STABLE PHARMACEUTICAL COMPOSITION COMPRISING PEMETREXED OR PHARMACEUTICALLY ACCEPTABLE SALT THEREOF

Abstract

Provided is a composition of a ready-to-use injectable solution comprising pemetrexed or pharmaceutically acceptable salts thereof, containing pemetrexed; anhydrous sodium sulfite; and N-acetyl-L-cystein. With respect to use as an injectable preparation. The ready-to-use injectable solution composition is suitable for effective administration of pemetrexed since a melting process of main ingredients is not necessary before administration, and the composition can be used by being diluted immediately in a perfusate. In addition, the properties of the composition do not change even in long-term storage, and pharmaceutical stability is significantly improved by inhibiting related substances below a reference, whereby the composition can be stored in a liquid preparation state.

Claims

1. A composition of a ready-to-use pemetrexed-containing injection solution comprising pemetrexed or pharmaceutically acceptable salts thereof, as active ingredient, sodium sulfite, and N-acetyl-L-cysteine.

2. The composition of a ready-to-use injection solution according to claim 1, wherein the molar concentration ratio of pemetrexed to sodium sulfite to N-acetyl-L-cysteine is 1:0.002˜0.1:0.05˜0.3.

3. The composition of a ready-to-use injection solution according to claim 1, wherein the pH of the composition is from 6.0 to 8.5.

4. A method of preparing a ready-to-use pemetrexed-containing injection composition, comprising: (a) dissolving an excipient comprising sodium sulfite and N-acetyl-L-cysteine in water for injection or saline solution and adjusting the pH of the solution to a value of 7.0; (b) mixing and dissolving pemetrexed in the solution prepared in step (b) and adjusting the pH of the solution to a value from 6.0 to 8.5; (c) filtering the solution prepared in (b); and (d) filling a vial with the solution prepared in (c) and substituting the oxygen within the vial with nitrogen.

Description

BEST MODE

[0035] Hereinafter, the present invention will be described in detail with embodiments. However, the embodiments and experimental examples below merely exemplify the present invention and do not limit the present invention thereto.

<Examples 1 to 10> Preparation of the Pemetrexed-Containing Ready-to-Use Injection According to the Present Invention

[0036] Thoroughly dissolve D-mannitol, sodium sulfite, and N-acetyl-L-cysteine specified in the table 1 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 1 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 7.5 and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial. Designate the sealed vial as corresponding Examples 1 to 10.

TABLE-US-00001 TABLE 1 (Unit: mg) Exam- Example 1 Example 2 Example 3 Example 4 ple 5 Pemetrexed 1250 2500 2500 2500 2500 D-mannitol 1250 2500 2500 2500 2500 Sodium sulfite 3 1.5 6 6 6 N-acetyl-L- 41 245 82 147 245 cysteine 0.5N HCl q.s. q.s. q.s. q.s. q.s. 0.5N q.s. q.s. q.s. q.s. q.s. NaOH(aq) Water for q.s. q.s. q.s. q.s. q.s. injection Exam- Example 6 Example 7 Example 8 Example 9 ple 10 Pemetrexed 2500 2500 5000 5000 7500 D-mannitol 2500 2500 5000 5000 7500 Sodium sulfite 25 63 12 50 18 N-acetyl-L- 82 49 163 294 246 cysteine 0.5N HCl q.s. q.s. q.s. q.s. q.s. 0.5N q.s. q.s. q.s. q.s. q.s. NaOH(aq) Water for q.s. q.s. q.s. q.s. q.s. injection

<Examples 11 to 12> Preparation of the Pemetrexed-Containing Ready-to-Use Injection According to the Present Invention

[0037] Thoroughly dissolve D-mannitol, sodium sulfite, and N-acetyl-L-cysteine specified in the table 2 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 2 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust each of the pH of the solution to pH 6.0 and pH 8.5 respectively and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial. Designate the sealed vial as Examples 11 to 12.

