Stable parenteral dosage form of setrorelix acetate

Abstract

The present invention relates to a stable parenteral dosage form using a sterile, stable, ready-to-inject aqueous solution of cetrorelix acetate. The present invention also relates to an injection device pre-filled with a sterile, stable, ready-to-inject aqueous solution of cetrorelix acetate. The present invention relates to a method for inhibiting a premature luteinizing hormone surge in women undergoing controlled ovarian stimulation, the method comprising a stable parenteral dosage form having a sterile, stable, ready-to-inject aqueous solution of cetrorelix acetate.

Description

Technical Field

[0001] The present invention relates to a stable parenteral dosage form having a sterile and stable aqueous solution of cetrorelix acetate that can be immediately injected. The present invention also relates to an injection device pre-filled with a sterile and stable aqueous solution of cetrorelix acetate that can be immediately injected. The present invention relates to a method for inhibiting premature luteinizing hormone surge in women undergoing controlled ovarian stimulation, the method comprising a stable parenteral dosage form having a sterile and stable aqueous solution of cetrorelix acetate that can be immediately injected.

Background Art

[0002] Cetrorelix is a gonadotropin-releasing hormone antagonist (GnRH antagonist) acetyl-D-3-(2'-naphthyl)-alanine-D-4-chlorophenylalanine-D-3-(3'-pyridyl)-alanine-L-serine-L-tyrosine-D-citrulline-L-leucine-L-arginine-L-proline-D-alanine-amide-(C 70 H 92 ClN 17 O 14 ) having the following formula. It is a decapeptide having a terminal acid amide group. It acts by blocking the action of GnRH on the pituitary gland and thus rapidly suppresses the production and action of luteinizing hormone and follicle-stimulating hormone.

Chemical Formula

[0003] An aqueous solution of a peptide is required for parenteral administration. However, aqueous solutions of peptides such as cetrorelix are susceptible to chemical decomposition. They also tend to aggregate, thereby increasing the turbidity or cloudiness of the solution during storage.

[0004] The first commercial product was Cetrotide®. It was available as a lyophilized powder in glass vials containing 0.25 mg or 3 mg of cetrorelix. A glass prefilled syringe with 1 ml or 3 ml of sterile water for injection was provided separately and the solution was prepared only prior to injection. Thus, the first product solved the problem of degradation in aqueous solution simply by avoiding the preparation of a dosage form containing an aqueous solution that had to be stored over a long period. Instead, to avoid the problem of instability, water was removed and a lyophilized product was prepared. However, this solution to the problem has obvious demerits that (1) it is an expensive and time-consuming process, (2) the product is not immediately injectable and requires reconstitution prior to administration, and (3) the reconstituted solution is stable only for a short period. Therefore, Cetrotide® did not meet the need for an immediately injectable aqueous solution.

[0005] U.S. Patent No. 7,718,599 discloses that the aqueous solution of cetrorelix is prone to aggregation. A liquid crystal structure was observed under a polarized microscope. Gluconic acid was added to the cetrorelix acetate solution (2.5 mg / ml), whereby at a concentration of gluconic acid of less than 0.07%, the pH became 3.7 and aggregation was observed within 2 days. When the pH was 3.7 or higher, similar failures were reported. When the concentration of gluconic acid increased to 0.71% and the pH became 3.1, aggregation was observed within 12 days, indicating that the increased concentration of gluconic acid and, consequently, the decreased pH led to improvement. The drawback of this method is that the degree of solving the aggregation problem depends on the gluconic acid concentration, and the pH decreases as the gluconic acid increases. However, U.S. Patent No. 7,718,599 did not report the effect of pH on the chemical stability of cetrorelix. Furthermore, there was no formulation in which aggregation was not observed during the long-term storage stability test. U.S. Patent Application Publication No. 2013 / 0303464 discloses a ready-to-use water-soluble preparation of cetrorelix containing cetrorelix acetate, glacial acetic acid, an isotonic agent, and water for injection. The appropriate pH was illustrated by the examples where the pH was about 3. The preferred pH according to this invention was pH 2.8 - 3.5.

[0006] U.S. Patent No. 7,214,662 discloses an aqueous solution of a peptide containing cetrorelix acetate and a recommended solution for the aggregation problem. It taught that a combination of a carboxylic acid, particularly a hydroxycarboxylic acid, preferably gluconic acid, and a surfactant reduces aggregation. The use of the carboxylic acid according to U.S. Patent No. 7,214,662 resulted in a low pH such as pH 2.5 - 3. SUMMARY OF THE INVENTION

[0007] The object of the present invention is to provide a parenteral dosage form containing a sterile and stable aqueous solution of cetrorelix acetate that can be injected immediately. Another object of the present invention is to provide an injection device pre-filled with a sterile and stable aqueous solution of cetrorelix acetate. As used herein, the phrase "can be injected immediately" means a sterile and stable aqueous solution of cetrorelix acetate suitable for direct subcutaneous or intramuscular administration, that is, it can be injected immediately and does not require re-preparation or dilution before injection. More specifically, the sterile and stable aqueous solution of cetrorelix acetate dispensed into the injection device can be injected immediately, is physically stable in terms of control against aggregation or turbidity, and is chemically stable so that impurities remain low while the parenteral dosage form is stored on the shelf and until the parenteral dosage form is injected subcutaneously or intramuscularly into the patient.

