CLIAMS:1. A pre-lyophilized composition comprising bendamustine or its pharmaceutically acceptable salt, a pharmaceutically acceptable carrier, an organic solvent and water.
2. The pre-lyophilized composition according to claim 1, wherein the organic solvent is selected from group consisting of ethanol, n-propanol, n-butanol, acetontirile, dimethylsulfoxide, acetone or combination thereof.
3. The pre-lyophilized composition according to claim 1, wherein the organic solvent is ethanol.
4. A pre-lyophilized composition comprising about 20 mg/ml bendamustine hydrochloride, about 34mg/ml mannitol and about 20% v/v ethanol.
5. A stable pharmaceutical composition comprising bendamustine hydrochloride, said composition prepared from the pre-lyophilized composition according to any one of claims 1-4.
6. The stable pharmaceutical composition according to claim 5 having water content not more than about 5%w/w.
7. The stable pharmaceutical composition according to claim 5 having reconstitution time less than about 5 minutes.
8. The stable pharmaceutical composition according to claim 5 having a pH in the range from about 2.5 to about 4.5.
9. The stable pharmaceutical composition of bendamustine according to claim 5 having ethylester impurity content not more than about 1%w/w.
10. A process of preparing a stable pharmaceutical composition according to claim 5, said process comprising:
a. adding pharmaceutically acceptable carrier into vessel containing water for injection (WFI) under continuous stirring to obtain a visibly clear solution, (Composition I);
b. dispersing bendamustine hydrochloride in an appropriate quantity of organic solvent under continuous stirring to form pale yellow suspension, and then adding appropriate quantity of water for injection (WFI) under continuous stirring, (Composition II);
c. Filling composition I and composition II into vials, partially stoppering (autoclaved and dried) with rubber stopper and maintaining temperature between 2° to 8°C
d. Lyophilizing the vials to obtain a stable pharmaceutical composition. ,TagSPECI:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)

&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
(See section 10 and rule 13)

Title: PHARMACEUTICAL COMPOSITION COMPRISING BENDAMUSTINE

Applicant:
GLENMARK PHARMACEUTICALS LIMITED,
An Indian Company registered under
The Companies Act, 1956, India
and having its office at
Glenmark House, HDO – Corporate Bldg,
Wing A, B. D. Sawant Marg,
Chakala, Andheri (East),
MUMBAI – 400 099

The following specification describes the invention and the manner in which it is to be performed.

PHARMACEUTICAL COMPOSITION COMPRISING BENDAMUSTINE

FIELD OF THE INVENTION
The present patent application relates to a pharmaceutical composition comprising bendamustine or its pharmaceutically acceptable salt. Particularly, the present patent application relates to a stable pharmaceutical composition for parenteral administration comprising bendamustine or its pharmaceutically acceptable salt and a pharmaceutically acceptable carrier; a process for preparing such composition; and its use in the treatment of cancer.

BACKGROUND OF THE INVENTION
Bendamustine was first synthesized in 1963 by Ozegowski and Krebs. It was available in Germany from early 1970’s to 1992 under the brand name CYTOSTATAN®. Since 1993, bendamustine has been marketed under the trade name RIBOMUSTIN® in Germany by Mundipharma International Corporation Limited. It has been widely used as a single-agent or in combination with other anti-cancer agents for the treatment of indolent non-Hodgkin's lymphoma (NHL), multiple myeloma, and chronic lymphocyte leukemia (CLL).
Bendamustine has been reported as a highly unstable compound due to its degradation in aqueous solution. In order to prevent its degradation tendency, bendamustine has been supplied as a lyophilized product. Ribomustin® is a lyophilized formulation which contains bendamustine HCl and mannitol in a sterile lyophilized form as a white powder for intravenous use following reconstitution.
U.S. Patent Publication No.2006/0159713 discloses a lyophilized formulation of bendamustine. This lyophilized formulation of bendamustine is prepared by lyophilizing a pre-lyophilizing solution comprising bendamustine, tertiary butyl alcohol, mannitol and water.
In the US, bendamustine is sold under the trade name TREANDA®, approved for treatment of chronic lymphocytic leukemia (CLL) and indolent B-cell non-Hodgkin's lymphoma (NHL) that has progressed during or within six months of treatment with rituximab or a rituximab-containing regimen. TREANDA® contains bendamustine hydrochloride and mannitol, which is supplied as a sterile non-pyrogenic white to off-white powder for intravenous use following reconstitution. Treanda® is formulated as lyophilized powder for injection with 25mg bendamustine and 100mg bendamustine.
PCT publication No WO/2012/103226 discloses a lyophilized bendamustine formulations prepared by using of an organic solvent with water, as pre-lyophilization bulk solvent systems, wherein such organic solvents do not include tertiary-butanol or ethanol.
Thus, there is a need to develop a stable lyophilized composition of bendamustine.