TABLE-US-00002 TABLE 2 (Unit: mg) Example 11 Example 12 Pemetrexed 2500 2500 D-mannitol 2500 2500 Sodium sulfite 6 6 N-acetyl-L-cysteine 147 147 0.5N HCl q.s. q.s. 0.5N NaOH(aq) q.s. q.s. Water for injection q.s. q.s.

<Comparative Example 1> Preparation of Pemetrexed-Containing Liquid Injection not Comprising any Stabilizer

[0038] Dissolve D-mannitol specified in the table 3 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 3 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 7.5 and then filter it with 0.22 um filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial.

<Comparative Examples 2 to 11> Preparation of Pemetrexed-Containing Liquid Injection Comprising Conventional Stabilizer

[0039] Thoroughly dissolve each D-mannitol, propyl gallate, sodium citrate hydrate, ascorbic acid, sodium bisulfite, disodium edetate hydrate, butylhydroxyanisole, butylhydroxytoluene, sodium thiosulfate hydrate, sodium pyrosulfite, and L-cysteine specified in the table 3 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 3 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 7.5 and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial. Designate the sealed vial as corresponding Comparative Examples 2 to 11.

<Comparative Examples 12 to 16> Preparation of Pemetrexed-Containing Liquid Injection Comprising Sodium Sulfite Alone

[0040] Thoroughly dissolve D-mannitol and sodium sulfite specified in the table 3 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 3 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 7.5 and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial. Designate the sealed vial as corresponding Comparative Examples 12 to 16.

<Comparative Examples 17 to 19> Preparation of Pemetrexed-Containing Liquid Injection Comprising N-Acetyl-L-Cysteine Alone

[0041] Thoroughly dissolve D-mannitol and N-acetyl-L-cysteine specified in the table 3 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 3 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 7.5 and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial. Designate the sealed vial as corresponding Comparative Examples 17 to 19.

<Comparative Example 20> Preparation of Pemetrexed-Containing Liquid Injection with Different pH

[0042] Thoroughly dissolve D-mannitol, sodium sulfite, and N-acetyl-L-cysteine specified in the table 3 below in 90 mL of water for injection and apply 0.5N hydrochloric acid or 0.5N sodium hydroxide aqueous solution to adjust the solution to pH 7.0. After thoroughly dissolving the amount of pemetrexed specified in table 3 by slowly adding it to the solution, add water for injection to the solution to adjust its total volume to 100 mL. Adjust pH of the solution to 5.0 and then filter it with 0.22 μm filter. After filling a glass vial with the solution, substitute oxygen within the vial with nitrogen and seal the vial.