[0008] The degradation of the peptide can lead to the production of other peptides and / or peptide derivatives that may have pharmacological activity. Thus, the object was more specifically to develop a suitable method for separating and quantifying individual impurities. The object was to limit the concentration of such impurities. The inventors have discovered a high performance liquid chromatography (HPLC) method that gives distinct peaks for several impurities that were previously present and not reported in the prior art. While the prior art proposed that a low pH value reduces the tendency to aggregate, the inventors have found that by using the HPLC method, in the parenteral dosage form of the present invention, a pH value of 3 to 5 is optimal for chemical stability in terms of the increase in impurity levels over time, and that the aqueous solution of cetrorelix acetate can be prepared at this elevated pH without problems of aggregation.

[0009] The novel impurity discovered by the inventors was impurity A represented by the compound of formula I below.

Chemical formula

[0010] Impurity B is characterized by having a structure represented by the compound of the following formula II. [Chemical formula]

[0011] Impurity D is characterized by having a structure represented by the compound of the following formula III. [Chemical formula]

[0012] Impurity F is characterized by having a structure represented by the compound of the following formula IV. [Chemical formula]

[0013] In the prior art, a low pH value of 3.0 was considered to be the optimal pH for stability. However, in the present invention, it has been found that at a pH value of 2.5 - 3.0 proposed by the prior art, the level of Impurity A significantly increases after storage of the solution at 25°C / 60% relative humidity.

[0014] None of the prior arts identified the compounds of formula I, II, III, IV, namely Impurities A, B, D, F, respectively.

[0015] The present invention has found that not only can a stable aqueous solution of cetrorelix acetate be prepared at pH 3 - 5 without the problem of aggregation, but also the levels of Impurity A and total impurities are well controlled, and the parenteral dosage form remains at a low concentration after storage at 25°C / 60% RH for at least 1 month, at least 2 months, at least 3 months, or at least 6 months. The parenteral dosage form can also be stored with good stability at 2 - 8°C for at least 24 months.

[0016] In one aspect, the present invention provides a parenteral dosage form comprising a stable aqueous solution, and the aqueous solution comprises the following: (i) Cetrorelix or a pharmaceutically acceptable salt thereof, and (ii) impurities of formula I in an amount less than 5% w / v of the cetrorelix base.

Chemical formula

[0017] Preferably, the parenteral dosage form contains impurities of formula I in an amount less than 4% w / v of the cetrorelix base. More preferably, the parenteral dosage form contains impurities of formula I in an amount less than 3% w / v of the cetrorelix base. More preferably, the parenteral dosage form contains impurities of formula I in an amount less than 2% w / v of the cetrorelix base. More preferably, the parenteral dosage form contains impurities of formula I in an amount less than 1% w / v of the cetrorelix base.

[0018] The parenteral dosage form further contains an osmotic agent and water for injection.

[0019] In a preferred embodiment, the present invention provides a parenteral dosage form comprising a stable aqueous solution, the aqueous solution comprising: (i) Cetrorelix or a pharmaceutically acceptable salt thereof, and (ii) impurities of formula I in an amount less than 1% w / v of the cetrorelix base.

Chemical formula

[0020] In another embodiment, the present invention provides a parenteral dosage form comprising a stable aqueous solution, the aqueous solution comprising: (i) Cetrorelix or a pharmaceutically acceptable salt thereof, and (ii) impurities of formula I in an amount less than 1% w / v of the cetrorelix base.

Chemical formula

[0021] In another embodiment, the present invention provides a parenteral dosage form comprising an immediately injectable sterile and stable aqueous solution, the aqueous solution comprising: (i) Setorelix or a pharmaceutically acceptable salt thereof, (ii) An organic acid for adjusting the pH in the range of 3 to 5, (iii) Impurity A (a decapeptide of formula I) in an amount less than 1% w / v of the setorelix base,

Chemical formula

[0022] In one embodiment, the present invention provides a parenteral dosage form comprising a sterile and stable aqueous solution that can be immediately injected, and the aqueous solution consists of: (i) Setorelix or a pharmaceutically acceptable salt thereof, (ii) An organic acid for adjusting the pH in the range of 3 to 5, (iii) Impurity A (a decapeptide of formula I) in an amount less than 1% w / v of the setorelix base,

Chemical formula

[0023] The parenteral dosage form according to the present invention, comprising a sterile and stable aqueous solution of setorelix that can be immediately injected, remains physically and chemically stable when stored at 2 - 8 °C for at least 1 month, at least 3 months, at least 6 months, at least 12 months, at least 18 months, or at least 24 months, or at room temperature (25 °C / 60% RH) for at least 1 month, at least 3 months, or at least 6 months.

[0024] A preferred embodiment of the stable parenteral dosage form can be labeled with a shelf life of at least 24 months or 24 months when stored at 2 - 8 °C. A more preferred embodiment of the parenteral dosage form can be labeled with a shelf life of at least 6 months or 6 months under storage conditions at room temperature (25 °C / 60% RH).

[0025] After storage at 2 - 8°C for at least 1 month, at least 2 months, at least 3 months, at least 6 months, at least 12 months, at least 18 months, or at least 24 months, and / or at room temperature (25°C / 60%RH) for at least 1 month, at least 2 months, at least 3 months, or at least 6 months, the concentration of the decapeptide (Impurity A) of Formula I remains within the range of 0.001% - 1.0%, preferably 0.05 - 0.5% by weight of cetrorelix base, the single largest unknown impurity remains less than 0.5% by weight of cetrorelix base, and the total impurities remain 3.5% or less by weight of cetrorelix base.

