WO2021038431A1 - An improved process for the preparation of etelcalcetide hydrochloride - Google Patents

An improved process for the preparation of etelcalcetide hydrochloride Download PDF

Info

Publication number
WO2021038431A1
WO2021038431A1 PCT/IB2020/057916 IB2020057916W WO2021038431A1 WO 2021038431 A1 WO2021038431 A1 WO 2021038431A1 IB 2020057916 W IB2020057916 W IB 2020057916W WO 2021038431 A1 WO2021038431 A1 WO 2021038431A1
Authority
WO
WIPO (PCT)
Prior art keywords
arg
formula
ala
etelcalcetide
cys
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IB2020/057916
Other languages
French (fr)
Inventor
Shafee Mohammed Abdul
Deshmukh BHARTI
Vivekananda Reddy GOLI
Riyaz SHAIK
Narayan Ratan THOMBARE
Nagana Goud Agasaladinni
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Auro Peptides Ltd
Original Assignee
Auro Peptides Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Auro Peptides Ltd filed Critical Auro Peptides Ltd
Priority to EP20857261.0A priority Critical patent/EP4021920A4/en
Priority to US17/638,181 priority patent/US20220298206A1/en
Publication of WO2021038431A1 publication Critical patent/WO2021038431A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P5/00—Drugs for disorders of the endocrine system
    • A61P5/18—Drugs for disorders of the endocrine system of the parathyroid hormones
    • A61P5/20—Drugs for disorders of the endocrine system of the parathyroid hormones for decreasing, blocking or antagonising the activity of PTH
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/04—Linear peptides containing only normal peptide links
    • C07K7/06—Linear peptides containing only normal peptide links having 5 to 11 amino acids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P5/00—Drugs for disorders of the endocrine system
    • A61P5/18—Drugs for disorders of the endocrine system of the parathyroid hormones