TABLE-US-00003 TABLE 3 (Unit: mg) Compar- Compar- Compar- Comparative ative ative ative example 1 example 2 example 3 example 4 Pemetrexed 2500 2500 2500 2500 D-mannitol 2500 2500 2500 2500 Propyl gallate 2.5 Sodium citrate 1000 hydrate Ascorbic acid 75 Sodium bisulfite Disodium edetate hydrate Butylhydroxyanisole Butylhydroxytoluene Sodium thiosulfate hydrate Sodium pyrosulfite L-cysteine Sodium sulfite N-acetyl-L-cysteine 0.5N HCl q.s. q.s. q.s. q.s. 0.5N NaOH(aq) q.s. q.s. q.s. q.s. Water for injection q.s. q.s. q.s. q.s. Compar- Compar- Compar- Comparative ative ative ative example 5 example 6 example 7 example 8 Pemetrexed 2500 2500 2500 2500 D-mannitol 2500 2500 2500 2500 Propyl gallate Sodium citrate hydrate Ascorbic acid Sodium bisulfite 2000 Disodium edetate 500 hydrate Butylhydroxyanisole 0.5 Butylhydroxytoluene 0.5 Sodium thiosulfate hydrate Sodium pyrosulfite L-cysteine Sodium sulfite N-acetyl-L-cysteine 0.5N HCl q.s. q.s. q.s. q.s. 0.5N NaOH(aq) q.s. q.s. q.s. q.s. Water for injection q.s. q.s. q.s. q.s. Compar- Compar- Compar- ative ative ative Comparative exam- exam- exam- example 9 ple 10 ple 11 ple 12 Pemetrexed 2500 2500 2500 2500 D-mannitol 2500 2500 2500 2500 Propyl gallate Sodium citrate hydrate Ascorbic acid Sodium bisulfite Disodium edetate hydrate Butylhydroxyanisole Butylhydroxytoluene Sodium thiosulfate 5 hydrate Sodium pyrosulfite 2000 L-cysteine 1700 Sodium sulfite 3 N-acetyl-L-cysteine 0.5N HCl q.s. q.s. q.s. q.s. 0.5N NaOH(aq) q.s. q.s. q.s. q.s. Water for injection q.s. q.s. q.s. q.s. Compar- Compar- Compar- ative ative ative Comparative exam- exam- exam- example 13 ple 14 ple 15 ple 16 Pemetrexed 2500 2500 2500 5000 D-mannitol 2500 2500 2500 5000 Propyl gallate Sodium citrate hydrate Ascorbic acid Sodium bisulfite Disodium edetate hydrate Butylhydroxyanisole Butylhydroxytoluene Sodium thiosulfate hydrate Sodium pyrosulfite L-cysteine Sodium sulfite 6 25 50 12 N-acetyl-L-cysteine 0.5N HCl q.s. q.s. q.s. q.s. 0.5N NaOH(aq) q.s. q.s. q.s. q.s. Water for injection q.s. q.s. q.s. q.s. Compar- Compar- Compar- ative ative ative Comparative exam- exam- exam- example 17 ple 18 ple 19 ple 20 Pemetrexed 2500 2500 5000 2500 D-mannitol 2500 2500 5000 2500 Propyl gallate Sodium citrate hydrate Ascorbic acid Sodium bisulfite Disodium edetate hydrate Butylhydroxyanisole Butylhydroxytoluene Sodium thiosulfate hydrate Sodium pyrosulfite L-cysteine Sodium sulfite 6 N-acetyl-L-cysteine 82 147 163 147 0.5N HCl q.s. q.s. q.s. q.s. 0.5N NaOH(aq) q.s. q.s. q.s. q.s. Water for injection q.s. q.s. q.s. q.s.

<Experimental Example 1> Results of Observation of Change of Property of Pemetrexed-Containing Liquid Injection

[0043] The property of the liquid injection is one of the important elements in deciding the quality of the product. Therefore, the properties of the ready-to-use pemetrexed-containing injections prepared in the above embodiments and pemetrexed-containing liquid injections prepared in the above comparative examples according to the present invention were observed after being stored in 40° C. and 60° C. conditions. The observations are shown in table 4.

TABLE-US-00004 TABLE 4 Example Stabilizer Initial 3 weeks, 60° C. 1 month, 40° C. Example 1 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 2 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 3 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 4 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 5 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 6 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 7 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 8 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 9 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 10 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 11 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Example 12 Sodium sulfite, N- clear, clear, clear, acetyl-L-cysteine colorless colorless colorless Comparative — clear, heavy yellowish example 1 colorless yellowish green green Comparative Propyl gallate clear, yellow yellow example 2 colorless Comparative Sodium citrate clear, yellow yellow example 3 hydrate colorless Comparative Ascorbic acid clear, yellow yellow example 4 colorless Comparative Sodium bisulfite clear, clear, clear, example 5 colorless colorless colorless Comparative Disodium edetate clear, yellow pale yellow example 6 hydrate colorless Comparative Butylhydroxyanisole clear, yellow yellow example 7 colorless Comparative Butylhydroxytoluene clear, yellow yellow example 8 colorless Comparative Sodium thiosulfate clear, pale yellow clear, example 9 hydrate colorless colorless Comparative Sodium pyrosulfite clear, clear, clear, example 10 colorless colorless colorless Comparative L-cysteine clear, yellow pale yellow example 11 colorless Comparative Sodium sulfite clear, clear, clear, example 12 colorless colorless colorless Comparative Sodium sulfite clear, clear, clear, example 13 colorless colorless colorless Comparative Sodium sulfite clear, clear, clear, example 14 colorless colorless colorless Comparative Sodium sulfite clear, clear, clear, example 15 colorless colorless colorless Comparative Sodium sulfite clear, clear, clear, example 16 colorless colorless colorless Comparative N-acetyl-L- clear, pale yellow pale yellow example 17 cysteine colorless Comparative N-acetyl-L- clear, pale yellow pale yellow example 18 cysteine colorless Comparative N-acetyl-L- clear, pale yellow pale yellow example 19 cysteine colorless Comparative Sodium sulfite, N- clear, clear, clear, example 20 acetyl-L-cysteine colorless colorless colorless