[0026] The parenteral dosage form containing the sterile aqueous solution of cetrorelix that can be immediately injected according to the present invention is physically stable and there is no aggregation, gel formation, or precipitation of the aqueous solution during the shelf life. Aggregation or gel formation can be determined by measuring the turbidity or cloudiness of the solution. It is measured in FTU units (formazin turbidity units) or NTU units (nephelometric turbidity units).

[0027] The test is carried out according to the protocol described in the European Pharmacopoeia 9.0. The solution is said to have no aggregation or gel formation when the turbidity / cloudiness value is 8 FTU / NTU or less. The higher the FTU / NTU value, the higher the turbidity and cloudiness of the solution, and vice versa. Initially, and after long - term storage of the parenteral dosage form that can be immediately injected according to the present invention at 2 - 8°C for at least 1 month, at least 2 months, at least 3 months, at least 6 months, at least 12 months, at least 18 months, or at least 24 months, and / or at room temperature (25°C / 60%RH) for at least 6 months, the NTU value remains less than 2 NTU, preferably less than 1 NTU, more preferably less than 0.5 NTU. Therefore, there is no aggregation, gel formation, or precipitation of the aqueous solution during the shelf life. Also, there is no substantial increase in the viscosity of the solution after storage.

[0028] The parenteral dosage form containing a sterile and stable aqueous solution of citalopram that can be immediately injected according to the present invention contains citalopram acetate at a concentration in the range of 0.26 mg / ml to 0.28 mg / ml, and this amount corresponds to 0.25 mg / ml of citalopram base. Preferably, citalopram acetate is present in a sterile and stable aqueous solution that can be immediately injected at a concentration corresponding to 0.25 mg / ml of citalopram base.

[0029] In one embodiment, the parenteral dosage form containing a sterile and stable aqueous solution of citalopram that can be immediately injected according to the present invention contains a pH adjuster at a concentration sufficient to adjust the pH to a range of 3 to 6.

[0030] In a preferred embodiment, the parenteral dosage form containing a sterile and stable aqueous solution of citalopram that can be immediately injected according to the present invention contains an organic acid as a pH adjuster at a concentration sufficient to adjust the pH within the range of 3 to 5, more preferably within the range of 4 to 4.5. The pH of the sterile and stable aqueous solution that can be immediately injected according to the present invention can be, for example, 3, 3.05, 3.10, 3.15, 3.20, 3.25, 3.30, 3.35, 3.40, 3.45, 3.5, 3.55, 3.60, 3.65, 3.70, 3.75, 3.80, 3.85, 3.90, 3.95, 4.00, 4.05, 4.10, 4.15, 4.20, 4.25, 4.30, 4.35, 4.40, 4.45, 4.50, 4.55, 4.60, 4.65, 4.70, 4.75, 4.80, 4.85, 4.90, 4.95, 5.00, 5.05, 5.10, 5.15, 5.20, 5.25, 5.30, 5.35, 5.40, 5.45, 5.50, 5.55 and 6, or within a range in between.

[0031] The organic acid can be selected from any parenterally acceptable organic acid that is soluble in water, but is preferably acetic acid, more preferably lactic acid. For example, lactic acid can be used in the sterile aqueous solution that can be immediately injected according to the present invention at a concentration in the range of about 0.013 mg / ml to 0.53 mg / ml, preferably in an amount in the range of about 0.033 mg / ml to about 0.53 mg / ml, and within a range in between.

[0032] According to the present invention, a sterile and stable aqueous solution of sertraline that can be immediately injected contains sertraline (base) and an organic acid in a weight ratio in the range of 50.47:1 to 19.23:1, preferably in a weight ratio in the range of about 0.47:1 to 7.57:1, more preferably in a weight ratio in the range of about 1.56:1 to 7.57:1, and in ranges intermediate thereto.

[0033] The parenteral dosage form containing the sterile and stable aqueous solution of sertraline that can be immediately injected according to the present invention contains an appropriate amount of an osmotic pressure agent or isotonic agent to adjust the osmotic pressure of the solution within the range of about 250 to 375 mOsm / kg, preferably 270 to 330 mOsm / kg. Osmotic pressure agents that may be used in the aqueous solution according to the present invention are selected from, but not limited to, mannitol, glycerol, sorbitol, sodium chloride, potassium chloride, dextrose, sucrose, and the like, and mixtures thereof.

[0034] According to a preferred embodiment, the osmotic pressure agent is mannitol and can be used in the aqueous solution in an amount in the range of about 40.0 mg / ml to 60.0 mg / ml, preferably in an amount in the range of about 50.0 mg / ml to 58.0 mg / ml. In a preferred embodiment, the osmotic pressure agent is mannitol and is used in an amount of about 55.0 mg / ml in the sterile aqueous solution that can be immediately injected.

[0035] The sterile aqueous solution that can be immediately injected of the parenteral dosage form of the present invention does not contain lactic acid in the form of a derivative of lactic acid, a polymer, or a copolymer (such as polylactic acid or a lactic acid-glycolic acid copolymer). Preferably, lactic acid is used as a sole pH adjuster. In a preferred embodiment, the sterile aqueous solution that can be immediately injected does not contain any surfactant such as Tween 80, polysorbate, poloxamer, span, etc. The sterile aqueous solution that can be immediately injected of the parenteral dosage form avoids the use of surfactants, complexing agents, preservatives, or antioxidants for solubilization or stabilization. In a particular embodiment, the solution does not contain a complexing agent such as cyclodextrin, does not contain a co-solvent such as alcohol or glycol, and also does not contain a preservative and an antioxidant.

