| Suturable adhesion-preventing membrane -> Monitor Keywords |
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Suturable adhesion-preventing membraneRelated Patent Categories: Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor, Implantable Prosthesis, Having Means To Promote Cellular AttachmentSuturable adhesion-preventing membrane description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060041320, Suturable adhesion-preventing membrane. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a division of application Ser. No. 09/489,473 filed Jan. 21, 2005, which claims priority of Japanese patent application Nos. 11-12625 filed Jan. 21, 1999, and 11-85477 filed Mar. 29, 2005, which are incorporated herein by reference. FIELD OF THE INVENTION [0002] This invention relates to a suturable adhesion-preventing membrane, and more particularly to a suturable adhesion-preventing membrane based on collagen and used for guided tissue regeneration. Even more particularly, the invention relates to a membrane that is utilized in a living body as an adhesion-preventing membrane for a prosthesis; to repair, augment or replace parts of tissues and organs that have been destroyed or weakened by disease or trauma or surgical operation such as abdominal wall defects or excised, transected, ablated or resected sites in tissues within a living body such as the pleura, pericardium, cerebral dura mater and chorion, and various organs. The membrane of the present invention is characterized by, in particular, being suturable, having good biocompatibility, and further, promoting tissue regeneration BACKGROUND OF THE INVENTION [0003] In various surgical operations, an ablation of affected parts, a repair of damaged sites and surfaces or the like is very often conducted. Especially, in the surgical operations for various organs such as the lungs, heart, liver, brain, digestive organs and gallbladder, unless the resected site or defective part of the organs or the like is replaced or repaired or augmented (i.e., compensated) with a membranous substance covering the tissue of such organs, the fundamental functions of the organ will be damaged in many cases. If the treatment is not completely performed, the patient will die due to a malfunction of the organ or, even if the patient passes the crisis, an often observed tendency is that the prognosis is quite bad. Also, with respect to an insufficient suture fixation of the membranous substance in a prosthetic or compensated part, even if the function of the treated organ itself manages to be maintained, body fluids, digestive juices or contents which are exuded or leak from the organ may cause infection, or cause an attack or an erosion of other organs to eventually jeopardize life. [0004] Further, there happens highly frequently an adhesion of the membranous substance at these prosthetic or compensated parts, and consequently, a malfunction of the organ may be induced in the course of time. In order to solve such problems, membranous substances or adhesion-preventing membranes made of various materials have been developed to cover the organ or the tissue of the organ. [0005] Conventionally, a surgical wound dressing material is known in which a non-woven fabric layer made of collagen fibers is treated with aldehydes to have water resistance and the fibers are bonded mutually with collagen (Japanese Unexamined Patent Publication No. 141190/1975). However, because the surface of the dressing material is treated with a cross-linking agent, the material has inferior biocompatibility or is inferior in guiding tissue regeneration. Further, it is uncertain whether the dressing material can function to have sufficient suture strength or prevent an adhesion of a wound although it covers the wound. [0006] In the above conventional technique, the adhesion-preventing membrane exhibits insufficient adhesion-preventing effects, suture strength, biocompatibility and decomposition and absorption capability in a living body, and particularly, the membrane can not simultaneously exhibit these characteristics. Therefore, the aim of the present invention is to resolve simultaneously the conventional problems of adhesion-preventing membranes that include insufficient suture strength, insufficient biocompatibility or decomposition and absorption capability in a living body, and insufficient adhesion-preventing effects as well. [0007] The present inventor has already proposed as an improved medical membrane utilizing only animal collagen, a medical collagen membrane of non-woven fabric layer which comprises cross-linked collagen in which at least one surface of a membrane is covered with a-collagen coating (Japanese Patent Application No. 264891/1998). Because the surface of the membrane is not cross-linked with a cross-linking agent, the membrane is superior in biocompatibility, guiding tissue regeneration and the like as compared to a surgical wound dressing material in which a non-woven fabric layer made of collagen fibers is treated with aldehydes to have water resistance and the fibers are bonded mutually with collagen (Japanese Unexamined Patent Publication No.141190/1975). Also, another characteristic of the membrane is to have a wide variety of applications for surgical procedures as in, particularly, compensation or prothesis of various organs, since the membrane can be fixed directly to the organs by means of a suture. Additionally, the membrane especially has strength enough to withstand suture fixation compared to a patch for visceral surgery which is comprised of two layers of (1) porous fibrous collagen layer and (2) collagen and/or a gelatin membrane (Japanese Patent No. 2775115). Therefore, it is possible for the membrane to be fixed more firmly to application sites with a general and inexpensive surgical suture thread as compared to fixation with only a biological adhesive, and a wide range of surgical applications are characteristically provided. [0008] However, the above improved membrane has a difficulty in obtaining a sufficient adhesion-preventing property because the raw material of the membrane is collagen derived from an animal, which promotes adhesion, proliferation and extension of cells. Therefore, it is an object of the present invention to provide a suturable and adhesion-preventing membrane for guided tissue regeneration which is superior in suture strength, biocompatibility