FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
LIQUID FORMULATION OF POLYPEPTIDES CONTAINING AN Fc DOMAIN
OF AN IMMUNOGLOBULIN
Intas Biopharmaceuticals Limited
An Indian company having its registered office at:
Plot No.:423/P/A/GIDC
Sarkhej-Bavla Highway
Moraiya, Tal.: Sanand
Ahmedabad-382 210
Gujarat, India
The following specification describes the invention.

FIELD OF THE INVENTION
The present invention relates to an aqueous formulation comprising TNFR:Fc, methods of manufacture of the composition, methods of administration and kits containing the same.
BACKGROUND OF THE INVENTION
Tumour necrosis factor is a polypeptide cytokine involved in inflammation and the acute phase response. TNF-alpha is present in larger quantities in persons with rheumatoid arthritis or Crohn's disease. Direct inhibition of TNF-alpha by the biological agents has produced significant advances in rheumatoid arthritis treatment and has validated the extra-cellular inhibition of this pro-inflammatory cytokine as an effective therapy. One such biological agent is Etanercept.
Etanercept (TNFR:Fc) is a dimeric fusion protein consisting of the extra-cellular ligand-binding portion of the human 75 kilo Dalton (p75) tumor necrosis factor receptor (TNFR) linked to the Fc portion of human IgGl. The Fc component of Etanercept consists of the CH domain, the CH3 domain and hinge region, whereas the CH! domain is absent. It is produced through recombinant DNA technology in a Chinese hamster ovary mammalian cell expression system. It consists of 934 amino acids, and has an apparent molecular weight of approximately 150 kilo Dalton.
Generally, proteins have a very short half-life, and undergo denaturation (such as aggregation, dissociation, and adsorption on the surface of vessels) upon exposure to various factors such as unfavorable temperatures, water-air interface, high-pressure, physical/ mechanical stress, organic solvents and microbial contamination. Consequently, the denatured protein loses intrinsic physicochemical properties and physiological activity. Denaturation of proteins is often irreversible, and therefore proteins, once denatured, may not recover their native properties to the initial state.
In the biopharmaceutical industry, the long term storage of proteins, prepared using recombinant DNA technology in aqueous formulations, is generally a difficult task. To

overcome the stability problem of proteins in aqueous formulations, therapeutic protein products are made more stable via lyophilization (freeze-drying). Lyophilized products are usually accompanied by sterile aqueous media for reconstitution. After reconstitution, the formulations typically have short useful storage lives, even when stored at low temperatures (e.g., 5°C). Example of TNF alpha inhibitors which are available in the market in the lyophilized form are Enbrel and Remicade and both the compositions should be reconstituted before use.
Typical practices to improve polypeptide stability can be addressed by varying the concentration of elements with the formulation, or by adding excipients to modify the formulation.
US55S0856 discloses the stabilization of dried proteins against loss of biological activity in the formulations by adding a reconstitution stabilizer upon rehydration of the dried protein. A kit for producing a formulation by dissolving the dried composition in a solvent containing the reconstitution stabilizer is also described.
US6171586 discloses a stable aqueous pharmaceutical formulation comprising a therapeutically effective amount of an antibody not subjected to prior lyophilization, a buffer maintaining the pH in the range from about 4.5 to about 6.0, a surfactant and a polyol, along with uses for such a formulation.
EP1314437 relates to an invention of stabilized preparations containing an antibody in a glycine buffer and/ or a histidine buffer and also provides processes for preparing a protein-containing stabilized preparation, comprising adjusting the pH with a basic amino acid or a basic amino acid derivative or a salt thereof.
EP1478394 discloses about the invention that relates to an aqueous pharmaceutical composition suitable for long-term storage of polypeptides containing an Fc domain of an immunoglobulin, methods of manufacture, methods of administration and kits containing same.