[0036] In another aspect, the present invention provides a sterile aqueous solution of cetrorelix acetate as described above, which remains stable for at least 1 month, preferably at least 3 months, more preferably at least 6 months at a temperature of 25 °C and a relative humidity of 60%.

[0037] In yet another aspect, the present invention provides a sterile aqueous solution of cetrorelix acetate as described above, which remains stable for at least 1 month, preferably at least 3 months, more preferably at least 6 months, even more preferably at least 12 or 18 months, and most preferably at least 24 months at 2 - 8 °C.

[0038] The stable parenteral dosage form containing the sterile and stable aqueous solution of cetrorelix that can be immediately injected according to the present invention is suitable for administration by the subcutaneous or intramuscular route. The sterile and stable aqueous solution that can be immediately injected is suitable for direct subcutaneous administration, i.e., it can be immediately injected or self-administered immediately without the need for reconstitution or dilution before use. The sterile and stable aqueous solution that can be immediately injected according to the present invention does not involve lyophilization.

[0039] The stable parenteral dosage form of the present invention is suitable for self-administration, enabling the patient to self-administer a small amount of the aqueous solution subcutaneously. The amount of the sterile aqueous solution of cetrorelix that can be immediately injected filled in the storage part of the injection device ranges from about 0.5 ml to 10.0 ml, preferably from 1.0 ml to 2.0 ml, and more preferably 1.0 ml. According to one preferred embodiment, the sterile and stable aqueous solution of cetrorelix that can be immediately injected is filled in the storage part of the injection device in an amount of 1.0 ml. The parenteral dosage form according to the present invention is preferably suitable for the administration of a single dose of cetrorelix acetate. In one embodiment, the parenteral dosage form contains a filling amount of about 1.0 ml of an aqueous solution of cetrorelix acetate suitable for self-administration as a single dose. In some embodiments, the parenteral dosage form may contain an aqueous solution of cetrorelix with a filling amount of about 10.0 ml suitable for multiple-dose administration.

[0040] The injection device with a stable parenteral dosage form of the present invention can be selected from, but is not limited to, prefilled syringes, autoinjectors, etc. In a preferred embodiment, the injection device is a prefilled syringe. In another preferred embodiment, the injection device is an autoinjector such as a pen-type autoinjector. These prefilled syringes or autoinjectors are suitable for patients who require self-administration or automatic injection of a drug solution, and thus provide an easy-to-use method.

[0041] In a preferred embodiment, the injection device is a prefilled syringe. The prefilled syringe comprises the following components: a storage part, such as a barrel or a cartridge, for storing an aqueous solution; a fixed needle attached to one end of the storage part; a needle shield or a tip cap (optionally, a rigid shield covering the needle shield or the tip cap) that covers the needle and seals the opening at the needle tip; a plunger stopper at the other end of the storage part that closes and seals the aqueous solution filled in the storage part; and a plunger rod that fits into the plunger stopper and is used to push the plunger stopper together with the solution towards the needle tip during drug administration.

[0042] In another preferred embodiment, the injection device is an autoinjector. The autoinjector can have various designs. In one preferred design, the autoinjector comprises the following components: a central assembly or body portion suitable for holding a prefilled syringe, a syringe including a storage portion such as a barrel or cartridge for storing an aqueous solution, and a storage portion having a fixed needle at one end and a plunger stopper at the other end. The central body portion may have a transparent inspection window through which the solution in the storage portion can be seen. The autoinjector further comprises a front assembly having a cap portion for holding a needle shield or tip cap, which is attachable to the central assembly that covers the fixed needle and seals the needle tip opening. The autoinjector further includes a rear assembly comprising a plastic rod having a spring assembly and an activation button. During self-administration of the aqueous solution, first, the cap is removed together with the needle shield from the body portion to expose the needle, and then, after positioning the body portion of the autoinjector at the administration site, when the activation button is pressed, the plastic rod having the spring assembly is pushed towards the plunger stopper, resulting in delivery of the aqueous solution to the patient through the needle.

[0043] The storage portion may be a barrel or cartridge (e.g., the barrel of a prefilled syringe, or the cartridge of an autoinjector, etc.). It may be made of a material selected from glass, plastic, or polymeric materials. In some preferred embodiments, the storage portion is made of glass such as USP type I siliconized glass or non-pyrogenic glass material. In other embodiments, the storage portion is made of a non-glass plastic or polymeric material selected from cycloolefin polymers, cycloolefin copolymers, polyolefins, styrene-polyolefin based polymers and block copolymers, polycarbonates, etc. In one preferred embodiment, the storage portion is a non-pyrogenic glass barrel of a prefilled syringe, or a non-pyrogenic glass cartridge of an autoinjector.

[0044] In one or more embodiments, the reservoir may have a fixed needle at one end. In some other embodiments, the reservoir has no needle and has a luer lock at one end equipped for attaching a needle to the luer tip prior to use. The fixed needle may be made of stainless steel. The needle tip is shielded or covered by a needle shield or a tip cap. The reservoir containing the sterile aqueous solution of the drug is further sealed with a stopper such as a plunger stopper at the other end. These stoppers, needle shields, or tip caps provide a physical aseptic barrier against the external environment.

