DESC:FIELD OF THE INVENTION

The present invention relates to a stable injectable formulation comprising a biologically active lipopeptide i.e. Daptomycin, excipients/stabilizers and pH-adjusting agent, for reconstitution in a liquid diluent to form a pharmaceutical formulation for parenteral administration. The present invention relates to processes for preparation of such stable solid lipopeptide formulation of Daptomycin with good rates of reconstitution and improved Daptomycin chemical stability. The invention further relates to the reconstitution of lyophilized Daptomycin formulation for intravenous administration and the use of such formulations in the treatment of complicated skin and skin structure infections and bacteremia with suspected or proven infective endocarditis.

BACKGROUND OF THE INVENTION
Daptomycin, is a cyclic lipopeptide antibacterial agent with a broad spectrum of activity against gram-positive organisms, both aerobic and anaerobic. Daptomycin is derived as a fermentation product from Streptomyces roseosporus. The chemical name is N-decanoyl-Ltryptophyl-D-asparaginyl-L-aspartyl-L-threonylglycyl-L-ornithyl-L-aspartyl-D-alanyl-L-aspartylglycyl-Dseryl-threo-3-methyl-L-glutamyl-3-anthraniloyl-L-alanine ?1-lactone. Daptomycin is structurally represented as:

Daptomycin is a lipopeptide antibiotic used in the treatment of complicated skin and skin structure infections (cSSSI) caused by Gram-positive organisms. Daptomycin has also been used for treating Staphylococcus aureus bloodstream infections (bacteremia), including those with right-sided infective endocarditis, caused by methicillin-susceptible and methicillin-resistant isolates. It is a naturally occurring compound found in the soil saprotroph Streptomyces roseosporus.

Daptomycin consists of 13 amino acids, 10 of which are arranged in a cyclic fashion, and three on an exocyclic tail. In Daptomycin two nonproteinogenic amino acids exist, which include the unusual amino acid L-kynurenine (Kyn) only known to Daptomycin and L-3-methylglutamic acid (mGlu). Further it is known to be characterized with, the N-terminus of the exocyclic tryptophan residue which is coupled to decanoic acid. Daptomycin undergoes degradation and the major known degradants/ impurities are anhydro-Daptomycin, ß-isomer of Daptomycin and the lactone hydrolysis product.

Currently Daptomycin (500mg/vial) is marketed under brand name “CUBICIN® RF” & “CUBICIN” in the United States by Cubist Pharmaceuticals Inc and is supplied as a sterile, lyophilized powder for injection which is reconstituted with a pharmaceutical diluent prior to the intravenous administration. Further, Daptomycin (350mg/vial) is marketed by Sagent & Xellia Pharmaceuticals. During the preparation of Cubicin for administration, it is essential that the contents of the vial should be reconstituted using aseptic technique which is described as follows: i) Avoiding vigorous agitation or shaking of the vial during or after reconstitution to minimize foaming; ii) Removing the polypropylene flip-off cap from the vial to expose the central portion of the rubber stopper; iii) Slowly transferring 10 mL of 0.9% sodium chloride injection through the center of the rubber stopper into the vial, pointing the transfer needle towards the wall of the vial; iv) Ensuring that the entire product is wetted by gently rotating the vial; v) Allowing the product to stand undisturbed for 10 minutes; and vi) Gently rotating or swirling the vial contents for a few minutes, as needed, to obtain a completely reconstituted solution. In general the lyophilized Daptomycin powder can take about 15 to 45 minutes for reconstitution, depending on the reconstitution procedure which is rather long. Stability studies have shown that at higher temperatures, Daptomycin begins to degrade and further it is known that the reconstituted form is stable for short period at room temperature. Considering the rates of reconstitution and chemical stability of Daptomycin, there is a need for development of pharmaceutical formulations of Daptomycin which have faster reconstitution time with improved chemical stability at different storage conditions. Thus the goal of the present invention is to formulate a chemically stable Daptomycin in solid as well as the reconstituted form with good rates of reconstitution, wherein the improved properties of stability provides a safe medication with enhanced clinical efficacy.