Thus, it is desirable to provide liquid formulations of TNFR: Fc having enhanced stability under refrigeration and at least moderate stability at normal room temperatures and to avoid the inconvenience and potential for errors from the reconstitution procedure
SUMMARY OF THE INVENTION
The invention provides a novel liquid formulation comprising XNFR:Fc which exhibits
long term stability at 4°C and room temperatures.
In one aspect, the invention provides a formulation consisting of a polypeptide containing
an Fc domain of an immunoglobulin and an aggregation inhibitor, wherein the
aggregation inhibitor is selected from the group consisting of aspartic acid,
phenylalanine, glutamic acid, alanine, histidine and lysine.
In another aspect, the formulation comprises a polypeptide containing an Fc domain of an immunoglobulin, an aggregation inhibitor, buffer, a non-ionic surfactant, polyol, a stabilizer, a tonicity modifier, and a chelating agent.
The buffer system of the novel formulation is selected from the group consisting of sodium phosphate, histidine, potassium phosphate, sodiurn or potassium citrate, maleic acid, ammonium acetate, tris-(hydroxymethyl)-aminormethane acetate and diethanolamine or a combination thereof.
In yet another aspect, the formulation comprises the ionic surfactant selected from the group consisting of a polysorbate-based non-ionic surfactant and a poloxamer-based non-ionic surfactant or a combination thereof.
The polyol of the formulation is further selected from the group consisting of sucrose, trehalose, maltose, mannitol, xylitol, maltitol and sorbitol or a combination thereof. The stabilizer of the formulation is selected from the group consisting of EDTA (ethylenediamine tetraacetic acid), HEDTA (hydroxyethyenediamine triacetic acid), NTA (nitriolotriacetic acid), DTPA (Diethylenetriamine pentaacetate) and citric acid or a combination thereof.
Furthermore, the formulation provides for a tonicity modifier selected from the group consisting of sodium chloride, potassium chloride, sodium sulfate or a combination thereof.

In another aspect, present invention provides for a polypeptide containing an Fc domain of an immunoglobulin selected from the group consisting of monoclonal antibody, fusion protein and TNFR:Fc.
The formulation of the present invention encompasses TNFR:Fc comprising aspartic acid, sodium-potassium phosphate buffer, lysine, sodium chloride, sucrose, polysorbate 20 and disodium ethylene diamine tetra acetic acid wherein TNFR:Fc is present at a concentration of 10 mg/ml to 100 mg/ml.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure la (Non-reducing) & Figure lb (Reducing) shows the comparison of degradation pattern of Etanercept formulations with different aggregation inhibitors kept at 40°C on zero day.
Lane 1: Reference Medicinal Producr
Lane 2: F-l as given in Table 1
Lane 3: F-2 as given in Table 1
Lane 4: F-3 as given in Table 1
Lane 5: F-4 as given in Table 1
Figure 2a (Non-reducing) & Figure 2b (Reducing) shows the comparison of degradation pattern of Etanercept formulations with different aggregation inhibitors kept at 40°C for 1 month.
Lane 1: Reference Medicinal Product
Lane 2: F-l as given in Table 1
Lane 3: F-2 as given in Table 1
Lane 4: F-3 as given in Table 1
Lane 5: F-4 as given in Table 1
Figure 3a (Non-reducing) & Figure 3b (Reducing) shows the comparison of degradation pattern of Etanercept formulations with different aggregation inhibitors kept at 47°C for 16 hours.
Lane I: Reference Medicinal Product
Lane 2: F-3 as given in Table 1

Lane 3: F-l as given in Table 1 Lane 4: Marker
Figure 4 shows the comparison of degradation pattern of Etanercept formulations with different aggregation inhibitors kept at 55°C for 24 hours.
Lane 1: Reference Medicinal Product
Lane 2: F-3 as given in Table 1
Lane 3; F-l as given in Table 1
Lane 4: Marker
Figure 5a (Non-reducing) & Figure 5b (Reducing) shows the comparison of degradation pattern of Etanercept formulations with lysine as stabilizer, kept at 40°C for 7 days.
Lane 1: Reference Medicinal Product
Lane 2: F-5 as given in Table 1
Lane 3: F-3 as given in Table 1
Lane 4: Marker
Figure 6a (Non-reducing) & Figure 6b (Reducing) shows the comparison of degradation pattern of Etanercept formulations kept at 40°C on Zero day for checking the effect of EDTA.
Lane 1: Without EDTA
Lane 2: With EDTA
Lane 3: Marker
Figure 7a (Non-reducing) & Figure 7b (Reducing) shows the comparison of degradation pattern of Etanercept formulations kept at 40°C for 3 days.
Land: Without EDTA
Lane 2: With EDTA
Lane 3: Marker