[0045] Preferably, the plunger stopper, the needle shield / tip cap, or the cap of the luer lock is made of non - glass components. The non - glass components may be rubber or elastomeric materials such as bromobutyl rubber, chlorobutyl rubber, USP type II rubber, natural rubber made of poly - cis - 1,4 - isoprene, styrene - butadiene rubber, etc. Other suitable materials include high - density polyethylene or low - density polyethylene or other plastic materials. In a preferred embodiment, the plunger stopper is made of bromobutyl rubber and the needle shield or tip cap is made of natural rubber. The needle shield may be further covered on the outside by a rigid shield made of polypropylene, thereby protecting the needle shield from damage and improving the removal of the needle shield before injection. The injection device assembly may have a plunger rod attached to the plunger stopper and used to push the plunger stopper towards the needle tip together with the solution during drug administration.

[0046] Preferably, the sterile and stable aqueous solution of cetrorelix that can be injected immediately is filled into the storage part of the injection device and sealed in such a manner that substantially no air remains in the upper part inside the storage part. The aqueous solution in the storage part always remains in contact with a plunger stopper made of an elastomer material or a rubber material during storage. In the case of a prefilled syringe having a fixed needle made of stainless steel, the needle is covered with a needle shield or a tip cap, and the aqueous solution remains in contact with the needle and the needle shield or the tip cap during storage.

[0047] Optionally, the injection device may be packaged or enclosed in a secondary packaging. The secondary packaging may be a blister packaging, an aluminum pouch and / or an opaque carton. Optionally, a suitable deoxidizer may be placed inside the secondary packaging.

[0048] The stability test of the parenteral dosage form is carried out by storing the dosage form at 2 - 8°C and at room temperature (25°C / 60% relative humidity). During the stability test, the sterile solution of cetrorelix that can be injected immediately remains in contact with a plunger stopper made of an elastomer rubber material and a needle shield, and a fixed needle made of stainless steel. In a preferred embodiment, the parenteral dosage form containing the sterile aqueous solution of cetrorelix according to the present invention remains physically and chemically stable when stored at 2 - 8°C for 1 year, preferably 2 years, and at room temperature (25°C, relative humidity 60%) for at least 6 months. The concentration of impurity A remains less than 1.0% by weight of the cetrorelix base after storing the filled injection device at room temperature (25°C / relative humidity 60%) for at least 6 months and at 2 - 8°C for at least 24 months. Considering a level of 1% or less, the estimated shelf life of the aqueous solution of cetrorelix determined by the calculation of impurity A by Minitab was found to be 122 months.

[0049] In one aspect, the present invention relates to a method for inhibiting an early luteinizing hormone surge in a woman undergoing a controlled ovarian stimulation method, the method comprising An injectable parenteral dosage form comprising a sterile, stable aqueous solution, the aqueous solution comprising: (i) cetrorelix or a pharmaceutically acceptable salt thereof, and (ii) an impurity of formula I in an amount less than 5% w / v of the cetrorelix base.

Chemical formula

[0050] Preferably, the stable aqueous solution comprises the impurity of formula I in an amount less than 4% w / v of the cetrorelix base. More preferably, the stable aqueous solution comprises the impurity of formula I in an amount less than 3% w / v of the cetrorelix base. More preferably, the stable aqueous solution comprises the impurity of formula I in an amount less than 2% w / v of the cetrorelix base. More preferably, the stable aqueous solution comprises the impurity of formula I in an amount less than 1% w / v of the cetrorelix base.

[0051] The stable aqueous solution further comprises an osmotic agent and water for injection.

[0052] In one aspect, the present invention relates to a method of inhibiting an early luteinizing hormone surge in a female undergoing a controlled ovarian stimulation method, the method comprising a parenteral dosage form comprising a sterile, stable aqueous solution that is immediately injectable, the aqueous solution comprising: An injectable parenteral dosage form comprising a sterile, stable aqueous solution, the aqueous solution comprising: (i) cetrorelix or a pharmaceutically acceptable salt thereof, (ii) impurity A (a decapeptide of formula I) in an amount less than 1% w / v of the cetrorelix base.

Chemical formula

[0053] In one aspect, the present invention relates to a method of inhibiting an early luteinizing hormone surge in a female undergoing a controlled ovarian stimulation method, the method comprising a parenteral dosage form comprising a sterile, stable aqueous solution that is immediately injectable, the aqueous solution comprising: (i) cetrorelix or a pharmaceutically acceptable salt thereof, (ii) Cetrorelix base in an amount of less than 1% w / v of impurity A (the decapeptide of formula I).

Chem.

[0054] In a preferred embodiment, the present invention relates to a method for inhibiting premature luteinizing hormone surge in women undergoing controlled ovarian stimulation, the method comprising a parenteral dosage form comprising a sterile, stable aqueous solution that can be injected immediately, the aqueous solution comprising: (i) Cetrorelix or a pharmaceutically acceptable salt thereof, (ii) an organic acid for adjusting the pH to a range of 3 to 5, (iii) Cetrorelix base in an amount of less than 1% w / v of impurity A (the decapeptide of formula I),

Chem.

[0055] In another embodiment, the present disclosure provides a decapeptide of formula I.

Chem.

[0056] Since this compound is an impurity of the cetrorelix solution, it is referred to herein as "impurity A".

[0057] The present disclosure also provides a composition comprising the decapeptide of formula I.

Chem.

