FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENT RULES, 2003
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)
PHARMACEUTICAL COMPOSITIONS
SUN PHARMACEUTICAL INDUSTRIES LTD.
A company incorporated under the laws of India having their office at ACME PLAZA, ANDHERI-KURLA ROAD, ANDHERI (E), MUMBAI-400059, MAHARASHTRA, INDIA
The following specification describes the invention

PHARMACEUTICAL COMPOSITIONS
The present invention relates to a process for the preparation of a lyophilized form of a water insoluble drug and pharmaceutical compositions comprising such lyophilized form of the drug
BACKGROUND OF THE INVENTION
Parenteral preparations of water insoluble drugs are a difficult task in the pharmaceutical art. Solubilization of water insoluble drugs, using excipients that are generally regarded as safe for parenteral administration, is a complex issue, especially since conventional means of improving solubility may not always be suitable. This is more of a problem for drugs that need to be provided in the form of dosage forms for reconstitution because of stability problems associated with solution forms of the drug. Reconstitution of the drug has to be afforded in the smallest possible time and with minimal efforts, for ease of administration. The solution formed upon reconstitution should be clear, particulate-free, physically and chemically stable and should be safe and efficacious. Meeting these goals is a challenge to the formulator.
Various techniques have been used to improve solubility of water insoluble drugs. For example, the most common technique is that of size reduction of the drug to increase surface area available for interaction with the liquid medium. Size reduction may be carried out using conventional processes such as milling, grinding (with or without a liquid vehicle), precipitation into a non-solvent, and the like. However, these milled particles usually tend to agglomerate over a period of time, thereby forming aggregates that are difficult to dissolve or disperse. This problem has been taken care of by adsorbing a surface stabilizer on the surface of the comminuted drug, immediately after its size is reduced, or carrying out particle size reduction in the presence of a suitable surface stabilizer. This ensures that the particles do not agglomerate into larger aggregates. Typical examples of such techniques are disclosed in United States patents 4,107,288, 4,880,623, 5,202,129, 4,329,332, 5,560,932, 5,662,883, 5,510,118 and others. However, the use of surface stabilizer may not be suitable for parenteral preparations. Also, the process is tedious and time-consuming. Although the solubility of the drug may improve upon size reduction, the time required to solubilize or reconstitute the drug, may still be an issue.
Further, it has been observed with some drugs that size reduction using conventional techniques causes the crystal lattice to fracture in a manner such that upon contact with a solvent or water
2

during formulation of the drug, stability issues such as development of unwanted coloration, chemical degradation, may arise.
United States Application no 2005/0152979A1 claims a lyophilized composition comprising a hydrophobic biologically active agent; a polymer that renders said hydrophobic active agent soluble in an aqueous solution, and a reconstitution enhancing agent, wherein time of reconstitution of said composition in an aqueous solution is less than that for said composition absent said enhancing agent. The compositions are prepared by solubilizing the hydrophobic active agent, the polymer and one or more reconstitution enhancing agents in purified water and lyophilizing the solution to obtain the finished product. This lyophilized product was found to reconstitute in less than 60 seconds in purified water, with the reconstitution enhancing agent being responsible for the fast reconstitution.
Ni et al in International Journal of Pharmaceutics, 226 (2001), 39-46 disclose intravenous injection of an antitumor drug, SarCNU, wherein the SarCNU is lyophilized in neat t-butanol to obtain a uniform cake of needle-shaped crystals. The article discloses that only 0.001% or 10 ppm of the t-butanol is left in the lyophilized cake. However, our repeated experiments of lyophilization of other drugs like docetaxel, paclitaxel and cyclosporin with t-butanol using the freeze drying cycle detailed in Ni et al, resulted in larger amounts of residual solvent, which would be harmful in a parenteral composition.
There is therefore a need to provide an easy process and a convenient means for improving solubility of water insoluble drugs, while not compromising on the stability of the drug.
OBJECTS OF THE INVENTION
The present invention relates to a process for the preparation of a lyophilized form of a water insoluble drug and pharmaceutical compositions comprising such lyophilized form of the drug
it as another object of the present invention to provide a lyophilized form of a water insoluble drug prepared by the process of the invention.
