Drug – bio-affecting and body treating compositions – Designated organic nonactive ingredient containing other... – Aftertreated solid synthetic organic polymer
Reexamination Certificate
2000-10-16
2004-02-24
Webman, Edward J. (Department: 1617)
Drug, bio-affecting and body treating compositions
Designated organic nonactive ingredient containing other...
Aftertreated solid synthetic organic polymer
C525S424000, C525S043000, C525S449000, C525S454000, C525S408000
Reexamination Certificate
active
06696499
ABSTRACT:
The present invention relates to the discovery that the use of biodegradable polymeric compositions can prevent or reduce communication between two sites after surgery and thereby significantly reduce and in some cases, actually prevent post-operative adhesions which often occur during the initial phases of post-surgical repair.
BACKGROUND OF THE INVENTION
A major clinical problem relating to surgical repair or inflammatory disease is adhesion which occurs during the initial phases of the healing process after surgery or disease. Adhesion is a condition which involves the formation of abnormal tissue linkages. These linkages which form can impair bodily function, produce infertility, obstruct the intestines and other portions of the gastrointestinal tract (bowel obstruction) and produce general discomfort, e.g. pelvic pain. The condition can be life threatening. The most common form of adhesion occurs after surgery as a result of trauma, although adhesion may occur as a result of other processes or events such as pelvic inflammatory disease, mechanical injury, radiation treatment and the presence of foreign material.
Various attempts have been made to prevent postoperative adhesions. For example, the use of peritoneal lavage, heparinized solutions, procoagulants, modification of surgical techniques such as the use of microscopic or laparoscopic surgical techniques, the elimination of talc from surgical gloves, the use of smaller sutures and the use of physical barriers (films, gels or solutions) aiming to minimize apposition of serosal surfaces, have all been attempted. Unfortunately, very limited success has been seen with these methods. Barrier materials, in various forms such as films and viscous intraperitoneal solutions, which are designed to limit tissue apposition, have also met with only limited success. The best of these barrier materials include cellulosic barriers, polytetrafluoroethylene materials, and dextran solutions. Also, a number of films based on polylactic acid, polyglycolic acid and copolymers of the two have proven to be unsuccessful. Indeed, most barrier materials have met with failure because these materials can induce untoward biological effects, e.g., foreign body reaction.
U.S. Pat. No. 5,410,016 to Hubbell, et al. is directed to photopolymerizable biodegradable gels for use as adhesion barriers, as control release systems for drugs, to provide temporary protection of tissue surfaces and for adhering or sealing tissues together. Hubbell, et al. discloses water-soluble macromonomers containing photopolymerizable groups on each end which are administered or placed on tissues prior to a photopolymerization step. After administration, the macromonomers are photopolymerized in situ in order to produce a crosslinked polymer on the tissue. The method of Hubbell, et al. suffers from the disadvantage that it is a cumbersome system, requiring additional equipment and expertise which adds to the cost of the treatment. In addition, the method suffers from the disadvantage that the patient must be irradiated with energy to polymerize the macromonomers during or after surgery, potentially compromising sterility and complicating and prolonging the surgical process. Given the nature of the system used to polymerize macromonomers, the Hubbel system produces polymers of high crosslink density which are somewhat weak in structure. In contrast to the polymers of Hubbell, the present invention makes use of polymers which are polymerized prior to use in the patient (“prepolymerized”).
Ideally, a physical barrier for adhesion prevention should be completely absorbable and nonreactive. In addition, it should stay in place in the body with a minimum of suturing or stapling.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide polymeric barriers which may be used to substantially prevent tissue to tissue adhesions and adhesions between tissue and implants and devices.
It is an additional object of the invention to provide polymeric materials in film, other solid structures such as rods, cylinders, porous structures such as foams, dispersions, viscous solutions, liquid polymers, sprays or gels which may be administered easily and with uniform results after surgery.
It is a further object of the invention to provide polymeric materials which may be used to substantially prevent adhesions and which may be effective for delivering bioactive agents.
It is yet an additional object of the invention to provide bioabsorbable polymeric materials which can be produced in a variety of formulations which have acceptable strength, are non-reactive with patient tissue and are bioabsorbable.
It is yet another object of the present invention to provide polymeric barriers which can be used in various forms, e.g., films, other structures such as rods and cylinders, foams, gels, dispersions, liquid polymers, sprays or viscous solutions, to provide flexibility in administration and use.
These and/or other objects of the invention may be readily gleaned from the detailed description of the present invention which follows.
SUMMARY OF THE INVENTION
The present invention relates to a method for eliminating or reducing post-surgical tissue adhesions using polymeric materials which are substantially integral and relatively rapidly bioabsorbable. It is the combination of these characteristics in polymers of the present invention which has produced favorable results in substantially reducing or even eliminating post-operative adhesions. Moreover, the method of the present invention is performed simply and in a cost-effective manner without the need for additional or expensive equipment. Unlike the prior art methods, the present invention is used under sterile conditions without exceptional efforts to maintain sterility and avoids the necessity of irradiating the patient. In addition, certain polymers used in the present invention (e.g. films or related preformed structures of polymer) exhibit sufficient strength and flexibility to be able to conform to a site to be protected and allow a suture to hold a polymer structure in place at the site of surgery.
It now has been discovered that the polymers according to the present invention, which are able to generate an integral barrier, are advantageously employed in reducing and even completely eliminating post-surgical adhesions. The present method comprises administering or affixing to an area in a patient's body at risk for developing adhesions, a polymeric composition comprising AB diblocks (preferably, as di-diblocks, as discussed in greater detail herein) or ABA triblocks which are chain-extended, coupled and/or crosslinked. Preferably, the A blocks comprise aliphatic ester units, more preferably derived from hydroxy acid units or their cyclic dimers and the like, even more preferably &agr;-hydroxy acid units. In many embodiments, the method comprises administering the instant polymer compositions to a site within the patient's body which has been subjected to surgical repair or excision. In the present invention, the polymeric material provides a barrier to prevent adhesions from forming. After this period of protection, the polymer will degrade and will be resorbed within the patient's body and/or excreted from the patient's body. According to the present method, problems associated with non-absorbtion or foreign body reactions are significantly reduced or prevented.
The polymer may be administered in various forms such as films, other structures including rods, cylinders, foams, dispersions, viscous solutions, liquid polymers, sprays or gels. The form a polymer takes at the surgical site will depend upon the type of surgery which has been performed or the condition which is to be treated and the site to be treated. In addition, the need to deliver the polymer to a particular site within the body may be determinitive of the form in which the polymer is delivered. The present method may be used after virtually any surgery to prevent tissue adhesion which occurs during the initial phases of post-surgical repai
Cohn Daniel
Hotovely Anna
Pines Eli
Coleman Henry D.
Life Medical Sciences, Inc.
Sapone William J.
Sudol R. Neil
Webman Edward J.
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