[0044] Pemetrexed-containing injection is clear and has colorless when it is prepared. However, as shown in table 4, comparative example 1, that does not comprise any stabilizer, shows the change of property after it is stored in 60° C. for 3 weeks and 40° C. for 1 month.

[0045] Also, most of the stabilizers used in the conventional ready-to-use injection medications show the change of property after being stored in 60° C. for 3 weeks and 40° C. for 1 month. In other words, comparative example 2 (propyl gallate), comparative example 3 (sodium citrate hydrate), comparative example 4 (ascorbic acid), comparative example 6 (disodium edentate hydrate), comparative example 7 (butylhydroxyanisole), comparative example 8 (butylhydroxytoluene), comparative example 11 (L-cysteine), and comparative examples 17 to 19 (N-acetyl-L-cysteine) show the change of property after being stored in 60° C. for 3 weeks and 40° C. for 1 month.

[0046] However, embodiments 1 to 12 (sodium sulfite+N-acetyl-L-cysteine), according to the present invention, do not show the change of property in the storage conditions mentioned above. Comparative example 5 (sodium bisulfite), comparative example 10 (sodium pyrosulfite), comparative examples 12 to 16 (sodium sulfite), and comparative example 20 (sodium sulfite+N-acetyl-L-cysteine), also, do not show the change of property in the above storage conditions. Comparative example 9 (sodium thiosulfate hydrate), also, does not show the change of property after being stored in 40° C. for 1 month.

[0047] Meanwhile, as shown in table 4, embodiments 1 to 12 in accordance with the present invention, ranging in pH from 6.0 to 8.5, and comparative example 20, which is prepared with the same composition of embodiment 4 but has the pH of 5.0, do not show any change of property. among the other comparative examples with the same pH, some show the change of property and some do not, depending on the type of stabilizers. Therefore, it can be seen that the stability of property of liquid composition for pemetrexed-containing injection is not affected by pH. However, as in the present invention, the liquid compositions for the pemetrexed-containing injections ranging from pH 5.0 to 8.5 show stability in property when sodium sulfite and N-acetyl-L-cysteine are used in combination as the stabilizers of the compositions.

[0048] Therefore, it shows that the sodium sulfates or sodium sulfites are the stabilizers that do not change the property of the liquid composition of pemetrexed-containing injection.

[0049] Also, comparative examples 17 to 19 (N-acetyl-L-cysteine), which use N-acetyl-L-cystein alone, show the change of property, whereas, embodiments 1 to 12 according to the present invention, which comprise sodium sulfite and N-acetyl-L-cysteine in combination as the stabilizers, show no change of property, which is an unprecedented phenomenon.

<Experimental Example 2> Results of Evaluation of the Stability of Total Related Substances in Pemetrexed-Containing Liquid Injection

[0050] The pemetrexed-containing ready-to-use injections, prepared in the above embodiments according to the present invention, and the pemetrexed-containing liquid injection, prepared in comparative examples, are stored in the 60° C. and 40° C. conditions. The total related substances are measured and shown in table 5. The results are evaluated using the commercially available Alimta® injection as the standard, which has the total related substances within 1.5%.