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It as yet another object of the present invention to provide a sterile composition comprising the lyophilized form of a water insoluble drug, prepared by the process of the invention.
It as yet another object of the present invention to provide a kit comprising a sterile composition comprising the lyophilized form of a water insoluble drug, prepared by the process of the present invention in a first container, and a sterile liquid vehicle consisting essentially of a solubilizer and a solvent in a second container.
SUMMARY OF THE INVENTION
The present invention may be summarized as follows:
A) A process for the preparation of a lyophilized form of a water insoluble drug said process
comprising
a. mixing the water insoluble drug with a sufficient quantity of ethanol to dissolve said
drug,
b.sterilizing the solution
c. precipitating the drug by adding sufficient quantity of sterile water, and d.subjecting the sterile suspension so obtained to lyophilization.
B) A process as in A above, wherein the water insoluble drug is selected from the group consisting of docetaxel, paclitaxel, cyclosporine and flunisolide.
C) A process as in B above, wherein the lyophilized form is substantially free of residual ethanol solvent.
D) A process as in B above, wherein the lyophilized form contains less than 3,000 ppm of residual ethanol solvent.
E) A process as in A above, wherein the suspension to be lyophilized is filled into unit dose
containers and lyophilized.
F) A process as in A above, wherein the lyophilized form of the water insoluble drug is dry
powder filled into unit dose containers.
G) A process as in A wherein the drug is docetaxel, the concentration of docetaxel in
ethanol is from about 90mg/ml to about 98mg/ml, the ratio of ethanol to water is about
1:5 and the precipitation is carried out at room temperature.
H) A lyophilized form of a water insoluble drug prepared by the process as in A above.
1) A sterile composition comprising the lyophilized form of a water insoluble drug as in H
above. .
J) A kit comprising -
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a. a sterile composition as in I above in a first container, and
b.a sterile liquid vehicle consisting essentially of a solubilizer and a solvent selected
from organic compounds having a hydroxyl group and molecular weight less than
200, in a second container.
K.) A sterile composition prepared by adding a sterile liquid vehicle consisting essentially of
a solubilizer and a solvent selected from organic compounds having a hydroxyl group
and molecular weight less than 200, to the lyophilized form of a water insoluble drug as
in H above.
L) A sterile composition as in K above, wherein the solubilizer is polyoxyethylene 20
sorbitan monooleate and the solvent is ethanol.
M) An infusion solution prepared by a process comprising diluting the sterile composition as
in J above with an aqueous infusion vehicle.
N) Lyophilized docetaxel.
O) Lyophilized docetaxel as in N above having less than 5000ppm of impurities of organic
solvent.
P) Lyophilized docetaxel as in N above having less than 0.5% of total impurities after storage for 2 months at 25°C, 60% relative humidity.
DETAILED DESCRIPTION OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention.
Figure 1: XRD of the lyophilized form of docetaxel obtained in Example 2, after lyophilization.
Figure 2: XRD of the lyophilized form of docetaxel obtained in Example 2, after storage at 25+/-2°C, % RH: 60+/-5% for 3 months.
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The present invention provides a process for the preparation of a lyophilized form of a water insoluble drug, said process comprising
a. mixing the water insoluble drug with a sufficient quantity of ethanol to dissolve said
drug,
b. sterilizing the solution
c. precipitating the drug by adding sufficient quantity of sterile water, and
d. subjecting the sterile suspension so obtained to lyophilization.
The term "water insoluble drug" as used herein includes drugs that dissolve with difficulty in a sterile liquid vehicle suitable for parenteral administration. Examples of such drugs include, but are not limited to taxoids such as docetaxel and paclitaxel, steroids such as flunisolide, cyclosporine, and their pharmaceutically acceptable salts, derivatives, analogs and isomers. For example, a water insoluble drug may be a drug which dissolves with difficulty when 20 mg of the drug is added to a liquid vehicle consisting of 520 mg of polyoxyethylene 20 sorbitan monooleate and 0.2 ml of ethanol.
