RU2627666C1 - Method for getting surgical barrier material based on polysaccharides - Google Patents

Abstract

FIELD: biotechnology.

SUBSTANCE: to get the barrier material using apple pectin and chitosan, the last preferably with 38-100% deacetylation degree and molecular weight 25-230 kDa. According to the method, apple pectin is dissolved in water, calcium chloride or chitosan with addition of calcium chloride is dissolved in 0.25% aqueous solution of acetic acid, the resulting solution is frozen at minus 18±1°C, then layer the apple pectin solution to it. Mass ratio of pectin and chitosan is 3:1. The frozen solution is slowly thawed for 4-6 hours at a temperature of 15-22°C. The formed surgical barrier material is freeze-dried and then sterilized by UV irradiation.

EFFECT: surgical barrier material in the form of cryogel has biocompatible properties, a period of biodegradation not exceeding 24 hours, and allows effective prevention of adhesions formation in the experiment.

2 cl, 1 dwg, 2 tbl, 5 ex

Description

The invention relates to biopolymers and can be used in medicine (surgery) for the prevention of connective tissue adhesions that occur after abdominal operations and inflammatory processes in body cavities.

The primary field of use of the invention is abdominal surgery, gynecology.

A known method of manufacturing biodegradable membranes to prevent the formation of adhesions after cardiac surgery, which describes a membrane based on a copolymer of polyhydroxybutyrate / hydroxyvalerate (PHBV) and poly (D, L-lactide). A membrane is made by the method of electrostatic formation (electrospinning), during which biologically active substances from the group of fibrinolytic drugs or drugs from the group of direct anticoagulants are included in the fiber structure. The membranes have biocompatible properties, a biodegradation period not exceeding 60 days, and can effectively prevent the formation of adhesions in the experiment (see RF Patent 2525181).

The disadvantage of this barrier material is the need for the introduction of additional components for the manifestation of anti-adhesion activity, as well as too long a foreign body is present in the body. To prevent adhesion formation, a period of 5 to 10 days is sufficient [1]. In addition, in the process of biodegradation of the material, toxic products can form that have a negative effect on the body.

Shredded polymer hydrogels are known to exclude the formation of adhesions and methods for their preparation (see RF Patent 2207882). Molecularly crosslinked gels are described which contain a variety of biological and non-biological polymers, for example, proteins, polysaccharides and synthetic polymers. The use of such gels in a living body (in vivo) is useful for preventing the formation of postoperative spinal and other tissue adhesions, for filling tissue defects, body cavities, surgical defects, etc.

The disadvantage of these hydrogels is that they use toxic crosslinking agents: aldehydes, epoxides, succinimides, carbodiimides, maleimides, azides, carbonates, isocyanates, divinylsulfone, alcohols, amines, imidates, anhydrides, halogens, silanes, diazoacetates, aziroacetate, aziride .P. The reagents mentioned are highly toxic, their use is accompanied by the formation of by-products, the complete removal of their excess from the reaction mass is almost impossible.

An invention is known that describes surgical barriers with adhesion-inhibiting properties (see RF Patent 2480246), which include a wound-facing polymer coating containing an enteric polymer; and at least one flexible carrier, wherein said at least one flexible carrier has at least one outer surface, said polymer coating being applied to said at least one flexible carrier so as to substantially coat said at least one outer surface of the carrier.

The disadvantage of surgical barriers is that they consist of various cellulose derivatives, the production of which by chemical modification is a time-consuming and expensive process.

The invention is known - biomaterial for the prevention of postoperative adhesions, including derivatives of hyaluronic acid (options) and a method for preventing postoperative adhesions of the tissue (see RF Patent 2177332), can be used in the field of surgery, in particular for use in the prevention of postoperative adhesions in surgery. This invention relates to new biological products, an integral part of which are esterified derivatives of hyaluronic acid or cross-linked derivatives of hyaluronic acid.