SUMMARY OF THE INVENTION
The present invention relates to a stable pharmaceutical composition comprising bendamustine or its pharmaceutically acceptable salt.
The inventors of present invention have unexpectedly found that the formation of bendamustine ethyl ester impurity is controlled when bendamustine is dissolved in a particular range of concentration in a specific solvent before lyophilization.
The present invention relates to a pre-lyophilized composition comprising bendamustine or its pharmaceutically acceptable salt, a pharmaceutically acceptable carrier, organic solvent and water.
In an embodiment, the organic solvent is selected from group consiting of ethanol, n-propanol, n-butanol, acetontirile, dimethylsulfoxide, acetone or combination thereof.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, pharmaceutically acceptable carrier, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, mannitol, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, mannitol, n-butanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, mannitol, acetone, and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, sucrose, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine hydrochloride, sorbitol, n-propanol and water.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v ethanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v n-butanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v acetone.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml sucrose and from about 10% v/v to about 30% v/v ethanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml sorbitol and from about 10% v/v to about 30% v/v n-propanol.
In an embodiment, the pre-lyophilized composition comprises from about 10 mg/ml to about 30 mg/ml bendamustine, from about 25mg/ml to about 40mg/ml mannitol and from about 15% v/v to about 25% v/v ethanol.
In a preferred embodiment, the pre-lyophilized composition comprises about 20 mg/ml bendamustine hydrochloride, about 34mg/ml mannitol and about 20% v/v ethanol.
In another embodiment of the present invention, the pre-lyophilized composition can be in the form of a solution or dispersion which is suitable for lyophilization. Preferably, the pre-lyophilized composition is in the form of solution.
In another embodiment of the present invention, the pH of the pre-lyophilized composition ranges from about 2 to 5, or preferably from about 2.5 to 4.5.
The present invention also relates to a stable pharmaceutical composition obtained after lyophilizing the pre-lyophilized composition described herein. The stable pharmaceutical composition is a lyophilized product comprises bendamustine and pharmaceutically acceptable carrier.
The present invention also relates to a process of preparing a stable pharmaceutical composition which is a lyophilized product, said process comprising:
1) Adding pharmaceutically acceptable carrier into vessel containing water for injection (WFI) under continuous stirring to obtain a visibly clear solution, (Composition I)
2) Dispensing appropriate quantity of organic solvent into another mixing vessel, adding appropriate quantity of Bendamustine or its salt thereof under continuous stirring, to form pale yellow suspension, then adding appropriate quantity of water for injection (WFI) under continuous stirring, (Composition II)
3) Filling composition I and composition II into Vials, partially stoppering (autoclaved and dried) with rubber stopper and maintaining temperature between 2° to 8°C
4) Loading the partially stoppered vials into pre cooled chamber of lyophilizer at -10°C and closing the chamber for lyophilization process.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having water content not more than about 5%w/w or preferably not more than about 2%w/w.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having reconstitution time less than about 5 minutes or preferably less than about 3 minutes.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having a pH in the range from about 2.5 to about 4.5.
In another embodiment of the present invention, the stable pharmaceutical composition contains not more than about 1%w/w, or preferably not more than about 0.5%w/w bendamustine hydroxy impurity.
In another embodiment of the present invention, the stable pharmaceutical composition contains not more than about 1%w/w, or preferably not more than about 0.5%w/w bendamustine ethylester impurity.
In another embodiment of the present invention, the stable pharmaceutical contains not more than about 2%w/w, or preferably not more than about 1%w/w total impurity.
In another embodiment the invention provides a method of treating a medical condition in a patient that involve administering a therapeutically effective amount of a sable pharmaceutical composition of the invention where the condition is amenable to treatment with said pharmaceutical composition. Some conditions amenable to treatment with the compositions of the invention include chronic lymphocytic leukemia (CLL), Hodgkin's disease, non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), breast cancer, small cell lung cancer, hyperproliferative disorders, and an autoimmune disease.

