Disulfide-crosslinked hyaluronic acid gel for preventing postoperative abdominal (pelvic) adhesions and method for preparing same

Abstract

Disulfide-crosslinked hyaluronic acid gelatin for preventing postoperative abdominal (pelvic) adhesions, containing 3-8 mg / mL of disulfide-crosslinked hyaluronic acid, and a method for preparing the same. Disulfide-crosslinked hyaluronic acid gelatin not only has good biocompatibility, but also exhibits good anti-tissue adhesion effects when used to prevent postoperative abdominal (pelvic) adhesions.

Description

[Technical field]

[0001] The present invention relates to the field of biomedicine, in particular to a disulfide-crosslinked hyaluronic acid gel for preventing postoperative abdominal (pelvic) adhesion, and to a method for preparing the disulfide-crosslinked hyaluronic acid gel for preventing postoperative abdominal (pelvic) adhesion. [Background technology]

[0002] Postoperative adhesions are an unavoidable pathophysiological phenomenon that occurs during the natural healing process. In the body, fibrous bands formed by scar tissue cause normal tissues and organs that should not normally adhere to each other to abnormally adhere together. Tissue adhesions are usually most serious in postoperative abdominal (pelvic) adhesions, with an incidence rate of 90%. becomes higher than Postoperative complications include intestinal obstruction, secondary infertility, and abdominal (pelvic) pain. (Sikirica et al., BMC Surg. 2011, 11:13; ten Broek et al., BMJ 2013, 347: f5588).

[0003] During surgery, great care must be taken to prevent the formation of postoperative adhesions, but adhesions are part of the natural healing process and cannot be prevented even with meticulous surgical techniques. In addition, no treatments or "magic bullets" are currently available to reduce adhesions after they have formed. Many patients with adhesion-related complications require repeat surgery for diagnosis. If adhesions from a previous surgery are found, adhesion lysis must be performed to dissolve the adhesions. Although adhesion removal provides a solution for some patients, adhesions often recur. Therefore, the current focus is on adhesion prevention and the development of safe and effective adhesion prevention products (DeWilde et al., Gynecol Surg. 2007, 4; 243-253 ).

[0004] An adhesion barrier can physically isolate damaged tissue during the repair process, so theoretically it can effectively reduce adhesion formation. An ideal adhesion barrier would be safe, biodegradable and absorbable, applicable after both open and laparoscopic surgery, and able to effectively prevent the formation of postoperative abdominal (pelvic) adhesions. Currently, several adhesion barriers are approved for use in postoperative abdominal (pelvic) adhesions, but there are differences in indications, efficacy, and safety, and significant improvements are still needed (Tulandi et al., Curr Opin Obstet Gynecol . 2005, 17: 395-398; DeWilde et al., Gynecol Surg. 2007, 4: 243-253; Arung et al., World J Gastroenterol. 2011, 17: 4545-4553; Practice Committee of the American Society for Reproductive Medicine in collaboration with the Society of Reproductive Surgeons, Fertil Steril. 2013, 99: 1550-1555).

[0005] Hyaluronan is a nonsulfonated glycosaminoglycan consisting of repeating disaccharide units (α-1,4-D-glucuronic acid and β-1,3-N-acetyl-D-glucosamine), and is the main component of the extracellular matrix of connective tissues. It has excellent biocompatibility, unique physical and chemical properties, and biological functions such as promoting wound healing. Hyaluronan was once considered to be an ideal adhesion barrier. However, due to its fluidity and rapid degradation by hyaluronidase in vivo, hyaluronan cannot effectively physically separate injured tissues during the repair process and therefore cannot significantly prevent adhesions (Wiseman, In:dizeraga GS., Editor. New York: Springer-Verlag; 2000, pp 401-417).

[0006] Cross-linking can significantly reduce the fluidity of hyaluronic acid and delay its degradation and absorption in vivo. Cross-linked hyaluronic acid can effectively separate damaged tissues during the repair process. Therefore, it has a good potential for preventing postoperative abdominal (pelvic) adhesions. However, inappropriate cross-linking can also impair the biocompatibility of hyaluronic acid. For example, sodium hyaluronate gel cross-linked with trivalent iron ions has caused many serious adverse events (Wiseman, Ann Surg. 2006, 244: 630-632).

