DESC:FIELD OF THE INVENTION
The present invention is related to the field of pharmaceutical formulation technology. More particularly, the present invention is directed to the aqueous solutions of small and medium size peptides such as vasopressin analogs, for example, desmopressin or its salt for intravenous or subcutaneous administration. It is a well-known fact that peptides are less stable in aqueous solutions and must therefore be kept under refrigerated conditions. So far, no room temperature stable, having extended shelf life aqueous solutions of desmopressin have been made available or explored. In an attempt, therefore, the present invention intends to provide room temperature stable desmopressin compositions having extended shelf life, which are more advantageous over marketed or known compositions having refrigerated storage conditions.

BACKGROUND OF THE INVENTION
Desmopressin acetate, also known and hereinafter may referred to as DDAVP (1-deamino-8-D-arginine vasopressin) is a synthetic analogue of the natural pituitary hormone 8-arginine vasopressin (ADH), an antidiuretic hormone affecting renal water conservation. Chemically, DDAVP can be described as 1-(3-mercaptopropionic acid)-8-D-arginine vasopressin monoacetate. DDAVP can be administered through various routes of administration, viz. oral, nasal, sublingual, intravenous etc. and so far, approved in the dosage forms, such as, tablet, spray, solution, injectable etc. Amongst which, DDAVP injection, 4 mcg/mL, is provided as a sterile, aqueous solution for injection. DDAVP injection contains desmopressin acetate (salt) trihydrate having empirical formula C46H64N14O12S2.C2H4O2.3H2O and molecular weight 1183.34. Desmopressin acetate trihydrate has structural formula as follows:

Each mL of DDAVP Injection provides: 4 mcg desmopressin acetate, 9 mg sodium chloride and hydrochloric acid to adjust pH to 4.0. DDAVP Injection is available in two presentations: in 1 mL ampoule and in 10 mL vial. The 10 mL vial contains 5 mg/mL chlorobutanol as a preservative. One mL (4 mcg) of DDAVP solution has an antidiuretic activity of about 16 IU; 1 mcg of DDAVP is equivalent to 4 IU. DDAVP has been shown to be more potent than arginine vasopressin in increasing plasma levels of factor VIII activity in patients with hemophilia and von Willebrand’s disease Type I.

DDAVP Injection 4 mcg/mL is indicated for patients with hemophilia A with factor VIII coagulant activity levels greater than 5%. DDAVP Injection 4 mcg/mL is also indicated for patients with mild to moderate classic von Willebrand’s disease (Type I) with factor VIII levels greater than 5%. DDAVP Injection 4 mcg/mL is indicated as antidiuretic replacement therapy in the management of central (cranial) diabetes insipidus and for the management of the temporary polyuria and polydipsia following head trauma or surgery in the pituitary region.

DDAVP is also available as an intranasal preparation. However, this means of delivery can be compromised by a variety of factors that can make nasal insufflation ineffective or inappropriate. These include poor intranasal absorption, nasal congestion and blockage, nasal discharge, atrophy of nasal mucosa, and severe atrophic rhinitis. Intranasal delivery may be inappropriate where there is an impaired level of consciousness. In addition, cranial surgical procedures, such as transsphenoidal hypophysectomy, create situations where an alternative route of administration is needed as in cases of nasal packing or recovery from surgery.

For the treatment of Hemophilia A and von Willebrand’s Disease (Type I), DDAVP Injection 4 mcg/mL is administered as an intravenous infusion at a dose of 0.3 mcg DDAVP/kg body weight diluted in sterile physiological saline and infused slowly over 15 to 30 minutes. In adults and children weighing more than 10 kg, 50 mL of diluent is recommended; in children weighing 10 kg or less, 10 mL of diluent is recommended. If DDAVP Injection 4 mcg/mL is used preoperatively, it should be administered 30 minutes prior to the scheduled procedure.

For the treatment of Diabetes Insipidus, DDAVP Injection is administered subcutaneously or by direct intravenous injection. The usual dosage range in adults is 0.5 mL (2.0 mcg) to 1 mL (4.0 mcg) daily, administered intravenously or subcutaneously, usually in two divided doses. The morning and evening doses should be separately adjusted for an adequate diurnal rhythm of water turnover. For patients who have been controlled on intranasal DDAVP and who must be switched to the injection form, either because of poor intranasal absorption or because of the need for surgery, the comparable antidiuretic dose of the injection is about one-tenth the intranasal dose.

DDAVP Injection 4 mcg/mL is available as a sterile solution in cartons of ten 1 mL single-dose ampules and in 10 mL multiple-dose vials, each containing 4 mcg DDAVP per mL. DDAVP Injection must be stored refrigerated 2°C to 8°C.

For long, it’s been known that, a substantial number of biologically active peptides, their derivatives and analogs are therapeutically useful. For various reasons they are often administered in the form of aqueous compositions, that is, sterile aqueous solutions containing a known amount of peptide. The biological activity of the peptides to be administered is often extremely high. Thus, only very small amounts of peptide are needed for a single does. Such dilute aqueous peptide solutions in general are not stable at room temperature for longer periods, even if kept in sealed containers. Desmospressin or its salt is such a peptide. Its aqueous solution has to be stored at a temperature not exceeding 8°C. Storage at higher temperatures such as, for instance, room temperature, results in the degradation of desmopressin by hydrolytic and/or oxidative processes which are not blocked by the addition of a preservative, such as chlorobutanol (1,1,1-trichloro-2-methylpropan-2-ol). However, chlorobutanol effectively protects desmopressin against microbial attack (United States Patent No. 5,482,931 (Ferring AB), incorporated herein by reference in its entirety, at column 1, lines 25-38).

Another problem with dilute aqueous solutions of peptides is the adsorption of minute amounts of peptide to the walls of the container in which the solution is kept. Since such peptide solutions are usually very dilute, adsorption of even minor amounts may substantially reduce the amount of peptide available for administration (United States Patent No. 5,482,931, at column 1, lines 39-44).

Thus, it was an object of the invention disclosed in the United States Patent No. 5,482,931 to overcome the stability and storage problems associated with known aqueous solutions of small and medium size peptides, particularly of aqueous solutions containing desmopressin and to provide a stabilized aqueous solution containing a peptide for nasal, oral or parenteral administration which can conveniently be stored at room temperature for extended periods of time, for instance, one year, without risking partial or total degradation or microbial contamination of the peptide contained therein (United States Patent No. 5,482,931, at column 2, lines 11-21).

To achieve its abovementioned objective, United States Patent No. 5,482,931 provides an aqueous composition, which contains a buffer, a quaternary amine preservative or disinfectant and an osmotic pressure-controlling agent. According to the ‘931 patent, the quaternary amine preservative or disinfectant selectively used have, in addition to their namesake functions, the unexpected ability to prevent adsorption of small and medium size peptide components from adhering to container walls, particularly walls of containers made of polymeric materials.