A preferred drug for the present invention is docetaxel. Docetaxel is an antineoplastic agent belonging to the taxoid family. It is prepared by semisynthesis beginning with a precursor extracted from the renewable needle biomass of yew plants. The chemical name for docetaxel is (2R,3S)-N-carboxy-3-phenylisoserine,N-tert-butyl ester, 13-ester with 5/3-20-epoxy-l,2α,4,7β,10β,13α-hexahydroxytax-ll-en-9-one 4-acetate 2-benzoate, Docetaxel is marketed in the United States of America as TAXOTERE® injection concentrate. TAXOTERE (docetaxel) Injection Concentrate is a clear yellow to brownish-yellow viscous solution. TAXOTERE is sterile, non-pyrogenic, and is available in single-dose vials containing 20 mg (0.5 mL) or 80 mg (2 mL) docetaxel (anhydrous). Each mL contains 40 mg docetaxel (anhydrous) and 1040 mg polysorbate 80. TAXOTERE Injection Concentrate requires dilution prior to use. TAXOTERE as a single agent is indicated for the treatment of patients with locally advanced or metastatic non-small cell lung cancer after failure of prior platinum-based chemotherapy. TAXOTERE in combination with cisplatin is indicated for the treatment of patients with unresectable, locally advanced or metastatic non-small cell lung cancer who have not previously received chemotherapy for this condition. TAXOTERE in combination with prednisone is indicated for the treatment of patients with androgen independent (hormone refractory) metastatic prostate cancer. TAXOTERE in combination with cisplatin and fluorouracil is indicated for the treatment of patients with advanced gastric adenocarcinoma, including adenocarcinoma of the gastroesophageal junction, who have not received prior chemotherapy for advanced disease.
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TAXOTERE in combination with cisplatin and fluorouracil is indicated for the induction treatment of patients with inoperable locally advanced squamous cell carcinoma of the head and neck
Paclitaxel is a natural product with antitumor activity. Paclitaxel is obtained via a semisynthetic process from Taxus baccata. The chemical name for paclitaxel is 5beta,20-epoxy-l,2alpha,4,7beta,10beta,13alpha- hexahydroxytax-ll-en-9-one 4,10-diacetate 2-benzoate 13-ester with (2 R, 3 S )- N- benzoyl-3-phenylisoserine. It is marketed in the United Sates of America as TAXOL Injection. TAXOL is supplied as a nonaqueous solution intended for dilution with a suitable parenteral fluid prior to intravenous infusion. TAXOL is indicated as first-line and subsequent therapy for the treatment of advanced carcinoma of the ovary. As first-line therapy, TAXOL is indicated in combination with cisplatin. TAXOL is indicated for the adjuvant treatment of node-positive breast cancer administered sequentially to standard doxorubicin-containing combination chemotherapy. TAXOL is indicated for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within 6 months of adjuvant chemotherapy. TAXOL, in combination with cisplatin, is indicated for the first-line treatment of non-small cell lung cancer in patients who are not candidates for potentially curative surgery and/or radiation therapy. TAXOL is indicated for the second-line treatment of AIDS-related Kaposi's sarcoma.
Cyclosporine is a cyclic polypeptide immunosuppressant agent consisting of 11 amino acids. It is produced as a metabolite by the fungus species Beauveria nivea. Chemically, cyclosporine is designated as [R-[R*,R*-(E)]]-cyclic(L-alanyl-D-alanyl-N-methyl-L-leucyl-N-methyl-L-leucyl-N-methyl-L-valyl-3-hydroxy-N,4-dimethyl-L-2-amino-6-octenoyl-L-α;-amino-butyryl-Nmethylglycyl-N-methyl-L-leucyl-L-valyl-N-methyl-Lleucyl). It is available in the United States of America as Sandimmune® Injection. Sandimmune® Injection is available in a 5 mL sterile ampul for I.V. administration. Sandimmune® (cyclosporine) is indicated for the prophylaxis of organ rejection in kidney, liver, and heart allogeneic transplants.
The term "dissolve(s) with difficulty" as used herein means that the water insoluble drug requires more than 2 minutes to form a clear solution (i.e. presence of no visible particles) when 20mg of the drug is mixed with a sterile liquid vehicle consisting essentially of 520mg of Polysorbate 80 and 0.2ml of ethanol, such as, for example, when mixed in a vial and the vial agitated manually,
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or when mixed in a vial and the vial agitated in a rotating bottle apparatus at 50rpm, or when mixed in a vial and the vial agitated in a multipulse shaker at 50 rpm.