DETAILED DESCRIPTION OF THE INVENTION
Definitions
The term "bendamustine" refers to the compound called bendamustine, pharmaceutically acceptable salts of bendamustine, isomers, racemates, solvates, complexes and hydrates, anhydrate forms thereof, and any polymorphic or amorphous forms thereof or combinations thereof.
The term "stable pharmaceutical composition" refers to a pharmaceutical composition of bendamustine having sufficient stability to allow storage at a convenient temperature, such as between about 10°C to about 25°C for a period of time, such as at least about six months, at least about one year, or at least about 2 years.
Further the term "stable pharmaceutical composition" also refers to a pharmaceutical composition of bendamustine having sufficient stability to allow storage at a temperature, such as between about 35°C to about 50°C for a period of time, such as at least about one month or at least about six month.
The term “salt” or “pharmaceutically acceptable salt”, it is meant those salts and esters which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, and allergic response, commensurate with a reasonable benefit to risk ratio, and effective for their intended use. Representative acid additions salts include the hydrochloride, furoate, hydrobromide, sulphate, bisulphate, acetate, oxalate, valerate, oleate, palmitate, stearate, laurate, borate, benzoate, lactate, phosphate, tosylate, mesylate, citrate, maleate, fumarate, succinate, tartrate, ascorbate, glucoheptonate, lactobionate, and lauryl sulphate salts. Representative alkali or alkaline earth metal salts include the sodium, calcium, potassium and magnesium salts.
The term “pre-lyophilizing composition” as used herein refers to solution or dispersion wherein bendamustine or its acceptable salt (preferably hydrochloride) is either completely or partially solubilized or dispersed in a solvent composed of aqueous and one or more non-aqueous solvents, more preferably the non-aqueous solvent is ethanol.
The term "lyophilized product" as used herein refers to solid material obtained by lyophilization, i.e. freeze-drying a solution composed of aqueous and one or more non-aqueous solvents, more preferably the non-aqueous solvent is ethanol.
The term "pharmaceutically acceptable carrier" as used herein refers to substance which is pharmaceutically acceptable and is used to formulate a pharmaceutical composition of bendamustine or its salt. Preferably, a carrier is therapeutically inert material which includes but not limited to stabilizers, bulking agents, buffers, carriers, diluents, vehicles, and solubilizer. The pharmaceutically acceptable carrier useful for the present application include, but not limited to mannitol, sorbitol, lactose, sucrose, maltose, dextrose, trehalose, sodium or potassium phosphate, citric acid and tartaric acid. Other carriers that may be used, if desired, include antioxidants, such as, but not limited to ascorbic acid, acetylcysteine, cysteine, sodium hydrogen sulfite, butylated hydroxyanisole, butylated hydroxytoluene, alpha-tocopherol acetate, and chelating agents.
As used herein, the term “treating” or “treatment” of a state, disorder or condition mean: (1) inhibiting the state, disorder or condition, i.e., arresting or reducing the development of the disease or at least one clinical or sub-clinical symptom thereof, or (2) relieving the disease, i.e., causing regression of the state, disorder or condition or at least one of its clinical or sub-clinical symptoms. The benefit to a subject to be treated is either statistically significant or at least perceptible to the subject or to the physician.
The term "therapeutically effective amount" as used herein refers to that amount of the compound being administered that will relieve to some extent one or more of the symptoms of the disorder being treated. Further, therapeutically effective amount can be that amount that increases the life expectancy of a patient afflicted with a terminal disorder.
The present invention relates to a stable pharmaceutical composition comprising bendamustine or its pharmaceutically acceptable salts, isomers, racemates, enantiomers, hydrates, solvates, metabolites, polymorphs, and mixtures thereof.
The present invention relates to a pre-lyophilized composition comprising bendamustine or its pharmaceutically acceptable salt, pharmaceutically acceptable carrier, organic solvent and water.
In an embodiment, the organic solvent is selected from group consisting of ethanol, n-propanol, n-butanol, acetontirile, dimethyl sulfoxide, acetone or combination thereof.
In an embodiment, the pre-lyophilized composition comprises bendamustine, pharmaceutically acceptable carrier, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine, mannitol, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine, mannitol, n-butanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine, mannitol, acetone, and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine, sucrose, ethanol and water.
In an embodiment, the pre-lyophilized composition comprises bendamustine, sorbitol, n-propanol and water.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v ethanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v n-butanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml mannitol and from about 10% v/v to about 30% v/v acetone.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml sucrose and from about 10% v/v to about 30% v/v ethanol.
In an embodiment, the pre-lyophilized composition comprises from about 5 mg/ml to about 40 mg/ml bendamustine, from about 20mg/ml to about 50mg/ml sorbitol and from about 10% v/v to about 30% v/v n-propanol.
In an embodiment, the pre-lyophilized composition comprising about 10 mg/ml to about 30 mg/ml bendamustine, about 25mg/ml to about 40mg/ml mannitol and about 15% v/v to about 25% v/v ethanol.