The disadvantage of the invention is that to obtain derivatives of hyaluronic acid, it is necessary to use toxic organic solvents, which can adversely affect the biocompatibility of the obtained barrier materials.

A known method for the prevention of adhesions and their relapse (see RF Patent 2331367), based on the separation of damaged serous membranes and their mesothelization by introducing into the wound area 5% pectin gel. The method allows to prevent the bonding of surfaces for the period of their mesothelization. The disadvantage of this method is the use of a pectin solution that does not have wound healing activity.

Known multilayer anti-adhesive barrier membrane (see Republic of Korea Patent KR 20100013837), which prevents adhesion formation, providing protection and separation of wound surfaces from tissues and organs. The multi-membrane structure consists of a tissue adhesive layer containing collagen, gelatin, elastin, chitin or chitosan, and a lubricant layer containing alginic acid, pectin, carrageenan, gellan gum, carboxymethyl cellulose, hyaluronic acid or dextran polysaccharide. The adhesive layer is crosslinked with the lubricating layer using glutaraldehyde, formalin, N- (3-dimethylamidopropyl) -N'-ethylcarbodiimide or N-hydroxysulfosuccinimide sodium salt.

A significant disadvantage of this invention is the use to obtain a multilayer structure of toxic crosslinking agents.

The closest analogue is a method for producing a gel based on pectin from the aerial part of narrow-leaved fireweed (see RF Patent 2510275). The claimed method includes dissolving pre-isolated pectin from the aerial part of narrow-leaved fireweed in water, followed by cooling and applying it to a frozen solution of chitosan and the subsequent formation of a gel. The method allows to obtain a degradable biomaterial with antimicrobial activity against cells of Escherichia coli and Staphylococcus aureus.

The disadvantage of this method is the use of pectin from the aerial part of the fireweed narrow-leaved, not having anti-adhesion activity, as well as chitosan with an unknown molecular weight and degree of deacetylation.

The problem solved by the present invention is to obtain a surgical barrier material based on biocompatible, biodegradable polysaccharides - apple pectin or apple pectin and chitosan without the use of toxic crosslinking reagents for use in order to prevent postoperative adhesions in the abdominal cavity.

Surgical barrier materials according to the invention include polysaccharides apple pectin or apple pectin and chitosan.

The technical result is achieved due to the fact that when using a surgical barrier material obtained by freezing and subsequent thawing of initial solutions of apple pectin or apple pectin and chitosan (with a degree of deacetylation of 38-100% and a molecular weight of 25-230 kDa) with calcium chloride, according to the proposed method, the formation of postoperative adhesions in the abdominal cavity is prevented.

To obtain a surgical barrier material, calcium chloride or chitosan and calcium chloride are dissolved in a 0.25% aqueous solution of acetic acid with stirring. The resulting solution is poured into a mold and frozen at a temperature of -18 ± 1 ° C for 1 h. Apple pectin is dissolved in distilled water with stirring. Then, apple pectin solution is layered on a frozen solution of calcium chloride or chitosan and calcium chloride, while the mass ratio of pectin and chitosan in the composition of the surgical barrier material is 3: 1. The surgical barrier material is formed by slowly thawing a solution of calcium chloride or chitosan and calcium chloride at a temperature of 15 ° C-22 ° C for 4-6 hours. The formed surgical barrier material is freeze-dried and then sterilized by UV radiation for 0.5 h each side. The resulting surgical barrier material is in the form of freeze-dried cryogel.

Adhesions are thin fibrin strands, films, and adhesions that occur between adjacent organs. The causes of adhesions are extremely diverse. Among them, mechanical and physical damage to the serous integument of the intestine, the ingress of foreign material into the abdominal cavity, ischemia of the abdominal organs due to impaired blood flow, infectious inflammation of the peritoneum, and intraperitoneal bleeding can be distinguished [2].

