Polyethylene glycol modified prrp31 and preparation and use thereof

Abstract

This invention relates to a polyethylene glycol-modified PrRP31, its preparation, and its application. The invention involves modifying PrRP31 with polyethylene glycol and testing its anti-inflammatory activity in a mouse paw edema model and its analgesic activity in a mouse water bath tail-flick experiment. Using polyethylene glycol-modified PrRP31, a mouse paw edema model, and a water bath tail-flick experiment, the anti-inflammatory and analgesic activities of polyethylene glycol-modified PrRP31 were tested. The experiments demonstrated that polyethylene glycol-modified PrRP31 possesses good anti-inflammatory and analgesic activity. In the mouse paw edema model, polyethylene glycol-modified PrRP31 inhibited inflammation by 37.09% (5 h) at a concentration of 5 mg / kg. In the mouse water bath tail-flick experiment, polyethylene glycol-modified PrRP31 produced the maximum analgesic effect at a concentration of 5 mg / kg. This invention provides an application of polyethylene glycol-modified PrRP31 as an anti-inflammatory and analgesic drug, offering beneficial assistance in the treatment of related diseases and possessing significant importance in the pharmaceutical field.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical application technology, and relates to a polyethylene glycol-modified PrRP31 and its preparation method, as well as the pharmaceutical application of polyethylene glycol-modified PrRP31, especially the application of polyethylene glycol-modified PrRP31 in the preparation of anti-inflammatory and analgesic drugs. Background Technology

[0002] Prolactin-releasing peptide, also known as PrRP, is a neuropeptide extracted from bovine hypothalamus. PrRP belongs to the RF-amide neuropeptide family and is the only known endogenous ligand for G protein-coupled receptor 10. In humans, PrRP has two biologically active isoforms, PrRP20 and PrRP31. Both isoforms share a common C-terminal Arg-Phe-amide sequence, which is crucial for their biological activity. PrRP31 is associated with various physiological functions, including feeding and energy expenditure regulation. Therefore, research on PrRP31 is of significant importance.

[0003] Peptides, as novel drug molecules, have been widely used in cancer treatment, tumor imaging, and immunotherapy in recent years. As drug molecules, peptides possess advantages such as low toxicity, high activity, and ease of synthesis and modification. However, due to their susceptibility to degradation by various proteases, peptides exhibit poor in vivo stability, limiting their practical applications. Polyethylene glycol (PEG) is an ethylene oxide polymer, characterized by its non-ionic nature, non-toxicity, lack of biorejection, and high hydrophilicity. Chemically coupling PEG to macromolecules (antibodies, peptides, etc.) can significantly improve the solubility and bioefficacy of peptides, and also prolong their metabolic time. Currently, various modified peptide drugs are available on the market, including those modified by PEG, methylation, isotope modification, and disulfide bond modification. Among these, PEG modification is one of the most effective strategies for improving peptide drugs. Currently, there are no reports on the use of PEG-modified PrRP31 for anti-inflammatory and analgesic activity studies. Summary of the Invention

[0004] Technical problems to be solved

[0005] To avoid the shortcomings of the prior art, this invention proposes a polyethylene glycol-modified PrRP31, its preparation, and its application in anti-inflammatory and analgesic activities.

[0006] Technical solution

[0007] A polyethylene glycol-modified PrRP31, characterized by using polyethylene glycol to modify the amino-terminal Ser of PrRP31, with the molecular formula C 166H 263 N 57 O 45 S1, the structural formula is as follows:

[0008]

[0009] Where: C 166 H 263 N 57 O 45 S1 has a molecular weight of 3809.55 and an amino acid sequence of PEG2-SRTHRHSMEIRTPDINPAWYASRGIRPVGRF-NH2.

[0010] A method for preparing the polyethylene glycol-modified PrRP31, characterized by the following steps:

[0011] Step 1, Resin swelling: Add Rink-Amide-MBHA-Resin starting resin to the reaction column, and then soak it in DCM for 20-30 minutes. Then, remove the water from the reaction column.

[0012] Step 2, Deprotection: Add piperidine to a DMF solution, stir with N2 for 20-30 minutes, and filter off the solvent; then wash the resin with DMF 6-8 times and remove excess water.