[0007] In a prior patent document (CN 102399295A), the present applicant disclosed a disulfide cross-linked hyaluronic acid gel that maintains the original structure, physiological function and biocompatibility of hyaluronic acid to the maximum extent possible, while at the same time delaying the decomposition, absorption and dissolution fluidity of hyaluronic acid in the body. However, the application of the gel to prevent postoperative abdominal (pelvic) adhesions was not discussed in detail. Summary of the Invention

[0008] The present invention provides a disulfide-crosslinked hyaluronic acid gel that has good biocompatibility and is highly effective in preventing tissue adhesions such as postoperative abdominal (pelvic) adhesions.

[0009] The present invention is realized by the following technical solutions. A disulfide-crosslinked hyaluronic acid gel for preventing tissue adhesion in postoperative abdominal (pelvic) adhesions, characterized in that the content of disulfide-crosslinked hyaluronic acid in the gel is 3 to 8 mg / mL.

[0010] In the present invention, the content of disulfide-crosslinked hyaluronic acid is expressed as the weight (mg / mL) of disulfide-crosslinked hyaluronic acid in each volume unit of disulfide-crosslinked hyaluronic acid gel, and is preferably 4 to 7 mg / mL, and particularly preferably 4.5 to 6 mg / mL.

[0011] Anti-adhesion prevents adhesion by physically isolating damaged tissue during its repair process.As known to those skilled in the art, the strength of cross-linked hyaluronic acid gel increases with the content of cross-linked hyaluronic acid, which can provide better physical isolation effect, and therefore should have better anti-adhesion effect.For those skilled in the art, in order to further improve the anti-adhesion effect of disulfide cross-linked hyaluronic acid gel, it is foreseen that the technical solution is to increase the content of disulfide cross-linked hyaluronic acid, and it is easy for those skilled in the art to think of increasing the content of disulfide cross-linked hyaluronic acid.

[0012] Prior patent literature (CN 102399295A) discloses that disulfide bond cross-linked hyaluronic acid gel (10 mg / mL) has a superior abdominal (pelvic) adhesion prevention effect to non-cross-linked hyaluronic acid solutions. Therefore, it is expected according to common sense that the abdominal (pelvic) adhesion prevention effect can be further improved by increasing the content of disulfide bond cross-linked hyaluronic acid gel (Yang et al., BMC Biotechnology 2010, 10:65; De Iaco et al., Fertil Steril. 1998, 69: 318-323).

[0013] However, the present inventors have discovered that, contrary to common knowledge well known to those skilled in the art, a disulfide-bond cross-linked hyaluronic acid gel with a low content of disulfide-bond cross-linked hyaluronic acid (3 to 8 mg / mL) is more effective in preventing postoperative abdominal (pelvic) adhesions than one with a high content (10 mg / mL), and also has good biocompatibility, which led to the completion of the present invention.

[0014] The technical solutions adopted by the present invention are beyond common sense, and the beneficial effects obtained are unexpected.

[0015] Another object of the present invention is to provide a method for preparing disulfide cross-linked hyaluronic acid gel for preventing tissue adhesion of postoperative abdominal (pelvic) adhesion.The technical scheme of the preparation method of the present invention is to obtain the disulfide cross-linked hyaluronic acid gel of the present invention by oxidizing the aqueous solution of hyaluronic acid thiolated derivative.

[0016] The above oxidation treatment can be generally carried out under the action of oxygen, such as oxygen in air and / or oxygen dissolved in an aqueous solution. In this process, thiol groups are oxidized to form disulfide bonds without the addition of a crosslinking agent, and water is obtained as a by-product, without the need for further purification. In the above preparation process, the aqueous solution of hyaluronic acid thiolated derivative is sterilized by filtration, and then the disulfide crosslinked hyaluronic acid gel of the present invention can be prepared in an aseptic state. Alternatively or additionally, terminal sterilization and the like can also be used for sterilization. Terminal sterilization methods include moist heat sterilization and the like, which are well known to those skilled in the art.

[0017] In the present invention, the hyaluronic acid thiolated derivative refers to the hyaluronic acid derivative having a thiol group that can be prepared by thiol-modifying hyaluronic acid, and also includes the thiolated derivative prepared by various hyaluronic acid derivatives (carboxymethylated hyaluronic acid, acetylated hyaluronic acid, etc.) through thiol modification.The side chain carboxyl group, side chain hydroxyl group, and reducing end group of hyaluronic acid or its derivative are usually active functional groups that can be thiol-modified, and the hyaluronic acid thiolated derivative of the present invention can be prepared by using various preparation methods of hyaluronic acid thiolated derivatives disclosed in prior art documents such as patent document WO 2009 / 006780A1.These hyaluronic acid thiolated derivatives preferably maintain the original structure, physiological function, and biocompatibility of hyaluronic acid, achieve effective disulfide crosslinking, and significantly delay decomposition, absorption, and fluidity in vivo.