Definitions

  • the present invention relates to an improved process for the preparation of Etelcalcetide hydrochloride of Formula (I). tys-OH
  • Etelcalcetide is a synthetic peptide calcium-sensing receptor agonist.
  • Etelcalcetide is 8 amino acid peptide with the following Chemical name: N-acetyl-D-cysteinyl- S-(L-cysteine disulfide)-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D- argininamide and this can be structurally represented as follows: This drug was approved as its hydrochloride salt.
  • the Etelcalcetide hydrochloride of Formula (I) is shown below: tys-OH
  • Etelcalcetide is approved in the United States under the trade name PARSABIV ® for the treatment of Secondary hyperparathyroidism (HPT) in adult patients with chronic kidney disease (CKD) on hemodialysis.
  • PARSABIV ® Primary hyperparathyroidism
  • CKD chronic kidney disease
  • Etelcalcetide is first described in US patent US 8,377,880.
  • the US ’880 patent discloses a process to prepare peptides and conjugates by solid-phase chemistry at 0.25 mmol scale on an ABI automated synthesizer. Sequential coupling of Fmoc- amino acids (4 eq, Anaspec) to Rink-amide resin (Novabiochem) was accomplished using HBTU/DIEA activation. The assembled peptide was cleaved with a TFA cocktail (phenol (5%), triisopropylsilane (2.5%) and water (2.5%); 10 mL per gram of resin) and isolated by precipitation with diethyl ether. After purification using Cl 8 HPLC the final product was isolated in the TFA salt form by lyophilization of appropriate fractions and characterized by HPFC (>95% purity) and EC -MS (confirmed MW).
  • US Patent application US 2017/0190739 involves conversion of Etelcalcetide TFA salt to Etelcalcetide hydrochloride salt by the addition of 12M aqueous hydrochloric acid. Use of such a high concentrated hydrochloric acid may hydrolyze the peptide resulting in formation of undesired impurities.
  • Patent application US 2018/0079777 & Chinese Patent application CN 107434820 uses Iodine, dimethyl sulfoxide & hydrogen peroxide, a conventional method of disulphide bond formation leads to the formation of Etelcalcetide dimers, Cystine and other linear impurities.
  • the main objective of the present invention is to provide an improved process for the preparation of Etelcalcetide hydrochloride of Formula (I) by using novel compounds of formula (IV) and (V).
  • Formula (V) Another objective of the present invention is to provide purification of solution of compound of formula (V) by concentrating the solution using Nano filtration with membrane.
  • the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I),
  • Formula (I) which comprises: a) Global de-protecting of compound of Formula (II) to form compound of Formula (III);
  • X is H, side chain protecting groups; b) Reacting compound of Formula (III) with methoxycarbonylsulfenyl chloride (Scm) to form crude compound of Formula (IV);
  • the present invention provides a process for preparing Etelcalcetide acetate of Formula (VI), which comprises purifying crude compound of Formula (IV) to form compound of Formula (V), followed by concentrating solution containing compound of Formula (V) by Nano filtration using membrane and contacted with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI).
  • the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I);
  • Formula (I) which comprises; a) Reacting linear peptide of Formula (Ilia)
  • Etelcalcetide b) Purifying crude Etelcalcetide on preparative HPLC, followed by salt exchange to obtain Etelcalcetide hydrochloride of Formula (I).
  • the present invention relates to a process for the preparation of Etelcalcetide Hydrochloride.
  • the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I);
  • Formula (I) which comprises: a) Global de-protecting of compound of Formula (II) to form a compound of Formula (III);
  • the side chain protecting groups (X) used in step a) is selected from the group consisting of acetamidomethyl (Acm), trityl (Trt), benzyl (Bzl), tert-butyl (tBu), tert-butylthio (tButhio), p-methoxybenzyl (pMeoBzl), Phenylacetamidomethyl (Phacm), 4-methyltrityl (Mtt) and 4-methoxytrityl (Mmt).
  • TFA:TIPS:DTT:solvcnt or) TFA TIPS DTT: water: solvent (or) TFA :TIS: solvent.
  • the solvent is comprising water, dimethyl sulfide, methanol, ethanol, 1-propanaol, isopropanol, n-butanol, dichloromethane, dichloroethane, chlorobenzene, diethyl ester, tetrahydrofuran, diisopropyl ether or mixture thereof.
  • Linear peptide compound of Formula (III) reacts with Methoxycarbonylsulfenyl chloride (Scm) in the presence of trifluoroacetic acid followed by isolating crude peptide compound of formula (IV) by precipitating with pre-cool MTBE, followed by dried under vacuum.
  • purifying crude compound of Formula (IV) on preparative HPFC is performed with buffer system comprising 0.5% acetic acid as buffer A and 100% acetonitrile as buffer B to form compound of Formula (V) and subjecting the solution of compound of Formula (V) to Nano filtration using 300 D molecular weight cut-off membrane and concentration up to l/5 th volume (from original volume) and added equal amount of water to the retentate and concentrate of 20 grams/Fiter as final concentration.
  • the concentrated solution is contacted with F- cysteine to obtain Etelcalcetide acetate of Formula (VI).
  • F-cysteine is selected from F-cysteine hydrochloride and F-cysteine hydrochloride monohydrate.
  • Etelcalcetide acetate of Formula (VI) is loaded on preparative HPFC, column packed with reverse phase media (C18). De-salting was done by passing 3 void volume of 0.1M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water. The fractions collected and purity of fractions are monitored by analytical HPFC.
  • the present invention provides a process for preparing Etelcalcetide acetate of Formula (VI), which comprises purifying crude compound of Formula (IV) to form compound of Formula (V), followed by concentrating solution containing compound of Formula (V) by Nano filtration using membrane and contacted with F-Cysteine to obtain Etelcalcetide acetate of Formula (VI); Purifying crude compound of Formula (IV) on preparative HPLC is performed with buffer system comprising 0.5% acetic acid as buffer A and 100% acetonitrile as buffer B to form compound of Formula (V) and subjecting the solution of compound of formula (V) to Nano fdtration using 300 D molecular weight cut-off membrane and concentration up to l/5 th volume (from original volume) and added equal amount of water to the retentate and concentrate of 20 grams/Liter as final concentration.