[0058] In another embodiment, the present disclosure provides a process for identifying the decapeptide of formula I by HPLC analysis, the process comprising: a) injecting a diluent comprising water, acetonitrile, and formic acid into a chromatographic system, b) Injecting a system suitability solution containing cetrorelix acetate, a diluent, and an impurity stock solution, and recording a chromatogram; c) Injecting a standard solution containing cetrorelix acetate and a diluent into the chromatograph system; d) Injecting a sample containing an aqueous solution of cetrorelix acetate and a placebo preparation into the chromatograph system; e) Determining the relative retention times and relative response factors of the impurities and cetrorelix acetate with respect to cetrorelix acetate.

[0059] The present disclosure also provides a decapeptide of Formula I identified by HPLC analysis, and the process comprises 1. Injecting a diluent containing water, acetonitrile, and formic acid into the chromatograph system; 2. Injecting a system suitability solution containing cetrorelix acetate, a diluent, and an impurity stock solution, and recording a chromatogram; 3. Injecting a standard solution containing cetrorelix acetate and a diluent into the chromatograph system; 4. Injecting a sample containing an aqueous solution of cetrorelix acetate and a placebo preparation into the chromatograph system; 5. Determining the relative retention times and relative response factors of the impurities and cetrorelix acetate with respect to cetrorelix acetate.

[0060] Hereinafter, the present invention will be described more specifically by way of examples. The examples are not intended to limit the scope of the present invention, but are merely used for illustration.

[0061] [Example 1A] Identification of Degradation Products To investigate the degradation of setrorelix, peptide-related substances of setrorelix were prepared by well-known techniques of solid-phase peptide synthesis. The synthesis starts sequentially from the C-terminal amino acid on the resin and involves coupling one amino acid at a time. The synthesis of the peptide chain was carried out using fluorenylmethyloxycarbonyl (Fmoc) / tert-butyl (Fmoc / tBu) with N,N'-diisopropylcarbodiimide (DIPC) as the coupling reagent. The Fmoc group was removed by treatment with 20% piperidine in dimethylformamide. The peptide formed on the resin was finally cleaved using trifluoroacetic acid to obtain the related substances, which were further purified by reverse-phase high-performance liquid chromatography (RP-HPLC) on a C18 Silica column using a gradient of acetonitrile / water containing 0.1% trifluoroacetic acid. The purified peptide-related substances were lyophilized to obtain a pure solid form. The structures of these related substances were characterized by Proton NMR, Carbon NMR, mass spectrometry, and elemental analysis and were named Impurity A, B, D, F.

[0062] Impurity - A: Ac - 2 - D - Nal - 4 - Cl - D - Phe - 3 - D - Pal - Ser - Tyr - D - Cit - Leu - Arg - Pro - D - Ala - OH (detailed structure depicted as the compound of formula I),

[0063] Impurity - B: 2 - D - Nal - 4 - Cl - D - Phe - 3 - D - Pal - Ser - Tyr - D - Cit - leu - Arg - Pro - D - Ala - NH2 (detailed structure depicted as the compound of formula II),

[0064] Impurity - D: Ac - 2 - D - Nal - 4 - Cl - D - Phe - 3 - D - Pal - Ser - Tyr - D - Cit - Leu - OH (detailed structure depicted as the compound of formula III), and

[0065] Impurity - F: Ac - 2 - D - Nal - 4 - Cl - D - Phe - 3 - D - Pal - Ser - Tyr - D - Cit - Leu - Arg - Pro - OH (detailed structure depicted as the compound of formula IV).

[0066] The degradation peaks separated on the HPLC column were identified as these compounds based on the relative retention times of the compounds. Details of the HPLC method are provided in Example 1B below.

[0067] [Example 1B] Cetrorelix, and the impurities identified from the aqueous solution sample, namely Impurity A, Impurity B, Impurity D, and Impurity F, were separated on a reversed-phase (C-18) column using a gradient method (column: X-Select CHS C18, (150×4.6) mm, 2.5 μ (manufactured by Waters (Ireland), part number: 186006729)) and detected and quantified by ultraviolet spectroscopy at a wavelength of 225 nm. The mobile phase was run at flow rates of 0.7 ml / min and 1.0 ml / min. The run time of the chromatogram was 150 minutes.

[0068] Details of the mobile phase: Mobile phase A: The following buffer solution and a mixture of acetonitrile and tetrahydrofuran (ratio 700:280:20) were degassed by sonication.

[0069] Mobile phase B: The following buffer solution and a mixture of acetonitrile and tetrahydrofuran (ratio 500:480:20) were degassed by sonication.

[0070] Buffer solution: 2.5 g of ammonium dihydrogen orthophosphate and 0.75 g of sodium 1-octanesulfate were placed in 1000 ml of water, and the pH was adjusted to 8.0 ± 0.05 using triethylamine.

[0071] Diluent: A mixture of water, acetonitrile, and formic acid (ratio 700:300:1).

[0072] [Table 1]

[0073] Preparation of Stock Solution of Impurities : 3.125 mg each of impurity A, impurity B, impurity D, and impurity F was placed in a 50-ml volumetric flask, dissolved in approximately 5 ml of diluent by sonication, and then the volume was made up using the diluent.

[0074] Preparation of System Suitability Solution: This was prepared by weighing approximately 12.5 mg of sertraline acetate standard reagent into a 100-ml volumetric flask, dissolving it in approximately 50 ml of diluent by sonication, then adding approximately 2 ml of the impurity stock solution, and making up the volume using the diluent.

