Process for the preparation of a freeze-dried pharmaceutical composition containing mitomycin C

Abstract

A process is described for the preparation of freeze-dried pharmaceutical compositions of mitomycin C, which are characterized by high stability and can be rapidly reconstituted to form solutions.

Claims

1. Freeze-dried pharmaceutical composition comprising mitomycin C and urea, wherein the composition comprises urea at a concentration of 0.2 to 0.99 grams (g) per gram of composition.

2. Composition according to claim 1, which comprises urea at a concentration of 0.5 to 0.99 g per gram of composition.

3. Composition according to claim 2, which comprises urea at a concentration of 0.8 to 0.95 g per gram of composition.

4. Composition according to claim 3, which comprises urea at a concentration of 0.93 to 0.94 g per gram of composition.

5. The composition according to claim 1, which comprises the impurities D1, D2 and albomitomycin C in a total quantity of less than 2.0%, wherein the quantity of these impurities is determined according to the impurities process according to Ph Eur 8.0 Mitomycin Monograph January 2008: 1655.

6. The composition according to claim 5, which comprises the impurities D1, D2 and albomitomycin C in a total quantity of less than 1.0%, wherein the quantity of these impurities is determined according to the impurities process according to Ph Eur 8.0 Mitomycin Monograph January 2008: 1655.

7. The composition according to claim 6, which comprises the impurities D1, D2 and albomitomycin C in a total quantity of less than 0.6%, wherein the quantity of these impurities is determined according to the impurities process according to Ph Eur 8.0 Mitomycin Monograph January 2008:1655.

8. Freeze-dried pharmaceutical composition comprising mitomycin C, wherein the composition is obtainable by a process comprising freeze-drying a solution of mitomycin C, wherein the solution comprises a mixture of tert.-butanol and water, and wherein the mixture comprises 84 to 95 wt. % tert.-butanol.

Description

EXAMPLES

Example 1—Solubility and Stability of Mitomycin C in Various Solvents

(1) The solubility and stability of mitomycin C in the various solvents and solvent mixtures stated in Table 1 were investigated.

(2) TABLE-US-00001 TABLE 1 ″Solvents/solvent mixtures used″ Mitomycin C Mannitol Cosolvent Water concentration concentration No. wt.-% wt.-% [mg/g] [mg/g] 1 Water — 100 2.0 4.0 2 Tert.- 32.6 67.4 2.1 4.1 butanol 3 Ethanol 16.4 83.6 2.2 4.4 4 Isopropanol 16.2 83.8 2.2 4.3 5 Acetone 7.1 92.9 2.0 4.1

(3) For this purpose, solutions which contained 2.0 to 2.2 mg/g mitomycin C and 4.0 to 4.4 mg/g mannitol were prepared using each of these mixtures.

(4) After 1.5 hours' stirring time at room temperature and with exclusion of light, the mixtures obtained were examined for particles under irradiation with linearly polarized light. The result of the visual examination is presented in Table 2.

(5) TABLE-US-00002 TABLE 2 ″Visual examination″ Solvent/solvent Description of No. mixture wt.-% the mixtures 1 Water 100% dark blue suspension, not completely dissolved 2 Tert.-butanol dark blue clear solution, 32.6% completely dissolved 3 Ethanol 16.4% dark blue clear solution, completely dissolved 4 Isopropanol dark blue clear solution, 16.2% completely dissolved 5 Acetone 7.1% dark blue clear solution, completely dissolved

(6) Further, the content of mitomycin C and impurities in the mixtures obtained was determined after 24 hours' storage at room temperature. The corresponding results are presented in Table 3.

(7) TABLE-US-00003 TABLE 3 ″Content of mitomycin C and impurities after 24 h storage at room temperature″ Total content of impurities (D1, D2 and Solvent mixture Mitomycin C albomitomycin C) No. wt.-% content [%]* [%]** 2 Tert.-butanol 98.04 1.96 32.6% 3 Ethanol 16.4% 94.74 5.26 4 Isopropanol 16.2% 95.69 4.30 5 Acetone 7.1% 93.99 6.01 *Determination by process 1 (see Table 5) **Determination by process 2 (see Table 5)

(8) The results presented in Table 3 show that the mitomycin C in the lyophilisation solution in a mixture of tert.-butanol and water used according to the invention has particularly high stability.