In a preferred embodiment, the pre-lyophilized composition comprising about 20 mg/ml bendamustine hydrochloride, about 34mg/ml mannitol and about 20% v/v ethanol.
In another embodiment of the present invention, the pre-lyophilized composition can be in the form of a solution or dispersion which is suitable for lyophilization. Preferably, the pre-lyophilized composition is in the form of solution.
In another embodiment of the present invention, the pH of the pre-lyophilized composition ranges from about 2 to 5, or preferably from about 2.5 to 4.5.
In another embodiment, the pre-lyophilized composition further comprises pharmaceutical acceptable carrier.
The present invention also relates to a stable pharmaceutical composition obtained after lyophilizing the pre-lyophilized composition described herein. The stable pharmaceutical composition is a lyophilized product comprises bendamustine and pharmaceutically acceptable carrier.
The present invention also relates to a process of preparing a stable pharmaceutical composition which is a lyophilized product, said process comprising:
1) Adding pharmaceutically acceptable carrier into vessel containing water for injection (WFI) under continuous stirring to obtain a visibly clear solution, (Composition I)
2) Dispensing appropriate quantity of organic solvent into another mixing vessel, adding appropriate quantity of Bendamustine or its salt thereof under continuous stirring, to form pale yellow suspension, then adding appropriate quantity of water for injection (WFI) under continuous stirring, (Composition II)
3) Filling composition I and composition II into Vials, partially stoppering (autoclaved and dried) with rubber stopper and maintaining temperature between 2° to 8°C
4) Loading the partially stoppered vials into pre cooled chamber of lyophilizer at -10°C and close the chamber for lyophilization process.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having water content not more than about 5%w/w or preferably not more than 2%w/w.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having reconstitution time less than about 5 minutes or preferably less than about 3 minutes.
In another embodiment of the present invention, the stable pharmaceutical composition of bendamustine having a pH in the range from about 2.5 to about 4.5.
In another embodiment of the present invention, the stable pharmaceutical composition contains not more than about 1%w/w, or preferably not more than about 0.5%w/w bendamustine hydroxy impurity.
In another embodiment of the present invention, the stable pharmaceutical composition contains not more than about 1%w/w, or preferably not more than about 0.5%w/w bendamustine ethylester impurity.
In another embodiment of the present invention, the stable pharmaceutical contains not more than about 2%w/w, or preferably not more than about 1%w/w total impurity.
Another embodiment of the invention is a method of treating a cancer in a patient that involves administering a therapeutically effective amount of a pharmaceutical composition of the present invention. Some cancer conditions amenable to such treatment include chronic lymphocytic leukemia (CLL), Hodgkin's disease, non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), breast cancer, small cell lung cancer, hyperproliferative disorders, and an autoimmune disease.
The pre-lyophilization composition can be sterilized before lyophilization. Sterilization is generally performed by aseptic filtration, e.g., through a 0.22 micron or less filter.
Sterilization of the pre-lyophilized composition can be achieved by other methods known in the art, e.g., filtration, radiation.
In the present invention, the pre-lyophilizing composition is lyophilized after sterilization. The formulation can be effectively and efficiently lyophilized in the containers in which the product is to be marketed, such as, a vial.
Another aspect of the invention is a method for preparing a lyophilized product of bendamustine by lyophilizing the pre-lyophilization composition comprising the steps of-
i) freezing the pre-lyophilization composition to a temperature below about -40°C, preferably -50°C, to form a frozen solution;
ii) ramping the frozen solution at or below -40°C, for at least 2 hours to about 4 hours
iii) holding the frozen solution at or below -50°C, for about 10 hours to 15 hours;
iv) ramping the frozen solution to a primary drying temperature between about -50°C and about -5°C. to form a dried solution;
v) holding for about 10 to about 60 hours;
vi) ramping the dried solution to a secondary drying temperature between about 25°C. and about 40°C; and
vii) holding for about 5 to about 20 hours to form a bendamustine lyophilized product.
Preferably, the method of lyophilizing the pre-lyophilization composition comprises the following steps-
i) freezing the pre-lyophilization composition at or below -40°C to form a frozen solution;
ii) ramping the frozen solution at or below -40°C, for at least 2 hours
iii) holding the frozen solution at about -50°C for about 10 hours;
iv) ramping to a primary drying temperature between about -40°C and about -5°C to form a dried solution;
v) holding at a primary drying temperature for about 20 to about 40 hours;
vi) ramping the dried solution to a secondary drying temperature between about 25°C and about 40°C; and
vii) holding at a secondary drying temperature for at least 6 hours up to about 12 hours.
It will be understood that one skilled in the art can change the order of the steps and quantities as needed.
The following examples are provided to enable one skilled in the art to practice the invention and are merely illustrative of the invention. The examples should not be read as limiting the scope of the invention.