According to the ‘931 patent, it is preferred for the buffer to be capable of maintaining a pH of between 4.0 and 6.0. Especially preferred is a pH of about 5.0. The buffer used is acetic acid/sodium acetate. According to the ‘931 patent, it is preferred for the solution to contain citrate and/or phosphate buffer. Preferred buffer systems according to the ‘931 patent are citric acid/disodium hydrogen phosphate, sodium dihydrogen phosphate/disodium hydrogen phosphate, and citric acid/sodium citrate. Specifically preferred is a buffer comprising: citrate-phosphate-sodium ions in a molar ratio of from about 1:3:3 to about 1:1:2.

According to the ‘931 patent, it is preferred for the quaternary amine preservative or disinfectant to be benzalkonium chloride, (NR1R2R3R4)+Cl-; where R1, R2=methyl, R3=benzyl, R4=C8H17 to C18H37. The composition according to the ‘931 patent preferably contains the quaternary amine preservative or disinfectant in a concentration from about 0.05 to about 0.2 mg per ml. Particularly preferred is a concentration of about 0.1 mg per ml. According to the ‘931 patent, it is preferred for the osmotic pressure-controlling agent to be sodium chloride. Per ‘931 patent, the buffer components also contribute substantially to osmotic pressure control.

The ‘931 patent prepared five test compositions containing desmopressin acetate for nasal spray or drop compositions containing 0.1 mg benzalkonium chloride, 10 mg benzyl alcohol, 0.8 mg methyl paraben, 0.2 mg propyl paraben and 5 mg chlorobutanol and tested them for their stability by detecting peptide degradation. According to the ‘931 patent, the composition containing chlorobutanol was the least stable amongst others and compositions containing benzalkonium chloride demonstrated the ability to be stored and used for extensive periods without refrigeration.

However, it is pertinent to note that the ‘931 patent does not teach preparation of room temperature stable desmopressin aqueous compositions for intravenous or subcutaneous administration. Nor does the ‘931 patent suggest whether the nasal compositions prepared therein can be used for intravenous or subcutaneous administration.

Another United States Patent No. 6,949,509 (Patents Exploitation Company B.V.), incorporated herein by reference in its entirety, teaches “preservative free” desmopressin compositions. The inventors of the ‘509 patent found that the desmopressin compositions which are free from preservatives are suitably stable (as far as degradation is concerned) and do not show the problem of the adsorption of the active principle by the walls of the container. According to the ‘509 patent, the term “preservatives”, embraces all those additives, which preserve the peptide drug’s titre in the pharmaceutical solution and thus prevent losses of the solution’s potency and/or activity. In particular, the term “preservatives” embraces both, degradation inhibitors (like antioxidants or antimicrobial additives) as well as adsorption inhibitors (preventing adsorption of the active principle onto container walls). Though not explicitly mentioned, it seems that the compositions of the ‘509 patent are nasal compositions and are meant for nasal administration. Thus, the ‘509 patent also, does not teach preparation of room temperature stable desmopressin aqueous compositions for intravenous or subcutaneous administration. Nor does the ‘509 patent suggest whether the compositions prepared therein can be used for intravenous or subcutaneous administration.

United States Patent Application Publication No. 2003/0216302 (Sun Pharmaceutical Industries Limited) teaches a stable aqueous composition comprising desmopressin or its other pharmaceutically acceptable salts in a pharmaceutically acceptable carrier, wherein the carrier comprises a buffering agent, a parahydroxybenzoate preservative, and a cosolvent. According to the ‘302 publication, preservative efficacy of desmopressin aqueous compositions containing a parahydroxybenzoate preservative is improved with the use of cosolvents. However, the compositions taught in the ‘302 publication are nasal compositions and the ‘302 publication does not teach preparation of room temperature stable desmopressin aqueous compositions for intravenous or subcutaneous administration.

The patient information leaflets available for DDAVP Injection (NDA#018938) on the official website of the United States Food and Drug Administration (USFDA), drugs@FDA reveal that three United States Patent Nos. 5,500,413; 5,596,078 & 5,763,407 were identified by the then Applicant Holder-Aventis Pharma which may be related to DDAVP Injection. However, all these three United States Patents are directed to preparation of desmopressin and not injectable compositions of desmopressin.

The literature survey on the desmopressin parenteral dosage forms, especially intravenous aqueous compositions of desmopressin reveals that, very less or almost negligible efforts have been made in the direction of preparing room temperature stable desmopressin compositions having extended shelf life. Where, abundant amount of literature is available for oral, nasal and sublingual dosage forms of desmopressin, it seems that scientists have not explored preparation of room temperature stable formulations of desmopressin. Desmopressin seems to have approved prior to January 1982 and desmopressin in the form of injection (DDAVP Injection) seems to have first approved in March 1984. Since then, no room temperature stable desmopressin compositions for intravenous or subcutaneous administration are available in the market. Hence, looking at the long felt unmet need still existing in the art, the inventors of the present invention have attempted to prepare room temperature stable aqueous compositions of desmopressin. And to their surprise, they found that desmopressin acetate may be stabilized in aqueous solutions when stored at room temperature for prolonged period of time. Needless to say, room temperature stable formulations are always advantageous from preparation, storage and logistic point of view. The room temperature stable product does not require be storing and shipping at a controlled temperature (i.e. 2-8 ° C). It also does not require cold chain transport. It requires less care to be taken as compared to refrigerated formulations.

The room temperature stable desmopressin compositions for intravenous or subcutaneous administration of the present invention comprise desmopressin or its salt as an active ingredient and one or more additives/excipients selected from the group of antioxidants, pH adjusting agents, osmolality agents/osmotic pressure-controlling agents and preservatives. Without intending to be bound by any theory, it is believed that an antioxidant helps in preventing and/or slowing down the degradation of the active ingredient in the formulation as diluted aqueous solution and thus helps achieve room temperature stable composition for a prolonged time. The compositions of the present invention may optionally comprise one or more additives/excipients selected from buffering agents, cosolvents and chelating agents. However, the scope of the present invention is not limited to stable desmopressin compositions and the present invention also intends to provide compositions of other peptides as well which may be stabilized in aqueous solutions using the technology disclosed herein.

OBJECTS OF THE INVENTION
Thus, it is an object of the present invention to overcome the stability and storage problems associated with aqueous compositions of peptides, especially small and medium size peptides, particularly of aqueous compositions containing desmopressin or its salt.

Another object of the present invention is to provide a stabilized aqueous composition comprising desmopressin for intravenous or subcutaneous administration, which can be conveniently stored at room temperature for extended periods of time, for instance, at least one year or more, without risking partial or total degradation and/or microbial contamination of the peptide contained therein.

