Kappa opioid receptor agonist and application thereof

Abstract

The invention discloses a kappa opioid receptor stimulant, and a stereoisomer and a pharmaceutically acceptable salt thereof, and belongs to the technical field of biological medicines, and the structure of the kappa opioid receptor stimulant is shown in the specification. The kappa opioid receptor agonist provided by the invention has high selectivity to a kappa opioid receptor, the activity of the kappa opioid receptor agonist is 3-15 times that of Difelikefalin, and the kappa opioid receptor agonist is high in pharmaceutical activity and can be used for treating, preventing and / or relieving pruritus and / or easing pain. D-Ph-AA1-AA2-D-Lys-4-aminopiperidine-4-carboxamide-AA3-AA4-AA5 (formula I) is shown in the description, and the structural formula of the D-Ph-AA1-AA2-D-Lys-4-aminopiperidine-4

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedicine, and in particular relates to an opioid peptide which is a highly selective κ receptor activator and an application thereof. Background Art

[0002] Opioids exert their physiological effects mainly by binding to the three known classical opioid receptors, μ, δ and κ. These three receptors are members of the G protein-coupled receptor family and are mainly distributed in the central nervous system and also exist in many peripheral tissues.

[0003] Among them, the most classic drug is morphine, which mainly exerts analgesic effects through the action of μ opioid receptors. Commonly used analgesics in clinical practice also include other μ opioid receptor drugs, such as traditional opioid drugs represented by dihydromorphone and fentanyl. However, μ opioid receptor drugs will produce a variety of side effects after long-term use, such as tolerance, dependence, respiratory depression, and effects on gastrointestinal motility, which not only increases the cost of treatment, but also affects the patient's recovery cycle. Some non-opioid injections, such as acetaminophen and nonsteroidal anti-inflammatory drugs, have poor analgesic effects, which limits their scope of use and dosage; in addition, there are certain side effects, such as acetaminophen increasing liver toxicity and nonsteroidal anti-inflammatory drugs causing various gastrointestinal diseases.

[0004] Kappa opioid receptors are present in the brain, spinal cord, central and peripheral nerve endings, somatic and visceral primary sensory afferent nerve cell bodies, and immune cells. Studies have found that the use of kappa opioid receptor agonists can target kappa opioid receptors for intervention to treat pain and prevent a wide variety of diseases and conditions, such as for the treatment of pain including hyperalgesia, in ocular disorders and ocular pain, in the treatment of uremia and opioid-induced pruritus, etc.

[0005] Difelikefalin (trade name KORSUVA) is a first-in-class highly selective kappa opioid receptor (KOR) full agonist that can inhibit the activity of itch-producing peripheral neurons and has no significant activity on other receptors (including μ or δ opioid receptors), ion channels or transporters. In addition, unlike small molecule KOR agonists, Korsuva is a small synthetic peptide that mainly activates KORs expressed by peripheral neurons (PNS) and immune cells. The US FDA has approved Difelikefalin for the treatment of moderate to severe pruritus associated with chronic kidney disease (CKD-aP) in adults receiving hemodialysis (HD). Difelikefalin has shown anti-itch and analgesic properties in multiple different Phase II or Phase III studies, as well as inhibition of acute postoperative pain (IV preparations in laparoscopic hysterectomy, ventral hernia and bunionectomy).

[0006] The purpose of the present invention is to discover a new highly active kappa opioid receptor agonist. Summary of the invention

[0007] One object of the present invention is to provide a class of peptide compounds, which are highly selective for κ opioid receptors and are new highly active κ opioid receptor agonists; another object of the present invention is to provide a pharmaceutical composition; and yet another object of the present invention is to provide a use of the compound and the pharmaceutical composition.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a κ opioid receptor agonist having Formula I, and stereoisomers and pharmaceutically acceptable salts thereof:

[0010] D-Phe-AA1-AA2-D-Lys-4-aminopiperidine-4-carboxamide-AA3-AA4-AA5

[0011] (Formula I)

[0012] in:

[0013] AA1 is modified or unmodified D-Phe, or modified or unmodified D-Tyr;

[0014] AA2 is D-Leu, or D-cyclopropylalanine;

[0015] AA3 is -(PEG m1 (CH2) m2 CO) m3 -, or (AA6) m4 ,in:

[0016] m1 is an integer from 1 to 10;

[0017] m2 is an integer from 1 to 5;