All these factors are present when performing surgical operations, so the first place among the immediate causes of the development of adhesions is the surgery itself. Intraperitoneal adhesions occur in more than 90% of patients who have previously undergone abdominal surgery [3]. In most cases, they are caused by trauma, in 22.5% of patients - by foreign bodies, suture material - 19%; talc - 6%, in combination - 3%. Other causes are inflammatory diseases within the abdominal cavity and congenital abnormalities [4].

Adhesion can cause intestinal obstruction, pelvic pain, subsequent infertility and ectopic pregnancy in women [5]. Prevention of the formation of adhesions and inflammatory diseases of the abdominal cavity is an urgent problem of abdominal surgery.

The pathophysiological mechanism is still unclear, but a common central pathway has been proven in which peritoneal fibrinolysis plays an important role.

Intraperitoneal adhesions form when the damaged areas of the peritoneum are firmly in contact. Damage to the peritoneum initiates the release of histamine and kinins by stromal mast cells, which increase vascular permeability. An exudate is formed containing fibrin, which is deposited between damaged serous surfaces. These membranous fibrinous adhesions are unstable and degrade under the action of proteases of the fibrinolytic system for 72 hours. The healing process is characterized by a combination of fibrosis and mesothelial regeneration. If fibrinolytic activity is low and fibrin is not rapidly removed by absorption or fibrinolysis, then fibroblasts, mesothelial and endothelial cells migrate into it, collagen accumulates, blood vessels sprout and strong fibrinous adhesions form by the end of 1 week. Thus, the tight fit of damaged serous surfaces and the imbalance between the formation of fibrinous deposits and fibrinolysis are the key points in the formation of adhesions [6].

There are various methods for preventing adhesion formation, but all of them are based on several approaches, which include stimulation of fibrinolysis, reduction of the primary inflammatory process, mechanical separation of surfaces coated with fibrin, inhibition of the blood coagulation system, and suppression of fibroblast proliferation [2].

Based on these approaches, in recent years, various means of preventing adhesions in the abdominal cavity have been actively developed and introduced into clinical practice. They can be divided into pharmaceuticals (steroidal and non-steroidal anti-inflammatory agents, anticoagulants, proteolytic agents) and barrier materials (polymer solutions, solid sheets, hydrogels).

Most pharmaceutical preparations were not effective enough when used as anti-adhesive agents [4, 7]. The ineffectiveness of the use of pharmaceuticals may be associated with their rapid removal from the abdominal cavity, as they are most often used in the form of solutions.

The current trend in the prevention of postoperative adhesions is the use of tools that limit the wound surface from surrounding tissues for a period sufficient to restore mesothelium.

The most promising method for preventing the formation of postoperative adhesions is considered to be the use of barrier methods from biodegradable materials. Available barrier materials are solid, gel or liquid agents. Many of them liquefy in the body after some time. Biocompatible, absorbable gel barriers are safe and effective; moreover, they are easy to apply and quickly adapt to damaged tissues without fixation. The use of barriers differs from other methods in that they themselves do not affect the healing process, but share opposite surfaces during healing. Barrier products are placed inside the peritoneum during or at the end of the operation. Barrier materials based on oxidized regenerated cellulose ("Interceed") and on the basis of stretched polytetrafluoroethylene (e-PTFE) - "Gore-Tech" (see US Patent No. 4478665 and US Patent No. 44482516) or polyethylene are currently approved for clinical use. , or polypropylene.

It should be noted that both of the above materials are associated with important contraindications. The use of e-PTFE or polyethylene or polypropylene barrier membranes involves the implantation of a synthetic material that is foreign to the human body and is not capable of biodegradation, and which requires repeated surgery to remove the barrier membrane.

In preclinical and clinical models, oxidized regenerated cellulose nets were found to be effective in preventing adhesion formation, but only if complete hemostasis preceded them.