  • L-cysteine used is in the form of L-cysteine hydrochloride and L-cysteine hydrochloride monohydrate.
  • the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I); tys-OH
  • Linear peptide compound of formula (III) is dissolved in degassed aqueous methanol at a concentration of lgram / 100 ml. After dissolution of H-Cys(Scm)- OH .TFA is added and stirred for 1 hour. Progress of reaction was monitored by analytical reverse phase HPLC & Ellman s test. After completion of reaction the obtained crude Etelcalcetide was filtered through 2.4 micron filter and used as such for next stage purification.
  • Etelcalcetide (crude) is purified on preparative HPLC, column packed with reverse phase media using gradient method, where buffer is 0.5% acetic acid / ammonium acetate and 100% acetonitrile (as buffer B). The fractions are collected and purity of fractions monitored by analytical HPLC. Fractions containing > 95% pure are pooled as main pool; and fractions not meeting the pooling criteria re-processed in a similar manner.
  • the main pool is diluted with equal amount of purified water or organic modifier is removed under vacuum and thereafter loaded on preparative HPLC, column packed with polymeric reverse phase media.
  • De-salting is done by passing 3 void volume of 0.1M ammonium chloride in purified water followed by elution of product from the column by using very dilute HC1 in purified water.
  • fractions are collected, and purity of fractions monitored by analytical HPLC.
  • Example-1 Synthesis of Ac-D-Cys(Trt)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D- Arg(pbf)-D-Ala-D-Arg(pbf)-NH- Resin
  • Rink amide AM Resin 1.21 kg, (substitution 0.66 mill mole/gram) was taken in a 20 L SPPS reactor, 12.1 L of DMF was added and allowed it to swell for 20 minutes and drained.
  • the above resin was de-blocked with one bed volume of 20 % piperidine in DMF (twice) for 5 minutes and 20 minutes and washed with one bed volume of DMF (2 times), IPA (2 times) and DMF (2 times).
  • Diisopropylcarbodiimide (308 mL, 2.5 equivalents) was added and stirred the reaction mixture for 3 minutes. It was added to the resin in Step A and stirred for two hours at room temperature. The progress of the coupling was monitored by Kaiser Test. After completion of the reaction, the resin was drained and washed with one bed volume DMF for 5 minutes and drained.
  • the above resin was deblocked with one bed volume of 20 % piperidine in DMF (twice) for 5 minutes and 20 minutes and washed with one bed volume of DMF (2 times), IPA (2 times) and DMF (2 times).
  • Example-2 Preparation of Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D- Arg-NFh (Linear Peptide). Deblocking of protected peptide was performed with a Cocktail of TFA+TIS+Water+DTT+Phenol (85%+5%+2.5%+2.5+5) for 3 hours at room temperature. The crude peptide was isolated by precipitating with pre-cool MTBE and dried under vacuum to obtain linear peptide.
  • Example-3 Preparation and Purification of Ac-D-Cys(Scm)-D-Ala-D-Arg-D- Arg-D-Arg-D-Ala-D-Arg-NEh .
  • Linear peptide (806.0 grams) obtained from Example-2 was treated with methoxycarbonyl sulfenyl chloride (88.0 mL, 1.1 equivalents) in Trifluoroacetic acid for half an hour, completion of reaction was monitored by HPLC.
  • the crude peptide was isolated by precipitating with pre-cool MTBE and dried under vacuum to obtain linear(scm) peptide (crude) 1.1 kg.
  • Example-3 The solution obtained from Example-3 was subjected to Nano filtration using 300 Daltons molecular weight cut-off membrane and concentration up to l/5 th volume (from original volume). Add equal amount of water to the retentate and concentrate of 20 gram/Liter as final concentration .
  • Example-4 The solution obtained from Example-4 were loaded on preparative HPLC, column packed with reverse phase media (C18). De-salting was done by passing 3 void volume of 0.1 M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water. The fractions were collected and purity of fractions were monitored by analytical HPLC. The fractions containing pure Etelcalcetide hydrochloride (>98.5%) were pooled and filtered through 0.2 micron filter. The resulting peptide solution was freeze-dried to isolate Etelcalcetide as hydrochloride salt. Practical weight: 252 grams;
  • Linear peptide obtained from Example-2 was dissolved in degassed aqueous methanol at a concentration of 1 gram / 100 ml. After dissolution of H-Cys(Scm)- OH .TFA (2 equivalents) was added and stirred for 1 hour. Progress of reaction was monitored by analytical reverse phase HPLC & Elman’s test, after completion of reaction the obtained crude Etelcalcetide was filtered through 2.4 micron filter and used as such for next stage purification.
  • Crude Etelcalcetide solution obtained from Example-6 was purified on preparative HPLC, column packed with polymeric reverse phase media using gradient method, where buffer is 0.5% Acetic acid / Ammonium acetate and 100% acetonitrile (as buffer B). The fractions were collected and purity of fractions were monitored by analytical HPLC. Fractions containing > 95% pure were pooled as main pool; and fractions not meeting the pooling criteria were re processed in a similar manner.
  • Example-8 Salt Exchange and Lyophilization
  • the main pool obtained from Example-7 were diluted with equal amount of purified water or organic modifier was removed under vacuum and thereafter loaded on preparative HPLC, column packed with reverse phase media.
  • De -salting was done by passing 3 void volume of 0.1 M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Organic Chemistry (AREA)
  • Medicinal Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biophysics (AREA)
  • Biochemistry (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Molecular Biology (AREA)
  • Genetics & Genomics (AREA)
  • Pharmacology & Pharmacy (AREA)
  • Engineering & Computer Science (AREA)
  • Animal Behavior & Ethology (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • General Chemical & Material Sciences (AREA)
  • Diabetes (AREA)
  • Endocrinology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Peptides Or Proteins (AREA)
  • Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The present invention relates to an improved process for the preparation of Etelcalcetide hydrochloride of Formula (I) : The present invention also provides a process for preparing Etelcalcetide acetate of Formula (VI), which is an intermediate of Etelcalcetide hydrochloride : Formula (VI)