[0018] m3 is an integer from 1 to 5;

[0019] m4 is an integer from 1 to 5;

[0020] AA6 is AEEA, or Gly, or D- or L-form Ala, or D- or L-form Leu, or D- or L-form Phe, or D- or L-form Ser, or D- or L-form Thr, or D- or L-form Tyr, or D- or L-form Asp, or D- or L-form Glu, or D- or L-form Gln, or D- or L-form Lys, or D- or L-form Arg, or D- or L-form His;

[0021] AA4 is (AA7)n ,in:

[0022] n is an integer from 1 to 10;

[0023] AA7 is structural formula I wherein AA3 is D-type Ala, or D-type Arg, or D-type Asp, or D-type Asn, or D-type Glu, or D-type Gln, or D-type His, or D-type Ile, or D-type Leu, or D-type Met, or D-type Phe, or D-type Pro, or D-type Ser, or D-type Thr, or D-type Tyr, or D-type Trp, or D-type Val;

[0024] AA5 is OH or NH2.

[0025] Preferably, AA1 is a modified D-Phe, and the modified D-Phe is selected from D-Phe(2-F), D-Phe(4-F), D-Phe(2-Cl), D-Phe(4-Cl), D-Phe(2-Br), D-Phe(4-Br), D-Phe(2-I), D-Phe(4-I), D-Phe(4-Me), D-Phe(4-Et), D-Phe(4-Ipr), D-Phe(4-NH2), D-Phe(4-NHCH3), D-Phe(4-NHCH2CH3), D-Phe(4-NHCH(CH3)2), D-Phe(4-N(CH3)2) or D-Phe(4-N(CH3)CH2CH3).

[0026] Preferably, AA1 is a modified D-Tyr, wherein the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et), D-Tyr(CH2CF3) or D-Tyr(Ipr).

[0027] Furthermore, the κ opioid receptor agonist has a structure shown in Formula II, and its stereoisomers and pharmaceutically acceptable salts:

[0028] D-Phe-AA1-AA2-D-Lys-4-aminopiperidine-4-carboxamide-R-(AA8) p -NH2(OH)

[0029] (Formula II)

[0030] Unless otherwise specified, "-NH2(OH)" in the general structural formula of the present invention represents -NH2 or -OH.

[0031] Wherein, AA1 is modified D-Phe, or is modified D-Tyr, and the specific modification method is as described above;

[0032] AA2 is D-Leu, or D-cyclopropylalanine;

[0033] R is present or absent. When R is present, R is selected from -PEG m1 CH2CO-、-AEEA n1 -or-Gly n2 -;in:

[0034] m1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0035] n1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0036] n2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0037] AA8 is Lys, or D-Lys, and p is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p is 0, it means that AA8 does not exist.

[0038] In an optional embodiment of the present invention, the κ opioid receptor agonist has a structure shown in Formula III, and stereoisomers and pharmaceutically acceptable salts thereof:

[0039] D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-R1-(AA8) p1 -NH2(OH)

[0040] (Formula III)

[0041] Wherein, D-Tyr(X) represents a modified D-Tyr, and the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et), D-Tyr(CH2CF3) or D-Tyr(Ipr).

[0042] R1 is present or absent. When R1 is present, R1 is selected from -PEG k1 CH2CO- or -Gly n2 -;in:

[0043] k1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0044] n2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0045] AA8 is Lys or D-Lys, and p1 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p1 is 0, it means that AA8 does not exist.

[0046] In an optional embodiment of the present invention, the κ opioid receptor agonist has a structure shown in Formula IV, and stereoisomers and pharmaceutically acceptable salts thereof:

[0047] D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-R2-(AA8) p2 -NH2(OH)

[0048] (Formula IV)

[0049] Wherein, D-Tyr(X) represents a modified D-Tyr, and the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et) or D-Tyr(Ipr).

[0050] R2 is present or absent. When R2 is present, R2 is -PEG k2 CH2CO-; among which:

[0051] k2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5;

[0052] In the most preferred embodiment of the present invention, k2 is 1, 2, or 3;

[0053] AA8 is Lys, or D-Lys, and p2 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p2 is 0, it indicates that AA8 does not exist;

[0054] In the most preferred embodiment of the present invention, p2 is 0 or 1.