Figure 8a, Figure 8b and Figure 8c shows the DSC profile of Etanercept formulations with different buffer and their salt.
Figure 9 shows comparative transition midpoints of formulations (F6 to F8).
Figure 10 shows comparative bioactivity of Final formulated bulk and RMP
Figure 11 shows comparative degradation by SE=HPLC in F6, F8 and RMP.
Figure 12 shows comparative HIC profile of F8 and RMP kept at -20°C for 3 months.
Figure 13 shows comparative HIC profile of F8 and RMP kept at 5±3°C °C for 3
months.
Figure 14 shows comparative HIC profile of F8 and RMP kept at 25±2°C °C for 3
months.
Figure 15 shows comparative HIC profile of F8 and RMP kept at 40°C for 3 months.
DESCRIPTION OF THE INVENTION
The present pharmaceutical formulation comprises a purified polypeptide, buffer, aggregation inhibitors, tonicity modifiers, stabilizers, surfactants, chelating agents and optionally with preservative in suitable combinations thereof.
Monoclonal antibodies are used in high concentration for therapeutic use and the high concentration of protein is known to increase aggregation. In one aspect, aggregation inhibitors are required in formulation compositions to keep the product in native state as well as biologically active with enhanced shelf life and storage conditions. There are a few amino acids which act as aggregation inhibitors by increasing surface tension, preferential binding or hydration and preferential interaction.
Aggregation inhibitors reduce a polypeptide's tendency to form aggregates. The amino acids like aspartic acid, phenylalanine, glutamic acid, alanine, histidine and lysine act to reduce aggregation of Fc domain containing polypeptide in a formulation for long periods and are preferred embodiments of the invention.

In another aspect, buffers are required for maintaining pH of the formulation. The buffer system of the present invention comprises phosphate buffer, bicarbonate buffer, succinate buffer, acetate buffer, citrate buffer, amino acids, TRIS buffer, either alone or in suitable combination giving desired pH range from 5,5 to 7,5,
In the present invention, surfactant is used in order to prevent adsorption of TNFR:Fc on the surface of the vial, ampoule, carpoule, cartridge or syringe. Surfactants lower surface tension of a protein solution, thereby, preventing its adsorption or aggregation on to a hydrophobic surface. Preferred surfactants of the present invention include a polysorbate-based non-ionic surfactant and polyoxyethylene copolymer, polyvinylpyrrolidone, either alone or in combination.
In one embodiment, stabilizers used in the present invention are selected from the group that consists of: amino acids such as glycine, alanine, lysine, praline, serine and the like and its salts thereof, either alone or in combination, monosaccharide such as glucose and mannose, and their likes, either alone or in combination, disaccharides such as sucrose, trehalose, and maltose, and their likes, either alone or in combination, sugar alcohols such as mannitol and sorbitol, and their likes, either alone or in combination, and polysaccharides such as dextran , polyethylene glycol and their likes, either alone or in combination.
A tonicity modifier is understood to be a molecule that contributes to the osmolality of a solution. The osmolality of a pharmaceutical composition is preferably regulated in order to maximize the active ingredient's stability and also to minimize discomfort to the patient upon administration. Examples of tonicity modifiers suitable for modifying osmolality include, but are not limited to amino acids (arginine, cysteine, histidine and the like), salts (sodium chloride, potassium chloride, calcium chloride and the like), and/or saccharides (sucrose, glucose, mannitol and their likes).
Etanercept is prone to fragmentation during storage, so some fragmentation inhibitor is required for making optimum formulation composition for etanercept. EDTA known to

