FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents [Amendment] Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
Novel Crystalline Form Of Epirubicin Hydrochloride And Process Thereof
2. APPLICANT
NAME : Sterling Biotech Limited
NATIONALITY : IN
ADDRESS : 43, Atlanta Building, Nariman Point, Mumbai - 400021
3. PREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention in general relates to crystalline form of Epirubicin hydrochloride, which is useful as an anti-cancer chemotherapeutic drug.
In particular, this invention relates to novel crystalline form of Epirubicin hydrochloride, which is characterized by the distinct characterstics as described herein. The present invention also relates to the novel crystalline polymorphic form which is obtained in a substantially pure form. The present invention also relates to the process for preparing the said novel crystalline form of Epirubicin hydrochloride which is substantially free of impurities.
BACKGROUND OF INVENTION
Anthracyclines form one of the largest families of naturally occurring bioactive compounds derived from Streptomyces bacteria. These compounds are used to treat wide range of cancers including leukemias, lymphomas, breast, uterine, ovarian and lung cancers. These include Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Pirarubicin, Zorubicin, Aclarubicin and Carminomycin.
Epirubicin hydrochloride chemically known as (8S, 10S)-10-[(3-Amino-2,3,6-trideoxy-α-L-arabino-hexopyranosyl)oxy)]-6,8,11 -trihydroxy-8-(hydroxyacetyl)-1 -methoxy-7,8,9,10-tetrahydrotetracene-5,12-dione hydrochloride is represented by the formula:


The preparation of Epirubicin hydrochloride has been disclosed US 4,058,519, 4,112,076, 4,861,870, 5,945,518, 5,874,550, IT 1,237,202, EP 0848009, JP 2007261976 and US 20070142309. All the described processes when practiced invariably provide amorphous forms of Epirubicin hydrochloride hence are associated with the inherent drawbacks of handling amorphous Epirubicin hydrochloride such as reproducibility and stability.
US 7,485,707 describes crystalline form "Type-II" of Epirubicin hydrochloride wherein they claim enhanced thermal stability. However the process when practiced is found to be invariably inconsistent in terms of producing the patented polymorph.
Thus, it is desirable to have a novel crystalline form of Epirubicin hydrochloride which can be produced in a reproducible manner at any scale, has considerable physical stability and purity.
SUMMARY OF THE INVENTION
The present invention relates to novel crystalline forms of Epirubicin hydrochloride SBL-1, SBL-2 and SBL-3 in particular 'SBL-3'. The crystalline form 'SBL-3' exhibits excellent reproducibility at any scale and enhanced physical stability. The crystalline Epirubicin hydrochloride of the present invention is characterized by powder X-ray diffraction having typical average values of diffraction angle (20) and relative intensity.
The present invention also provides a novel process for preparing crystalline forms of Epirubicin hydrochloride in substantially acceptable pure form.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The accompanying figures, which are included to provide a further understanding of the invention are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the detailed description serve to explain the principles of the invention. No attempt is made to show details of the invention and various ways in which it may be practiced.

Fig. 1: Illustrates a powder X-ray diffraction pattern for crystalline form 'SBL-l'of
Epirubicin hydrochloride.
Fig. 2; Illustrates a powder X-ray diffraction pattern for crystalline form 'SBL-2' of
Epirubicin hydrochloride.
Fig. 3: Illustrates a powder X-ray diffraction pattern for crystalline form 'SBL-3' of
Epirubicin hydrochloride.
Fig. 4: Illustrates a Drift Analysis for crystalline form 'SBL-3' of Epirubicin hydrochloride
Fig. 5: Illustrates a Differential Scanning Calorimetric Graph for crystalline form 'SBL-3'
of Epirubicin hydrochloride.
The objectives as mentioned above will be apparent in the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
It is understood that the invention is not limited to the particular methodology, protocol etc., described herein, as these may vary as the skilled artisan will recognize. It is also to be under stood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. It is also noted that as used herein and in the appended claims, singular forms "a", "an," and "the" include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to "a solvent" is a reference to one or more solvents and equivalents thereof known to those skilled in the art.
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the invention pertains. The embodiments of the invention and the various features and advantageous details thereof are described and/ or illustrated in the accompanying figures and detailed in the following description. It should be noted that the features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein.
Descriptions of well known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the invention. The examples used herein are intended merely to facilitate an understanding of ways in which the invention may be

practiced and to enable those of skill in the art to practice the embodiments of the invention. Accordingly the examples and embodiments herein should not be construed as limiting the scope of the invention, which is solely by the appended claims and applicable law.
Accordingly the present invention provides novel crystalline forms SBL-1, SBL-2 and SBL-3 of Epirubicin hydrochloride characterized by powder X-ray Diffraction pattern having typical average values of diffraction angle (20) and relative intensity as presented in Table 1.
Table 1