[0055] In an optional embodiment of the present invention, the κ opioid receptor agonist has a structure as shown in Formula V, and stereoisomers and pharmaceutically acceptable salts thereof:

[0056] D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-(AA8) p3 -NH2(OH)

[0057] (Formula V)

[0058] Wherein, D-Phe(X) represents modified D-Phe, and the modified D-Phe is selected from D-Phe(2-F), D-Phe(4-F), D-Phe(2-Cl), D-Phe(4-Cl), D-Phe(2-Br), D-Phe(4-Br), D-Phe(2-I), D-Phe(4-I), D-Phe(4-Me), D-Phe(4-Et), D-Phe(4-Ipr), and D-Phe(4-NH2).

[0059] AA8 is Lys, or D-Lys, and p3 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p3 is 0, it indicates that AA8 does not exist;

[0060] In the most preferred embodiment of the present invention, p3 is 0 or 1.

[0061] Further preferably, the structural formula of the κ opioid receptor agonist is selected from one or more of 1)-10):

[0062] 1) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxylic acid-NH2(OH)

[0063] 2) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH)

[0064] 3) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-(AA8) q -NH2(OH)

[0065] 4) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-PEG k1 CH2CO-AA8-NH2(OH)

[0066] 5) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-Gly n2 -AA8-NH2(OH)

[0067] 6) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH)

[0068] 7) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-AA8-NH2(OH)

[0069] 8) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-PEG k2 CH2CO-AA8-NH2(OH)

[0070] 9) D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH)

[0071] 10) D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-AA8-NH2(OH)

[0072] In the above structural formula, AA8 is Lys, or D-Lys; wherein,

[0073] In formula 1), D-Tyr(X) is D-Tyr(Et);

[0074] In formula 2)-3), D-Tyr(X) is D-Tyr(Me), or D-Tyr(Et), or D-Tyr(CH2CF3), or D-Tyr(Ipr), q is 1, or 2, or 3, or 4, or 5, or 6;

[0075] In formulas 4) to 8), D-Tyr(X) is D-Tyr(Et),

[0076] k1 is 1, 2, 3, 4, or 5;

[0077] n2 is 1, 2, 3, 4, or 5;

[0078] k2 is 1, 2, or 3;

[0079] In formula 9), D-Phe(X) is D-Phe(4-F), or D-Phe(4-Cl), or D-Phe(4-Br), or D-Phe(4-I);

[0080] In formula 10), D-Phe (X) is D-Phe (4-F), or D-Phe (4-Cl), or D-Phe (4-Br), or D-Phe (4-I), or D-Phe (4-Me), or D-Phe (4-Et), or D-Phe (4-Ipr), or D-Phe (4-NH2);

[0081] In a second aspect, the present invention provides a pharmaceutical composition, comprising the κ opioid receptor agonist provided by the present invention, and stereoisomers and pharmaceutically acceptable salts thereof.

[0082] Furthermore, the pharmaceutical composition also includes a pharmaceutically acceptable carrier.

[0083] In a third aspect, the present invention provides a κ opioid receptor agonist, and its stereoisomers and pharmaceutically acceptable salts, and / or the use of the pharmaceutical composition in the preparation of drugs for preventing and / or relieving itching and / or analgesia.

[0084] The kappa opioid receptor agonist provided by the present invention is highly selective for kappa opioid receptors, and its activity is 3-15 times that of the currently marketed drug Difelikefalin. It has high drug activity and can be used for treating, preventing and / or relieving itching and / or analgesia. DETAILED DESCRIPTION

[0085] The term "stereoisomer" in the present invention refers to compounds with the same chemical structure but different arrangements of atoms or groups in space. Stereoisomers include enantiomers, diastereomers, conformers (rotamers), geometric isomers (cis / trans) isomers, atropisomers, etc.

[0086] The "pharmaceutical composition" of the present invention may refer to a composition used for the treatment of a disease or for in vitro cell culture experiments. When used for the treatment of a disease, the term "pharmaceutical composition" generally refers to a unit dosage form and may be prepared by any of the methods well known in the pharmaceutical field. All methods include the step of combining the active ingredient with an excipient that constitutes one or more accessory ingredients.

[0087] The term "pharmaceutically acceptable" in the present invention means that the substance or composition must be chemically and / or toxicologically compatible with the other ingredients of the formulation and / or the mammals treated therewith. Preferably, the "pharmaceutically acceptable" in the present invention refers to those approved by federal regulatory agencies or national governments or listed in the United States Pharmacopoeia or other generally recognized pharmacopeias for use in animals, especially humans.