TABLE-US-00005 TABLE 5 3 month, Initial Total 40° C. related 3 weeks, 60° C. Total related substance Total related substance Example Stabilizer (%) substance (%) (%) Example 1 Sodium sulfite, N- 0.37 0.91 0.92 acetyl-L-cysteine Example 2 Sodium sulfite, N- 0.28 0.56 0.54 acetyl-L-cysteine Example 3 Sodium sulfite, N- 0.05 0.34 0.64 acetyl-L-cysteine Example 4 Sodium sulfite, N- 0.58 0.56 0.49 acetyl-L-cysteine Example 5 Sodium sulfite, N- 0.15 0.63 0.92 acetyl-L-cysteine Example 6 Sodium sulfite, N- 0.44 0.72 1.16 acetyl-L-cysteine Example 7 Sodium sulfite, N- 0.49 0.85 0.97 acetyl-L-cysteine Example 8 Sodium sulfite, N- 0.32 0.38 0.92 acetyl-L-cysteine Example 9 Sodium sulfite, N- 0.56 0.64 0.98 acetyl-L-cysteine Example 10 Sodium sulfite, N- 0.22 0.32 0.68 acetyl-L-cysteine Example 11 Sodium sulfite, N- 0.47 0.58 0.75 acetyl-L-cysteine Example 12 Sodium sulfite, N- 0.49 0.61 0.71 acetyl-L-cysteine Comparative — 0.31 2.47 1.58 example 1 Comparative Propyl gallate 0.55 1.99 2.31 example 2 Comparative Sodium citrate 0.35 0.93 1.93 example 3 hydrate Comparative Ascorbic acid 0.54 2.14 2.45 example 4 Comparative Sodium bisulfite 1.24 1.58 2.66 example 5 Comparative Disodium edetate 0.87 1.54 2.46 example 6 hydrate Comparative Butylhydroxyanisole 0.41 1.78 2.13 example 7 Comparative Butylhydroxytoluene 0.49 1.85 1.97 example 8 Comparative Sodium thiosulfate 0.56 1.37 1.74 example 9 hydrate Comparative Sodium pyrosulfite 0.81 0.92 1.88 example 10 Comparative L-cysteine 0.37 1.14 1.80 example 11 Comparative Sodium sulfite 0.27 1.84 2.10 example 12 Comparative Sodium sulfite 0.36 0.66 1.30 example 13 Comparative Sodium sulfite 0.42 0.54 1.66 example 14 Comparative Sodium sulfite 0.59 0.81 1.95 example 15 Comparative Sodium sulfite 0.41 0.59 1.11 example 16 Comparative N-acetyl-L-cysteine 0.33 1.55 1.24 example 17 Comparative N-acetyl-L-cysteine 0.27 1.31 1.19 example 18 Comparative N-acetyl-L-cysteine 0.32 1.20 0.94 example 19 Comparative Sodium sulfite, N- 0.65 0.90 1.01 example 20 acetyl-L-cysteine

[0051] If the measured total related substances of a preparation is within 1.5% in the 60° C. condition, which is a harsh heat condition, the preparation is stable in high temperature. Therefore, this means that the preparation can be stably stored under the long-term storage condition (25° C. 60% RH) and accelerated storage condition (40° C. 70% RH) for a long period of time.

[0052] As shown in the table 5, the total related substances of comparative example 1, which is the liquid injection that does not comprise any stabilizer, is above the standard 1.5%. Therefore pemetrexed-containing liquid injections need to contain the stabilizers to prevent the formation of related substances.

[0053] All of the total related substances measured in embodiments 1 to 12 (sodium sulfite and N-acetyl-L-cysteine), in accordance with the present invention, are below 1.5%.

[0054] However, amongst the comparative examples, comparative examples 17 to 19 (N-acetyl-L-cysteine), which show the change of property after being stored in 60° C. for 3 weeks and 40° C. for 1 month, show contrasting results from each other on the measurement of the total related substances. The total related substances of comparative examples 18 to 19 (N-acetyl-L-cysteine) are below 1.5%, but that of comparative example 17 (N-acetyl-L-cysteine) is above 1.5% of the total related substances. In other words, the formation of related substances of pemetrexed is variably inhibited depending on the concentration of N-acetyl-L-cysteine, but the change of property of pemetrexed within the solution with the same concentration of N-acetyl-L-cysteine is not inhibited.

