WO2022034545A1

WO2022034545A1 - Etelcalcetide formulations for parenteral use

Info

Publication number: WO2022034545A1
Application number: PCT/IB2021/057467
Authority: WO
Inventors: Gogu PRAVEEN KUMAR; Donthidi AMARENDER REDDY; Vishnubhotla Nagaprasad; Sivakumaran Meenakshisunderam
Original assignee: Aurobindo Pharma Limited
Priority date: 2020-08-14
Filing date: 2021-08-13
Publication date: 2022-02-17
Also published as: ZA202105829B

Abstract

The present invention relates to a stable injectable formulation comprising i) Etelcalcetide or pharmaceutically acceptable salts or solvates thereof; ii) a buffering agent preferably selected from group consisting of L tartaric acid, Benzene sulfonic acid, Lactic acid or Lactate sodium, Sodium acetate, Sodium citrate, Glycine, Glycine hydrochloride, Maleic acid, Benzoic acid or Sodium benzoate, Monobasic/Dibasic sodium phosphate, Sodium tartrate, Methane sulphonic acid, Histidine and Magnesium succinate or their salts, or a combination thereof; (iii) Sodium chloride; and (iv) pH-adjusting agents. The present invention further relates to process for preparation of such stable formulation of Etelcalcetide, with reduced impurities and enhanced stability. The present invention also relates to use of such formulations comprising Etelcalcetide.

Description

ETELCALCETIDE FORMULATIONS FOR PARENTERAL USE

FIELD OF THE INVENTION

The present invention relates to a stable injectable formulation comprising a biologically active peptide Etelcalcetide, an isotonic agent, a buffering agent, and pH-adjusting agent. The present invention also relates to processes for preparation of such stable formulation of Etelcalcetide, with reduced impurities and enhanced stability. Further the present invention is related to use of such formulations in the treatment of diseases and conditions for which such formulations are indicated.

BACKGROUND OF THE INVENTION

Etelcalcetide is a calcimimetic and calcium-sensing receptor (CaSR) agonist composed of a synthetic peptide comprised of seven D-amino acids that can be used to treat secondary hyperparathyroidism (sHPT) in hemodialysis patients with chronic kidney disease (CKD). Elevated PTH is often observed in patients with CKD and is associated with dysregulated calcium-phosphate homeostasis. Upon intravenous administration, Etelcalcetide mimics calcium and allosterically modulates the CaSR expressed by the parathyroid gland. Etelcalcetide binds to the CaSR and enhances activation of the receptor by extracellular calcium. Activation of the CaSR on parathyroid chief cells decreases PTH secretion, thereby reduces PTH levels. Etelcalcetide Hydrochloride structurally represented as:

Therapeutic peptides are widely used in medical practice. Pharmaceutical formulations of such therapeutic peptides are required to have a good stability in order to be suitable for common use. Further, the said therapeutic peptides are often provided in lyophilized form for later reconstitution, since the lyophilized forms have the advantage of providing stability for long periods of time. However these lyophilized formulations are less convenient to use as they requires the addition of one or more diluents and there is the potential risk for errors due to the use of an improper type or amount of diluent, as well as risk of contamination. In addition, the lyophilization process is time consuming and costly. Furthermore, peptide formulations are inherently unstable due to sensitivity towards physical and chemical degradation. The said physical degradation of the therapeutic peptides involves conformational changes relative to the native structure of the peptide, which may lead to oligomerization, aggregation, precipitation or adsorption to surfaces. The said chemical degradation of peptides, in general, involves change of covalent bonds, such as oxidation, hydrolysis, racemization or crosslinking and deamindation. In particular the peptides that contain a disulfide bond, typically have only moderate or poor stability in aqueous solution. Peptides are prone to amide bond hydrolysis at both high and low pH. Disulfide bonds can be unstable even under quite mild conditions (close to neutral pH). In addition, disulfide containing peptides that are not cyclic are particularly prone to dimer formation. These consequently lead to loss in biological activity of molecule. Etelcalcetide main chain has 7 amino acids, all in the D-configuration and the side-chain cysteine residue is in the L-configuration. The said 7 D-amino acids are linked to L- cysteine by a disulfide bond. The amino terminal is acetylated and the carboxyl-terminal is amidated. Thus, there is a need for a stable aqueous liquid formulation comprising Etelcalcetide. It would be desirable for the said liquid formulation to remain stable over a relevant period of time under suitable storage conditions and to be suitable for administration by intravenous or other parenteral routes.