have an impact in preventing fragmentation in many of the products such as Interferon, Alemtuzumab, etc is used in the present formulation.
Chelating agents stabilize or prevent the free metal ions to react with protein of interest. Examples of chelating agents that can be used in the present invention includes but not limited to EDTA (ethylenediamine tetraacetic acid), HEDTA (hydroxyethylenediamine triacetic acid), NTA (nitriolotriacetic acid), DTPA (Diethylenetriamine pentaacetate) and citric acid.
Preservative refers to a composition or substance added to a formulation to act as a bacteriostatic agent. A preserved TNFR: Fc containing formulation of the present invention preferably meets statutory or regulatory guidelines for preservative effectiveness to be a commercially viable multi-use product, preferably in humans. Preservatives used in the present invention are selected from the group consisting of phenol, m-cresol, p-cresol, o-cresol, chloro-cresol, alkylparaben (methyl, ethyl, propyl, butyl and the like), benzethonium chloride, sodium dehydroacetate or thiomersal, either alone or in combination thereof. However, in the present invention, the use of preservative is optional and is preferred while designing multi-dose formulations.
The novel, thermostable, aqueous formulation of TNFR: Fc described in the present invention has the following advantages;
1. Involves use of aggregation inhibitor, which prevents the aggregation of the fusion protein during long term storage.
2. Involves use of a stabilizer which prevents unwanted cleavages during long term storage.
3. Provides better stability to the aqueous formulation to maintain its activity for a prolonged period of time to guarantee a reasonable shelf-life.
4. Provides better stability to the aqueous formulation even at elevated temperatures.

The following examples illustrate the pharmaceutical compositions described in the present invention and the means of carrying out the invention to obtain a stable aqueous pharmaceutical formulation of TNFR: Fc. The examples are in no way to be construed as limitations for the scope of the invention.
Example 1
Screening and selection of aggregation inhibitors
Screening of aggregation inhibitors at 40°C
Formulation of Etanercept with different aggregation inhibitors like lysine, aspartic acid, glycine and proline were studied. These formulations also contained other excipients as per details given in Table 1. Samples and RMP were incubated at 40°C for one month and then analyzed by SDS-PAGE. SDS-PAGE was used as an analytical technique which can separate the dissociated and high molecular weight species from native protein based on molecular weight. Due to high propensity to aggregate in case of high concentration of monoclonal antibodies and fusion proteins, non-reducing SDS PAGE was utilized to assess covalent aggregates. As there are many disulphide bonds present in fusion proteins as well as monoclonal antibodies, the fragmentation of proteins was checked under reducing SDS PAGE.
SDS-PAGE gel (Fig. la, lb, 2a & 2b) of different formulations shows the aggregation and fragmentation of Etanercept after one month at 40°C.
Table 1: Identification of aggregation inhibitor

Sr.
No Components Formulation No.

Fl F2 F3 F4
1. Etanercept 50 mg 50 mg 50 mg 50 mg
2. Sucrose 20 mg 20 mg 20 mg 20 mg
3. Phosphate Buffer 25 mM 25 mM 25 mM 25 mM
4. DL-Aspartic acid 20 mM - - -
5. L-Lysine Monohydrate - 20 mM - -
6. Glycine - - 20 mM -
7. Proline - - - 20 mM
8. Sodium Chloride 100 mM 100mM 100 mM 100 mM

9. Polysorbate 20 0.2 mg 0.2 mg 0.2 mg 0.2 mg
10. Disodium EDTA 1 mM 1 mM 1 mM 1mM
F2 and F4 were found to have more degradation in terms of aggregation as well as fragmentation but there is no major difference in terms of aggregates and fragments observed for F1 and F3. As no significant difference in impurities was observed at this temperature, both (F1 and F3) the formulations were further studied at higher temperatures to increase degradation kinetics as well as the degradants.
Screening of aggregation inhibitors at 47°C and 55°C
To find out the best aggregation inhibitor between aspartic acid (F1) and glycine (F3), both the formulations were charged at 47°C as well as at 55°C. The results indicate that Glycine (F3) is showing higher degradation in terms of aggregation as well as fragmentation as compared to aspartic acid (F1) at both the temperatures tested i.e. 47°C for 16 hours (Fig. 3a & 3b) and 55°C for 24 hours (Fig. 4). Formulation containing glycine is also showing one extra fragment band (Fig. 3b)) in reducing condition at 47°C; 16 hours.
Aspartic acid is shown to be effective against aggregation as well as fragmentation at all the temperatures without any extra band compared to reference medicinal product (RMP). An extra band observed in formulation containing glycine could be contributor to immunogenicity.
Combination of Excipients (Lysine + Aspartic acid)
In order to maintain pH of F3 formulation containing Aspartic acid (shown to be effective in all temperatures as seen above), lysine buffer was added. Both Lysine and aspartic acid were used at a concentration of 10 mM as these amino acids are expected to have higher stability at equimolar concentrations. The formulation composition is mentioned in Table la:

Table la: Formulation of F5

Sr. No Components Composition F5
1. Etanercept 50 mg
2. Sucrose 20 mg
3. Phosphate Buffer 25 mM
4. Aspartic acid 10mM
5. Lysine Monohydrate 10 mM
6. Sodium Chloride 100mM
7. Polysorbate 20 0.2 mg
8. Disodium EDTA 1 mM
The formulation containing Lysine in combination with Aspartic acid (F5) showed less fragmentation compared to the formulation without lysine (F3) as seen in Figure 5a and
5b.
Example 2 Effect of EDTA
The effect of EDTA was checked in F3 formulation at 40°C for 3 days and analyzed by SE-HPLC as size exclusion chromatography separates proteins and its related impurities on the basis of their size. This technique is useful to detect aggregation and fragmentation of Etanercept and the results are given below in Table 2.
SDS PAGE was also used to compare aggregates and fragments pattern. (Figure 5a, 5b, 6a and 6b)
Table 2: SE-HPLC Results of formulations showing impact of EDTA

Type Zero Day 40°C for 3 Days

w/o EDTA with EDTA w/o EDTA with EDTA
Dimer 2.20 2.40 1.62 2.18
Oligomers 0.0007 0 0.005 0.0
Degradants 0.003 0.39 1.39 0.82
Purity 97.79 97.21 96.98 97.00
F3 was found to have less rate of degradation to that of formulation without EDTA as per SE-HPLC results particularly in terms of fragments.

BY SDS PAGE, F3 is found to have fewer amounts of low molecular weight bands after exposure of samples at 40°C for 3 days. Hence, EDTA plays an important role in preventing fragmentation of Etanercept.
Example 3 Effect of buffers
Etanercept formulations with phosphate buffer and histidine buffer as given in Table 3 (F6 and F7) were charged at 50°C for 2 days and analyzed by SE-HPLC and Differential Scanning Calorimetry (DSC). DSC is a technique used to determine thermodynamic stability of proteins. Etanercept has three transitions and Tml corresponds to TNFR, Tm2 corresponds to CH2 domain and Tm3 corresponds to CH3 domain of Fc portion (higher Tm indicates higher stability)
Table 3: Identification of buffer component

Sr.
No Components Formulation No.

F6 F7
1 Sucrose 20 mg -
2 Trehalose - 20 mg
3 Lysine Monohydrate 10 mM -
4 Glycine - 25 mM
5 Aspartic acid 10 mM 5mM
6 Sodium Chloride 100 mM 100mM
7 Polysorbate 20 0.2 mg 0.2 mg
8 Disodium EDTA 1 mM 1 mM
9 Phosphate Buffer 25 mM -
10 Histidine - 10mM
Table 4: SE-HPLC results for Buffer component identification

Formulation No. % Aggregates % Fragments % Purity
F6-0 day 1.4 0 98.6
F7-0 day 1.6 0.1 98.3
F6-2 day 12.5 0 87.5
F7-2 day 21.6 0 78.4

The composition with phosphate buffer as buffering agent was having high purity and lower aggregates compared to formulations containing histidine buffer as per SE-HPLC results.
As per DSC analysis, transition midpoints of first and second transition peak of phosphate buffer are around 1°C and 2°C respectively higher than that of histidine buffer formulation. The midpoint of third transition peak is almost similar in both the buffers.
As phosphate buffer was observed to have less degradation rate compared to histidine buffer as evidenced by SE-HPLC results and high thermodynamic stability evidenced by DSC analysis, phosphate buffer is preferred as suitable buffer system.
Example 4
Buffer salt identification
The buffer salts (Sodium and Potassium) were screened for best suitable candidate in terms of stability.
The Phosphate buffer in combination of its salts i.e. sodium / potassium was used for desired stability of protein. Table 5 summarizes the combination sets used for selecting the best formulation candidate.
Table 5: Identification of combination buffer salt and its concentration

Sr.
No Components F6 F8
1 Sucrose 20 mg 20 mg
2 Lysine Monohydrate 10 mM 10 mM
3 Aspartic acid 10 mM 10mM
4 Sodium Chloride 100 mM 100 mM
5 Polysorbate 20 0.2 mg 0.2 mg
6 Disodium EDTA 1 mM 1 mM
7 Sodium Phosphate monobasic 11 mM 11 mM
8 Sodium phosphate dibasic 13 mM -
9 Potassium phosphate dibasic - 19 mM