[0055] Also, when sodium sulfite (comparative example 5), sodium thiosulfate (comparative example 9), sodium pyrosulfite (comparative example 10), and anhydrous sodium sulfite (comparative examples 12 to 16) are used alone as stabilizers for the composition of pemetrexed-containing liquid injection, the change of property does not occur in all of the above compositions but the degree of total related substances formed are very different from each other. In other words, the total related substances of comparative examples 13 and 16 show below 1.5%, whereas the total related substances of comparative example 5 (sodium bisulfite), comparative example 9 (sodium thiosulfate), and comparative example 10 (sodium pyrosulfite) are above 1.5%.

[0056] Also, the total related substances of the stabilizers of the conventional ready-to-use injection preparation, which are comparative example 2 (propyl gallate), comparative example 3 (citric acid), comparative example 4 (ascorbic acid), comparative example 6 (sodium edetate), comparative example 7 (butylhydroxyanisole), and comparative example 8 (butylhydroxytoluene), are above 1.5%.

[0057] Meanwhile, the total related substances of comparative example 20, which is prepared with the same composition as embodiment 4 in accordance with the present invention and adjusted to pH 5.0, is higher than the standard in contrast with the results of the present invention. Therefore, although the relationship between pH and formation of the related substances is not clearly investigated, the pemetrexed-containing liquid compositions according to the present invention are in the range of pH 6.0 to 8.5.

[0058] Therefore, using sodium sulfite and N-acetyl-L-cysteine in combination is necessary to inhibit the formation of the total related substances of pemetrexed-containing liquid composition. The composition of the ready-to-use pemetrexed-containing injection solution according to the present invention can suppress the formation of the total related substances within the standard value in the range of pH 6.0 to 8.5.

[0059] The embodiments, according to the present invention, as shown in experimental examples 1 and 2 above, show favorable degree of change of property and form the total related substances within the standard. Hereinafter, comparative examples 12 to 16, which show contrasting amount of the total related substances to each other, are compared with embodiments in accordance with the present invention to verify the degree of the formation of the individual related substance and evaluate the stability of the individual related substance of the solutions with varying pemetrexed to sodium sulfite ratio.

<Experimental Example 3> Evaluation of Stability of Individual Related Substance of Pemetrexed-Containing Liquid Injection

[0060] The individual related substances of the pemetrexed liquid preparations prepared in the above embodiments and comparative examples stored in 60° C. and 4° C. conditions are measured and shown in table 6. The results are evaluated using the individual related substance of the commercially available Alimta® injection as the standard, which is within 0.2%.

TABLE-US-00006 TABLE 6 Initial 3 weeks, 60° C. 2 weeks, 4° C. Individual related substance at RRT0.45 (%) Example 1 0.04 0.01 0.02 Example 2 not detected not detected not detected Example 3 not detected not detected 0.05 Example 4 0.07 not detected 0.05 Example 5 0.05 not detected not detected Example 6 0.05 not detected 0.15 Example 7 0.11 0.05 0.20 Example 8 0.03 0.01 0.04 Example 9 0.05 not detected 0.14 Example 10 0.02 not detected 0.03 Example 11 0.08 0.03 0.11 Example 12 0.03 not detected 0.11 Comparative 0.05 not detected 0.11 example 12 Comparative 0.06 not detected 0.14 example 13 Comparative 0.07 not detected 0.28 example 14 Comparative 0.07 not detected 0.35 example 15 Comparative 0.05 not detected 0.12 example 16 Individual related substance at RRT0.88 (%) Example 1 0.05 0.09 0.01 Example 2 0.03 0.03 not detected Example 3 not detected 0.08 not detected Example 4 0.06 0.11 0.02 Example 5 not detected 0.07 not detected Example 6 0.06 0.15 0.06 Example 7 0.03 0.07 0.02 Example 8 not detected 0.06 not detected Example 9 0.02 0.15 not detected Example 10 not detected 0.05 not detected Example 11 0.06 0.13 0.02 Example 12 0.06 0.03 0.02 Comparative 0.03 1.6  0.04 example 12 Comparative 0.05 0.38 0.08 example 13 Comparative 0.08 0.18 0.09 example 14 Comparative 0.07 0.17 0.12 example 15 Comparative 0.06 0.25 0.07 example 16

[0061] As shown in the table 6, the pemetrexed-containing liquid injections show different patterns of formation of the individual related substance depending on the concentration of the sodium sulfite.