Several attempts have been made in the prior art to provide optimal and stable injection formulations of Etelcalcetide. U.S. Patent No. 9,820,938 discloses a formulation comprising 2 mg/mLto 20 mg/mL of Etelcalcetide in aqueous solution, a succinate buffer that maintains the formulation at a pH of about 3.0 to 3.5, and a concentration of sodium chloride wherein the formulation is approximately isotonic. It further discloses that the two major degradants of Etelcalcetide injection are the result of C-terminal deamidation and homodimer formation and the time course of degradation by these pathways is a function of the pH of the solution. Furthermore it discloses that, degradation due to C-terminal deamidation by hydrolysis is predominated at low pH and the degradation by homodimer formation is predominated at higher pH. Thus, formation of the two major degradants have the opposite relationship between pH and extent of degradation. The said patent also discloses that deamidation and homodimer formation were decreased as the pH range narrowed around 3.3 using succinate buffer (e.g., sodium succinate), when compared to other exemplary pharmaceutically acceptable buffers including acetate, citrate and lactate. Considering the stability of Etelcalcetide, there is a need for development of pharmaceutical formulations of Etelcalcetide with desired stability at different storage conditions. The formation of degradation products by deamidation and homodimer formation in the Etelcalcetide formulation is detrimental to activity. Moreover, if the amount of degradation product exceeds FDA guidelines, additional safety and toxicology testing must be undertaken. Currently Etelcalcetide is marketed under brand name PARSABIV® which is given by intravenous injection. It is indicated for Secondary hyperparathyroidism (HPT) in adult patients with chronic kidney disease (CKD) on hemodialysis, developed by Amgen. PARSABIV® single-dose vial is formulated with 0.85% (w/v) sodium chloride, 10 mM (or 1.2 mg/mL) succinic acid, and adjusted to pH 3.3 with sodium hydroxide and/or hydrochloric acid. The aforementioned prior art formulations and the currently marketed Etelcalcetide injection formulations with 10 mM (or 1.2 mg/mL) succinic acid buffer exhibits improved stability of Etelcalcetide, but still has impurities due to deamidation and homodimer formation. Further PARSABIV® require storage at refrigerated temperatures and should not be exposed to temperatures above 25 °C and should not be exposed to direct sunlight if removed from the original carton. Given the delicate stability of Etelcalcetide, there remains a need to develop alternative therapeutically effective formulations of Etelcalcetide that are simple, easy to manufacture, and stable. Thus the goal of the present invention is to formulate a stable Etelcalcetide formulation with good stability. It is known in the art that buffers are added to parenteral formulations to optimize solubility and stability by adjusting/maintaining the pH; and it is also known that the buffer strength should be kept as low as possible to avoid pain upon injection. Therefore, the inventors of the present invention have developed pharmaceutical formulations of Etelcalcetide using alternative buffers that have a buffer strength i.e. equivalent to the succinate buffer capacity (used in PARSABIV® injection) and simultaneously maintains the solubility and improves stability of Etelcalcetide. The said formulations of the present invention are stable, easy to manufacture and are commercially viable. The alternative buffers and the process of preparation used in the present invention improves the stability of formulation and alleviates the limitations in the art by providing stable preparations with less quantities of buffer.

SUMMARY OF THE INVENTION

The present invention relates to stable injectable formulations comprising therapeutically effective amount of Etelcalcetide, an isotonic agent, pH-adjusting agents and at least one buffer selected from Tartaric acid, Benzene sulfonic acid, Lactic acid or Lactate sodium, Benzoic acid or Sodium benzoate, Sodium acetate, Sodium citrate, Glycine, Glycine hydrochloride, Maleic acid, Monobasic/Dibasic sodium phosphate, Sodium tartrate, Methane sulphonic acid, Histidine and Magnesium succinate and mixtures thereof;, wherein the said buffers are used in lesser quantities when compared to the buffer quantity used in PARSABIV® injection.