Description

AN IMPROVED PROCESS FOR THE PREPARATION OF
ETELCALCETIDE HYDROCHLORIDE
FIELD OF THE INVENTION The present invention relates to an improved process for the preparation of Etelcalcetide hydrochloride of Formula (I).
Figure imgf000002_0001
tys-OH
Formula (I)
BACKGROUND OF THE INVENTION Etelcalcetide is a synthetic peptide calcium-sensing receptor agonist. Etelcalcetide is 8 amino acid peptide with the following Chemical name: N-acetyl-D-cysteinyl- S-(L-cysteine disulfide)-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D- argininamide and this can be structurally represented as follows:
Figure imgf000002_0002
This drug was approved as its hydrochloride salt. The Etelcalcetide hydrochloride of Formula (I) is shown below:
Figure imgf000002_0003
tys-OH
Formula (I) Etelcalcetide is approved in the United States under the trade name PARSABIV® for the treatment of Secondary hyperparathyroidism (HPT) in adult patients with chronic kidney disease (CKD) on hemodialysis.
Etelcalcetide is first described in US patent US 8,377,880. The US ’880 patent discloses a process to prepare peptides and conjugates by solid-phase chemistry at 0.25 mmol scale on an ABI automated synthesizer. Sequential coupling of Fmoc- amino acids (4 eq, Anaspec) to Rink-amide resin (Novabiochem) was accomplished using HBTU/DIEA activation. The assembled peptide was cleaved with a TFA cocktail (phenol (5%), triisopropylsilane (2.5%) and water (2.5%); 10 mL per gram of resin) and isolated by precipitation with diethyl ether. After purification using Cl 8 HPLC the final product was isolated in the TFA salt form by lyophilization of appropriate fractions and characterized by HPFC (>95% purity) and EC -MS (confirmed MW).
US Patent application US 2017/0190739 involves conversion of Etelcalcetide TFA salt to Etelcalcetide hydrochloride salt by the addition of 12M aqueous hydrochloric acid. Use of such a high concentrated hydrochloric acid may hydrolyze the peptide resulting in formation of undesired impurities.
US Patent application US 2018/0079777 & Chinese Patent application CN 107434820 uses Iodine, dimethyl sulfoxide & hydrogen peroxide, a conventional method of disulphide bond formation leads to the formation of Etelcalcetide dimers, Cystine and other linear impurities.
However, the processes disclosed in the said documents suffer one or the other problems such as an overall low yield due to formation of high levels of impurities such as Etelcalcetide dimers, Cystine impurities, and other linear impurities. Therefore, there is a need to develop an improved process for the preparation of Etelcalcetide, which is simple, cost-effective, high purity and high yield, avoids/ reduces content of impurities, makes the process robust and particularly one appropriate for commercial scale manufacturing.
OBJECTIVE OF THE INVENTION
The main objective of the present invention is to provide an improved process for the preparation of Etelcalcetide hydrochloride of Formula (I) by using novel compounds of formula (IV) and (V).
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xHCl
A-s tys-OH
Formula (I)
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2
Formula (IV)
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Formula (V) Another objective of the present invention is to provide purification of solution of compound of formula (V) by concentrating the solution using Nano filtration with membrane.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I),
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xHCl
Es tys-OH
Formula (I) which comprises: a) Global de-protecting of compound of Formula (II) to form compound of Formula (III);
Ac-D-Cys(X)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D-Arg(pbf)-D-Ala-D-Arg(pbf)-NH-Resin
Formula (P)
Ac-D-Cys(X)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (III)
Wherein, X is H, side chain protecting groups; b) Reacting compound of Formula (III) with methoxycarbonylsulfenyl chloride (Scm) to form crude compound of Formula (IV);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (IV) c) Purifying crude compound of Formula (IV) to form compound of Formula (V), followed by contacted with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Formula (V)
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
S-S tys-OH
Formula (VI) d) Converting Etelcalcetide acetate of Formula (VI) to Etelcalcetide hydrochloride of Formula (I).
In another aspect, the present invention provides a process for preparing Etelcalcetide acetate of Formula (VI), which comprises purifying crude compound of Formula (IV) to form compound of Formula (V), followed by concentrating solution containing compound of Formula (V) by Nano filtration using membrane and contacted with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI).
In further aspect, the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I);
Figure imgf000006_0001
Formula (I) which comprises; a) Reacting linear peptide of Formula (Ilia)
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (Ilia) with H-Cys(Scm)-OH. TFA to form crude Etelcalcetide.
Figure imgf000006_0002
tys-OH
Etelcalcetide b) Purifying crude Etelcalcetide on preparative HPLC, followed by salt exchange to obtain Etelcalcetide hydrochloride of Formula (I).
BRIEF DESCRIPTION OF ABBREVIATIONS AND DEFININTIONS
Figure imgf000006_0003
Figure imgf000007_0001
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a process for the preparation of Etelcalcetide Hydrochloride.
In one embodiment, the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I);
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xHCl
A-s tys-OH
Formula (I) which comprises: a) Global de-protecting of compound of Formula (II) to form a compound of Formula (III);
Ac-D-Cys(X)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D-Arg(pbf)-D-Ala-D-Arg(pbf)-NH-Resin
Formula (P)
Ac-D-Cys(X)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (III) Wherein, X is H, side chain protecting groups; b) Reacting compound of Formula (III) with methoxycarbonylsulfenyl chloride (Scm) to form crude compound of Formula (IV);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (IV) c) Purifying crude compound of Formula (IV) to form compound of Formula (V), followed by contacted with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Formula (V)
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
S-S tys-OH Formula (VI) d) Converting Etelcalcetide acetate of Formula (VI) to Etelcalcetide hydrochloride of Formula (I). Compound of Formula (II) can be obtained according to the processes known in the art.