EXAMPLES
EXAMPLES 1-5: Compositions of bendamustine hydrochloride for parenteral administration.
Ingredients Quantity/Unit (Qty per vial in mg)
1 2 3 4 5
D-Mannitol - 170 - 170 170
Sorbitol 170 - - - -
Sucrose - - 170 - -
Water for Injection1 q.s to 3.5 ml q.s to 3.5 ml q.s to 3.5 ml q.s to 3.5 ml q.s to 3.5 ml
Bendamustine HCl 100 100 100 100 100
Ethanol1 - 1 ml 1 ml - -
n-propanol1 1 ml - - - -
n-butanol1 - - - 1 ml -
Acetone1 - - - - 1 ml
Water for Injection1 q.s to 1.5 ml q.s to 1.5 ml q.s to 1.5 ml q.s to 1.5 ml q.s to 1.5 ml
q.s.: Quantity sufficient; 1does not appear in the final product.

EXAMPLES 6-10: Compositions of Bendamustine Hydrochloride for parenteral administration.
Ingredients Quantity/Unit (Qty per vial in mg)
6 7 8 9 10
D-Mannitol - 42.5 - 42.5 42.5
Sorbitol 42.5 - - - -
Sucrose - - 42.5 - -
Water for Injection1 q.s to 0.875 ml q.s to 0.875 ml q.s to 0.875 ml q.s to 0.875 ml q.s to 0.875 ml
Bendamustine HCl 25 25 25 25 25
Ethanol1 - 0.25 ml 0.25 ml - -
n-propanol1 0.25 ml - - - -
n-butanol1 - - - 0.25 ml -
Acetone1 - - - - 0.25 ml
Water for Injection1 q.s to 0.375 ml q.s to 0.375 ml q.s to 0.375 ml q.s to 0.375 ml q.s to 0.375 ml
q.s.: Quantity sufficient; 1does not appear in the final product.