[0013] Step 3: Dissolve 0.34g TBTU and the protected amino acid in 0.27ml DMF in a beaker, and stir thoroughly until completely dissolved;

[0014] Step 4: Add the reaction solution from step 3 to the resin, then add DIEA, and purge with N2 for 1-2 hours;

[0015] Step 5: After the reaction is complete, remove the solvent and wash the resin with DMF 3-5 times;

[0016] Step 6: Add a 20% piperidine DMF solution to the resin, and continue to purge with N2 for 30-40 minutes;

[0017] Step 7: Then remove the solvent and wash the resin with DMF 6-8 times to complete the coupling of this amino acid;

[0018] Repeat steps 1 through 7, replacing the starting resin from step 1 with the substance obtained in step 7 each time, until the condensation of the last amino acid is complete. Then, condense sequentially from the C-terminal residue to the N-terminal residue in the resin of the reaction column to obtain polyethylene glycol-modified PrRP31, which is a polypeptide with the following amino acid sequence:

[0019] PEG2-SRTHRHSMEIRTPD INPAWYASRGIRPVGRF-NH2.

[0020] The volume fraction of the DMF solution in step 2 is 20%.

[0021] The polyethylene glycol-modified PrRP31 obtained in the resin of the reaction column was first extracted with lysis buffer to obtain crude peptide, and then purified to obtain high-purity polypeptide.

[0022] The crude peptide is purified by adding the lysis buffer to the condensed reaction column resin and stirring for 2-3 hours; then the resin and lysis buffer are separated, and ether is added to allow the peptide in the reaction column resin to be fully extracted. After filtration, the peptide is thoroughly washed with ether 6-8 times to obtain the crude peptide.

[0023] The purification process involves: determining the peak time of the crude product by analyzing 5-95% concentration; dissolving the crude product in acetonitrile and aqueous solution; clarifying and filtering the solution; then performing gradient extraction based on the peak time; adding the resulting liquid to a flask; and rotary evaporating and freeze-drying for 3-4 days to obtain a high-purity polypeptide.

[0024] A method for using the polyethylene glycol-modified PrRP31, characterized in that: the polyethylene glycol-modified PrRP31 is used to prepare anti-inflammatory and analgesic drugs.

[0025] The formulation for preparing 1000 tablets using polyethylene glycol-modified PrRP31 is as follows: 45.0g of polyethylene glycol-modified PrRP31, 170.0g of filler, 15.0g of disintegrant, 10.0g of binder, and 5.0g of lubricant, which are then prepared into tablets according to conventional tablet preparation processes.

[0026] The formulation for preparing 1000 soft capsules using polyethylene glycol-modified PrRP31 is as follows: 90.0g of polyethylene glycol-modified PrRP31, 10.0g of binder, 80.0g of filler, and 20.0g of lubricant, prepared according to conventional capsule preparation processes.

[0027] The formulation for preparing 1000 vials of 1ml injection solution using polyethylene glycol-modified PrRP31 is as follows: 100.0g polyethylene glycol-modified PrRP31, 2.0g citric acid, 1.0g sodium citrate, 15.0g sodium chloride, and 2000ml water for injection, following the conventional process for preparing injection solutions.

[0028] Beneficial effects

[0029] This invention proposes a polyethylene glycol-modified PrRP31, its preparation, and its application. PrRP31 is modified with polyethylene glycol, and the anti-inflammatory activity of the polyethylene glycol-modified PrRP31 in a mouse paw edema inflammation model and its analgesic activity in a mouse water bath tail-flick experiment are detected. Using polyethylene glycol-modified PrRP31, a mouse paw edema inflammation model, and a water bath tail-flick experiment, the anti-inflammatory and analgesic activities of polyethylene glycol-modified PrRP31 were tested. Experiments demonstrate that polyethylene glycol-modified PrRP31 possesses good anti-inflammatory and analgesic activity. In the mouse paw edema inflammation model, polyethylene glycol-modified PrRP31 inhibited inflammation by 37.09% (5h) at a concentration of 5 mg / kg. In the mouse water bath tail-flick experiment, polyethylene glycol-modified PrRP31 produced the maximum analgesic effect at a concentration of 5 mg / kg. This invention provides an application of polyethylene glycol-modified PrRP31 as an anti-inflammatory and analgesic drug, offering beneficial assistance in the treatment of related diseases and possessing significant importance in the pharmaceutical field. Attached Figure Description

[0030] Figure 1 This is a high-performance liquid chromatography (HPLC) chromatogram of polyethylene glycol-modified PrRP31 according to the present invention.