A further object of the present invention is to protect the peptide, desmopressin or its salt, in the solution from adhering to the walls of the container without using extraneous additives specifically designed for that purpose.

A yet another object of the present invention is to provide an aqueous composition for intravenous or subcutaneous administration for the management of diseases and abnormal conditions, which are mitigated by administration of desmopressin or its salt.
A yet another object of the present invention is also to provide processes for the preparation of stable desmopressin compositions of the present invention.

A further object of the present invention is to provide ready-to-use and/or ready-to-dilute solutions of desmopressin.

DETAILED DESCRIPTION OF THE INVENTION
A remarkable number of peptides, derivatives and analogues thereof are known in the therapy. They are often endowed with an utterly powerful biologic activity, therefore only very small amounts are required for therapeutic goals. Among these, small and medium size peptides, preferably small or medium size cyclic peptides, more preferably those containing one or more sulfur atoms within the cyclus, and most preferably those containing at least two sulfur atoms within the cyclus, such as, for example, analogues and derivatives of oxytocin and vasopressin, such as desmopressin (termed 1-deamino-8-D-arginin-vasopressin or 1-(3-mercaptopropanoic acid)-8-D-argininevasopressin), a powerful antidiuretic, useful in the treatment of urinary disorders associated to, for example, insipidus diabetes and nocturnal enuresis.

One of the problems arising with the peptide drugs, especially those containing easily oxidizable sulfur bonds or sulfur bridges, is the easy degradation of their aqueous solutions.

A further problem often encountered with the preparation of pharmaceutically acceptable solutions of small and medium size peptides is a seeming loss of titre in time, which is due to ongoing adsorption of the peptide drug on the surface of the container material, thus entailing a considerable loss of potency and/or activity of the pharmaceutical composition. Such adsorption problem of peptide drugs is well-known in the pharmaceutical arts.

The present invention is an aqueous composition for intravenous or subcutaneous administration of peptides, especially small and medium-size peptides, particularly desmopressin or its salt, which can maintain stability over time at room temperature. The solution contains an antioxidant, a preservative or disinfectant and an osmotic pressure-controlling agent/osmolality agent with the optional presence of a pH adjusting agent and/or a buffering agent. The solution may further comprise one or more additives selected from chelating agents and cosolvents.

Some of the preservatives or disinfectants, for example, the quaternary amine, used in the present invention may have, in addition to their namesake functions, the ability to prevent adsorption of desmopressin components from adhering to container walls, particularly walls of containers made of polymeric or glass materials.

No particular limitation is imposed on the peptide for use in the composition according to the present invention insofar as it is a peptide having pharmacological effects. Its specific examples can include calcitonin, insulin, proinsulins, epidermal growth factors, growth hormones, somatomedin C, somatostatin, granulocyte macrophage colony-stimulating factor, colony-stimulating factors, erythropoietin, interferons, interleukins, atrial natriuretic peptides, parathyroid hormones, superoxide dismutases, tissue plasminogen activators, antithrombins, blood coagulation-factor, blood coagulation-factor, protein C, hirudine, hepatitis vaccine, endorphins, ACTH-releasing hormone, neurotensin, angiotensin, transferrin, endothelin, vasopressin, desmopressin, terlipressin, atosiban, carbetocin, luteinizing hormone, luteinizing hormone-releasing hormone, triptorelin, prolactin, glucagon, gastrin, secretin, urokinase, vasoactive intestinal polypeptide and the like. However, it is preferred for the peptide or peptide analog to be oxytocin or vasopressin, or their analogs and derivatives, such as desmopressin (1-(3-mercaptopropanic acid)-8-D-arginine-vasopressin), terlipressin (N-alpha-triglycyl-8-lysine)-vasopressin), atosiban ((Mpa1, D-Tyr(Et)2, Thr4, Orn8)-oxytocin), carbetocin ((1-desamino-1-monocarba-2(0-methyl)-tyrosine)-oxytocin), and the like. The most preferred peptide is desmopressin or its other pharmaceutically acceptable salts, which are used in the management of various medical conditions like irregular urination or diurea, particularly those, associated with diabetes insipidus and nocturnal enuresis.

When used in the compositions of the present invention, it is preferred for the pH adjusting agent(s) and/or buffer(s) of the present invention to be capable of maintaining a pH of between about 3.5 and about 6.5. Especially, preferred is a pH between about 4.0 and about 6.5.
Antioxidants can be compounds that can reduce a drug that has been oxidized, or compounds that are more readily oxidized than the agents they are to protect (oxygen scavengers). Mixtures of chelating agents and antioxidants are often used because there appears to be a synergistic effect. This occurs because many of the agents act at differing steps in the oxidative process. The antioxidants when used in the compositions of the present invention include, but are not limited to, amino acids, butylated hydroxytoluene, butylated hydroxyanisole, tert-butyl-hydroquinone, 4-hydroxymethyl-2, 6-di-tert-butylphenol, 2, 4, 5- trihydroxybutyrophenone, alkylgallates, propyl gallate, octyl gallate, dodecyl gallate, ethoxyquin, gallic acid, nordihydroguaiaretic acid, glycine, ascorbic acid, fatty acid esters of ascorbic acid such as ascorbyl palmitate and ascorbyl stearate, and salts of ascorbic acid such as sodium, calcium, or potassium ascorbate; erythorbic acid, L-carnitine, monothioglycerol, acetyl L-carnitine, thioglycolic acid, N-acetyl cysteine, cysteine, glutathione, methionine, tartaric acid, citric acid, fumaric acid, glycolic acid, oxalic acid, succinic acid, ellagic acid, malic acid, maleic acid, tocopherols such as, but not limited to, delta tocopherol, alpha tocopherol; lipoic acid, thiolated polymers such as, but not limited to, polymethacrylic-SH, carboxy methylcellulose-cysteine, polycarbophil-cysteine, beta-carotene, carotenoids, flavonoids, flavones, isoflavones, flavanones, catechins, anthocyanidins, chalcones, sulfites, including but not limited to potassium sulfite, sodium metabisulfite, sodium sulfite, sodium thiosulfate and sodium bisulfite or a combination thereof may be employed. It seems that, citric acid may preferably be used to complete the present invention.

The buffering agent if used in the stable compositions of the present invention may be any pharmaceutically acceptable agent, known to a person skilled in the art. The buffering agent may be selected from a group consisting of organic acids and its salts, mineral acids, alkali metal phosphates, carbonates, borates, hydroxides, base and the like and mixtures thereof. Preferably selected from a group consisting of lactic acid, tartaric acid, phosphoric acid, acetic acid, hydrochloric acid, nitric acid, sodium or potassium metaphosphate, sodium or potassium phosphate, sodium or potassium acetate, ammonia, sodium carbonate, sodium or potassium hydroxide, dibasic sodium phosphate, sodium borate, and the like and mixtures thereof. The buffer components may also contribute substantially to osmotic pressure control.