Manufacturing procedure for EXAMPLES 1-10:
1. Mannitol was added to the manufacturing vessel under continuous stirring containing water for injection (WFI) to obtain a visibly clear solution, while adding mannitol in above vessel the stirring was maintained at 800-1000 RPM, for 5-10 minutes for complete dissolution, the volume was made up with WFI (Composition I)
2. Organic solvent was dispensed into another mixing vessel, Bendamustine Hydrochloride was added under continuous stirring, while adding drug in this vessel, the stirring was maintained at 1000-1500 RPM, for 3-5 minutes to form pale yellow suspension, then WFI was added at RT under continuous stirring, while adding water in this vessel, the stirring was maintained at 1000-1500 RPM, for 3-5 minutes to form clear pale yellow solution, the volume was made up with WFI and then cooled at 2° to 8°C in Jacketed vessel. (Composition II)
3. Both compositions I and composition II were separately filtered using the PVDF filters for sterilization at 2° to 8°C under nitrogen pressure.
4. After filtration, composition I & composition II were filled into depyrogenated vials and then vials were partially stopperred (autoclaved and dried) with rubber stopper. During filling, temperature was maintained between 2° to 8°C
5. The partially stoppered vials were loaded into pre cooled chamber of lyophilizer at -10°C and then chamber was closed for lyophilization process.
6. The lyophilizer was operated as per specified lyophilization parameters as given below.
7. After completion of lyophilization cycle, the vials were stopperred in presence of nitrogen atmosphere, and vials were sealed and external cleaned of vials.

Lyophilization Cycle:
The lyophilization cycle as used in lyophilizing the pre-lyophilized solution of bendamustine is given below:
1. Freezing: Start the Freezing cycle as per schedule mentioned below:
a. The Shelf temperature was set to -10ºC and was maintained during vial loading.
b. The Shelf temperature was set to -40ºC. Ramped for 2 hrs.
c. The Shelf temperature was set to -50ºC. Ramped for 2 hrs with temperature margin and held for 8 hrs.
2. Primary drying: The condenser was started and the condenser temperature was maintained between -65°C to -70°C.
Start the primary drying as per schedule mentioned below:
a. Vacuum to 0.900 mbar was applied, shelf temp temperature was set to -40ºC. Ramped for 2 hrs and held for 2 hrs.
b. Vacuum to 0.800 mbar was applied, shelf temp temperature was set to -40ºC. Ramped for 1 hr and held for 3 hrs.
c. Vacuum to 0.500 mbar was applied, shelf temp temperature was set to -25ºC. Ramped for 2 hrs and held for 4 hrs.
d. Vacuum to 0.200 mbar was applied, shelf temp temperature was set to -25ºC. Ramped for 2 hrs and held for 8 hrs.
e. Vacuum to 0.200 mbar was applied, shelf temp temperature was set to -15ºC. Ramped for 2 hrs and held for 6 hrs.
f. Vacuum to 0.200 mbar was applied, shelf temp temperature was set to -5ºC. Ramped for 2 hrs and held for 6 hrs.
g. Vacuum to 0.200 mbar was applied, shelf temperature was set to 10ºC. Ramped for 2 hrs and held for 4 hrs.
3. Secondary drying:
The vacuum below 0.100 mbar was maintained throughout secondary drying cycle.
The secondary drying was started as per schedule mentioned below:
a. The shelf temperature to 25ºC was set. Ramped for 2 hrs and held for 2 hrs.
b. The shelf temp to 40ºC was set. Ramped for 2 hrs and held for 4 hrs.

EXAMPLE 11: Stability data of Bendamustine composition as per Example 2 (100mg/vial) and Example 7 (25mg/vial).
Storage Condition: 25ºC/60% Relative Humidity
Pack Details:
Example 2 - 20ml amber tubular glass vial USP type 1 with chlorobutyl stopper
Example 7 - 10ml amber tubular glass vial USP type 1 with chlorobutyl stopper
Tests Example 2 Composition (100mg/vial) Example 7 Composition
(25mg/vial)
6 month 12 month 6 month 12 month
Description White lyophilized cake White lyophilized cake White lyophilized cake White lyophilized cake
Water content (w/w) 1% <1% 1% 1%
Reconstitution time 2.2 min. 2.2 min. 0.2 min. 0.4 min.
pH of reconstituted solution 2.8 3.0 2.8 2.6
Impurity Profile (w/w)
N-alkylated
Monohydroxy
Ethylester
Dimer
Any unspecified impurity
Total Impurity
0.03%
0.18%
<0.1%
0.21%
0.03%