Surprisingly, these formulations (i.e. with lesser quantities of alternate buffers) that are made by a multi-step process using tightly controlled in-process controls provided good stability and the pH of the said formulations was found to be stable along with the impurity profile. In particular, the formulations of the present invention showed less impurities that are formed by deamidation, when compared to impurities present in the currently marketed PARSABIV® injection when stored for a period of at least 6 months. Moreover the present inventors have now surprisingly found that, well-known routine pharmaceutically acceptable buffers in the art and few conventional methods are capable of improving stability of Etelcalcetide formulations, without using of specialized excipients and process. Further, these unique formulations and process were discovered after recognizing the problems of the prior art, and not through routine experimentation and the said combinations of specific buffer and the specific quantities were only be determined empirically.

Aspects of the present invention relates to a stable pharmaceutical formulation comprising: (i) Etelcalcetide; (ii) Sodium chloride; (iii) a buffer selected from the group consisting of Tartaric acid, Benzene sulfonic acid, Lactic acid or Lactate sodium, Benzoic acid or Sodium benzoate, Sodium acetate, Sodium citrate, Glycine, Glycine hydrochloride, Maleic acid, Monobasic/Dibasic sodium phosphate, Sodium tartrate, Methane sulphonic acid, Histidine and Magnesium succinate and mixtures thereof; (iv) a pH adjusting agent and (v) water for injection.

Aspects of the present invention relates to stable pharmaceutical formulations comprising: (i) Etelcalcetide; (ii) a buffer selected from the group consisting of Glycine, Benzoic acid, & L tartaric acid; (iii) Sodium chloride; and (iv) pH- adjusting agents.

Aspects of the present invention relates to a multi-step process with tight in-process controls for preparing the said Etelcalcetide formulations that exhibit reduced impurities, wherein the process comprises the following steps: a) addition of sodium chloride, buffers and Etelcalcetide to water; b) pH adjustment; c) making up to 100% of batch size; d) the said solution was then filled into vials and vial headspace was blanketed with nitrogen to achieve headspace oxygen content less than 10%. Aspects of the present invention relates to stable pharmaceutical formulations comprising: (i) Etelcalcetide; (ii) a buffer selected from the group consisting of Glycine, Benzoic acid, & L tartaric acid; (iii) Sodium chloride; (iv) pH-adjusting agents; (v) less than 10% degradation product when stored at 2-8°C for up to 2 years. In an aspect of the invention, the said stable formulation comprises less impurities that are formed by deamidation, when compared to currently marketed PARSABIV® injection after storing for a period of at least 6 months.

Aspects of the present invention relate to a pharmaceutical formulation comprising Etelcalcetide, Sodium chloride, buffering agents that stabilizes or maintains the pH of the formulation, optionally a preservative / antioxidant and water, wherein the pharmaceutical formulation is having an acidic pH and exhibits less than about 10% degradation after storage at different temperature s/conditions and time periods. Aspects of the present invention relate to an Etelcalcetide formulation in a unit dosage form, wherein the unit dosage form further comprises impurities (less than 10%) and these impurities consists from about 0% to about 2% impurities that are formed by deamidation.

Aspects of the present invention relates to a method of using the said stable Etelcalcetide formulations for Secondary hyperparathyroidism (HPT) in adult patients with chronic kidney disease (CKD) on hemodialysis. The present invention further relates to methods of treatment using the said pharmaceutical formulations of the invention by administering an amount effective to combat the disease, condition, or disorder for which administration of Etelcalcetide in the formulation is indicated.

In an aspect of the present invention, the buffering agents stabilizes the pH of the Etelcalcetide formulation, wherein the preferred buffering agents are selected from Tartaric acid, Benzene Sulfonic acid, Lactic acid or Lactate sodium, Benzoic acid or Sodium Benzoate, Sodium Acetate, Sodium Citrate, Glycine, Glycine Hydrochloride, Maleic acid, Monobasic /Dibasic sodium phosphate, Sodium tartrate, Methane Sulphonic acid, Histidine and Magnesium succinate buffer and mixtures thereof.

The formulations of the present invention remain stable for significant time and at different temperature s/conditions, during storage/transport and in-use period, after exposure to multiple freeze-thaw cycles, or after being subjected to different production process (including stirring, filtration and pH adjustment etc) which can cause aggregation or damage to their secondary structure.