The side chain protecting groups (X) used in step a) is selected from the group consisting of acetamidomethyl (Acm), trityl (Trt), benzyl (Bzl), tert-butyl (tBu), tert-butylthio (tButhio), p-methoxybenzyl (pMeoBzl), Phenylacetamidomethyl (Phacm), 4-methyltrityl (Mtt) and 4-methoxytrityl (Mmt). Preferably acetamidomethyl (Acm), trityl (Trt) and Benzyl (Bzl).
The global de-protection is performed in presence of cocktail mixture selected from TFA, TIPS, DTT, TIS, EDT, DMS, thioanisole, phenol, anisole or mixture thereof. Preferably TFA:TIPS:DTT:solvcnt (or) TFA TIPS DTT: water: solvent (or) TFA :TIS: solvent. Wherein, the solvent is comprising water, dimethyl sulfide, methanol, ethanol, 1-propanaol, isopropanol, n-butanol, dichloromethane, dichloroethane, chlorobenzene, diethyl ester, tetrahydrofuran, diisopropyl ether or mixture thereof. Preferably TFA:TIS:Water:DTT:Phenol.
Linear peptide compound of Formula (III) reacts with Methoxycarbonylsulfenyl chloride (Scm) in the presence of trifluoroacetic acid followed by isolating crude peptide compound of formula (IV) by precipitating with pre-cool MTBE, followed by dried under vacuum.
Further, purifying crude compound of Formula (IV) on preparative HPFC is performed with buffer system comprising 0.5% acetic acid as buffer A and 100% acetonitrile as buffer B to form compound of Formula (V) and subjecting the solution of compound of Formula (V) to Nano filtration using 300 D molecular weight cut-off membrane and concentration up to l/5th volume (from original volume) and added equal amount of water to the retentate and concentrate of 20 grams/Fiter as final concentration. The concentrated solution is contacted with F- cysteine to obtain Etelcalcetide acetate of Formula (VI).
F-cysteine is selected from F-cysteine hydrochloride and F-cysteine hydrochloride monohydrate.
Etelcalcetide acetate of Formula (VI) is loaded on preparative HPFC, column packed with reverse phase media (C18). De-salting was done by passing 3 void volume of 0.1M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water. The fractions collected and purity of fractions are monitored by analytical HPFC.
The fractions containing pure Etelcalcetide hydrochloride (>98.5%) are pooled and filtered through 0.2 micron filter. The resulting peptide solution is freeze- dried to isolate Etelcalcetide hydrochloride of Formula (I).
In another embodiment, the present invention provides a process for preparing Etelcalcetide acetate of Formula (VI), which comprises purifying crude compound of Formula (IV) to form compound of Formula (V), followed by concentrating solution containing compound of Formula (V) by Nano filtration using membrane and contacted with F-Cysteine to obtain Etelcalcetide acetate of Formula (VI); Purifying crude compound of Formula (IV) on preparative HPLC is performed with buffer system comprising 0.5% acetic acid as buffer A and 100% acetonitrile as buffer B to form compound of Formula (V) and subjecting the solution of compound of formula (V) to Nano fdtration using 300 D molecular weight cut-off membrane and concentration up to l/5th volume (from original volume) and added equal amount of water to the retentate and concentrate of 20 grams/Liter as final concentration. The concentrated solution is contacted with L-cysteine to obtain Etelcalcetide acetate of Formula (VI). L-cysteine used is in the form of L-cysteine hydrochloride and L-cysteine hydrochloride monohydrate.
In further embodiment, the present invention provides a process for preparing Etelcalcetide hydrochloride of Formula (I);
Figure imgf000010_0001
tys-OH
Formula (I)
Which comprises; a) Reacting linear peptide of Formula (Ilia) Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (Ilia) with H-Cys(Scm)-OH. TFA to form crude Etelcalcetide.
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2
A- S tys-OH
Etelcalcetide b) Purifying crude Etelcalcetide on preparative HPLC, followed by salt exchange to obtain Etelcalcetide hydrochloride of Formula (I). Linear peptide compound of formula (III) is dissolved in degassed aqueous methanol at a concentration of lgram / 100 ml. After dissolution of H-Cys(Scm)- OH .TFA is added and stirred for 1 hour. Progress of reaction was monitored by analytical reverse phase HPLC & Ellman s test. After completion of reaction the obtained crude Etelcalcetide was filtered through 2.4 micron filter and used as such for next stage purification.
Etelcalcetide (crude) is purified on preparative HPLC, column packed with reverse phase media using gradient method, where buffer is 0.5% acetic acid / ammonium acetate and 100% acetonitrile (as buffer B). The fractions are collected and purity of fractions monitored by analytical HPLC. Fractions containing > 95% pure are pooled as main pool; and fractions not meeting the pooling criteria re-processed in a similar manner.
The main pool is diluted with equal amount of purified water or organic modifier is removed under vacuum and thereafter loaded on preparative HPLC, column packed with polymeric reverse phase media.
De-salting is done by passing 3 void volume of 0.1M ammonium chloride in purified water followed by elution of product from the column by using very dilute HC1 in purified water.
The fractions are collected, and purity of fractions monitored by analytical HPLC.
The fractions containing pure Etelcalcetide hydrochloride (>98.5%) are pooled and filtered through 0.2 micron filter. The resulting peptide solution freeze-dried to isolate Etelcalcetide hydrochloride of Formula (I).
Having described the invention with reference to certain aspects and embodiments, which will become apparent to one skilled in the art from consideration of the specification. The invention is further defined by reference to the following examples. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the invention. Examples
Example-1: Synthesis of Ac-D-Cys(Trt)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D- Arg(pbf)-D-Ala-D-Arg(pbf)-NH- Resin
Step A
Rink amide AM Resin 1.21 kg, (substitution 0.66 mill mole/gram) was taken in a 20 L SPPS reactor, 12.1 L of DMF was added and allowed it to swell for 20 minutes and drained.
Step B
The above resin was de-blocked with one bed volume of 20 % piperidine in DMF (twice) for 5 minutes and 20 minutes and washed with one bed volume of DMF (2 times), IPA (2 times) and DMF (2 times).
Step C
Fmoc-D-Arg(pbf)-OH (780.0 grams, 1.5 equivalents.) and HOBT.H2O (184.0 grams, 1.5 equivalents) were dissolved in DMF (6.0 L), and