and guiding tissue regeneration, and further has an adhesion-preventing property. SUMMARY OF THE INVENTION [0009] As a result of intensive research to solve such problems, the present inventor has found that when at least one non-woven fabric layer made of collagen fibers is used to form a membrane, or a non-woven fabric layer made of collagen fibers and a sponge layer made of collagen are used to form a membranous substance having a laminated structure, and a coating layer containing gelatin or hyaluronic acid is provided on the surface of the membrane or the membranous substance, a desired membrane is formed that has sufficient suture strength, good biocompatibility, a property for promoting tissue regeneration and a sufficient adhesion-preventing effect, thus completing the present invention. [0010] The present invention is directed to a suturable adhesion-preventing membrane for guided tissue regeneration comprising a membrane having at least one non-woven fabric layer made of collagen fibers, or a laminated membranous substance having at least one non-woven fabric layer made of collagen fibers and at least one sponge layer made of collagen, characterized in that at least one surface of the membrane or laminated membranous substance is provided with at least one coating layer containing gelatin or hyaluronic acid. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIGS. 1 to 4 are flow charts illustrating the processes described in Examples 1, 2, 6 and 7, respectively, for preparing suturable adhesion-preventing membranes of the present invention. DETAILED DESCRIPTION [0012] Now, the most simple and effective way to prevent adhesion is to avoid contact between tissues damaged by injury or deficit and other tissues that have possibility of physically contacting the damaged tissue by means of barrier. However, a barrier made of synthetic fibers and the like causes various disadvantages such as excessive calcification, xenobiotic reaction, an inflammatory response and the like because of insufficient biocompatibility. Accordingly, the barrier material itself should not mediate the adhesion of damaged or defective tissues to other tissues corresponding thereto. Hyaluronic acid, gelatin and the like are enumerated as materials that satisfy such a requirement. Both hyaluronic acid and gelatin are capable of being treated as viscous aqueous solutions and utilized as a gel by various processing methods. [0013] As these materials are extracted and purified from mainly the living body of an animal or the like, their good biocompatibility has already allowed them to be put to practical use in medical drugs and other various medical fields. Further, when the materials are implanted in a living body, gelatin or hyaluronic acid molecules are continuously released during decomposition and absorption processes, to exert viscosity and maintain the hydrophilic property. As a result, even if the materials are in contact with parts of the damaged or deficient tissues, they also have a characteristic to make it difficult to cause physically binding or adhesion. [0014] Exemplified as techniques to produce, by applying these characteristics, an adhesion-preventing membrane, medical material or the like utilizing hyaluronic acid are ones disclosed in Japanese Unexamined Patent Publication Nos.73103/1994 and Japanese Examined Patent Publication No. 30124/1995, Japanese Registered Patent No. 2670996, Japanese Unexamined Patent Publication Nos. 333402/1986 and 234864/1986, Japanese Registered Patent No. 2648308, Japanese Unexamined Patent Publication Nos. 157378/1996, 296005/1997, 102002/1995, and 509386/1995 and the like. However, a technique to provide not only an adhesion-preventing effect but also induction of tissue regeneration and mechanical strength sufficient to withstand suturing can not be found in the disclosed techniques, nor in other existing techniques. [0015] Examples of techniques that utilize gelatin with the expectation of an adhesion-preventing effect, as in the case where hyaluronic acid is used, include ones disclosed in Japanese Unexamined Patent Publication Nos. 103479/1997 and 52204/1996. However, similar to the technique using hyaluronic acid, neither of the techniques disclosed in these publications has succeeded in providing a medical material that can concurrently satisfy the three requirements consisting of adhesion-preventing effect, mechanical strength capable of suture fixation and guiding tissue regeneration. [0016] The term "suturable" in the present invention means such a state that a membrane can be fixed at a part of the membrane, for instance, two or more points thereof to an implanted part in a living body, for example, defective sites in the pericardium, cerebral dura mater, pleura, intestinal chorion and the like, or a resected part in the lungs, liver or the like, using a general suture thread for surgery. Further, it also means that the membrane can be maintained in a state that the membrane does not easily deviate, drop, or move from the suture-fixed position or deform for a certain period of time. [0017] The term "guided tissue regeneration" means that the adhesion-preventing membranes transplanted into defective sites in a tissue or organ have a property to induce regeneration of the tissue. Specifically, such property refers to a state that natural healing and a regeneration process take place smoothly without showing an inhibition of normal regeneration of body tissues, which is often observed when using an artificial composition such as a synthetic high molecular compound. [0018] The term "biocompatibility" in the present invention means the degree of immunological and histological reactions in a living body when an artificial product is implanted into the body and is determined by an inflammatory response or the like observed by the naked eye. [0019] The term "adhesion" means an agglutination or adhesion between organs or tissues that should be essentially separated from each other. This adhesion is determined by observation with the naked eye. Continue reading about Suturable adhesion-preventing membrane... Full patent description for Suturable adhesion-preventing membrane Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Suturable adhesion-preventing membrane patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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