In this invention, the basis of the resulting surgical barrier materials is low methyl esterified apple pectin, which is capable of gelation in the presence of divalent Ca ^{2+ ions} . In the process of obtaining surgical barrier materials, apple pectin is layered on the surface of a frozen solution of chitosan with calcium chloride. When the solution of chitosan with calcium chloride is slowly thawed, a polyelectrolyte complex is formed between oppositely charged macromolecules of apple and chitosan pectin. An electrostatic interaction occurs between the amino groups of chitosan (NH ³⁺ ) and the carboxy groups of apple pectin (СОO ^- ). Calcium ions diffuse into the layer of apple pectin and bind the remaining free carboxyl groups, which are present in excess, since apple pectin is the main component of surgical barrier materials. Thus, the surgical barrier material is formed during the ionic interaction of oppositely charged polysaccharides and additionally crosslinked by Ca ^{2+ ions} , without the use of toxic crosslinking reagents, the use of which is accompanied by the formation of by-products, the complete removal of their excess from the reaction mass is practically impossible.

Apple pectin is a natural anionic polysaccharide, the main component of the cell wall of plants. The main carbohydrate chain of pectin is made up of 1,4 - linked residues of α - D - galacturonic acid, which can be partially replaced by methyl ether residues (up to 70%). Depending on the degree of methyl esterification (SM), pectins are divided into highly methyl esterified, in which SM> 50%, and low methyl ether, with SM <50%. Typically, highly methylated pectins form gels in the presence of soluble solids, such as sugars, while low methylated pectins are capable of gelation in the presence of divalent cations, such as Ca ²⁺ [8]. Pectins themselves are composed of molecules with anti-inflammatory activity, therefore materials based on them suppress inflammation without introducing any additional pharmacological agents [9].

To give surgical barrier materials greater adhesion, strength, wound healing and antioxidant activity, chitosan, a cationic polysaccharide, a deacetylated derivative of the natural chitin polysaccharide, which is the main component of the outer integument of arthropods, some fungi, is included in the composition of the anti-adhesive agent. Chitosan consists of residues of D-glucosamine and N-acetyl-D-glucosamine units connected by β-1,4-glycosidic bonds. One of the most important properties of a polymer is its degree of deacetylation (DM), which determines whether the biopolymer is chitin or chitosan. With diabetes> 40%, the biopolymer is chitosan. DM affects the physical, chemical, and biological properties of chitosan [10]. To obtain chitosan samples that differ in diabetes, reacetylation [11] and deacetylation [12] methods can be used. An equally important characteristic of a polymer is molecular weight (MM). MM affects the rate of biodegradation, adhesiveness, antioxidant properties of the polymer. Based on high molecular weight chitosan, samples with lower molecular mass can be obtained by chemical, physical, and enzymatic depolymerization [13]. Thus, by varying the MM and DM of chitosan, it is possible to obtain material with the characteristics necessary for a specific purpose. Chitosan also promotes wound healing and restoration of mesothelial cells [14].

In addition, pectins and chitosans have antioxidant activity [15, 16]. Since inflammation and oxidative stress mediate the formation of adhesions, pectin - chitosan barrier materials will have anti-adhesion effectiveness.

Surgical barrier materials have clear advantages over the liquid form of anti-adhesive materials, since liquid materials are eliminated too quickly. However, the gel barrier materials used today do not show sufficient effectiveness to prevent abdominal adhesions in humans, because their effect is limited by the function of the physical barrier.

In this case, the invention describes surgical barrier materials based on biocompatible, biodegradable polysaccharides with a short in vivo lifetime, combining the function of a physical barrier and its own biological activity. Surgical barrier materials perform a barrier function until healing takes place in order to eliminate the problems created by non-biodegradable materials (infection, calcification of implants, scar formation and the need for repeated operations to remove biomaterial, etc.). Moreover, the components of surgical barrier materials have anti-inflammatory, antioxidant, wound healing activity by themselves, without the addition of pharmacological substances.

Thus, a possible mechanism for preventing the formation of polysaccharides of apple pectin or apple pectin and chitosan polysaccharides (with a degree of deacetylation of 38-100% and a molecular weight of 25-230 kDa) with calcium chloride by surgical barrier materials is a combination of the physical barrier function and the bioactivity of the components of the biomaterial.