DETAILED DESCRIPTION OF THE INVENTION

In embodiments, the pharmaceutical formulation provided herein comprises (i) Etelcalcetide; (ii) Sodium chloride; (iii) buffer selected from the group consisting of Tartaric acid, Benzene sulfonic acid, Lactic acid or Lactate sodium, Benzoic acid or Sodium benzoate, Sodium acetate, Sodium citrate, Glycine, Glycine hydrochloride, Maleic acid, Monobasic /Dibasic sodium phosphate, Sodium tartrate, Methane sulphonic acid, Histidine and Magnesium succinate buffer and mixtures thereof; (iv) pH adjusting agent and (v) Water For Injection. In embodiments, the pharmaceutical formulation provided herein comprises a buffer that is present at a concentration of 0.1 mg/mL to 400 mg/mL. In one embodiment, the buffer is present at a concentration of 0.3 mg/mL to 10 mg/mL. In another embodiment, the buffer is present at a concentration of 0.4 mg/mL to 3 mg/mL. Preferably the buffer is present at a concentration of about 0.4 mg/mL to about 1.2 mg/mL.

In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) L-Tartaric acid as buffering agent, (iii) Sodium chloride, (iv) pH adjusting agent and (v) Water for Injection, wherein the formulation has a pH of 2.8 to 4.0. In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) L- Tartaric acid as buffering agent, (iii) Sodium chloride, (iv) pH adjusting agent and (v) Water for Injection, wherein the pH is adjusted to about 3.0 to about 3.6. In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) Glycine as buffering agent, (iii) Sodium chloride, (iv) pH adjusting agent and (v) Water for Injection, wherein the formulation has a pH of 2.8 to 4.0.

In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) Glycine as buffering agent, (iii) Sodium chloride,

(iv) pH adjusting agent and (v) Water for Injection, wherein the pH is adjusted to about 3.0 to about 3.6.

In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) Benzoic acid as buffering agent, (iii) Sodium chloride, (iv) pH adjusting agent and (v) Water for Injection, wherein the formulation has a pH of 2.8 to 4.0. In one of the embodiments, the stable pharmaceutical formulation provided herein comprises (i) Etelcalcetide, (ii) Benzoic acid as buffering agent, (iii) Sodium chloride, (iv) pH adjusting agent and

(v) Water for Injection, wherein the pH is adjusted to about 3.0 to about 3.6

In embodiments, the pharmaceutical formulation provided herein comprises Etelcalcetide at a concentration of 0.1 mg/mL to 20 mg/mL. In one embodiment, the Etelcalcetide is present at a concentration of 1 mg/mL to 15 mg/mL. In another embodiment, Etelcalcetide is present at a concentration of 2.5 mg/mL to 10 mg/mL. In another embodiment, Etelcalcetide is present at a concentration of about 1 mg/mL, about 5 mg/mL or about 10 mg/mL. In another embodiment, Etelcalcetide is present as Etelcalcetide hydrochloride.

In embodiments, Sodium chloride is preferably used as an isotonic agent in the pharmaceutical formulations of the present invention, where the Sodium chloride is present in a concentration of 1-30 mg/ml. However, it can be replaced or used in combination with dextrose, potassium chloride, mannitol, sorbitol, trehalose, lactitol, xylitol, glycerol, sucrose, glycine, lactose, glucose, glycerin, maltose, lysine, isoleucine, aspartic acid, L- glycine, L-histidine, arginine, myo-inositol, polyethylene glycol, or combinations thereof. In another embodiment, the isotonic agent (or mixture of isotonic agents) is present at a concentration sufficient for the formulation to be approximately isotonic with bodily fluids (e.g., human blood).

In embodiments, the formulation of the present invention has an acidic pH of between about 2.8 to about 4.3. In another embodiment, the formulation has a pH of 3.0 to 3.9. In one embodiment, the formulation has a pH of 2.9 to 3.5. In another embodiment, the formulation has a pH of 2.8 to 3.6. Further, the pH with respect to the said formulation was found to be relatively stable along with the impurity profile after exposure to 2-8°C and 25°C/60% relative humidity for about 6 months. Suitable pH-adjusting agents that can be used in the formulation of the present invention is selected from but not limited to a group comprising hydrochloric acid, citric acid, N-methyl glucamine, sodium hydroxide, acetic acid, potassium hydroxide, phosphoric acid, sodium or potassium hydrogen phosphate, lactic acid, and mixtures thereof. The pH may also be adjusted by suitable alkaline solutions including alkali and alkali earth hydroxides, alkali carbonates, alkali acetates, alkali citrates and dialkali hydrogen phosphates, e.g., sodium hydroxide, sodium acetate, sodium carbonate, sodium citrate, disodium or dipotassium hydrogen phosphate, or ammonia. The pH of the solution is adjusted to about 3.0 to about 3.6. Preferably, the pH is adjusted to about 3.0 to about 3.4. More preferably the pH is adjusted to about one of the following values, i.e. 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 or 3.6. The term "about" as used herein in relation to pH means ± 0.5 pH units from the specified value.