Several attempts have been made in the prior art to provide optimal and stable injection formulations of Daptomycin. U.S. Patent No. 9,138,456 discloses a solid pharmaceutical Daptomycin formulation, wherein said formulation is prepared by lyophilizing an aqueous Daptomycin solution comprising Daptomycin and sucrose. U.S. Patent No. 9,655,946 discloses a lyophilized Daptomycin formulation comprising an additive selected from the group consisting of pharmaceutically acceptable organic acids and salts thereof, acetyl glucosamine, and combinations thereof, wherein the formulations have improved reconstitution time. U.S. Publication No. 20170348382 discloses a lyophilized injectable formulation comprising Daptomycin or pharmaceutically acceptable salts or solvates thereof and a preservative, wherein said formulation has an improved reconstitution time. U.S. Publication No. 20150216928 discloses a stable, lyophilized formulation comprising Daptomycin and tocopheryl phosphate hydrolysate mixture (TPM), wherein said lyophilized formulation is directly reconstitutable within 5 minutes for parenteral administration. U.S. Patent No. 8,431,539 discloses a long term storage stable Daptomycin-containing formulation comprising: Daptomycin or a pharmaceutically acceptable salt thereof at a concentration of less than or equal to about 25 mg/mL; b) buffer having an acidic functional group, c) calcium hydroxide. The aforementioned prior arts discloses the formulations of Daptomycin that are stable for a less period at different conditions or undergo premature degradation upon reconstitution or require refrigeration for maintenance or have poor long-term chemical stability or not commercially viable. The currently marketed Daptomycin formulation (CUBICIN® RF), which was a reformulation with sucrose exhibited improved reconstitution time and stability. However, it is known in the art that sucrose affects the stability of peptides in the long term. Hence, there still exists a need for alternative lyophilized Daptomycin formulations that exhibit good reconstitution times, improved chemical stability, that are commercially viable and easy to manufacture, using excipients other than sucrose. Therefore, the inventors of the present invention have developed pharmaceutical formulations of Daptomycin using alternative excipients. These alternate excipients used in the present invention stabilizes the formulation, provides good reconstitution times and alleviates the limitations in the art by providing safe and commercially viable Daptomycin injectable preparations with less degradation.

SUMMARY OF INVENTION
The present invention relates to solid Daptomycin formulations for reconstitution with diluent to form pharmaceutical formulations. Aspects of the present invention relates to stable pharmaceutical formulations comprising therapeutically effective amount of Daptomycin or pharmaceutically acceptable salts or solvates thereof and at least one excipient selected from the group consisting of Mannitol, Dextran 40, Sorbitol, Hydroxypropyl Betadex, Betadex Sulfobutyl Ether Sodium, Glycine, L-Histidine, Arginine, Polyethylene glycol 3350 and Polyvinylpyrrolidone or their salts, or a combination thereof. The formulation further comprises a pH-adjusting agent, optionally a preservative and water for injection.

In an aspect of the present invention, the excipients other than sucrose stabilizes and provides good reconstitution time of the Daptomycin formulation, wherein the preferred excipients/stabilizers include Mannitol, Dextran 40, Sorbitol, Hydroxypropyl Betadex, Betadex Sulfobutyl Ether Sodium, Glycine, L-Histidine, Arginine, Polyethylene glycol 3350 and Polyvinylpyrrolidone or their salts, or a combination thereof and mixtures thereof.

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

Aspects of the present invention relates to a multi-step process which is tightly controlled by in-process controls for preparing the said Daptomycin formulations that exhibit faster reconstitution, good stability at different conditions. The solid Daptomycin preparation can be obtained by the following process: (a) forming an aqueous solution of the said excipient with Daptomycin (b) adjusting the pH of the liquid Daptomycin formulation to about 6.6 to 7.2; and (d) converting the Daptomycin formulation to the solid formulation (e.g., lyophilization).

Aspects of the present invention relates to stable pharmaceutical composition comprising: a) providing a lyophilized Daptomycin formulation with improved shelf life, b) reconstituting the said lyophilized formulation with a pharmaceutically acceptable diluent, wherein the said lyophilized formulation can be reconstituted in less than about 1.5 minutes; and c) administering a stable reconstituted Daptomycin to the human by intravenous administration.

Aspects of the present invention relate to, a method of treating infections caused by Gram-positive organisms by a) providing a pharmaceutical formulation comprising: Daptomycin or pharmaceutically acceptable salts or solvates thereof, pH-adjusting agent, suitable excipient/stabilizer and water for injection, b) storing the pharmaceutical formulation at different conditions and time periods; c) administering the pharmaceutical formulation that exhibits faster rates of reconstitution and with improved stability in the solid as well as reconstituted form after storage. The present invention further relates to methods of treatment using the said pharmaceutical formulations of the invention by administering an amount effective to combat the disease, condition, or disorder for which administration of Daptomycin in the formulation is indicated.