Microbiological contamination presents a significant health hazard in liquid formulations. Therefore, the use of preservatives or disinfectants become inevitable to prevent the growth of microorganisms during the product’s manufacture and shelf life, although it may be most desirable to develop a “preservative-free” formulation to address the increasing concerns about the biological activity of these compounds. Most formulations require some kind of preservative to ensure no microbial growth. Non-limiting examples of preservatives when used in the formulations of the present invention include alcohol, ethanol, chlorobutanol, phenoxyethanol, potassium benzoate, benzyl alcohol, benzoic acid, potassium sorbate, sorbic acid, quaternary amine, benzethonium chloride, cetrimonium bromide, cetylpyridinium chloride, bronopol, chlorbutol, chlorocresol, cresol, parahydroxybenzoates, phenol, thymol, phenylethanol, sodium benzoate, antimicrobial solvents like propylene glycol, glycerin, chloroform and the like.

It is preferred for the quaternary amine preservative or disinfectant to be benzalkonium chloride, (NR1R2R3R4)+Cl-; where R1, R2=methyl, R3=benzyl, R4=C8H17 to C18H37. If present, the composition according to the invention contains the quaternary amine preservative or disinfectant preferably in a concentration from about 0.05 to about 0.2 mg per ml. Particularly, preferred is a concentration of about 0.1 mg per ml.

Chlorobutanol may also be the choice as preservative or disinfectant to be used in the compositions of the present invention. Chlorobutanol, if used in the present compositions, may be used in an amount ranging from 0.1 mg/mL to 5.0 mg/mL.

The parahydroxybenzoate preservative(s) if incorporated in the present compositions is/are selected from the group comprising methyl p-hydroxybenzoate (methyl paraben), ethyl p-hydroxybenzoate (ethyl paraben), propyl p-hydroxybenzoate (propyl paraben), butyl p-hydroxybenzoate (butyl paraben), isobutyl p-hydroxybenzoate (isobutyl paraben), isopropyl p-hydroxybenzoate (isopropyl paraben), benzyl p-hydroxybenzoate (benzyl paraben) and the like and mixtures thereof.

Typically, tonicity adjusting agents or osmotic pressure-controlling agents or osmolality agents are used to adjust the osmolality of the pharmaceutical compositions to bring it closer to the osmotic pressure of body fluids, such as blood or plasma. In some embodiments the tonicity of the formulation can be modified by adjusting the concentration of buffer and/or other components present in the formulation.

Provided that the compositions are physiologically compatible, the compositions do not require any particular osmolality. Thus, the compositions can be hypotonic, isotonic or hypertonic. Typically, the pharmaceutical compositions have a tonicity between about 250 to about 350 mOsm/kg. In some of the alternative embodiments, the formulations of the present invention are isotonic, i.e., in the range of 270-328 mOsm/kg. However, the formulations may have a tonicity in the range of 250-350 mOsm/kg. Therefore, the formulations may be either slightly hypotonic, 250-269 mOsm/kg, or slightly hypertonic, 329-350 mOsm/kg.

Suitable tonicity adjusting agents for use in the pharmaceutical compositions include, but are not limited to, anhydrous or hydrous forms of sodium chloride, dextrose, sucrose, xylitol, fructose, glycerol, sorbitol, mannitol, potassium chloride, mannose, calcium chloride, magnesium chloride and other inorganic salts. The quantity of the tonicity adjusting agent in the formulation can be expressed in mg/ml or in g/L. In typical embodiments, the tonicity adjusting agent(s) is present from about 1 mg/ml to about 90 mg/ml. Thus, the pharmaceutical compositions can comprise one or more tonicity adjusting agents at about 1-5 mg/ml, at about 5-10 mg/ml, at about 10-15 mg/ml, at about 15-25 mg/ml, at about 25-50 mg/ml, at about 50-60 mg/ml, at about 60-70 mg/ml, at about 70-80 mg/ml, and at about 80 to 90 mg/ml, as well as combinations of the above ranges.

Alternatively, the tonicity adjusting agent concentration is measured in weight/volume percent. In typical embodiments, the tonicity adjusting agent(s) is present from about 0.1% to about 10%. For example, suitable tonicity adjusting agent concentrations include, but are not limited to, from about 0.1% to about 0.2%, from about 0.2% to about 0.3%, from about 0.3% to about 0.4%, from about 0.4% to about 0.5%, from about 0.5% to about 0.6%, from about 0.6% to about 0.7%, from about 0.7% to about 0.8%, from about 0.8% to about 0.9%, from about 0.9% to about 1%, from about 1% to about 2%, from about 2% to about 3%, from about 3% to about 4%, from about 4% to about 5%, from about 5% to about 6%, from about 6% to about 7%, from about 7% to about 8%, from about 8% to about 9%, and from about 9% to about 10%, as well as combinations of the above ranges.

It is preferred for the osmotic pressure-controlling agent to be sodium chloride. Typically, the concentration of sodium chloride suitable for use in the pharmaceutical compositions is between about 0.1% (w/v) to about 1.8%. By way of example, suitable sodium chloride concentrations include, but are not limited to, from about 0.1% to about 0.2%, from about 0.2% to about 0.3%, from about 0.3% to about 0.4%, from about 0.4% to about 0.5%, from about 0.5% to about 0.6%, from about 0.6% to about 0.7%, from about 0.7% to about 0.8% (which is equivalent to 8 mg/ml), from out 0.8% to about 0.9% (which is equivalent to 9 mg/ml), from about 0.9% to about 1.0%, from about 1% to about 1.2%, from 1.2% (which is equivalent to 12 mg/ml) to about 1.4%, from about 1.4% to about 1.6%, and from about 1.6% to about 1.8%.

In some embodiments, the pharmaceutical compositions comprise two, three, four, or more tonicity adjusting agents. In these embodiments, the concentration of each tonicity adjusting agent is typically less than the concentration that is used when only a single agent is present in the formulation.

The pH adjusting agent(s) may also be required in the formulations of the present invention to adjust the desired pH of the formulation. Suitable pH adjusting agents typically include at least an acid or a salt thereof, and/or a base or a salt thereof. Acids and bases can be added on an as needed basis in order to achieve the desired pH. For example, if the pH is greater than the desired pH, an acid can be used to lower the pH to the desired pH. Acids suitable for use in formulations include, but are not limited to, hydrochloric acid, phosphoric acid, ascorbic acid, acetic acid, sulphuric acid, carbonic acid, nitric acid and the like. By way of another example, if the pH is less than the desired pH, a base can be used to adjust the pH to the desired pH. Bases suitable for use in formulations include, but are not limited to, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium acetate, magnesium hydroxide and the like.