The present invention provides a process for the preparation of a lyophilized form of a water insoluble drug in order to provide means for improving solubility of water insoluble drugs by converting the drug to a physical form that is suitable for dissolving and readily forming a clear solution in the desired liquid vehicle suitable for parenteral administration. This physical form of the drug (also referred to herein as lyophilized form of the drug) is capable of dissolving in the liquid vehicle in less than two minutes with minimal efforts. For example, upon conversion to the suitable physical form, the drug dissolves in the liquid vehicle immediately upon addition of the liquid vehicle, or with minimum agitation of the container by the professional personnel reconstituting the drug composition, with a sterile liquid vehicle suitable for parenteral administration, and/or with an aqueous infusion vehicle. Further, the use of the suitable physical form of the drug ensures that the drug stays in solution in the liquid vehicle for at least 2 hours after reconstitution. Preferably, the drug stays in solution for about 8 hours after reconstitution, when stored under normal conditions of storage, such as ambient room temperature.
The term "sterile liquid vehicle suitable for parenteral administration" (this term has been used interchangeably with "sterile liquid vehicle" and "liquid vehicle") as used herein means a vehicle that is capable of dissolving the lyophilized form of the water insoluble drug, and which is suitable for parenteral administration, without causing any adverse events to the patient. The sterile liquid vehicle consists essentially of a solubilizer and a solvent selected from organic compounds having a hydroxyl group and molecular weight less than 200. Examples of liquid vehicles suitable for use in the sterile liquid vehicle of the present invention include, but are not limited to, alcohols like ethanol, benzyl alcohol, isopropyl alcohol, and the like, propylene glycol, polyethylene glycol, and the like and mixtures thereof. The solubilizer suitable for use in the sterile liquid vehicle include, but are not limited, to polyoxyethylene sorbitan fatty acid esters, polyoxyethylene castor oil derivatives, fatty acid-polyethylene glycol esters, vitamin E tocopherol propylene glycol succinate (Vitamin E TPGS), sucrose-fatty acid esters and the like and mixtures thereof.
Polyoxyethylene sorbitan fatty acid esters that can be used as solubilizer in the liquid vehicle of the present invention may be selected from polyoxyethylene 20 sorbitan monolaurate (Polysorbate 20), polyoxyethylene 20 sorbitan monopalmitate (Polysorbate 40), polyoxyethylene
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20 sorbitan monooleate (Polysorbate 80) and mixtures thereof. These polyoxyethylene sorbitan fatty acid esters (polysorbates) are a series of partial fatty acid esters of sorbitol and its anhydrides copolymerized with approximately 20 moles of ethylene oxide for each mole of sorbitol and its anhydrides. Preferably, the polysorbate of choice is polysorbate 80 having a saponification value in the range of 45-55, moisture content of 3% or less, hydroxyl value of 65-80 and an acid value of 2% or less. It may be used in an amount ranging from about 250mg per ml of the liquid vehicle to about lOOOmg per ml of the liquid vehicle.
Polyoxyethylene castor oil derivatives are a series of materials obtained by reacting varying amounts of ethylene oxide with either castor oil or hydrogenated castor oil, thereby forming a complex mixture of hydrophobic and hydrophilic components. They mainly contain ricinoleyl glycerol ethoxylated with 30-50 molecules of ethylene oxide. Commercially available grade of polyoxyl 40 hydrogenated castor oil, Cremophor RH 40, is preferred as the liquid vehicle, having a moisture content of 2% or less, saponification value of 45-69, iodine value of 2.0 or less and a hydroxyl value of 60-80.