[0031] Figure 2 This is the mass spectrometry identification diagram of polyethylene glycol modified PrRP31 according to the present invention.

[0032] Figure 3 This study evaluated the anti-inflammatory activity of polyethylene glycol-modified PrRP31 using a mouse paw edema inflammation model. *, P<0.05, t-test between two groups. Polyethylene glycol-modified PrRP31 exhibited significant anti-inflammatory activity.

[0033] Figure 4 The analgesic activity of polyethylene glycol-modified PrRP31 was evaluated using a mouse water bath tail-flick test. *, P<0.05, t-test between two groups. Polyethylene glycol-modified PrRP31 exhibited significant analgesic activity. Detailed Implementation

[0034] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0035] The technical solution adopted in this invention is: polyethylene glycol-modified PrRP31 exhibits significant anti-inflammatory and analgesic activity in a mouse paw edema inflammation model and a water bath tail-flick experiment. The molecular formula of the compound is C1. 166 H 263 N 57 O 45 S1, with a molecular weight of 3809.55, has the following structural formula:

[0036]

[0037] Its characteristics include the following steps:

[0038] The anti-inflammatory activity of carrageenan was evaluated using a mouse paw edema model. The principle is as follows: carrageenan, also known as styrax gum, is a commonly used and effective inflammatory agent both domestically and internationally. By using carrageenan-induced paw edema in mice as an experimental model, the degree of paw edema can be measured to detect the extent of inflammation and the effectiveness of anti-inflammatory drugs.

[0039] Inhibition rate = (Foot swelling value in the treatment group - Foot swelling value in the blank group) / (Foot swelling value in the blank group) × 100%

[0040] The analgesic activity of the drug in acute pain was detected using a mouse tail-flick test. First, the baseline pain threshold of the mice was determined, and mice whose tail flicking time was less than 3-5 seconds were culled. Then, intraperitoneal administration was performed, and the tail-flick pain threshold was measured. The measured pain threshold was converted to the maximum possible effect (MPE) using the following formula:

[0041] MPE (%) = (Pain threshold of treatment group - Baseline pain threshold) / (10 seconds - Baseline pain threshold) × 100%

[0042] The following examples refer to Figure 1-4 .

[0043] Example 1. Preparation of polyethylene glycolated PrRP31.

[0044] Condensation method: TBTU+DIEA, modified on the amino group of N-terminal Ser.

[0045] The embodiments of the present invention will now be described with reference to the accompanying drawings. Methods not specified with particular experimental conditions in the embodiments are generally performed according to the manufacturer's specifications or standard conditions.

[0046] The polyethylene glycol derivative of PrRP31 was prepared by solid-phase peptide synthesis, and the steps are as follows:

[0047] 1) Resin treatment

[0048] ① Resin swelling: Add starting resin (Rink-Amide-MBHA-Resin) to a 500ml reaction column, then immerse the resin in DCM, and finally dry it.

[0049] ② Deprotection: Add a DMF solution of piperidine (20% by volume), stir with N2 for 30 minutes, and filter off the solvent. Wash the resin 6 times with DMF and then dry it under vacuum.

[0050] 2) Amino acid coupling reaction

[0051] ① Dissolve 0.34g TBTU and protected amino acids in 0.27ml DMF in a beaker and stir thoroughly until completely dissolved.

[0052] ② Add the above reaction solution to the resin, then add DIEA, and purge with N2 for about 90 minutes.

[0053] ③ After the reaction is complete, remove the solvent and wash the resin three times with DMF.

[0054] ④ Add a 20% piperidine DMF solution to the resin and continue blowing N2 for 30 minutes.