[0088] Specifically, the term "pharmaceutically acceptable excipient" may include any solvent, solid excipient, diluent or other liquid excipient, etc., suitable for a specific target dosage form. Except for any conventional excipients that are incompatible with the κ opioid receptor agonist provided by the present invention, such as any adverse biological effects produced or interactions with any other components in the pharmaceutically acceptable composition in a harmful manner, their use is also within the scope of consideration of the present disclosure.

[0089] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, not all. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0090] The terms "alleviate", "improve" or "mitigate" in the present invention are used interchangeably herein. These terms refer to a means of obtaining a beneficial or desired result, including but not limited to a therapeutic benefit. "Therapeutic benefit" means eradication or amelioration of the underlying disorder being treated. Here, a therapeutic benefit is obtained by eradication or amelioration of one or more physiological symptoms associated with the underlying disorder, such that an improvement is observed in the subject, although the subject may still be afflicted with the underlying disorder.

[0091] The present invention discloses a κ opioid receptor agonist and its use. Those skilled in the art can refer to the content of this article and appropriately improve the relevant parameters to achieve it. The method of the present invention has been described through preferred embodiments. It is obvious that relevant personnel can modify or appropriately change and combine the compounds and preparation methods described herein without departing from the content, spirit and scope of the present invention to achieve and apply the technology of the present invention.

[0092] The Chinese names corresponding to the English abbreviations involved in the present invention are shown in the following table:

[0093]

[0094]

[0095] Example 1 Preparation of Compounds

[0096] The preparation method is a peptide solid phase synthesis method, including: preparing a peptide resin by a solid phase peptide synthesis method, the peptide resin is then subjected to acid hydrolysis to obtain a crude product, and finally the crude product is purified to obtain a pure product; wherein the step of preparing the peptide resin by the solid phase peptide synthesis method is to sequentially connect the corresponding protected amino acids in the following sequence to the carrier resin by a solid phase coupling synthesis method to prepare the peptide resin:

[0097] In the above preparation method, the amount of the Fmoc-protected amino acid is 1.2 to 6 times the total molar number of the resin fed, preferably 2.5 to 3.5 times.

[0098] In the above preparation method, the substitution value of the carrier resin is 0.3-1.5 mmol / g resin, and the preferred substitution value is 0.6-1.0 mmol / g resin.

[0099] As a preferred embodiment of the present invention, the solid phase coupling synthesis method is: the protected amino acid-resin obtained in the previous step is deprotected from the Fmoc protecting group and then coupled with the next protected amino acid. The deprotection time of the Fmoc deprotection is 10 to 60 minutes, preferably 15 to 25 minutes. The coupling reaction time is 60 to 300 minutes, preferably 100 to 140 minutes.

[0100] The coupling reaction requires the addition of a condensation reagent, which is selected from DIC (N,N-diisopropylcarbodiimide), N,N-dicyclohexylcarbodiimide, benzotriazole-1-yl-oxytripyrrolidinophosphine hexafluorophosphate, 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate or O-benzotriazole-N,N,N',N'-tetramethyluronium tetrafluoroborate; preferably N,N-diisopropylcarbodiimide. The molar amount of the condensation reagent is 1.2 to 6 times the total molar number of amino groups in the amino resin, preferably 2.5 to 3.5 times.

[0101] The coupling reaction requires the addition of an activation reagent, which is selected from 1-hydroxybenzotriazole or N-hydroxy-7-azabenzotriazole, preferably 1-hydroxybenzotriazole. The amount of the activation reagent is 1.2 to 6 times the total molar number of amino groups in the amino resin, preferably 2.5 to 3.5 times.

[0102] As a preferred solution of the present invention, the Fmoc-removing reagent is a PIP / DMF (piperidine / N,N-dimethylformamide) mixed solution, wherein the piperidine content in the mixed solution is 10-30% (V). The amount of the Fmoc-removing reagent is 5-15 mL per gram of amino resin, preferably 8-12 mL per gram of amino resin.

[0103] Preferably, the peptide resin is subjected to acid hydrolysis to simultaneously remove the resin and the side chain protecting groups to obtain a crude product:

[0104] Further preferably, the acid hydrolysis agent used in the acid hydrolysis of the peptide resin is a mixed solvent of trifluoroacetic acid (TFA), 1,2-ethanedithiol (EDT) and water, and the volume ratio of the mixed solvent is: TFA is 80-95%, EDT is 1-10%, and the balance is water.

