KR20020012170A - Compositions of polyacids and polyethers and methods for their use in reducing adhesions - Google Patents

Abstract

The present invention is directed to bioadhesive, bioresorbable, anti-adhesive compositions prepared from macromolecular complexes of carboxyl group-containing polysaccharides, polyethers, polyacids, polyalkylene oxides, polyvalent cations and / or polyvalent cations. It relates to improved methods of making and using. The polymers are connected to each other and dried with a membrane or sponge, or used as fluids or microspheres. Bioresorption, bioadhesion, and anti-adhesion compositions are useful in surgery by inhibiting the formation and remodeling of postoperative adhesions. The composition is designed to degrade in vivo and thus can be removed in the body. The membrane is inserted during drying or optionally after conditioning in aqueous solution. The bio-adhesion, bioadhesion, bioresorption, antithrombogen and physiological properties of these membranes and gels may be used in the careful control of the pH and / or cation content of polymer casting solutions, polyacid compositions, polyalkyrene oxides or for use in surgery. It may be varied as required by the conditioning of the membrane. Multilayer membranes can be prepared and used to provide further control over the physiological and biological properties of anti-adhesion membranes. The antiadhesive compositions are also used for drug delivery and local release to lubricating tissues and / or medical instruments, and / or surgical sites.

Description

COMPOSITIONS OF POLYACIDS AND POLYETHERS AND METHODS FOR THEIR USE IN REDUCING ADHESIONS

Related Applications

This application claims priority based on US Provisional Patent Application No. 60 / 127,571, filed April 2, 1999 and US Utility Model Application No. 09 / 472,110, filed December 27, 1999.

Adhesion is undesirable growth of tissue that occurs between layers of adjacent biological tissue or between tissues and internal organs. Adhesions are typically formed during a wound healing after surgery, where adhesions can interfere with the normal activity of the tissues and organs on adjacent structures.

The medical and scientific community has been studying how to reduce postoperative adhesion formation using high molecular weight carboxy containing biopolymers. The biopolymer can form a hydrated gel that acts as a physical barrier that separates the tissues from each other so that no wound is formed, so that no adhesion is formed between normal adjacent structures. After the wound is sufficiently healed, the barrier is no longer needed and must be removed from the living body so that the affected tissue can function normally.

Various types of biopolymers are used for this purpose. For example, Balazs et al. Disclose a method of using fragments of hyaluronic acid (HA) to prevent adhesions in US Pat. No. 4,141,973. However, HA has a relatively short half-life in vivo from 1 to 3 days due to its relative solubility and easily degraded properties in vivo, which limits its effectiveness as an anti-adhesion agent.

Methyl cellulose and methyl cellulose derivatives are also known to reduce adhesion and scar formation that may occur after surgery (Thomas E. Elkins, et al., Adhesion Prevention by Solutions of Sodium Carboxymethylcellulose in the Rat, Part I , Fertility and Sterility, Vol 41, No. 6, June 1984; Thomas E. Elkins, MD et al., Adhesion Prevention by Solutions of Sodium Carboxymethylcellulose in the Rat, Part II , Fertility and Sterility, Vol. 41, No. 6, June 1984). However, the solution is quickly reabsorbed by the living body and disappears from the surgical area.

In addition, polyether solutions can also reduce postoperative adhesion. US Pat. No. 4,993,585 to Pennel et al. Discloses the use of solutions containing up to 15% polyethylene oxide to reduce postoperative adhesion formation. Pennel et al. Disclose in US Pat. No. 5,156,839 the use of physiologically acceptable neutral pH mixtures containing up to 2.5% by weight of carboxymethylcellulose and up to 0.5% by weight of polyethylene oxide. Since the pH is neutral, the material does not form a binding complex and, therefore, is soluble and is removed from the living body within a short time.

Since the solution has a short stay in vivo, it may have the disadvantage that it cannot remain at the surgical site for a sufficient time to achieve the desired antiadhesion effect. Thus, anti-adhesion membranes using specific polymers have been made.

Although certain carboxypolysaccharide containing membranes have been disclosed, conventional membranes may have drawbacks for use to prevent coalescence under certain conditions. Butler's U.S. Pat.No. 3,064,313 discloses 100% carboxymethylcellulose having a degree of substitution of 0.5 or less by making the film insoluble by acidifying the pH of the solution to 3-5 and then drying the mixture at 70 ° C. Disclosed is a method for producing a film of CMC). These films are not designed to be used as anti-adhesion barriers.

Anderson discloses a film composed of 100% carboxymethylcellulose with molybethylene oxide, alkali metal salts, and plasticizers for external bandage use in US Pat. No. 3,328,259. The materials are readily soluble in plasma and water, so the residence time as a complete film will be very short. Therefore, this composition is not suitable for alleviating postoperative adhesions. Smith et al., US Pat. No. 3,387,061, disclose an insoluble binding complex of carboxymethylcellulose and polyethylene oxide prepared by lowering the pH to 3.5 or below, preferably 3.0 or below, followed by drying and baking the precipitate obtained ( See Example 38). This membrane is not intended as a surgical operation to relieve adhesion. The membrane is also insoluble, too stiff, and does not swell as moderately as to prevent postoperative adhesion.

Burns et al. Disclose in US Pat. No. 5,017,229 a film insoluble in water made of hyaluronic acid, carboxymethyl cellulose and a chemical crosslinker. Because of the covalent crosslinking with carbodiimide, the film requires an extensive cleaning process to remove excess crosslinking agent, and because it is made without plasticizer, it is too hard and brittle to use to prevent adhesion. That is, they do not easily adapt to the shape of tissues and organs of the living body.

Thus, there is a need for anti-adhesion membranes and gels that can be used under a variety of circumstances. D. Wiseman overviews the prior art in the field of Polymers for the Presention of Surgical Adhesions in Polymeric Site-specific Pharmacotherapy (AJ Domb, Ed. Wiley & Sons, (1994)). Currently available anti-adhesion gels are made of ionic crosslinked hyaluronic acid (Huang et al., US Pat. No. 5,532,221, incorporated herein by reference).

Ion crosslinking of polysaccharides is described in the chemical and patent literature (Morris and Norton, Polysaccharide Aggregation in Solutions and Gels , Chapter 19 in Aggregation Processes in Solution, Wyn-Jones, E. and Gormally, J, Eds., Elsevier Sci. Publ). Co. NY (1983). Each type of metal ion can be used to form gels of different polymers under specific conditions of pH, ionic strength, ion concentration, and polymer composition. For example, alginate (linear 1,4-cross β-D-mannuronic acid, α-L-glucuronic acid polysaccharide) has a structure in which divalent calcium ions are bonded and It is possible to form a binding structure between polyglucuronate sequences that can induce gel formation. Similar calcium binding capacity is also demonstrated by pectin with poly-D-galacturonate sequence. The order of selectivity of the cation for pectin is Ba ²⁺ > Sr ²⁺ > Ca ²⁺ . CMC can also bind monovalent and divalent cations, and CMC solutions can form gels by the addition of certain trivalent cations ( Cellulose Gum , Jercules, Inc., p. 23 (1094)).

Sayce et al. Disclose air freshner gels comprising CMC and trivalent cations such as chromium or aluminum (US Pat. No. 3,969,290).

Smith discloses a synthetic surgical suture made of a metal salt of cellulose ether insoluble in water (US Pat. No. 3,757,786).

Shimizu et al. Disclose hydrogels composed of water-soluble polymers such as dextran and cystine or lysine and starch complexed via polyvalent cations (US Pat. No. 4,024,073).

Mason et al. Disclose CMC- and arabic rubber aluminum hydrogels used as phosphate binders in the treatment of hyperphosphatemia (US Pat. No. 4,121,719).

US 5,266,326 discloses insoluble alginate gels made of calcium chloride.

Anti-adhesion gels are made of ionic crosslinked hyaluronic acid (Huang et al., US Pat. No. 5,532,221). Crosslinking is made by including polyvalent cations such as iron, aluminum or chromium salts. Hyaluronic acid (obtained naturally or biotechnologically) is quite expensive.

Thus, the prior art does not disclose the membranes or gels of the present invention suitable for various surgical uses.

Pennell et al. Disclose CMC solutions containing small amounts of high molecular weight PEO (US Pat. No. 5,156,839). In one embodiment Pennel discloses a covalent crosslinking gel using dimethylrollurea.

Accordingly, the present invention has various purposes.

It is a first object of the present invention to provide compositions and methods for reducing the occurrence of adhesion formation during and after surgery. This includes preventing the formation of de novo adhesions in primary or secondary surgery.

Another object of the present invention is to prevent adhesion remodeling after secondary surgery to remove novo adhesions produced after primary surgery.

Another object of the present invention is to provide a cheap anti-adhesion composition in which a dangerous wound remains at the surgical site during any initial stage.

It is another object of the present invention to provide an anti-adhesion membrane that can be easily hydrated in a controlled manner to form a complete hydrogel.

Another object of the present invention is to provide an anti-adhesion membrane with controlled bioresorbability.

An additional object of the present invention is to ensure that it is securely placed at the surgical site, which has good handling properties during the surgical procedure, is adaptable to the tissue, flexible, strong, easily molded on the tissue surface, and the tendency of adhesion formation is minimized. It is to provide an anti-adhesion membrane with sufficient bioadhesion to the extent possible.

Another object of the present invention is to provide an anti-adhesion membrane that has the desirable properties of a drug incorporated into the membrane, thereby allowing the drug to be delivered locally to the surgical site for a period of time.

It is another object of the present invention to provide a gel composition having improved viscosity and elasticity, anti-adhesion, coatability, tissue adhesion, anti-thrombogen or bioresorbability.

It is another object of the present invention to provide a combined membrane / gel composition having improved anti-adhesion properties.

In order to achieve the above object, in one embodiment of the present invention, by closely controlling the amount of carboxy residue and polyether in the pH, the carboxypolysaccharide / polyether bond complex, by closely controlling the bond between the polymers, The properties of the anti-adhesion membrane can be carefully controlled. By closely controlling the degree of intermolecular bonding and the amount of polyether, we can closely change the physical properties of the membrane, thus optimizing the anti-adhesion, bio-adhesion, bio-resorbability and anti-thrombogen properties of the membrane Enable to achieve treatment results.

In another embodiment of the present invention, polyvalent cations comprising Fe ³⁺ , Al ³⁺ and Ca ²⁺ , and / or poly cations including polylysine, polyarginine and the like may be used to provide intermolecular attraction. Thus, gels with improved viscosity can be provided.

Excessive hydration can lead to a "loose gel" which may not stay in position or disintegrate by irreversible conversion of the membrane. In addition, excessive swelling can result in excessively high hydrostatic pressure, adversely affecting tissue and organ function. The membrane must be physiologically acceptable, flexible, have a desirable degree of bioresorbability and a desirable degree of antithrombogenity, and be biologically inert.

Summary of the Invention

A first aspect of the present invention includes macromolecular bonds of, such as carboxypolysaccharides (CPS) and polyethers (PE), such as polyethylene glycol ("PEG"), useful for inhibiting postoperative adhesions. Composition. Another aspect of the invention involves a process for preparing a complex of CPS and PE that can exhibit desirable physical and biological properties.

The preparation of membrane-like composites with desirable properties is accomplished by varying the degree of bonding between the polymers. This change in properties can be attributed to the pH of the casting solution (hereinafter referred to as "membrane pH"), the molecular weight of the polymer, the percent composition of the polymer mixture, and / or the degree of substitution (ds) by the carboxy moiety in the CPS, and the polyvalent cations and / or Or by changing the presence and concentration of poly cations. Further changes in membrane properties are achieved by adjusting the membrane after initial manufacture. Multilayer membranes with other layers selected to exhibit other properties are also an aspect of the present invention.

In order to solve the problems of conventional anti-adhesion compositions, we propose a novel anti-adhesion gel based on bond complexation between ionic bond polyacid ("PA") and hydrophilic polyalkylene oxide ("PO"). Developed. The PA of the present invention can be prepared from polyacrylic acid, carboxypolysaccharides such as CMC, and other known polyacids. Ion crosslinking gels of the present invention can be prepared by mixing polyacids and other polyethers together in a dried form or in the form of an aqueous solution and then providing a crosslink between PA, PO and cations by adding a solution containing a cation. have. In certain embodiments, the pH of the mixture may be adjusted to provide some degree of direct complexation between PA and PO so that a composition can be obtained that can be bound by hydrogen bonding and ionic bonding. The pH and / or osmotic pressure of the composition can then be adjusted to be physiologically acceptable. The gel can then be sterilized and stored before use.

The membranes and gels of the present invention can be used to inhibit postoperative adhesions, reduce the incidence of arthritis, and / or provide various medical and / or veterinary lubricants.

Additionally, in some aspects of the invention, drugs may be included in the membrane or gel to deliver the pharmaceutical compound directly to the tissue.

In certain embodiments, the compositions can be sterilized using heat treatment methods, gamma irradiation and ion beams that can modify the physical and other properties of each component. In another embodiment of the invention alternatively, the material may be filtered sterilized.

The material is biocompatible and can be removed from the living body within a desired period of time that can be controlled.

Unlike the prior art, anti-adhesion compositions can be prepared to have desirable properties. Furthermore, conditioning the anti-adhesion membrane after manufacture may result in unexpected properties that bring certain desired benefits.

Improved anti-adhesion properties can be achieved by using both gel and membrane compositions together in the course of treatment.

Prior to describing the present invention in detail, the following terms used herein are defined.

The term "adhesion" refers to abnormal attachment between tissues and organs formed after inflammatory stimuli such as surgical trauma.

The terms "adhesion prevention" and "anti-adhesion" are used to prevent or inhibit postoperative scar formation and the formation of fibrous bands between wounded tissue and between wounded and unwounded tissue. Means that.

The term "association complex" or "intermacromolecular complex" is a molecular network formed between CPS, polyacid, PE, polyalkylene oxide and / or polyvalent ions, the network comprising hydrogen and And / or are cross-linked via ionic bonds.

The term "bioadhesive" means that it can stick to living tissue.

The term "bioresorbable" means that it can be resorbed and removed from a living body.

The term "biocompatible" means physiologically acceptable to living tissues and organisms.

The term "carboxymethylcellulose" ("CMC") consists of repeating carboxylated cellulose units, and additionally two anhydroglucose units (β-glucopyrano) linked by 1,4-glucoside linkages. It is meant a polymer consisting of a) (OS residues).

The term "carboxypolysaccharide" ("CPS") consists of one or more repeating monosaccharide units, meaning a polymer having a hydroxy residue in which at least one monosaccharide unit is substituted with a carboxy residue.

The term "chemical gel" refers to a gel network comprising a covalent crosslinked polymer.

The term "degree of substition" ("d.s.") refers to the average number of carboxy or other anionic moieties present per mole of cellobiose or other polymer.

The term "discectomy" refers to surgery to remove a ruptured vertebral disc.

The term "endoscope" refers to an optical fiber device for close observation of tissue in vivo, such as, for example, laparoscopy or arthroscopy.

The term "fibrous tissue" refers to scarring or adhesions.

The term "gel pH" refers to the pH of a gel or the pH of a casting solution, from which a gel in gel or partially dried form is formed.

The term "hyaluronic acid" ("HA") refers to an anionic polysaccharide composed of repeating disaccharide units of N-acetylglucosamine and glucuronic acid.

The term "hydration" (also "swelling") refers to the process by which the solvent is absorbed by the polymer solution.

The term "hydration ration" (also the same as "swelling ration") limits the dry weight to the wet weight of the hydrated membrane, sponge or microsphere, then divides by 100 by the dry weight. It means multiplied.

The term "hydrogel" refers to a three-dimensional network of hydrophilic polymers present in large quantities of water.

The term "laminectomy" refers to a surgical procedure that removes one or more spinal plates.

The term "laparoscope" refers to a small diameter scope used to insert through a punctured wound in the abdomen and allow the inside to be seen during a minimally invasive surgical procedure. It means.

The term "membrane pH" refers to the pH of the casting solution, from which the membrane is made.

The term "mesothelium" refers to the epithelium lining the pleural, pericardial and peritoneal cavities.

The term "peritoneum" refers to the intestinal membrane lining the abdominal cavity and surrounding the organs.

The terms "physical gel", "physical network" and "pseudo gel" refer to a non-covalent cross-linked polymer network, in which the binding of the polymer in the gel is relatively weak and potentially reversible chain-chain interactions. These bonds mean hydrogen bonds, ionic associations, ionic bonding, hydrophobic interactions, cross linking by crystalline fragments, and / or solvent complexation.

The term "polyacid" refers to a molecule comprising a subunit with acidic groups that can be dissociated.

"Polyalkylene oxide" ("PO") means a non-ionic polymer comprising an alkylene oxide monomer. Examples of polyalkylene oxides include polyethylene copolymers (PEO), polypropylene oxide (PPO) and polyethylene glycol (PEG), or block copolymers comprising PO and / or PPO.

The term "polycation" refers to a polymer containing a positively charged portion.

The term "polyethylene glycol" ("PEG") refers to a nonionic polyether polymer consisting of ethylene oxide monomers and having a molecular weight range of about 200 daltons ("d") to about 5000 daltons. .

The term "polyethylene oxide" ("PEO") refers to a nonionic polyether polymer composed of ethylene oxide monomers. The molecular weight of PEO used in the present invention is 5,000 to 8,000 kilodaltons ("kd").

The term "solid" as used in connection with a polymer composition refers to the weight percent of the total polymer content relative to the total weight of the composition.

The term "solid ratio" refers to the percentage of the total amount of dry polymer, expressed in weight percent relative to the total solids content.

The term "tissue ischemia" refers to the loss of blood flow in living tissue.

Certain embodiments of the present invention are bioresorbable carboxypolysaccharides (CPS), polyimplantable and implantable in wounds or tissues that reduce adhesion formation during and after surgery, and / or in the process of wound healing. Compositions and methods comprising delivering a binding complex consisting of an acid (PA), polyalkylene oxide (PO), polyether (PE), polyethylene glycol (PEG), and / or polyvalent ions and / or poly cations It is about. Complexes in the form of membranes are generally mixed with an appropriate amount and composition of CPS and PE in a solution, and then optionally acidified to a desired pH to form an acidic binding complex, and then, if necessary, the solution is Prepared by pouring into a plane and drying the mixture under reduced pressure (> 0.01 Torr) or atmospheric pressure (about 760 Torr) to form a membrane. The connective complex is placed between tissues while the wound is healed. Failure to do so tends to form coalescences between them. The complexes remain in the site for different times depending on their composition, preparation method, and control after preparation. When the tissue is sufficiently healed, the complex is broken down and / or dissolved to remove it from the living body.

I. Membrane

Membranes according to the invention can be prepared to have the required degree of stiffness, different degrees of bioresorption, different degrees of bioadhesion, different degrees of antiadhesion efficacy, and different degrees of antithrombogen properties.

A. Association Complexation

The exact mechanism of bond complex production between CPS and PE is not fully known, but one theory is that hydrogen bonds can be produced between the carboxy moiety of the polysaccharide and the ether oxygen atoms of the polyether. See Industrial and Engineering Chemistry 45 (10): 2287-2290 (1953) by Dieckman et al. 1 illustrates this theory. The pH of the polymer solution, from which the membrane is cast, is carefully titrated to acidic pH using a suitable acid. The initial neutral, anionic saccharide carboxyl group is protonated to the free carboxylic acid by the addition of an acid (eg hydrochloric acid) to the mixed polymer casting solution. The protonated carboxy moiety then electrostatically binds to the ether oxygen atoms of the polyether to form hydrogen bonds in the form of dipole-dipole interactions.

Reducing the pH of the casting solution increases the number of protonated carboxy residues, which increases the likelihood of generating hydrogen bonds with the polyether. This enhances the polymer network, resulting in a membrane that is stronger, longer lasting, less soluble and less bioresorbable. On the other hand, when the pH of the casting solution is close to neutral, the carboxyl groups on the carboxypolysaccharides are more negatively charged, thus pushing the oxygen oxygen atoms of each and PE together, resulting in weak hydrogen bonds with low or no structural integrity. A gel is obtained.

For the sake of explanation, three interactions are distinguished as shown in FIG. The figure shows an illustration of possible intermolecular complexation in which the four carboxymethyl groups of the carboxypolysaccharide (CPS) chain line up opposite the four ether oxygen atoms of the polyether (PE) chain. 1A shows a situation that may occur at a pH of about 7. At neutral pH the carboxy moiety dissociates and thus no hydrogen bond complex is formed between the ether oxygen atom of PE and the positively charged carboxymethyl group of CPS. 1B shows a situation that may occur at a pH of about 2. At low pH, most of the carboxy moieties are protonated and, therefore, most are hydrogen-bonded with ether oxygen atoms of PE. 1C shows a situation that may occur at a pH of about 3-5. At pK _a of CPS, which is about 4.4, half of the carboxyl is protonated, thus the ether oxygen atom of the corresponding PE is hydrogen bonded. Within this intermediate pH range the degree of crosslinking can be closely controlled in accordance with the present invention (FIG. 2).

The membrane prepared according to FIG. 1B is similar to that disclosed by Smith et al. (1968). They do not have the important properties of an ideal anti-adhesion membrane. Low pH membranes do not hydrate well. Furthermore, they are poor in touch, not flexible, and have low solubility. They are insoluble and therefore cannot be removed from the bior in a sufficiently short time. In addition, the acidity of the casting solution is high so that a relatively large amount of acid is transferred to the tissue compared to the membrane of neutral pH. Physiological membranes are difficult to neutralize the acid load before tissue damage occurs. Thus, they have insufficient biocompatibility.

Compared to the conventional membrane described above, the present invention teaches an anti-adhesion membrane such as the one illustrated in FIG. 1C. Since such membranes are prepared in the intermediate pH range, typically between about 3 and 5, the amount of crosslinks is not too high and not too small to disintegrate too quickly so that they do not dissolve quickly enough in the composite. In addition, the rheological properties can be changed by changing the pH of the casting solution (Table 1) and the physical properties of the membranes prepared from the solution can be changed (Table 2).

The mechanism for the formation of binding complexes is not essential to the invention. Our findings regarding CPS and PE fully illustrate the invention without the support of other specific theories of binding between each component.

FIELD OF THE INVENTION The present invention relates generally to the manufacture and use of membranes comprising crosslinked gels comprising carboxypolysaccharide / polyether macromolecular complexes, polyacids, polyalkylene oxides and polyvalent ions Includes the use of membranes and gels to prevent adhesion formation between tissues after surgery, trauma and / or disease progression. The properties of the composition can be adjusted to have the necessary degree of anti-adhesion, bioresorbability, bioadhesiveness and antithrombogen effect.

1 illustrates the theory of bond complex formation between carboxypolysaccharides and polyethers formed by hydrogen bonding at various pHs.

Figure 2 shows the results of a pH titration test of a solution prepared for CMC- and polyethylene oxide (PEO) -containing membrane casting.

FIG. 3 shows over time the hydration or swelling of CMC / PEO membranes prepared from casting solutions at room temperature and various pHs from 2.0 to 4.31.

4 shows hydration or swelling of CMC / PEO membranes in phosphate buffered saline (PBS) solution at pH 7.4 at room temperature.

5 shows solubility of membranes in PBS solutions of different compositions and pHs.

Figure 6 shows the results of examining the acidification of the PBS solution by the CMC / PEO membrane.

7 shows the effect of changing the molecular weight of PEO on the hydration or expansion of the CMC / PEO membrane.

8A-8B show the effect of changing the pH of the CMC / PEO solution of various compositions on the viscosity of the solution.

9A and 9B contain a total amount of solids of 1.33% and a CMC: PEO ratio of 50:50 of PEO with molecular weights of 4.4 Md (FIG. 9 a) and 500 kd (FIG. 9 b) measured with a nephelometry device. It shows the effect of the pH of the solution on the turbidity (turbidity) of the solution containing.

FIG. 10 shows the effect of pH on the full spectral absorbance (•) and forward scan turbidity (Δ), measured by the Nefelomatri device, of the solution described in FIG.

11A-11B show the effect of pH on the hydration of CMC / PEO membranes with compositions of 77.5% / 22.5%, 4.4 Md PEO, 50% / 50%, 4.4 Md PEO, and 50% / 50%, 300 kd PEO, respectively. To show.

11A shows the results at a pH of about 1.3 to about 4.2.

FIG. 11B shows the results of performing the same irradiation as in FIG. 11A at a pH of 1.3 to about 3. FIG.

Figure 12 shows the relationship between the pH of the solution and the solubility of the CMC / PEO membrane with the indicated composition.

FIG. 13A shows the relationship between the pH of the solution and the bioadhesion of the CMC / PEO membrane with the indicated composition.

FIG. 13B shows average data on the relationship between pH and bioadhesiveness of 77.5% CMC membranes.

14A-14B show scanning electron microscope (SEM) of the surface and cross section of a bilayer membrane consisting of irradiated 95% CMC / 5% PEO, pH 5 and 60% CMC / 40% PEO, pH 3 Each picture is shown.

15A-15B show SEM images of the surface and cross section of the irradiated 60% CMC / 40% PEO membrane, respectively.

16A-16B show SEM images of the surface and cross-section of a 95% CMC / 5% PEO, pH 5 and 60% CMC / 40% PEO, pH 3 membrane as in non-irradiated FIGS. 14A-14B. To show.

17A-17B show SEM pictures of the surface and cross-section of a 60% CMC / 40% PEO membrane as in unirradiated 15A-15B.

18A-18B show SEM images of the surface and cross-section of the irradiated singlet 77.5% CMC / 22.5% PEO membrane, respectively.

19A-19B show SEM images of the unirradiated membrane as in FIGS. 18A-18B.

20A-20B show SEM images of the surface and cross section of 100% CMC membrane, respectively.

FIG. 21 illustrates the relationship between the CMC / PEO ratio, the molecular weight of PEO and the total solid composition for the viscosity of ionic crosslinking in accordance with one embodiment of the present invention.

FIG. 22 illustrates the relationship between CMC / PEO ratio, percent solid composition and viscosity of ionic crosslinked gels in accordance with embodiments of the present invention.

FIG. 23 shows the relationship between% ionic bond of CMC / PEO gel, ionic composition and viscosity of autoclaved gel of embodiments of the present invention.