A “buffering agent” or a “pH adjusting agent” as used herein is a system, which is used for the purposes and is capable of maintaining the desired/required pH of the formulations throughout desired/required time period, e.g. stability studies and/or shelf life of the drug product. The desired pH of the formulations according to the present invention is between about 3.5 and about 6.5.

In some of the embodiments of the invention, both buffering agent and pH adjusting agent may be used. In some of the embodiments of the invention, only a buffering agent is used. In some of the embodiments of the invention, only a pH adjusting agent is used.

In some of the preferred embodiments, hydrochloric acid and/or sodium hydroxide is used on an as needed basis as a pH adjusting agent(s) which adjusts and/or maintains the desired/required pH (e.g. about 3.5 to about 6.5).

An exemplary embodiment of the composition according to the present invention contains from about 0.001 mg to less than about 0.02 mg desmopressin or its salt, an antioxidant in a quantity sufficient to prevent and/or slow down the degradation of desmopressin or its salt, a preservative or disinfectant in a quantity sufficient to prevent the microbial contamination or microbial growth (the amount of the preservative depends on the preservative used), an osmotic pressure-controlling agent in a quantity sufficient to provide the overall solution with an osmotic pressure comparable to that of human plasma and a pH adjusting agent in a quantity sufficient to adjust/maintain the pH of the solution to about 3.5 to about 6.5. A buffering agent in a quantity sufficient to maintain the pH of the solution to about 3.5 to about 6.5 may optionally be included in the present composition. Also, one or more additives/excipients from chelating agents and cosolvents may optionally be included in the present composition.

An alternative embodiment of the composition according to the invention contains from about 0.001 mg to less than about 0.02 mg of desmopressin acetate, from about 1.35 to about 1.85 mg of citric acid, from about 0.05 to about 0.20 mg benzalkonium chloride or about 0.5 mg to about 5.0 mg chlorobutanol, and sodium chloride in an amount sufficient to provide the overall solution with an osmotic pressure comparable to that of human plasma. Hydrochloric acid and/or sodium hydroxide is used on an as needed basis as a pH adjusting agent(s) which adjusts and/or maintains the desired/required pH between about 3.5 and about 6.5. Optionally, a buffering agent in a quantity sufficient to maintain the pH of the solution to about 3.5 to about 6.5 may be included in the present composition.

More preferably, the composition of the present invention contains from about 0.004 to less than about 0.02 mg of desmopressin acetate, preferably about 0.004 mg, from about 1 to about 2.5 mg of citric acid monohydrate, preferably about 1.7 mg, 1 ml of water and an amount of sodium chloride such that the osmolality is kept at the physiological values of the human plasma. Hydrochloric acid and/or sodium hydroxide is used on an as needed basis as a pH adjusting agent(s) which adjusts and/or maintains the desired/required pH between about 3.5 and about 6.5.

However, in an alternative embodiment of the present invention, above mentioned compositions may optionally be prepared in the presence of a buffer. For example, from about 2 to about 5 mg of disodium hydrogen phosphate dihydrate, preferably about 3 mg may be included in the composition.

Thus, in a preferred embodiment, the present invention provides a composition comprising from about 0.001 mg to less than about 0.02 mg desmopressin or its salt and from about 1.0 mg to about 2.5 mg of citric acid. Said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month, preferably for at least three months and more preferably for at least six months when stored at room temperature.

In a more preferred embodiment, the present invention provides a composition comprising about 0.004 mg desmopressin or its salt and about 1.7 mg of citric acid. Said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month, preferably for at least three months and more preferably for at least six months when stored at room temperature.

In some embodiments, the present invention provides a composition comprising:
from about 0.001 mg to less than about 0.02 mg of desmopressin acetate;
from about 1.0 to about 2.5 mg of citric acid;
from about 0.5 mg to about 5.0 mg chlorobutanol;
from about 6.5 mg to about 9.0 mg sodium chloride;
water; and
a pH adjusting agent selected from hydrochloric acid, sodium hydroxide or combination thereof,
wherein the pH of the composition is between about 3.5 and about 6.5, and
wherein said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month, preferably for at least three months and more preferably for at least six months when stored at room temperature.

In some of the preferred embodiments, the present invention provides a composition comprising:
about 0.004 mg desmopressin acetate;
about 1.7 mg citric acid;
about 5.0 mg chlorobutanol;
about 7.5 mg sodium chloride;
water; and
a pH adjusting agent selected from hydrochloric acid, sodium hydroxide or combination thereof,
wherein the pH of the composition is between about 3.5 and about 6.5, and
wherein said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month, preferably at least three months and more preferably at least six months when stored at room temperature.

From the experimental studies, it was found out that the hydrated state of citric acid has no impact on its ability to prevent oxidation and prevent degradation of desmopressin or its salt. For example, both citric acid monohydrate and citric acid anhydrous effectively prevents oxidation & degradation of desmopressin or its salt. Thus, both hydrated citric acid and anhydrous citric acid are covered within the term “citric acid”.

In some of the alternative embodiments of the present invention, the compositions of the present invention may optionally comprise one or more additives selected from chelating agents and cosolvents.

Chelating agents if used in the compositions of the present invention may include, but are not limited to, ethylene diaminetetraacetic acid (EDTA), deferoxannine, desferrioxannine B, dithiocarb sodium, penicillamine, pentetate calcium, a sodium salt of pentetic acid, succimer, trientine, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, trans-diaminocyclohexanetetraacetic acid (DCTA), dihydroethylglycine, bis(anninoethyl)glycolether-N,N,N',N'-tetraacetic acid, iminodiacetic acid, poly(aspartic acid), tartaric acid, fumaric acid, succinic acid, glycolic acid, lactic acid, oxalic acid, malic acid, lecithin or any salt thereof, and the like or a combination thereof may be employed.

Cosolvents if used in the formulations of the present invention without limitation include dichloromethane, acetonitrile, ethyl acetate, acetone, propylene carbonate, water, glycerin, coconut fatty acid diethanolamide, medium and/or long chain fatty acids or glycerides, monoglycerides, diglycerides, triglycerides, structured triglycerides, soyabean oil, peanut oil, corn oil, corn oil monoglycerides, corn oil diglycerides, corn oil triglycerides, polyethylene glycol, caprylocaproylmacroglycerides, caproyl 90, propylene glycol, polyoxyethylenesorbitan fatty acid esters, polyoxyethylene castor oil derivatives, castor oil, cottonseed oil, olive oil, safflower oil, peppermint oil, coconut oil, palm seed oil, beeswax, oleic acid, methanol, ethanol, isopropyl alcohol, butanol, acetone, methyl isobutyl ketone, methyl ethyl ketone and any combination thereof.

So far, aqueous compositions of the present invention are concerned, in some embodiments, the compositions are ready-to-use aqueous compositions. In alternative embodiments, the compositions are ready-to-dilute aqueous compositions.