[0075] Preparation of Standard Solution of Setrorelix Acetate: The standard solution of sertraline acetate was prepared by weighing 20 mg of sertraline acetate standard reagent, transferring it to a 250-ml volumetric flask, dissolving it in approximately 50 ml of diluent by sonication, and making up the volume with the diluent. 2 ml of this solution was transferred to a 250-ml volumetric flask, and the volume was made up to the mark using the diluent while mixing.

[0076] Preparation of Test Solution : The aqueous sertraline acetate solution (prepared according to the above-mentioned example) from about 10 prefilled syringes of the sample to be tested was mixed in a container. The solution contains sertraline acetate, organic acid, osmotic agent, and water for injection. Exactly about 5.0 ml of this solution was transferred to a 10-ml volumetric flask, approximately 3 ml of diluent was added, and the solution was sonicated for 5 minutes while shaking intermittently. The volume was made up using the diluent while mixing.

[0077] The placebo was prepared by transferring exactly about 5.0 ml of placebo solution into a 10 ml volumetric flask, adding about 3 ml of diluent, and sonicating for 5 minutes with intermediate shaking. The volume was made up with diluent while mixing. 50 microliters of an injection of the diluent, which was the blank sample, was injected into the chromatographic system. Subsequently, the system suitability solution was injected and the chromatogram was recorded. The resolution between impurity D and impurity F was 2.0 or more. Subsequently, six replicates of the standard solution were injected. Thereafter, the sample and the placebo preparation were injected into the chromatographic system.

[0078] Table 2 shows the relative retention times and relative response factors of cetrorelix acetate and impurities A, B, D, and F with respect to cetrorelix acetate.

[0079]

Table 2

[0080] The percentages of impurities A, B, D, F, and unknown impurities were calculated by excluding the peaks from the diluent and placebo. The sum of all known and unknown impurities resulted in the total impurity %.

[0081] The % of the identified impurities (A, B, D, F) was calculated by the following formula:

Equation

[0082] Wherein, A1 = Peak response of each known impurity in the chromatogram of the test preparation, AS = Average peak response of cetrorelix in the chromatogram of the standard preparation, WS = Weight (mg) of the cetrorelix acetate standard reagent V = Volume (mL) of the sample taken P = % of the potency of the cetrorelix standard reagent (as is), LC = Label claim of cetrorelix (mg / ml) (0.25 mg / ml), RRF = Relative response factor of each impurity

[0083] The percentage of unknown impurities was calculated by the following formula.

Number

[0084] In the formula, A1 = Peak response of each unknown impurity in the chromatogram of the test preparation, AS = Average peak response of sertraline in the chromatogram of the standard preparation, WS = Weight (mg) of sertraline acetate standard reagent V = Amount (mL) of the sample taken P = % Potency of sertraline standard reagent (as is), LC = Label claim of sertraline (mg / ml) (0.25 mg / ml) Total impurities (%) = Sum of known impurities % and unknown impurities %.

[0085]

Table 3

[0086] Preparation method: Water for injection was collected in a container at a temperature of 2°C to 8°C. Mannitol was added and gradually dissolved in the water for injection while stirring until a clear solution was obtained. Cetrorelix acetate was added thereto and gradually dissolved while stirring. The pH of the solution was checked and adjusted to the pH as described in Table 3 for each example and comparative example of the present invention using a specified amount (quantity) of 0.1% w / v lactic acid solution. Water for injection was added to make a predetermined amount. The solution was stirred for 10 to 15 minutes. The solution of the example was aseptically filtered through a layer of a 0.2 micron membrane filter. The solution was aseptically filled into the storage part of the injection device (i.e., inside the barrel of a 1 ml glass syringe with a filling volume of 1.1 ml). The fixed needle in the barrel was blocked by an elastomeric needle shield covered with a hard cap before filling. After filling, the glass syringe (barrel) was blocked with a plunger stopper by vacuum tightening so that substantially no air remained at the upper part inside the syringe. The aqueous solution remained in contact with the rubber plunger stopper, the stainless steel fixed needle, and the natural rubber needle shield after storage.

[0087] For the immediately injectable aqueous solutions of Examples 1 to 9 and Comparative Examples 10 to 14, chemical analysis was performed at different stages. First, the % assay of cetrorelix in the solution before and after filtration was analyzed by the HPLC method described above. The change in the chemical assay % before and after filtration was determined.

[0088] Next, a storage stability test was conducted on the solution of the example contained in the glass syringe. At the initial time point, and after storage at room temperature (25°C / 60% relative humidity) and at different time points at 2°C to 8°C, the % assay, the levels of degradation products such as the compounds of Formulas I, II, III, and IV, and the levels of unknown impurities and total impurities in the filtered solution filled in the parenteral dosage form injection device were determined using the high performance liquid chromatography method described above.

[0089] After six months of storage at room temperature, it was found that the levels of impurities A and B, the single largest unknown impurity, and the total impurities either remained unchanged or changed only slightly. Based on this data, the parenteral dosage form of the present invention is expected to be chemically stable over a long period of time. The solution was found not to exhibit problems of aggregation or an increase in viscosity when prepared and when filled into and stored in the syringe device. The data also demonstrated that cetrorelix was not absorbed or adsorbed onto or within the components of the device (e.g., the rubber stopper that was in contact with the solution during storage).