FIG. 24 depicts the relationship between% ionic bond, Cation composition and viscosity of non-autoclaved gels of CMC / PEO gels of embodiments of the present invention.

25A-25B show the effect of γ-ray irradiation on the molecular weight of the CMC / PEO component of the present invention.

25A shows the effect of γ-ray irradiation on the CMC / PEO membrane.

FIG. 25B shows the effect of γ-ray irradiation on CMC and PEO standards.

FIG. 25C shows the effect of γ-ray irradiation and autoclaved on CMC and PEO casting solutions.

Membranes prepared from CPS / PE casting solutions only require that they can easily handle CPS and PE solutions. CPS diluents (up to about 10% weight / volume) are easy to handle and about 2% CPS solutions are more manageable. Up to about 20% (weight / volume) of PEO solution can be prepared and handled, and about 1% by weight solution is easy to handle.

B. Carboxy Polysaccharides

Carboxypolysaccharides include carboxymethyl cellulose (CMC), carboxyethyl cellulose, chitin, carboxymethyl chitin, hyaluronic acid, alginate, pectin, carboxymethyl dextran, carboxymethyl chitosan, and glucosaminoglycans such as heparin, heparin sulphate Pate, and any biocompatible sort, including, but not limited to, chondroitin sulfate. Other suitable CPSs include polyuronic acids, polymannuronic acid, poly glucuronic acid, and polygururonic acid and propylene glycol alginate. Alternatively, carboxymethyl cellulose or carboxyethyl cellulose are used. In another embodiment, carboxymethyl cellulose (CMC) is used. The molecular weight of the carboxysaccharides can vary from 100 kd to 10,000 kd. CPSs in the 600 kd to 1000 kd range work well, and 700 kd CPS works well and is easily obtained commercially. The degree of substitution (d.s.) may be greater than 0 and up to 3 for the CMC. For other CPS, d.s. may be greater than zero and up to d.s. for a particular CPS.

C. Polyether and Polyethylene Glycol

Similarly, the polyethers used are not very difficult. Polyether is suitable for the present invention is polyethylene oxide (PEO), while CMC sodium alone is used as an anti-adhesion barrier in gel formulations, while CMC / PEO compositions have specific properties useful for inhibiting adhesion.

Membranes made of CMC and PEO are more resilient than membranes made of hard and stiff CMC alone. Thus, manipulations were made during surgery to closely match the form required for tight adhesion to various tissues. In addition, the inclusion of PEO in the composite provides antithrombogen properties that inhibit adhesions that reduce membrane adhesion of blood proteins and platelets (M. Amiji, Biomaterial. 16: 593-599 (1995); Merill, EW, PEO and Blood Contact in Polyethylene Glycol Chemistry-Biotechnical and Biomedical Applications.Harris JM (ed), Plenum Press, NY, 1992; Chaikof et al., AICh E. Journal 36 (7) : 994-1002 (1990)). PEO containing membranes reduce the fibrin mass approaching the tissue surface more than membranes containing only CMC. Increasing flexibility without stretching the CMC / PEO membrane improves control of the membrane's properties during surgery. The molecular weight range of the polyethers used in the present invention is in the range of about 5 kd to 8000 kd. Polyethers in the range of 100 kd to 5000 kd have good function and are suitable for commercial use.

Polyethylene glycol (PEG) is a polymer similar to PEO except that the number of monomer units of the polymer is generally less than PEO. The molecular weight of PEG suitable for the present invention is about 200 d to 5 kd, or about 1000 to 4000 d, and in other embodiments about 2000 d.

In addition to PEO, plasticizers such as glycerol may be incorporated into the compositions of the present invention. Glycerol and other plasticizers enhance the flexibility of the membrane. Other plasticizers other than glycerol include ethanolamine, ethylene glycol, 1,2,6-hexaneethanol, mono-, di- and triacetin, 1,5-pentanediol, polyethylene glycol (PEG), propylene glycol and trimethyl Contains all propane. The glycerol content of the composition is about 0% to 30% by weight or more. In another embodiment, the content of glycerol is in the range of about 2-10%, and in yet another embodiment, it is about 2-5%. As the proportion of glycerol in the film increases, the film becomes more plastic, has a resilient structure, and feels softer than a film that does not contain glycerol. In one experiment, a membrane made of 30% glycol was placed on the skin and the glycerol incorporated therein The adhesion was similar to that of the control film which did not include. The incorporation of glycerol improves the operating characteristics and provides a membrane that is easy to roll, which can be applied using a specifically designed insertion device defined as a "Filmsert ™" device. A description of the film insert device can be found in a patent application co-pended by Oppelt et al. In 09 / 180,010, filed October 27, 1998, entitled "Laparoscopic Insertion and Deployment Device," which is hereby fully incorporated by reference. Related.

Changing the ratio of polysaccharide to polyether changes the viscosity and elastic properties (Tables 4 and 5) of the solution and provides distinct degrees of adhesion inhibition and antithrombotic effects. Increasing the percentage of CPS increases bioadhesion, but decreases the antithrombotic effect. On the other hand, increasing the percentage of PE increases the antithrombotic effect but decreases bioadhesion. The percentage of carboxypolysaccharides relative to the polyether should be 10 to 100% by weight, preferably 50 to 90% by weight, most preferably 90 to 95% by weight. Conversely, the percentage of polyethers should be 0 to 90%, preferably 5 to 50%, most preferably about 5 to 10%.

The physical properties of the bond complex between CPS and PE can be closely controlled by the strength of the bond. Reducing the pH of the binding complex increases the amount of hydrogen cross-linking. Similarly, increasing the degree of substitution of the carboxypolysaccharide in the membrane increases cross-linking in the binding complex at a given pH, thereby decreasing solubility and thus reducing the bioresorbability of the complex. Membranes prepared with low pH polymer solutions are generally hard and stiff and dissolve more slowly and thus have a longer residence time in tissue compared to membranes prepared from high pH solutions or hydrogels. Low pH polymer membranes are generally useful when tissues have long adhesion formation or are slowly treated. This can happen when the surgery is performed on ligaments and tendons, characteristically slowly treated tissue. Thus, long-lasting membranes can minimize the formation of adhesions between these tissues. However, low pH membranes tend to be rough on contact, easily crack when overlapped, and tend to break easily.

In contrast, membranes prepared from high pH solutions are more flexible and easier to use than membranes prepared from low pH solutions. They have better bioadhesion and faster biodegradability than membranes prepared at low pH, and are therefore more useful when the adhesion formation period is short. These membranes feel smooth, pliable, and can overlap without much cracking or breaking as compared to membranes prepared in low pH solutions.

The pH of the composition may be 1-7, optionally 2-7, 2.5-7 in other embodiments, 3-7 in other embodiments and 3.5-6.0 in other embodiments. For some uses, a pH of about 4.1 is preferred in view of the desired balance between bioadhesion, antiadhesion, bioresorption and bioavailability in the various uses contemplated herein.

D. Bioadhesion and Hydration

Bioadhesion is defined as the attachment of macromolecules to physiological tissues. Bioadhesion is important for inhibiting surgical adhesion since the potential barrier must not deviate from the surgical site after it is located there. Both CMC and PEO are individually bioadhesive (eg, Bottenberg et al. , J. Pharm. Pharmacol. 43: 457-464 (1991)). Like other polymers known to swell upon exposure to water, CMC / PEO membranes are also bioadhesive.

Hydration contributes to the bioadhesion of membranes (Gurney et al., Biomaterials 5: 336-340 (1984); Chen et al., Compositions Producing Adhesion Through Hydration, In: Adhesion in Biological Systems , RSManly (Ed.) Acad. Press NY (1970) , Chaper 10). A possible reason for explaining this phenomenon is that as hydration increases, more changes in CMC are revealed, and thus can be made available to bind tissue proteins. However, excessive hydration adversely affects bioadhesion. Thus, the means for controlling the bioadhesion of the membrane is to control its hydration properties.

The membrane of the present invention is rapidly hydrated in PBS solution (FIG. 2). This action is analogous to placing a membrane on moist tissue during surgery or treatment of a wound. Hydration of the membrane increases both the thickness of the barrier and its flexibility, thus allowing it to conform to the type of tissue in which the membrane detaches during the time of attachment. The preferred hydration rate (% increase in mass due to water absorption) that provides the desired adhesion inhibition is about 100% -4000%, optionally 500% -4000%, in other embodiments this ratio is 700% -3000 %, And in another embodiment, the preferred hydration rate for tackiness reduction is about 2000% (FIG. 4).

In addition to reducing the pH of the binding complex, macromolecular binding can be increased by using CPS with increased degree of carboxyl substitution. By increasing the concentration of carboxyl residues that can be quantized on CPS, it is possible to increase the possibility of forming hydrogen bonds even at relatively low pH. The degree of substitution of CPS must be greater than zero, ie there must be some carboxyl residues that can form hydrogen bonds. In theory, however, the upper limit is 3 for cellulose derivatives, where 3 moles of carboxyl residue may be present for each mole of saccharide. Thus, in the broadest application of the present invention comprising CPS as a polyacid, d.s. is greater than 0 and up to 3 and comprises 3. In other embodiments, the d.s. is between 0.3 and 2. CPSs with d.s. of 0.5 to 1.7 are well applied and CPSs with d.s. of about 0.65-1.45 are suitable and commercially available.

E. Bioresorption

The complexes of the present invention are intended to have a limited residence time in vivo. Once placed on the surgical or wound site, or site of inflammation, the dry film rapidly hydrates and turns into a gel-like sheet and is designed to act as a barrier for a limited time. When treatment occurs substantially, the anti-adhesive barrier naturally disintegrates and the components are removed from the body. In certain embodiments, the time to be removed from the body is only 29 days, since devices intended to remain in the body for more than 30 days must be regulated by the Food and Drug Administration. However, it may be desirable to provide long-lasting compositions for certain long-term use.

The bioresorption mechanism of the CMC / PEO complex is not well known. However, the initial stage of the bioresorption process is the dissolution of the CMC and PEO networks. Thus, increasing the solubility of the complex allows for easier removal of components from tissue (FIG. 5). Upon dissolution, CMC and PEO can circulate and diffuse and can be transported to the liver and kidneys, where they are metabolized or otherwise released from the body. In addition, enzymatic action can degrade carbohydrates. Enzymes contained in neutrophils and other inflammatory cells can break down the polymer network and thereby increase the removal rate of components from the body.

The rate of decomposition and dissolution and disintegration of the membrane is manipulated by carefully adjusting the pH during the formation of the binding complex, varying the CPS / PE ratio, selecting the appropriate degree of substitution of CPS and the molecular weight of PE and CPS. Reducing the molecular weight of CPS increases solubility (Kulicke et al., Polymer 37 (13) : 2723-2731 (1996)). The strength of the membrane can be tailored to the surgical application. For example, certain surgical applications (eg, spine or tendon) will require stronger and more durable membranes than others (eg, intraperitoneal application). By manipulating the above-mentioned experimental variety, it is possible to prepare and use products with various residence times in the body.

F. Bioavailability

The bioavailability of the CPS / PE complex of the present invention may depend on its acidity. Highly acidic complexes impart relatively more total acid load to tissues than neutral complexes. In addition, the faster the hydrogen ions dissociate from the complex, the faster the physiological mechanism must compensate for the acid load by buffering, dilution and other mechanisms. Modeling the proportion and total amount of acid given by the membrane in vivo, the membrane is placed in a PBS solution and the degree of oxidation of PBS is measured. In addition to the pH of the membrane, the composition of the membrane also affects the acid load carried to the body. 6 and Tables 3 and 6 show the results of studies designed to transport acids to tissues by membranes.

After making these, the membranes may be modified to suit the specific needs of the user. For example, relatively high bioresorbable membranes are more insoluble by “acidic” treatments, which are treated with solutions containing acids, such as, but not limited to, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid or nitric acid, and the like. It can be mad.

Conversely, relatively non-resorbable acidic membranes can be controlled by alkali ("alkaline" treatment) such as ammonia or by buffer solutions ("buffer" treatment) such as phosphate buffer (PB) or phosphate buffered saline (PBS). It may be made to be more bioresorbable and biobindable. PBS 10 mM solution at pH 7.4 is preferred because of the biocompatibility of the phosphate buffer. In addition, the pH of the membrane may be buffered without losing the advantages of the membranes made at low pH. Thus, even if its pH is raised by alkali or buffer treatment, the initial acidic membrane will slowly hydrate and have a relatively long residence time.

Table 7 below shows the effect of ammonia treatment on the properties of CMC / PEO membranes. The high acidic original membrane (pH 2.03) acidified the PBS buffer solution, initially pH 7.40, by lowering its pH to 4.33. After soaking in the PBS solution, the membrane was hydrated to more than 2.5 times its original dry weight, and after 4 days in PBS, the membrane lost about 29% of its original weight. In the same membrane, incubation for 1 min in 0.5 N ammonia solution substantially neutralized the membrane to release some hydrogen ions into the buffer solution, leaving the pH of the PBS solution almost neutral (pH 7.29).

Table 8 below shows the effect of phosphate-buffer treatment on the properties of CMC / PEO membranes. Membranes treated with 50 mM phosphate buffer solution for progressively longer time had more and more neutral pH as judged by reduced acid release into PBS solution. Likewise, PBS (10 mM phosphate buffer) neutralized the acid in the membrane (Table 9). Thus, the membranes can be made physiologically suitable for tissue and, moreover, because they are prepared at the acidic initial pH to produce the binding complex, these membranes retain the desired properties of the original complex.

G. multilayered membrane

In addition, multilayered membranes may be made that can be combined with a low pH inner membrane surrounded by, for example, an outer membrane made of high PH. This composition can introduce a membrane that minimizes the side effects of low pH membranes, while at the same time long term stability and low bioresorbability of the inner membrane. Moreover, the high pH outer portion is more bioactive than the low pH membranes, leaving these membranes more stable at that site.

Multilayered membranes may also be prepared comprising pure CPS or PE membrane as one layer. Such membranes may have soluble properties on the side of the mixture of CPS and PE, and anti-adhesion, elasticity, and properties of pure materials on the other side. For example, biocompatibility is a property of CPS, and pure CPS will have a high degree of biocompatibility. Alternatively, pure PE membranes will have the highest antithrombogen properties. Thus, the membrane can be made by combining the desired properties of each component.

Multilayered films can also be prepared in which the two layers have different ratios of CPS and PE. For example, in certain examples, the bilayered film has 97.5% CMC / 2.5% PEO on one side and 60% CMC / 40% PEO layer on the other.

The membranes of the present invention exhibit some desirable properties including, but not limited to, anti-adhesion, biobinding, anti-thrombogenogenic, and bioresorbability. The membranes of the invention are also elastic and can be inserted through the cannulae during a minimized open surgical procedure.

II. Ionically Cross-linked Polyacid / Polyalkylene Oxide Compositions

Other examples of the invention relate to ionic cross-linked gels to reduce surgical adhesions, reduce arthritis symptoms, and provide biocompatible lubricants. Methods for accomplishing these objectives include delivering implantable bioresorbable compositions containing polyethers and polyacids bound to each other by wounds or other biological sites by methods of ionic bonding, ionic association, or ionic cross-linking with one another. Consists of steps. Surprisingly, mixtures of polyethers, polyacids and ionic crosslinking agents have shown that the viscosity of this gel depends on the expected viscosity based on the interaction between polyethers and cross-linking ions, between polyacids and polyethers, or between polyacids and ions. It has been found that it can be raised to a high viscosity in comparison. Accordingly, the compositions of the present invention provide advantages not known in the previously disclosed anti-adhesive compositions.

Certain examples with relatively few intermolecular ionic bonds can be reabsorbed more slowly than those with more bonds. Thus, by increasing the intermolecular bonds, the in vivo residence time of the composition can be increased, thereby allowing the intermolecular bonds to remain in the site for longer periods of time than the smaller composition. For example, by selecting a composition that provides the highest viscosity (see below), the residence time can be adjusted to provide the desired lifetime of the antiadhesion effect. Additionally, in certain other examples, the compositions may be dried to produce a membrane from which may further increase the residence time at the tissue site. Thus, by selecting the chemical composition of the gel and selecting the form of the composition (eg gel or membrane), the desired combination of properties can be achieved according to specific requirements.

A. Gel Structure

Gels of the present invention are called "physical gels". Physics gels have been used to describe non-intrinsic cross-linked polymer networks (de Gennes, PG Scaling Concepts in Polymer Physics. Ithaca, NY Cornell University Press, p. 133, (1979)). Physical gels are distinguished from "chemical gels" which are covalently cross-linked. Physical gels have relatively weak and temporarily reversible chain-chain interactions that can consist of hydrogen bonds, ionic bonds, hydrophobic interactions, stereo-complex formation, cross-linking by crystal fractions, and / or solvent complexation. .

Ionic cross-linked gels can be prepared by mixing together appropriate amounts and compositions of polyacids, polyethers and cross-linkable cations in solution. Additionally and optionally, this solution is disclosed in US patent application Ser. No. 08 / 877,649, filed Jun. 17, 1997; US Pat. No. 5,906,997, now patented May 25, 1999; US patent application Ser. No. 09 / 023,267, filed February 23, 1998; US patent application Ser. No. 09 / 023,097; And US patent application Ser. No. 09 / 252,147, filed February 18, 1999; And as described for the carboxypolysaccharides and polyethers, it can be acidified to facilitate cross-linking of polyacid and polyether molecules via hydrogen bonding. Each patent application described above in this text is a reference to the present invention.

Ionic cross-linked gels are poured into a membrane form by pouring the solution into a suitable flat surface, such as a tray, and allowing the mixture to dry under reduced pressure (> 0.001 Torr) or under normal atmospheric pressure (about 760 Torr) to form a membrane. It can manufacture. In addition, sponges and microspehres of gel materials can be prepared. The ionic cross-linked binding complex will be placed between the tissues and will form an adhesion between them during healing of the wound. The complex may remain in the site for various periods of time depending on its composition, preparation method and post-preparation conditions. Once the tissues are substantially healed, the complex then degrades and / or dissolves and disappears in vivo.

Ionic cross-linked gels and membranes according to the present invention have a desired degree of viscosity, strength, varying proportions of biocompatibility, varying degrees of biocompatibility, varying degrees of anti-adhesion effects, and varying degrees of antithrombogen It can be prepared to have a characteristic.

Although the exact mechanism for the ionic cross-linking of the polyacid / polyether bond complex formation is not fully understood, one of the theories is that ionic bonds or associations are produced between the acid of the polyacid and the ether oxygen atoms of the polyether. . According to this theory, divalent ions such as calcium (Ca ²⁺ ), cobalt (Co ⁺⁺ ), magnesium (Mg ⁺⁺ ), manganese (Mn ⁺⁺ ), and iron (Fe ³⁺ ) and aluminum (Al) ^Trivalent ions, such as ³⁺ ), can be placed between the acid of the polyacid and the ether oxygen atom of the polyether, and can form ionic bonds by attracting valence electrons between the acid and the oxygen atom. According to this theory, since trivalent ions are trivalent, trivalent ions can provide tighter ionic bonds between the polymers of the solution. Additionally, cross-linking can occur between adjacent polyacid molecules, thereby allowing the polyether molecules to trap the polyether molecules without the need for direct polyacid / polyether association through ionic interactions. Can be. Cross-linking may also be achieved by using polyvalent cations such as polylysine, polyarginine or chitosan. However, the present invention is not based on any particular theory of operability.

Additionally, adjusting the pH of the solution can affect the degree of ionic bonds that can be produced between pH sensitive acidic groups and ether oxygen atoms. For example, when using a polyacid such as CMC, at a low pH, some carboxyl groups can be decomposed, and some carboxyl electrons can be used for ionic bonds to polyether oxygen atoms. In this situation, increased ionic bonding can be promoted by increasing the pH of the solution.

However, decreasing the pH may increase the degree of hydrogen bonding that may be produced between the polymers. See Industrial and Engineering Chemistry 45 (10): 2287-2290 (1953) by Dieckman et al. By adding an acid (eg hydrochloric acid) to the CPS solution, the neutral, anionic polysaccharide carboxyl group is initially converted to a free carboxylic acid group that is protonated. This protonated carboxyl group can then electrostatically bond with ether oxygen atoms of the polyether to form hydrogen bonds.

Reducing the pH of the polymer solution can increase the number of protonated carboxyl residues and increase the number of possible hydrogen bonds with the polyether. This may result in a composition that strengthens the polymer network, is stronger, more durable, and has less solubility and less bioresorbability. In another aspect, if the saik polymer solution is close to neutral pH, the carboxyl groups on the carboxypolysaccharide are more negatively charged, thus rejecting all of the ether oxygen atoms of the PE and each other, resulting in a gel of weak hydrogen bonds. do.

Thus, by using a combination of ionic cross-links and hydrogen bonds in combination, the gel of the present invention can be prepared to have particular desirable properties.

The above mechanisms for the formation of ionic cross-linked complexes are not an essential requirement of the present invention. The present invention is not based on any particular theory of binding between components.

Ionic cross-linked compositions of PA and PO are only necessary to ensure that solutions of PA and PO can be easily handled. Dilute solutions of CPS (up to about 10% weight / volume) are easy to handle and about 2% CPS solutions are easier to handle. Up to about 20% (weight / volume) of PEO solutions can be prepared and handled, and about 1% by weight of solution is easy to handle. However, if the molecular weight of the PE is reduced, the maximum concentration may be increased. By way of example only, PEG with a molecular weight of about 1000 Daltons may be prepared at a concentration of about 50%. In addition, by lowering the molecular weight of PE, higher concentrations that can be easily prepared and handled can be tolerated.

B. Multiacid Components

Polyacids can be of any biocompatibility type. For example, the polyacids useful in the present invention include glycosaminoglycans such as heparin, heparin sulfate and chondroitin sulfate, and carboxymethylcellulose (CMC), carboxyethyl cellulose, chitin, carbomethylmethyl chitin, hyaluronic acid, alginate, pectin, Carboxymethyl deck is a carboxypolysaccharide (CPS) like carboxymethyl chitosan. In addition, polyuronic acids such as polymannuronic acid, polyglucuronic acid, and polygluronic acid, and propylene glycol alginate may be used. Furthermore, polyacrylic acid, polyamino acid, polyacetic acid, polyglycolic acid, polymethacrylic acid, polyterephthalic acid, polyhydroxybutyl acid, polyphosphoric acid, polyterephthalic acid, polyhydroxybutyric acid, polyphosphoric acid, polystyrenesulfonic acid , And other biocompatible polyacids known in this distribution are suitable. Such polyacids are disclosed in Biodegradable Hydrogels for Drug Delivery, Park et al., Ed., Technomic Publishing Company, Basel, Switzerland (993), which are hereby incorporated by reference in their entirety. Preferably carboxymethylcellulose (CMC) is used. The molecular weight of the carboxypolysaccharides varies from 10 kd to 10,000 kd. CPS works well in the 600 kd to 1000 kd range, and 700 kd CPS is small in operation and easy to use commercially.

C. Polyalkylene Oxide Components

Likewise, many polyalkylene oxides can be used. These include polypropylene oxide (PPO), PEG, and block copolymers of PEI and PEO and PPO, such as Plurinics ™ (trade name of BASF Corporation, North Mount Olive, New Jersey). Preferred PO of the present invention is polyethylene oxide (PEO) having a molecular weight between dir 5,000 Daltons (d) and about 8,000 Kd. In addition, polyethylene glycol (PEG) having a molecular weight between about 200 d and about 5 kd is useful.

The inclusion of polyethers in the complex confers antithrombogenicity, which helps prevent adhesion by reducing the adhesion of blood proteins and platelets to the composition (M. Amiji, Biomaterials, 16: 593-599 (1995)). Merill, EW, PEO and Blood Contact in Polyethylene Glycol Chemistry-Biotechnicla and Biomedical Applications, Harris JM (ed), Plenum Press, NY, 1992; Chaikof et al., AI Ch. E. Journal 37 (7): 994- 1002 (1990). PEO-containing compositions damage the path of fibrin blood clots to tissue surfaces much more than compositions containing CMC alone. For one example of the invention in which the ion-complexed gels are dried to form membranes, sponges or microspheres, increasing the elasticity of the CMC / PEO composition without compromising tensile strength or elasticity may improve the handling characteristics of the composition during surgical treatment. Can be improved.

The inclusion of PE in the gel can also increase the coating or spreading performance of the gel on biological tissue. By increasing the spreadability, the gel can be used to coat more tissue more efficiently and so on, thereby allowing control of sites from damaged tissue to reduce adhesion formation and the like.

By varying the concentrations and ratios of polyacids, cationic polyvalent cations of polyethers and polyatoms can change the viscoelasticity of the solution and provide varying degrees of biocompatibility, anti-adhesion and antithrombogen effects. Increasing the percentage of polyacid can increase biobinding and reduce antithrombogen effect. In another aspect, increasing the percentage of PE increases antithrombogen effect and decreases biocompatibility. The percentage ratio of polyacid to PO may be about 10% to 99% by weight, or about 50% to 99% by weight, and in yet another example may be about 90% to about 99%. Conversely, in the case of POrk PE, the percent of PE can be from about 1% to 90%, or from about 1% to about 50%, and in another example, from about 1% to 10%. In another example, the amount of PE may be about 2.5%.

D. Ionic Components

The rigidity and thus the physical properties of the binding of the binding complex between PA and PO can be adjusted closely by selecting the appropriate polyvalent cation. In certain instances, using cations selected from groups 2, 8 or 13 of the periodic table It may be desirable. By increasing the concentration and / or valence of polyvalent cations, ionic bonds can be increased. Thus, trivalent ions of group 3 on the periodic table such as Fe ³⁺ , Al ³⁺ , Cr ³⁺ , are stronger ionic crosslinks than ions of group 2 such as Ca ²⁺ , Cr ³⁺ , or Zn ^2+. A binding complex may be provided. Such other cations can also be used to cross-link the gel polymer of the present invention. Polyvalent cations such as polylysine, polyarginine, chitosan, or other biocompatible polymers having net cationic charges under atmospheric conditions can be used.

Anions that bind with the cations can be all biocompatible ions. Typically chlorine (Cl) may be used, borate such as PO ₄ ^2- , HPO ₃ ⁻ , CO ₃ ^2- , HCO ₃ ⁻ , SO ₄ ^2- , B ₄ O ₇ ^2- , and many conventional anions Can be used. In addition, certain organic polyvalent anions may be used. For example, citrate, oxalate and acetate can be used. In certain instances, it is preferable to use hydrated ion complexes because certain hydrated ion salts dissolve more readily than dry salts.