In one of the embodiments, measure of the chemical stability of Etelcalcetide is the amount of Etelcalcetide present in the Etelcalcetide formulations relative to the amount of structurally similar compounds including degradants like Etelcalcetide homodimer impurity, Impurity formed by C-terminal deamidation [Arg 7(Acid) Etelcalcetide impurity], Deacetyl Etelcalcetide impurity, Des Cys Impurity and other unspecified impurities. The amount of Etelcalcetide relative to the amount of these structurally similar compounds can be measured by high performance liquid chromatography (HPLC). The purity of Etelcalcetide and amounts of structurally similar compounds can be determined from peak areas obtained from HPLC to provide a measure of Etelcalcetide chemical stability. In another embodiments, stability can also be measured in many ways, including measuring osmolarity or by visually inspecting the formulations in daylight with a dark background for any signs of turbidity, changes in color or clarity, or any other visible precipitates. In embodiments, the said formulation has less than 10% degradation when stored at 2- 8°C. for up to 4 years. In another embodiment, the formulation has less than 10% degradation when stored at room temperature for up to 1 year. In another embodiment, the present invention relates to a stable Etelcalcetide formulation, wherein the said formulation consists of C-terminal deamidation degradation product in an amount that is less than about 1% w/w after exposure to room temperature / 2-8°C for about 6 months. Preferably the formulations of the present invention exhibits less than about 0.5% of C-terminal deamidation degradation product. In another embodiment, the present invention relates to a stable Etelcalcetide formulation, wherein the said formulation consists of Deacetyl Etelcalcetide impurity and Des Cys impurity in an amount that is less than about 1% w/w after exposure to room temperature / 2-8°C for about 6 months. In another embodiment, the present invention relates to a stable Etelcalcetide formulation, wherein the said formulation consists of less impurities than the currently marketed PARSABIV® injection, after exposure to room temperature / 2-8° C for about 6 months, wherein the said impurities include C-terminal deamidation Impurity, Deacetyl Etelcalcetide impurity and Des Cys Impurity. In another embodiment, the present invention relates to a stable Etelcalcetide formulation, wherein the said formulation consists of homodimer impurity in an amount that is comparable to the amount present in the currently marketed PARSABIV® injection, after exposure to room temperature / 2-8° C for about 6 months.

In embodiments, the pharmaceutical formulation provided herein may optionally comprise a preservative, wherein the preservative is selected from the group consisting of phenol, m-cresol, thiomerosal, methyl paraben, propyl paraben, butyl paraben, chlorobutanol, 2-phenylethanol, benzyl alcohol and phenoxyethanol. In a preferred embodiment, the preservative is phenol. In embodiments, the pharmaceutical formulation provided herein may optionally comprise an antioxidant, wherein the antioxidant is selected from the group consisting of cysteine, citric acid, thioglycolic acid, thioglycerol, acetylcysteine, and a combination thereof.

In embodiments, the pharmaceutical formulation provided herein may further optionally comprises a stabilizers and other excipients including a surfactant, and a chelating agent. Suitable examples of stabilizers include polyethylene glycol or its derivatives, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose, sodium chloride, L- glycine, L-histidine, imidazole, arginine, lysine, isoleucine, aspartic acid, tryptophan, threonine, or mixtures thereof. Suitable examples of surfactants include polysorbate, poloxamers, ethylene/polypropylene block polymers, lecithins, alcohols, sodium lauryl sulfate, bile acids and salts thereof, polymeric surfactants, long-chain fatty acids, phospholipids, ethoxylated castor oil, polyglycolyzed glycerides, acetylated monoglycerides, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, monoglycerides, diglycerides, glycerol, glycerophospholipids, glyceroglycolipids, sphingophospholipids, sphingoglycolipids, docusate sodium, docusate calcium, docusate potassium, and mixtures thereof. Suitable examples of chelating agents include ethylenediaminetetraacetic acid or its salts, and mixtures thereof.