The desmopressin compositions of the present invention may be indicated and used for the therapeutic indications those identified & provided for DDAVP Injection under the heading “Indications and usage” in the patient information leaflet (https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/018938s035lbl.pdf).

In some embodiments, the composition of the present invention is for intravenous or subcutaneous administration. In some embodiments, the present invention provides use of the composition as disclosed herein for the management of diseases and abnormal conditions, which are mitigated by administration of desmopressin or its salt.

Definitions
As used herein, the term “stable or stabilized composition” refers to an aqueous solution for therapeutic use, containing at least one small or medium-size biologically active peptide, particularly desmopressin or its salt. Such stabilization should allow the composition to be stored at room temperature for extended periods without loss in biological activity.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

As used herein, the term “about” is synonymous with “approximately” and is used to provide flexibility to a numerical value or range endpoint by providing that a given value may be “a little above” or “a little below” the value stated. “About” can mean, for example, within 3 or more than 3 standard deviations. “About” can mean within a percentage range of a given value. For example, the range can be ±1 %, ±5%, ±10%, ±20%, ±30%, ±40% or ±50% of a given value. “About” can mean with an order of magnitude of a given value, for example, within 2-fold, 3-fold, 4-fold or 5-fold of a value. However, it is to be understood that even when a numerical value is accompanied by the term “about” in this specification, that express support shall be provided at least for the exact numerical value as well as though the term “about” were not present.

As used herein, “optional” or “optionally” means that the subsequently described event or circumstance does or does not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. For example, an optionally substituted group means that the group is un-substituted or is substituted.

The term “room temperature” as used herein includes storage conditions 25°C±5°C and 60% ±5% relative humidity.

The term “degradant”, “impurity”, “degradation impurity” and “related substance” as used herein represents the same meaning and can be used interchangeably.

In some embodiments, the compositions of the present invention are stable for prolonged time when stored under storage conditions. The term “storage conditions” as used herein without limitation include storage conditions such as 25°C. The compositions of the present invention may also be stored at 40°C±2°C/75±5% RH, 30°C±2°C/65±5% RH, 25°C±2°C/40±5% RH, 25°C±2°C/60±5% RH, 40°C±2°C/NMT 25% RH (NMT = not more than) and accelerated conditions such as 40°C±2°C/75±5% RH. The term “prolonged time” as used herein indicates that the formulations of the present invention are stable for at least 1 month or more, at least 3 months or more, at least 6 months or more or at least 12 months or more when stored under storage conditions.

As used herein, “comprises”, “comprising”, “containing” and “having” and the like can have the meaning ascribed to them in patent law and can mean “includes”, “including” and the like, and are generally interpreted to be open ended terms. The terms “consisting of” or “consists of” are closed terms, and include only the components, structures, steps, or the like specifically listed in conjunction with such terms, as well as that, which is in accordance with patent law. “Consisting essentially of” or “consists essentially of” have the meaning generally ascribed to them by patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the composition’s nature or characteristics would be permissible if present under the “consisting essentially of” language, even though not expressly recited in a list of items following such terminology. When using an open ended term, like “comprising” or “including” it is understood that direct support should be afforded also to “consisting essentially of” language as well as “consisting of” language as if stated explicitly and vice versa. In essence, use of one of these terms in the specification provides support for all of the others. The term “comprise/comprises/comprising” as used herein mean that other ingredients, steps, etc. are optionally present. When reference is made herein to a method comprising two or more defined steps, the steps can be carried in any order or simultaneously (except where the context excludes that possibility), and the method can include one or more steps which are carried out before any of the defined steps, between two of the defined steps, or after all of the defined steps (except where the context excludes that possibility).

Ready-to-use compositions according to the present invention are meant to be administered directly to the patients in required doses without any prior preparation e.g. reconstitution or dilution with suitable diluent such as saline solution or water. Ready-to-dilute or concentrated compositions according to the present invention requires dilution to desired concentration using suitable diluent such as saline solution or water before administration to the patients.

Methods for determining the stability of the compositions of the present invention with respect to a given parameter are well-known to those of skill in the art. For example, individual impurities and total impurities can be assessed by high-performance liquid chromatography (HPLC) or thin layer chromatography (TLC). Unless otherwise indicated to the contrary, a percentage amount of any individual impurities (known/unknown), or total impurities reported herein in the formulations are determined by a peak area percent method using HPLC.

As used herein, “treatment” refers to ameliorating or reducing symptoms associated with a disease or condition. Treatment means any manner in which the symptoms of a condition, disorder or disease are ameliorated or otherwise beneficially altered. Hence treatment encompasses prophylaxis, therapy and/or cure. Treatment also encompasses any pharmaceutical use of the compositions herein.

As used herein, “treating” a subject having a disease or condition means that a composition or other product provided or described herein is administered to the subject to thereby effect treatment thereof.

As used herein, amelioration of the symptoms of a particular disease or disorder by a treatment, such as by administration of a pharmaceutical composition or other therapeutic, refers to any lessening, whether permanent or temporary, lasting or transient, of the symptoms that can be attributed to or associated with administration of the composition or therapeutic.

As used herein, “prevention” or “prophylaxis” refers to methods in which the risk of developing disease or condition is reduced. Prophylaxis includes reduction in the risk of developing a disease or condition and/or a prevention of worsening of symptoms or progression of a disease, or reduction in the risk of worsening of symptoms or progression of a disease.

As used herein an “effective amount” of a compound or composition for treating a particular disease is an amount that is sufficient to ameliorate, or in some manner reduce symptoms to achieve the desired physiological effect. Such amount can be administered as a single dosage or can be administered according to a regimen, whereby it is effective. The effective amount is readily determined by one of skill in the art following routine procedures.

As used herein, “disease” or “disorder” or “condition” refers to a pathological condition in an organism resulting from cause or condition including, but not limited to, infections, acquired conditions, genetic conditions, and characterized by identifiable symptoms.

As used herein, “patient” or “subject” to be treated includes humans and or non-human animals, including mammals. Mammals include primates, such as humans, chimpanzees, gorillas and monkeys; domesticated animals, such as dogs, horses, cats, pigs, goats, cows; and rodents such as mice, rats, hamsters and gerbils.

In some embodiments, the present invention also provides a container comprising a composition comprising desmopressin or its salt. In certain embodiments, the container is a vial, an ampoule, a bag, a bottle, a cartridge, or a syringe. In some embodiments, the container, the composition, or both the container and the composition are sterile. Preferably, the container is sealed by way of a closure, such as a stopper, plunger, and/or tip-cap.

The container and closure can be made of glass, plastic, and/or rubber. One or more surfaces of the container and/or closure can be treated with a compound to limit reactivity with one or more components of the formulation. In some embodiments, the container and/or closure are treated with silicon. In other embodiments, the container is treated with ammonium sulfate ((NH4)2SO4). The container can be clear or opaque, and can be any color. In some embodiments, the container is flint colored. In other embodiments, the container is amber colored.