Diisopropylcarbodiimide (308 mL, 2.5 equivalents) was added and stirred the reaction mixture for 3 minutes. It was added to the resin in Step A and stirred for two hours at room temperature. The progress of the coupling was monitored by Kaiser Test. After completion of the reaction, the resin was drained and washed with one bed volume DMF for 5 minutes and drained.
Encapping: A solution of Diisopropylethylamine (420.0 mL, 3 equivalents) was prepared in dichloromethane (6.0 L), acetic anhydride (228.0 mL, 3 equivalents) and added to the resin. It was stirred for 30 minutes and drained.
Washed the resin with a) one bed volume DMF for 3 minutes (2 times) and drained. b) one bed volume IPA for 3 minutes (2 times) and drained. c) one bed volume DMF for 3 minutes (2 times) and drained. The above resin was deblocked with one bed volume of 20 % piperidine in DMF (twice) for 5 minutes and 20 minutes and washed with one bed volume of DMF (2 times), IPA (2 times) and DMF (2 times).
Step D
Fmoc-D-Ala-OH (500.0 grams, 2 equivalents.) and HOBT.H2O (248.0 grams, 2 equivalents) were dissolved in DMF (6.0 L) and while stirring DIC (372.0 mL, 3 equivalents) was added and stirred the reaction mixture for 3 minutes. It was added to the resin and stirred for two to three hours at room temperature. The progress of coupling was monitored by Kaiser Tests. After completion of the reaction the resin was drained and washed with one bed volume of DMF.
The repeated cycles of operations (Fmoc Deprotections and Amino acid couplings) were performed sequentially for Fmoc-D-Arg(pbf)-OH, Fmoc-D- Arg(pbf)-OH, Fmoc-D-Arg(pbf)-OH, Fmoc-D-Ala-OH and Fmoc-D-Cys(Trt)- OH, to obtain H-D-Cys(Trt)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D-Arg(pbf)-D-Ala- D-Arg(pbf)-NH-Resin
Step E
N-Acetylation:
A solution of acetic anhydride (228.0 mL, 3 equivalents) was prepared in DMF (8.48 L) and added to the resin. It was stirred for 30 minutes and drained.
Prepared a solution of acetic anhydride (228.0 mL, 3 equivalents) in DMF (8.48 L) and added to the resin. It was stirred for 30 minutes and drained.
The progress of Acetylation was monitored by Kaiser Test. After completion of the reaction the resin was drained and washed with one bed volume of DMF (2 times), one bed volume of IPA (2 times) and one bed volume of MTBE (2 times). Finally the peptide resin was isolated and dried to obtained Ac-D-Cys(Trt)-D-Ala- D-Arg(pbf)-D-Arg(pbf)-D-Arg(pbf)-D-Ala-D-Arg(pbf)-NH-Resin;
Peptidyl resin: 3.2 kg.
Example-2: Preparation of Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D- Arg-NFh (Linear Peptide). Deblocking of protected peptide was performed with a Cocktail of TFA+TIS+Water+DTT+Phenol (85%+5%+2.5%+2.5+5) for 3 hours at room temperature. The crude peptide was isolated by precipitating with pre-cool MTBE and dried under vacuum to obtain linear peptide.
Weight: 808.0 grams, Yield: 96.8% , Purity by HPLC: 58.32% .
Example-3: Preparation and Purification of Ac-D-Cys(Scm)-D-Ala-D-Arg-D- Arg-D-Arg-D-Ala-D-Arg-NEh .
Linear peptide (806.0 grams) obtained from Example-2 was treated with methoxycarbonyl sulfenyl chloride (88.0 mL, 1.1 equivalents) in Trifluoroacetic acid for half an hour, completion of reaction was monitored by HPLC.
The crude peptide was isolated by precipitating with pre-cool MTBE and dried under vacuum to obtain linear(scm) peptide (crude) 1.1 kg.
Crude obtained was purified on preparative HPLC, column packed with reverse phase media (Cl 8) using gradient method, where buffer A is 0.5% Acetic acid and 100% acetonitrile as buffer B.
The fractions were collected, and purity of fractions were monitored by analytical HPLC.
Fractions containing > 95% pure were pooled as main pool; and fractions not meeting the pooling criteria were re-processed in a similar manner 766.0 grams of compound present in Main Pool.
Yield: 84.2%, Purity by HPLC: 98.48 %.
Example-4: Preparation of Etelcalcetide acetate
The solution obtained from Example-3 was subjected to Nano filtration using 300 Daltons molecular weight cut-off membrane and concentration up to l/5th volume (from original volume). Add equal amount of water to the retentate and concentrate of 20 gram/Liter as final concentration .
The concentrated solution was treated with cysteine for 30 minutes to obtain Etelcalcetide as acetate salt, Purity by HPLC: 93.67 %.
Example-5: Salt Exchange and Lyophilization
The solution obtained from Example-4 were loaded on preparative HPLC, column packed with reverse phase media (C18). De-salting was done by passing 3 void volume of 0.1 M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water. The fractions were collected and purity of fractions were monitored by analytical HPLC. The fractions containing pure Etelcalcetide hydrochloride (>98.5%) were pooled and filtered through 0.2 micron filter. The resulting peptide solution was freeze-dried to isolate Etelcalcetide as hydrochloride salt. Practical weight: 252 grams;
Yield: 30.07%; Purity by HPLC : 99.70%; Mass: 1047.5 Dalton’s.
Example-6: Preparation of Crude Etelcalcetide
Linear peptide obtained from Example-2 was dissolved in degassed aqueous methanol at a concentration of 1 gram / 100 ml. After dissolution of H-Cys(Scm)- OH .TFA (2 equivalents) was added and stirred for 1 hour. Progress of reaction was monitored by analytical reverse phase HPLC & Elman’s test, after completion of reaction the obtained crude Etelcalcetide was filtered through 2.4 micron filter and used as such for next stage purification.
Example-7: Purification of Crude Etelcalcetide
Crude Etelcalcetide solution obtained from Example-6 was purified on preparative HPLC, column packed with polymeric reverse phase media using gradient method, where buffer is 0.5% Acetic acid / Ammonium acetate and 100% acetonitrile (as buffer B). The fractions were collected and purity of fractions were monitored by analytical HPLC. Fractions containing > 95% pure were pooled as main pool; and fractions not meeting the pooling criteria were re processed in a similar manner.
Example-8: Salt Exchange and Lyophilization The main pool obtained from Example-7 were diluted with equal amount of purified water or organic modifier was removed under vacuum and thereafter loaded on preparative HPLC, column packed with reverse phase media.
De -salting was done by passing 3 void volume of 0.1 M ammonium chloride in purified water fallowed by elution of product from the column by using very dilute HC1 in purified water.
The fractions were collected and purity of fractions were monitored by analytical HPLC.
The fractions containing pure Etelcalcetide hydrochloride (>98.5 %) were pooled and filtered through 0.2 micron filter. The resulting peptide solution was freeze- dried to isolate Etelcalcetide as hydrochloride salt.