[0018] In the present invention, the disulfide-bridged hyaluronic acid of the present invention can be prepared using thiolated hyaluronic acid derivatives with various thiol contents. The thiol content is expressed as the number of thiolated hyaluronic acid derivatives per gram of hyaluronic acid derivative. Thiol The thiol content is expressed in micromoles (μmol / g) and is preferably 10 to 100 μmol / g, and particularly preferably 20 to 70 μmol / g.

[0019] In the present invention, hyaluronic acid also includes its salt forms (sodium salt, potassium salt, zinc salt, calcium salt, etc.). The beneficial effects of the present invention are as follows:

[0020] The disulfide cross-linked hyaluronic acid gel for preventing tissue adhesion of postoperative abdominal (pelvic) adhesion according to the present invention adopts a technical solution contrary to common sense well known to those skilled in the art, and not only has good biocompatibility but also achieves an unexpected effect of preventing tissue adhesion of postoperative abdominal (pelvic) adhesion. The preparation method according to the present invention has many advantages, such as no need to add a cross-linking agent, simple preparation process, no impurities, etc. [Brief description of the drawings]

[0021] [Figure 1] Effect of disulfide-crosslinked hyaluronic acid content on gel dynamic viscosity. [Diagram 2] Effect of disulfide-crosslinked hyaluronan content on the area involved in adhesion. [Diagram 3] Effect of disulfide-linked hyaluronic acid content on adhesion severity. [Figure 4] Effect of disulfide-crosslinked hyaluronic acid content on adhesion length. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples. However, those skilled in the art will understand that the following examples are only used to explain the present invention and should not be considered as limiting the scope of the present invention.

[0023] Example 1: Preparation of disulfide cross-linked hyaluronic acid gel The thiolated hyaluronic acid derivatives were prepared from sodium hyaluronate with a molecular weight of 180KDa by the method reported by Shu et al. (Shu et al., Biomacromolecules 2002, 3: 1304-1311). The thiol contents of the derivatives were 24μmol / g, 38μmol / g, and 57μmol / g, respectively.

[0024] The above hyaluronic acid thiolated derivatives were dissolved to obtain aqueous solutions with the contents of 3mg / mL, 4mg / mL, 4.5mg / mL, 5mg / mL, 6mg / mL, 7mg / mL, 8mg / mL and 10mg / mL, respectively. The pH value of the solution was adjusted to 7.4. After sterilization by filtration, the solution was transferred to a sterile glass container. When the solution was stored at room temperature for 4 weeks, the solution lost its fluidity and formed a disulfide-crosslinked hyaluronic acid gel.

[0025] Example 2: Evaluation of dynamic viscosity characteristics of disulfide cross-linked hyaluronic acid gel The dynamic viscosity characteristics of the disulfide-crosslinked hyaluronic acid gel prepared in Example 1 were evaluated using a rotational viscometer at a shear rate of 0.25 Hz or more (25±0.1°C) in accordance with Method 2 of Appendix VIG, Part 2 of the Chinese Pharmacopoeia (2010 edition).

[0026] Visually, gels with a higher content of disulfide-crosslinked hyaluronic acid have higher strength, and tests have shown that gels with a higher content have a higher dynamic viscosity. Figure 1 shows the effect of the content of disulfide-linked hyaluronic acid on the dynamic viscosity of the gel. The gel with a content of 10 mg / mL of disulfide-linked hyaluronic acid had the highest dynamic viscosity ( 100,000 mPa s or more), which exceeds the upper limit of the measurement 100,000 It is stated as mPa·s or more.

[0027] The thiol content of the thiolated derivative of hyaluronic acid also has a certain effect on the dynamic viscosity of the gel. Gels prepared from thiolated derivatives of hyaluronic acid with a high thiol content have a higher dynamic viscosity.

[0028] Example 3: Cytocompatibility evaluation of disulfide cross-linked hyaluronic acid gel The in vitro cytotoxicity of the disulfide bond cross-linked hyaluronic acid gel prepared in Example 1 was evaluated with reference to the ISO10993.5-2009 standard. Rat fibroblasts (ATCC CCL1, NCTC Clone 929, Clone of Strain L) were cultured in RPMI 1640 medium containing antibiotics (100 μg / mL penicillin, 100 μg / mL streptomycin) and 10% serum at 37°C, 5% CO2, and saturated humidity. When the cells grew to near confluence, Trypsin Digest the cells at 5x10 and harvest the cells. 4 Adjust to / mL.