In some embodiments, the invention provides a pre-filled syringe containing a composition of the invention described herein. In some embodiments, a syringe according to the invention is a component of an auto-injector.

All percentages mentioned herein, unless otherwise indicated, are on a w/v basis, i.e. percentage ingredient (active/inactive) present by weight in the total volume of the composition.

BEST MODE OF CARRYING OUT THE INVENTION
EXAMPLE(S)
The invention will now be explained in more detail by way of the following non-limiting examples.

Example-1: Preparation of desmopressin aqueous solutions with and without antioxidant
Batch No. DESP1017
(without antioxidant) DESP1018
(with antioxidant) Role of ingredient
Desmopressin acetate (0.0036 mg desmopressin) 0.004 mg/mL (4 mcg/mL) 0.004 mg/mL (4 mcg/mL) Active principle
Citric acid monohydrate - 1.70 mg/mL Antioxidant
Sodium chloride 9.0 mg/mL 7.5 mg/mL Osmotic pressure-controlling agent
Chlorobutanol* 5.0 mg/mL 5.0 mg/mL Preservative/Disinfectant
Hydrochloric acid and/or Sodium hydroxide In a quantity sufficient to adjust pH between about 4.0 and about 6.5 In a quantity sufficient to adjust pH between about 4.0 and about 6.5 pH adjusting agent
Water In a quantity sufficient to 1.0 mL In a quantity sufficient to 1.0 mL Vehicle
Other suitable preservatives/disinfectants may also be used in place of chlorobutanol in a quantity sufficient to prevent microbial growth in the formulation.

Required quantities of citric acid monohydrate and sodium chloride were dissolved in the sufficient amount of water to achieve the concentration of citric acid and sodium chloride 1.7 mg/mL & 7.5 mg/mL respectively. Required quantities of chlorobutanol and desmopressin acetate were dissolved in the above solution to achieve the concentration of chlorobutanol and desmopressin acetate 5 mg/mL & 0.004 mg/mL respectively. Required quantities of water was added to make up the final volume to the batch size (bulk solution).

Table-1: Stability study results of batch nos. DESP1017 & DESP1018
Batch No. DESP1017 DESP1018
Test Parameters Initial 30°C/65±5% RH
3 months 25°C/60±5% RH
3 months 2-8°C
3 months Initial 30°C/65±5% RH
3 months 25°C/60±5% RH
3 months 2-8°C
3 months
% Assay of desmopressin 109.6 104.0 106.7 107.9 114.7 112.7 113.3 113.9
% Assay of chlorobutanol 102.4 103.0 102.7 103.4 103.9 92.1 95.6 100.6
pH 4.65 3.63 3.99 4.25 4.65 4.75 4.81 4.88
Osmolality 319 321 322 320 289 284 285 288
Related substances (% w/w)
9-Glycine ND 1.07 0.35 0.03 ND 0.14 0.08 0.02
5-L-Aspartic acid ND 0.54 0.27 0.18 ND ND ND ND
4-L-Glutamic acid ND 1.35 0.43 0.06 ND 0.16 0.09 0.05
8-L-Arginine 0.08 0.09 0.10 0.09 0.09 0.09 0.06 0.09
RRT 0.62/0.68 (Oxidation) 0.08 0.21 0.35 0.35 ND ND ND ND
Single maximum
unspecified impurity 0.08 0.21 0.35 0.35 0.05 0.08 0.07 0.06
Total impurities 0.28 3.96 1.92 0.95 0.14 0.56 0.36 0.19
ND = not detected, RH = relative humidity

From above, it can be seen that, at all stability time points the amounts of the total impurities in the desmopressin aqueous solution containing an antioxidant was much lower as compared to the desmopressin aqueous solution not containing an antioxidant. Particularly, at room temperature (25°C) after three months, the amounts of total impurities were 0.36% w/w in the desmopressin aqueous solution containing an antioxidant as compared to the desmopressin aqueous solution not containing an antioxidant, which had 1.92% w/w amounts of the total impurities at room temperature (25°C) after three months.

Example-2: Selection of an antioxidant
Different batches were prepared using different antioxidants to study the effect of different antioxidants on the stability of the desmopressin compositions. The formulation composition details are summarized below and the stability study results of these batches with different antioxidants are summarized in Table-2.
Batch No. DESP1027B
(with citric acid) DESP1019
(with L-cysteine HCl) Role of ingredient
Desmopressin acetate (0.0036 mg desmopressin) 0.004 mg/mL (4 mcg/mL) 0.004 mg/mL (4 mcg/mL) Active principle
Citric acid anhydrous 1.70 mg/mL - Antioxidant
L-cysteine Hydrochloride - 1.0 mg/mL Antioxidant
Sodium chloride 7.5 mg/mL 9.0 mg/mL Osmotic pressure-controlling agent
Chlorobutanol* 5.0 mg/mL 5.0 mg/mL Preservative/Disinfectant
Hydrochloric acid and/or Sodium hydroxide In a quantity sufficient to adjust pH between about 4.0 and about 6.5 In a quantity sufficient to adjust pH between about 4.0 and about 6.5 pH adjusting agent
Water In a quantity sufficient to 1.0 mL In a quantity sufficient to 1.0 mL Vehicle
Other suitable preservatives/disinfectants may also be used in place of chlorobutanol in a quantity sufficient to prevent microbial growth in the formulation.

The batch preparation was started with sufficient quantity of water. Nitrogen was purged in the water to obtain dissolved oxygen level below 2 ppm (parts per million) and it was maintained until the end of the batch manufacturing. Required quantities of an antioxidant selected from citric acid anhydrous or L-cysteine hydrochloride and sodium chloride were added and dissolved under stirring. pH of the above solution was adjusted between about 4.0 and about 6.5 (preferably to about 4.0) using 1N sodium hydroxide solution and/or 0.1 N hydrochloric acid solution (as the requirement may be). Required quantity of chlorobutanol (preferably anhydrous) was added and stirred until complete solubilization. Above solution was cooled down to refrigerated temperature (2-8°C). Required quantity of desmopressin acetate (API) was added to above cooled solution and stirred until complete solubilization of the API. Remaining quantity of water was added to make up the final volume to the desired batch size (bulk solution). Bulk solution was filtered using 0.22 µm PVDF filter and filled into 5 mL USP type-I clear glass vials with headspace oxygen (HSO) below 5% v/v.