The sterile liquid vehicle is used in an amount sufficient to dissolve the lyophilized form of the water insoluble drug, and in an amount that is safe and non-toxic for parenteral administration. Preferably, the liquid vehicle used, and the amount in which it is used, is selected such that a stable composition is obtained, i.e. a composition that does not precipitate the drug for at least 2 hours after the liquid vehicle has been added to the drug. In one embodiment of the present invention, 520mg of polysorbate 80 is used in combination with 0.2ml of ethanol as the liquid vehicle. The sterile liquid vehicle of the present invention may be provided in a separate container. The vehicle may be filled into unit dose containers and subjected to sterilization. Sterilization may be carried out in any of the conventional methods known in the art, such as, steam sterilization, dry heat sterilization, radiation sterilization, sterile filtration, or any other means of sterilization that is suitable for the particular liquid vehicle being used.
In the process of the invention, the water insoluble drug is converted to a physical form suitable for dissolving and readily forming a clear solution in the sterile liquid vehicle, by first mixing the water insoluble drug with a sufficient quantity of ethanol to dissolve the drug and then sterilizing the resultant solution. Sterilization may be typically done by membrane filtration of the solution. Alternatively, it may be sterilized by any other conventional means of sterilization as may be suitable for the sterile liquid vehicle. A sufficient quantity of sterile water, or other sterile non-
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solvent, is then added to precipitate the drug out of the solution. The sterile suspension so obtained is subjected to lyophilization. The lyophilized product obtained is suitable for dissolving and readily forming a clear solution in the sterile liquid vehicle.
Lyophilization or freeze-drying may be performed using commercial freeze-dryers, such as are available from a variety of sources, using manufacturer recommended settings. Typically, the product is freeze-dried so that the lyophilized product contains less than about 3000 ppm of the solvent. In processes where an aqueous suspension is subjected to lyophilization, the product is freeze-dried so that less than about 1.5% w/v moisture is present. In one example, the product is loaded at about 5° C, frozen to about -40° C and held at -40° C for about seven to about eight hours; the frozen solution is then thermally treated by raising the shelf temperature to -20° C to -25° C, and holding at that temperature for 2 to 8 hours. Thereafter, the condenser can be started, the vacuum adjusted and the shelf temperature raised to +25° C. Optionally, when the product temperature reaches +25° C, the product is subjected to secondary drying. Suitably, the lyophilization process results in a product having residual solvent in an amount of less than 2% by weight of the final weight of solids in the lyophilized product. In addition or alternatively to the second step, other processing techniques can be used to further reduce the residual solvent in the resulting lyophilized material. Such processing techniques include nitrogen sweeps, among other methods.
The lyophilization may be carried out in bulk or in unit dose containers. For example, the sterile suspension of the water insoluble drug obtained upon addition of sterile water may be subjected to bulk lyophilization, followed by aseptic filling of the required amount of the lyophilized product into sterile unit dose containers. This is typically referred to as dry powder filling. The cake obtained on bulk lyophilization may be subjected to mechanical sieving under aseptic conditions, prior to filling into unit dose containers, so as to break any agglomerates and facilitate easy filling of the required amount of the product into sterile containers. Alternatively, the suspension of the water insoluble drug may be filled into unit dose containers, with each container containing an equal amount of the suspension. These individual containers are may then be subjected to lyophilization, so that the lyophilized product is obtained in the unit dose containers. In one embodiment of the present invention, the sterile solution of the water insoluble drug in ethanol is filled aseptically into sterile unit dose containers and the required quantity of sterile water is added to each container to precipitate the drug, i.e. to form a suspension. The unit dose containers containing the sterile suspension are then lyophilized. In the process of the
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invention, the lyophilization is carried out by subjecting the sterile suspension of the water-insoluble drug to lyophilization, such that the lyophilized form contains less than about 3000 ppm of the residual solvent. In a preferred embodiment of the invention, the lyophilization is carried out by subjecting the sterile suspension of the water-insoluble drug to lyophilization, such that the lyophilized form contains less than about 3000 ppm of ethanol.
In one embodiment of the present invention, a kit is provided which comprises-
• a sterile composition comprising the lyophilized form of a water insoluble drug prepared by the process as described herein in a first container, and
• a sterile liquid vehicle consisting essentially of a solubilizer and a solvent selected from organic compounds having a hydroxyl group and molecular weight less than 200, in a second container.