In addition, the amount of hydrogen cross-linking is increased by decreasing the pH of the binding complex. Likewise, increasing the degree of substitution of carboxypolysaccharides in the gel can increase cross-linking in the binding complex at any given pH or ion concentration. The pH of the gel may be between about 2 and about 7.5, or between about 6 and about 7.5, and in another example, may be between about 3.5 and about 6.

E. Acid-side Methods of Degree of Ionic Bonding of Ionic Cross-Linking Gels

The degree of cross-linking and ionic bonding can be varied by varying the concentration of cations used. The method of comparing the change in the viscosity of the gel in the present invention is to compare the gel viscosity measured as a function of the acidity degree of the ionic bond. The degree of ionic bonding correlates with the degree of cross-linking between the polymer chains in the cross-linked gel. The method of measuring the ionic binding of the ionic cross-linked gel can be measured according to the following method illustrated for CMC. CMC consists of repeating units of carboxymethylated unhydroglucose units (herein referred to as "CMAG" units). 100% ionic bonding is achieved when 3 CMAG units associate with one trivalent ion, such as Fe ³⁺ . Theoretically,% ionic bond (% IA) correlates with the number of moles of trivalent ions ("I ³⁺ ") and the number of moles of CMAG ("CMAG") as

For example, the amount of iron chloride (FeCl ₃ ) is 30% ionic binding of a 500 mL sample of a gel containing 95% / 5% CMC / PEO using 2 wt / vol% total solids, 8,000 kd molecular weight PEO. It is necessary to generate CMC has a degree of substitution of 0.82. The amount of CMC is corrected for the moisture content (6% moisture) and degree of substitution present in the macromaterial. A degree of substitution of 0.82 was made such that the CMC had 8.2 carboxymethyl groups per 10 unhydroglycose units. Therefore, it can be expressed as follows.

Therefore, the number of moles of CMAG = 0.0303.

Representing Equation 1 above, solve for the number of moles of iron is as follows:

Thus, the required volume of 25.2 (weight / volume)% FeCl ₃ · 6H ₂ O solution is as follows:

Table 1 below shows a comparison of ion concentration and ionic binding acid percentage for each ion indicated for gels prepared with a CMC: PEO ratio of 95: 5 and a 2% total solids content.

For example, the viscosity of the gel can be increased by increasing the concentration of Fe ³⁺ . However, this effect has a maximum at a concentration of Fe ³⁺ sufficient to produce a gel having between about 35% and about 50% of theoretical maximum cross-linking, based on the availability of carboxyl groups (see Example 31). . By further increasing the cross-linking, the acidified viscosity can be reduced (see FIGS. 23 and 24 below). Likewise, in gels having a solid of 1.33%, a CMC: PEO ratio of 97: 3, and a PEO of molecular weight of 8 kd, Ca ²⁺ and Al ³⁺ have maximum concentration dependence. However, the maximum Ca ²⁺ has only a total theoretical cross-linking on the order of 5% and Al ³⁺ has a maximum at a theoretical maximum cross-linking on the order of 45% (FIG. 23).

As prepared using trivalent cations in a concentration range that provides maximum ionic bonding, gels having a high degree of solids or a high degree of cross-linking can be obtained at low ion concentrations and / or low valence ions. Can be dissolved more slowly than gels prepared with. These gels are characteristically slow to heal and unsuitable for use during regeneration from surgical treatment on ligaments, tendons, and tissues. Thus, the organ-retention composition can minimize the formation of adhesions between these tissues.

F. Properties of Ionic Cross-linked Polyacid Polyalkylene Oxide Compositions

1.Retention time, viscosity and composition of polyacid polyalkylene oxide composition

In the ionic cross-linking composition of the present invention effective to reduce adhesion, the material must remain in the site for a long time sufficient to allow tissue regeneration to occur while the tissue is separated. The tissues need not be completely healed to reduce the symptoms of adhesions, adhesions, but rather, it may be desirable to allow the composition to remain in view immediately after surgical treatment. The length of time a composition remains at a tissue site may vary depending on the performance of the composition that adheres to the tissue, the performance referred to as "bio-binding."

Biocompatibility is defined as the attachment of macromolecules to biological tissues. Biocompatibility is very important in preventing surgical adhesion because the temporary barrier layer should not slide out of the surgical site after it is in place. Both CMC and PEO are individually bioactive (see, eg, J. Pharm. Pharmacol. 43: 457-464 (1991) by Bottenberg et al.). Like other polymers known to swell upon exposure to water, CMC / PEO gels and membranes are also biocompatible.

Hydration reactions contribute to biocompatibility (Gurnety et al. Biomaterials 5: 336-340 (1984); Chen et al. Compositions Producing Adgesion Through Hydration, In: Adhesion in Biological Systems, RS Manly (Ed.) Acad. Press NY (1970) ), Chapter 10). A possible reason for this phenomenon is the increased hydration, which exposes more charges to polyacids, which may be used to bind tissue proteins. However, excessive hydration reactions inhibit biobinding. Thus, the means for controlling the biocompatibility of the gel composition and the membrane is to control its hydration properties.

Biocompatibility may vary depending on the viscosity and / or charge density of the gel. Possible mechanisms may be that positively charged sites introduced with polyatomic or polyvalent cations may interact with negatively charged sites on the tissue. However, other mechanisms may explain this phenomenon, and the present invention is not based on any particular theory or mechanism. Gels prepared according to the invention have surprising properties that are unpredictable in the prior art. Surprisingly, it has been found that the addition of polyvalent cations to a mixture of polyacids and polyalkylene oxides increases the viscosity beyond what is expected based on polyacids and polyalkylene oxides alone. In addition, it is surprisingly new that the addition of polyethers to a mixture of polyacids and polyvalent cations can increase the viscosity beyond what is expected based on the polyacids and ions alone. In addition, these results are surprising in that they are based on the absence of an increase in viscosity of the polyalkylene oxide solution by ion addition. Air conditioning between such polyacids / polyethers and polyvalent cations can provide a broader range of biophysical properties of the present compositions than previously available.

In addition to altering the valence and ion concentration of ions of the bond complex, increased binding between macromolecules can be achieved using polyacids with the number of acid groups augmented. By increasing the number or density of acidic groups, ionic bond formation, etc., is increased even at relatively low pH. The degree of substitution ("d.s") must be greater than zero, that is, some acid groups available for forming ionic bonds. However, the upper limit is theoretically 3 for cellulose derivatives with carboxylic acids, whereas for each mole of saccharides, there may be 3 moles of carboxyl groups. Thus, in the most common use of the present invention, d.s. is greater than 0 and up to 3 inclusive. Preferably, the d.s. is 0.3 to 2. CPS having a d.s. of 0.5 to 1.7 is effective, and CPSs having a d.s. of between about 0.65-1.45 are good to use and commercially available.

The viscosity of the gel can vary depending on the molecular weight of the PA. The higher the molecular weight, the more acidic groups are present per mole of PA, thus creating more opportunities for ionic interactions occurring between different molecules in solution. In addition, the increase in molecular weight creates longer PA chains and may provide more opportunities for bonding with nearby polymers. More of this can be combined to create an entangled polymer network. Thus, in one example where the polyacid is CPS, the molecular weight of the carboxypolysaccharide can vary from 10 kd to 10,000 kd. CPS in the range of 600 kd to 1000 kd is good, and 700 kd CPS is good, and commercially available products can be easily purchased.

2. Resorption of Ionic Cross-Linked Polyacid Polyalkylene Oxide Compositions

The gel composite of the present invention is intended to have a limited residence time in the body. Once placed on the surgical site, the composition is such that it can serve as a barrier for a defined period of time. Once substantially done, the anti-adhesive barrier naturally degrades, causing the components to disappear from the body.

The disintegration and dissolution rate and degradation of the composition can be increased by careful adjustment of the concentration in the formation of the ionic composition and the binding complex and by changing the PA / PO ratio and selecting the appropriate degree of substitution of the molecular weight of PA and PO and PA. Can be. Reducing the molecular weight of CPS increases its solubility (Kulicke et al. Polymer 37 (13): 2723-2731 (1996)). The strength of the gel or membrane can be adjusted according to the surgical use. For example, certain surgical uses (eg, spinal or tendon) may require materials that are stronger and more durable than others (such as intraperitoneal use). Manipulation of experimental variables as described above allows the manufacture and use of products with varying in vivo retention time.

3. Sterilization of Polyacid Polyalkyllan Oxide Compositions

After preparation, the gels and membranes of the present invention are packaged and sterilized using steam autoclaving, ethylene oxide, γ-radiation, electron beam light irradiation or other biocompatible methods. Autoclaving can be performed using any suitable temperature, pressure and time. For example, 20 minutes at a temperature of 250 ° F. is suitable for most productions. For manufacturing processes that should not be exposed to the water vapor of the autoclave, the composition, including the dry film and / or sponge, may be irradiated with gamma radiation. In certain examples, the intensity of light irradiation ranges from about 1 megarad (“MRad”) to about 10 MRads, or from about 2 MRads to about 7 MRads, in another example about 2.5 MRAds, or other examples. Is about 5 MRad. Gamma radiation can be performed using, for example, a device from SteriGenics, Corona, CA. Sterilization processes can alter the chemical and physical properties of the composition and its individual components, thereby increasing the bioresorbability of the composition.

III. Formulation of drugs in the composition

Ionic cross-linked gels and membranes can be prepared by combining the drug to be delivered to the surgical site. Formulation of drugs in membranes is described in US Pat. No. 4,713,243 to Schiraldi et al. This formulation can be added to the preparation step or afterwards prior to insertion. Drugs for preventing adhesion formation may include antithrombogen or tissue plasminogen activator such as heparin, and anti-inflammatory drugs include aspirin, ibuprofen, ketoprofen or other nonsteroidal anti-inflammatory agents. . Furthermore, hormones, cytokines, osteogenic factors, chemotactic factors, peptides and proteins with arginine-glycine-aspartate ("RGD") motives, analgesics or anesthetics are prepared or suitable for the composition. Can be added at the time of fire. All drugs or other agents suitable for the compositions and methods of preparation can be used in the present invention.

IV. Uses of PA / PO Compositions

The type of surgical treatment in which the membrane and / or gel compositions of the invention can be used is not limited. Examples of surgical procedures include open surgery, ophthalmic surgery, orthopedic surgery, gastrointestinal surgery, thoracic surgery, brain surgery, cardiovascular surgery, gynecology surgery, arthritis surgery, urology surgery, plastic surgery, musculoskeletal surgery, otolaryngology surgery, and spine Surgery is possible.

Adhesion formation occurs between 67% and 93% of all laparotomy and laparoscopy. Specific open procedures include intestinal, caecum, gallbladder resection, hernia repair, dissolution of abdominal adhesions, surgery of the kidneys, bladder, urethra, and prostate.

Gynecological treatment includes surgery to treat infertility due to bilateral fallopian disease caused by adhesions to the ovaries, fallopian tubes and fallopian tubes. Such surgeries include salingostomy, salpingolysis, and ovariolysis. In addition, gynecological surgery includes endometrial ablation surgery that prevents the creation of adhesions from the outset, treatment of ectopic pregnancy, myomectomy of the uterus or base, and hysterectomy.

Musculoskeletal surgery includes lumbar spine, sacrum, sternum and cervical hysterectomy, lumbar spine, sacrum, sternum and neck discectomy, flexor tendon surgery, spinal fusion and joint replacement or reconstruction, and other spine treatments.

Thoracic surgery, including laparotomy or thoracotomy, can be dangerous after primary surgery because adhesions are created between the heart or the aorta and the thorax. Thoracic surgery includes bypass surgery, and heart valve replacement surgery.

Since many brain surgery procedures require more than one treatment, adhesions, including skull, meninges, cerebral cortex, sinus cavities, and ears, can complicate secondary sagging.

Ophthalmic surgery applications include strabismus surgery, glaucoma removal surgery, and lacrimal drainage surgery.

In addition, the compositions of the present invention can be used to prevent recurrence of underlying adhesions and adhesions at localized sites and at some distance from the direct site during surgery.

In addition to surgical use, it is easy to reduce adhesions of the membrane and / or gel compositions of the present invention, promote healing following traumatic wounds or disease processes, thereby limiting the performance of the healed tissue appropriately. Can be used. Examples of injuries include cuts, cuts and abrasions. Examples of diseases include arthritis, boils and autoimmune diseases.

For example, the severity of arthritis disease and joint inflammation can be reduced by injecting the composition of the present invention. In addition, arthroscopic treatment may be advantageous by using the gel of the present invention. In arthroscopic examination, the doctor can see the inside of the joint through a small diameter endoscope inserted into the joint through a small incision. The joint may be operated through similar ablation using a fiber optic endoscope. In addition, examination arthroscopy can be used for the jaw joint, shoulder joint, elbow joint, lumbar joint, finger joint hip joint and ankle joint. Surgical arthroscopic treatments include joint synovial resection, cartilage repair, removal of loose body tissue, and removal of trace tissue or adhesions. In addition, the compositions may be injected directly into the joint for joint synovial complement. In addition, the compositions of the present invention can be used as tissue lubricants or used to lubricate surgical instruments before or during use.

Additional uses of the compositions of the present invention include use as a lubricant for ablation of a medical device such as a catheter, and for reducing the trauma caused by the medical device and device. By coating the surface of the device or device prior to use, the friction of the device against tissue can be reduced. By reducing trauma, medical devices can reduce the tendency to promote the formation of undesirable adhesions.

V. General Methods of Testing and Evaluating Anti-Adhesive Membranes

A. Membrane Hydration Rate

To measure the rate of hydration and the rate of hydration of the membrane, preferably, 160 mg of dried membrane pieces are placed alone in a glass vial and 20 ml of phosphate buffered saline solution (PBS, 10 mM, pH 7.4, Sigma Chemical Company, St. Louis, MO) Was added. The membrane was hydrated while producing a soft hydrogel sheet. After a period of time (typically 1 to 5 days), each hydrated membrane was carefully removed from the test vial and placed in a polystyrene petri dish. Excess water was removed using a disposable pipette and sucked out of the membrane using thin paper. Then weigh the cornea and use the formula The hydration rate (% H) was measured accordingly:

% H = (wet mass-dry mass) x 100%

Dry mass

B. Solubility of the Membrane

To determine the solubility of the membrane, the relative solubility in water and the aqueous stability of the membrane were measured as a function of its chemical composition. The solubility of the membrane in water is related to the membrane's resorption time in vivo.

Typically this test was performed with the hydration measurements summarized above. However, during the hydration test the membrane is exposed to salts because it is exposed to PBS. The salts thus added cause artificially high dry weights. Thus, after measuring the hydration rate, the membrane is immersed in deionized water (30 min at 30 ml) to remove salts incorporated in the polymer network. The water was decanted and fresh 30 ml of deionized water was added in portions. The membrane was immersed for another 30 minutes, taken out of Petri dishes, sucked to dry, and placed in a gravity transfer oven at 50 ° C. to dry.

The drying time depends on the amount of water the membrane absorbs. A highly hydrated, gel-like membrane was taken and dried for up to 24 hours, while the partially hydrated membrane was only dried for several hours. After excess water was removed from the membranes, they were allowed to equilibrate for 1-2 hours at room temperature before weighing them. The gravimetric measurement was repeated until a constant weight was obtained. Typically, during this period, some moisture is absorbed from the air, resulting in some rehydration of the membrane.

After desalination described above, the membrane was placed in a Petri dish containing 30 ml of deionized water and hydrated for a period of 20 minutes to 5 days. In preliminary studies, the membrane did not disintegrate during the 1 hour desalination process within and below the pH 6 range.

The solubility (S) of the membrane was calculated using the following equation:

% S = (dry weight before immersion-dry weight after immersion) x 100%

Dry weight before PBS dipping

The dry weight before immersion is the weight after desalination, and the dry weight after immersion is the weight after hydration in water.

C. Measurement of Acid Load Carried by Membrane

This test was performed in combination with the hydration and dissolution tests described above. This test represents an acid load that the membrane can carry to tissue when transplanted into an animal or human subject. After preparation, the membrane was placed in a PBS solution, causing a decrease in pH of the measurable PBS solution and releasing protons in the complex in a time-dependent manner.

Acid loading tests were performed using a model 40 pH meter (Beckman Instruments, Fuulerton, Calif.). 160 mg of dry film was placed in a glass vial and 20 ml of PBS was added. The initial pH of the PBS solution was 7.40; The pH of this solution gradually decreases because the polymer in the membrane partially dissolves and thereby reveals more quantized carboxyl residues. In highly hydrated membranes (pH 4-7), this process is accelerated because the polymer chains are broken by the hydrostatic forces generated during the hydration process.

In the following embodiments, gel compositions ionically cross-linked with carboxypolysaccharide / polyether membranes for CMC as illustrative carboxypolysaccharides are described. It is to be understood that other carboxypolysaccharides, other polyacids, polyethers and other polyalkylene oxide related complexes can be prepared and used in a similar manner. Thus, the present invention is not limited to these embodiments, and any homogeneous aspect may be performed without departing from the invention.

Example 1 CMC / PEO Neutral Film

Type 7HF PH (MW approximately 700 kd; lot FP 10 12404) was obtained from the Aqualon Division of Hercules (Walmington, DE). PEO with an MW of about 900 kd was obtained from Union Carbide (Polyox WSR-1105 NF, Lot D 061, Danbury CT); PEO with an MW of about 1000 kd was purchased from RITA Corporation (PEO-3, Lot 0360401, Woodstock, Illinois).

Membranes with a 65% CMC and 35% PEO composition were prepared as follows: 6.5 g of CMC and 3.5 g of PEO were dry mixed in a weighing dish. A model 850 experimental mixer (Arrow Engineering PA) was used to stir 500 ml of deionized water at a vortex of about 750 rpm. CMC and PEO were gradually dispersed in water stirred for 2 minutes. Since the viscosity of the polymer solution increases as the polymer is dissolved, the stirring rate gradually decreases. After about 15 minutes, the stirring rate was about 60-120 rpm and stirring was continued for about 5 hours to obtain a homogeneous solution containing a total polymer concentration (wt / wt) of 2% without visible aggregation.

Instead of pre-mixing CMC and PEO, an alternative method of formulating a mechanical casting solution is to dissolve the polymer separately. The anionic polymer, CMC, can then be oxidized by adding an appropriate amount of HCl. For example, by adding 2700 μl of concentrated HCl, 500 ml of 2% CMC prepared by dissolving 10.0 g of CMC 7HF in 500 ml of deionized water was oxidized to pH 2.6 (“Solution A”). Individually, a batch of 2% PEO was prepared (w / v 900,000 MW, "Solution B"). Then, the experimental stirrer of Example 1 was set at 60 rpm, and solutions A and B were thoroughly mixed at a specific ratio. Total polymer concentration was maintained at 2% (w / v) according to Examples 1-2.

20 g of solution was poured into 100 x 15 mm round polystyrene Petri dishes (Fisher Scientific, Santa Clara, Calif.) To cast the membrane from solution. Petri dishes were placed in a set of experimental gravity transfer ovens at 40-45 ° C. and dried overnight at about 760 Torr. The resulting film was carefully removed from the polystyrene surface using an Exacto knife.

For large membranes, 243 x 243 x 18 mm polystyrene dishes (Fisher Scientific) were used. Using the same weight in terms of surface area relative to the circular membrane (in this case 220 g of casting solution), a membrane having a dry weight of about 4.5 g was produced. This membrane looks homogeneous, smooth and flexible. Placing 160 mg of membrane in 20 ml of PBS solution (pH 7.4) does not change the pH of the solution. Drying tension and% elongation at crushing were somewhat higher than the corresponding membranes prepared from the oxidized casting solution (Table 2). When placed in deionized water or PBS, the membrane expands excessively and loses its sheet structure rapidly (within 10 minutes), forming a gel-like material that eventually disperses homogeneously in the polymer solution.

Example 2: Moderately Oxidized CMC / PEO Membranes and Hydrogels

The method for producing an oxide film in the intervening pH range (2.5 <pH <7) follows the method outlined in Example 1 initially. Stir the polymer solution at 60-120 rpm for 1 hour and oxidize the neutral mixed polymer solution comprising the polymer specified in Example 1 by addition of concentrated hydrochloric acid (HCl, 37.9%, Fisher Scientific, Santa Clara, Calif.) . Initially, a white precipitate is formed in the solution; The precipitate gradually disappears and a stable solution is formed. Typically, it has been found that 2% total polymer concentration is appropriate to achieve the desired viscosity in a stable casting solution. Higher polymer concentrations result in polymer solutions that are too viscous and difficult to follow. Lower polymer concentrations significantly increase the drying time for the same membrane and require more casting solution for the weight of the same membrane. In 500 ml of the 65% CMC / 35% PEO polymer mixture of Example 1, 1500 μl of concentrated HCl is required to obtain pH 3.1 in the casting solution. The viscosity of the starting polymer solution was dropped by 50% or more by the oxidation process.

Titration curves of various polymer mixtures (as well as 100% CMC and 100% PEO) are shown in FIG. 2. 2 shows the amount of HCl required for the preparation of a casting solution with the desired pH depending on the composition of the CMC / PEO mixture. Membranes made from 100% CMC (■) require more acid than other compositions to achieve the same degree of oxidation. Increasing the concentration of PEO (reducing the concentration of CMC) reduces the amount of acid needed to oxidize the casting solution to the desired degree. If the PEO concentration is increased to 20%, the effect is small despite the molecular weight of PEO being 200 kd (●) or 1000 kd ((). Increasing the PEO concentration from 40% (+) to 100% (□) further reduces the amount of acid needed to obtain the pH of the desired casting solution.

A. Viscosity of Hydrogel

Since the antiadhesion of the hydrogel depends on its viscosity, we measured the relationship between the casting solution pH and the viscosity of the hydrogel. The viscosity of the PCS / PE solution was measured at 22 ° C. using a Brookfield ™ viscometer. Pamphlet Cellulose Gum , Hercules, Inc., Wilmington, DE (1986), page 28 was used. In short, the test solution composition was selected and the number of spindles and the rotational speed of the spindles were chosen as mentioned in Table XI on page 29 of Cellulose Gum. Viscosity measurements were made within 2 hours of stirring the solution. The spindle was contacted with the solution, the spindle was circulated for 3 minutes, and the viscosity measurements were read directly with centipoise on a Brookfield Digital viscometer (Model DV-II). 65% CMC / 35% PEO solution prepared with 7HF PH CMC and 1000kd PEO was examined at pH 7.5. Another 65% CMC / 35% PEO solution was prepared at pH 3.1.

Table 2 shows the change in viscosity due to oxidation of the casting solution. Reducing the pH from 7.5 to 3.1 reduces the viscosity of the foundry solution by more than half. Gels with higher pH have greater anti-adhesion because the viscosity of the hydrogel is associated with the property of inhibiting adhesion, perhaps due to its ability to stay in one site for longer periods of time. In addition, it is also possible to characterize the casting solution not only by its pH but also by viscosity. Therefore, when the measurement of pH is not easy or reliable, it is preferable to measure the viscosity. To prepare the membrane, an oxidation casting solution containing a weakly H-linked intermolecular PEO-CMC complex was poured into the following polystyrene dish and dried in the same manner as in Example 1. Physical properties were measured after drying.

B. Physical Properties of CMC / PEO Membrane:

The membrane tension and elongation were measured using a piece of membrane shaped like a "dog bone" with a width of 12.7 mm on the narrow side. The membrane was then mounted on an Instron ™ tester equipped with a 1-ton load cell. The crosshead speed was 5.0 mm / min. The thickness, tension and elasticity (% elongation of the membrane at fracture) were measured. Report results for samples that failed in the desired test area. Samples deemed to have lacked or considered inadequate testing and discarded these test results.

The membranes all have a thickness of less than 0.1 mm. Table 3 shows that as the pH of the membrane decreases from neutral, the stretch (% extensibility) decreases in tension and fracture. Similarly, decreasing the PEO concentration reduces the tension and the elasticity of the membrane.

C. Hydration of CMC / PEO Membrane in PBS

In order to evaluate the bioadhesion of the membrane, the ratio and limit of hydration of the CMC / PEO membrane were measured according to the above-described method.

3 shows the time path for hydration of CMC / PEO membranes according to the present invention. Membranes prepared with 80% CMC / 20% PEO (m.w. 900 kd) were rapidly hydrated at pH 4.31 (•). After 2 hours in PBS, the rate of hydration ((wet wt.-dry wt.) / Dry wt,% expansion) increased by 6000% or more. After 5 hours in PBS, the hydration rate of this membrane was almost 8000%. This highly hydrated membrane loses its cohesiveness and substantially disintegrates accordingly. By lowering the pH of the membrane to 3.83 and below, the membrane is almost hydrated to its equilibrium point within 2 hours, and its degree of hydration and cohesion is maintained for at least 40 hours. The degree of hydration depends on the pH of the membrane with a minimum acidic membrane that can expand to a higher degree.

At pH 3.83 (▲) the membrane has a hydration rate of almost 6000%, while the hydration rate at pH 2.0 (□) is less than 300%. Within the pH range of 3.2 to 4.3, the degree of hydration is very sensitive to pH.

4 shows another study summarizing the effects of membrane composition and pH on hydration of CMC / PEO membranes. In PBS, hydration is measured at least 6 hours after which the degree of hydration has reached nearly equilibrium in each membrane (FIG. 3). In each composition conducted the study, increasing the pH of the membrane increased the hydration of the membrane. The hydration rate of the 100% CMC membrane (■) increased from about 100% of its hydration at pH 1.7 of the membrane to 1300% or more at pH 3.4. In membranes made with 80% CMC / 20% PEO, the molecular weight of PEO has a minor effect on hydration. Membranes made of 900 kd PEO (▲) hydrated slightly at a given pH than membranes made of 200 kd PEO ((). In addition, a high degree of substitution (ds = 1.2; The membrane consisting of CMC with) was hydrated similarly to 100% CMC (■) with about 0.84 substitution. Finally, membranes made with 50% CMC / 50% PEO (900 kd) were less hydrated than any other membrane except for low pH (<2.5) membranes.