[0055] ⑤ Then remove the solvent and wash the resin with DMF 6 times to complete the coupling of the amino acids.

[0056] ⑥ Repeat the above steps.

[0057] ⑦ After the last amino acid condensation is completed, the polypeptide is condensed, washed three times in sequence with DMF / DCM / methanol, dried, and weighed.

[0058] Finally, the following amino acid sequences are condensed sequentially from the C-terminal to the N-terminal residues.

[0059] PEG2-SRTHRHSMEIRTPD INPAWYASRGIRPVGRF-NH2

[0060] 3) TFA pyrolysis

[0061] ① First, add the resin to the prepared lysis solution of 86% TFA / 5% EDT / 5% phenyl sulfide / 3% phenol / 2% pure water and stir for 150 minutes.

[0062] ②Then the resin and lysis buffer are extracted, and ether is added to allow the polypeptide to be fully extracted.

[0063] ③ Next, the peptide was filtered using a Buchner funnel and washed thoroughly with ether 6 times to obtain crude peptide.

[0064] 4) Purification treatment

[0065] ① First, determine the peak time by analyzing the crude product (5-95%). Prepare the instrument in advance and equilibrate it.

[0066] ② Weigh an appropriate amount of the crude product and dissolve it in (acetonitrile + water), then clarify and filter it.

[0067] ③ Determine the preparation gradient based on the analysis of the crude product.

[0068] ④ Sample loading follows a gradient

[0069] ⑤ Peak collection to determine if the liquid molecular weight is correct.

[0070] ⑥ Analyzing liquids

[0071] ⑦ Transfer salt as required

[0072] ⑧ Add the liquid to the eggplant-shaped flask, remove the ACN from the rotary evaporator, and when the volume is reduced, place it on a plate and freeze dry for 3 days.

[0073] ⑨ Sample weighing, sending to a high-quality MS sample, reverse testing for high purity.

[0074] 5) Preparation of dry powder crude peptide product: Purification by high performance liquid chromatography to obtain pure PEGylated derivative of PrRP31, with the following structural formula:

[0075] Reference Figure 1 The high-performance liquid chromatography (HPLC) chromatogram of PrRP31-PEG showed that the purified sample had a purity of 98% and was free from interference from other impurities.

[0076] Reference Figure 2 The molecular weight of PrRP31-PEG by mass spectrometry was 3809.55, which is consistent with the theoretically calculated molecular weight, indicating that the identification of PrRP31-PEG was correct.

[0077] Example 2. Preparation of polyethylene glycolated PrRP31.

[0078] Condensation method: TBTU+DIEA, modified on the amino group of N-terminal Ser.

[0079] The embodiments of the present invention will now be described with reference to the accompanying drawings. Methods not specified with particular experimental conditions in the embodiments are generally performed according to the manufacturer's specifications or standard conditions.

[0080] The polyethylene glycol derivative of PrRP31 was prepared by solid-phase peptide synthesis, and the steps are as follows:

[0081] 1) Resin treatment

[0082] ① Resin swelling: Add starting resin (Rink-Amide-MBHA-Resin) to a 500ml reaction column, immerse the resin in DCM and allow it to swell fully, then dry the reagent under reduced pressure.

[0083] ② Deprotection: Add a DMF solution of piperidine (25% by volume), stir with N2 for 45 minutes, and filter off the solvent. Wash the resin three times with DMF and then dry it under vacuum.

[0084] 2) Amino acid coupling reaction

[0085] ① Dissolve 0.51g TBTU and the protected amino acid in 0.41ml DMF in a beaker and stir thoroughly until completely dissolved.

[0086] ② Add the above reaction solution to the resin, then add DIEA, and purge with N2 for about 70 minutes.

[0087] ③ After the reaction is complete, remove the solvent and wash the resin three times with DMF.

[0088] ④ Add a 30% piperidine DMF solution to the resin and continue blowing N2 for 70 minutes.

[0089] ⑤ Then remove the solvent and wash the resin three times with DMF to complete the coupling of the amino acids.

[0090] ⑥ Repeat the above steps.

[0091] ⑦ After the last amino acid condensation is completed, the peptide is condensed and washed 4 times in sequence with DMF / DCM / methanol. After drying, the weight is recorded.