The sterile composition comprising the lyophilized form of a water insoluble drug in a first container is dissolved readily upon addition of the sterile liquid vehicle provided in the second container. Typically, the lyophilized form of the water insoluble drug obtained by the process of the present invention dissolves in less than 3 minutes, upon addition of the sterile liquid vehicle. Preferably, the lyophilized form dissolves in less than 2 minutes.
In one embodiment of the present invention, an infusion solution is provided by diluting the sterile composition i.e. the lyophilized form of a water insoluble drug dissolved in the sterile liquid vehicle, with an aqueous infusion vehicle. Examples of such aqueous infusion vehicles include, but are not limited to, 5% dextrose solution, 0.9% physiological saline, sterile water for injection, and the like, conventionally used in hospitals for administration. The choice of the infusion that may be used for diluting the sterile composition of the invention depends on the compatibility of the drug with the infusion solution to be used.
In yet another embodiment of the present invention, pharmaceutical excipients that improve stability of the pharmaceutical composition may be added to the solution of the drug in the ethanol, prior to lyophilization or solvent removal, in order to prevent any chemical degradation of the drug. For example, antioxidants, chelating agents, tonicity agents, buffers, pH-adjusting agents, cryoprotectants, bulking agents that aid in lyophilization, diluents and various other
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pharmaceutical agents conventionally used in parenteral formulations may be used in amounts conventional to the pharmaceutical art.
In a preferred embodiment of the present invention, a taxane derivative is used as the water insoluble drug to obtain the pharmaceutical composition of the present invention. Particularly, docetaxel is used as the preferred taxane derivative to provide lyophilized docetaxel. Prior art parenteral formulations of docetaxel were obtained by dissolving docetaxel in a mixture of Cremophor and ethanol (as disclosed in example 1 of US 4,814,470). However, the solubility of docetaxel is so poor, that a large amount of Cremophor and ethanol, i.e. 50% by volume of Cremophor and 50% by volume of ethanol, is required to obtain a solution formulation. The high quantities of Cremophor were found to cause anaphylactic reactions in patients, while the high amount of ethanol caused alcoholism (see Rowinsky, Lorraine, Cazenave and Donehower, Journal of the National Cancer Institute, vol. 82, No. 15, pages 1247 to 1259). In order to avoid these problems associated with Cremophor and ethanol, a new formulation was prepared by Rhone-Poulenc Rorer (as described in US 5,438,072), which was essentially free of ethanol, and which replaced Cremophor with another surfactant selected from polysorbates, ethylene oxide esters-ethers and fatty acids glycerides. The commercial product, Taxotere©, includes Polysorbate 80 as the surfactant. The product is available in the form of a kit - a first vial containing a solution of docetaxel in Polysorbate 80, and a second vial containing water with 13% ethanol, as the diluent. The present invention provides, in a preferred embodiment, a stable pharmaceutical composition of docetaxel (see examples 1 and 2 below), which is easy to reconstitute prior to administration, and which overcomes the disadvantages of the prior art, such as alcoholism and anaphylactic reactions.
The examples that follow do not limit the scope of the present invention and are merely used as illustrations.
Comparative Example 1
Docetaxel (20 mg) was dissolved in tertiary Butanol (1 ml) at a controlled temperature of 25±2°C. The solution thus obtained was then sterile filtered, filled in sterile vials and lyophilized to form a white cake. The lyophilization cycle detailed in Table 1 below was used.
Table 1
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Temp °C Time Pressure Time Stage Total time
HH MM ss No. % HH .MM SS HH MM SS"~
+5 01 00 00 Freezing 07 30 00
-40 01 30 ; 00
-40 05 00 00 cycle
-40 01 00 00 Preparation 01 00 00
-40 00 10 00 1 40 00 10 00 Primary 42 50 oo~i
-20 00 40 00 2 36 10 40 00 Drying
-20 10 00 00 3 30 32 00 00
0 03 20 00
0 05 00 00 __
25 04 10 00
25 20 00 00
25 00 00 01 Secondary 00 00 01
i drying
Extend Secondary drying at +25deg. Temp. and 30% pressure, until moisture content is achieved i below 1% & t-butanol content below 50000ppm.
The lyophilized docetaxel thus obtained had a residual solvent (t-butanol) content of about 15000ppm and it was difficult to reduce this to less than 5000ppm. Such high amounts of residual solvent would obviously be unacceptable for use.