Sl.No
Crystalline polymorphic forms

"SBL-1" "SBL-2" "SBL-3"

Diffraction Angles
(2θ) Relative intensity
P% Diffraction Angles
(2θ) Relative intensity
P% Diffraction Angles
(2θ) Relative intensity
P%
1. 6.27 10.21 6.22 50.50 5.03 100.00
2 7.59 26.66 7.68 38.43 7.42 28.11
3 10.02 4.89 10.01 6.56 10.16 4.61
4 12.19 25.30 11.29 20.75 11.98 6.63
5 15.13 7.85 11.73 14.71 12.98 4.30
6 15.88 22.76 12.34 20.09 15.99 13.89
7 16.40 48.18 15.45 13.96 16.47 24.85
8 17.06 12.91 15.95 28.38 17.23 4.02
9 19.20 35.91 16.69 58.34 18.77 6.75
10 20.83 20.66 17.56 6.24 19.38 18.28
11 21.94 100.00 19.51 42.63 19.95 9.65
12 22.91 32.59 20.06 20.17 20.95 6.93
13 23.44 13.66 20.92 17.65 21.99 49.82
14 24.05 13.21 21.51 26.47 22.50 17.12
15 24.68 9.51 22.12 100.00 26.24 19.29
16 26.16 34.90 22.61 40.73 30.35 3.61

17
28.60 8.12 23.069 27.64 31.70 1.81
18 29.93 11.02 23.52 21.00 32.65 2.56
19 26.28 41.74 33.91 1.77
20 27.92 15.28 36.64 3.61
21 30.14 14.02 37.25 2.60
22 32.94 7.48
23 36.15 10.66
24 36.70 3.96
25 37.00 8.35
The invention further provides novel process for the preparation of the said crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' which is produced reproducibly at any scale with the desired chemical purity and possess considerable physical stability.
The present invention further provides novel crystalline forms in particular 'SBL-3' of Epirubicin hydrochloride wherein it is obtained in the desired chemical purity and substantially free from known impurities.
The present invention further provides novel crystalline forms in particular 'SBL-3' of Epirubicin hydrochloride which is stable i.e. resistant to polymorphic changes when exposed to temperature and humidity.
The present invention further provides a novel crystalline form in particular 'SBL-3' of Epirubicin hydrochloride wherein it is obtained by crystallization or precipitation or swapping from a suitable single or mixture of one or more water miscible or water immiscible solvent under suitable temperature conditions.
The present invention further provides a process for preparing novel crystalline form of Epirubicin hydrochloride in particular 'SBL-3' wherein the process for preparing the same comprises the steps of:

(i) dissolving Epirubicin hydrochloride in a single or mixture of suitable water miscible or immiscible solvent at suitable temperature, and
(ii) isolating the solid by concentrating the solution at a suitable temperature to furnish crystalline Epirubicin hydrochloride, or optionally
(iii) isolating the solid via filtration by either allowing the product to crystallize gradually from solution or by precipitating the solid by adding a suitable anti solvent.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the epirubicin hydrochloride used in step (i) is amorphous epirubicin hydrochloride.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable water miscible or immiscible solvents, used either alone or in combination, for dissolution, is chosen from C-l to C-8 linear or branched alcohols, halogenated solvents, ethereal solvents, esters or a mixture thereof.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable alcohol is chosen from methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol or a mixture thereof.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable halogenated solvents for dissolution is chosen from chloroform, dichloromethane, ethylene dichloride or a mixture
thereof.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable temperature range for dissolution is between 40 and 90°C.