[0092] Finally, the following amino acid sequences are condensed sequentially from the C-terminal to the N-terminal residues.

[0093] PEG2-SRTHRHSMEIRTPD INPAWYASRGIRPVGRF-NH2

[0094] 3) TFA pyrolysis

[0095] ① First, add the resin to the prepared lysis solution of 86% TFA / 5% EDT / 5% phenyl sulfide / 3% phenol / 2% pure water and stir for 120 minutes.

[0096] ②Then the resin and lysis buffer are extracted, and ether is added to allow the polypeptide to be fully extracted.

[0097] ③ Next, the peptide was filtered using a Buchner funnel and washed thoroughly with ether 6 times to obtain crude peptide.

[0098] 4) Purification treatment

[0099] ① First, determine the peak time by analyzing the crude product (5-95%). Prepare the instrument in advance and equilibrate it.

[0100] ② Weigh an appropriate amount of the crude product and dissolve it in (acetonitrile + water), then clarify and filter it.

[0101] ③ Determine the preparation gradient based on the analysis of the crude product.

[0102] ④ Sample loading follows a gradient

[0103] ⑤ Peak collection to determine if the liquid molecular weight is correct.

[0104] ⑥ Analyzing liquids

[0105] ⑦ Transfer salt as required

[0106] ⑧ Add the liquid to the eggplant-shaped flask, remove the ACN from the rotary evaporator, and when the volume is reduced, place it on a plate and freeze dry for 3 days.

[0107] ⑨ Sample weighing, sending to a high-quality MS sample, reverse testing for high purity.

[0108] 5) Preparation of dry powdered crude peptide product: Purification by high performance liquid chromatography to obtain pure polyethylene glycol derivative of PrRP31.

[0109] Example 3. Preparation of polyethylene glycolated PrRP31.

[0110] The polyethylene glycol derivative of PrRP31 was prepared by solid-phase peptide synthesis, and the steps are as follows:

[0111] 1) Resin pretreatment

[0112] ① Resin swelling: Rink-Amide-MBHA-Resin resin is stirred in dichloromethane, then immersed in DCM, and finally dried.

[0113] ② Deprotection: Add a 30% DMF solution of piperidine to the swollen and dried resin, stir with N2 for 45 minutes, and filter off the solvent. Wash the resin five times with DMF, then check and dry.

[0114] 2) Amino acid coupling reaction

[0115] ① Dissolve 0.44g TBTU and protected amino acids in 0.35ml DMF in a beaker, and stir thoroughly until completely dissolved to obtain a mixed solution.

[0116] ② Add the above reaction solution to the deprotected resin, then add DIEA, and purge with N2 for about 60 minutes.

[0117] ③ After the reaction is complete, remove the solvent and wash the resin repeatedly with DMF three times.

[0118] ④ Add a 30% piperidine DMF solution to the resin and continue blowing N2 for 45 minutes.

[0119] ⑤ Then remove the solvent and wash the resin 5 times with DMF to complete the coupling of the amino acids.

[0120] ⑥ Repeat the above steps.

[0121] ⑦ After the last amino acid condensation is completed, the polypeptide is condensed, washed three times in sequence with DMF / DCM / methanol, dried, and weighed.

[0122] Finally, the following amino acid sequences are condensed sequentially from the C-terminal to the N-terminal residues.

[0123] PEG2-SRTHRHSMEIRTPD INPAWYASRGIRPVGRF-NH2

[0124] 3) TFA pyrolysis

[0125] ① First, add the resin to the prepared lysis solution of 86% TFA / 5% EDT / 5% aniline sulfide / 3% phenol / 2% pure water and stir for 130 minutes.

[0126] ②Then the resin and lysis buffer are extracted, and ether is added to allow the polypeptide to be fully extracted.

[0127] ③ Next, the peptide was filtered using a Buchner funnel and washed thoroughly with ether five times to obtain crude peptide.

[0128] 4) Purification treatment

[0129] ① First, determine the peak time by analyzing the crude product (5-95%). Prepare the instrument in advance and equilibrate it.