[0105] More preferably, the volume ratio of the mixed solvent is: 89-91% TFA, 4-6% EDT, and the balance is water. Optimally, the volume ratio of the mixed solvent is: 90% TFA, 5% EDT, and the balance is water.

[0106] The amount of the acid hydrolysis agent is 4 to 15 mL per gram of peptide resin; preferably, 7 to 10 mL per gram of peptide resin.

[0107] The acid hydrolysis agent is used for 1 to 6 hours at room temperature, preferably 3 to 4 hours.

[0108] Furthermore, the crude product was purified by high performance liquid chromatography and freeze-dried to obtain a pure product.

[0109] 1. Synthesis of peptide resin

[0110] Take the carrier resin, remove the Fmoc protection and couple the reaction, and sequentially connect the corresponding protected amino acids in the sequence to obtain the peptide resin:

[0111] (1) Insertion of the first protected amino acid in the main chain

[0112] Take 0.03 mol of the first protected amino acid and 0.03 mol of HOBt, dissolve them in an appropriate amount of DMF; take another 0.03 mol of DIC, slowly add it to the protected amino acid DMF solution under stirring, and stir the reaction at room temperature for 30 minutes to obtain an activated protected amino acid solution for use.

[0113] Take 0.01 mol of the carrier resin (substitution value is about 0.4 mmol / g), use 20% PIP / DMF solution to deprotect for 25 minutes, wash and filter to obtain the Fmoc-free resin.

[0114] The activated first protected amino acid solution is added to the Fmoc-free resin, and the coupling reaction is carried out for 60 to 300 minutes. The resin containing one protected amino acid is filtered and washed to obtain.

[0115] (2) Accession of other protected amino acids

[0116] The same method as the first protected amino acid in the above-mentioned insertion sequence is used to sequentially insert the other corresponding protected amino acids in the above-mentioned series to obtain a peptide-containing resin.

[0117] 2. Preparation of crude product

[0118] Take the above peptide resin, add a cleavage reagent with a volume ratio of TFA: water: EDT = 95:5:5 (cleavage reagent 10 mL / g resin), stir evenly, and react at room temperature for 3 hours. The reaction mixture is filtered using a sand core funnel, and the filtrate is collected. The resin is washed 3 times with a small amount of TFA, and the filtrate is combined and concentrated under reduced pressure. Anhydrous ether is added to precipitate, and the precipitate is washed 3 times with anhydrous ether and dried to obtain an off-white powder.

[0119] 3. Preparation of pure product

[0120] Take the above crude concentrate, filter it with a 0.45 μm mixed microporous filter membrane, and purify it for later use;

[0121] The purification was carried out by high performance liquid chromatography, the chromatographic filler for purification was 10 μm reverse phase C18, the mobile phase system was 0.1% TFA / water solution-0.1% TFA / acetonitrile solution, the flow rate of the 30 mm*250 mm chromatographic column was 20 mL / min, the gradient system was used for elution, and the cyclic injection purification was carried out. The crude product solution was loaded on the chromatographic column, the mobile phase elution was started, the main peak was collected and the acetonitrile was evaporated to obtain the purified intermediate concentrate;

[0122] The purified intermediate concentrate is filtered through a 0.45 μm filter membrane for standby use, and the salt is exchanged by high performance liquid chromatography, the mobile phase system is 1% acetic acid / water solution-acetonitrile, the chromatographic filler for purification is 10 μm reverse phase C18, and the flow rate of the 30 mm*250 mm chromatographic column is 20 mL / min (the corresponding flow rate can be adjusted according to the chromatographic columns of different specifications); the gradient elution and the circular loading method are adopted, the sample is loaded into the chromatographic column, the mobile phase elution is started, the spectrum is collected, the change of the absorbance is observed, the main peak of the salt exchange is collected and the purity is detected by the analytical liquid phase, the main peak solution of the salt exchange is combined, and it is concentrated under reduced pressure to obtain a pure acetic acid aqueous solution, and freeze-dried to obtain a pure product.