Aspects of the present invention relates to a stable reconstituted formulation of a lyophilized Daptomycin formulation, wherein the Daptomycin formulation exhibits less “known impurities” of Daptomycin after exposure to accelerated storage conditions for about 6 months when compared to reference product (Cubicin RF) that is exposed to accelerated storage conditions. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

DETAILED DESCRIPTION OF THE INVENTION
Within the scope of the description of the invention, Daptomycin and any of its addition salts are referred to as "Daptomycin". Also, unless otherwise stated, the terms "active ingredient" and "active substance" refer to Daptomycin and any of its pharmaceutically acceptable salts. The effective therapeutic amount of the active principle is advantageously such that the unit content of Daptomycin and it pharmaceutically acceptable salts is from about 250 mg/vial to about 500 mg/vial, preferably 500 mg/vial.

In embodiments, the pharmaceutical formulation provided herein comprises excipients/stabilizers to improve stability and reconstitution time of Daptomycin formulation. Certain non-limiting examples of stabilizers/excipients include Mannitol, Dextran 40, Sorbitol, HydroxypropylBetadex, BetadexSulfobutyl Ether Sodium, Glycine, L-Histidine, L-Arginine, Arginine, Polyethylene glycol 3350, Polyvinyl pyrrolidone, trehalose, glycine, mannitol, lactose, maltose, fructose, dextrose, or their salts, and combinations thereof. Preferred solid Daptomycin preparations having good reconstitution time and improved stability in powder and reconstituted forms are made by combining Daptomycin with excipients/stabilizers selected from HydroxypropylBetadex, BetadexSulfobutyl Ether Sodium, Polyethylene glycol 3350 & Polyvinylpyrrolidone, Arginine Hydrochloride and combinations thereof. In embodiments, the pharmaceutical formulation provided herein comprises excipients/stabilizers in the range of about 5 to 800 mg/vial. The said Daptomycin preparations demonstrated good chemical stability and were reconstituted in less than 2 minutes and with most formulations reconstituting in less than 1.5 minutes. In certain embodiments of the present invention, the stable lyophilized formulation of present invention can be administered parenterally such as, intravenously, intramuscularly, intraperitonealy, subcutaneously, or via an implantable pump.

In embodiments, the stabilized formulation of the present invention has a pH-adjusting agent and the pH of the Daptomycin formulation is from about 5 to 8.0. Suitable pH-adjusting agent that can be used in the stabilized formulation of the present invention is selected from but not limited to a group comprising hydrochloric acid, sodium hydroxide, acetic acid, phosphoric acid, Lactic acid, Citric acid and mixtures thereof. More preferably sodium hydroxide is used to adjust the pH of the formulation.

In embodiments, the stabilized lyophilized formulation is reconstituted with the suitable diluent. Wherein the pharmaceutically acceptable diluent include sterile water for injection, bacteriostatic water for injection, sterile sodium chloride for injection, and Ringer's solution thereof. Additional examples of suitable diluent can be found in Remington's Pharmaceutical Sciences, 17th Ed., A. R Gennaro, Ed., Mack Publishing Co., Easton, Pa. 1985. More preferably sterile water for injection, bacteriostatic water or sterile sodium chloride injection is used. Preferably, one reconstitution method includes quickly adding a diluent to a vessel containing the said lyophilized Daptomycin formulations wherein the diluent can be added over a period of 1-60 seconds, followed by swirling of the vessel. Pharmaceutical formulations of the present invention can be reconstituted in any suitable volume wherein, the weight of Daptomycin in the formulation to the volume of the diluent is in the range of 25 mg/mL to 200 mg/mL.

In embodiments, a buffering agent is optionally added to the Daptomycin solutions wherein the buffering agents can include, for example, agents including phosphate, citrate, maleate, or carbonate moieties, or combinations thereof, and pharmaceutically appropriate counter ions. The amount of the buffering agent can be selected based on the molar ratio of the buffering agent to the Daptomycin. The buffering agent can be added in anhydrous or aqueous form. Specific examples of buffering agents are a sodium or potassium salt of phosphoric acid, a sodium or potassium salt of boric acid, a sodium or potassium salt of citric acid, a sodium or potassium salt of carbonic acid, sodium phosphate (e.g., Sodium phosphate dibasic), TRIS (tris(hydroxymethyl)aminomethane and salt of maleic acid. In one aspect the buffering agent is selected from sodium phosphate dibasic (Na2HPO4), sodium citrate, sodium bicarbonate, histidine monohydrochloride TRIS and maleate.