Claims

WE CLAIM:
1. A process for preparation of Etelcalcetide hydrochloride of Formula (I);
Figure imgf000017_0001
tys-OH
Formula (I)
Which comprises:
(a) Global de-protecting of compound of Formula (II) to obtain a compound of Formula (III);
Ac-D-Cys(X)-D-Ala-D-Arg(pbf)-D-Arg(pbf)-D-Arg(pbf)-D-Ala-D-Arg(pbf)-NH-Resin
Formula (II)
Ac-D-Cys(X)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (III)
Wherein, X is H, side chain protecting groups;
(b) Reacting compound of Formula (III) with methoxycarbonylsulfenyl chloride (Scm) in the presence trifluoroacetic acid to obtain crude compound of Formula
(IV);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (IV) c) Purifying crude compound of Formula (IV) to obtain compound of Formula
(V), followed by contacted with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Formula (V)
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
S-S tys-OH
Formula (VI) d) Converting Etelcalcetide acetate of Formula (VI) to Etelcalcetide hydrochloride of Formula (I).
2. The process as claimed in claim 1, wherein, the side chain protecting groups (X) used in step (a) is selected from the group comprises Acm, Trt, Bzl, tBu, tButhio, pMeoBzl, Phacm, Mtt or Mmt.
3. The process as claimed in claim 1, wherein the global de-protection using cocktail mixture selected from TFA, TIPS, DTT, TIS, EDT, DMS, thioanisole, phenol, anisole or mixture thereof.
4. The process as claimed in claim 3, wherein the global de-protection using cocktail mixture selected from TFA:TIPS:DTT:solvent (or) TFA:TIPS:DTT: water: solvent (or) TFA :TIS: solvent (or) EDT, DMS, thioanisole, phenol, anisole or mixture thereof.
5. The process as claimed in claim 4, wherein the solvent selected from water, dimethyl sulfide, methanol, ethanol, 1-propanaol, isopropanol, n-butanol, dichloromethane, dichloroethane, chlorobenzene, diethyl ester, tetrahydrofuran, diisopropyl ether or mixture thereof.
6. The process as claimed in claim 1, wherein step (c) is performed on preparative HPFC with buffer system comprises 0.5 % acetic acid as buffer A and 100% acetonitrile as buffer B.
7. The process as claimed in claim 1, wherein F-cysteine used in step (c) is in the form of F-cysteine hydrochloride and F-cysteine hydrochloride monohydrate.
8. A process for preparation of Etelcalcetide acetate of Formula (VI); Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Ls tys-OH
Formula (VI)
Which comprises: a) purifying crude compound of Formula (IV) with 0.5% acetic acid (buffer A) and 100% acetonitrile (buffer B) to obtain compound of Formula (V);
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2 Formula (IV)
Ac-D-Cys(Scm)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2. xCH3COOH
Formula (V) b) concentrating solution containing compound of Formula (V) by Nano fdtration using membrane; c) contacting the compound of Formula (V) with L-Cysteine to obtain Etelcalcetide acetate of Formula (VI).
9. A process for preparation of Etelcalcetide hydrochloride of Formula (I);
Figure imgf000019_0001
tys-OH
Formula (I)
Which comprises: a) Reacting linear peptide of Formula (Ilia)
Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH2
Formula (Ilia) with H-Cys(Scm)-OH. TFA to form crude Etelcalcetide;
Figure imgf000019_0002
tys-OH
Etelcalcetide b) Purifying crude Etelcalcetide with 0.5% acetic acid or ammonium acetate (buffer A) and 100% acetonitrile (buffer B), followed by salt exchange to obtain Etelcalcetide hydrochloride of Formula (I).
PCT/IB2020/057916 2019-08-26 2020-08-25 An improved process for the preparation of etelcalcetide hydrochloride Ceased WO2021038431A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP20857261.0A EP4021920A4 (en) 2019-08-26 2020-08-25 IMPROVED PROCESS FOR THE PREPARATION OF ETELCALKETIDE HYDROCHLORIDE
US17/638,181 US20220298206A1 (en) 2019-08-26 2020-08-25 An improved process for the preparation of Etelcalcetide Hydrochloride