The thermodynamic stability of compositions was identified with the means of DSC. The aggregation and fragmentation in due course of storage was assessed by means of SE-HPLC. The results are reported in Table 6 and Table 7.
Table 6: Experimental DSC results of selected combinations

S.No. Formulations Tml Tm2 Tm3
1 RMP 57.5 70.4 82.3
2 F6 57.7 70.1 82.7
3 F8 58.3 70.1 82.3
Table 7: SE-HPLC results for buffer salt optimization

Study Temperature Duratio n (days) Formulations

RMP F6 F8
50°C 0 98.4 9S.6 98.6

2 81.4 86.1 87.5

3 75.9 Not Done 80.9
The composition with potassium salt was having high purity as compared to formulations containing sodium salt as per the SE-HPLC results.
As per DSC analysis, transition midpoint of first transition peak of potassium salt is around 1°C higher than that of sodium salt composition only. The midpoints of second and third transition peak are almost similar in both the salts.
As sodium-potassium salt combination was observed to have less degradation rate compared to sodium salt alone as evidenced by SE-HPLC results and high thermodynamic stability evidenced by DSC analysis, the sodium-potassium salt combination was chosen as suitable buffer system.
Example 5
Preparation of TNER: Fc fusion protein with aggregation inhibitors L-aspartic acid and Lysine

All the components given in the table 8 except polysorbate 20 were dissolved in 80 % of water and mixed them properly with continuous stirring. Polysorbate 20 was added in the solution by making final concentration as 0.2 mg/ml. The volume of formulation buffer was made to 90 % with water. The pH was adjusted to 6.3 with any suitable acid/base and the volume was made up to 100 % with water. The formulation buffer was filtered and the Etanercept bulk was diluted in required concentration with this filtered formulation buffer. The Etanercept formulation was analyzed by SE-HPLC, SDS-PAGE, and HIC at zero time, and after 1, 2, and 3 months storage at -20°C, 5±3°C, 25±2°C. HIC separates proteins on the basis of hydrophobicity. Peak 1 in HIC determines fragments, Peak 2 corresponds to active dimer of Etanercept and Peak 3 corresponds to aggregates. Pre-peak 1 observed in some cases corresponds to truncated impurities.
The bioactivity of samples was also checked. The method is based on principle of neutralization of cytotoxic effect. TNF-a produces cytotoxic effect on L929 (mouse connective tissue) cell line. TNFR:Fc specifically neutralizes the cytotoxic activity of TNF- a in a dose dependent manner. The bioactivity of RMP is 1.7 Million units per mg. The results are reported in Table 9.
The present pharmaceutical formulation was prepared by adding aggregation inhibitors to the purified polypeptide as described above. Further, a buffer, a tonicity modifier, a surfactant, a fragmentation inhibitor and an additional excipient can be added as needed. It will be understood by one of ordinary skill in the art that the combining of the various components to be included in the composition can be done in any appropriate order, namely, the buffer can be added first, middle or last and the tonicity modifier can also be added first, middle or last. It is also to be understood by one of ordinary skill in the art that some of these chemicals are incompatible at certain combinations, and accordingly, are easily substituted with different chemicals that have similar properties but are compatible in the relevant mixture.
Table 8