D. Solubility of CMC / PEO Membrane

Since the biodegradation of the CPS / PE polymer was related to solubility, the solubility of the membrane was measured after at least 4 days in PBS according to the method described above. 5 shows the effect of the pH and composition of the membrane on the solubility of the membrane in PBS solution. The membranes were prepared at separate pHs with separate CMC / PEO compositions. In all membranes, solubility in PBS increased with increasing pH of the membrane. Membrane of 100% CMC (■) is least dissolved. Membranes comprising PEO dissolve better, and membranes made of 900 kd PEO (▲) dissolve less than those of 200 kd PEO ((). In addition, the solubility of the membrane further increased as the percentage of PEO increased to 50% (+). Reduction of CMC (7MF; *) molecular weight increases solubility. In addition, the degree of substitution of CMC ranges from 0.84 to 1.12 ( Increasing) results in a better soluble film. Also, as the degree of substitution became higher, the influence of pH on the solubility of the membrane became larger. In other membranes, the effect of increasing pH, despite the composition of the membrane, appears to exhibit the same effect. Thus, the slope of the straight line is similar. These results indicate that, regardless of the composition of the membrane, the solubility of the membrane increases with increasing pH of the membrane. In addition, because bioresorption requires dissolution, higher soluble membranes will be processed faster in the body than less soluble membranes.

E. Bioavailability of CMC / PEO Membrane

Because bioavailability is associated with acid load to the tissue, the acid load carried in the PBS solution by the CMC / PEO membrane was measured as described above in an appropriate in vitro model. First, the time course for the oxidation of the PBS solution exposed to the separate composition of the CMC / PEO membrane was measured.

Table 4 shows the oxidation kinetics of PBS solution by the CMC / PEO membrane of the present invention. When added to the PBS solution, the membrane releases the acid into the solution, thereby lowering the pH of the solution. This process takes place slowly for the membrane containing the high molecular weight PEO, reducing the pH of the solution to about 1 pH unit for the first hour. This applies not only to castings obtained from high pH polymer solutions, but also to membrane castings obtained from low pH polymer solutions. The remaining decrease in pH occurs over the next 20 hours, at which point the solution's pH remains nearly constant. By 45 hours in PBS solution, the pH decreased below 6.0.

In addition, as the molecular weight of PEO decreased, the pH of the solution decreased faster and to a higher extent than membranes made of higher molecular weight PEO. This is due to the ability of PEO with high molecular weight to protect the acidic carboxyl residue of CMC and thereby reduce dissociation of carboxyl hydrogen ions.

These results suggest that high molecular weight PEO acts to slow the transport of acids into tissues and thus protect them from excessive oxidation. In addition, because protons are released in vivo, they will be diluted in extracellular space, buffered by physiological buffers, and ultimately removed from tissue by the lymphatic and circulatory systems. During the relatively long time that the protons are released, physiological dilution, buffering and removal mechanisms will remove the acid load while maintaining pH within the tissue within acceptable ranges. Thus, these membranes are suitable for in vivo transplantation without causing excessive tissue disruption due to the large amount of acid load carried.

Figure 6 shows the results of the study of the pH of the PBS solution varies depending on the pH and membrane composition of the membrane. The membrane is left in PBS solution for 4-5 days, which is the time for the oxidation to reach equilibrium (Table 4). The composition of the film causing minimal oxidation is a pre-set 80/20 / 300k film (o). These membranes were prepared according to the above technique except for the additional step of dipping the membranes in PBS and then re-drying (Examples 7-9). The 80/20 / 300k membrane castings (+) in PBS carry the next lowest acid load, and the membranes of the 50/50 CMC / PEO (900k) series carry the third lowest acid load in the PBS solution. Membranes (■), 80/20 / 200k (●) and 80/20 / 900k (▲) made with 100% CMC gradually carry more acid to PBS and were made with CMC with a degree of substitution of 1.12. The 80/20 / 300k series membranes carried the most acid in the PBS solution.

FIG. 6 also indicates that the setting membrane dipped in PBS reduces the load of acid carried in the PBS solution. For example, pre-set membrane castings at the original pH 3.4 reduced the pH of the PBS solution from only 7.4 to 7.0. Thus, in such applications where long term permanent membranes are required, but which cause minimal oxidation, pre-setting of the acidic membranes in PBS is preferred.

Example 3: Membranes with Individual PEO / CMC Ratios

500 ml batches of 80/20 CMC / PEO membranes were obtained by dissolving 8.0 g CMC and 2.0 g PEO in 500 ml of deionized water (source of CMC and PEO, and dissolution process as in Example 1). Stirring at low speed (60 rpm), using a 1500 μl of 5N HCl (LabChem, Pittsburgh, Pa.) At a pH equilibrium of 3.17, 200 g of the polymer solution was oxidized. The oxidized polymer solution was then poured into a polystyrene dish and dried in a similar manner to Example 1. By varying the relative amounts of CMC and PEO, membranes with separate compositions were obtained. 100% CMC membranes are brittle and less flexible than PEO-containing membranes. For this purpose, membranes containing 70% or more of PEO are generally undesirable because they are unstable in an aqueous environment.

Table 5 shows the effect of the CMC / PEO ratio on the viscosity of the solution. Membranes were prepared by varying the percentage of PEO at two different pH (m.w.:1,000,000). Solutions containing higher proportions of CMC are more viscous than solutions containing less CMC. In addition, less acidic solutions have a higher viscosity compared to more acidic solutions. This relationship applies to all solutions except 100% CMC solution. The viscosity at pH 2.6 is slightly higher than pH 4.0. This is probably due to CMC intermolecular relationships at lower pH.

The mixing of the two solutions resulted in a greater decrease in viscosity than expected. For example, a 85% viscosity decrease was obtained when Solution A (pH 2.6) and B were mixed at a 50/50 ratio. At spindle rpm 2.5, a solution with a 2% CMC starting concentration (w / v) of pH 2.6 had a viscosity of 42,400 cps and a 2% PEO solution had a viscosity of 280 cps. Thus, if the viscosity of the mixture is an average of the viscosity of its components, it would be expected that the 50/50 CMC / PEO solution would have a viscosity of (42400 + 280) / 2 = 21300 cps (a 50% viscosity decrease over about CMC alone). However, substantially CMC / PEO (50/50) solutions have a viscosity of only 4,800 cps. Similarly, in PEO mixed with dextran and inulin, more than expected viscosity decreases have been reported in Ohno et al. ( Makromol. Chem. Rapid Commun . 2, 511-515, 1981).

Further demonstration of the molecular intercomplex between CMC and PEO is shown by comparing the relative viscosity decrease caused by oxidation of 100% CMC and CMC / PEO mixtures. Table 5 shows that at 2.5 rpm, the viscosity of the CMC solution remains substantially unchanged when the pH decreases from 4.0 to 2.6. However, in the mixture of CMC / PEO, the oxidation caused a significant decrease in viscosity. This reduction was 69%, 63%, 53% and 42% in the CMC / PEO 66% / 33%, 50% / 50%, 33% / 66% and 25% / 75% mixtures, respectively.

Thus, we theorized the presence of molecular interrelationships between CMCs / PEOs, resulting in PEO molecules interspersed between CMC molecules and thereby inhibiting CMC intermolecular bonds. While this theory may explain the observations, it is not intended to limit the invention to any single theory between molecules. Other theories can explain the observations.

Next, after preparation of the membranes with distinct CMC / PEO ratios, the hydration, acid loading and solubility were studied using the method described above.

Table 6 shows the effect of increasing the PEO concentration in CMC-PEO on% water uptake, oxidation and mass loss. Increasing the PEO content in the membrane increases the hydration rate and solubility and reduces the acid load carried to PBS. These results indicate that the acid load decreases because the total amount of CMC in the membrane decreases.

The effect of separate CMC / PEO ratios is further demonstrated in FIG. 5 (soluble vs. membrane) and FIG. 6 (oxidative vs. PBS solution of membrane).

Example 4: Membrane of PEO with Separate Molecular Weight

Separate molecular weight by mixing 2% (w / v) PEO solution with 2% (w / v) CMC solution (type 7HF PH (lot FP 10 12404) purchased from Aqualon Division of Hercules (Wilmington, DE) A membrane of PEO was prepared A PEO having a molecular weight of 8000 (8K) was obtained as polyglycol E8000NF from Dow Chemical, Midlands, Michigan From Union Carbide having a molecular weight of 300,000 (300K), 900,000 (900K) and 5,000,000 (5M) All PEOs were purchased A 2% (w / v) PEO solution was prepared by dissolving 6.0 g of PEO in 300 ml of deionized water according to the method of Example 1. Dissolving 10.0 g of CMC in 500 ml of deionized water A CMC shock solution was similarly prepared by oxidizing the CMC shock solution by adding 2100 μl of concentrated HCl to reduce the pH of the casting solution to 3.37.

A 50% CMC / 50% PEO (SK) membrane was prepared by mixing 40.07 g of CMC stock solution and 40.06 g of PEO (SK) stock solution. The casting solution was oxidized to pH 3.46. A 50% CMC / 50% PEO (300K) membrane was prepared by mixing 39.99 g of CMC stock solution and 40.31 g of PEO (300K) stock solution and the pH was lowered to 3.45 by adding sufficient HCl. 39.22 g of CMC stock solution and 39.63 g of PEO (900K) stock solution were mixed to prepare a 50% CMC / 50% PEO (900K) membrane and the pH was lowered to 3.56 by adding sufficient HCl. A 50% CMC / 50% PEO (5M) membrane was prepared by mixing 38.61 g of CMC stock solution with 40.00 g of PEO (5M) stock solution and the pH was lowered to 3.55 by adding sufficient HCl. Membranes prepared from these variously oxidized CMC / PEO mixtures were cast and dried according to the method of Example 1. 7 shows the effect of PEO weight on the hydration rate of the resulting membrane. This result indicates that hydration hardly increased when the molecular weight of PEO increased from 900 kd to 5000 kd, but the hydration rate increased as the molecular weight of PEO increased. In addition, it is possible to observe the difference between the membranes prepared in PEO having various molecular weights from the numerical values shown in FIGS. 4-6.

Example 5: Membrane of CMC with Separate Molecular Weight

50% CMC / 50% PEO membranes were prepared from CMC (type 7MF PH; Lot FP 10 12939, Aqualon Division of Hercules, Wilmington, DE) and Union Carbide (PEO) having a molecular weight of 900,000. In contrast to type 7HF CMC of "high viscosity", 7MF CMC has a very low viscosity in solution. The average molecular weight of type 7MF is about 250 kd, compared to 700 kd for 7HF type CMC. 5.0 g of CMC and 5.0 g of PEO (900 K) were pre-dried mixed and then dissolved in 500 ml of deionized water according to the method of Example 1. The pH was lowered to 3.48 by oxidizing the solution with 950 μl of concentrated HCl. Membranes were prepared from 20.0 g stock casting solution. The other part of the stock solution was used to make a more acidic membrane (using a casting solution with a pH of 3.07, 2.51 and 1.96). The membrane was cast and dried from this oxidation solution. After drying, the hydration, mass loss and acid load were measured as described above. In these membranes having pHs of 3.48, 3.07 and 2.51, the% mass loss and the hydration rate cannot be measured because the membrane is dissolved. The final pH of the PBS solution in each membrane was 5.93, 5.33 and 5.20, respectively. The membrane prepared at pH 1.96 retained its cohesiveness, the% mass loss was 60%, the hydration rate was 343%, and the pH of the PBS solution was 4.33. Compared with the low pH membrane and others (FIG. 5), the membrane made with lower molecular weight CMC was the most stable. Thus, the strength of the associated complexes depends on the molecular weight of the CMC.

Example 6: CMC / PEO Membrane with Different Degrees of CMC Substitution

CMC / PEO membranes were prepared from CMC (lot FP10 12159, degree of substitution (d.s.) 1.17, Aqualon Division of Hercules, Wilmington, DE) of type 99-12M31XP and Union Carbide (PEO) having a molecular weight of 300,000. 200 ml of mixed polymer solution was oxidized using 600 μl of concentrated HCl to obtain a stock solution of pH 4.07. 20.7 g of casting solution was poured into Petri dish; The membrane was dried as described in Example 1. The excess of stock solution was used to make membranes with increased acidity. The pH of the casting solutions for these membranes was 3.31, 3.03, 2.73, 2.44 and 2.17, respectively.

4-6 show the properties of these membranes in comparison to the others in the composition of CMC and PEO. 4 shows 1.12 ( It is pointed out that the hydration rate of CMC with degree of substitution is similar to that of other CMC / PEO membranes with a hydration rate of 836% placed in PBS for 4 days. However, there are differences in the characteristics other than measured. 5 shows that membranes made of CMC with higher degrees of substitution produce the most soluble membranes compared to other membranes. 6 shows that membranes made with highly substituted CMCs produce membranes that deliver the most acid load to PBS. This is consistent with the view that more hydrogen ions are useful for dissociation of these membranes made at higher ds at any given pH.

Example 7: Ammonia Control of Membrane

To study the effect of alkali control on CMC / PEO membranes, three pieces of dried membrane (about 160 mg, composition: 80% CMC (7HF PH) / 20% PEO (300K or 5000kd)) were placed in Petri dishes. Subsequently, 30 ml of 0.5 N ammonium hydroxide (10 × dilution of 5 N ammonia, LabChem, Pittsburgh, PA) was added. The membrane was completely submerged and allowed to soak in the membrane for 1 or 5 minutes. The membrane was removed from the membrane, the excess ammonia was sucked into the filter paper and the membrane was placed in a gravity transfer oven and dried at 45 ° C. After drying and re-equilibration at room temperature, the mass of the membrane was measured. And solubility was measured The results are shown in Table 7.

Table 7 shows that ammonia treatment substantially reduces the acid load carried into the PBS solution. In the magnified interpretation, this effect will also reduce the acid load carried to the tissue in vivo. In addition, when compared to other membranes carrying the same acid load in a solution other than PBS, the ammonia-regulated membranes have lower solubility, thus increasing the residence time in vivo. Thus, it is possible to introduce an antiadhesive membrane of long residence time that carries little residual acid into the tissue. In contrast, at pH about 7.0, the unregulated membrane disintegrates rapidly, and thus has little effect on inhibiting adhesion after surgery.

Treating the membrane after initial preparation reduced the acid load on the membrane. In all cases of modulated treatment the pH increased from about 4 to above the neutral pH level compared to the control (not immersed in ammonia). Compared to the control group, the control treatment also increased the hydration rate of the membrane. The increase in hydration was relatively smaller than the two types of acidic membranes, while the minimum acidic membranes (pH 3.1 80% CMC / 20% PEO (5M)) expanded to higher levels. Therefore, the effect of this treatment depends on the state of the film to be preferred. In both cases (80% CMC / 20% PEO (300 kd) pH 2.03 membranes), the total mass loss due to ammonia control is slightly lower than the control. This unexpected result is due to the initial loss of salt in ammonia solution followed by absorption of the salt by the salt-depleted membrane during immersion in PBS.

Example 8: Membrane Control with Phosphate Buffer

Similar to Example 7, the state of the membrane was adjusted after preparation in phosphate buffer (50 mM, pH 7.40). A piece of dry film was obtained (0.163 g; 80% dried at 45 ° C.). Upon re-equilibration at room temperature after drying, the mass of the membrane was 1.42 g (ie 13% mass loss). Prior to drying, the other membranes were soaked in buffer for 20 or 60 minutes. After drying, the membrane was inspected in the same manner as above. Hydration, acid load and solubility (after 4 days in PBS) for each membrane were measured and the results are shown in Table 8.

Table 8 shows that phosphate buffer control neutralizes the acid load carried in the PBS solution, such as ammonia control. In addition, increasing the duration of exposure to phosphate buffer caused gradual neutralization of the intramembrane acid. After 1 hour of incubation, the pH increased from about 4.3 to 7.30. These membranes remained intact in PBS for at least 3 days. In contrast, membranes prepared at the original pH of 7.0 were rather rapidly hydrated and completely separated and lost their prototype within a few hours. Thus, acidic membranes adjusted with alkaline or neutral phosphate buffers can reduce the solubility of the membranes (increase residence time in vivo) while maintaining high bioavailability pH. In addition, acidic membranes immersed in other neutral or alkaline buffer (eg pH 9.0 boric acid-KCl, NaOH, 0.1M; Fischer Scientific) solutions are also effective in reducing the acidity of the original membrane.

Example 9: Control Membrane Using PBS

To determine if an isotonic, phosphate buffered saline solution can reduce the acid load carried by the membrane, it was described in Example 8 using PBS (10 mM, pH 7.4, 3 washes, 20 minutes each) as buffer. One such experiment was repeated. Fragment of dried Petri dish containing 50 ml phosphate buffered saline (PBS) solution (10 mM, pH 7.40, Sigma Chemical Company, St. Louis, MO) (wt. 0.340 g; Composition: 80% CMC (7HF PH) / 20% PEO (300 kd); pH 3.1) and soaked for 20 minutes. The immersion process was repeated twice again by decanting the solution from the membrane and adding fresh PBS. Next, the membrane was removed from the PBS solution, allowed to soak and dried as above. After drying and re-equilibration at room temperature, the mass of the membrane was 0.274 g (19.4% mass loss). After drying, the hydration rate, acid load and solubility were measured as described above. The results are shown in Table 9.

Controlling the acidic membrane with PBS using phosphate buffers increases the pH of the membrane without completely disrupting the strong bonds between polymers originally present at lower pH. Thus, when the condition is adjusted using the PBS buffer method and subsequently placed in PBS, the pH of the original membrane results in a pH of 6.02. Non-regulating membranes which produce the same pH in PBS will inherently have a pH in the range of 3-4. In addition, except for pH lower than 2, the control membrane will hydrate to a higher degree than the non-control membrane. Thus, the modulating membrane retains some of the properties of the acidic membrane inherently, but further increases bioavailability by reducing the acid load carried in the solution.

Example 10 Multilayer CMC / PEO Membrane

In order to produce a more diverse film, an oxidized film was sandwiched between two layers of the neutral film, where the neutral film may or may not have the same CMC / PEO ratio as the oxidized film. The partially dried neutral film sheet was first placed on a flat dry surface used as the dry surface of the thin film. A sheet of partially dried oxide film with slightly smaller dimensions was carefully placed on the neutral film. Then, a sheet of another partially dried film was carefully placed so as to cover the top of the oxide film so that the edges of the two neutral films were aligned so that the oxidized film did not cross the edges of the two neutral films. All three sheets were properly placed and deionized water was slowly poured into Petri dishes, taking care not to get the sheets out of alignment with each other. Once all sheets are wet, the non-absorbent porous thin film, such as nylon filtration media, is carefully placed on a wet thin plate and only pressed lightly over it. This assembly was then left to dry, at which point the porous membrane was carefully removed and then the thin membrane removed from the flat surface.

In a similar manner, selective, bi-layer membranes were prepared. The two-layer film showed different characteristics in each side. A surface with less bioadhesiveness and a lower pH allows this side to slide more easily over tissue than a surface with a higher pH. Cotton with a higher pH will be in contact with the tissues and adhere more strongly and conform to gaps while better retained in place within the tissue. Such membranes are useful in that mobile tissues are generally free to move relative to more fixed tissues.

A partially dried membrane (ratio of CMC: PEO = 95: 5, pH 3.0, cast as 15 mg of 2% polymer solution) was placed on a Petri dish and a mixture of CMC / PEO (ratio of CMC: PEO = 95 :) on top of the membrane. Another two-layer membrane was prepared by pouring 5, pH 5.5, cast as 10 mg of a 2% polymer solution. The mixture and the partially dried film were dried together to form the final film of the two-layer. In a similar manner, bilayer membranes of various PEO compositions, such as two layers, with different PEO contents were prepared. The high PEO content of the film makes the surface of the film more slippery. Another membrane with a lower PEO content adheres more strongly to the tissue.

In abdominal surgery, the intestinal membranes move freely with respect to each other and the surrounding peritoneum. A further embodiment is thoracic surgery, in which the lungs must be able to move relative to the surrounding peritoneum. Positioning the side of the membrane with high pH towards the peritoneal wall will keep it in place but allow the visceral peritoneum attached to the lungs to move freely. Similarly, in cardiac surgery, placing the high pH side of the bilayer membrane on the peritoneum anchors the membrane in place, while the low pH side allows the cardiac tissue to slide more freely, such as the myocardium. Similarly, in orthopedic surgery, placing a high pH side of the membrane against an anchored tissue, such as bone or periosteum, allows the membrane to adhere more firmly to this position and less anchored tissue such as ligaments, tendons or muscles to move more freely. do.

Example 11: Effect of CMC / PEO Concentration on the Stability of Casting Solutions

To determine the effect of CMC and PEO concentration on the stability of the casting solution, 16 g of CMC d.s. = 1.2 and 4 g of PEO (300 kd) were added to 50 ml of isopropanol to prepare a slurry, again 450 ml of water. This is relatively homogeneous, but results in a more viscous casting solution compared to Examples 1-9. A series of membranes were prepared while oxidizing portions of the casting solution to lower pH gradually. Portions of 11 g of casting solution were poured into 10 cm Petri dishes and dried.

The membrane was homogeneous above a pH of about 3.3, while the binding complex precipitated out of the casting solution at lower pH. Membranes produced at lower pH contain inhomogeneous areas and pores and have rough surfaces.

The membrane can be prepared from a solution consisting of as much as 10 wt% CMC and as much as 20 wt% PEO.

Example 12 Antithrombotic Effect of CMC / PEO Membrane I

Samples of CMC (7HF PH) and CMC / PEO (5000kd) membranes with CMC / PEO ratios 80% / 20%, 65% / 35% and 50% / 50% at pH 2.7-2.9 were prepared. Observation chambers of sticky platelets were constructed comprising a polymer-coated glass slide, two polyethylene spacers, and a glass coverslip. After consent, blood from healthy adult volunteers was collected in heparin-containing collection containers (Vacutainers ™, Becton-Dickinson, Rutherford, NJ). Heparinized blood was centrifuged at 100 g for 10 minutes to obtain platelet-rich plasma (PRP).

200 μl of PRP was placed in platelet observation chamber. Platelets in RPR adhere and activate to the polymer surface for 1 hour at room temperature. The chamber was washed with PBS to remove non-attached platelets and plasma proteins. Adherent platelets were fixed for 1 hour with 2.0% (w / v) glutaraldehyde solution in PBS. After blotting with PBS, platelets were stained for 1.5 hours using 0.1% Coomassie Brilliant Blue (Bio-Red, Hercules, CA) staining solution. Stained platelets were observed using a Nikon Labophot ™ II light microscope at 40 × magnification (Melville NY). The appearance of adherent platelets was transferred to a Sony Trinitron ™ video display using a Mamamatsu CCD ™ camera (Hamamatsu-City, Japan). The Hamamatsu Argus-10 ™ image processing apparatus was used to calculate the number of platelets per 25,000 μm ² surface area over all observation ranges. The extent of platelet activity was measured qualitatively from the developing action of adherent platelets. Images of activated platelets were observed from Sony Trinitron ™ video display screens using a Polaroid ScreenShooter ™ camera (Cambridge, Mass.).

As an early indicator of the thrombosis of blood-containing biomaterials, the number of adherent platelets and the range of platelet activity are considered. Platelet activity was qualitatively determined by the range of platelet development on the polymer surface. Platelet translocation ranges from 1 (minimum reactivity) to 5 (maximum reactivity) as described in Table 10, based on Lin et al., Polyethylene surface sulfonation. Surface properties and platelet adhesion are described in J. Coll . Interface Sci . 164: 99-106 (1994), which is hereby incorporated by reference in its entirety.

Table 11 shows that a significant number of platelets stick and activate on the membrane consisting of 100% CMC. On average, there were more than 95 activated platelets per 25,000 μm ² . The number and extent of activation of adherent platelets decreased with increasing PEO content in the membrane. The number of platelets is minimal on CMC / PEO 50% / 50% membrane days. On average, only 5.0 contact-adherent platelets were present in these membranes.

The results of this study show that CMC / PEO membranes, especially 50% / 50% CMC / PEO membranes, are very thrombogen resistant, based on the reduced number of adherent platelets and the degree of platelet activation on these surfaces. Thus, increasing the amount of PEO in the membrane increases their anti-thrombogen properties.

To determine whether CMC and PEO adversely affect blood coagulation in vivo , a series of studies were conducted in which rabbits were infused with a CMC / PEO mixture and measured prothrombin time.

Four rabbits (2.4-2.8 kg) were added to ketamine (40 mg / kg) and xylazine. Anesthetize using (8 mg / kg) and use a 27-gauge, 1/2 inch needle with clinical grade 2% CMC, 0.05% PEO, 50% H2O and 47.9% balanced salt solution (Lot # SD011089). To the lower spine. Fifth, uninjected rabbit (2.8 kg) was used as a control. Blood samples (approximately 1.6 ml) were taken at 0 (prior to infusion), 2, 6, 24, 48, and 96 hours after dosing. To 1.6 ml of collected blood, 0.2 ml of 3.8% sodium citrate solution was added. After mixing the samples were prepared by centrifuging the sample for 3-5 minutes at 2000 rpm in a clinical centrifuge. The plasma was pipetted into separate labeled tubes and placed on ice. The samples were frozen and sent to Califonia Veterinary Diagnostics, Inc., West Sacramento, CA for determination of prothrombin time and treated according to the Good Laboratory Practice Regulation of FDA.

Table 12 shows the prothrombin time of each rabbit plasma sample at various sampling times. Rabbit blood coagulates faster than human blood (Didisheim et al., J. Lab. Clin. Med. 53 , 866-1959); Therefore, some samples taken from these rabbits were coagulated before analysis. However, the analyzed samples showed that the CMC / PEO mixture did not affect prothrombin time except for rabbit 3, which showed a temporary increase but recovered by day 4.

Example 13: Determination of Bioadhesiveness of CMC / PEO Membrane

The biotackiness of the membrane is generally measured using the peel test described below. Several membranes consisting of CMC (7HF PH) and PEO (molecular weight 5000 kd) and having varying acidity were tested using in vivo tests for their bioadhesive measurements. Fresh, centrally cut pork pieces purchased from a local store were used as the membrane coalescing material. Six sliced pork pieces were placed in a polystyrene bioassay dish (243 × 243 × 18 mm) and some water was added to the dish for a relatively humid environment. Excess water was sucked away from the exposed side of pork. The six membranes were cut into rectangular shapes of 120-130 mg in mass and placed on each of six pieces of pork with the soft side down. The soft side of the membrane is the side that adheres to the polystyrene surface during the drying process. The other side of the membrane exposed in air typically has a slightly rough surface. The top cover of polystyrene is placed on a dish and the membrane is hydrated and coalesced with pork for 3 hours at room temperature. In a similar manner, different membranes were tested using different bioassay dishes.