Example 1
A pharmaceutical composition according to the present invention was prepared as mentioned below to provide a final dosage form comprising 20mg of lyophilized docetaxel per vial. Docetaxel (97.6 mg) was dissolved in 1ml of ethanol, i.e. dehydrated alcohol with stirring at medium speed. The solution thus obtained was sterile filtered through membrane filter, and 0.25ml of the filtered solution was filled into a sterile vial. To this was added 1.25ml of water for injection, and the suspension thus obtained was lyophilized by the lyophilization cycle detailed in Table 2 below. Lyophilization was carried out till water content was below 1.55%, and ethanol content was below 3000 ppm. A porous cake was obtained upon lyophilization.
Table 2

Temp °C Time Pressure Time Stage Total time
HH MM SS No. bar HH MM SS HH M M SS
+5 00 30 00 Freezing cycle 06 00 00
-40 01 30 00
-40 04 00 00
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-40 01 00 00 Preparation for drying 01 00 00
-40 30 00 00 1 933 10 00 00 Primary DryingSecondary drying 123 50 00
-35 00 50 00 2 700 10 00 00
-35 10 00 00 3 550 12 30 00
-30 00 , 50 00 4 420 12 10 00
-30 23 00 00 5 300 10 00 00
-25 00 50 00 6 266 25 00 00
-25 10 00 00 7 200 08 20 00
00 04 10 00 8 133 05 00 00
00 03 20 00 9 66 30 00 00
30 05 00 00
30 35 00 00 00 00 01
Example 2
A pharmaceutical composition according to the present invention was prepared as mentioned below to provide a final dosage form comprising 80mg of lyophilized docetaxel per vial. Docetaxel (94.4 mg) was dissolved in 1ml of ethanol, i.e. dehydrated alcohol with stirring at medium speed. The solution thus obtained was sterile filtered through membrane filter, and 1.0 ml of the filtered solution was filled into a sterile vial. To this was added 5.0 ml of water for injection, and the suspension thus obtained was lyophilized by the lyophilization cycle detailed in Table 3 below. Lyophilization was carried out till water content was below 1.55%, and ethanol content was below 3000 ppm. A porous cake was obtained upon lyophilization.
Table 3

Temp °C Time Pressure Time Stage Total time
HH MM SS No. bar HH MM SS HH M M SS
+5 00 30 00 Freezing cycle 06 00 00
-40 01 30 00
-40 04 00 00
-40 01 00 00 Preparation for drying 01 00 00
-40 30 00 00 1 933 10 00 00 Primary Drying 123 50 00
-35 00 50 00 2 700 10 00 00
-35 10 00 00 3 550 12 30 00
-30 00 50 00 4 420 12 10 00
-30 23 00 00 5 300 10 00 00
-25 00 50 00 6 266 25 00 00
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-25 10 00 00 7 200 08 20 00 Secondary drying
00 04 10 00 8 133 05 00 00
00 03 20 00 9 66 30 00 00
. 30 05 00 00
30 35 00 00 00 00 01
Secondary drying extended until water content is achieved at below 1.5% & ethanol content below 3000ppm.
The composition was provided in the form of a kit comprising a first vial containing 80mg docetaxel, as obtained by the lyophilization cycle described above, and a second vial containing a mixture of 64.6% w/w Polysorbate 80 and 35.4% w/w of ethanol. The porous docetaxel cake of the first vial is dissolved in the mixture of polysorbate 80 and ethanol (of the second vial) in less than 90 seconds to obtain a clear solution that can be used as the stock solution to prepare further dilutions, as the need may be.
Example 3
A comparative solubility study was performed using lyophilized form of docetaxel, obtained as in Example 1 above and a non-lyophilized form of docetaxel. to check the time taken for complete solubilization in liquid vehicle consisting of polysorbate 80 and ethanol. The experiment was carried out at controlled room temperature (25±2°C) using bottle rotating apparatus and multipulse shaker. The time taken for complete solubilization (i.e., formation of a clear solution with presence of no visible particles) of docetaxel was noted and is given in Table 4 below. Experimental Details:
(a) Bottle Rotating Apparatus : 20 mg of Docetaxel was taken in a 5ml vial. To this, 0.7 ml of liquid vehicle was added. The vial was then kept in the bottle rotating apparatus and rotated at 50 RPM. Continuous monitoring was done to check the solubilization of the drug.