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN201941034285 2019-08-26
IN201941034285 2019-08-26

Publications (1)

Publication Number Publication Date
WO2021038431A1 true WO2021038431A1 (en) 2021-03-04

Family

ID=74683341

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2020/057916 Ceased WO2021038431A1 (en) 2019-08-26 2020-08-25 An improved process for the preparation of etelcalcetide hydrochloride

Country Status (3)

Country Link
US (1) US20220298206A1 (en)
EP (1) EP4021920A4 (en)
WO (1) WO2021038431A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115806591A (en) * 2023-02-09 2023-03-17 杭州信海医药科技有限公司 Purification method of high-purity vilacatide
US20230331778A1 (en) * 2020-08-31 2023-10-19 Usv Private Limited An improved process for fmoc synthesis of etelcalcetide

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120699096B (en) * 2025-07-07 2026-01-23 苏州天马医药集团天吉生物制药有限公司 Preparation method of eptic peptide

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8377880B2 (en) 2009-07-29 2013-02-19 Kai Pharmaceuticals, Inc. Therapeutic agents for reducing parathyroid hormone levels
WO2016154580A1 (en) * 2015-03-26 2016-09-29 Amgen Inc. Solution phase method for preparing etelcalcetide
WO2017114238A1 (en) * 2015-12-31 2017-07-06 深圳翰宇药业股份有限公司 Method for synthesizing etelcalcetide
US20170190739A1 (en) 2014-04-03 2017-07-06 Amgen Inc. Method for preparing amg 416
CN107434820A (en) 2017-08-07 2017-12-05 南京工业大学 Synthetic method of vilacatide
US20190100554A1 (en) * 2017-10-03 2019-04-04 Chunghwa Chemical Synthesis & Biotech Co. Ltd. Method for synthesizing etelcalcetide or salts thereof

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201208293D0 (en) * 2012-05-11 2012-06-20 Circassia Ltd Hydrochlorice salt of peptide
CN105504012A (en) * 2014-09-30 2016-04-20 深圳翰宇药业股份有限公司 Preparation method of polypeptide

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8377880B2 (en) 2009-07-29 2013-02-19 Kai Pharmaceuticals, Inc. Therapeutic agents for reducing parathyroid hormone levels
US20170190739A1 (en) 2014-04-03 2017-07-06 Amgen Inc. Method for preparing amg 416
WO2016154580A1 (en) * 2015-03-26 2016-09-29 Amgen Inc. Solution phase method for preparing etelcalcetide
US20180079777A1 (en) 2015-03-26 2018-03-22 Amgen Inc. Solution phase method for preparing etelcalcetide
WO2017114238A1 (en) * 2015-12-31 2017-07-06 深圳翰宇药业股份有限公司 Method for synthesizing etelcalcetide
CN107434820A (en) 2017-08-07 2017-12-05 南京工业大学 Synthetic method of vilacatide
US20190100554A1 (en) * 2017-10-03 2019-04-04 Chunghwa Chemical Synthesis & Biotech Co. Ltd. Method for synthesizing etelcalcetide or salts thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4021920A4

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230331778A1 (en) * 2020-08-31 2023-10-19 Usv Private Limited An improved process for fmoc synthesis of etelcalcetide
CN115806591A (en) * 2023-02-09 2023-03-17 杭州信海医药科技有限公司 Purification method of high-purity vilacatide

Also Published As

Publication number Publication date
EP4021920A1 (en) 2022-07-06
US20220298206A1 (en) 2022-09-22
EP4021920A4 (en) 2023-08-16

Similar Documents

Publication Publication Date Title
US10442838B2 (en) Linaclotide synthesis method
CN110054662B (en) Solid-phase synthesis method of Etelcalcetide
WO2021038431A1 (en) An improved process for the preparation of etelcalcetide hydrochloride
JP2010531828A (en) Method for producing plumlintide
US12162957B2 (en) Process for the preparation of plecanatide
JP5328345B2 (en) Method for producing peptide thioester compound
CN113801197A (en) Preparation method of procatide
CN108218957B (en) Method for preparing AMG416 by combining solid phase and liquid phase
KR101694190B1 (en) Process for the Preparation of Ziconotide
CN110204611B (en) Solid phase fragment method for synthesizing bivalirudin
US20230331778A1 (en) An improved process for fmoc synthesis of etelcalcetide
KR101658942B1 (en) Process for the Preparation of Desmopressin
CN112574285A (en) Solid-liquid phase synthesis method of polypeptide drug containing pair of disulfide bonds
WO2021036057A1 (en) Method for preparing nesiritide by means of solid-liquid combination synthesis
CN114945580B (en) Method for synthesizing south Ji Botai
WO2019215753A2 (en) Process for preparation of pure plecanatide
CN111378009A (en) Preparation method of octreotide
WO2013046233A2 (en) Process for the preparation of octreotide acetate
US20220235096A1 (en) An improved process for the preparation of Plecanatide
KR101454892B1 (en) Process for the Preparation of Exenatide
KR102146006B1 (en) Process for the Preparation of Acetyl hexapeptide-3
CN113321723A (en) Preparation method of thymalfasin
CN114805480A (en) Preparation method of octreotide
WO2021026800A1 (en) Method for synthesizing degarelix acetate
CN111499719A (en) Method for synthesizing pramlintide

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20857261

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020857261

Country of ref document: EP

Effective date: 20220328