The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable temperature for isolation by concentration is preferably between 40 and 90°C.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the suitable antisolvent used for precipitation is chosen from halogenated solvents, ethereal solvents, esters or a mixture thereof.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBLS' wherein the halogenated solvent is chosen from chloroform, dichloromethane, ethylene dichloride or a mixture thereof. The preferred halogenated solvent is dichloromethane.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the ethereal solvent is chosen from diethylether, diisopropylether, tertiarybutyldimethylether, dioxane, tetrahydrofuran or a mixture thereof. The preferred ethereal solvent is diisopropyl ether.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the ester is chosen from methyl acetate, ethylacetate, isopropyl acetate, tertiarybutyl acetate or a mixture thereof. The preferred ester is ethyl acetate.
The present invention further provides a process for preparing novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' wherein the crystallization, precipitation or swapping methodology employed for its isolation is performed with or without seeding.
Thus the present invention provides considerably stable novel crystalline forms of Epirubicin hydrochloride in particular 'SBL-3' which is easy to synthesize and produced consistently at the desired scale.

The following examples illustrate, but in no way limit the scopes of the novel process of this invention. Any deviation from this, apparent and obvious to a person skilled in the art of organic synthesis, forms part of this invention though not explicitly substantiated.
EXAMPLES:
Example 1 Preparation of crystalline form 'SBL-1' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in a mixture of n-butanol (200ml) and methanol (150ml) at room temperature was heated to 40-95° C for 10-15 minutes to get clear solution. Distill out the solvent completely under vacuum at 40-95° C. To the obtained solid was added again a mixture of n-butanol (100ml) and methanol (100ml) at 40-95° C and distill out the solvent completely under vacuum at 40-95° C. To the obtained solid was added again n-butanol (100ml) at 40-95° C and distill out the solvent completely under vacuum at 40-95° C and then dried the obtained solid under high vacuum at 40-95° C for 12 hrs to afford crystalline form of Epirubicin hydrochloride (0.65 to 0.90g, Chromatographic purity Not Less Than 98%).
The XRPD pattern as obtained for the solid is depicted in the accompanying Figure.l of this specification.
Example 2 Preparation of crystalline form 'SBL-2' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in n-propanol (100ml) at room temperature was heated to 40-95° C for 10-15 minutes. Then the solvent was removed completely under vacuum at 40-95° C. To the obtained solid, n-propanol (100ml) was added again at 40-95° C and distilled out completely under vacuum at 40-95° C. After repeating the process once again the obtained solid was then dried under high vacuum at 40-95° C for 12 hrs to afford (0.65 to 0.90g, chromatographic purity Not Less Than 98%) of crystalline form of Epirubicin hydrochloride.
The XRPD pattern as obtained for the solid is depicted in the accompanying Figure.2 of this specification.

Example 3. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (Ig) in n-butanol (100ml) at room temperature was heated to 40-95° C for 10-15 minutes. Distill out the solvent completely under vacuum at 40-95° C. To the obtained solid was added again n-butanol (100ml) at 40-95° C and distilled out the solvent completely under vacuum at 40-95° C repeat this process once again and then dried the obtained solid under high vacuum at 40-95° C for 12 hrs to afford crystalline form of Epirubicin hydrochloride (0.65 to 0.90g, chromatographic purity 99.73%).
The XRPD pattern as obtained for the solid is depicted in the accompanying Figure.3 of this
specification.
Drift Spectra as obtained for the solid is depicted in Figure. 4 of this specification
DSC graph as obtained for the solid is depicted in Figure. 5 of this specification
Impurity Profile of the obtained polymorph

Impurity Aglycone Doxorubicin Dihydro Daunomycin Epi-Dauno -mycin Dimer
% 0.08 0.10 ND ND ND 0.09
Example 4. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
Charged amorphous Epirubicin hydrochloride (2g) and methylenedichloride (200ml) in a round bottom flask at 25±2° C. The resulting slurry was refluxed after which n-butanol (80ml) was added. The obtained solution was filtered and stirred at 20± 2° C for 12 hrs. The precipitated solid was filtered, washed with methylene chloride and finally dried at 40-50° C under high vacuum to give 1.2g (60%w/w) of title compound.
Example 5. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in dichloromethane (100ml) at room temperature was heated to 35-40° C for 10-15 minutes. Then n-butanol (40ml) was added slowly at 35-40° C temperature. The contents were then cooled to 20-25° C naturally and seeded with previously prepared crystalline Epirubicin hydrochloride and stirred at 20-25° C for 15 hours. The crystallized solid was then filtered, washed with 10ml of methylene chloride and dried at 40°-45° C under vacuum for 15 hrs to afford crystalline form of Epirubicin hydrochloride (0.80g, 80%).