[0130] ② Weigh an appropriate amount of the crude product and dissolve it in (acetonitrile + water), then clarify and filter it.

[0131] ③ Determine the preparation gradient based on the analysis of the crude product.

[0132] ④ Sample loading follows a gradient

[0133] ⑤ Peak collection to determine if the liquid molecular weight is correct.

[0134] ⑥ Analyzing liquids

[0135] ⑦ Transfer salt as required

[0136] ⑧ Add the liquid to the eggplant-shaped flask, remove the ACN from the rotary evaporator, and when the volume is reduced, place it on a plate and freeze dry for 3 days.

[0137] ⑨ Sample weighing, sending to a high-quality MS sample, reverse testing for high purity.

[0138] 5) Preparation of dry powder crude peptide product: Purification by high performance liquid chromatography to obtain pure PEGylated derivative of PrRP31, with the following structural formula:

[0139] Example 4. Evaluation of the anti-inflammatory activity of PrRP31-PEG using a mouse paw edema inflammation model.

[0140] 1) Laboratory animals: The laboratory mice are housed in an SPF-grade environment with a temperature of 20-26℃ and a humidity of 40%-60%, with a 12-hour day-night cycle. 5-6 mice are housed per cage, with free access to food and water.

[0141] 2) Experimental grouping: The experiment was divided into two groups: the Vehicle group and the 5mg / kg PrRP31-PEG group. The number of mice in each group was the same (10 mice / group).

[0142] 3) Mouse paw edema inflammation model:

[0143] ① Six- to eight-week-old healthy C57BL / 6 mice were randomly divided into a negative control group and a drug group.

[0144] ② Mice were intraperitoneally injected with 5 mg / kg PrRP31-PEG and physiological saline. 30 min after administration, 30 μl of 1% (w / v) carrageenan was injected into the plantar surface of the right hind paw of each mouse to induce inflammation. The thickness of the left and right paws of the mice was measured with calipers at 1, 2, 3, 4, 5, 6, and 24 hours after carrageenan injection.

[0145] Swelling thickness (mm) = Right foot thickness (mm) - Left foot thickness (mm).

[0146] Reference Figure 3 In a mouse paw edema inflammation model, PrRP31-PEG at 5 mg / kg inhibited inflammation by 37.09% (5 hours).

[0147] Example 5. Evaluation of the analgesic activity of PrRP31-PEG using a mouse water bath tail-flick test model.

[0148] 1) Laboratory animals: The laboratory mice are housed in an SPF-grade environment with a temperature of 20-26℃ and a humidity of 40%-60%, with a 12-hour day-night cycle. 5-6 mice are housed per cage, with free access to food and water.

[0149] 2) Experimental grouping: The experiment was divided into two groups: the Vehicle group and the 5mg / kg PrRP31-PEG group. The number of mice in each group was the same (10 mice / group).

[0150] 3) Mouse water bath tail-flicking experiment model:

[0151] ① Similarly, healthy C57BL / 6 mice aged 6-8 weeks were randomly divided into a negative control group and a drug group.

[0152] ② Before the experiment, the baseline pain threshold of the mice was first determined, and mice whose tail flicking time was not 3-5 seconds were eliminated. Then, the mice were injected intraperitoneally with 5 mg / kg PrRP31-PEG and physiological saline, respectively, and the tail flicking pain threshold was measured.

[0153] Reference Figure 4 In a mouse water bath tail-flick model, PrRP31-PEG at 5 mg / kg produced the maximum analgesic MPE% value.

[0154] The following specific examples further illustrate the application of polyethylene glycol-modified PrRP31 as the active ingredient in the preparation of anti-inflammatory and analgesic drugs.

[0155] Example 6. Preparation of tablets

[0156]

[0157] Process: 1000 tablets are prepared using conventional tablet preparation processes, each containing 35mg of PrRP31-PEG.

[0158] Dosage and administration: Take 1-2 tablets twice a day.

[0159] Example 7. Preparation of soft capsules

[0160]

[0161] Process: Prepare 1000 capsules using conventional capsule preparation process, each capsule containing 90mg of PrRP31-PEG.

[0162] Dosage and administration: Take 1-2 capsules twice a day.