In embodiments, optionally preservative can be added to the stabilized formulation in order to inhibit the growth of microbial contaminants and suppress biodegradation. Suitable preservative is selected from but not limited to a group comprising phenol, m-cresol, methylparaben, phenoxyethanol, propylparaben, thimerosal, benzalkoniumchloride, benzethonium chloride, chlorhexidine gluconate, phenylmercuric acetate, phenylmercuric nitrate, phenylmercuric salts, chlorobutanol, methylhydroxybenzoate, chlorocresol, benzyl alcohol, sodium dehydroacetate, p-hydroxybenzoate, and the like, and mixtures thereof.

In embodiments, lyophilization or freeze drying or spray drying or the like is done. Lyophilization is a process in which a drug substance is first frozen (freezing) and then the quantity of the solvent is reduced, by sublimation (primary drying process) and then desorption (secondary drying process). In the embodiments of the present invention the lyophilization process comprises one or more annealing steps during freezing. The annealing step is done at a temperature range between -5° C. and -30° C. during the freezing.

In embodiments, the expression of "stable formulation" is intended to mean shelf stable formulation, formulation with increased tolerance for more varied storage conditions (e.g., higher temperature or humidity), formulation stable during different temperatures for a longer period of time, formulation stable prior to first use and stable after reconstitution as a liquid formulation for parenteral administration. As used herein, the term "Stabilized formulation” further refers to a stable formulation for therapeutic use, containing Daptomycin with less degradation products. The major Daptomycin degradation products are anhydro-Daptomycin derivatives in which an a-aspartyl group is transpeptidated to an anhydrosuccinamido group, ß-isomer of Daptomycin in which the compound contains a ß-aspartyl group instead of an a-aspartyl group and the lactone hydrolysis product in which one of the esters moieties is hydrolyzed.

In one of the emboidments, measure of the chemical stability of Daptomycin in the lyophilized Daptomycin powder is the amount of Daptomycin present in the reconstituted Daptomycin composition relative to the amount of structurally similar compounds including anhydro-Daptomycin, beta-isomer of Daptomycin and a lactone hydrolysis product of Daptomycin. The amount of Daptomycin relative to the amount of these structurally similar compounds can be measured by high performance liquid chromatography (HPLC) after reconstitution in an aqueous diluent. The purity of Daptomycin and amounts of structurally similar compounds can be determined from peak areas obtained from HPLC to provide a measure of Daptomycin chemical stability in a solid form. The Daptomycin purity and chemical stability can also be measured within the liquid reconstituted Daptomycin composition over time as a measure of the reconstituted Daptomycin chemical stability in a liquid form. As used herein, unless otherwise defined, the term "accelerated storage conditions" refers to storage of Daptomycin at about 40°C at about 75% relative humidity or at about 25°C at about 60% relative humidity. In particular, the formulations of the present invention were stored under accelerated storage conditions for a period of at least 6 months, which then typically allows to predict or extrapolate corresponding stability data where the formulations are stored at room temperature in long-term conditions.

In some embodiments, the lyophilized formulation of the present invention have a shelf life of at least about 12 months to about 4 years. The shelf life can be at any temperature, including, for example, room temperature and refrigeration (i.e., 2-8° C.). As used herein, “shelf life” or “shelf stable” means the period beginning from manufacture of a formulation beyond which the formulation cannot be expected beyond reasonable doubt to yield the therapeutic outcome approved by a government regulatory agency. In some embodiments, the reconstituted formulations described herein can be stable for or be stored at refrigerated temperatures (i.e., 2°C to 8°C) for about 2 hours to about 6 days, prior to administration to a subject. In some embodiments, the reconstituted formulations described herein can be stable for or be stored at room temperatures (i.e., 20°C to 25°C) for about 2 hours to about 3 days, prior to administration to a subject.

In embodiments, the present invention relates to a stable lyophilized Daptomycin formulation, wherein the said lyophilized formulation can be reconstituted in less than about 1.5 minutes. In embodiments, the present invention relates to a stable reconstituted formulation of a lyophilized Daptomycin formulation, wherein the Daptomycin formulation exhibits less “known impurities” of Daptomycin after exposure to accelerated storage conditions for about 6 months when compared to reference product (Cubicin RF) that is exposed to accelerated storage conditions. Preferably the formulations of the present invention exhibits less than about 5% of “known impurities” of Daptomycin after exposure to accelerated storage conditions for about 6 months. More preferably, the formulations of the present invention exhibits less than about 4% of “known impurities” of Daptomycin after exposure to accelerated storage conditions for about 6 months.