[0123] The following compounds were synthesized using the above method:

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] Example 2 Determination of κ receptor agonist activity

[0131] 1. Determination method

[0132] Under the stimulation of Gi-coupled human kappa opioid receptor (OPRK1) and its specific opioid receptor agonist, it can inhibit the intracellular adenylate cyclase pathway and reduce the cAMP level. Forskolin can stimulate the release of cAMP in opioid receptor-high-expressing cell lines. By stimulating cell lines stably transfected with opioid receptors, the inhibitory effect of the test substance on the forskolin-stimulated cAMP release can be detected, and the activity of the test substance can be determined. The relative light unit (RLU) after each dose of cell stimulation is measured by homogeneous time-resolved fluorescence technology (HTRF), and then the EC of the agonist is calculated. 50 This activity determination method is currently a commonly used method for detecting the activity of opioid receptor agonists at home and abroad.

[0133] The CHO-K1 cell line stably expressing opioid receptors was used to stimulate the stably transfected cells with different concentrations of agonists (under the stimulation of a certain concentration of forskolin). The EC of the agonist was calculated by measuring the relative light units after each dose of stimulation. 50 value.

[0134] 2. Measurement results

[0135] The measurement results are shown in the following table:

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143] The above test results show that the activity of the compounds provided by the present invention is much greater than that of Difelikefalin, and the activity of compounds 1-142 provided in the examples is 3-15 times that of Difelikefalin.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A kappa opioid receptor agonist having formula I, and stereoisomers and pharmaceutically acceptable salts thereof: D-Phe-AA1-AA2-D-Lys-4-aminopiperidine-4-carboxamide-AA3-AA4-AA5 (Formula I) in: AA1 is modified or unmodified D-Phe, or modified or unmodified D-Tyr; AA2 is D-Leu, or D-cyclopropylalanine; AA3 is -(PEG m1 (CH2) m2 CO) m3 -, or (AA6) m4 ,in: m1 is an integer from 1 to 10; m2 is an integer from 1 to 5; m3 is an integer from 1 to 5; m4 is an integer from 1 to 5; AA6 is AEEA, or Gly, or D- or L-type Ala, or D- or L-type Leu, or D-type or L-type Phe, or D-type or L-type Ser, or D-type or L-type Thr, or is D-form or L-form Tyr, or is D-form or L-form Asp, or is D-form or L-form Glu, or is D-form or L-form Gln, or is D-form or L-form Lys, or is D-form or L-form Arg, or is D-form or L-form His; AA4 is (AA7) n ,in: n is an integer from 1 to 10; AA7 is structural formula I wherein AA3 is D-type Ala, or D-type Arg, or D-type Asp, or D-type Asn, or D-type Glu, or D-type Gln, or D-type His, or D-type Ile, or D-type Leu, or D-type Met, or D-type Phe, or D-type Pro, or D-type Ser, or D-type Thr, or D-type Tyr, or D-type Trp, or D-type Val; AA5 is OH or NH2.

2. The κ opioid receptor agonist according to claim 1, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: AA1 is a modified D-Phe, or a modified D-Tyr; the modified D-Phe is selected from D-Phe (2-F), D-Phe (4-F), D-Phe (2-Cl), D-Phe (4-Cl), D-Phe (2-Br), D-Phe (4-Br), D-Phe (2-I), D-Phe (4-I), D-Phe (4-Me), D-Phe (4-Et), D-Phe e(4-Ipr), D-Phe(4-NH2), D-Phe(4-NHCH3), D-Phe(4-NHCH2CH3), D-Phe(4-NHCH(CH3)2), D-Phe(4-N(CH3)2) or D-Phe(4-N(CH3)CH2CH3); the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et) or D-Tyr(Ipr).

3. The κ opioid receptor agonist according to claim 2, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: The κ opioid receptor agonist has a structure shown in Formula II: D-Phe-AA1-AA2-D-Lys-4-aminopiperidine-4-carboxamide-R-(AA8) p -NH2(OH) (Formula II) Wherein, AA1 is modified D-Phe, or is modified D-Tyr; AA2 is D-Leu, or D-cyclopropylalanine; R is present or absent. When R is present, R is selected from -PEG m1 CH2CO-、-AEEA n1 -or-Gly n2 -;in: m1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; n1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; n2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; AA8 is Lys, or D-Lys, and p is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p is 0, it means that AA8 does not exist.

4. The κ opioid receptor agonist according to claim 3, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: The κ opioid receptor agonist has a structure shown in Formula III: D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-R1-(AA8) p1 -NH2(OH) (Formula III) Wherein, D-Tyr(X) represents a modified D-Tyr, and the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et), D-Tyr(CH2CF3) or D-Tyr(Ipr); R1 is present or absent. When R1 is present, R1 is selected from -PEG k1 CH2CO- or -Gly n2 -;in: k1 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; n2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; AA8 is Lys or D-Lys, and p1 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p1 is 0, it means that AA8 does not exist.