After a three-hour incubation period, membranes and pork were subjected to rippling, blanching, membrane type (folding on pork) as a result of strong bioadhesion, structural properties of the membrane, transparency (color, Transparency) and carefully tested in a qualitative manner for the measurement. The adhesive force (gm) is first peeled by sticking the clip to the membrane edge, then sticking the clip to the spring scale (range from 0 to 10 gm or 0 to 250 gm) and removing the membrane from the pork by setting the scale vertically. Qualitatively measured by test. The adhesion force (gm) required to completely detach the membrane from pork or, in some cases, to induce a rip to the membrane, was recorded.

The results shown in Table 13 show that the adhesion between CMC / PEO membranes is related to the pH of the membranes. At a given PEO ratio, the pH exhibiting maximum adhesion is about 3.30, but above or below this level the adhesion decreases. In addition, adhesion was related to the% PEO of the membrane. The membrane with the highest PEO ratio showed minimal adhesion. Increasing the ratio of PEO up to 5% PEO increased the adhesion, while increasing the ratio of PEO further decreased the adhesion.

Example 14 Removal of CMC / PEO in vivo

To determine the removal of CMC / PEO in vivo , a series of experiments were performed in which rats were injected with radiolabeled CMC and PEO (2% CMC, 0.05% PEO, 50% H ₂ O and 47.9 balanced salt solution). It was. The study was performed under Good Laboratory Practices.

Formulations comprising [ ¹⁴ C] carboxymethyl cellulose (CMC) and [ ¹⁴ C] polyethylene oxide (PEO) were injected into the lower spinal portion of 4 groups of 6 rats (3 males, 3 females); Two groups died after three days and the other two died after seven days. Urine and feces were collected daily from these rats to study radioactive excretion patterns. Two separate sets of 6 rats were similarly injected and the samples were examined for radioactivity at 0-time (before injection) and 8, 24, 48, 72, 96, and 168 hours after injection.

Initially both compounds were excreted in the urine. Most feces in the urine occurred during the first 24 hours. After 7 days of study, the half time of excretion of ¹⁴ C-CMC in urine and feces was initially about 0.2 days (5 hours) and then a longer excretion half time of about 1.6 days. Corresponding values of ¹⁴ C-PEO were 0.2 days (5 hours) and 1.7 days, respectively. In organ examination, liver and kidney showed the highest level of radioactivity. The ratio of dose injected into the liver was similar for ¹⁴ C-CMC and ¹⁴ C-PEO, but the ratio of dose injected into the kidneys was at least six times higher after ¹⁴ C-PEO injection than after ¹⁴ C-CMC injection. .

The radioactivity in the blood after ¹⁴ C-CMC injection decreased to about 1 day half life, whereas the blood half life after ¹⁴ C-PEO injection was about 4 days. The ratio of dose remaining at the body plus injection site was higher for ¹⁴ C-CMC than for ¹⁴ C-PEO. Overall recovery of dose was 80 +% for both compounds. ^No reaction to ¹⁴ C-CMC or ¹⁴ C-PEO was observed.

Example 15 Viscosity of CMC / PEO According to pH Action

For the determination of solution pH change for CMC / PEO solution, solution containing 1.33%, CMC: PEO ratio of 77.7: 22.5 and PEO molecular weight of 4.4 Md; ◆), CMC: PEO ratio of 50:50 and PEO The exact viscosity samples of the solution having a molecular weight of 4.4 Md;) and the solution having a CMC: PEO ratio of 50:50 and a molecular weight of 500 kd of 50% PEO; ▲) were measured (see FIGS. 8A-8B). Viscosity data were centipoise using spindle No. 4 at 0.5 rpm; It is represented by csp.

8A shows that at each pH, the viscosity of the solution with a CMC: PEO ratio of 77.5: 22.5 is higher than the viscosity of a solution with a CMC: PEO ratio of 50:50. In addition, for both solutions, an increase in pH increased the viscosity of the solution and showed a more pronounced change in viscosity when the pH value was above about 2. 8B shows similar results using a solution with a CMC: PEO ratio of 50:50 and a PEO molecular weight of 300 kd. In this solution, an increase in pH above about 3.0 results in a significant increase in viscosity.

Example 16: Determination of Turbidity in CMC / PEO Solutions

To determine if CMC and PEO were bound into large aggregates causing light scattering, the appearance of CMC / PEO particles in solution was measured using a nephelometry apparatus. Two kinds of turbidimeters were used; Model 21 turbidimeter (side scatter design, Monitek, Inc.) and model 251 (front scatter design, Monitek, Inc.). Absorbance was measured using a Monitech absorber with a tungsten lamp that provides visible and near infrared light emission.

After preparation of the study mixture, the mixture was kept homogeneous by stirring using a slow (60-120 rpm) experimental stirring device if necessary. The results of the study are shown in FIGS. 9 and 10. 9A shows the results of experiments measuring the effect of solution pH on the side scattering of a solution containing 1.33% total solids, 50:50 CMC: PEO ratio, and 4.4 Md PEO molecular weight, measured in turbidimeter units (NTU). . Above about pH 3, scattering was minimal and all data were below 10 NTU. As the pH decreased to 2.5, the side scatter slightly increased, and when the pH further decreased below 2, the side scatter increased significantly. FIG. 9B is an experiment similar to that shown in FIG. 9A, except that the solution has a CMC: PEO ratio of 50:50 and the PEO molecular weight is 500 kd. When the PEO molecular weight was higher, lateral scattering hardly occurred in the pH range of about 2.5 or more, but lateral scattering increased significantly in the pH range of about 2.5 or less.

FIG. 10 shows a similar study of a solution with a total solids content of 1.33%, a CMC: PEO ratio of 50:50 and a PEO molecular weight of 4.4 Md, with full spectral absorbance (right hand scale) expressed in absorption units (AU). Front scan scan turbidity, expressed in Δ) and NTU (left hand scale; DELTA). In the turbidimeter data shown in FIGS. 9A and 9B, in the pH range of about 2.5 or more, little turbidity or absorbance was observed, while in the pH range below about 2.5, turbidity and absorbance increased markedly with decreasing pH.

This study shows that at pH above about 2.5, CMC and PEO remain in suspension. However, when the pH decreases below 2.5, precipitation begins to form and form aggregates that scatter light so that the CMC and PEO are measurable (see FIGS. 9 and 10).

Example 17 Hydration of CMC / PEO Membrane According to pH Action

Three series of CMC / PEO membranes were prepared and studied, and the results are shown in FIGS. 11A and 11B. The first series consisted of 77.5% CMC / 22.5% PEO (4.4 Md;). The second series consisted of 50% CMC / 50% PEO (4.4 Md;) and the third consisted of 50% CMC / 50% PEO (300 kd; ▲). In each case, the membrane was dried and then immersed in PBS for 20 hours. After 20 hours, the membrane was blotted dried and the wet weight was measured. The hydration rate (% hydration) is expressed as (wet weight-dry weight) / dry weight x 100%.

11A shows the results of the experiment over the entire pH range studied. When the pH is about 2.0 and lower, the hydration rate hardly depends on the pH. However, as the pH increased above about 2.0, the hydration rate of each type of membrane studied increased.

11B shows the results of the same experiment, showing only 3 and lower pH ranges. This graph highlights that the effect of pH on hydration is not significant in the pH range below about 2.0. However, in the pH range from 2 to about 3, the hydration increases considerably with increasing pH. In addition, in the pH range of about 2 or less. Hydration is little dependent on pH; Increasing the pH from 1.3 to about 2 slightly increases the hydration of the membrane containing 4.4 Md PEO. However, at a pH of about 2 or higher, the effect of increasing the pH is higher than at pH 2 or lower. Without considering the PEO used, or the ratio of CMC to PEO, each membrane type exhibits a high dependence on the pH of at least two of hydration.

This result is unexpected in light of the prior art such as Smith's patent, which discloses that the hydration rates of CMC / PEO membranes at pH 1.25 are 16% and 18%.

Example 18 Solubility of CMC / PEO Membrane

In another experiment to study the solubility of CMC / PEO membranes in 0.9% NaCl, 77.2% CMC / 22.5% PEO (4.4 Md;), 50% CMC / 50% PEO (4.4 Md;) and 50% CMC / 50% PEO (300 kd; ▲) membranes were prepared. Each membrane was prepared at different pH values and after 5 days of immersion in 0.9% NaCl, the membrane was dried and weighed. The data is shown in FIG. 12 as a percentage of the original dry weight.

FIG. 12 shows that the 77.5% CMC membrane loses only about 35% of its initial dry weight during the 5 day soaking to have minimal solubility. In addition, at pH 2 and below, there was no change in solubility with pH. However, as the pH increased to 2.5 and above, the solubility of the membrane gradually increased. Membranes composed of 50% CMC dissolve better at each pH (at least 55% dissolved) than membranes composed of 77.5% CMC. Compared to the 77.5% CMC membrane, the membrane composed of 50% CMC shows that the solubility does not depend on pH below about 2.5. However, at pH above about 2.5, solubility increased with increasing pH.

Example 19 Bioadhesion of CMC / PEO Membrane

To further characterize the bioadhesive properties of the CMC / PEO membranes of the present invention, a bovine mesenteric loop coalescence system was used to reveal the relationship between membrane pH and bioadhesiveness. Fresh bovine mesentery was attached to a tacky platform and a CMC / PEO membrane loop to be used as an adhesive was fixed on the crosspiece of the device. The mesentery and membrane were moisturized and moistened, and the membrane loop was lowered to contact the mesentery. The force in grams was continuously monitored while raising the crossbar. The force when the membrane loop was separated from the mesentery was recorded. The force required to separate the membrane prepared at the pH between about 1.25 and about 4.25 from the mesentery was recorded.

13A and 13B show the results of the bioadhesive test using bovine mesentery. In FIG. 13A (77.5% CMC / 22.5 PEO, 4.4 Md;), the rembrane of pH 2,5 or less did not adhere well to the mesentery. However, as the pH increased above 2.5, the membrane adhered well to the mesentery and about 170 g of force was required for membrane separation at pH 3.0. Membranes composed of 50% CMC / 50% PEO (300 kd;) also did not adhere to bovine mesentery at pH below about 2.5. However, as the pH increased, the adhesion of these membranes increased. In contrast, membranes composed of 50% CMC / 50% PEO and 4.4 Md (▲) adhered at the lowest pH of 1.25, but increasing the pH to 2.5 decreased the adhesion to bovine mesentery. Surprisingly, increasing the pH above 2.5 showed the opposite trend and increased the adhesion to the mesentery to a very high degree, requiring about 250 g of force to separate the membrane from the mesentery at pH 3.0. In addition, as the pH increased further, the adhesion of two of the membrane series decreased, but in either case the bioadhesiveness did not decrease below the value seen at pH 2.5 of the membrane series.

13B summarizes data obtained for the study of 77.5% CMC / 22.5% PEO (4.4 Md) membrane. Data are expressed as mean ± standard error of the mean; n = 6 or 7. In one series shown in FIG. 13A, below pH 2.4, the membrane did not adhere well to the mesentery. However, increasing the pH above about 2.5 increased the adhesion significantly to the pH-dependent type, and the maximum force required for membrane separation from the mesentery was about 120 gms.

The results observed above pH 2.5 are completely unexpected in light of the results obtained below pH 2.0. CMC / PEO membranes made at pH ranges similar to those in Smith et al. Did not adhere well to biological materials and did not predict bioadhesive behavior of CMC / PEO membranes at pH above about 2.5.

Example 20: Effect on the Tackiness, Biocompatibility and Bioresorption of CMC / PEO Films

Introduction:

The purpose of this study is to first reveal the adhesion to various organs in the peritoneal cavity of a film comprising various combinations of polymethylene oxide (PEO) and carboxymethyl cellulose (CMC). The second purpose is to consistently use the biocompatibility of the same 5 films. The third object is to find out whether the film of the present invention can be reabsorbed.

Way:

2.4-2.7 kg, female, 20 New Zealand White rabbits were isolated for at least 2 days before surgery. On the day of surgery, rabbits were anesthetized with an intramuscular ketamine / xylazine injection and prepared for sterile surgery. Centerline laparotomy was performed and a 2 cm piece of film of the present invention was placed on the side wall, visceral and uterine horns. A wound performed other than an incision is the removal of the broad ligaments of the rabbit's uterine horn to allow the film to wrap on the uterine horn. After recovery, the rabbits were placed back in the vivaria. 24, 48, 72 and 96 hours after surgery, the rabbit was reopened at the incision to assess the location of the original material, the location of the material compared to the condition and the appearance of the tissue in contact with the material.

Film used:

The films studied were gamma-irradiated at a total dosage of 2.5 megaRads ("MRad"), 95% CMC / 5% PEO, pH 5.0 (Film #: 414), 60% CMC / 40% PEO, pH 2.0 and 95% CMC Bilayer membrane with 5% PEO, pH 5.0 layer (film number: 417), Bilayer membrane with 60% CMC / 40% PEO, pH 3.0 and 95% CMC / 5% PEO, pH 5.0 layer (film number : 418), 95% CMC / 5% PEO, pH 4.0 (film no .: 419) and 95% CMC / 5% PEO, pH 3.0 (film no .: 422). After insertion of the film, the abdominal muscle and skin were closed using a suture line containing 3-0 Dexon-II.

result:

Most of the material was absorbed into the horn's blood and combined with large clots throughout the observation. In case this is not the case, the following observations will be made. Overall, a small amount of inflammation was found to bind with the material in which it was placed. It will also indicate if inflammation or tissue damage is observed. At all times, inflammation was localized and very transient (appearing only 1 time point and 1 subject / time point).

A film comprising 95% CMC / 5% PEO, pH 5.0 (Film #: 414) was present in the batch site within 4 of 6 sites 24 hours after injection. 48 hours after injection, the material was present in 5 of 6 sites and broke in the intestines. After 72 hours, the material was only present in the horn (the material broke in one rabbit). In one rabbit at 72 hours some slight bleeding was observed in the intestines. After 96 hours, the material was in 3 of 6 sites. In one site, the material observed was gel.

A film comprising 95% CMC / 5% PEO, pH 4.0 (Film No .: 419) was present at 5 out of 6 sites at 24 and 48 hours. At 48 hours, the material present in the intestines was broken. In one rabbit, whitening and punctate bleeding were observed on the sidewalls. At 72 hours, material was present at 4 of 6 sites. The material on the viscera is broken. Gelled material was present in the gutter. At 96 hours, broken and / or gelled material was present at 5 out of 6 sites. In one rabbit, the material located in the horn did not bind to clots.

95% CMC / 5% PEO, pH 3.0 (film number: 422) was present at all sites 24 hours after injection. At 48 hours, material was present in 3 of 5 sites. Whitening (more severe at the center than the edges) was observed on the sidewall of one rabbit. Pointed bleeding on the viscera was observed in the same rabbit. At 72 hours, material was present at all sites. On the sidewalls and viscera, no material could be observed visually, and a smooth gelled coating was observed at the placement site. At 96 hours, intact fragments were observed on the horn and viscera of one rabbit. On the side walls of both rabbits and the viscera of the other rabbits, small fragments and smooth gels were present at the site of placement.

A bilayer membrane (film number: 417) comprising 60% CMC / 40% PEO, pH 2.0 and 95% CMC / 5% PEO, pH 5.0 layers was located at 4 of 6 sites. This time, some inflammation was observed in the intestine of one rabbit. At 48 hours, material was observed at 3 of 6 sites (broken in the intestines). At 72 hours, the material was in 3 of 6 sites and inflammation was observed in the side walls of the two rabbits. At 96 hours, fragments were observed at 5 out of 6 sites. In the horn, no coagulation with material was observed. Intestinal inflammation and punctate bleeding were observed.

A bilayer membrane (film number: 418) comprising 60% CMC / 40% PEO, pH 3.0 and 95% CMC / 5% PEO, pH 5.0 layers was present at all sites at 24 hours. Some inflammation was observed on the side wall of one rabbit. At 48 hours, material was observed at 5 of 6 sites (gel at 3 of these sites). At 72 hours, material was present in 5 of 6 sites (gel at 4 sites). In one rabbit, pointed bleeding and wounds were observed on the sidewalls (inflammation observed at 24 hours in the same rabbit). At 96 hours, the material fragment was in 5 of 6 sites. For kgs rabbits, the material of the horn did not bind to clots.

conclusion:

The study shows that both monolayer and bilayer membranes of the present invention adhere to rabbit peritoneal tissue. The study also shows that the film is biocompatible and maintained during the time period in the subject body, and some films are removed from the surgical site by the subject's physiological process.

Example 21 Evaluation of Films of the Invention in Preventing Abdominal Adhesion Formation

Introduction:

The purpose of this series of studies is to test the efficacy of the film of the present invention on abdominal adhesion formation in the rabbit model of adhesion formation between the sidewalls, caecum and viscera.

Way:

1. Test Subject

40 female New Zealand white rabbits from 2.4 to 2.7 kg were purchased and quarantined for at least 2 days prior to use. The rabbits were housed in a 12:12 light: dark cycle with food and water at random.

2. Material

The films studied were bilayer films consisting of 95% CMC / 5% PEO, pH 5.0 and 60% CMC / 40% PEO, pH 2.0 layers, gamma irradiated with a total gamma dose of 2.5 MRad (film no .: 438), 95% CMC Bilayer film comprising 5/5 PEO, pH 5.0 and 60% CMC / 40% PEO, pH 3.0 layers (film no .: 437) and monolayer film comprising 95% CMC / 5% PEO, pH 4.0. . The suture used to suture the peritoneum and skin is a 3-0 coated Dexon II suture (Davis and Geck, Manati, PR).

3. Sidewall Models of Adhesion Formation

Rabbits were anesthetized by intramuscular injection with a mixture of 55 mg / kg ketamine hydrochloride and 5 mg / kg Rompus. After preparation for sterile surgery, centerline open was performed. The cecum and intestines were removed from the body and digital pressure was applied to cause subserosal bleeding on all surfaces. The intestinal damage is then lightly peeled off using 4 "x 4", 4-ply sterilized gauze until bleeding is stopped. Then, the cecum and intestines are placed in their normal anatomical position. The peritoneal and abdominal transverse muscles 4 × 3 cm wide are removed from the right lateral abdominal lining. The film is placed on the sidewall wound. After 7-8 days, the rabbits died and the percentage of sidewall wound area with adhesion was measured.

In addition, the adhesion of coalescence was calculated using the following system:

0 = no coalescence

1 = smooth, easily ablation coalescence

2 = moderate adhesion; Unrestrainable, not damaging organs

3 = strong adhesion; Uncontrollable, damage to organs upon removal

The reduction in both the area of adhesion and adhesion is believed to be advantageous.

result

In 10 control rabbits, 5 showed various adhesions at 20-80% area of the sidewalls. The other five rabbits showed no adhesion. However, there was no evidence of adhesion at any of the sites with anti-adhesion membranes.

Example 22 Evaluation of CMC / PEO Films in Prevention of Abdominal Adhesion Remodeling

Introduction

1. Test Subject

110 female New Zealand white rabbits, 2.4-2.7 kg, were purchased from an Irish farm (Norco, CA) and sequestered in USC Vivalria for at least two days prior to use. The rabbits were housed in a 12:12 light: dark cycle with food and water at random. Rabbits with adhesions and no symptoms of subcutaneous infection were used in the disassembly portion of the study.

2. Material

The CMC / PEO films used in this study consisted of 95% CMC / 5% PEO, pH 4.0 (film no .: 603), 95% CMC / 5% PEO, pH 5.0 and 60% CMC / 40% PEO, pH 3.0 layers. Bilayer films (film no .: 605) comprising the constructed bilayer film (film no .: 604) and 95% CMC / 5% PEO, pH 5.0 and 60% CMC / 40% PEO, pH 2.0 layers were included. The film contains FD & C Blue Dye No 2 and was sterilized by exposure to gamma rays (total dose 2.5 MRad). In a separate experiment, a film (film number: 627) containing 77.5% CMC / 22.5% PEO, pH 4.2 and Blue Dye No 2 was studied. Adhesion prevention in the transplanted subject with the membrane with the composition was compared to a control subject without any anti-adhesion membrane implanted. After implantation of the membrane, the suture used to suture the peritoneum and skin is a 3-0 coated Dexon II suture (Davis and Geck, Manati, PR).

Sidewall Model of Adhesion Remodeling

Rabbits were anesthetized by intramuscular injection with a mixture of 55 mg / kg ketamine hydrochloride and 5 mg / kg Rompus. After preparation for sterile surgery, centerline open was performed. The cecum and intestines were removed from the body and digital pressure was applied to cause subserosal bleeding on all surfaces. The intestinal damage is then lightly peeled off using 4 "x 4", 4-ply sterilized gauze until bleeding is stopped. Then, the cecum and intestines are placed in their normal anatomical position. The peritoneal and abdominal transverse muscles 4 × 3 cm wide are removed from the right lateral abdominal lining. The incision was closed in two layers using 3-0 Dexon II. After midday, the subjects were anesthetized as described above and a second open surgery performed. In rabbits with adhesions, adhesions are calculated and separated using dull, sharp anatomy. Be careful not to damage the intestines.

3. Implantation of Anti-Adhesion Film

The selected film is placed at the site of adhesion. After 7-10 days, rabbits were killed and the percentage of sidewall wound area accompanying adhesion was measured as described in Example 21 above.

result

The results of this study are shown in Tables 14-16. All of the CMC / PEO films studied were very effective in reducing adhesion remodeling. These data are shown in Table 14 (Adhesion Remodeling Area) and Table 15 (Incidence of Adhesion Remodeling).

The membrane composition is shown as% CMC /% PEO, pH and the bilayer membrane is shown as a two layer composition. Data is expressed as mean ± standard deviation.

These experiments show that bilayer CMC / PEO films significantly inhibit adhesion remodeling.

Data is expressed as mean ± standard deviation.

Monolayer film # 627 increased the number of specimens without adhesions from 0/11 to 8/10. The study shows that monolayer CMC / PEO films significantly reduce the incidence and severity of coalescence remodeling.

Example 23 Intradermal Reaction of CMC / PEO Films

Introduction

The purpose of this test is to assess the potential for the test material to cause irritation after injection into rabbit skin.

Way

1. Test Subject

As in the above example, New Zealand white rabbits were used in this study. The rabbit is a species required by the current version of the International Organization of Standardization. These were obtained from Grimawood Farm (California, Stockton, CA). Three female adults, each weighing between 2.2 and 2.3, were used. They were set aside while maintaining a relative humidity of 16-22 ° C. and 50 ± 20%. They were given an experimental rabbit diet (about 200 g / day) and water freely, and the light: dark cycle was 12:12.

2. Sample Manufacturing:

For SCI extraction, sterile dry glass tubes with screw caps are filled with 20 ml of appropriate extraction stock. Gamma (2.5 MRad) Two cohesive film samples (both surface exposed) of 120 cm ² total surface area irradiated were cut into pieces and placed in tubes. Another sterile tube was filled with an equal volume of 0 stock and used as a blank. Each sample and blank were extracted at 37 ° C. for 72 hours. For even distribution of the extract, each extract was shaken vigorously before taking the dose.

3. Injection Protocol

On the day of testing, the hairs on both sides of the spinal column of the back of each rabbit were removed. 0.2 ml of one sample extract in each of the three rabbits was injected into each of five sites along one side of the spinal column. 0.2 ml of a blank (with salinity) corresponding to each of the three rabbits was injected intradermal, respectively, into five sites along the other side of the spinal column. Erythema, eschar formation, edema and debris were observed at the injection site immediately after injection and scored at 24, 48 and 72 hours.

4. Evaluation of results

Daily health signs of all subjects were observed daily. At 24, 48 and 72 hours post infusion, all tissue responses such as erythema, eschar formation, edema and deaeration at the injection site were investigated and scored. For each specimen, individual stimulus scores of erythema and edema were added to each time point of each test extract, respectively, and then divided by 10 (total number of observations). The injection site of the control group was also evaluated in a similar manner. Then, the primary stimulus score of each time point was obtained by subtracting the average stimulus score of the control from the average stimulus score of the test material. After that, the primary stimulus scores of each specimen were added and divided by the total number of specimens to obtain a primary stimulation index (PII). Then, the primary stimulus corresponding to the trial material was measured.

The methods used in this study are standard in the art and include NU SOP 16G-43, Intracutaneous Reactivity Test (ISO) , AAMI Criteria and Recommended Experiments, Vol. 4; Biological Evaluation of Medical Instruments [Biological Evaluation of Medical Devices (1997)] pp. 255-256, and USP 23 [1995] pp. 1699-1702.

result

The subjects were healthy throughout the test period. No irritant response was observed in any of the subjects injected with saline. Erythema was observed in only 5 of the 15 sites injected with test material, but very mild, with a score of about 1. Edema was not observed in any of the subjects after injecting the test material. The primary stimulus scores and the primary stimulus index are shown in Table 19. The primary stimulus index (PII) of the test material extracted from SCI was zero.

Example 24 Effect of Film Transplantation on Gross and Histopathology

Introduction :

The purpose of this study was to investigate the effects of 10-20 times the expected clinical infusion of the CMC / PEO film of the present invention on the microscopic forms and gross of liver, kidney, bladder, visceral, abdominal wall, heart, lung and uterus. To measure.

Way:

1. Test Subject:

Twelve female New Zealand white rabbits, 2.4-2.7 kg, were quarantined for at least two days prior to use. Rabbits were allowed to eat food and water arbitrarily and housed at light: dark cycle 12:12.

2. Material:

Gamma (2.5MRad) Surgically implanted in the peritoneal cavity of irradiated CMC / PEO film (55.2 cm ² (10 × expected dose) or 110.7cm ² (20 × expected dose / rabbit). To suture the peritoneum and skin Sutures used are 3-0 coated Dexon II sutures (Davis and Geck, Manati. PR).