Specific forms of the present invention will now be described in more detail using examples.

Example 1. Obtaining surgical barrier material based on apple pectin

To obtain a surgical barrier material, 13.32 mg of anhydrous calcium chloride is dissolved in 1 ml of a 0.25% aqueous solution of acetic acid with stirring. A solution of calcium chloride with a volume of 1 ml is poured into a mold and frozen at -18 ± 1 ° C for 1 hour. Apple pectin weighing 20 mg is dissolved in 2 ml of distilled water with stirring. Then a solution of apple pectin is layered on a frozen solution of calcium chloride in a volume ratio of 2: 1. Surgical barrier material is formed by slowly thawing a solution of calcium chloride at a temperature of 15 ° C-25 ° C for 4-6 hours. The formed surgical barrier material is freeze-dried and then sterilized by UV radiation for 0.5 h on each side.

Example 2. Obtaining a surgical barrier material based on pectin of apple and high molecular weight chitosan

To obtain a surgical barrier material, 6.67 mg of chitosan with MM 200 kDa and DM 95% (Chit200 / 95) is dissolved in 1 ml of a 0.25% acetic acid solution with stirring. Then, 13.32 g of anhydrous calcium chloride are added to the chitosan solution and stirred until complete dissolution. A solution of chitosan with calcium chloride in a volume of 1 ml is poured into a mold and frozen at a temperature of -18 ° C for 1 h. Apple pectin weighing 20 mg is dissolved in 2 ml of distilled water with stirring. Then, a solution of apple pectin is layered on a frozen solution of chitosan with calcium chloride in a volume ratio of 2: 1, while the mass ratio of pectin and chitosan in the composition of the surgical barrier material is 3: 1. Surgical barrier material is formed by slowly thawing a solution of calcium chloride at a temperature of 15 ° C-25 ° C for 4-6 hours. The formed surgical barrier material is freeze-dried and then sterilized by UV radiation for 0.5 h on each side.

Example 3. Obtaining a surgical barrier material based on apple pectin and depolymerized chitosan

Analogously to example 2, but add chitosan with MM 25 kDa and diabetes 98% (Chit25 / 98).

Example 4. Obtaining surgical barrier material based on apple pectin and reacetylated chitosan

Analogously to example 2, but add chitosan with MM 230 kDa and DM 38% (Chit230 / 38).

Example 5. Obtaining a surgical barrier material based on apple pectin and deacetylated chitosan

Analogously to example 2, but add chitosan with MM 150 kDa and diabetes 98% (Chit150 / 98).

The results of the study of the physico-mechanical characteristics of the surgical barrier material.

To study the mechanical strength, samples of a surgical barrier material measuring 15 × 15 mm and a thickness of 1 mm were fixed on a TA texture analyzer platform. XTplus (Stable Micro Systems, UK). The puncture strength of the surgical barrier material was evaluated. For this, a cylindrical probe p / 2 with a diameter of 2 mm was used. All measurements were carried out at room temperature, the test speed of 0.5 mm / s. On the stress – strain curve, the probe pressure force (F _max ) was fixed at which the surgical barrier material was punctured. The tensile strength was calculated using Exponent Software (version V6.1.5.0).

The mechanical strength of the surgical barrier material based on apple pectin and chitosan is presented in table 1. The strength of the pectin-chitosan surgical barrier materials based on apple pectin depends on the type of chitosan used for the preparation. Chitosans with high diabetes increase the strength of the surgical barrier material from apple pectin 3-5 times. In this case, the maximum strength (513 kPa) has a surgical barrier material based on apple pectin and low molecular weight chitosan with high DM Chit25 / 98. High molecular weight chitosan with low DM Hit230 / 38 does not affect the strength of the surgical barrier material from apple pectin, which is about 147 kPa.