Table-2: Stability study results of batch nos. DESP1017 & DESP1018
Batch No. DESP1019 DESP1027B
Antioxidant L-cysteine HCl Citric acid anhydrous
Storage condition Initial Initial 2-8°C 25°C/60% RH
Stability time point 3 months 6 months 3 months 6 months
Test Parameters
% Assay of desmopressin 91.6 103.0 103.6 104.2 103.4 103.8
% Assay of chlorobutanol 92.5 104.9 104.7 104.7 104.4 103.7
Content of citric acid - 101.3 - 99.1 - 99.1
pH 4.162 4.903 5.032 4.921 4.999 4.864
Osmolality 338 292 293 288 293 291
Headspace oxygen Not performed 3.01 2.88 2.91 3.15 3.25
Related substances (% w/w)
(5-L-Aspartic acid) Desmopressin ND 0.14 0.12% 0.09% 0.13% 0.12%
(4-L-Glutamic acid) Desmopressin ND ND ND ND 0.08% 0.13%
(9-Glycine) Desmopressin ND ND ND ND 0.04% 0.09%
(8-L-Arginine) Desmopressin 0.07 0.07 0.05% 0.13% 0.06% 0.11%
Any individual unspecified impurity 1.56 0.05 0.06% 0.10% 0.05% 0.10%
Total impurities 2.73 0.35 0.26% 0.36% 0.36% 0.61%
ND = not detected, RH = relative humidity

Above results show that the assay value of desmopressin acetate of the test product with L-cysteine hydrochloride as an antioxidant (DESP1019) was outside the acceptable limit at initial time point. Further, an individual unspecified impurity in the test product with L-cysteine hydrochloride as an antioxidant (DESP1019) was also higher than the acceptable limit at initial time point only. Whereas, the test product with citric acid as an antioxidant showed all test parameters well within the acceptable limits at both storage conditions and at all time points. Thus, in view of the above results citric acid was selected as a preferred antioxidant for further development.

Example-3: Optimization of concentration of an antioxidant
Four batches, DESP1027B, DESP1031, DESP1032 and DESP1034 were prepared by using different amounts of citric acid, i.e. 1.70mg/mL (100% of the label claim), 1.28mg/mL (75% of the label claim), 0.85mg/mL (50% of the label claim) and 3.40mg/mL (200% of the label claim) respectively to optimize the concentration of citric acid. These batches were stored under refrigerated conditions (2-8°C) and at room temperature (25°C) and tested at 0 (initial), 3 and 6 months’ time points. The results (not included here) show that DESP1027B & DESP1031 showed all test parameters (e.g. percentage assay of desmopressin & chlorobutanol, concentration of citric acid, pH, osmolality, HSO, and related substances etc.) well within the acceptable limits. Whereas, the %w/w amount of impurity (4-L-Glutamic acid) desmopressin in DESP1032 was at the borderline of the acceptable limit after 6 months at 25°C and the %w/w amount of impurity (4-L-Glutamic acid) desmopressin in DESP1034 was higher than the acceptable limit after 6 months at 25°C. Based on these results, the concentration of citric acid to be used in the formulation was finalized to be 1.70mg/mL.

It has been documented in the prior arts that diluted aqueous peptide solutions in general are not stable at room temperature for longer periods, even if kept in sealed containers. Desmospressin or its salt is such a peptide. Its aqueous solution has to be stored at a temperature not exceeding 8°C. Storage at higher temperatures such as, for instance, room temperature, results in the degradation of desmopressin by hydrolytic and/or oxidative processes, which are not blocked by the addition of a preservative, such as chlorobutanol although chlorobutanol effectively protects desmopressin against microbial attack. Where, room temperature desmopressin compositions are prepared, they contain very higher amount of desmopressin such as 0.1 mg/mL. Thus, room temperature stable diluted aqueous solution comprising 0.004 mg/mL desmopressin or its salt neither are taught nor are suggested. Further, it was also not taught in the prior art that such diluted solutions can be stabilized at room temperature with the help of antioxidant such as citric acid. The inventors of the present invention through their research have proved that the room temperature stable diluted aqueous solution of desmopressin can be prepared with the help of antioxidant such as citric acid.

Therefore, it can be concluded that with the help of an antioxidant (such as citric acid), a room temperature stable desmopressin aqueous solution may be prepared which may have shelf life of at least 12 months or more.

The compositions of the present invention as described herein are suitable for use in the industry.

It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the subject matter of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered within the scope of the present invention. ,CLAIMS:WE CLAIM,
1. A composition comprising from about 0.001 mg to less than about 0.02 mg desmopressin or its salt and from about 1.0 mg to about 2.5 mg citric acid wherein said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month when stored at room temperature.
2. The composition as claimed in claim 1, wherein the total impurities remain at less than 1% w/w for at least three months when stored at room temperature.
3. The composition as claimed in claim 1, wherein the total impurities remain at less than 1% w/w for at least six months when stored at room temperature.
4. A composition comprising about 0.004 mg desmopressin or its salt and about 1.7 mg citric acid wherein said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month when stored at room temperature.
5. The composition as claimed in claim 1 and claim 4, wherein said composition further comprises about 0.5 mg to about 5.0 mg chlorobutanol, from about 6.5 mg to about 9.0 mg sodium chloride, water, and a pH adjusting agent selected from hydrochloric acid, sodium hydroxide or combination thereof to adjust the pH of the composition between about 3.5 and about 6.5.
6. The composition as claimed in claim 1 or claim 4, wherein the total impurities remain at less than 0.5% w/w for at least one month when stored at room temperature.
7. A composition comprising:
about 0.004 mg desmopressin acetate;
about 1.7 mg citric acid;
about 5.0 mg chlorobutanol;
about 7.5 mg sodium chloride;
water; and
a pH adjusting agent selected from hydrochloric acid, sodium hydroxide or combination thereof,
wherein the pH of the composition is between about 3.5 and about 6.5; and wherein said composition is stable at room temperature wherein the total impurities remain at less than 1% w/w for at least one month when stored at room temperature.
8. The composition as claimed in claim 7, wherein the total impurities remain at less than 0.5% w/w for at least one month when stored at room temperature.
9. The process of preparing a composition as claimed in claim 7, wherein the process comprises:
citric acid and sodium chloride are dissolved in the required amounts in water having dissolved oxygen level below 2 parts per million (ppm) achieved through nitrogen purging;
the pH of the above solution is adjusted to between about 3.5 and about 6.5 using a pH adjusting agent selected from hydrochloric acid, sodium hydroxide or combination thereof;
required amount of chlorobutanol was dissolved in the above solution and the solution was cooled down to 2-8°C;
desmopressin acetate in the required amount was dissolved in the above-mentioned cooled solution followed by addition of the required amount of remaining water to make up the volume to the desired batch size; and
above solution was filtered and filled into suitable vials having head space oxygen below 5% v/v.
10. The use of the composition as claimed in any one of the preceding claim, wherein the composition is for intravenous or subcutaneous administration for the management of diseases and abnormal conditions, which are mitigated by administration of desmopressin or its salt.

Dated this 10th day of November, 2023

Dhaval Joshipura [IN/PA-2605]
IPM Department
For and on behalf of FTF Pharma Private Limited