In embodiments, the pharmaceutical formulation provided herein can be prepared by multi step process which is tightly controlled by in-process controls. In one embodiment, the process comprises the following steps: a. prepare a solution by dissolving buffer in aqueous medium; b. add and dissolve Sodium chloride to the solution prepared in step a); c. add and dissolve Etelcalcetide to the solution prepared in step b); d. check and adjust the pH of the solution prepared in step d) and make it up

e. filter the solution prepared in step e) to fill the filtrated solution into vials and vial headspace was blanketed with nitrogen to achieve headspace oxygen content less than 8%.

In embodiments, the pharmaceutical formulation provided herein can be prepared by multi step process which is tightly controlled by in-process controls. In one embodiment, the process comprises the following steps: a. prepare a solution by dissolving Sodium chloride in aqueous medium; b. add and dissolve buffer to the solution prepared in step and adjust the pH a); c. add and dissolve Etelcalcetide to the solution prepared in step b); d. check and adjust the pH of the solution prepared in step d) and it make it up to 100% of the batch size with aqueous medium; and e. filter the solution prepared in step e) to fill the filtrated solution into vials and vial headspace was blanketed with nitrogen to achieve headspace oxygen content less than 8%.

In embodiments, the pharmaceutical formulation provided herein is prepared by a multi-step process that is tightly controlled by in-process controls, the suitable process controls that can be employed in the multistep processes of the present invention are selected from the following parameters but not limited to a) stirring at speed of 100 to 1400 rpm, b) stirring until homogeneous mixture is formed, c) filtration with 0.2pm membrane at a pressure of 0.05 to 0.18mpa and combinations thereof. In one embodiment, the stabilized formulation process may optionally comprise steps including but not limited to a) heating, b) drying, c) protection from light i.e. formulation under sodium vapor lamp d) Nitrogen purging and pH adjustment.

In one embodiment, the stabilized formulation of the present invention can be sterilized. Non-limiting examples of sterilization techniques include filtration through a bacterial-retaining filter, terminal sterilization, and incorporation of sterilizing agents, irradiation, and heating. Within the scope of the description of the invention, Etelcalcetide and any of its addition salts are referred to as "Etelcalcetide". The effective therapeutic amount of Etelcalcetide is advantageously about 2.5 mg three times per week to 15 mg three times per week. When the active principle is Etelcalcetide pharmaceutically acceptable salt, the salt content in the formulation is such that the latter comprises from 5 mg/ml of Etelcalcetide base. In embodiments, the expression "stable pharmaceutical formulation" or "stable Etelcalcetide formulation" is intended to mean the formulation of Etelcalcetide, which is stable during different temperatures for a long period of time, shelf stable formulation, and stable in the vial. As used herein, the term "Stabilized formulation” further refers to a stable solution for therapeutic use, containing Etelcalcetide.

The section headings used herein are not to be construed as limiting the subject matter described. Unless otherwise defined herein, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. Generally, nomenclatures used in connection with, and techniques of, molecular biology and protein chemistry described herein are those well-known and commonly used in the art. The methods and techniques of the present application are generally performed according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout the present specification unless otherwise indicated. It should be understood that this disclosure is not limited to the particular methodology, protocols, and reagents, etc., described herein and as such may vary. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the disclosed, which is defined solely by the claims.

The following examples are intended to serve as illustrations of the present invention and not intended to be limiting in any manner. EXAMPLES

Example 1:

The stability of Etelcalcetide for Injection of present invention was evaluated at different storage conditions by various parameters such as assay and related substances including dimer content and deamidation impurities such as Arg 7 (Acid) Etelcalcetide, Des Cys Impurity and De-acetyl-Etelcaletide Impurity. The below tables 1, 2 and 3 shows the comparative stability data of marketed product (P ARSAB IV® Injection) and Example 1 of the present invention at initial and upon different storage periods at 2-8°C and 25°C/60% relative humidity.

Table 1

Stability Parameters at 2-8°C (initial condition):

Table 2

Stability Parameters at 2-8°C (storage condition):

Table 3 Stability Parameters at 25°C/60% Relative Humidity (storage condition):

Based on the above stability studies, Etelcalcetide formulation with L-Tartaric acid as a buffering agent at a concentration of 1 mg/mL is found to be stable and showed less impurities that are formed by deamidation when compared to impurities present in marketed i.e. PARSABIV® injection when stored for a period of at least 6 months at 2-8°C. In view of the above comparative stability data, it can be concluded that L-Tartaric acid as a buffering agent used in the present invention has shown improved stability of Etelcalcetide formulation.