[0163] Example 8. Preparation of Injection Solution

[0164]

[0165]

[0166] Process: Following the standard process for preparing injectables, a total of 1000 vials of 2ml each were produced, each containing 100mg of PrRP31-PEG.

[0167] Dosage and administration: Twice a day, 1 to 2 vials each time.

[0168] The fillers, disintegrants, binders, lubricants, and other excipients in the above embodiments are all the most common excipients in pharmaceutics.

Claims

1. A method for preparing polyethylene glycol-modified PrRP31, characterized by The steps are as follows: Step 1, resin swelling: add Rink-Amide-MBHA-Resin starting resin into the reaction column, then immerse in DCM for 20-30 min, and then extract the water in the reaction column; Step 2, deprotection: add piperidine DMF solution, stir for 20-30 min under N2, and filter dry solvent; then wash the resin with DMF for 6-8 times, and extract the water; Step 3: dissolve 0.34g TBTU and protected amino acid in a beaker with 0.27ml DMF, and stir well until completely dissolved; Step 4: add the reaction solution of step 3 to the resin, and then add DIEA, and blow N2 for 1-2 hours; Step 5: after the reaction is completed, remove the solvent, and wash the resin with DMF for 3-5 times; Step 6: add 20% piperidine DMF solution to the resin, and continue to blow N2 for 30-40 min; Step 7: then remove the solvent, and wash the resin with DMF for 6-8 times, and complete the coupling of the amino acid; Repeat steps 1-7, and each time replace the starting resin of step 1 with the material obtained in step 7, until the last amino acid is coupled in sequence from C to N terminal residues, and a polyethylene glycol modified PrRP31 is obtained in the resin of the reaction column, which is the following sequence of amino acids, i.e. polypeptide: PEG2-SRTHRHSMEIRTPDINPAWYASRGIRPVGRF-NH2; The polyethylene glycol modified PrRP31 obtained in the resin of the reaction column is first extracted with a cleavage solution to obtain a crude peptide, and then purified to obtain a fine purity polypeptide; The crude peptide is purified by adding the cleavage solution to the condensed reaction column resin, stirring for 2-3 hours, then separating the resin and the cleavage solution, adding ether to analyze the polypeptide in the reaction column resin, filtering and washing with ether for 6-8 times, and finally obtaining the crude peptide; The purification process is as follows: determine the main peak time by analyzing 5-95% of the crude product, dissolve in acetonitrile and water solution, clarify and filter; then extract according to the main peak time to obtain a liquid, which is added to a flask, and rotary evaporation is carried out for 3-4 days to obtain a fine purity polypeptide; PEG modified the amino terminal Ser of PrRP31, the molecular formula is C 166 H 263 N 57 O 45 S1, the structural formula is as follows: Where: C 166 H 263 N 57 O 45 S1 molecular weight is 3809.

55.

2. The method of claim 1, wherein: The volume fraction of the DMF solution in step 2 is 20%.

3. The method of using polyethylene glycol-modified PrRP31 prepared according to claim 1, wherein: The polyethylene glycol modified PrRP31 is used for preparing an anti-inflammatory analgesic drug. ​ 4. The method of claim 3, wherein: The polyethylene glycol modified PrRP31 is used for preparing 1000 tablets of tablets, and the formula is: polyethylene glycol modified PrRP31 45.0g, filler 170.0g, disintegrating agent 15.0g, adhesive 10.0g and lubricant 5.0g, which is prepared into tablets according to the conventional process of preparing tablets.

5. The method of claim 3, wherein: The polyethylene glycol modified PrRP31 is used for preparing 1000 soft capsules, and the formula is: polyethylene glycol modified PrRP31 90.0g, adhesive 10.0g, filler 80.0g and lubricant 20.0g, which is prepared according to the conventional process of preparing capsules.

6. The method of claim 3, wherein: The polyethylene glycol-modified PrRP31 is used for preparing injection 1 ml of injection 1000 pieces of formula: polyethylene glycol-modified PrRP31 100.0 g, citric acid 2.0 g, sodium citrate 1.0 g, sodium chloride 15.0 g and water for injection 2000 ml, according to the conventional process of preparing injection.

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