properties, as well as a device containing such a coating, such as a medical device, for example a catheter. Also disclosed herein is a process for improving the water-barrier properties of a medical device.

Description

WATER BARRIER FOR MEDICAL DEVICE

BACKGROUND

[0001] The present disclosure relates to a coating for a medical device, such as a pre- filled Foley catheter.

[0002] A pre-filled Foley catheter can be regarded as one example of a medical device with a proximal end and a distal end, an elastomeric reservoir bulb on an inflation arm at the proximal end for storing fluid under pressure, a fluid acceptor at the distal end, and a lumen connecting the bulb and the acceptor for flow of fluid from the bulb to the acceptor when the device is used. The device also includes a control device at the proximal end of the lumen to prevent said fluid flow until said flow is desired.

[0003] The Foley catheter is a catheter device usually made out of elastomeric material, such as latex, and which is installed with its distal end in the bladder of the patient for urine drainage. When the distal end of the catheter has been advanced into the bladder, sterile water is caused to flow along a lumen from the proximal to the distal end of the catheter, there to fill a balloon at the distal end of the catheter. This balloon retains the distal end of the catheter in the bladder and allows a second lumen in the catheter shaft, open to the bladder at the distal end of the shaft, to drain urine from the bladder to the proximal end of the catheter.

[0004] In a pre-filled Foley catheter, such as shown in U.S. Pat. No. 3,602,226 and U.S. 6,979,313 (the disclosures of which are incorporated herein by reference in their entirety) the device includes a reservoir of sterile water in the proximal end of the device, and a clip over the shaft of the catheter at its proximal end, which clip prevents the sterile water from flowing from the distended reservoir bulb along the lumen to the distal end of the catheter. The person placing the catheter is required to hold the catheter in the desired disposition relative to the body of the patient, and then remove the clip and squeeze the reservoir bulb in order to inflate the balloon.

[0005] Achievement of satisfactory shelf-life for pre-filled Foley catheters has proved to be a challenge. Common elastomeric material, such as latex, is not entirely impermeable to the passage of water. Accordingly, the water in the distended bulb reservoir of elastomeric material can escape through the wall, given enough time. In order to achieve a satisfactory shelf-life (18 to 24 months) it has been proposed to cover the outside of the reservoir bulb with a coating of material more resistant to passage of water than latex. Nevertheless, residual problems remain, some of which are discussed in U.S. Pat. No. 3,602,226.

[0006] One such problem is that the coating tends to crack. This reduces the resistance to escape of water and can adversely affect appearance. Another problem is to achieve satisfactory continuity of the coating around the clip at the distal end of the bulb, and the customary filler valve at the proximal end of the bulb. Even then, there is potential for water to escape from the bulb by flowing lengthways along the elastomeric material of the wall of the bulb, until it has passed the distal and proximal ends of the waterproof coating material. [0007] The reservoir bulb on the inflation arm of the catheter is typically coated with Saran^® F310 copolymer of vinylidene chloride and acrylonitrile to prevent loss of water through the latex membrane. It could be desirable to provide a reservoir bulb with a improved coating that further inhibits the diffusion of water therethrough.

SUMMARY

[0008] According to various embodiments, there is provided a coating for a medical device, comprising a copolymer of vinylidene chloride and acrylonitrile, an acrylonitrile butadiene polymer, and at least one solvent.

[0009] According to various embodiments, there is provided a medical device having a coating on at least a portion of the surface thereof, said coating comprising a copolymer of vinylidene chloride and acrylonitrile, an acrylonitrile butadiene polymer, and at least one solvent.

[00010] According to various embodiments, there is provided a process for improving the ability of a device to resist the passage of water therethrough, said process comprising coating said device with a coating comprising a copolymer of vinylidene chloride and acrylonitrile, an acrylonitrile butadiene polymer, and at least one solvent.

DESCRIPTION

[00011] As is described in the foregoing, disclosed herein is a coating providing water- barrier properties, as well as a device containing such a coating, such as a medical device, for example a catheter. Also disclosed herein is a process for improving the water-barrier properties of a medical device.

[00012] According to various embodiments, the present disclosure improves the water- barrier properties of polymeric coatings, such as coatings comprising vinylidene chloride acrylonitrile copolymers, for example Saran^® F310 polymer available from Dow Chemical (Midland, MI). According to various embodiments, the coatings are modified with at least one polymer, such as a copolymer, for example a copolymer of acrylonitrile and butadiene. Such modified coatings can provide at least one of reduced cracking, reduced number of micropores, and good barrier integrity as compared to both uncoated latex and latex coated with only the Saran^® F310 polymer.

[00013] According to various embodiments, the at least one polymer is an elastomer and/or has low gas permeability. Such polymers are well-known to those of ordinary skill in the art. A suitable non-limiting example of such a polymer is a copolymer of acrylonitrile and butadiene, such as acrylonitrile butadiene rubber, for example that which is sold under the trade name Nipol DN 3350 (Zeon Chemicals, LP, Louisville, KY). Nipol DN 3350 is a suitable example at least because it is an elastomer with low gas permeability.

