PROCESS FOR THE PREPARATION OF IRON (HP

CARBOXYMALTOSE COMPLEX

FIELD OF THE INVENTION

The present invention related to novel processes for the preparation of iron (III) carboxymaltose complex.

BACKGROUND OF THE INVENTION

Water-soluble iron carbohydrate complexes which are used for the treatment of iron deficiency anaemia, their preparation, medicaments containing them and their use for the prophylaxis or treatment of iron deficiency anaemia. The medicaments are especially useful for parenteral application.

Ferric carboxymaltose was indicated for treatment of iron deficiency. The ferric carboxymaltose is marketed by Vifor France SA under the brand Ferinject.

U.S. Patent Application Publication No. 2006/0205691 disclosed water- soluble iron carbohydrate complexes which are obtainable from an aqueous solution of an iron (III) salt and an aqueous solution of the oxidation product of one or more maltodextrins, using an aqueous hypochlorite solution. The process disclosed in the Patent application used large amounts of sodium carbonate and hence the product obtained is contaminated with sodium carbonate.

Similar process also described in PCT Publication No. WO 2007/081744.

Product obtained in the prior art process is not suitable for the preparation of medicament without further purification methods such as crystallization method because of high content of chlorides.

The preparation of iron (III) carboxymaltose complexes using ferric hydroxide is not known.

We discovered a novel processes for the preparation of iron (III) carboxymaltose complex using ferric hydroxide. The object of the present invention is to provide improved and commercially viable processes for the preparation of iron (III) carboxymaltose complex. The iron (III) carboxymaltose complex which are produced in the present invention can directly be used for production of medicaments even without further purification because of the less chloride content. Moreover, lesser amounts of base are sufficient for the preparation of iron (III) carboxymaltose complex according to the process of the invention.

SUMMARY OF THE INVENTION

In one aspect of the present invention there is provided a process for the preparation of water soluble iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises:

a. oxidizing one or more maltodextrins using an aqueous sodium hypochlorite solution to obtain a solution; and

b. reacting the aqueous solution obtained in step (a) with ferric hydroxide to obtain iron (III) carboxymaltose complex where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40. In another aspect of the present invention there is provided a process for the preparation of water soluble iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises adding sodium hypochlorite to a mixture of one or more maltodextrins and ferric hydroxide in the presence of water to obtain iron (III) carboxymaltose complex where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40.

In another aspect of the present invention there is provided a process for the preparation of iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises:

a. heating a mixture of one or more maltodextrins, ferric hydroxide and water to obtain a iron maltodextrin complex; and b. oxidizing the iron maltodextrin complex obtained in step (a) using an aqueous sodium hypochlorite solution; and

c. maintaining at 25°C to 125°C at pH 5 to 12 to obtain iron (ΠΙ) carboxymaltose complex.

where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40.

DETAILED DESCRIPTION OF THE INVENTION

According to one aspect of the present invention, there is provided a process for the preparation of water soluble iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises:

a. oxidizing one or more maltodextrins using an aqueous sodium hypochlorite solution to obtain a solution; and

b. reacting the aqueous solution obtained in step (a) with ferric hydroxide to obtain iron (III) carboxymaltose complex where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40. In order to prepare the liginds of the complex of the invention, the maltodextrins are oxidized in an aqueous solution with a sodium hypochlorite solution.

The oxidation may be carried out in an alkaline solution at a pH of 8 to 12. The oxidation may be carried out at 15 to 40°C and preferably 25 to 35°C. The oxidation may be carried out for 10 minutes to 4 hours and preferably 1 hour to 1 hour 30 minutes.

Optionally, the oxidation may be carried out in presence of the catalyst such as alkali bromides, for example sodium bromide. The amount of catalyst is not critical. The amount is kept as low as possible in order to achieve an end product (Fe-complex) which can easily be purified. Catalytic amounts are sufficient.

In order to prepare the complex of the invention the obtained oxidized maltodextrins are reacted with ferric hydroxide. In order to do so, the oxidized maltodextrins can be isolated and redissolved; however, it is also possible to use the obtained aqueous solutions of the oxidized maltodextrins directly for the further reaction with ferric hydroxide. For instance, the aqueous solution of the oxidized maltodextrin can be mixed with ferric hydroxide in order to carry out the reaction.

Preferably freshly prepared ferric hydroxide is used in step (b).

The reaction of the contents of step (a) with ferric hydroxide may preferably be carried out at a pH between 5 to 14. If necessary, the pH is adjusting preferably using a stronger base. Examples of strong bases are alkali-or alkaline earth-hydroxides such as sodium hydroxide.

The reaction is carried out at 15°C to 125°C. It is preferred to raise the temperature gradually. Thus, for example, it is possible to heat to about 15 to 70°C and then raise the temperature gradually up to 125 C.