[0029] The extraction medium used was RPMI 1640 medium containing 10% serum. 0.2 g of disulfide-crosslinked hyaluronic acid gel was added per 1 ml of extraction medium. Leaching was carried out at 37°C for 24 hours. Next, the original leaching solution was diluted with RPMI 1640 containing 10% serum to obtain four diluted leaching solutions with the original leaching solution contents of 100%, 50%, 25%, and 12.5%, respectively.

[0030] Add the above cell suspension to a 96-well plate, 100 μL (5 × 10 3 The cells were cultured at 37℃ and 5% CO2 for 24 hours. The medium was discarded, and the diluted leachate (100%, 50%, 25%, and 12.5% ​​in four doses) for each group, negative control, blank control, and positive control were added to five wells of each group, and cultured at 37℃ in a 5% CO2 saturated steam incubator for 24 hours.

[0031] After culturing, remove the cell culture plate, discard the medium, add 100 μL of RPMI 1640 medium containing 10% serum, add 50 μL (1 mg / mL) of MTT staining solution to each well, and culture for 3 hours at 37°C in a 5% CO2 saturated steam incubator. Discard the medium from the culture plate, add 100 μL of isopropanol to each well, shake, and measure the absorbance at a wavelength of 570 nm.

[0032] The relative cell proliferation rate was calculated from the ratio of the absorption value of each group to the absorption value of the blank control group, and the relative cell proliferation rate of the blank control group was set to 100%.

[0033] The relative cell proliferation rate of the negative control group was the same as that of the blank control group, and the relative cell proliferation rate of the positive control group was less than 10%, which was as expected. The relative proliferation rate of the cells in each disulfide cross-linked hyaluronic acid gel test group was more than 90%, and no cytotoxicity was observed in the cells, indicating that the tested disulfide cross-linked hyaluronic acid gels have good cytocompatibility.

[0034] Example 4: In vivo tissue compatibility evaluation of disulfide cross-linked hyaluronic acid gel The in vivo tissue compatibility of the nine disulfide-crosslinked hyaluronic acid gels prepared in Example 1 was evaluated with reference to the ISO10993.6-2007 standard. The disulfide-crosslinked hyaluronic acid contents of these nine gels were 3mg / mL, 6mg / mL, and 8mg / mL, respectively, and these nine gels were prepared using hyaluronic acid thiolated derivatives with thiol contents of 24μmol / g, 38μmol / g, and 57μmol / g, respectively. A commercially available non-crosslinked hyaluronic acid gel product was used as a control sample.

[0035] After the skin of healthy SD rats was disinfected as usual, the disulfide cross-linked hyaluronic acid gel prepared in Example 1 or a control sample (0.5 mL) was implanted subcutaneously (2 cm away from the spine) along the midline of the rat's spine. The rats were painlessly sacrificed 3, 7, 10, and 14 days after implantation. The implants and their surrounding tissues were excised and observed macroscopically. The implants and their surrounding tissues were fixed in 10% formalin, dehydrated in gradient alcohol, embedded in paraffin, sliced, stained with HE, and observed and evaluated histopathologically.

[0036] Visual observation of the gels and control samples showed slight redness and edema at the wound of the rats three days after implantation, but these gradually disappeared with increasing implantation time. Histopathological observation confirmed that the tissue reaction in each gel group was mild, similar to that of the control sample. These test results show that the disulfide cross-linked hyaluronic acid gels tested showed good tissue adhesion. Compatibility It has been shown that this compound has

[0037] Example 5: Preparation of disulfide cross-linked hyaluronic acid gel The thiolated hyaluronic acid derivatives were prepared by the method reported by Wang et al. (Wang et al., J Mater Chem. B, 2015, 3:7546-7553) using sodium hyaluronate with molecular weights of 300KDa and 1500KDa. Their thiol contents were 103μmol / g and 75μmol / g, respectively.

[0038] The above hyaluronic acid thiolated derivatives were dissolved to obtain aqueous solutions with contents of 3 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, and 10 mg / mL. The pH value of the solution was adjusted to 7.4. The solution was transferred to a glass container and sterilized by moist heat. The solution was placed in a sealed container and stored at room temperature for 4 weeks. The solution lost fluidity and formed a disulfide-crosslinked hyaluronic acid gel.