To assess the elastic modulus, samples of surgical barrier materials with a size of 15 × 15 mm and a thickness of 1 mm, previously soaked in distilled water for 3 min, were fixed on a TA texture analyzer platform. XTplus (Stable Micro Systems, UK). The pressure force of a cylindrical probe p / 2 with a diameter of 2 mm was fixed on the surface of the surgical barrier material at room temperature, and the testing speed was 0.5 mm / s. The elastic modulus was calculated at 10% strain in accordance with the following equation [17]:

where E is the elastic modulus, F is the applied force, A is the cross-sectional area of the test sample, l is the initial height of the sample, Δl is the change in height under the influence of the applied force. For each type of surgical barrier material, five samples were analyzed. The average modulus of elasticity has been determined.

As a result of comparative studies, it was proved that the elasticity of samples of surgical barrier materials made from apple pectin and chitosan is close to the elasticity of human soft tissues, which is 10-75 kPa, on which the surgical barrier material is adhered during the operation, therefore, the developed materials are biomechanically compatible [18].

To evaluate the adhesive properties of pectin-chitosan surgical barrier materials, the adhesion strength of the samples to the serous membrane of the abdominal wall of laboratory rats was determined. The adhesion force was measured on each side of the surgical barrier material using a TA texture analyzer. XTplus (Stable Micro Systems, UK). A 5 × 5 mm sample was fixed using double-sided tape on a p / 0.5R cylindrical probe with a diameter of 12.7 mm. Adhesion was evaluated by the force of separation of the probe from the tissue after 60 s of pressure with a load of 0.1 N [19]. Adhesion strength was calculated using Exponent Software (version V6.1.5.0).

The adhesion of the surgical barrier material to biological tissues has been shown to increase with the introduction of chitosan with high MM and diabetes. The inclusion of chitosan Hit150 / 98 in the composition of the surgical barrier material increases the adhesion of the sides of the surgical barrier material to the serous membrane of the abdominal wall by 68%. Chitosan Chit200 / 98 increases the adhesiveness of the surgical barrier material from apple pectin by 27%. It was found that both sides of the surgical barrier material (pectin layer and chitosan layer) have comparable adhesiveness. The results obtained in the study are presented in table 1.

Thus, the inclusion of chitosan in the composition of the surgical barrier material enhances the adhesion of biomaterials to the serous membrane of the abdominal wall of laboratory rats, as well as increase their strength.

The use of surgical barrier materials to prevent postoperative adhesions in the abdominal cavity

The effectiveness of the developed surgical barrier materials was evaluated under the development of adhesions in laboratory animals. Adhesive disease was simulated in rats-females of the Wistar strain, weighing 180-200 g. For the severity of adhesion formation using manufactured surgical barrier materials, a study was conducted on adhesion formation models between the cecum and the lateral abdominal wall of rats lasting 7 days using surgical barrier materials in comparison with controls. The determination of the overall effectiveness of each test surgical barrier material was based on a comparison with the control regarding the extent of adhesion formation and the severity of the resulting adhesions.

The test surgical barrier material was considered successful if, according to the test results, it had better performance compared to the negative control, which was used as a standard suture material in this study.

Surgical procedures.

An incision of approximately 3 cm was made along the midline of the anterior wall of the abdominal cavity. The cecum was removed to the surface and a portion of its surface was rubbed with an area of 1 × 1 cm until spot bleeding was obtained. The muscle layer of a 1 × 1 cm site on the side wall of the abdominal cavity adjacent to the cecum was rubbed to obtain spot bleeding using a sterile dental drill. The damaged cecum was placed back into the abdominal cavity near the damaged abdominal wall. Surgical barrier material 1.5 × 1.5 cm in size soaked in sterile physiological saline was placed between damaged surfaces for 3 minutes. The control group of rats did not receive treatment of their wound surfaces before closing the abdominal cavity. After the procedure, the abdominal cavity was closed with 3-0 silk sutures, and the skin was closed with 4-0 silk sutures.

7 days after the operation, the animals were euthanized using an overdose of CO ₂ gas. The abdominal cavity was opened with a U-shaped incision and a blind assessment of the severity of adhesion on the adhesion scale was performed [20].