[0090] The stability results for the stable parenteral dosage form at 25°C / 60% RH and 2 - 8°C according to the present invention are provided in Tables 4 and 5 below.

[0091] [Table 4]

[0092] [Table 5]

[0093] [Table 6]

[0094] After storage at 25°C / 60% RH and 2 - 8°C, the stability results for additional intermediate pH ranges at different time points are presented in Table 7 below.

[0095] [Table 7]

[0096] [Table 8]

[0097] Each mL contains cetrorelix acetate corresponding to 0.25 Mg of cetrorelix, 54.8 mg of mannitol, an appropriate amount of lactic acid for adjusting the pH to 5.0, and an appropriate amount of water for injection to make 1 mL.

[0098]

Table 9

[0099]

Table 10

[0100]

Table 11

[0101] An aqueous solution of cetrorelix acetate was prepared according to the disclosure of U.S. Patent Application Publication No. 2013 / 0303464 (Patel et al.). The composition is shown in Table 12 below.

[0102]

Table 12

[0103] Preparation method: Water for injection was collected in a container at a temperature of 2°C to 8°C. Mannitol was added and gradually dissolved in the water for injection while stirring until a clear solution was obtained. Cetrorelix acetate was added thereto and gradually dissolved while stirring. Next, glacial acetic acid was added to adjust the pH of the solution to approximately 3.0. Water for injection was added to make a predetermined amount. The solution was stirred for 10 to 15 minutes and then aseptically filtered through a layer of a 0.2 μm membrane filter (Optiskale 47 capsule, polyethersulfone membrane filter, manufactured by Millipore). The solution was aseptically filled into the storage part of the injection device (i.e., inside the barrel of a 1 ml glass syringe with a filling volume of 1.1 ml). The fixed needle inside the barrel was blocked by an elastomeric needle shield covered with a rigid cap before filling. After filling, the glass syringe (barrel) was blocked with a plunger stopper by vacuum tightening so that substantially no air remained at the upper part inside the syringe. The aqueous solution remained in contact with the rubber plunger stopper, the stainless-steel fixed needle, and the natural rubber needle shield after storage.

[0104] A storage stability test was conducted on the solution of this comparative example (Comparative Example 2) filled in a glass syringe. The levels of impurity A, impurity B, and total impurities in the solution were analyzed by high-performance liquid chromatography method initially and after storage at room temperature (25°C / 60% relative humidity). The results are provided in Table 13 below.

[0105]

Table 13

[0106] It was observed that the solution of cetrorelix acetate of US Patent Application Publication No. 2013 / 0303464 (comparative object) showed a significant increase in the levels of impurity A and total impurities after storage at room temperature. In particular, the level of impurity A, which is a degradation impurity, significantly increased in 6 months and increased to 1.77% by weight of cetrorelix. Also, the level of total impurities increased to 2.83% by weight of cetrorelix in 6 months.

[0107] In contrast, the parenteral dosage form containing the immediately injectable aqueous solution of cetrorelix acetate of the present invention remains stable over a long period of time at room temperature, whereby substantially no decomposition or increase in the level of impurity A, other impurities, or total impurities occurs after storage, and the solution has an estimated shelf life of more than 24 months.

Claims

1. A parenteral pharmaceutical composition comprising a sterile and stable aqueous solution that can be immediately injected, wherein the aqueous solution comprises: i) cetrorelix or a pharmaceutically acceptable salt thereof in an amount of 0.25 mg / mL; ii) lactic acid in a concentration sufficient to adjust the pH within the range of 4.00 to 5.00; iii) impurity A, which is a decapeptide of formula I, in an amount less than 1% w / v of the cetrorelix base; 【Chemical 1】 iv) an osmotic agent, and v) water for injection. A parenteral pharmaceutical composition comprising the above components.

2. The parenteral pharmaceutical composition according to claim 1, wherein the osmotic agent is present in an amount sufficient to bring the osmolality of the solution within the range of 250 to 375 mOsm / Kg.

3. The parenteral pharmaceutical composition according to claim 1, wherein the sterile and stable aqueous solution that can be immediately injected is present in the storage part of the injection device.

4. The parenteral pharmaceutical composition according to claim 3, wherein the injection device is a prefilled syringe.

5. The parenteral pharmaceutical composition according to claim 3, wherein the injection device is an autoinjector.

6. The parenteral pharmaceutical composition according to claim 3, wherein the injection device is a pen-type autoinjector.

7. The parenteral pharmaceutical composition according to claim 1, wherein the stable aqueous solution is stable for at least 1 month at a temperature of 25°C and a relative humidity of 60%.

8. The parenteral pharmaceutical composition according to claim 1, wherein the stable aqueous solution is stable for at least 3 months at a temperature of 25°C and a relative humidity of 60%.

9. The parenteral pharmaceutical composition according to claim 1, wherein the stable aqueous solution is stable for at least 6 months at a temperature of 25°C and a relative humidity of 60%.

10. The parenteral pharmaceutical composition according to claim 1, which is suitable for subcutaneous use.

11. The parenteral pharmaceutical composition according to claim 1, which is suitable for intramuscular use.

12. The parenteral pharmaceutical composition according to claim 1, which is used for inhibiting premature luteinizing hormone surge in women undergoing controlled ovarian stimulation.

13. The parenteral pharmaceutical composition according to claim 1, wherein after storage at 25°C and 60% relative humidity for 6 months, the aqueous solution contains impurity A in an amount less than 0.5% w / v of the cetrorelix base.

Images