[0039] Example 6: Cells in disulfide cross-linked hyaluronic acid gels Compatibility Sexual evaluation The in vitro cytotoxicity of the disulfide bond cross-linked hyaluronic acid gel prepared in Example 5 was evaluated in the same manner as in Example 3. The relative proliferation rate of cells in each disulfide cross-linked hyaluronic acid gel test group was 90% or more, and no cytotoxicity was observed in the cells, indicating that the disulfide cross-linked hyaluronic acid gels tested have good cytocompatibility.

[0040] Example 7: In vivo tissue compatibility evaluation of disulfide cross-linked hyaluronic acid gel The in vivo tissue compatibility of the four disulfide bond cross-linked hyaluronic acid gels prepared in Example 5 was evaluated in the same manner as in Example 5. Two of the gels were prepared using a hyaluronic acid thiolated derivative with a thiol content of 75 μmol / g (1500 KDa), and the other two gels were prepared using a hyaluronic acid thiolated derivative with a thiol content of 103 μmol / g (300 KDa). The contents of disulfide cross-linked hyaluronic acid in the gels were 3 mg / mL and 4.5 mg / mL, respectively. A commercially available non-cross-linked hyaluronic acid gel product was used as a control sample.

[0041] Visual observation of the gels and control samples showed slight redness and edema at the wound site of the animals three days after implantation, which gradually disappeared with increasing implantation time. Histopathological observation confirmed that the tissue reaction in each gel group was mild, similar to that of the control sample. The test results showed that the disulfide cross-linked hyaluronic acid gels tested showed good tissue reactivity. Compatibility It was found that it has

[0042] Example 8: Evaluation of the effect of disulfide-crosslinked hyaluronic acid gel in preventing abdominal (pelvic) adhesion Using the classic white rabbit side wall model (John et al., Fertil Steril. 1997, 68: 37-42), the anti-abdominal (pelvic) adhesion effect of the disulfide bond cross-linked hyaluronic acid gel prepared in Example 1 was evaluated. The disulfide cross-linked hyaluronic acid gel used was prepared from a hyaluronic acid thiolated derivative with a thiol content of 38 μmol / g, and the contents of disulfide cross-linked hyaluronic acid in the gel were 3 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, and 10 mg / mL, respectively.

[0043] A healthy female white rabbit was anesthetized with an intramuscular injection of a mixture of ketamine hydrochloride (55 mg / kg) and troponin (5 mg / kg), and a midline laparotomy was performed on the rabbit. The cecum and small intestine were removed, and pressure was applied to bleed under all serosal surfaces, gently scraping the damaged intestine with sterile gauze until punctate bleeding was observed. The cecum and small intestine were returned to their anatomical normal position. A 5 × 3 cm section was placed on the right side of the abdominal wall.2 Resect the peritoneum and transversus abdominis muscle over an area of ​​100 mm. Apply disulfide-crosslinked hyaluronic acid gel (~4 mL) or saline to the resected area. The surgical incision is closed with two layers of absorbable sutures, and care is taken during surgery to avoid damaging the intestine.

[0044] The experimental animals were sacrificed on the 21st day after surgery, and general observations were performed under laparotomy. At the same time, the percentage of adhesion area associated with side wall damage and the severity of adhesions were measured and evaluated. The severity of adhesions was scored according to the quartile method: 0 = no adhesions, 1 = mild adhesions (easily removable adhesions), 2 = moderate adhesions (cannot be removed, organs do not tear), 3 = dense adhesions (cannot be removed, organs tear when moved).

[0045] Macroscopic observation showed no symptoms of chronic inflammation or granuloma, indicating that the tested disulfide cross-linked hyaluronic acid gel had good tissue compatibility. At the same time, no gel residue was found, indicating that the tested disulfide cross-linked hyaluronic acid gel was completely degraded and absorbed.

[0046] The evaluation results are shown in Figure 2 (percentage of adhesion area) and Figure 3 (severity of adhesion). All of the tested disulfide cross-linked hyaluronic acid gels had an adhesion prevention effect, and it was found that the gels with contents of 3 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, and 8 mg / mL were superior in adhesion prevention effect (smaller adhesion area and less severity of adhesion) compared to the 10 mg / mL gel.