Optionally, the reaction is earned out under pressure.

The reaction is preferably carried out for 15 minutes to 4 hours depending on the reaction conditions.

As the preferred embodiment of the invention, wherein the reaction is first maintained at pH of 10 to 12 at 40 to 60°C then the reaction is continued in the pH of 4 to 7 at 85°C to 125°C.

The pH can be lowered, if necessary, by addition of an acid. It is possible to use inorganic or organic acids or mixture thereof, especially hydrogen halide acids such as aqueous hydrochloric acid.

After the reaction, the obtained solution can be cooled to room temperature and can optionally be diluted and optionally be filtered. After cooling, the pH can be adjusted to 5 to 7, by the addition of an acid or base. It is possible to use the acids and bases which have been mentioned for carrying out the reaction. The solutions obtained are purified and can directly be used for the production of medicaments. However, it is also possible to isolate the iron (III) complex from the solution by precipitation with an alcohol such as an alkanol, for example, ethanol.

According to another aspect of the present invention there is provided a process for the preparation of water soluble iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises adding sodium hypochlorite to a mixture of one or more maltodextrins and ferric hydroxide in the presence of water to obtain iron (III) carboxymaltose complex where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40.

In order to prepare the iron (III) carboxymaltose complex of the invention, oxidation of maltodextrins from a mixtute of maltodextrins and ferric hydroxide in an aqueous solution with a sodium hypochlorite solution.

Preferably freshly prepared ferric hydroxide is used.

The oxidation may be carried out in an alkaline solution at a pH of 8 to 12. The oxidation may be carried out at 15 to 40°C and preferably 25 to 35°C. The oxidation may be carried out for 10 minutes to 4 hours and preferably 1 hour to 1 hour 30 minutes.

Optionally, the oxidation may be carried out in presence of the catalyst such as alkali bromides, for example sodium bromide. The amount of catalyst is not critical. The amount is kept as low as possible in order to achieve an end product (Fe-complex) which can easily be purified. Catalytic amounts are sufficient.

The pH is raised to values in between 5 to 14. The pH is adjusting preferably using a stronger base. Examples of strong bases are alkali-or alkaline earth-hydroxides such as sodium hydroxide. The reaction is carried out at 15 C to 125 C. It is preferred to raise the temperature gradually. Thus, for example, it is possible to heat to about 15 to 70°C and then raise the temperature gradually up to 125°C.

Optionally, the reaction is carried out under pressure.

The reaction is preferably carried out for 15 minutes to 4 hours depending on the reaction conditions.

As the preferred embodiment of the invention, wherein the reaction is first maintained at pH of 10 to 12 at 40 to 60°C then the reaction is continued in the pH of 4 to 7 at 85°C to 125°C.

The pH can be lowered, if necessary, by addition of an acid. It is possible to use inorganic or organic acids or mixture thereof, especially hydrogen halide acids such as aqueous hydrochloric acid.

After the reaction, the obtained solution can be cooled to room temperature and can optionally be diluted and optionally be filtered. After cooling, the pH can be adjusted 5 to 7, by the addition of an acid or base. It is possible to use the acids and bases which have been mentioned for carrying out the reaction. The solutions obtained are purified and can directly be used for the production of medicaments. However, it is also possible to isolate the iron (III) complex from the solution by precipitation with an alcohol such as an alkanol, for example, ethanol.

According to another aspect of the present invention there is provided a process for the preparation of iron (III) carboxymaltose complex on the basis of the oxidation products of maltodextrins, which comprises:

a. heating a mixture of one or more maltodextrins, ferric hydroxide and water to obtain a iron maltodextrin complex;

b. oxidizing the iron maltodextrin complex obtained in step (a) using an aqueous sodium hypochlorite solution; and

c. maintaining at 25°C to 125°C at pH 5 to 12 to obtain iron (III) carboxymaltose complex.

where, when one maltodextrin is applied, its dextrose equivalent lies between 4 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 4 and 20 and the dextrose equivalent of each individual maltodextrins contained in the mixture lies between 2 and 40.

As the preferred embodiment of the invention, wherein the pH is maintained during the reaction in step (a) to ranges in between 5 to 14, the heating may be carried out at 50°C to boiling point. Preferably the heating may be carried out at 70 to 90°C and more preferably the heating may be carried out at about 90°C.

Preferably freshly prepared ferric hydroxide is used in step (a).

The oxidation in step (b) may be carried out in an alkaline solution at a pH of 8 to 12. The oxidation may be carried out at 15 to 40°C and preferably 25 to 35°C. The oxidation may be carried out for 10 minutes to 4 hours and preferably 1 hour to 1 hour 30 minutes.

Optionally, the oxidation may be carried out in presence of the catalyst such as alkali bromides, for example sodium bromide. The amount of catalyst is not critical. The amount is kept as low as possible in order to achieve an end product (Fe-complex) which can easily be purified. Catalytic amounts are sufficient.