3. Sidewall Models:

Adhesion was induced using the method as described above in Example 21.

4. Evaluation of Results:

After 7 days, the rabbits were killed and all injuries of the abdominal tissues were comprehensively evaluated. Kidneys, spleen, liver, lungs, heart, intestines, abdominal wall and uterus (in addition to all products with total damage) were preserved in formalin and prepared for histopathological evaluation.

result:

CMC / PEO films inhibited adhesion formation of damaged sidewalls. This was consistent with previous studies described in the above examples, showing the maximum effect of this barrier in the sidewall formation model. No gross damage was found at autopsy. In the microscopic observation of tissues collected according to the protocol, no microscopic damage was found. In spleen, macrophages were found with the injected material in two groups of specimens implanted with the membrane of the present invention. This was more pronounced in the specimens that had been implanted with higher amounts of film. This reflects the biological removal mechanism of the CMC / PEO membrane at this postoperative time point.

Example: Effect of CMC / PEO Membrane on Abscess Formation in Rabbits

Introduction

A host resistance model was used to determine whether transplantation of the CMC / PEO film according to the invention, performed concurrently with bacterial inoculation, affected death and abscess formation as a result of infection. The purpose of this study is to determine whether there is an increased risk associated with the use of these products in potential infections.

Way

1. Test Subject:

90 female Sprague Dawley rats, 175-225 gms, were used in this study. Ten were used for fecal production. Twenty animals were used to evaluate the new shares of materials LD ₁₀ and LD ₅₀ and 60 animals were used for stability studies. Rats were acclimated for at least 2 days before surgery. Rats were housed in USC Vivarium (AALAC verified / approved) at 12:12 hour light / dark cycles. Except immediately after the interval, food and water could be eaten at random.

2. Preparation of Gelatin Capsules:

Excretion contents and excretion were taken from rats fed hamburgers for 2 weeks and mixed 1: 1 with sterile peptone yeast glucose juice free of Scott Laboratories and containing 10% barium sulfate. The amount of these excretion preparations derived from rats (25 μl-LD ₁₀ ) with mortality 0-20% or rats with 75-60% (75 μl-LD ₅₀ ) was measured in 20 rats. Appropriate amount of material was aseptically added to the gelatin capsule (No. 1, Eli Lily Company). This capsule was then placed in a larger secondary capsule (No. 00, Eli Lily Company). This was called a double-walled gelatin capsule. The capsules were prepared one week before transplantation, isolated until the day of surgery, and stored frozen.

3. Manufacture of film:

The film irradiated with gamma ray (2.5 MRad) for each rat was cut into 1.5 x 1.5 cm pieces.

4. Transplantation of Gelatin Capsules:

Rats were operated in a standardized procedure of laparotomy (anesthesia with ketamine / rompus, hair removed with animal clipper, betadine wash, alcohol wash). The centerline was incision 2 cm. Double wall gelatin capsules were injected into the right side of the abdomen through the incision. In the control group, no further treatment was performed. For subjects treated with gelatin capsules containing CMC and PEO, the capsules were injected on the left side of the abdomen between the viscera and the peritoneum.

Four groups of 15 animals each were studied, two control groups injected LD ₁₀ and LD ₅₀ , respectively, and two groups received implant devices comprising LD ₁₀ or LD ₅₀ and CMC / PEO. Then, two layers of 4-0 Echicon sutures were used to suture the abdominal cavity and skin. After surgery, rats were given painkillers for 3 days and morbidity / mortality was observed twice daily.

5. Autopsy:

Rats that died during the 11-day observation period were autopsied to confirm the presence of an acute bacterial infection. Rats surviving the initial acute infection were killed 11 days after surgery, and the smell of the open abdomen of each rat and the presence of abdominal abscess touched through the skin were observed. In addition, four sites of the peritoneum were tested for abscess production. These sites include the liver, abdominal wall, intestines and the tabernacle. Abscesses were scored at each site as follows:

Score Description

0 abscess does not exist

0.5 one very small abscess present

1 small abscess

2 presence of medium-sized abscess

3 large or several medium size abscesses present

4 one very large or several medium size abscesses present

The scoring was performed in a mechanical manner with two separate observations and the scores recorded.

result:

Administration of CMC / PEO material with bacterial peritonitis did not affect rat survival after infection. The results of these studies are shown in Table 20 below. In the group injected with LD ₅₀ , 9 of 15 survived, and in the group injected with LD ₁₀ , 13 of 15 survived.

In general, specimens injected with a large amount of abscess-inducing bacteria showed higher rates of abscess formation than those injected with a small amount. The CMC / PEO mixture did not change the formation of abscesses even in the bacteria-injected specimens.

Example 26 Surface and Blood Contact of CMC / PEO Films

Introduction:

The purpose of this study is to find out whether the CMC / PEO membrane of the present invention has anti-thrombogen properties. CMC (700 kd) and PEO (4,4 Md) were mixed and a thin film made of the mixture. The bilayer film had about the same thickness as the single layer film. In addition, in the bilayer film, the other layers had almost the same mass. The surface and blood compatibility of the film was evaluated. Platelet adhesion and activation, and plasma remineralization (fibrin clump formation) time analysis were performed on these film samples using scanning electron microscopy (SEM), chemical analysis electron spectroscopy (ESCA). Film A is a non-radiated bilayer film comprising 95% CMC / 5% PEO on the first side and 60% CMC / 40% PEO on the second side. Film B is the same as Film A except that it is spun. Films C and D have 77.5% CMC and 22.5% PEO and are non-spun and spun monolayer films, respectively. Film E is a control film composed and spun at 100% CMC.

Way:

1. Scanning electron microscopy:

Scanning electron microscopy (SEM) for observing film surface and cross-sectional morphology was obtained from the Electron Microscope Center of Northeastern University, Boston, MA. Film samples were snap frozen in liquefied nitrogen and cut to obtain clean pieces for observation of yellow cross sections. The sample was fixed on an aluminum sample mount and spray coated with a thin film of gold and palladium. Film samples were observed with an accelerating voltage of 10 kV at a 10 mm working distance using an AMR-1000 scanning electron microscope (Amray Instruments, Bedford, MA). The original magnifications of the film surface and the cross-sectional image were 5,000 × and 2.000 ×, respectively.

2. Electron spectrometer for chemical analysis

Electron spectroscopy (ESCA) for chemical analysis is a surface analysis technique that measures atomic composition and maps functional groups to surface surfaces of layers of 100 GHz or more. This technique is useful for measuring the PEO surface presence of CMC / PEO membranes (BD Ratner et al., Surface Studies by ESCA on Polymers for Biomedical Application.WJ Feast and Hs Munro (eds), which are hereby incorporated by reference ). Polymer Surface and Interfaces.See Jhon Wiley and Sons, New York, NY pp: 231-251 (1987). ESCA was performed at the National ESCA and Surface Analysis Center (NESAC / BIO) of Biomedical Problems and analyzed at the center. Film samples were analyzed by a Surface Science Instrument (SSI, Mountain View, CA) ESCA instrument equipped with an aluminum _Ka1,2 X-ray source. The typical pressure of the sample chamber during the acquisition of the spectra was 10 ^-9 Torr. Surface atomic composition of carbon (C1s) and oxygen (O1s) was calculated from wide scan analysis and peak zone md using SSI data analysis software. In addition, high resolution analysis by peak-fitting for measuring identity of chemical functional groups was performed using SSI software. The surface charge was minimized using an electron outlet gun set at 5.0 eV. The binding energy scale was referenced by setting the -CH (hydrocarbon) peak maximum of the C1s spectrum to 285.0 eV.

3. Platelet adhesion and activation:

Platelet adhesion and activation measurements were performed as described above (M. Amiji, Permeability and Blood Copatibility Properties of Chitosan-Poly (ethylen oxide) Blend Membranes for Hemodialisis.Biomaterials 16 : 593-599 (1995), M.Amiji, Surface Modification of Chitisan Membranes by Complexation-Interpenetration of Anionic Polysaccharides for Improved Blood compatibility in Hemodialysis.J. Biomat.Sci.Polym.Edn. 8 : 281-298 (1996), both papers incorporated by reference). In brief, platelet observation chambers consist of film-coated clean glass slides, 2 polyethylene spacers, and glass coverslips. After being informed of consent, human blood from a healthy adult volunteer was taken in a heparin-containing excretory container (Vacutainers). ^{??, Becton-Dickinson, Rutherford,} NJ). Heparinized blood was centrifuged at 100 g for 10 minutes to obtain platelet-rich plasma (PRP).

200 μl of PRP was dropped into the platelet observation chamber. Platelets in PRP were allowed to stick and activate at room temperature for 1 hour on the polymer surface. The chamber was washed with phosphate-buffered saline (PBS, pH 7.4) to remove non-stick platelets and plasma proteins. Sticky platelets were fixed in PBS with 20% (w / v) glutaraldehyde solution. After washing with PBS, platelets were stained with 0.1% (w / v) Coomassie Brilliant Blue (Bio-Rad, Hercules, CA) staining solution for 1.5 hours. Nikon Labophot stained platelets Observations were made at 40 × magnification using a II (Melville, NY) optical microscope. Images of sticky platelets Hamamatsu CCD Sony Trinitron using a camera (Hamamatsu-shi, Japan) Transferred to video display. Hamamatsu Argus-10 ^?? The image processor was used to calculate the number of platelets per 25,000 μm ² of all observation fields. This data represents the mean of cohesive platelet count ± SD in at least 12 observation fields and 2 independent tests.

The expansion of platelet activity was qualitatively determined from the spreading behavior of adherent platelets as described above in Table 10.

4. Plasma Remineralization Time:

The remineralization time of plasma is measured as the length of time required to form fibrin aggregates in calcium-containing citrated plasma in contact with the surface of interest. This is a useful marker of intrinsic coagulation. Human blood was collected in collecting containers (Vacutainers, Becton-Dickinson) in the presence of sodium citrate buffer as anticoagulant. Citrated blood was centrifuged at 2,500 g for 20 minutes to obtain platelet-deficient plasma. Circular portions (20 mm diameter) of the control and CMC-PEO films were cut with a surgical scalpel. Film section is 12-well tissue-cultured polystyrene (TCP, Falcon , Becton-Dickinson) microplates were hydrated with 2.0 ml PBS for 10 minutes. Excess PBS was removed by inhalation.

The plasma remineralization time of citrated plasma in contact with the control and CMC-PEO mixed films is shown in Brown (Brown, Hematology; Principles and Procedures, Sixth Edition, Lea and Febioger, Philadelphia, PA, 1993, 218, here for complete reference). Measured according to the method described herein. Briefly, 1.0 ml of citrated plasma was mixed with 0.5 ml of 0.05 M calcium chloride and the hydrated film sample was incubated at 37 ° C. in a bath. Occasionally, samples were removed from the bath and shaked slowly. The time required to form fibrin aggregates was recorded. This figure indicates the mean time ± S.D of plasma remineralization obtained in a separate independent study.

result:

1. SEM Analysis:

14-20 are SEM images of the surface and cross section of the seven film samples (A through E), using the original magnification of 5,000 × (surface) and 2,000 × (cross section). The image of FIG. 14A (Film A, face 1; 95% CMC / 5% PEO; irradiated) is from a bilayer film and shows a portion of the surface of face 1 having a significant sawtooth shape. This serrated shape may be due to the incorporation of PEO, although not intended to limit the invention to this particular theory. Other theories can explain this observation. Image 14b of the cross section shows a clear boundary between the two sides of the thin valve. The top of the membrane shown in the upper right corner of FIG. 14B (95% CMC / 5% PEO) is relatively smooth compared to the other side indicated in the lower right corner of FIG. 14B.

The image of FIG. 15A (Film A, face 2; 60% CMC / 40% PEO; irradiated) shows the characteristic “bumps” that can be obtained due to the high concentration of PEO on this side of the bilayer membrane. An image of the cross section (FIG. 15B) shows plane 2 in the upper portion of the picture. This image displays a more “spongy” or porous structure at the top of the picture, which may be due to the merging of PEOs. In these films, the PEO chains are homogeneously mixed and the film components do not separate into separate phases.

In contrast, the images of FIGS. 16 and 17 (Sample B, faces 1 and 2, respectively) are of the same film as Film A, except that they are not irradiated. FIG. 16A shows face 1 (95% CMC / 5% PEO) and FIG. 16B shows the cross section of the film, the lower right side of the photograph of face 1 and the upper part of face 2 (60% CMC / 40% PEO) to be. The morphology of the surface and cross section of these films did not differ significantly compared to their investigated counterparts. All bilayer membranes marked separate separation zones containing low (5%) and high (40%) content of PEO.

17A shows Sample B side 2 (60% CMC / 40% PEO; not irradiated) in the top field of view of the surface. 17A shows a cross section of film B. FIG. The lower right part of the photo is cotton 1 (95% CMC / 5% PEO) and the upper left is cotton 2 (60% CMC / 40% PEO).

18 and 19 (films C and D, respectively) are images of a film prepared by combining CMC and PEO at a weight ratio of 77.5: 22.5. Sample D (FIG. 19) was not irradiated while Film C (FIG. 18) was irradiated. In FIG. 18A, the surface image shows "grains" distributed over the surface of the film. This "grainy" may occur because some PEO is filtered out of the surface. The image of the cross section (FIG. 18B) shows a “spongy” or porous film.

19A also shows a grain shape on the surface. The cross sectional image in FIG. 19B represents the cavernous film. With film A of two layers, gamma irradiation does not significantly affect the shape of mixed film C.

20 (Film E) is a 100% CMC film that is not gamma-irradiated. The surface (FIG. 20A) and the cross section (FIG. 20B) of this film are smooth. The smoothness of the surface and cross section of the film E may be due to the high crystallinity in the CMC film. The high crystalline material can form a film without porosity. However, other mechanisms can affect the smoothness of this film.

2. Surface Chemical Analysis:

ESCA provides the composition of surface elements and identifies chemical functional groups up to a 100 μs-thick surface layer. Extensive scanning analysis maps the composition of an element according to its individual binding energy in the spectrum. For example, carbon (C) has a binding energy of about 280-290 eV. High resolution analysis of the component spectra can provide additional information on functional functionalities associated with the component of interest. In the C1 spectrum, -CH- (or hydrocarbon) functionality may be associated with a binding energy of 285.0 eV. In contrast, -CO- (ether) functionality is associated with a binding energy of 286.4 eV (M. Amiji. Synthesis of Anionic Poly (ethylene glycol) Derivative for Chitosan Surface Modification in Blood-Contacting Application.Carbohyd.Polym . 32 : 193- 199 (1997), hereby incorporated by reference). Since the ethylene oxide residues of PEO have -CO- functionality, any change in the high resolution spectra can indicate an increase in -CO- composition due to the presence of PEO chains on the surface of the film. This may be consistent with increased surface access of the PEO chain. Surface accessibility of the PEO chain is important because it inhibits the adhesion of plasma proteins and the adhesion and activation of platelets. One theory explaining these observations is that PEO interferes with the adsorption of plasma proteins through steric repulsion mechanisms (M.Amiji et al., Surface Modification of Poymeric Biomaterials with Poly (ethylene oxide), Alnumin, and Heparin for Reduced Thrombogenicity) In S, L, Cooper, CHBamford, and T. Tsuruta (eds.) Polymer Biomaterials: In Solution, as Interfaces, and as Solids.VSP, The Netherlands, 1995, pp535-552; M.Amiji et al., Surface Modification of Polymeric Biomaterials with Poly (ethylene oxide) : A Steric Repulsion Approach , In SWShalaby, Y. Ikada, R. Langer, and J. Williams (eds.) Polymers of Biological and Biomedical Significance , ACS Symposium Series Publication, Volume 540. American Cehmical Society , Washington, DC. 1994, pp 135-146, hereby fully incorporated by reference). However, other theories can explain the anti-thrombotic effect of the membranes according to the invention, and these theories are also considered as part of the invention.

Surface analysis results of the control group and the CMC-PEO film described above in FIGS. 14-20 are shown in Table 21.

^a ESCA was conducted at the National ESCA and Surface Analysis Center for Biomedical Tasks at the University of Washington (Seattle, WA).

Table 21 shows that Na and Cl appear in most all films. In non-irradiated films B and D, the contribution from Na and Cl was significantly higher than in irradiated films A and C. The presence of some N on film can indicate contamination in that nitrogen is generally not present in the film. Proteins and other nitrogen-containing impurities in the film can be of nitrogen origin. An increase in the O composition is noticeable in plane 2 and film C of films A and B. This is due to the high concentration (40%) of PEO present in these samples as compared to face 1 of films A and B (only 5% PEO).

Film D (77.5% CMC / 22.5% PEO; non-irradiated) indicates the presence of Na and Cl. The presence of Na and Cl can distort the percentage contribution from other components, specifically from C and O. Thus, the lack of a high O peak in film D can be seen not because of the low amount of O present in the film but because of the presence of artificial Cl in this sample.

100% CMC film (Film E) has 69.3% C, 17.4% O, 7.7% Na and 5.6% Cl. A high percentage of C in this spectrum and a correspondingly low percentage of O means that the large amount of O shown in the other films is due to the presence of PEO.

To determine the type of bond present in the other films, high resolution Cls, Ols and Nls spectral analyzes were performed by peak-matching a wide range of scan peaks (Table 22).

As shown in Table 22, 42% carbon in Film A, Cotton 1 (95% CMC / 5% PEO) is bonded to hydrogen (-CH) or other carbon atoms (-CC-), and 42% is oxygen ( -CO-) and 13% double-bonded to oxygen (-C = O). Higher percentages of ether carbon-bonding moieties (—C—O—) than those observed in 100% CMC film (film E) indicate that ethylene oxide residues are present on these surfaces. The carboxyl (-C = O-) peak at 13% is due to the neutralizing carboxylic acid group of CMC. Ols peaks in Film A, face 1, are analyzed with two peaks associated with -O = C- and -O-C- functional groups.

The Nls spectrum is due to the -N-H- functional group due to the possibility of contamination of film A, face 1 by the protein. The presence of PEO on the surface of film A, face 2 (60:40, CMC-PEO) is supported due to the presence of Cls peaks, which is due to ether carbon bonds (C-O). In addition, Ols analysis also indicates that there is a high percentage of —O—C— bonds in face 2 compared to face 1. Face 2 of Films A and B has a similar surface bonding profile. There was no significant difference in the surface bonding structure of the irradiated film to the non-irradiated film.

Cls and Ols spectra in C and D monolayers (77.5% CMC / 22.5% PEO) are also associated with -C-O- or -O-C- bonds, pointing to PEO chains on the surface of these films. The Nls spectrum observed in film D is due to contamination by the protein and exhibits -N-H- functional groups. In the control 100% CMC film (Film E), 70% of the Cls shell is due to -C-H-, 21% because of -C-O- and 6% because of -C = O-. In addition, the Ols peak is analyzed as two peaks with 27% -O = C- and 73% -O-C-.

This result indicates the presence of PEO on the surface of these films. Increasing the PEO concentration in the film composition increased the concentration of PEO on the surface. In addition, there were no significant differences in the composition of the surface elements or the types of functional groups due to irradiation.

3. Platelet adhesion and activity:

Platelet adhesion and activity are important indicators of blood-biomaterial interactions (Hoffman, Blood-Biomaterial Interactions : An Overview.In SLCopper and NAPeppas (eds.). Biomaterials: Interfacial Phenomena and Applications.Volume 199. American Chemical Society , Washington, DC 1982 pp 3-8, hereby incorporated by reference in its entirety). The initial number of adherent platelets and the extent of platelet activation on the surface of the biomaterial are associated with potential long-term blood-compatibility profiles (Baier et al., Human Platelet Spreading on Substrata of Known Surface Chemistry . J. Biomed. Mater. Res. 19: 1157-1167 (1985), hereby fully incorporated by reference). Upon contact with the polymeric surface, platelets retain their disk form present in the early dormant phase and the development area is typically 10-15 μm ² . When activated, platelets expand their limbs and initiate the release of granular contents. During the partial activation step, the spreading area of platelets may increase to about 35 μm ² . When platelets are fully-activated, they contract the limbs to form a circular or "pancake" shape and the area of development extends to 45 or 50 µm ² (Park et al., Morphological Characterization of Surface-Induced Platelet Activation . Biomaterials 11 : 24-31 (1990) , Where it is fully referenced by reference). The developmental profile of activated platelets has been used by Lin et al to cause five levels of activation (Lin et al., Polyethylene Surface Sulfonation: Surface Characterization and Platelet Adhesion Studies . J. Coll. Interface. Sci. 164 : 99-106 (1994), Completely by reference). Clean glass promotes platelet adhesion and activation (Park et al., The Minimum Surface Fibrinogen Concentration Necessary for Platelet Activation on Dimethyldichlorosilane-Coated Glass. J. Biomed. Mater. Res. 25 : 407-420 (1991), hereby fully referred to. Related to).

The range of platelet adhesion was measured by counting the number of platelets per 25,000 μm ² target. The activation of surface-induced platelets was measured qualitatively from the developmental action of adherent platelets shown in Table 23.

As shown in Table 23, platelets adhered to and activated on the glass surface. However, platelets did not adhere in large numbers to the CMC / PEO membrane and were not activated to the same extent by glass. The degree of adhesion and activation was inversely proportional to the PEO concentration. Thus, increasing the amount of PEO reduced both platelet adhesion and activation. In addition, gamma irradiation did not affect platelet adhesion and activation when comparing films A and C (irradiated) to films B and D (non-irradiated).

Platelet adhesion and activation studies have shown that increased surface PEO has been associated with decreased platelet adhesion and activation. Based on this observation, CMC-PEO membranes with high content of PEO are relatively non-thrombotic.

4. Remineralization time of plasma:

The recalcification time of plasma is a measure of the intrinsic aggregation mechanism (Renaud, The recalcification plasma clotting time.A vlauable genaral clotting test inman and rats. Can . J. Physiol. Pharmacol. 47: 689-693 (1969), where complete Related by reference). Since the time required for plasma activation after contact varies with the type of surface, plasma remineralization time is used as an initiation factor for blood compatibility of biological material (Rhodes et al., Plasma recalcification as a measure of the contact phase activation and heparinization efficacy after contact with biomaterials Biomaterials 15:. 35-37 also as a relationship (1994), wherein reference is completely). Plasma remineralization times were measured using the methods described above by Renaud and Rhodes. Tissue cultured polystyrene (TCP) surfaces were generated by treating polystyrene microplates with oxygen plasma to convert the hydrophobic surfaces to hydrophilic surfaces. The results of this study are shown in Table 24.

^a Calcium-containing citrated human plasma was used to measure the time required to form fibrin aggregates in minutes.

^b Tissue-cultured polystyrene (TCP) 12-well microplates were used as controls.

^c Mean ± SD (n = 4)

The contact activation time on TCP was about 6.3 minutes and 5.6 minutes on 100% CMC (Film E). This is similar to the contact activation time irradiated on the previous clean glass surface. On the other hand, the plasma remineralization time on the PEO-containing film (Film A-D) was significantly higher than the control TCP or CMC surface. Remineralization time correlates with an increase in the PEO content of the film, and an increase in the PEO results in an increase in the remineralization time. Thus, the contact activation of plasma decreases considerably with increasing amount of PEO in the membrane.

conclusion

Films with an increased amount of PEO on the surface have anti-thrombogen properties and can inhibit the formation of fibrin clumps on the surface of the film. The anti-thrombogen effect depends on the amount of PEO. Thus, the production of films with increased PEO content can reduce thrombogenity.

Example 27 Bioresorption of CMC / PEO Membranes

Bioresorbability of the CMC / PEO membrane is measured by surgical incisions in the hind legs of the rat and injection of a portion of the CMC / PEO membrane into the muscle layer. Several membranes with different compositions or degrees of crosslinking were inserted into each specimen and the incision was closed. A significant number of test specimens were used for each type of membrane. Every day thereafter, the subject was sacrificed, and the incision was opened again to observe the original degree and position of the remaining membrane. The membrane was removed, excess water was removed, the wet bed was weighed, dried again, and weighed again. The amount of fluid absorbed, the amount of remaining solids and the shape of the membrane were observed. Comparisons were made between the original time length, tissue location, membrane composition, pre-incision state, and resorption rate. The membrane of the present invention was made to have the desired bioresorbability.

Example 28 Preparation of Iron 30% Ion-Binding Gels

9.5 g of dry powder CMC (ds-0.82), to prepare a gel comprising 2% w / v solids ratio and 95% CMC / 5% PEO, in one embodiment of the ionically crosslinked gel of the present invention Was weighed and mixed with 0.5 g of dry powder PEO (MW = 8,000d). A beaker was then prepared with 500 ml of deionized water and 3.2 ml of a 25.2% w / v FeCl ₂ .6H ₂ O solution. The dry powder CMC / PEO mixture was then slowly added to the beaker containing the iron chloride / water solution while stirring the solution at high speed. Once the dry ingredients were mixed into the solution, the stirring speed was lowered and the gel was mixed for 30-50 minutes until homogeneous.

The osmoticity was then adjusted to about 300 mmol / kg physiologically acceptable value by adding about 13 ml of 30% w / v sodium chloride solution and further mixing the gel. After another 15 minutes of mixing, the pH was adjusted to 7.0 by adding 1.7 N ammonium hydroxide. Then sterilized in autoclave at 250 ° C. for 15 minutes.

Example 29 Preparation of Ammonium 30% Ion-Binding Gel

In order to prepare a gel crosslinked with aluminum (Al ³⁺ ), the above example was added except that 3.2 ml of stock 22.5% w / v AlCl ₃ .6H ₂ O solution was added instead of the addition of the iron-containing solution. The same procedure as described for 28 was carried out. Like the iron crosslinked gel, the pH was adjusted to 7.0 using 1.7 N ammonium hydroxide. Then sterilized in autoclave at 250 ° C. for 15 minutes.

Example 30 Preparation of Calcium 30% Ion-Binding Gels

To prepare a gel crosslinked with calcium (Ca ²⁺ ), except for the addition of iron or aluminum-containing solution, 3.2 ml of stock 20.6% w / v CaCl ₂ · 2H ₂ O solution was added above. The same procedure as described in Examples 28 and 29 was carried out. Calcium-bound gels did not require any pH control after preparation. Then sterilized in autoclave at 250 ° C. for 15 minutes.