(9) Further, the mixtures obtained were again examined for visible particles under irradiation with linearly polarized light after 24 hours' storage with exclusion of light at (a) room temperature and (b) 2 to 8° C. The results thus obtained are presented in Table 4.

(10) TABLE-US-00004 TABLE 4 ″Visual examination after storage for 24 h″ Solvent/solvent Storage at room Storage at No. mixture wt.-% temperature 2 to 8° C. 1 Water 100% dark blue dark blue suspension; suspension dispersed particles 2 Tert.-butanol dark blue clear dark blue clear 32.6% solution solution 3 Ethanol 16.4% dark blue clear dark blue clear solution; needle- solution; needle- like particles like particles 4 Isopropanol dark blue clear dark blue clear 16.1% solution solution; needle- like particles 5 Acetone 7.1% dark blue clear dark blue clear solution; needle- solution; needle- like particles like particles

(11) With the solvent mixtures usable according to the invention, markedly more stable solutions were obtained than with water. The solution obtained with the mixture of 32.6 wt.-% tert.-butanol and 67.4 wt.-% water proved to be the most stable, since no particles were visible in it even after 24 h both at room temperature and also at 2 to 8° C. Furthermore, in the tert-butanol-water mixture after 24 hours' storage at room temperature the content of mitomycin C was the highest and the content of impurities the lowest.

(12) Determination of the Content of Mitomycin C and of Impurities by High Pressure Liquid Chromatography

(13) The samples are each diluted to 0.5 mg/ml mitomycin C with N,N-dimethylacetamide. The reference solution contains 0.5 mg/ml mitomycin C in N,N-dimethylacetamide.

(14) TABLE-US-00005 TABLE 5 ″High pressure liquid chromatography conditions″ Process 1 Process 2 Detection: UV at 365 nm UV at 254 nm Mobile Buffer/methanol Buffer/methanol phase: 62.5/37.5, vol/vol 75/25, vol/vol Buffer: Buffer: 0.025% acetic acid in 0.025% acetic acid in 0.02M ammonium acetate 0.02M ammonium acetate Flow rate: 1.4 ml/min 2.6 ml/min

(15) Column: YMC-Pack Phenyl 4.6 mm×300 mm, 10 μm

(16) Temperature: 25° C.

(17) Injection volume: 10 μl

Example 2—Solubility and Stability of Mitomycin C in Dimethyl Sulphoxide and a Mixture of Dimethyl Sulphoxide and N,N-Dimethylacetamide

(18) The solubility and stability of mitomycin C in the solvents stated in Table 6, namely in dimethyl sulphoxide (DMSO) and a mixture of dimethyl sulphoxide (DMSO) and N,N-dimethyl-acetamide (DMAA) were investigated.

(19) TABLE-US-00006 TABLE 6 ″DMSO or DMSO/DMAA as solvent/solvent mixture″ Dimethyl N,N-Dimethylacetamide No. sulphoxide wt.-% wt.-% 6 5.7 94.3 7 100 —

(20) For this purpose, solutions using each of these solvents were prepared, which for No. 6 (DMSO/DMAA) contained 0.53 mg/g mitomycin C and 8.0 mg/g urea and for No. 7 (DMSO) 1.82 mg/g mitomycin C and 27.3 mg/g urea. The solutions were stored at room temperature and with exclusion of light for a period of up to 71.5 hours.

(21) TABLE-US-00007 TABLE 7a ″Content of mitomycin in DMSO/DMAA mixture″ DMSO/ DMAA Mitomycin content [%] wt.-% t = 0 t = 6.5 h t = 14.5 h t = 21 h t = 42 h t = 71.5 h 5.7/94.3 .sup.1 100 99.93 99.62 98.84 99.11 98.58 .sup.1 Content determined with process 3

(22) TABLE-US-00008 TABLE 7b ″Purity of mitomycin in DMSO″ DMSO Mitomycin purity [%] wt.-% t = 0 t = 4 h t = 6.5 h t = 13 h t = 20 h t = 26.5 h 100.sup.2 100 99.31 99.32 99.19 99.36 99.32 .sup.2Purity determined with process 4; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(23) In both solvents, the mitomycin C proved to be very stable. The use of DMSO alone resulted in a particularly small decrease in the original content of mitomycin C from 100% to 99.32% within a period of 26.5 hours.