In embodiments, the present invention relates to stable pharmaceutical composition comprising: a) providing a stable lyophilized Daptomycin formulation comprising (i) Daptomycin, (ii) Arginine or its salts in the range of about 250 to about 650 mg/vial (iii) sodium hydroxide and (iv) water for injection, wherein the formulation has a pH of 6.6 to 7.2; b) reconstituting the said lyophilized formulation with a pharmaceutically acceptable diluent, wherein the said lyophilized formulation can be reconstituted in less than about 1.5 minutes; and c) administering the stable reconstituted Daptomycin to the human by intravenous administration.
The formulation of the present invention may be prepared by a simple process comprising the following steps:

1. Collect 80% of water for injection in to a clean vessel.
2. To step 1 add dispensed quantity of Mannitol/Dextran 40/ Sorbitol/ Hydroxypropyl Betadex/ Betadex Sulfobutyl Ether Sodium/ Glycine/ L-Histidine/ Polyethylene glycol 3350/ Polyvinylpyrrolidone/ Arginine Hydrochloride. Stir to get a clear solution.
3. To step 2 slowly add dispensed quantity of Daptomycin in small increments under continuous stirring. Stir to get clear solution. Check pH of the solution.
4. Adjust the pH of step 3 with Sodium hydroxide solution to get a pH (limit 6.6 -7.2). After adjusting pH, continue to stir for 10 minutes.
5. Make up the solution to100% of batch size using cool Water for injection and stir for 10minutes. Check the pH (Limit 6.6 – 7.2).
6. Filter step 5 bulk solution through 0.2µ filter and fill the solution into the clean and depyrogenated clear tubular vials and half stopper the vials and load into the lyophilizer.
7. After lyophilization stopper the vials under partial vacuum and seal immediately using flip off seals.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. The following examples are intended to serve as illustrations of the present invention and not intended to be limiting in any manner.
EXAMPLES
Example 1:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Mannitol Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 2:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Dextran 40 Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 3:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Sorbitol Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 4:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 HydroxypropylBetadex Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 5:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 BetadexSulfobutyl Ether Sodium Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 6:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Glycine Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 7:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 L-Histidine Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 8:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 L-Arginine Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 9:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Polyethylene glycol 3350 Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 10:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Polyvinylpyrrolidone Quantity will be optimized Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 11:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Arginine
Hydrochloride 500 mg Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Example 12:

S. No Ingredients Qty/vial Function
1 Daptomycin 500 mg Active Ingredient
2 Arginine
Hydrochloride 325 mg Stabilizer
3 Sodium hydroxide q.s to adjust pH pH Adjuster
4 Water for injection* q.s Solvent

Stability of Daptomycin for Injection was evaluated at different storage conditions by various parameters such as assay and impurities including major degradants i.e anhydro-Daptomycin, ß-isomer of Daptomycin and the lactone hydrolysis product. Comparative Stability data are available for the marketed product (Cubicin RF), Example 11 and Example 12 of the present invention, for different storage periods at 40ºC/75% Relative Humidity and at 25ºC/60% Relative Humidity. The below Tables 1, 2 and 3 shows the said comparative stability data.

Table 1
Stability Parameters at Room temperature (Initial Samples):
Stability Parameters CUBICIN® RF Example 11 Example 12
Storage Period (Months) Zero Time
Known
Impurities Lactone hydrolysis 0.94% 0.44% 0.29%
B-Isomer 1.03% 0.03% 0.09%
Anhydro Daptomycin 1.58% 0.86% 0.59%
Total 3.55% 1.33% 0.97%
Max Unknown impurities 0.8% 0.07% 0.06%
Total impurities 5.9% 1.53% 1.15%
Assay 94.2% 95.8% 99.9%