0.51%
0.05%
0.21%
--
0.37%
0.05%

0.84%
0.05%
0.19%
<0.1%
0.24%
0.06%

0.59%
0.17%
0.19%
--
0.26%
0.10%

0.99%
Assay (w/w) 97.3% 96.4% 96.9% 93.0%

EXAMPLE 12: Stability data of Bendamustine composition as per Example 2 (100mg/vial) and Example 7 (25mg/vial).
Storage Condition: 40ºC/75% Relative Humidity
Pack Details:
Example 2 - 20ml amber tubular glass vial USP type 1 with chlorobutyl stopper
Example 7 - 10ml amber tubular glass vial USP type 1 with chlorobutyl stopper
Tests Example 2 Composition (100mg/vial) Example 7 Composition
(25mg/vial)
1 month 3 month 1 month 3 month
Description White lyophilized cake White lyophilized cake White lyophilized cake White lyophilized cake
Water content (w/w) 1% 1% 2% 1%
Reconstitution time 1.2 min. 2.2 min. 0.2 min. 0.6 min.
pH of reconstituted solution 3.0 3.1 3.3 3.0
Impurity Profile (w/w)
N-alkylated
Monohydroxy
Ethylester
Dimer
Any unspecified impurity
Total Impurity
0.04%
0.15%
<0.1%
0.24%
0.09%

0.63%
0.03%
0.10%
<0.1%
0.22%
0.04%

0.52%
0.05%
0.16%
0.1%
0.28%
0.10%

0.71%
0.04%
0.14%
0.1%
0.25%
0.06%

0.68%
Assay (w/w) 96.9% 96.9% 98.3% 95.1%

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and application of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as described above.
All publications, patents, and patent applications cited in this application are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference.

CLAIMS

We claim:

1. A pre-lyophilized composition comprising bendamustine or its pharmaceutically acceptable salt, a pharmaceutically acceptable carrier, an organic solvent and water.
2. The pre-lyophilized composition according to claim 1, wherein the organic solvent is selected from group consisting of ethanol, n-propanol, n-butanol, acetontirile, dimethylsulfoxide, acetone or combination thereof.
3. The pre-lyophilized composition according to claim 1, wherein the organic solvent is ethanol.
4. A pre-lyophilized composition comprising about 20 mg/ml bendamustine hydrochloride, about 34mg/ml mannitol and about 20% v/v ethanol.
5. A stable pharmaceutical composition comprising bendamustine hydrochloride, said composition prepared from the pre-lyophilized composition according to any one of claims 1-4.
6. The stable pharmaceutical composition according to claim 5 having water content not more than about 5%w/w.
7. The stable pharmaceutical composition according to claim 5 having reconstitution time less than about 5 minutes.
8. The stable pharmaceutical composition according to claim 5 having a pH in the range from about 2.5 to about 4.5.
9. The stable pharmaceutical composition of bendamustine according to claim 5 having ethylester impurity content not more than about 1%w/w.
10. A process of preparing a stable pharmaceutical composition according to claim 5, said process comprising:
a. adding pharmaceutically acceptable carrier into vessel containing water for injection (WFI) under continuous stirring to obtain a visibly clear solution, (Composition I);
b. dispersing bendamustine hydrochloride in an appropriate quantity of organic solvent under continuous stirring to form pale yellow suspension, and then adding appropriate quantity of water for injection (WFI) under continuous stirring, (Composition II);
c. Filling composition I and composition II into vials, partially stoppering (autoclaved and dried) with rubber stopper and maintaining temperature between 2° to 8°C
d. Lyophilizing the vials to obtain a stable pharmaceutical composition.

Dated this 16th day of April 2014.

Signature________________________
Mr. Taranpreet Singh Lamba
Vice President – IPM
Glenmark Pharmaceuticals Ltd

ABSTRACT

The present invention relates to a pre-lyophilized composition comprising bendamustine or its pharmaceutically acceptable salt, a pharmaceutically acceptable carrier, an organic solvent and water. Furthermore, the present invention provides a stable pharmaceutical composition comprising bendamustine hydrochloride prepared from such pre-lyophilized composition, a process for preparing such composition; and its use in the treatment of cancer.