Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-06-19
2001-02-20
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C604S265000
Reexamination Certificate
active
06191192
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to antibacterial polymeric moldings and more particularly to antibacterial polymeric molded products suitable as urethral catheters, gloves or the like, and to a process for preparing the molded product.
PRIOR ART
The urethral catheter is a medical device designed to stay in an organism, and therefore, has been disinfected or sterilized by some means before use. However, the urethral catheter is mostly used for a long time, thus frequently failing to remain aseptic during use. The urethral catheter can not be kept aseptic because of penetration of bacteria from outside via the inside or outside of the catheter passageway which is responsible for the development of infectious diseases such as urethritis, cystitis, pyelonephritis or the like. Consequently there is now a demand for improvements in urethral catheters.
As a preventive measure against infectious diseases, chemotherapy has been performed by the administration of antibiotics or the like. However, the chemotherapy requires the administration of antibiotics in large doses, unavoidably entailing a problem of side effects depending on the type of antibiotics. While chemotherapy can temporarily sterilize the bacteria, the patient, once seized with such diseases, would be likely to become reinfected upon advent of resistant bacteria. Hence this problem would be attendant on chemotherapy not deliberately conducted.
The most effective measure against infectious diseases is to impart an antibacterial property to the urethral catheter in its entirety or the surface thereof.
Typical examples of antibacterial agents are heavy metals such as gold, silver, copper and zinc and their metal compounds. These antibbacterial agents have a broad antibacterial spectrum as metal ions against bacteria and fungi even in extremely small amounts. Attempts have been heretofore made to produce urethral catheters with their matrix containing these metal compounds to make the catheters antibacterial.
Quaternary ammonium salts are cationic antibacterial substances and available as other antibacterial compounds than the metal compounds. The quaternary ammonium salts show a high antibacterial activity and have been incorporated, like the metal compounds, into the matrix of urethral catheters to make the catheters antibacterial.
Further, a need has arisen for antibacterial gloves as well as for antibacterial urethral catheters, such as gloves for medical use in operations or inspection or for food-processing purposes in order to prevent the contagion of infectious diseases or to improve the hygienic conditions.
A composition comprising a natural rubber latex or a synthetic rubber latex containing silver protein (Japanese Examined Patent Publication No.88900/1993) and a composition comprising silicone rubber containing silver protein (Japanese Examined Patent Publication No.55892/1994) are reported as antibacterial compositions comprising a polymeric compound containing a silver-based antibacterial substance. The application of a silver-based antibacterial substance in urethral catheters is reported in Japanese Examined Patent Publication No.34817/1994 which discloses a coating composition comprising a natural rubber latex or a synthetic rubber latex containing silver protein used in a process for producing a urethral catheter by a coating method such as a dipping method.
Japanese Examined Patent Publication No.11813/1994 discloses an antibacterial composition comprising a natural rubber latex containing a cationic antibacterial substance. Japanese Examined Patent Publication No.74026/1992 discloses a urethral catheter produced from silicone rubber having a water-soluble cationic antibacterial substance dispersed therein as urethral catheters containing a cationic antibacterial substance. Further, Japanese Examined Patent Publication No.64143/1991 describes a urethral catheter produced from an organic high molecular elastomer having a sparingly water-soluble quaternary ammonium salt dispersed therein.
However, various drawbacks are entailed in molding processes using the above-mentioned compositions comprising an organic high molecular compound having dispersed therein an antibacterial substance such as silver protein or quaternary ammonium salt. For example, it is difficult in the process to maintain the antibacterial substance as stably dispersed in the organic high molecular compound for a long time. Further, the latex particles are likely to aggregate and the antibacterial substance (especially metal compounds) tends to precipitate, resulting in formation of ununiform coating layer and difficulty in obtaining a stable antibacterial property.
Other problems are posed by processes using an organic high molecular compound having an antibacterial substance dispersed therein. For example, after molding the desired product from the organic high molecular compound, the molded product is exposed to a high temperature in post treatment such as vulcanization so that the antibacterial substance is oxidized or thermally decomposed, tending to lower the stability owing to the decomposition product and to form, in some case, black particles due to the precipitation of silver or like antibacterial component.
The antibacterial substance can be introduced into a urethral catheter or the like otherwise than by dispersing the antibacterial substance in the base material. For example, Japanese Examined Patent Publication No.10341/1991 discloses a method wherein a solution containing a biguanide compound as a water-soluble antibacterial substance is absorbed into the urethral catheter, and then the antibacterial substance is converted into a sparingly water-soluble compound. Also available is a method wherein after molding a latex, the molded product is immersed before cure into a solution containing an antibacterial substance to absorb the antibacterial substance into the molded product, as disclosed in Japanese Unexamined Patent Publication (PCT) No.502111/1992.
However, the above-mentioned methods of introducing the antibacterial substance into a urethral catheter using a solution containing the antibacterial substance are not economical because the antibacterial substance is slowly absorbed into the base material and the operation takes several days. Further, the antibacterial substance dissolves out early during use so that the antibacterial activity may be retained only for a short period.
Also known is a producing method wherein a coating layer having maleic anhydride group is formed on the surface of the urethral catheter using a composition containing a polyfunctional compound and a copolymer containing maleic anhydride as a monomer component and then the antibacterial substance is bonded to the coating layer after hydrolysis of maleic anhydride group, as disclosed in Japanese Examined Patent Publication No.24544/1990. However, this method requires the step of forming a coating layer containing maleic anhydride group and the step of hydrolyzing the maleic anhydride group, that is, posing a problem of involving an increased number of steps.
DISCLOSURE OF THE INVENTION
A primary object of the present invention is to provide an antibacterial polymeric molded product having a high antibacterial property and an ability to sustain a high antibacterial activity for a long time.
Another object of the invention is to provide an antibacterial molded product which is suitable as an antibacterial urethral catheter or as antibacterial gloves.
A further object of the invention is to provide a process capable of easily producing an antibacterial organic polymeric molded product which can sustain a high antibacterial activity for a long time.
The present inventors conducted extensive research to achieve the foregoing objects and found that the contemplated molded product can be produced by the following processes. Proposed is a process wherein the molded product is produced from a polymeric compound containing an anionic compound capable of combining, by ionic bond, with a cationic component of a water-soluble antibacterial
Arimori Susumu
Monden Noriko
Seko Masahiro
Tanaka Masakazu
Yokota Hideyuki
Foley & Lardner
Hoke Veronica P.
Toyo Boseki Kabushiki Kaisha
LandOfFree
Antibacterial polymeric moldings does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antibacterial polymeric moldings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antibacterial polymeric moldings will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2584853