Table 2
Stability Parameters at 40ºC/75% Relative Humidity:
Stability Parameters CUBICIN® RF Example 11 Example 12
Storage Period (Months) 3 4.5 3 6 3 4.5 6
Known
Impurities Lactone hydrolysis 1.40% 1.49% 1.27% 1.66% 1.67% 2.17% 2.59%
B-Isomer 1.02% 1.01% 0.15% 0.16% 0.10% 0.11% 0.08%
Anhydro Daptomycin 1.75% 1.77% 1.14% 1.19% 0.86% 0.93% 1.30%
Total 4.17% 4.27% 2.56% 3.01% 2.63% 3.21% 3.97%
Max Unknown impurities 0.84% 0.83% 0.06% 0.05% 0.08% 0.10% 0.11%
Total impurities 6.73% 8.18% 2.72% 3.32% 2.85% 3.59% 4.38%
Assay 93.90% 92.50% 94.00% 95.50% 99.10% 96.10% 95.90%

Table 3
Stability Parameters at 25ºC/60% Relative Humidity:
Stability Parameters CUBICIN® RF Example 11 Example 12
Storage Period (Months) 3 3 6 3 6
Known
Impurities Lactone hydrolysis 1.01% 0.56% 0.72% 0.62% 0.80%
B-Isomer 1.07% 0.14% 0.16% 0.11% 0.10%
Anhydro Daptomycin 1.59% 0.80% 0.85% 0.59% 0.63%
Total 3.67% 1.50% 1.73% 1.32% 1.53%
Max Unknown impurities 0.83% 0.05% 0.05% 0.06% 0.17%
Total impurities 6.35% 1.60% 1.83% 1.52% 1.97%
Assay 93.00% 94.50% 97.70% 100.60% 95.30%

Further the reconstitution times are evaluated at room temperature for the marketed product (Cubicin RF), Example 11 and Example 12 products of the present invention. The below Table 4 shows the comparative reconstitution times.

Table 4
Product CUBICIN® RF Example 11 Example 12
pH 6.21 6.58 6.74
Reconstitution time 50 Seconds 80 Seconds 90 Seconds

Furthermore the reconstitution times are evaluated for the marketed product (Cubicin RF), Example 11 and Example 12 products of the present invention, which are exposed to accelerated storage conditions. The below Table 5 shows the comparative reconstitution times of the lyophilized formulations which are exposed to 40ºC/75% Relative Humidity for about 3 months.

Table 5
Product CUBICIN® RF Example 11 Example 12
pH 6.623 6.51 6.35
Reconstitution time 90 Seconds 60 Seconds 55 Seconds

Daptomycin formulation with Arginine Hydrochloride found be chemically stable and reconstituted in less than about 1.5 minutes when compared with marketed/reference product (Cubicin RF). Based on the study, it can be concluded that the formulation maintains the stability of the drug product and provide good reconstitution times.

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

1. A stable lyophilized formulation, comprising therapeutically effective amount of Daptomycin or pharmaceutically acceptable salts or solvates thereof and one or more stabilizers selected from the group consisting of mannitol, dextran 40, sorbitol, hydroxypropyl betadex, betadex sulfobutyl ether sodium, glycine, l-histidine, Arginine, polyethylene glycol 3350 and polyvinylpyrrolidone or their salts, or a combination thereof and mixtures thereof.

2. The lyophilized formulation according to claim 1, further comprises a pH adjusting agent, water for injection, optionally a preservative and a buffering agent.

3. The lyophilized formulation according to claim 1, wherein stabilizers is in the range of about 5 to 800 mg/vial.

4. The lyophilized formulation according to claim 1, wherein the said formulation is reconstituted with a pharmaceutical diluent prior to administration.

5. The formulation according to claim 4, wherein the lyophilized formulation is reconstituted with a diluent selected from sterile water for injection, bacteriostatic water for injection, sterile sodium chloride for injection, and Ringer's solution thereof.

6. The formulation according to claim 1 or 4, exhibits less “known impurities” of Daptomycin after exposure to accelerated storage conditions for about 6 months when compared to reference product (Cubicin RF).

7. The formulation according to claim 4, wherein the reconstitution time less than about 1.5 minute.

8. The formulation according to claim 4, wherein the said reconstituted formulation can be stored at different conditions and time periods.

9. A stable lyophilized formulation, comprising (i) Daptomycin, (ii) Arginine or its salts in the range of about 250 to about 650 mg/vial (iii) sodium hydroxide and (iv) water for injection.

10. A process for the preparation of a pharmaceutical composition according to claim 1, wherein the process comprises of the following steps:
(a) forming an aqueous solution of the said stabilizer with Daptomycin
(b) adjusting the pH of the liquid Daptomycin formulation to about 6.6 to 7.2; and
(c) converting the Daptomycin formulation to the solid formulation (e.g., lyophilization).