(24) The content of mitomycin C and hence the stability of the solutions obtained was checked by process 3 and 4. Process 3 corresponds to the content process according to Ph Eur 8.0 Mitomycin Monograph January 2008: 1655. Process 4 corresponds to the impurities process according to Ph Eur 8.0 Mitomycin Monograph January 2008: 1655.

Example 3—Solubility and Stability of Mitomycin C in Various Tert.-Butanol/Water Mixtures

(25) The solubility and stability of mitomycin C in the various mixtures of tert.-butanol and water stated in Table 8 were investigated.

(26) For this purpose, solutions using each of these mixtures were prepared, wherein the concentration of mitomycin C was 2.1 mg/g for mixture No. 8, 2.2 mg/g for mixture No. 9 and 2.4 mg/g for mixture No. 10.

(27) These solutions were stored for 16 h with exclusion of light at (a) room temperature and (b) at 2 to 8° C. and then again examined for visible particles under irradiation with linearly polarized light. The results thus obtained are also presented in Table 8.

(28) TABLE-US-00009 TABLE 8 ″Visual examination after storage for 16 h″ Solvent mixture Storage at room Storage at 2 to No. wt.-% temperature (a) 8° C. (b) 8 tert.-butanol dark blue clear dark blue clear 32.6% solution solution 9 tert.-butanol dark blue clear dark blue clear 51.7% solution solution 10 tert.-butanol dark blue clear dark blue clear 72.9% solution solution

(29) All mixtures of tert.-butanol and water were capable of dissolving the stated quantity of mitomycin C, and in the solutions obtained no particles were visible even after 16 h storage.

(30) For the HPLC determination of the stability of mitomycin C in tert.-butanol/water mixtures, mitomycin C was added to a mixture of 20 wt.-% tert.-butanol and 80 wt.-% water (No. 11) in a quantity such as to obtain a solution with a concentration of 10 mg/g mitomycin C. Further, mitomycin C was added to a mixture of 32.6 wt.-% tert.-butanol and 67.4 wt.-% water (No. 12) in a quantity such as to obtain a solution with a concentration of 2.1 mg/g mitomycin C. Further, mitomycin C was added to a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water (No. 13) in a quantity such as to obtain a solution with a concentration of 5 mg/g mitomycin C. Further, a mitomycin-compriseing solution in pure tert.-butanol (100 wt.-%) (No. 14) and for comparison a solution in water (No. 15) were prepared. In the experiment with pure tert.-butanol, this was firstly melted by warming to about 30° C. and the mitomycin C was then dissolved in the melt.

(31) The solutions were then stored for 24 h at room temperature in brown glass vessels. The respective results are presented in Table 9.

(32) TABLE-US-00010 TABLE 9 ″Stability of mitomycin C in tert.-butanol/water mixtures″ Mitomycin Mitomycin Mitomycin purity* purity* purity* Solvent Mitomycin t = 0 h t = 6 h t = 24 h No. mixture wt.-% [mg/g] [%] [%] [%] 11 Tert.-butanol 10 99.51 97.01 93.55  20% 12 Tert.-butanol 2.1 100.0 99.4 98.7 32.6%  13 Tert.-butanol 5 99.56 98.95 98.47  89% 14 Tert.-butanol 0.38 100.0 100.0 100.0 100% 15 Water 0.48 96.8 92.1 89.9 (Reference) *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(33) In the tert.-butanol-containing solutions, the mitomycin C had high stability, wherein the use of the mixtures No. 12 and No. 13 resulted in a particularly slight decrease in the original purity at t=0 of mitomycin C from 100.0% to 98.7% and 99.56% to 98.47%. A particularly high purity of 100.0 wt.-% after 24 h could be achieved in 100 wt.-% tert.-butanol, however, the solubility of mitomycin C in pure tert.-butanol is lower.

(34) In contrast to this, the purity of mitomycin C in water after 24 h is significantly worse (at t=0 from 96.8% to 89.9%).

Example 4—Compatibility of Further Additives with Tert.-Butanol/Water Mixtures

(35) Several solutions were prepared, each by dissolving 20 mg mitomycin C in 6 g of a mixture of 89 wt.-% tert. butanol and 11 wt.-% water. The additives urea, PEG 4000 or trometamol were added to these solutions, in order in each case to give a concentration of 50 mg/g. In addition, the solution with trometamol was adjusted to a pH of 7.4 with acetic acid.