Example 31: Viscosity of CMC / PEO Ion-Binding Gels

After their preparation, the gel was equilibrated at 25 ° C. in a water electrolyzer. The viscosity of the gel was measured by standard methods. 25 ° C. using a viscometer (Brookfield Digital Viscometer, Model DV-II) and using the guidelines known in the booklet Cellulose Gum , Hercules, Inc., Wilmington, DE, p28 (1986), hereby incorporated by reference. The viscosity of the CMC (7HF, 700 kd) / PEO solution was measured at. In summary, the composition of the solution to be tested was selected and, with reference to Table I on page 29 of the Cellulose Gum , the spindle number and spindle rotation speed were selected. The viscosity of the gel not autoclaved was measured within 2 hours after the solution was stirred. The viscosity of the autoclaved gel was measured after equilibration at 25 ° C. The spindle was placed in contact with the solution, allowed to spin for 3 minutes, and the viscosity was measured in centipose.

FIG. 21 shows the relationship between the CMC / PEO ratio, PEO molecular weight, and 35% Fe ³⁺ ion-binding gel without autoclave. The top 3 curves represent data obtained on gels made of PEO with a total solids content of 2.5% and with different molecular weights as indicated. Lower curves represent data obtained on gels with a total solids content of 1.5%.

The viscosity of the gel ranged from about 10,000 to about 510,000 centipoise (cps). Increasing the CMC ratio up to about 97 increased the viscosity of each type of gel formulation studied. For gels with a 2.5% solids content, the effect of crosslinking on viscosity was greater than the effect on gels with 1.5% solids content. However, it was observed that increasing the CMC content to 100% resulted in a reduction of all types of gel viscosity studied. The maximum viscosity achieved in each type gel is achieved at a relatively low PEO weight content such as about 97% by weight (or 88% in mole fraction). However, as the PEO was removed from the gel composition, the viscosity unexpectedly decreased. Thus, it was found that by adding PEO to the gel mixture, the viscosity of the gel was increased to values above those predicted in the prior art for CMC with ions or PEO with ions.

FIG. 22 is a graph showing the relationship between% CMC and gel viscosity expressed as weight ratio of the total solids content of a series of unclaved 35% Fe ⁺³ ion-binding gels with different total solids content. The viscosity ranged from about 2,000 to 350,000 cps or more. As in FIG. 21, increasing the relative ratio of CMC to PEO in the gel increased the viscosity. In general, for all compositions of the cell studied, increasing the solids content increased the viscosity. The viscosity of the gel with the maximum CMC ratio was the maximum. However, as observed in FIG. 21, the viscosity of the gel of each solid composition unexpectedly decreases when the relative ratio of CMC to PEO is greater than or equal to 97% CMC. As in FIG. 21, the maximum viscosity of each gel composition was observed when the PRO content was 2.5% of the total solids content.

FIG. 23 shows calculated% ionic bond, 0.82 substitution degree and 97% CMC and 3 ions with 3% 8 kd PEO, iron (Fe ³⁺ ), aluminum (Al ³ ) of autoclaved gel with 2% total solids. ⁺ ) Or a graph showing the relationship between measured viscosities of ion-bound ^{cells with} calcium (Ca ²⁺ ).

For each ion used, a relatively wide range of viscosity increase was observed. In the absence of cations, the measured viscosity baseline was about 1,800 cps. In the lower content range of ions (relatively low amounts of ionic bonds), as the proportion of ionic bonds increased, the viscosity increased until the maximum was reached. Then, the increase in the ratio of the above ionic bonds decreased the viscosity. For Al ³⁺ (A), the viscosity increased from about 1800 cps to about 55,000 cps when in the range of about 20% or less and about 80% or more of the ion bonding ratio. When the ionic bond ratio was above 20%, it increased to the maximum observed at about 180,000 cps viscosity observed at about 40%.

For Fe ³⁺ (■), the viscosity decreased to about 500 cps between about 0-20% of ionic binding value. Increasing the amount of ionic bonds above about 20% resulted in a maximum viscosity of about 90,000 cps observed at about 43-45% binding, increasing the viscosity of gels having an ionic bond value range of about 35-70% to about 60,000 cps. . Increasing the ionic bond further reduced the viscosity from about 70% to 70,000 cps. The increase in the degree of ionic bond further reduced the viscosity to about 700 cps at about 905 bonds.

For Ca ²⁺ (◆), the curve shows the change for low ionic bond percent values. A maximum viscosity of about 65,000 cps was observed at the lowest binding percentage (5%). An increase in ionic bonds results in a decrease in viscosity, with a viscosity of about 2000 cps observed at ionic bond percentages of about 20 5 or more. In view of the type of ions used, increasing the percentage of ionic bonds increased the measured viscosity to a certain value of ionic bonds. However, above the maximum, further increase in ionic bonds no longer increased the viscosity. Rather, the observed viscosity decreased as the ionic content increased above the maximum. One theory that can be explained by these observations is that at relatively low ionic content, ionic crosslinking between polymer chains increases with increasing ionic content. However, by increasing the ionic content above the value required for the production of the highest viscosity, the viscosity can be reduced by facilitating intrachain interactions instead of interchain interactions. In-chain interactions lead to the formation of hairpin loops and other arrangements of functional groups on the polymer with other groups on the same chain. By forming bonds between different parts of the same chain instead of bonds in the chain, higher ionic content can prevent interactions with neighboring polymers in each chain, resulting in an ionic content that promotes in-chain interactions This resulted in a decrease in the viscosity of the gel. Therefore, the decrease in the degree of contact with increasing ionic bond is similar to the "salting-out" effect observed for other polymers in solutions containing ions. However, other theories can also explain the observations, and the invention is not intended to be limited to any particular theory.

FIG. 24 is the calculated ionic bond% and 3 ions, iron (Fe ³⁺ ), aluminum (Al ³⁺ ) and calcium of the ionically crosslinked non-clavated gel containing 2% total solids content and 8 kd PEO It is a graph showing the relationship between the viscosity measurement of the gel with respect to (Ca ²⁺ ). Generally, gels not autoclaved have a higher viscosity measurement at each percent of ionic bonds than the autoclaved gels as shown in FIG. 23. In addition, it has a maximum viscosity at certain ionic bond percentages, such as the autoclaved gel shown in FIG. 23. In the absence of ionic bonds, the baseline of the gel viscosity was about 40,000 cps.

For Al ³⁺ (A), the viscosity maximum in the range of about 30-50% ionic bonds appeared as a broad peak of about 350,000 cps. For Fe ³⁺ (■), the viscosity was at least about 100,000 cps in the range of about 10-70% ionic bond ratios and peaks between about 150,000 cps and about 175,000 cps at about 10 5 and about 433-45% ionic bonds, respectively. It showed a viscosity. For Ca ²⁺ (◆), high viscosity in the indefinite range is observed at ionic bonds in the range of about 10-20%. However, the viscosity increased above the baseline for all ionic bonds.

Example 32 Preparation of Ion-Binding Sponges

In order to prepare an ion-bonded sponge using the gel of the present invention, a gel was prepared by the method described in Examples 28-30 above. The gel is then poured into a dish made of a heat resistant material such as, for example, polypropylene. The gel is then placed in a freeze drying apparatus and freeze dried according to methods known in the art.

Lyophilized sponges comprising ionic bond PA and PO are expandable upon exposure to aqueous solutions. As disclosed in US Pat. No. 5,906,997, a composition comprising carboxypolysaccharide and polyethylene ether is hydrated or expandable when placed over moist tissue, thereby making it tacky to the tissue. Hydration rate is related to the degree of bioadhesion and antiadhesion efficacy. It was similar to the relationship between ionically crosslinked and dried sponges and antiadhesion.

Lyophilized sponges can be used as a means of preventing adhesion formation in different parts of the body, such as in the spine, orthopedic, and abdominal surgery. In addition, the sponge may be used for hemostasis.

Example 33 Preparation of Ion-Binding Microspheres

Microspheres of ionically crosslinked gels can be made by directly extruding a gel composition comprising a polymer into a solution containing polyvalent crosslinking ions. The diameter of the globules was measured by the droplet size of the gel during extrusion. See, for example, Kondo A. In Liquid Coating Process (Orifice Process) In, incorporated herein by reference; Microcapsule Processing and Technology Van Valkerburg, JWEd., Marcel Dekker, NY, pp 59-69 (1979), discloses another method for gel droplet formation. Using small orifices, the microspheres can be made smaller in size. In addition, the microspheres can be used by freeze drying. Lyophilized microspheres, including ionically crosslinked PA and PE, can expand upon exposure to aqueous solutions. As disclosed in US Pat. No. 5,506,997, a composition comprising carboxypolysaccharide and polyethylene ether is hydrated or expandable when placed over moist tissue, thereby adhering to the tissue. Hydration rate is related to the degree of bioadhesion and antiadhesion efficacy. It was similar to the relationship between ionically crosslinked and dried microspheres and antiadhesion.

Microspheres can be used to deliver the drug to the location where the gel is directly injected. By way of example, the microspheres aerosol can be inhaled to deliver the PA / PO composition to the airway simply. In addition, in situations where it is desirable to deliver a very high viscosity gel composition through a fine needle, a suspension of microspheres may be used. Suspensions of microspheres may have a lower viscosity than the equilibrium solution of the same total composition. This is because the microspheres are separable from each other, thereby allowing fluidity in the suspension. On the other hand, homogeneous solutions of crosslinked gels having the same total composition may have ionic crosslinking throughout the solution, thereby imparting a higher viscosity to the solution than in the presence of a relatively isolated suspension of microspheres.

Using a suspension of microspheres, a relatively low viscosity suspension can be delivered via a microneedle or cannula without requiring the pressure necessary to inject a high viscosity solution through a needle or cannula of the same size at a desired location. have. In addition, a suspension of microspheres or gels may be sprayed onto the surface to provide precipitation.

Example 43 Preparation of Ion-Binding Membranes

In another embodiment of the invention, ion-binding gels as described above may be formed in the membrane prior to use. In general, dry membranes may have a longer residence time on the original than undried gels. A method of making a membrane from the casting of a solution or gel is disclosed in US Pat. No. 5,906977, incorporated herein by reference. In order to form the membrane of the present invention, any of the compositions disclosed herein can be poured onto a flat surface and dried at atmospheric pressure (about 760 Torr) or reduced atmospheric pressure.

Once prepared, the membrane can be used as an anti-adhesion barrier or can be conditioned prior to use. Membranes prepared in accordance with the present invention are preferred in preferred situations where the time for which the composition remains in the site is long.

In another embodiment of the present invention, a polyacid / polyalkylene oxide membrane may be prepared by the method disclosed in US Pat. No. 5,906,977 and may be conditioned by immersing the membrane in a solution comprising a cation or a polyvalent cation. Can be. By the choice of cation or polyvalent cation type, cation content, immersion time and other conditions, cations can penetrate the membrane surface and bind to the charge of the membrane polymer, thereby increasing the degree of bonding between polymers in the membrane. Can be increased. Thus, it is possible to form a membrane surface comprising an ion-bonded polymer. Once so formed, the membrane with the conditioning surface can increase the residence time in the body, thereby exhibiting an antiadhesion effect for a longer time than the membrane thus untreated.

Example 35 Effect of Gamma Rays on CPS / PE Membrane Components

In order to study the sterilization effect on the membrane and the solution of the material used to make the membrane of the present invention, a series of studies were conducted on the effect of sterilization on the molecular weight profile.

Way

1. Chromatographic Analysis

Molecular weight profiles were obtained under aqueous conditions for the components of the CSP / PE complex by size exclusion chromatography using polygonal light scattering ("SEC-MAIL") method. The chromatography apparatus consisted of a series of three columns. These are columns containing Ultrahydrogel 2000, Ultrahydrogel 1000 and Ultrahydrogel 250 obtained from Waters Coperation. The detection system consisted of a Dawn Wyatt experimental polygonal light scattering detector and a Model 410 reflection index (RI) detector (Waters, Inc.). Molecular weight and molecular weight distribution were measured using methods known in the art.

2. Sample manufacture

Several samples of film or casting solution were exposed to 2.5 MRad gamma rays as above. After gamma radiation, gamma-treated acids and non-gamma-treated samples were prepared to have a total solids content of 0.2% (w / v) in a fluidized bed consisting of 100 mM sodium nitrate containing 0.02% sodium azide. Samples were prepared to have neutral pH. In order to analyze the molecular weight profile of the acidic film, the film was first neutralized by adding a base, and then the degree of neutralization of the solution was titrated using dilute acid. Neutral pH conditions are preferred for component molecular weight determination without obscuring by a clear change in molecular size for hydrogen bonding between polymer components. The films were analyzed after sterilization with 2.5 MRad gamma radiation or after autoclaving at 250 ° F. for 20 minutes without the need for other sterilization. In some cases, dual samples were prepared and analyzed.

A. Preparation of Analytical Membranes:

Samples made with or without blue dye from a 77% CMC / 23% PEO membrane were prepared by cutting a 220 mg film sample (# 648-2) into small pieces. For each membrane, 110 ml of fluidized bed and 40 μl of 5 N sodium hydroxide were added and the solution was stirred at low speed using a Teflon ^™ bar. After 30 minutes, the pH was measured at 9.5. 10 μl of 1 N hydrogen chloride was added to lower the pH to 8.5, and 5 μl of 1 N hydrogen chloride was further added to lower the pH to 7.2. Then the solution was poured into a 100 ml bottle and stored in the refrigerator. 5 ml aliquots were analyzed.

B. Preparation of Analytical Casting Solutions

A casting solution of 100% CMC (batch # 980506-1) with pH 4.24 was mixed with 20.5 gm CMC, 114.8 gm dilute solution and 40 μl of 5 N sodium hydroxide in a beaker and stirred with a mixer to obtain a 1.33% (w / v) solution. Made by preparing After 7 minutes the pH was 5.46. 5 μl of 5 N sodium hydroxide was added after 20 minutes and the pH increased to 5.82 after 10 minutes. Another 5 N sodium hydroxide (10 μl) aliquot was added and the pH increased to 9.48. The basic solution was acidified by addition of 10 [mu] l of 1 N hydrogen chloride to bring the pH to 6.65 after a total of 51 minutes. 5 ml of sample were analyzed.

C. Standard Manufacturing

Samples meant “standard” include CMC, PEO, or a mixture of CMC and PEO dissolved in SEC fluid bed solution. The raw material can be irradiated in a dry state to obtain "irradiated standard".

result:

The results of the study are shown in FIGS. 25A-15C.

25A shows the results for the spun and unspun film. Gamma irradiation reduces the average molecular weight of the components for mixed CMC / PEO films, pure CMC films, and pure PEO films. However, the effect was minimal for 100% CMC film (second column on the right). Mixed films comprising PEO have been shown to reduce molecular weight for stained films (left column) and blue undyed clear films (left second column). In addition, pure PEO films (right column) were also found to reduce molecular weight, with molecular weight decreases from about 1000 kd to 26 kd. Based on the above results, on average, the PEO molecules have about 38 strand breaks.

25B shows the results of gamma-irradiation for CCM and PEO standards. Gamma-irradiation was 77% CMC, as in 100% PEO standard (right column, currently reduced to about 140 kd), unlike 100% CMC composition (center column), which shows a slightly greater than 50% reduction in average molecular weight. Decrease the average molecular weight of the / 23% PEO mixture (left column).

25C shows the results of gamma irradiation and autoclaving for gel casting solution. The blue-stained casting solution comprising 77% CMC / 23% PEO mixture (left column) was shown to reduce the average molecular weight upon gamma irradiation, whereas the molecular weight was slightly reduced by autoclaving. Similarly, autoclaving of clear 77% CMC / 23% PEO mixture (second left column), 100% CMC solution (right second column), and 100% PEO solution (right column) is related to molecular weight compared to gamma irradiation. Caused a slight decrease. The average molecular weight of the PEO solution after gamma irradiation was about 12,000.

The results show that gamma irradiation can reduce the average molecular weight of gel components, gels and membranes. However, the magnitude of the reduction is, on average, about 83 strand break / PEO polymer units. Gas chromatography confirmed no components were completely depolymerized into monomer units.

Example 36 Preparation of a Composition Using CPS and PE I Slurry

In another embodiment of the present invention, CPS and PE can be mixed with a non-dissolving liquid to form a slurry before dissolving them in an aqueous preservative. The liquid used to prepare the slurry should preferably not dissolve the components to a significant extent. Suitable liquids include alcohols and, in certain embodiments, isopropanol and the like.

To prepare the membrane using this procedure, 8.25 l (1) sterilized water was placed in a stainless steel vessel containing 10 ml of FD & C Blue # 2 Dye and the solution was slowly mixed for 5 minutes.

Then 75.25 g of CMC and 24.75 gm of PEO powder were weighed to a total of 100 gm and all of these ingredients were mixed using a snow blower in a 600 ml beaker. A slurry was then prepared by adding 300 ml isopropyl alcohol to the powder CMC and PEO while mixing to moisten the powder.

After that. The mixing rate of the water / dye solution was increased until the vortex in solution was achieved. The isopropanol / CMC / PEO slurry was then added to the water / dye solution while continuing to mix. The more the slurry is mixed, the thicker it is and the speed of the vortex mixer is controlled while maintaining at about 50-150 rpm, or 100 rpm. The thicker the solution, the more the mixer should be adjusted to maintain the desired rpm and the rpm should be maintained for 1.5 to 2.0 hours. After 2 hours of mixing, the solution became homogeneous.

Thereafter, 10 ml of concentrated hydrogen chloride was added to the mixture and stirred for another 30 to 60 minutes. The pH was adjusted to within the range of 4.1-4.3.

Example 37 Composition Preparation with Slurry of CPS and PE II

In a variation of the method disclosed in Example 36, 85.25 gm of CMC and 24.75 gm of PEO powder were weighed to a total of 110 gm and all of these dry ingredients were mixed using a snow blower. After adding the isopropanol / CMC / PEO slurry to the water / dye solution, the components were mixed at high speed for 10 minutes, and then the speed was reduced to 130-150 rpm for 2-4 hours, except that The same procedure was followed. After about 2 hours, the solution became nearly homogeneous.

Example 38: Filtration of CMC / PEO Casting Solution Before Drying of Film

In some cases, the homogeneity of the casting solution can be increased by removing undissolved components prior to drying the casting solution to the membrane.

Way:

To accomplish this, the casting solution prepared according to Examples 36 and 37 was pressurized with nitrogen (5-10 pounds per inch 2 "psy") using 30 μm pore size and 50 μm pore size filters (Millipore Corp.). Was pressed through the filter. When the suspended material on the filter showed fluidity, the pressure was increased to 20 psy. The particle size distribution and filtration effect on the kissing solution and the hydration rate (%) and biotackiness of membranes prepared from the filtered or unfiltered solution were then evaluated.

result:

The results of analyzing the particle size are shown in Table 25.

The viscosity of the casting solution was measured at 10 rpm with spindle # 3, 14,800 cps for the unfiltered solution, 14,300 cps for the solution filtered with a 30 μm filter, and 15,600 cps for the solution filtered with a 50 μm filter. Was measured. Membranes prepared as unfiltered solution were hydrated at 870%, 780% for a solution filtered through a 30 μm filter and 788 5 for a solution filtered through a 50 μm filter.

Interceed ^™ , on the other hand, did not adhere and Seprafilm ^™ required 69 gms of force to separate the film from the substrate.

Example 39: Hydration and Mass of Glycerol-Containing Films

In another embodiment of the present invention, a film comprising glycerol was prepared. Glycerol is a plasticizer, and when used in membrane preparation, plasticizers can increase the flexibility of the membrane. Increasing the flexibility can make the insertion and positioning of the membrane easier and more accurate.

In this study, a series of 77% CMC / 23% PEO films were prepared according to the method above, except that the amount of glycerol was increased and incorporated in the glycerol-containing CMC / PEO film to determine the hydration and solubility in typical PBS. Was prepared. For films with glycerol, the remaining total solid composition was the same and the CMC / PEO content decreased with increasing glycerol or inclusions. The results of this study are shown in Table 30.

The data shown in Table 27 shows that increasing the proportion of glycerol in the film reduces the degree of hydration of the film. This effect was due to the reduction of CMC and PEO ratio in the film containing more glycerol. This trend was consistent with both sterile and sterile films.

In view of the corresponding mechanism, the glycerol containing film of the present invention is advantageous. First of all, they are flexible, elastic and easy to operate. For example, glycerol-containing films can be rolled up more easily and inserted into the surgical site using instruments suitable for the films of the present invention. Organizations such as Filmsert ^™ are disclosed in the ongoing patent application Ser. No. 09 / 280,101, filed 1998, 10, 24. A detailed description of such instruments and the use of delivering the film of the invention to a surgical or wound site is hereby incorporated by reference.

Form of surgery

Many types of surgical procedures can benefit from the use of the membrane or gel according to the present invention. Gels according to the present invention are designed to be used as, but not limited to, adjuncts to prevent postoperative adhesion, which is a common cause of short and long term surgical complications. Surgical forms in which gels have proven useful are in particular the spine, nerves, tendons, cardiovascular, pelvis, orthopedic, otolaryngology and ophthalmology fields. The gel can act as a barrier to temporarily intercalate between tissues that are likely to adhere to each other after surgical trauma.

Depending on the exact formulation (PA / PO weight ratio, degree of substitution, degree of polymerization,% total solids, degree and form of ionic association, etc.), the gels according to the invention are rigid from a flowable liquid-like polymer solution. Gel) can vary in hardness. Thus, gels have specific mechanical / physical properties suitable for these applications, such as cohesiveness, viscosity, coating ability and tissue adhesion, softness / coarseness, stiffness, hardness By selecting the rigidity, and the steric exclusion of certain cell types and proteins, one can tailor the above-mentioned surgery and needs.

The following is illustrative only and is not intended to limit the invention.

Example 40 Spinal Surgery

In embodiments of the invention that can be applied to spinal surgery, it may be desirable to use a mixed gel / membrane preparation to achieve the desired antiadhesion and other effects. For example, in a procedure involving surgery to the spinal cord and the intravertebral region surrounding it, the gel composition is placed directly on the nerves in the spinal space, and then the membrane preparation is placed on the gel. It may be desirable to apply to help keep the gel in place during wound healing and recovery.

How to :

A. Animals :

Five adult New Zealand white rabbits were studied in each of the three groups. Animals were anesthetized with ketamine / xylazine and shaved to produce a sterile fashion. Penicillin (150,000 U) was injected subcutaneously as a prophylactic antibiotic and an anticholinergic agent glycopyrolate was used intravenously. An indwelling intravenous catheter was inserted into the saphenous vein and injected with 0.9% physiological saline solution to maintain the open vein and maintain proper hydration. Each animal was placed on a warmed operating table and supported to facilitate an abdominal breathing pattern. Oxygen saturation, respiratory rate and electrocardiogram were monitored during anesthesia. Isoflurane gas and oxygen were used as anesthetics.

B. Surgical Preparation

L-4 to L-6 regions were dorsal incision. Two (laminectomy) were performed with the untouched spine and soft tissue separated from the two surgical sites. This prevented leakage of blood and / or test material from one site to another. One site was used as a control. The fifth animal in each group treated both surgical sites with experimental material. Thus, a total of six treatment sites and four control sites existed for each population.

C. Post-operative Care and Evaluation of Adhesion

After vertebral resection, the gel and / or membrane preparation is placed at the surgical site, the surgical site is closed using 3-0 Vicryl suture and the skin is closed using 4-0 silk suture. Closed. Each animal was placed in a warm incubator to recover from anesthesia. When each animal awoke, it was transferred to a separate cage. Four weeks after surgery each animal was slaughtered and the presence and severity of adhesion and degree of recovery were measured using the scoring method described below. The evaluator of the efficacy of the antiadhesive material did not know which material was used in which animal.

Adhesion scoring system :

1. Location of wound healing evaluation :

(1) the incision site;

(2) subcutaneous tissue;

(3) fascia;

(4) paraspinous muscles; And

(5) bone regrowth

2. Location of scar and adhesion formation evaluation :

(1) Medium scars: just below the muscle layer and above the (laminectomy site). Attached to the end of the (chuck) resection site and to the dorsal side of the remaining laminar bone, but not extended into bone defects.

(2) deep scars: extending into the (chuck) defecation defect and into the space previously containing the ligamentum flavum and epidural fat; And

(3) Double adhesions: attachment of connective tissue between bone or deep scars in the spinal canal and the dura

3. Healing grade scale :

0 full healing

1 minimal non-healing tissue

2 moderate non-healing tissue

3 Extensive non-healing tissue

4. Scar / Adhesion Grade Scale :

None

1 min or thin

2 medium

3 thick

Each animal was graded on five sides of wound healing and three sides of scar formation. Each animal was given a total healing score and a total scar score. Rank analysis and variance analysis were calculated for each treatment group and relative control group, and the differences between treatment and control groups were also calculated. The lower the score, the smaller the difference and better prevention of adhesion.

After gross evaluation of the adhesions, one animal spine was free dissected from each experimental gel and soaked in 5% formalin for histological analysis.

D. Anti-Adhesion Gel Formulations

97.5% 0.82 ds. CMC, 2.5% PEO, 60% ionic association with Ca + ions, one commercially available anti-adhesion gel Adcon-L ™ (a dextran sulfate-containing formulation from Gliatech, Inc.), and one according to the invention Three different gel formulations were studied, each with a membrane formulation (77% CMC / 22.5% PEO, pH = 4.2).

Gel A: Prepared using 1,000 kd PEO and 2.5% total solids content. The gel had a viscosity of 158,000 cps and an osmolality of 320 mOsm / kg.

Gel B: Prepared using the same gel A as above except that the total solids content was 3%. The osmolality was 312 mOsm / kg and the viscosity was 314,000 cps.

Gel C: Prepared using the same gels A and B as above except that the PEO was 4.4 Md and the total solids content was 3%. The osmotic pressure was 326 mOsm / kg and the viscosity was 306,000 cps.

E. Results

Table 28 below shows the results of the study.

Thus, the gel according to the invention can reduce the number and severity of coalescence. Thus, the use of gels and membranes according to the invention can improve anti-adhesion compared to the effects of gels alone.