Sr.
No. Ingredient Concentration

I. TNFR:Fc 50.0 mg/ml
2. Sodium dihydrogen phosphate 1.5 mg/ml
3. Dipotassium hydrogen phosphate 3.3 mg/ml
4. Lysine 1.5 mg/ml
5. Sodium chloride 5.8 mg/ml
6. Polysorbate 20 0.1 mg/ml
7. Sucrose 20 mg/ml
8. Aspartic acid 1.3 mg/ml
9. Disodium EDTA 0.37 mg/ml
a) Stability test of TNFR:Fc aqueous formulation
The biological tests were performed in compliance with the regulations of the European Pharmacopeia.
• SDS PAGE [Aggregation (Non Reduced) and Fragmentation (Reduced)]
Due to high propensity to aggregation in case of high concentration monoclonal antibodies and fusion proteins, non-reducing SDS PAGE was utilized to assess covalent aggregates. As TNFR binds to hinge region of Fc by disulphide bonds and since there are many disulphide bonds present in Fc and TNFR, the fragmentation of proteins was checked under reducing SDS PAGE.
• SE-HPLC (Aggregation and Fragmentation)
As size exclusion chromatography separates proteins and its related impurities on the basis of their size the above technique was useful to detect aggregation and fragmentation of Etanercept.
• HIC (Aggregation, fragmentation, Truncation and Misfolding)
HIC separates proteins on the basis of hydrophobicity. Peak 1 in HIC determines fragments, Peak 2 corresponds to active dimer of Etanercept and Peak 3 corresponds to aggregates. Pre-peak 1 observed in some cases corresponds to truncated impurities. Reference profiles of HIC defining Peak 1, Peak 2 and Peak 3 are respectively given in Figure 12 (-20°C after 3 months), Figure 13 (5±3°C after 3 months), Figure 14 (25±2°C after 3 months).

• Differential Scanning Calorimetry (DSC)
DSC is a technique used to determine thermodynamic stability of protein. Etanercept has three transitions and Figure 9 is indicative that Tm 1 corresponds to TNFR, Tm2 corresponds to CH2 domain and Tm3 corresponds to CH3 domain of Fc portion (Higher the Tm determines higher stability).
• In vitro Bioassay (Bioactivity)
The method is based on principle of neutralization of cytotoxic effect. TNF-a produces cytotoxic effect on L929 (mouse connective tissue) cell line. TNFR: Fc specifically neutralizes the cytotoxic activity of TNF- a in a dose dependent manner (Figure 10). The bioactivity of RMP is 1.7 Million units per mg.
The aspects with respect to stability of aqueous formulation are captured in Table 9.

Tabic 9 - Analytical parameters for a liquid formulation of Etanercept at zero time and after storage at 5°C, 25°C and -20°C
for 1, 2 and 3 months

Assay Zero Time 1 months 2 months 5 months

-20°C 5±3°C 25±2° C -20°C 5±3° C 25±2 °C -20°C 5±3°C 25±2°C -20°C 5±3°C 25±2° C
Aggregation by SE-HPLC 1.4% 1.4% 1.4% 1.7% 1.2% 1.4% 1.8% 1.1 % 1.7% 1.7 % 1.1 % 1.9%
Fragmentation by SE-HPLC 0% 0% 0% 0.1 % 0.1 % 0.2 % 0.05 % 0.2 % 0.4 % 0.0 % 0.1 % 0.5 %
HIC Peak 1 0% 0% 0% Not
tested Not
tested Not tested 0.21 % 0.28 % 0.90 % 0.81 % 0.5 % 1.4%
HIC Peak 2 93.7 % 93.7 % 93.7% Not tested Not tested Not
tested 93.1 % 94.1 % 92.8 % 93.8% 93.6% 92.9 %
HIC Peak 3 6.3 % 6.3 % 6.3 % Not tested Not tested Not tested 6.7 % 5.7 % 6.3 % 5.4% 5.9 % 5.7 %

Example 6
Stability test of TNFR: Fe liquid formulations at 40°C
Liquid formulation comprising Etanercept having the composition given in Table 8 was prepared. Formulated solution was sterilized by using 0.2 urn filter under laminar air flow and stored at 40 °C for 1 month. The formulation was analyzed by SE-HPLC, SDS-PAGE, and HIC (Figure 15) at zero time, 7 days, 15 days. 21 days and 1 month of storage at 40°C and bioactivity was also checked. The results are reported in Table 10. Table 10: Results of stability tests for Etanercept formulation

Assay Zero Time 7 days 15 days 21 days 1 month

40°C 40°C 40°C 40°C 40°C
Aggregation by SE-HPLC 1.4% 1.9% 2.4 % 3.7% 5.7 %
Fragmentation by SE-HPLC 0% 0.3 % 0.5 % 0.6 % 1.1 %
HIC Peak 1 0% Not tested Not tested Not tested 2.7 %
HIC Peak 2 93.7 % Not tested Not tested Not tested 90.0 %
HIC Peak 3 6.3 % Not tested Not tested Not tested 7.2 %
Example 7
Stability test of TNFR: Fc liquid formulations at 50°C
Liquid formulation comprising Etanercept having the composition given in Table 8 was prepared. Formulated solution was sterilized by using 0.2 µm filter under laminar air flow and stored at 50oC for 3 days. The formulation was analyzed by SE-HPLC, SDS-PAGE, and HIC at zero time, and after 2 days and 3 days of storage at 50°C. The results are reported in Table 11.
Table 11: Results of stability tests for Etanercept formulation (50 °C)