[0047] Example 9: Evaluation of the effect of disulfide-crosslinked hyaluronic acid gel in preventing abdominal (pelvic) adhesion In order to evaluate the anti-abdominal (pelvic) adhesion effect of the disulfide bond cross-linked hyaluronic acid gel prepared in Example 1, a classical white rabbit uterusA horn model (John et al., FertilSteril. 1997, 68: 37-42) was used. The disulfide-crosslinked hyaluronic acid gels used were prepared from thiolated hyaluronic acid derivatives with a thiol content of 57 μmol / g, and the contents of disulfide-crosslinked hyaluronic acid in the gels were 3 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, and 10 mg / mL, respectively.

[0048] Healthy female white rabbits were anesthetized with an intramuscular injection of 3% sodium pentobarbital (3 mg / kg), and the abdominal cavity was opened along the linea alba to expose both uterus and oviducts, and the uterine horns were located. The diameter of the uterine horns was measured and recorded. Only white rabbits with a uterine horn diameter of 3 mm or more were allowed to continue the study. Using a No. 10 surgical knife, the uterine horns were scratched approximately 20 times, starting from the uterine horns, 1 cm from the oviducts, and 4 cm from the uterine body, until intermittent bleeding on the serosal surface was visible to the naked eye. The injured uterus and oviducts were returned to their original natural anatomical sites, and 2.5 mL of disulfide-linked hyaluronic acid gel or normal saline was applied to each side of the wound. Before closing the abdomen, 5 mL of disulfide-linked hyaluronic acid gel or normal saline was injected into the abdominal cavity from the caudal end of the abdominal wall incision using a syringe.

[0049] The test animals were sacrificed two weeks after surgery, and the abdominal cavity was opened to observe the general condition, such as the position and appearance of the main organs, ascites, and residual test specimens. The uterus and oviducts were exposed, and adhesions to the uteri and oviduct or surrounding organs were determined. The adhesion lengths of each were measured, and the adhesion lengths of both uteri and oviducts were added together to calculate the postoperative adhesion length of the animal.

[0050] Rough observations showed that no side effects were observed and the tested disulfide cross-linked hyaluronic acid gel had good tissue compatibility. At the same time, no gel residue was found, indicating that the tested disulfide cross-linked hyaluronic acid gel was completely decomposed and absorbed. For the evaluation results, please refer to Figure 4. All of the disulfide cross-linked hyaluronic acid gels tested had an adhesion prevention effect, with gels with contents of 3 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, and 8 mg / mL having a superior adhesion prevention effect (reduced adhesion length) compared to the 10 mg / mL gel, and the 5 mg / mL content was also found to have a superior adhesion prevention effect (reduced adhesion length).

[0051] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the examples. Any other changes, modifications, combinations, substitutions and simplifications made within the scope of the spirit and principle of the present invention should be replaced with equivalents, and all fall within the protection scope of the present invention.

Claims

1. The content of disulfide cross-linked hyaluronic acid is 3 to 8 mg / mL. The disulfide cross-linked hyaluronic acid gel is prepared by a thiolated derivative of hyaluronic acid; The thiol content of the hyaluronic acid thiolated derivative is 10 to 100 μmol / g: A disulfide-crosslinked hyaluronic acid gel for preventing tissue adhesion after abdominal (pelvic) surgery, characterized by:

2. 2. The disulfide-crosslinked hyaluronic acid gel for preventing tissue adhesion after abdominal (pelvic) surgery according to claim 1, wherein the content of disulfide-crosslinked hyaluronic acid is 3 to 4.5 mg / mL.

3. 2. The disulfide-crosslinked hyaluronic acid gel for preventing tissue adhesion after abdominal (pelvic) surgery according to claim 1, wherein the thiolated hyaluronic acid derivative has a thiol content of 20 to 70 μmol / g.

4. 4. The method for preparing a disulfide-crosslinked hyaluronic acid gel according to claim 1, wherein the disulfide-crosslinked hyaluronic acid gel is prepared from an aqueous solution of a thiolated hyaluronic acid derivative via an oxidation step.

5. 5. The method for preparing a disulfide-crosslinked hyaluronic acid gel according to claim 4, wherein the oxidation step is carried out under the action of oxygen.

6. 6. The method for preparing a disulfide-crosslinked hyaluronic acid gel according to claim 5, wherein the oxygen is oxygen in the air and / or oxygen dissolved in an aqueous solution.

7. 4. The disulfide-crosslinked hyaluronic acid gel according to claim 1, for use in a method for preventing tissue adhesions after abdominal (pelvic) surgery.

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