Example 41 Ocular Surgery

Ophthalmic uses include glaucoma filtering surgery. Successful glaucoma filtration surgery is characterized by the passage of an aqueous humor derived from the anterior chamber through a surgically created fistula to the subconjunctival space, resulting in a filteringbleb. Is generated. Most bleb failures are often the result of fibroblast proliferation and subconjunctival fibrosis. To prevent this fibrosis, the membrane according to the invention was post-surgically positioned under the conjunctiva of the blebs space and also the membrane was placed in the fistula.

In addition, the compositions according to the invention form scars and adhesions after cataract, refractive, glaucoma, strabismus, lacrimal and retinal procedures. Can be prevented, and intra-ocular bleeding can be prevented. Fluid and gel compositions according to the invention may also act as lubricants for insertion and / or removal of intra-stromal rings and ring segment implants. The gels and fluids according to the invention can also act as protective agents for inhibiting drying and trauma during eye surgery.

Example 42 Musculoskeletal Surgery

The use of the membranes of the present invention can enhance tendon flexor repair. In tendon repair, collagen is secreted by fibroblast units at the end of the tendon. Adhesion formation usually binds the tendon to other tissue structures, thus obstructing the gliding function necessary for smooth movement by eliminating the normal space between the tendon and the tendon sheath. To prevent adhesions formed between the tendons and the sheaths, the suture tendon ends reattached to the membrane of the present invention or the hydrogel form of the present invention are injected into the encapsulation.

Example 43 Abdominal Surgery

Post-surgical adhesions have been reported to form in up to 93% of conventional surgical open patients. Lapararotomy is essential for access to the abdomen for colon and small intestine surgery, gastric, esophageal and duodenal surgery, cholecystectomy, hernia repair and surgery of female reproductive organs. In 1992, the Center for Health Statistics reported 344,000 surgeries in the United States to dissolve peritoneal adhesions. If peritoneal adhesions anatomically distort the abdominal viscera, producing a variety of morbidity ranging from intestinal obstruction and volvulus to infertility, peritoneal adhesion is pathological. . Unfortunately, adhesion remodeling and reoccurrence of intestinal obstruction after surgical division of adhesions is very common.

To prevent do novo adhesion formation or adhesion remodeling, the membrane and / or gel according to the present invention directly covers or surrounds the surgical site separating this site from the omentum. When closed, the membrane according to the invention is placed under midline incision between the fascia and peritoneum. In open surgery, a hydrogel form according to the invention is used to coat the surgical site and the entire trocar area.

Conventional examples showing in vivo efficacy in the prevention of post-surgical adhesions and in the remodeling of adhesions in experimental animals suggest that similar uses of the membranes according to the invention will also improve the adverse effects of post-surgical adhesions in patients. Provide expectations.

The composition according to the invention can inhibit the formation of de novo adhesions and / or scars at the surgical or distatnt sites, can inhibit bleeding and / or blood clot formation, and wounds It can promote healing and can act as a sealing means around re-anastomoses of organs. By inhibiting adhesions, the compositions according to the invention can thus facilitate the reoperation of the abdomen.

Example 44 Anti-Adhesion Effect II

The purpose of this study was to test the efficacy of cross-linked CMC / PEO polymers in reducing adhesion formation in the rabbit uterine horn model on adhesion formation.

How to :

Animals : 37 female New Zealand white rabbits weighing 2.4-2.7 kg were quarantined at USC kennels for about two days prior to purchase and use from an Irish farm (Norco, CA). The rabbits were randomly selected into seven populations prior to the start of surgery. The rabbits were bred for 12 hours: and injecting the feed and water, so as to enable the lithium eyidi Libby (ad libitum) 12 hours name: To run the arm cycle.

Materials : The ion-associated (IA) CMC / PEO polymers used are listed in Table 29 below. For the composition, Intergel ™ (trademark of Ethicon Division of Johnson & Johnson, Inc.) samples were used. The suture used to close the incision of the muscle and skin was a 3-0 coated Dexon II suture (Davis and Geck, Manati, PR).

Dual Uterine Horn Model : Rabbits were anesthetized with a mixture of 55 mg / kg keramine hydrochloride and 5 mg / kg loam. Following preparations for aseptic surgery, midline laps were performed. The uterine horns were removed and traumatized by peeling the serous surface with a gauze until punctate bleeding occurred. Ischemia of both uterine horns was induced by removing the lateral blood supply. The remaining blood supply to the uterine horn was the ascending branch of the uterine-vaginal artery supply in the myometrium. At the end of the surgery, 15 ml of Gel 1-5, Intergel ™, described below, was administered to the injury site with sterile gloves or no treatment (control). After seven days, the rabbits were slaughtered and the percentage of horn areas adhered to various organs was measured. In addition, the tenacity of the coalescence was scored using the following evaluation method.

Adhesion Score Evaluation :

0 = non coalescence

1 = mild, easily cleavable coalescence

2 = moderate adhesion; Non-cleavable, organs do not tear.

3 = dense coalescence; Non-cleavable, the organ tears when removed.

In addition, each rabbit was given an overall score taking all of this data into account. The following scoring method was used:

0 non coalescence

0.5+ light, film-like coalescence associated with only one organ, usually 1 or 2 small coalescences

1.0+ light, film-like coalescence, slightly broader than 0.5, but not coalescence

1.5+ slightly coarse and broader adhesion than grade 1

2.0+ coarse adhesion, rather extensive, usually the uterine horn has adhesion to both the bowel and bladder.

Same as 2.5+ 2 except that adhesion is usually not filmlike at any site and broader.

For 3.0+ 2, more extensive and coarse adhesions with both horns attaching to the intestines and bladder, allowing for some uterine movement.

Same as 3.5+ 3, except that coalescence is somewhat more extensive and coarse.

4.0+ severe adhesions, horns attached to the intestines and bladder, unable to move the uterus without tearing the adhesions.

Rabbits were evaluated by two independent observers blinded prior to animal treatment. If there was a discrepancy with respect to the score assigned to the individual animals, higher scores were assigned.

Statistical analysis : The total scores were analyzed by rank analysis and grading variance analysis for each treatment group and relative control group, and analyzed for the difference between treatment group and control group. The lower the score, the smaller the difference and better prevention of adhesion.

Result :

The effect of the administration of the polymer on the frequency of adhesion formation can be found in Table 29 below.

Data are expressed as mean score ± standard deviation. n = 5-7 animals in each population

According to the Mann-Whitney U experiment, all gel formulations according to the invention reduced the overall score and frequency of adhesions compared to untreated animals. The highest antiadhesion effect was obtained using a gel with low molecular weight PEO (8 kd; gel 3). However, even gels with high molecular weight PEO (100 kd; gels 1-2, and gels 4-5) were effective. Administration of the gel did not combine with the presence of an inflammatory response.

Example 45 Gynecological Surgery: myomectomy via laparotomy or laparoscopy

In surgical excision of fibroids, the uterus was exposed and dissected to remove the fibroids. The uterus was closed with an absorbable suture. Later uterine incision combined with a higher degree of adnexal adhesions than the bottom or anterior uterine incision. For later incisions, the necessity of the present invention was applied above and below the abdominal wall incision to prevent adhesion formation between the uterus and surrounding tissue. A more common anterior incision resulted in an attachment between the bladder and the anterior wall of the uterus. Membranes and / or gels according to the invention were placed over the anterior incision and between the uterus and the bladder.

Example 46 Thoracic Surgery

In some forms of thoracic surgery procedures, the compositions of the present invention may work beneficially. The composition can inhibit scar and adhesion formation around the heart, lungs, respiratory tract, and esophagus, thus facilitating re-surgery. The composition can inhibit bleeding, promote wound healing, and act as a seal around arterial puncture, blocking and around reanastomoses of blood vessels and organs. The membrane can also be used as a temporary pericardium. In addition, the compositions according to the invention can also lubricate surgical instruments, including but not limited to endoscopy tools and endovascular tools, conduits, stents and devices.

Re-operation Cardiac surgery is becoming more common, resulting in the need to reduce or prevent mediastinal and pericardial adhesions after surgery. Median sternotomy precedes median pericardiatomy. The pericardium was suspended, thus exposing the heart and pericardial spaces widely. An incision was performed. For vascular bypass, distal anastomoses were constructed using an internal mammary artery, radial artery, or gastroepiploic artery or saphenous vein graft. In order to prevent adhesion formation, a membrane according to the present invention was placed between the pericardial and sternum before surrounding and closing the anastomosis.

Example 47 urological procedure

Gels and fluids according to the present invention can be used in a variety of urological operations involving the introduction of instruments and devices, such as catheters into the urethra, bladder, and ureters, thus inhibiting trauma that may expose tissues during surgery. Can be. Injection of fluids and / or gels into the urinary tract can act as a lubricant to promote removal of gallstones and stones. Fluids and / or gels may also improve visualization of the structure during surgery and inhibit bleeding and clot formation.

Example 48 Plastic Surgery

In plastic surgery, the compositions according to the invention are used to coat the exterior of various types of implants, including penile or breast implants and thus inhibit the formation of scars, adhesions, It can interfere with capsular contracture, resulting in implantation of prosthesis. The compositions according to the invention can also be used as filler materials for breast inserts or testicular inserts or as artificial sphincter.

Example 49: Orthopedic and Joint Procedure

The composition according to the invention can be used to inhibit the formation of scars and adhesions due to the following joint replacement surgery, joint correction and tendon surgery. The gels and fluids according to the invention can be used as lubricant substitutes for joints, thus reducing the swelling of joint structures combined with pain, inflammation and osteoarthritis. The gels and fluids according to the invention can also be used as tendons and ligament lubricants, thus reducing the frequency of inflammation of the tendons, ligaments and sheaths. The composition can act as a resorbable tissue growth scaffold or construct to replace missing or weak tissue with regrown tissue.

Example 50 Treatment of Joint Inflammation

In another embodiment, the indication of joint inflammation can be reduced by delivering the gel composition directly into the joint. An arthroscope may be used to visualize the area where the gel will be deposited, or delivered into the joint via a needle. In some situations, it may be desirable to inject microspheres instead of homogeneous gels.

Example 51 Ear, Nose and Throat Procedures

The composition according to the invention is used to inhibit the scars and adhesions resulting from the following nose, nare, sinus, middle ear and inner ear surgery.

Example 52 Drug Delivery

The composition according to the invention is used for local administration of drugs, growth factors, enzymes, proteins, pharmacological agents, genes, gene fragments, vitamins, and naturopathic substances. The compositions are used in dosage forms intended for oral ingestion, inhalation, transdermal application, rectal application, vaginal application, and ocular administration. Lose. The composition according to the invention can be mixed in combination with a surface coating, deposition, impregnation, encapsulation, or a monolayer or multilayer embodiment.

Drug forms include antibacterial agents, antiinflammatory agents, antiparasitics, antivirals, anesthetics, antifungals, analgesics, diagnostics, antidepressants ), Decongestants, antiarthritics, antiasthmatics, anticoagulants, anticonvulsants, antidiabetics, antihypertensives, antiadhesion agents, anticancer agents, gene replacement or modification agents, and tissue replacement drugs.

Other features, aspects, and objects according to the invention may be obtained through a review of the drawings and claims. All citations herein are hereby incorporated by reference in their entirety.

Other embodiments according to the present invention are developed within the spirit and scope of the present invention and claims and it is obvious.

Claims (95)

Polyacid (PA); Polyalkylene oxides (PO); And An ionically crosslinked gel comprising a polyvalent cation. The method of claim 1, wherein the polyacid is carboxypolysaccharide, polyacrylic acid, polyamino acid, polylactic acid, polyglycolic acid, polymethacrylic acid, polyterephthalic acid, polyhydroxybutyric acid, polyphosphoric acid, polystyrenesulfonic acid and the multiplex Gel selected from copolymers of acids. 3. The polyacid according to claim 1 or 2, wherein the polyacid is carboxymethyl cellulose (CMC), carboxyethyl cellulose, chitin, carboxymethyl chitin, hyaluronic acid, alginate, propylene glycol alginate, pectin, carboxymethyl dextran, carboxymethyl A gel that is a carboxypolysaccharide selected from chitosan, heparin, heparin sulfate, chondroitin sulfate and polyuronic acid, including polymannuronic acid, polyglucuronic acid and polygluronic acid. The gel of claim 1 wherein the polyacid is carboxymethylcellulose. The gel of claim 1 wherein the polyacid is carboxyketylcellulose having a molecular weight ranging from about 10 Kd to about 10,000 Kd and a degree of substitution ranging from about 0 to about 3 or more. 6. The gel according to claim 1, wherein said polyalkylene oxide is selected from polypropylene oxide, polyethylene glycol, polyethylene oxide and PEO / PPO block copolymers. The gel of claim 1 wherein the polyalkylene oxide is polyethylene glycol or polyethylene oxide having a molecular weight in the range of about 200 d to 8000 Kd. The gel of claim 1 wherein the polyalkylene oxide is polyethylene glycol having a molecular weight in the range of about 200 d to 5 Kd. The gel of claim 1 wherein the PA ranges from about 10% to about 99% by weight of the total solids content. The gel of claim 1, wherein the PA ranges from about 50 to about 99 weight percent of total solids content. The gel of claim 1 wherein the PA ranges from about 90 to about 99 weight percent of the total solids content. The gel of claim 1 wherein the PO ranges from about 1 to about 90 weight percent of the total solids content. The gel of claim 1, wherein the PO ranges from about 1 to about 10 weight percent of the total solids content. The gel of claim 1 wherein the PO is about 2.5% by weight of the total solids content. The gel of claim 1 wherein the gel has a total solids content of about 1-10%. The gel according to any one of claims 1 to 15, wherein the cation is a trivalent cation. The gel of claim 1 wherein the cation is selected from Fe ⁺³ , Al ⁺³ , and Cr ⁺³ . 16. The gel according to any one of claims 1 to 15, wherein the cation is a divalent cation. The gel of claim 1 wherein the cation is a divalent ion selected from Ca ⁺² , Zn ⁺² , Mg ⁺² and MN + ² . 20. The gel according to any one of claims 1 to 19, wherein the cation is accompanied by an inorganic anion. The method according to any one of claims 1 to 19 wherein the cation is _{^{Cl, PO 4 2-, HPO 3}} -, CO 3 2-, HCO 3 -, accompanied by an inorganic anion selected from SO ₄ ^2-, and borate Gel. 20. The gel according to any one of claims 1 to 19, wherein the cation is accompanied by an organic anion. 20. The gel according to any one of claims 1 to 19, wherein the cation is accompanied by an organic anion selected from citrate, oxalate and acetate. The gel of claim 1, wherein the gel has a pH in the range of about 2.0 to 7.5. 24. The gel of claim 1 wherein the gel has a pH in the range of about 2.5 to 6.0. 26. The gel according to any one of claims 1 to 25 further comprising a medicament. 26. The gel according to any one of claims 1 to 25, further comprising an agent selected from antithrombogen agents, anti-inflammatory agents, hormones, chemotactic factors, analgesics, growth factors, cytokines, osteogenic factors and anesthetics. 26. The method according to any one of claims 1 to 25, further comprising an agent selected from heparin, tissue plasminogen activator, aspirin, ibuprofen, ketoprofen, proteins and peptides including RGD motifs, and nonsteroidal anti-inflammatory agents. Gel. 29. The gel of claim 1 having a viscosity of about 500,000 centipoise or less. (a) selecting a polyacid; (b) selecting a polyalkylene oxide; (c) forming a solution of the polyacid and the polyalkylene oxide; And 30. A method for preparing an ion binding gel according to any one of claims 1 to 29, comprising adding a cation to the solution. (a) selecting a polyacid; (b) selecting a polyalkylene oxide; (c) mixing the polyacid and the polyalkylene oxide to form a dry mixture of the polyacid and the polyalkylene oxide; (d) dissolving the mixture of polyacid and polyalkylene oxide to form an aqueous solution of polyacid and polyalkylene oxide; And (e) adding an aqueous solution comprising a cation to an aqueous solution of the polyacid and polyalkylene oxide, such that the polyacid, polyalkylene oxide and cation form an ionic bond. A method for preparing an ion binding gel according to any one of claims 29. 32. The polyacid according to claim 30 or 31, wherein the polyacid is carboxypolysaccharide, polyacrylic acid, polyamino acid, polylactic acid, polyglycolic acid, polymethacrylic acid, polyterephthalic acid, polyhydroxybutyric acid, polyphosphoric acid, polystyrene And a copolymer of sulfonic acid and said polyacid. 32. The polyacid according to claim 30 or 31, wherein the polyacid is carboxymethyl cellulose (CMC), carboxyethyl cellulose, chitin, carboxymethyl chitin, hyaluronic acid, alginate, pectin, carboxymethyl dextran, carboxymethyl chitosan, heparin, heparin And carboxypolysaccharides selected from sulfates, chondroitin sulfates and polyuronic acids, including polymannuronic acid, polyglucuronic acid and polygluronic acid. 32. The method of claim 30 or 31, wherein the polyalkylene oxide is selected from polypropylene oxide, polyethylene glycol, polyethylene oxide and copolymers of the polyalkylene oxide. 32. The method of claim 30 or 31, wherein the cation is selected from trivalent and divalent cations. 32. The method of claim 30 or 31 wherein the cation is selected from Fe ^{+ 3} , Al ⁺³ and Cr ⁺³ , Ca ⁺² , Zn ⁺² , Mg ⁺² and MN + ² . 32. The method of claim 30 or 31, further comprising adjusting the pH to a range of about 3.5 to 7.5. 32. The method of claim 30 or 31, further comprising disinfecting the gel. 32. The method of claim 30 or 31, further comprising disinfecting the gel using a method exposed to autoclave or ethylene oxide. A method of alleviating postoperative adhesions comprising applying the composition of claim 1 to contact with tissue forming adhesions with adjacent tissues in the absence of the gel. (a) accessing a surgical site; (b) performing a surgical procedure; And (c) applying the composition according to claim 1 in contact with a tissue that forms an adhesion with adjacent tissue in the absence of the gel. 42. The method of claim 40 or 41, wherein the surgical procedure is performed on the abdomen, eyes, orthopedic, stomach, thoracic, cranial, cardiovascular, gynecological, urinary, plastic, musculoskeletal, spinal cord, nerve, tendon ( tendon), otolaryngology and pelvic surgical procedures. 42. The surgical procedure according to claim 40 or 41, wherein the surgical procedure includes appendectomy, cholecystectomy, hernia repair, peritoneal detachment surgery, kidney surgery, bladder surgery, urethral surgery, prostate surgery, salingostomy, fallopian tube surgery. (salpingolysis), hysterectomy, endometrial hyperplasia, ectopic pregnancy treatment, uterine myomectomy, myoma of the uterus, hysterectomy, hysterectomy, intervertebral discectomy, tendon surgery, spinal fusion, arthroplasty, arthroplasty, Choice of Strabismus Surgery, Knock-in Filtering, Tear Drainage, Sinus Surgery, Ear Surgery, Bypass Anastomosis, Heart Valve Replacement, Thoracotomy, Synovial Resection, Cartilage Plastic Surgery, Loose Body Resection, and Scar Tissue Resection How to. A method of treating arthritis symptoms comprising delivering a composition according to claim 1 to arthritis. The method of claim 44, (a) accessing a site of arthritis; And (b) further comprising sealing said site. 45. The method of claim 44, wherein said approaching step is performed using an arthroscope. 30. A method for alleviating post-traumatic adhesions comprising delivering a composition according to claim 1 to a traumatic site. 48. The method of claim 47, further comprising accessing the traumatic site prior to said delivery step. (a) ablation of the adhesion to separate previously adherent tissue; And (b) applying a composition according to any one of claims 1 to 29 between previously adherent tissues. 45. The method of claim 44, further comprising accessing the coalescing site prior to the ablation step. 30. A method of alleviating surgical trauma induced by a surgical tool, comprising coating the surgical tool with a composition according to any one of the preceding claims prior to use of the surgical tool. 30. A method of reducing friction between adjacent tissues, comprising applying the composition according to any one of claims 1 to 29 to adjacent tissues. 30. A method of coating a catheter and probe, comprising contacting the catheter or probe with a composition according to any one of the preceding claims. 30. A dry membrane comprising the composition according to claim 1. 30. The ionically crosslinked gel according to any one of claims 1 to 29 wherein the retention time is increased by increasing the viscosity of the gel. (a) dipping the polyacid polyalkylene oxide membrane in a solution comprising a cation or multiple cations; And (b) A method of conditioning a membrane according to claim 54 comprising the step of redrying the membrane. It comprises a binding complex of carboxypolysaccharide (CPS) and polyether (PE) and has at least one of bioabsorbability, bioadhesion, antithrombogen and antiadhesion, and has a pH in the range of about 2.5 to 4.5 A dry composition having at least about 100% hydration. 58. The composition of claim 57 wherein said CPS is carboxymethyl cellulose (CMC), carboxyethyl cellulose, chitin, carboxymethyl chitin, hyaluronic acid, alginate, propylene glycol alginate, carboxymethyl chitosan, pectin, carboxymethyl dextran, heparin, A composition selected from heparin sulfate, chondroitin sulfate and polyuronic acid, including polymannuronic acid, polyglucuronic acid and polygluronic acid. The composition of claim 57 or 58 wherein the molecular weight of the CPS is between 100 and 10,000 Kd. 60. The composition of any of claims 57-59, wherein the molecular weight of PE is between about 4 and 8000 Kd. 61. The composition of any of claims 57-60, wherein the CPS is CMC. 61. The composition of any of claims 57 to 60, wherein the PE is polyethylene oxide (PEO). 63. The composition of any of claims 57-62, wherein the proportion of total solids content of CPS is 10-95% by weight and the proportion of PE is 5-90% by weight. 64. The composition of any one of claims 57-63, wherein the degree of substitution of CPS is at least about 0 and up to a range comprising about 3. 65. The composition of any one of claims 57 to 64, further comprising a medicament. 66. The composition of claim 65, wherein the medicament is selected from antibiotics, anti-inflammatory agents, hormones, chemotactic factors, peptides and proteins including RGD motifs, analgesics and anesthetics. 67. The composition of any one of claims 57 to 66, further comprising multiple membranes of CPS and PE. 68. The CPS molecular weight according to any one of claims 57 to 67, having at least one property of bioadhesiveness, absorbency or flexibility, wherein the property comprises (1) a CPS molecular weight in the range of about 100 to 10,000 Kd, (2) about 5 to PE molecular weight in the range of 8000 Kd, (3) CPS substitution degree ranging from about 0 or more and up to about 3, (4) CPS ratio of about 10 to 95% by weight in the ratio of CPS and PE, and about A composition controlled by at least one of a PE ratio in the range of 5 to 90% by weight, (5) a membrane pH of between about 2.5 and 4.5 or less. 69. The composition of any one of claims 57 to 68 further comprising a plasticizer. 70. The method of claim 69, wherein the plasticizer is glycerol ethanolamine, ethylene glycol, 1,2,6-hexaneethriol, monoacetin, diacetin, 1,5-pentanediol, PEG, propylene glycol and trimethylol Composition selected from propane. 71. The composition of claim 69 or 70, wherein the amount of plasticizer added is about 0-30 wt% or more. 71. The composition of claim 70, wherein the plasticizer is glycerol in an amount of about 2-30 wt%. 73. The composition of any of claims 57-72, wherein the ratio of carbon atoms to oxygen atoms on the surface is between about 2-4. 74. The composition of any of claims 57 to 73, wherein the PEO is on the surface of the composition. 75. The composition of any of claims 57-74, wherein the C1s coating comprises at least about 20-100% C-O bonds. 75. The composition of any of claims 57-74, wherein the C1s coating comprises at least about 25-100% C-O bonds. 77. The composition of any of claims 57-76, wherein the C1s coating comprises about 42% C-O bonds. 78. The composition of any of claims 57-77, wherein the O1s coating comprises at least about 73-100% O-C bonds. 78. The composition of any one of claims 57-77, wherein the O1s coating comprises at least about 82-100% O-C bonds. 80. The composition of any one of claims 57 to 79 wherein the adhesion of platelets to the surface of the composition is 0 platelets / 25,000 μm ² to 65 platelets / 25,000 μm ² . 80. The composition of any one of claims 57 to 79 wherein the adhesion of platelets to the surface of the composition is 0 platelets / 25,000 μm ² to 25 platelets / 25,000 μm ² . 80. The composition of any one of claims 57 to 79 wherein the adhesion of platelets to the surface of the composition is 0 platelets / 25,000 μm ² to 3 platelets / 25,000 μm ² . 83. The composition of any one of claims 57-82, wherein the time of remineralization of plasma is between about 6-18 minutes. 83. The composition of any one of claims 57-82, wherein the remineralization time of plasma is between about 13 and 18 minutes. 83. The composition of any of claims 57-82, wherein the time of remineralization of plasma is about 15 minutes. (a) preparing an aqueous solution of CPS having a molecular weight of about 100 to 10,000 kd and a degree of substitution of about 0 to 3.0; (b) preparing an aqueous solution of PE having a molecular weight of about 5 to 8000 kd; (c) mixing the CPS solution and the PE solution to form a mixed solution of the CPS and the PE, wherein the ratio of the CPS and the PE is about 1: 9 to about 19: 1; (d) adjusting the pH of the mixed solution to a range between about 2.5 and 4.5; And (e) drying the composition. 87. The method of claim 86, wherein said CPS is CMC. 88. The method of claim 86 or 87, further comprising increasing the pH of the dried composition. 88. The method of claim 86 or 87, wherein the pH of the composition is increased to about 6.0. 90. The method of claim 86 or 89, wherein increasing the pH comprises using a phosphate buffer, a phosphate buffer salt. (a) accessing a surgical site; And (b) delivering the composition according to any one of claims 1 to 29 to said site. 92. The method of claim 91, wherein the surgical procedure is orthopedic, eye, stomach, abdomen, chest, cranial, otolaryngology, cardiovascular, obstetrics, arthroscopic endoscopy, urology, skin, subcutaneous, plastic and musculoskeletal. How to choose from surgical procedures. 93. The method of claim 91 or 92, further comprising applying a dry composition of CPS and PE onto the gel. 30. The gel according to any one of claims 1 to 29, wherein said polyvalent cation is a multication selected from polyamino acids, chitosans, basic proteins and basic peptides including polylysine and polyarginine. 31. The method of claim 30, wherein said polyvalent cation is a multication selected from polyamino acids, chitosans, basic proteins, and basic peptides including polylysine and polyarginine.