(b) Multipulse Shaker Apparatus: 20 mg of Docetaxel was taken in a test tube with stopper. To this, 0.7 ml of liquid vehicle was added. The test tube was then kept in a multipulse shaker and rotated at 50 RPM. Continuous monitoring was done to check the solubilization of the drug.
Table 4

Description Time taken for complete solubilization
Bottle Rotating Apparatus Multipulse Shaker
Docetaxel (non- 10.67 ± 1.53 mins 9 ± 2 minutes
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lyophilized)
Docetaxel Less than 2 mins Less than 2 min
(Lyophilized, as in
Example 1)
It can be observed from the above study that the time taken for complete solubilization of lyophilized form of Docetaxel is significantly lesser than the non-lyophilized form of Docetaxel.
Example 4
Pharmaceutical compositions according to the present invention containing 80mg/vial of docetaxel prepared as in Example 2 above, and were packed in vials and stored at 25+/-2°C, 60+/-5% relative humidity for a period up to three months. The samples were analyzed using high performance liquid chromatography (HPLC). The parameters used in the analysis are given below. The percent total impurities and the assay results are summarized in Table 5 below.
For assay/content of docetaxel:
Column: YMC-Pack ODS-AQ (150 mm x 4.6 mm), 3 u. (YMC Corporation, JAPAN)
Flow rate: 1.0 ml/min
Column temperature: 40°C
Detection: UV at 230 nm
Injection volume: 20/il
Retention time: about 17 minutes
Run time: about 35 min
Mobile Phase: Water and acetonitrile mixed in the ratio of 550 ml:450 ml.
Diluent: Water and acetonitrile mixed in the ratio of 1:1
Standard preparation: 12.5 mg (11.25-13.75mg) of docetaxel mixed with the diluent to 25 ml,
sonicated, and 5ml of this solution further diluted to 50 ml with diluent.
Test preparation: Five vials of docetaxel for injection constituted with 10ml of diluent separately,
and the contents of all these constituted vials mixed and constituted to 50 ml with the diluent. 5ml
of this constituted solution further diluted to 200 ml with diluent.
For related substances:
Column: Waters Sunfire CI 8, 150 mm x 4.6 mm, 3.5 u (Waters Corporation, USA) Flow rate: 1.2 ml/minute
Column temperature: 40°C
16.

Detection: UV at 230 nm
Injection volume: 10 µl
Run time: 53 minutes
Mobile phase A: Water, filtered through 0.45µ filter paper.
Mobile phase B: Acetonitrile, filtered through 0.4µ filter paper.
Retention time: about 19 minutes
Standard preparation: 5 mg of docetaxel mixed with the diluent to 100 ml, and 2 ml of this
solution further diluted to 100 ml with diluent.
Test preparation: Five vials of docetaxel for injection constituted with 5 ml of diluent separately,
and the contents of all these constituted vials mixed and constituted to 100 ml with the diluent.
Table 5

Storage Condition Time period Assay of docetaxel (%) Total impurities(%)
Initial 98.5 0.246
1 month 95.2 0.237
25+/-2°C, % RH: 60+/-5% 2 month 93.9 0.350
3 month 95.1 0.234
Example 5
The lyophilized form of docetaxel obtained in Example 2 was analyzed by XRD. Figure 1 shows the XRD after lyophilization.
Example 6
The lyophilized form of docetaxel obtained in Example 2 was analyzed by XRD. Figure 2 shows the XRD of the lyophilized form of docetaxel after storage at 25+/-2°C, % RH: 60+/-5% for 3 months.
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While the invention has been described by reference to specific embodiments, this was done for purposes of illustration only and should not be construed to limit the spirit or the scope of the invention.
Dated this 20"' day of April 2007.
DILIP SHANGHVI
CHAIRMAN AND MANAGING DIRECTOR, SUN PHARMACEUTICAL INDUSTRIES LIMITED.
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