Assay Zero Time 2 days 3 days

50°C 50°C 50°C
Aggregation by SE-HPLC 1.4% 12.5 % 19.1 %
Fragmentation by SE-HPLC 0% 0% 0%
HIC Peak 1 0% 0% 0%
HIC Peak 2 93.7 % 92.6 % 84.9 %
HIC Peak 3 6.3 % 7.4 % 15.1 %

The novel formulations of fusion protein are prepared using suitable combination of buffer, an aggregation inhibitors, tonicity modifiers, stabilizers, surfactants, chelating agents and optionally with preservative in suitable combinations thereof.
The formulation prepared by the said invention comprises an effective amount of biologically active TNFR: Fc which is used in treating inflammatory diseases in humans. They are preferably used as injectable aqueous solutions.

Claims We claim
1. A pharmaceutical formulation comprising a polypeptide containing an Fc domain of an immunoglobulin and an aggregation inhibitor, wherein the aggregation inhibitor is selected from the group consisting of aspartic acid, phenylalanine, glutamic acid, alanine, histidine and lysine.
2. A pharmaceutical formulation comprising polypeptide containing an Fc domain of an immunoglobulin, an aggregation inhibitor, buffer, a non-ionic surfactant, polyol, a stabilizer, a tonicity modifier, and a chelating agent.
3. The pharmaceutical formulation of claim 2, wherein the buffer is selected from the group consisting of sodium phosphate, histidine, potassium phosphate, sodium or potassium citrate, maleic acid, ammonium acetate, tris-(hydroxymethyl)-aminomethane (tris), acetate and diethanolamine or a combination thereof.
4. The pharmaceutical formulation of claim 2 wherein the non-ionic surfactant is selected from the group consisting of a polysorbate-based non-ionic surfactant and a poloxamer-based non-ionic surfactant or a combination thereof.
5. The pharmaceutical formulation of claim 2, wherein the polyol is selected from the group consisting of sucrose, trehalose, maltose, mannitol, xylitol, maititol and sorbitol or a combination thereof.
6. The pharmaceutical formulation of claim 2, wherein stabilizer is selected from the group consisting of amino acids such as glycine, alanine, lysine, proline and serine and their salts thereof, either alone or in combination.
7. The pharmaceutical formulation of claim 2, wherein the chelating agent is selected from the group consisting of EDTA (ethylenediamine tetraacetic acid), HEDTA (hydroxyethylenediamine triacetic acid), NTA (nitriolotriacetic acid), DTPA (Diethylenetriamine pentaacetate) and citric acid or a combination thereof.
8. The pharmaceutical formulation of claim 2, wherein the tonicity modifier is selected from the group consisting of sodium chloride, potassium chloride, sodium sulfate or a combination thereof.

9. The pharmaceutical formulation according to the claim 1 or 2, wherein the polypeptide containing an Fc domain of an immunoglobulin is selected from the group consisting of monoclonal antibody, fusion protein and TNFR;Fc.
10. A pharmaceutical formulation of TNFR:Fc comprising aspartic acid, sodium-potassium phosphate buffer, lysine, sodium chloride, sucrose, polysorbate 20 and disodium ethylene diamine tetra acetic acid wherein TNFR:Fc is present at a concentration of 10 mg/ml to 100 mg/ml.
11. The formulation of claim 10 comprising 25 to 50 mg/ml etanercept, 1 mM to 50 mM aspartic acid, 1 mM to 50 mM lysine, 10 mM to 50 mM sodium-potassium phosphate, 0.75 % to 3 % sucrose, 50 to 150 mM NaCI, 0.1 mM to 2 mM EDTA, 0.05 mg/ml to 1.0 mg/ml polysorbate 20 at pH 6.0 to pH 7.0.