[0062] In other words, when the ratios of pemetrexed:sodium sulfite of comparative examples 12, 13, and 16 are below 1:0.008, the individual related substance at RRT0.88 sharply increase in the 60° C. condition. However, even though the molar concentration ratios of pemetrexed:sodium sulfite of embodiments 1 to 5, 8, and 10 to 12, in accordance with the present invention, are below 1:0.008 and, in particular, that of embodiment 2 is 1:0.002, the stability during the storage is maintained, unlike the comparative examples above, because sodium sulfite and N-acetyl-L-cysteine are used in combination. Therefore, the stabilities of the embodiments of the present invention are maintained during the storage when the ratios of pemetrexed:sodium sulfite are 1:0.002 or above. The molar concentration ratio of pemetrexed:N-acetyl-L-cysteine of the above solutions is 1:0.050.3.

[0063] Also, as shown in comparative examples 14 and 15, when the ratio of pemetrexed:sodium sulfite is above 1:0.034, the individual related substance at RRT0.45 sharply increases in 4° C. condition and exceeds 0.2%, which is the standard value used to determine the stability of the ready-to-use pemetrexed-containing injection. However, even though the molar concentration ratios of pemetrexed:sodium sulfite of embodiments 6, 7, and 9, in accordance with the present invention, are 1:0.034 or more and, in particular, the molar concentration ratio of pemetrexed:sodium sulfite of embodiment 7 is 1:0.085, the stability during the storage is maintained, unlike the comparative examples above, because sodium sulfite and N-acetyl-L-cysteine are used in combination. Therefore, even if the ratio of pemetrexed:sodium sulfite is 1:0.085, the stability of the embodiment of the present invention is maintained during the storage. The molar concentration ratio of pemetrexed:N-acetyl-L-cysteine of the above solutions is 1:0.05˜0.3.

[0064] Therefore, in order to stabilize the individual related substance of the composition of the ready-to-use pemetrexed-containing injection solution, sodium sulfite and N-acetyl-L-cysteine need to be used in combination. As shown in the experimental examples above, when the ratio of pemetrexed:sodium sulfite:N-acetyl-L-cysteine is 1:0.002˜010.05˜0.3, the individual related substance is controlled below the standard.

<Experimental Example 4> The Change of Content and Solubility During the Storage of the Pemetrexed-Containing Liquid Injections

[0065] The changes of content of the ready-to-use pemetrexed-containing injections according to the embodiments of the present invention during the storage are evaluated. After the pemetrexed-containing injections prepared in embodiments 4, 11, and 12, in accordance with the present invention and pemetrexed-containing injections prepared in comparative examples 1 and 20 are stored under the storage conditions specified in the table 7 below, they measured with content analysis method. The results are shown in the table 7 below.

TABLE-US-00007 TABLE 7 2 weeks, Initial 3 months, 25° C. 4° C. Content (%) Content (%) Content (%) Example 4 100.5 100.4 100.5 Example 11 99.6 100.1 99.9 Example 12 100.3 100.3 100.3 Comparative example 1 99.8 98.7 99.7 Comparative example 100.5 90.1 75.6 20

[0066] As shown in the table 7, the contents of the products of embodiments 4, 11, and 12, in accordance with the present invention, during the storage are stably maintained. Whereas, comparative example 1 shows very little change under the 2 weeks, 4° C. storage condition but shows about 1% change of the content under the 3 months, 25° C. storage condition. Particularly, comparative example 20 shows about 10% decline of the content under 3 months, 25° storage condition and show even greater decline under the 2 weeks, 4° C. storage condition.

[0067] Also, embodiments 4, 11, and 12, in accordance with the present invention, do not show any formation of precipitate during storage, whereas, the comparative example 20, which has the same composition as embodiment 4 but is adjusted to pH 5.0, shows precipitate.

[0068] Therefore, the ready-to-use pemetrexed-containing injection of the present invention does not change in contents and maintains stability of the solubility.