5. The κ opioid receptor agonist according to claim 3, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: The κ opioid receptor agonist has a structure shown in Formula IV: D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-R2-(AA8) p2 -NH2(OH) (Formula IV) Wherein, D-Tyr(X) represents a modified D-Tyr, and the modified D-Tyr is selected from D-Tyr(Me), D-Tyr(Et) or D-Tyr(Ipr). R2 is present or absent. When R2 is present, R2 is -PEG k2 CH2CO-; among which: k2 is an integer between 1 and 5, specifically selected from 1, 2, 3, 4, and 5; In the most preferred embodiment of the present invention, k2 is 1, 2, or 3; AA8 is Lys, or D-Lys, and p2 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p2 is 0, it means that AA8 does not exist.

6. The κ opioid receptor agonist according to claim 3, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: The κ opioid receptor agonist has a structure shown in Formula V: D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-(AA8) p3 -NH2(OH) (Formula V) Wherein, D-Phe(X) represents a modified D-Phe, and the modified D-Phe is selected from D-Phe(2-F), D-Phe(4-F), D-Phe(2-Cl), D-Phe(4-Cl), D-Phe(2-Br), D-Phe(4-Br), D-Phe(2-I), D-Phe(4-I), D-Phe(4-Me), D-Phe(4-Et), D-Phe(4-Ipr), and D-Phe(4-NH2); AA8 is Lys, or D-Lys, and p3 is an integer between 0 and 6, specifically selected from 0, 1, 2, 3, 4, 5, and 6; when p3 is 0, it means that AA8 does not exist.

7. The κ opioid receptor agonist according to any one of claims 1 to 6, and its stereoisomers and pharmaceutically acceptable salts, characterized in that: The structural formula of the κ opioid receptor agonist is selected from one or more of 1) to 10): 1) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxylic acid-NH2(OH) 2) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH) 3) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-(AA8) q -NH2(OH) 4) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-PEG k1 CH2CO-AA8-NH2(OH) 5) D-Phe-D-Tyr(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-Gly n2 -AA8-NH2(OH) 6) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH) 7) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-AA8-NH2(OH) 8) D-Phe-D-Tyr(X)-D-cyclopropylalanine-D-Lys-4-aminopiperidine-4-carboxamide-PEG k2 CH2CO-AA8-NH2(OH) 9) D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-NH2(OH) 10) D-Phe-D-Phe(X)-D-Leu-D-Lys-4-aminopiperidine-4-carboxamide-AA8-NH2(OH) In the above structural formula, AA8 is Lys, or D-Lys; wherein, In formula 1), D-Tyr(X) is D-Tyr(Et); In formula 2)-3), D-Tyr(X) is D-Tyr(Me), or D-Tyr(Et), or D-Tyr(CH2CF3), or D-Tyr(Ipr), q is 1, or 2, or 3, or 4, or 5, or 6; In formulas 4) to 8), D-Tyr(X) is D-Tyr(Et), k1 is 1, 2, 3, 4, or 5; n2 is 1, 2, 3, 4, or 5; k2 is 1, 2, or 3; In formula 9), D-Phe(X) is D-Phe(4-F), or D-Phe(4-Cl), or D-Phe(4-Br), or D-Phe(4-I); In formula 10), D-Phe (X) is D-Phe (4-F), or D-Phe (4-Cl), or D-Phe (4-Br), or D-Phe (4-I), or D-Phe (4-Me), or D-Phe (4-Et), or D-Phe (4-Ipr), or D-Phe (4-NH2).

8. A pharmaceutical composition, characterized in that The pharmaceutical composition comprises the κ opioid receptor agonist according to any one of claims 1 to 7, and its stereoisomers and pharmaceutically acceptable salts.

9. The pharmaceutical composition according to claim 8, characterized in that The pharmaceutical composition also includes a pharmaceutically acceptable carrier.

10. Use of the κ opioid receptor agonist according to any one of claims 1 to 7, its stereoisomers and pharmaceutically acceptable salts, and / or the pharmaceutical composition according to any one of claims 8 to 9 in the preparation of drugs for preventing and / or relieving itching and / or analgesia.

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