(36) At t=0 and after 6 h and 24 h at room temperature, the solutions were examined for their content of mitomycin C and compared with a solution which contained no further additive. The determination of the content was performed according to process 2, and the results are presented in Table 10.

(37) TABLE-US-00011 TABLE 10 ″Stability of solutions with urea, polyethylene glycol and trometamol″ Mitomycin C Mitomycin C Mitomycin C purity* purity* purity* Additive t = 0 t = 6 h t = 24 h Urea 99.69 99.76 99.14 PEG 4000 100 99.58 99.50 Trometamol 99.56 99.44 99.50 Without additive 99.61 99.63 99.48 *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

Example 5—Stability of Mitomycin C in Urea-Containing Tert. Butanol/Water Mixtures

(38) Urea was dissolved in a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water in a quantity such as to achieve a concentration of 5 wt.-%. Next, mitomycin C was added in a quantity such as to obtain a concentration of 3.33 mg/g, and the solution was stirred for one hour. The solution was filled into brown glass vessels and stored for 9 days at room temperature (RT) without protection against light, at room temperature (RT) with exclusion of light and at 5° C. with exclusion of light.

(39) Purity determinations according to process 2 were performed at different times. The results are presented in Table 11.

(40) TABLE-US-00012 TABLE 11 ″Stability of mitomycin solutions with urea″ Mitomycin purity* [%] Storage t = 0 t = 6 h t = 24 h t = 48 h t = 72 h t = 9 d RT; without 99.32 98.83 97.60 96.77 96.14 95.78 protection against light RT; with 99.33 98.83 97.80 97.04 96.74 96.35 exclusion of light 5° C.; with 99.23 99.18 99.20 98.86 98.80 98.21 exclusion of light *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(41) Even after nine days' storage, under all conditions, the solution was still surprisingly stable and the purity of the solution surprisingly high.

Example 6—Freeze-Drying of Solutions of Mitomycin C in Various Tert.-Butanol/Water Mixtures

(42) Firstly, solutions of mitomycin C in mixtures of tert.-butanol and water with 16.1 wt.-%, 32.6 wt.-% and 72.9 wt.-% tert.-butanol were prepared. These solutions contained 2.1 mg/g mitomycin C and 4.1 mg/g mannitol for the solution with the mixture with 16.1 wt.-% tert.-butanol, 2.2 mg/g mitomycin C and 4.3 mg/g mannitol for the solution with the mixture with 32.6 wt.-% tert.-butanol and 2.4 mg/g mitomycin C and 4.8 mg/g mannitol for the solution with the mixture with 72.9 wt.-% tert.-butanol.

(43) All solutions were clear and sufficiently stable.

(44) For comparison, a solution of mitomycin C in water, which contained 7 mg/g mannitol and because of the poor solubility in water 0.7 mg/g mitomycin C, was also prepared.

(45) By conventional freeze-drying with (i) freezing of the solutions, (ii) application of a vacuum, (iii) primary and (iv) secondary drying, lyophilisates were obtained. These were reconstituted with water, and the reconstituted solutions obtained were analysed according to Example 1 for their content of mitomycin C and of impurities. The results are presented in Table 12.

(46) TABLE-US-00013 TABLE 12 ″Content of mitomycin C and impurities after freeze-drying and reconstitution″ Quantity of tert.- Mitomycin C Impurities Content*** butanol in mixture Content** [%] Total; D1; D2; wt.-% [%] albomitomycin C Tert.-butanol 0% 98.36 1.64; 0.40; 0.48; 0.76 Tert.-butanol 16.1% 99.55 0.46; ND*; 0.15; 0.31 Tert.-butanol 32.6% 99.81 0.20; ND*; 0.10; 0.10 Tert.-butanol 72.9% 100.00 ND*; ND*; ND*; ND* *ND = not detectable, i.e. below the detection limit **HPLC determination by process 1 ***HPLC determination by process 2

(47) After lyophilisation and reconstitution, all mixtures of tert.-butanol and water used according to the invention resulted in solutions with a very high content of mitomycin C and only a very low content of impurities (D1, D2 and albomitomycin C).

(48) In contrast to this, lyophilisation using water gave a reconstituted solution with a markedly lower content of mitomycin C and a very significant quantity of impurities.