Example 2:

Example 3:

Example 4:

Example 5:

Example 6:

Example 7:

Example 8:

The stability studies of Etelcalcetide for Injection of the present invention was evaluated at different storage conditions by various parameters such as related substances including dimer content and deamidation impurity i.e. Des Cys Impurity. The below tables 4 and 5 shows the comparative stability data of marketed product (PARSABIV® Injection) and Examples 7 and 8 of the present invention upon different storage periods at 25°C/60% relative humidity and 2°C-8°C.

Table 4 Stability Parameters at 25°C/60% Relative Humidity:

Table 5

Stability Parameters at 2-8°C:

Based on the above stability study, Etelcalcetide formulation is found to be stable and showed less impurities that are formed by deamidation when compared to impurities present in marketed i.e. PARSABIV® injection when stored for a period of at least 3 months at 25°C/60% relative humidity and 2°C-8°C. In view of the above comparative stability data, it can be concluded that buffers such as Lactic acid or Lactate sodium and Sodium acetate used in present invention has shown improved stability of Etelcalcetide formulation. Example 9:

Example 10:

Example 11:

Example 12:

Example 13:

Example 14:

Example 15:

A number of other embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the invention.

Claims

22 WE CLAIM:

1. A stable pharmaceutical formulation comprising: (i) Etelcalcetide; (ii) Sodium chloride; (iii) a buffer selected from the group consisting of Tartaric acid, Benzene sulfonic acid, Lactic acid or Lactate sodium, Benzoic acid or Sodium benzoate, Sodium acetate, Sodium citrate, Glycine, Glycine hydrochloride, Maleic acid, Monobasic/Dibasic sodium phosphate, Sodium tartrate, Methane sulphonic acid, Histidine and Magnesium succinate and mixtures thereof; (iv) a pH adjusting agent and (v) water for injection.

2. The stable pharmaceutical formulation according to claim 1, wherein the Etelcalcetide has a concentration of 2.5 mg/mL to 10 mg/mL.

3. The stable pharmaceutical formulation according to claim 1, wherein the buffer has a concentration of 0.4 mg/mL to 3 mg/mL.

4. The stable pharmaceutical formulation according to claim 1, wherein the pH- adjusting agents are selected from the group consisting of hydrochloric acid, citric acid, N-methyl glucamine, sodium hydroxide, acetic acid, potassium hydroxide, phosphoric acid, sodium or potassium hydrogen phosphate, lactic acid, and mixtures thereof.

5. The stable pharmaceutical formulation according to claim 1, wherein the formulation has a pH of between about 2.8 to about 4.3.

6. The stable pharmaceutical formulation according to claim 1, wherein the formulation consists of Arg 7 (Acid) Etelcalcetide impurity, Deacetyl Etelcalcetide impurity and Des Cys impurity in an amount that is less than about 1% w/w after exposure to 2-8 °C for about 6 months.

7. The formulation according to claim 6, wherein the formulation consists of less impurities when compared to marketed product (PARSABIV® Injection) after exposure to 2-8°C for about 6 months.

8. A stable pharmaceutical formulation comprising (i) Etelcalcetide; (ii) a buffer selected from the group consisting of Glycine, Benzoic acid, & L tartaric acid; (iii) Sodium chloride; (iv) pH-adjusting agents; (v) less than 10% degradation product when stored at 2-8 °C for up to 2 years.

9. A stable pharmaceutical formulation comprising (i) Etelcalcetide at a concentration of 0.1 mg/mL to 20 mg/mL, (ii) L-Tartaric acid as a buffering agent at a concentration of 0.4 mg/mL to 3 mg/mL, (iii) Sodium chloride at a concentration of 1 mg/mL to 10 mg/mL, (iv) pH adjusting agents and (v) water for injection, wherein the formulation has a pH of 2.8 to 4.0.

10. A process forthe preparation of stable Etelcalcetide pharmaceutical formulation comprises the following steps a. prepare a solution by dissolving buffer in aqueous medium; b. add and dissolve sodium chloride to the solution prepared in step a); c. add and dissolve Etelcalcetide to the solution prepared in step b); d. check and adjust the pH of the solution prepared in step d) and make it up 10 to 100% of the batch size with aqueous medium; and e. filter the solution prepared in step e) to fill the filtrated solution into vials and vial headspace was blanketed with nitrogen to achieve headspace oxygen content less than 8%.