Example 6. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in methylene chloride (100ml) at room temperature was heated to 35-40° C for 10-15 minutes. Then n-butanol (40ml) was added slowly at 35-40° C temperature. The contents were then partially concentrated at 30-35° C under vacuum and stirred at 20-25° C for 15 hours. The crystallized solid was then filtered, washed with 10ml of methylene chloride and dried at 40°-45° C under vacuum for 15 hrs to afford crystalline form of Epirubicin hydrochloride (0.80g, 80%).
Example 7. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in n-butanol (150ml) was heated to 90-92° C for 10-15 minutes to get clear solution. Then the solvent was distilled out completely under vacuum at 90-92° C. Then Diisopropyl ether (50ml) was added and the contents stirred at 20-25° C for 2 hours. The solid was then filtered, washed with 10ml of fresh Diisopropyl ether and dried at 60° C under vacuum for 24 hrs to afford crystalline form of Epirubicin hydrochloride (0.90g, 90%).
Example 8. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (2g) in n-propanol (100ml) was heated to 90-92° C for 10-15 minutes. Then the solvent was distilled out completely under vacuum at 90-92° C. Then Diisopropyl ether (50ml) was added and the contents stirred at 20-25° C for 2 hours. The solid was then filtered, washed with 10ml of fresh Diisopropyl ether and dried at 50° C under vacuum for 24 hrs to afford crystalline form of Epirubicin hydrochloride (0.90g, 90%).
Example 9. Preparation of crystalline form 'SBL-3' of Epirubicin hydrochloride
A suspension of amorphous form of Epirubicin hydrochloride (lg) in n-propanol (110ml) was heated to 90-92° C for 10-15 minutes. Then n-propanol was distilled out completely under vacuum at 90-92° C. Then ethyl acetate (50ml) was added and the contents stirred at 20-25° C for 2 hours. The solid was then filtered, washed with 10ml of ethyl acetate and dried at 60° C under vacuum for 24 hrs to afford crystalline form of Epirubicin hydrochloride (0.90gs 90%).

We Claim:
1. A novel crystalline form of Epirubicin hydrochloride 'SBL-3' having a powder X-ray diffraction pattern having average values of diffraction angle (20) and relative intensity as given in the following table 2.
Table 2

•Diffraction angle (2θ) Relative intensity (%)
5.03 100.0
7.42 28.11
11.98 6.63
15.99 13.89
16.47 24.85
18.77 6.75
19.38 18.28
19.95 9.65
20.95 6.93
21.99 49.82
22.50 17.12
26.24 19.29
2. A novel crystalline form of Epirubicin hydrochloride as claimed in claim 1, which is obtained by crystallization or precipitation or swapping from a suitable single or mixture of one or more water miscible or water immiscible solvent at suitable temperature.
3. A process for preparing novel crystalline form of Epirubicin hydrochloride as claimed in claim 1, wherein the process comprises the steps of:
(i) dissolving Epirubicin hydrochloride in a single or mixture of suitable water
miscible or immiscible solvent at suitable temperature, and (ii) concentrating the solution at a suitable temperature to furnish crystalline
Epirubicin hydrochloride, or optionally (iii) isolating the solid via filtration by either allowing the product to crystallize gradually from solution or by precipitating the solid by adding a suitable anti solvent to obtain crystalline Epirubicin hydrochloride.

4. The process as claimed in claim 3, wherein the suitable water miscible or immiscible solvent for dissolution is chosen from C-l to C-8 linear or branched alcohols, halogenated solvents, ethereal solvents, esters, either alone or in combination.
5. The process as claimed in claim 4, wherein the alcohol is chosen from methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol or a mixture thereof.
6. The process as claimed in claim 4, wherein the halogenated solvent is chosen from chloroform, dichloromethane, ethylene dichloride or a mixture thereof.
7. The process as claimed in any of the preceding claims 3 to 6, wherein the dissolution is carried out at a temperature of 40-90°C.
8. The process as claimed in any of the preceding claims 3 to 7, wherein concentrating the solution is carried out at a temperature of 40-90°C.
9. The process as claimed in any of the preceding claims 3 to 7, wherein the antisolvent for precipitation is chosen from halogenated solvents, ethereal solvents, esters, or a mixture thereof.
10. A novel crystalline form of Epirubicin hydrochloride obtained by the process claimed in any of the preceding claims 3 to 9.