Example 7—Stability of Mitomycin C in Tert.-Butanol-Water Mixture (89/11) with 20 mg/g Urea

(49) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water were prepared. As well as 1.33 mg/g mitomycin C, the solutions also each contained 20 mg/g urea. At t=0 and after 5, 22 and 27 hours at room temperature (RT) with exclusion of light and in the refrigerator, the purity of the solutions was investigated according to process 2. The results are shown in Table 13.

(50) TABLE-US-00014 TABLE 13 ″Stability of mitomycin C in 20 mg/g urea-containing solutions″ Mitomycin C purity* [%] Conditions t = 5 h t = 22 h t = 27 h RT; with exclusion of light 99.7 99.2 98.9 5° C.; with exclusion of light 99.8 99.8 99.7 *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(51) Even after more than one day's storage at room temperature, the purity of the solution is surprisingly high, which reflects the surprisingly high stability of the active substance in the solvent.

Example 8—Stability of Mitomycin C in Tert.-Butanol-Water Mixture (89/11) with 25 mg/g Urea

(52) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water were prepared. As well as 1.67 mg/g mitomycin C, the solutions also each contained 25 mg/g urea. At t=0 and after 5, 22 and 27 hours at room temperature (RT) with exclusion of light and in the refrigerator, the purity of the solutions was investigated according to process 2.

(53) TABLE-US-00015 TABLE 14 ″Stability of mitomycin C in 25 mg/g urea-containing solutions″ Mitomycin C purity* [%] Conditions t = 5 h t = 22 h t = 27 h RT; with exclusion of light 99.6 99.1 98.6 5° C.; with exclusion of light 99.8 99.5 99.5 *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(54) Even after more than one day's storage at room temperature, the purity of the solution is surprisingly high, which reflects the surprisingly high stability of the active substance in the solvent.

Example 9—Freeze-Drying of Solutions of Mitomycin C Containing Urea or Polyethylene Glycol (50 mg/g)

(55) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water were prepared. As well as 3.33 mg/g mitomycin C, the solutions also each contained either 50 mg/g urea or PEG 4000. In each case, 6 g of these solutions was filled into small vials and freeze-dried in conventional manner. The lyophilisate cakes containing urea and PEG 4000 were firm and defect-free.

(56) The lyophilisates were analysed for the purity of mitomycin C directly after their preparation (t=0) and after storage for 1 month (t=1 month) at 40° C. The results are presented in Table 15.

(57) TABLE-US-00016 TABLE 15 ″Stability of lyophilisates with urea and polyethylene glycol″ Mitomycin purity * Reconstitution Additive [%] time t = 0; Urea 99.65 <<30 secs PEG 4000 99.34 <<30 secs t = 1 month at 40° C.; Urea 99.89 <<30 secs PEG 4000 96.19 <<30 secs * HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(58) Even after storage at an elevated temperature of 40° C., the lyophilisates produced had a high purity of mitomycin C, which reflects their very good stability.

(59) Moreover, the lyophilisates could be completely reconstituted with isotonic saline solution in very much less than 30 secs.

Example 10—Freeze-Drying of Solutions of Mitomycin C Containing Urea (20 mg/g)

(60) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol (TBA) and 11 wt.-% water were prepared. As well as 1.33 mg/g mitomycin C, the solutions also each contained 20 mg/g urea. In each case, 1.5 g of this solution was filled into small vials and freeze-dried in conventional manner. The lyophilisate cakes were firm and defect-free.

(61) The lyophilisates were analysed for the purity of mitomycin C directly after their preparation (t=0). In addition, the reconstitution time was determined. The reconstitution was effected with isotonic saline solution to an end concentration of 1 mg/g mitomycin C. The results are presented in Table 16.

(62) TABLE-US-00017 TABLE 16 ″Characteristics of urea-containing lyophilisates″ Mitomycin C purity* Reconstitution Additive [%] time t = 0 Urea 99.5 <<30 secs *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(63) The lyophilisates produced had a high purity of mitomycin C, which reflects the very good stability of the active substance during the process.

(64) Moreover, the lyophilisates could be completely reconstituted with isotonic saline solution in very much less than 30 secs.

Example 11—Freeze-Drying of Solutions of Mitomycin C Containing Urea (25 mg/g)

(65) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol (TBA) and 11 wt.-% water were prepared. As well as 1.67 mg/g mitomycin C, the solutions also each contained 25 mg/g urea. In each case, 1.2 g of this solution was filled into small vials and freeze-dried in conventional manner. The lyophilisate cakes with urea were firm and defect-free.