[00014] According to various embodiments, the coatings are additionally modified with at least one solvent, such as an organic solvent. Suitable non-limiting examples of organic solvents include tetrahydrofuran, ketones such as cyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone and isophorone; esters; ethers such as 2-ethoxyethyl acetate, propylene glycol methyl ether acetates; and aromatic solvents such as toluene, xylene, and aromatic solvent blends derived from petroleum. According to various embodiments, two organic solvents are used in the coatings according to the present disclosure. According to various embodiments, tetrahydrofuran is an example of a suitable solvent because it is compatible with acrylonitrile butadiene rubber and facilitates the binding of the coating to the latex inflation arm.

[00015] The acrylonitrile butadiene copolymer is added to the acrylonitrile vinylidene chloride copolymer as the secondary barrier preventing the water loss. The elasticity properties of the acrylonitrile butadiene copolymer act as a plasticizer in the polymer blend, providing a synergistic effect in the barrier polymer mixture, thereby enhancing the coating and retaining the water in the device, such as in the latex inflation arm. The NBR elastomer causes the acrylonitrile vinylidene chloride copolymer to plasticize, which prevents the coating surface from cracking, thus reducing water loss. [00016] According to various embodiments, the coating is formulated with various proportions of ingredients. For example, the copolymer of vinylidene chloride and acrylonitrile can be present in an amount ranging from about 1 to about 15%, for example about 10 to about 15%, such as from about 11 to about 14%, for example from about 12 to about 13% by weight, relative to the total weight of the mixture. The acrylonitrile and butadiene copolymer can be present in an amount ranging from about 0.1 to about 10% by weight, such as from about 1 to about 5% by weight, relative to the total weight of the composition. According to various embodiments, the at least one solvent is present in an amount ranging from about 85 to about 99%, such as from about 86 to about 89%, such as from about 88 to about 87% by weight, relative to the total weight of the composition. [00017] According to various embodiments, the coating comprises 12% polymer Saran^® F310 and 1% acrylonitrile butadiene copolymer dissolved in the blend of 62% THF and 25% acetone solvent.

[00018] For the purposes of this specification and appended claims, unless otherwise indicated, all numbers used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[00019] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a range of "1 to 10" includes any and all subranges between (and including) the minimum value of 1 and the maximum value of 10, that is, any and all subranges having a minimum value of equal to or greater than 1 and a maximum value of equal to or less than 10, e.g., 5.5 to 10. [00020] It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to "a solvent" includes two or more solvents.

[00021] Other various embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. Use of a solution of acrylonitrile butadiene polymer as a plasticizer in a coating composition that comprises a copolymer of vinylidene chloride and acrylonitrile and is to serve as a water barrier.

2. Use as claimed in claim 1, wherein the solvent is tetrahydrofuran.

3. Use as claims in claim 1 or 2 , wherein the coating composition coats a latex substrate.

4. Use as claimed in claim 3, wherein the substrate is a Foley catheter.

5. A coating for a medical device, comprising: a copolymer of vinylidene chloride and acrylonitrile; an acrylonitrile butadiene polymer; and at least one solvent.

6. The coating according to claim 5, wherein the at lest one solvent is an organic solvent.

7. The coating according to claim 6, wherein the organic solvent is chosen from tetrahydrofuran and acetone.

8. The coating according to claim 5, 6 or 7, comprising two solvents .

9. The coating according to any one of the preceding claims, wherein the copolymer of vinylidene chloride and acrylonitrile is present in an amount ranging from about 0.1 to about 20% by weight, relative to the total weight of the barrier.

10. The coating according to any one of the preceding claims, wherein the acrylonitrile butydiene lolymer is present in an amount ranging from about 5 to about 15% by weight, relative to the total weight of the barrier.

11. The coating according to any one of the preceding claims, wherein: the copolymer of vinylidene chloride and acrylonitrile is present in an amount ranging from about 10 to about 15%; the acrylonitrile butadiene polymer is present in an amount ranging from about 1 to about 3%; and the at least one solvent is present in an amount ranging from about 65 to about 85%.

12. A medical device having a coating on at least a portion of the surface thereof, said coating comprising: a copolymer of vinylidene chloride and acrylonitrile; an acrylonitrile butadiene polymer; and at least one solvent.

13. The medical device according to claim 12, wherein said medical device is a catheter.

14. The medical device according to claim 13, wherein said other is a Foley catheter.

15. The medical device according to claim 14, wherein said Foley catheter is a pre-filled Foley catheter.

16. The medical device according to any one of claims 13 to 15, wherein the catheter comprises an elastomeric reservoir bulb, and the coating is disposed on at least one surface of said bulb.

17. The medical device according to claim 12, wherein said surface portion having the coating comprises latex rubber.

18. The medical device according to any one of claims 12 to 17, wherein the water permeability of the coated portion is less than that of uncoated latex rubber.

19. Device according to claim 18, wherein the resistance to the passage of water through the coated portion is less than that of the same latex rubber but coated instead with an equivalent coating created from a 12% (relative to the total weight of solution) solution of a copolymer of vinylidene chloride and acrylonitrile and devoid of acrylonitrile butadiene polymer .

20. A process for improving the ability of a device to resist the passage of water therethrough, said process comprising coating said device with a coating comprising: a copolymer of vinylidene chloride and acrylonitrile; an acrylonitrile butadiene polymer; and at least one solvent.

21. The process according to claim 20, wherein said medical device is a catheter.

22. The process according to claim 21, wherein said catheter is a Foley catheter.

23. The process according to claim 22, wherein said Foley catheter is a pre-filled Foley catheter.