Scale of adhesion formation in an in vivo experiment:

0 points - no commissures;

1 point - thin film adhesion;

2 points - several thin adhesions;

3 points - thickened commissure with pin attachment;

4 points - a thickened adhesion with a flat attachment;

5 points - very thick blood supply adhesions.

The test results are shown in table 2.

During the study of anti-adhesion activity, it was found that adhesion formation reaches a level of 4 points out of 5 in control animals. In animals on which surgical barrier materials based on apple pectin were placed on the wound surfaces, adhesion is significantly reduced compared to the control group. The median value on the scale for assessing adhesion formation is 0 ± 0.5 points (Table 2). When chitosan Chit150 / 98, Chit200 / 95, Chit230 / 38 is added to the composition of the surgical barrier material based on apple pectin, a decrease in adhesion also occurs. The groups had a significantly lower spike formation score compared to the control. As shown in table 2, when treating wound surfaces with surgical barrier material with chitosan Khit150 / 98 and Khit200 / 95, there is a decrease in adhesion compared to the control to 2 points on the scale (there are several thin adhesions). In the case of using surgical barrier material with Chitosan Chit230 / 38, adhesion decreases to 1 ± 0.5 points (one thin film adhesion). Significant differences were not observed between the surgical barrier material with chitosan Chit25 / 98 and the control group. In most rats, when using surgical barrier material based on apple pectin, adhesions did not form, and defects were almost completely restored within 7 days, which indicates the effectiveness of the developed surgical barrier material to prevent adhesion formation. During the autopsy, no residual surgical barrier material was found in the treated areas (wound surfaces of the abdominal wall and / or surfaces of the cecum) or in the abdominal cavity, which indicates biodegradation of the barrier material. Thus, the greatest anti-adhesion effect in the model of traumatic damage to the lateral abdominal wall in rats is observed when using surgical barrier material based on apple pectin (0 ± 0.5 points), as well as when re-acetylated chitosan with low DM 230/38 is added to the composition of the barrier material (1 ± 0.5 points).

The results of determining the biodegradation time of surgical barrier materials in vivo.

The biodegradation time of the samples of surgical barrier material was determined under conditions of modeling the adhesion process in female Wistar rats. 15 female Wistar rats were randomly divided into 5 groups of 3 animals per group. In 5 groups of animals, the biodegradation time of samples of surgical barrier material based on apple pectin was studied. One animal from each group was removed from the experiment after 4 and 24 hours. At certain intervals, the abdominal cavity was opened, the presence of cryogels in the abdominal cavity was evaluated visually.

A typical picture of the biodegradation of apple pectin-based surgical barrier material is shown in Figure 1. During the determination of the biodegradation time, it was found that after 4 hours in the abdominal cavity, all surgical apple pectin-based barrier materials lose their shape and are destroyed when removed from the abdominal cavity. Complete biodegradation of the surgical barrier material occurs after 24 hours of incubation.

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Claims (2)

1. A method of producing a polysaccharide-based surgical barrier material, comprising dissolving pectin in water and then applying it to a solution of calcium chloride or chitosan pre-frozen at minus 18 ± 1 ° C with calcium chloride, characterized in that apple pectin is used, and calcium chloride or chitosan and calcium chloride are dissolved in a 0.25% aqueous acetic acid solution, the resulting solution is frozen, then apple pectin solution is layered on a frozen solution of calcium chloride or chitosan and chlorine calcium oxide, while the mass ratio of pectin and chitosan in the composition of the surgical barrier material is 3: 1, the formation of the surgical barrier material takes place by slowly thawing the frozen solution for 4-6 hours at a temperature of 15 ° C-22 ° C, after which the formed surgical The barrier material is freeze-dried and then sterilized by UV radiation. 2. The method according to p. 1, characterized in that use chitosan with a degree of deacetylation of 38-100% and a molecular weight of 25-230 kDa.

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