(66) TABLE-US-00018 TABLE 17 ″Urea-containing lyophilisates″ Mitomycin purity Reconstitution Additive [%]* time t = 0 Urea 99.5 <<30 secs *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(67) The lyophilisates produced had a high purity of mitomycin C, which reflects the very good stability of the active substance during the process. Moreover, the lyophilisates could be completely reconstituted with isotonic saline solution in very much less than 30 secs.

Example 12—Mitomycin C in Tert.-Butanol/Water Mixture (95/5) with Mannitol (45 mg/g)

(68) Solutions of mitomycin C in a mixture of 95 wt.-% tert.-butanol (TBA) and 5 wt.-% water were prepared. As well as 5 mg/g mitomycin C, the solutions also each contained 45 mg/g mannitol. In each case, 4.0 g of this solution was filled into small vials and freeze-dried in conventional manner. The lyophilisate cakes were firm and defect-free.

(69) TABLE-US-00019 TABLE 18 ″Mannitol-containing lyophilisate″ Mitomycin purity* Reconstitution Additive [%]* time t = 0 Mannitol 99.6 <<30 secs *HPLC determination by process 2; purity is defined as area of the mitomycin peak relative to the total area of all peaks in the HPLC chromatogram

(70) The lyophilisates produced had a high purity of mitomycin C, which reflects the very good stability of the active substance during the process. Moreover, the lyophilisates could be completely reconstituted with isotonic saline solution in very much less than 30 secs.

Example 13—Stability of Mitomycin Lyophilisates

(71) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol (TBA) and 11 wt.-% water were prepared. As well as 3.33 mg/g mitomycin C, the solutions also each contained 50 mg/g urea. In each case, 6 [corresponds to 20 mg mitomycin C] or 12 g [corresponds to 40 mg mitomycin C] of these solutions was filled into small vials and freeze-dried in conventional manner. The lyophilisates obtained were examined at different times t=0, t=3 months and t=6 months at 40° C. and 75% relative humidity (r.h.).

(72) The determination of the content of mitomycin C was performed by process 3 and that of the impurities content by process 4. The reconstitution was effected with 20 and 40 ml respectively of isotonic saline solution to an end concentration of 1 mg/ml.

(73) TABLE-US-00020 TABLE 19 ″Stability at 40° C. and 75% r.h. [20 mg mitomycin C]″ t = 0 t = 3 months t = 6 months Reconstitution time 7 secs 12 secs 17 secs Mitomycin C content* 97.8% 98.2% 98.3% Impurity 0.29% 0.20% 0.26% albomitomycin C** Sum of all 0.29% 0.55% 0.61% impurities** *determination by process 3 **determination by process 4

(74) TABLE-US-00021 TABLE 20 ″Stability at 40° C. and 75% r.h. [40 mg mitomycin C]″ t = 0 t = 3 months t = 6 months Reconstitution time 6 secs 20 secs 18 secs Mitomycin C 97.2% 96.6% 96.7% content* Impurity 0.32% 0.22% 0.21% albomitomycin C** Sum of all 0.32   0.55   0.58   impurities** *determination by process 3 **determination by process 4

(75) Even after 6 months' storage at elevated temperature of 40° C. and elevated atmospheric humidity of 75% r.h., the lyophilisates produced contained only very small quantities of impurities. Moreover, the lyophilisates could be completely reconstituted with isotonic saline solution in very much less than 30 secs.

Example 14—Elevated End Concentration after Reconstitution

(76) Solutions of mitomycin C in a mixture of 89 wt.-% tert.-butanol and 11 wt.-% water were prepared. As well as 3.33 mg/g mitomycin C, the solutions also each contained 50 mg/g urea. In each case, 6 g [corresponds to 20 mg mitomycin C] of these solutions was filled into small vials and freeze-dried in conventional manner. The lyophilisates obtained were reconstituted with 20 ml or 10 ml water for injection.

(77) TABLE-US-00022 Description of the Mitomycin C Mitomycin C reconstituted end concentration content* [%] solution 1 mg/ml 100.6 Clear, free from visible particles 2 mg/ml 100.6 Clear, free from visible particles *determination by process 3

(78) The reconstituted solutions in water for injection had a high content of mitomycin C. The solutions were clear and free from visible particles.