The pH is adjusting preferably using a stronger base. Examples of strong bases are alkali-or alkaline earth-hydroxides such as sodium hydroxide.

The reaction in step (c) is carried out at 25°C to 125°C. It is preferred to raise the temperature gradually. Thus, for example, it is possible to heat to about 25 to 70°C and then raise the temperature gradually up to 125°C.

Optionally, the reaction is carried out under pressure.

The reaction is preferably carried out for 15 minutes to 4 hours depending on the reaction conditions.

As the preferred embodiment of the invention, wherein the reaction is first maintained at pH of 10 to 12 at 40 to 60°C then the reaction is continued in the pH of 4 to 7 at 85°C to 125°C. The pH can be lowered, if necessary, by addition of an acid. It is possible to use inorganic or organic acids or mixture thereof, especially hydrogen halide acids such as aqueous hydrochloric acid.

After the reaction, the obtained solution can be cooled to room temperature and can optionally be diluted and optionally be filtered. After cooling, the pH can be adjusted to 5 to 7, by the addition of an acid or base. It is possible to use the acids and bases which have been mentioned for carrying out the reaction. The solutions obtained are purified and can directly be used for the production of medicaments. However, it is also possible to isolate the iron (III) complex from the solution by precipitation with an alcohol such as an alkanol, for example, ethanol.

According to the processes of the present invention, the iron content of the obtained iron (III) carboxymaltose complex is 10 to 40% weight/weight, especially, 20 to 35% weight/weight. Iron content is measured by using Atomic Absorption Spectrophotometer (A AS). They can easily be dissolved in water. It is possible to prepare neutral aqueous solutions which have an iron content of 1% weight/vol. to 20% weight/vol. Such solutions can be sterilised by general methods. The weight average molecular weight of the obtained complex is in ^• between 80 kDa to 700 kDa, preferably 80 kDa to 350 kDa, more preferably up- to 300 kDa measured by the following method:

Mobile phase:

• Weigh accurately about 3.56 g of sodium phosphate dihydrate, 2.76g of monobasic sodium phosphate and 0.20g of sodium azide in to a 1 liter standard volumetric flask containing 800ml water.

· Mix and dissolve the contents.

• Make up to the mark with water.

System suitability solution :-

• Weigh accurately about 200.0 mg of high molecular weight dextran (Mw value 10,00,000 Da to 20,00,000 Da and Mw/ Mn value 1.0 to 1.8) and 100.0 mg of glucose in to a 20 ml volumetric flask and make up to the volume with mobile phase. Standard solution-1: -

• Weigh accurately about 20.0 mg of 5900 Da molecular weight standard in to a 5 ml volumetric flask.

• Add 4 ml of mobile phase.

Standard solution-2: -

• Weigh accurately about 20.0 mg of 11,800 Da molecular weight standard in to a 5 ml volumetric flask

• Add 4 ml of mobile phase.

Standard solution-3: - · Weigh accurately about 20.0 mg of 22,800 Da molecular weight standard in to a 5 ml volumetric flask

• Add 4 ml of mobile phase.

Standard solution-4: -

• Weigh accurately about 20.0 mg of 47,300 Da molecular weight standard in to a 5 ml volumetric flask

• Add 4 ml of mobile phase.

Standard soIution-5: -

• Weigh accurately about 20.0 mg of 112,000 Da molecular weight standard in to a 5 ml volumetric flask

· Add 4 ml of mobile phase.

Standard solution-6: -

• Weigh accurately about 20.0 mg of 212,000 Da molecular weight standard in to a 5 ml volumetric flask

• Add 4 ml of mobile phase.

Standard solution-7: -

• Weigh accurately about 20.0 mg of 404,000 Da molecular weight standard in to a 5 ml volumetric flask

• Add 4 ml of mobile phase.

Allow each standard solution to stand at or below 25°C for a minimum of 12 hours. After the agglomerate particles of each standard solution have swelled to their fullest extent, gently swirl each standard solution until dissolved.

Sample preparation:

• Transfer 5.0 ml of iron carboxymaltose complex in to a 10-ml volumetric flask.

• Make up to the volume with mobile phase.

Chromatographic system:

Detector Refractive index detector (RID)

Cell temperature 45° C

Columns Waters, Ultrahydrogel 7.8-mmX30-cm 1000 A ⁰

Waters, Ultrahydrogel 7.8-mmX30-cm 120 A ⁰

Columns temperatures 45+2 ^u C

Flow rate 0.5 mL per minute.

Run Time 50 min.

GPC software GPC for Class-VP 1.02 version

System suitability:

• Equilibrate the columns and system for 1 hour.

• ^' Inject exactly 25μΙ _^ of mobile phase in to the system and record the chromatogram to a run time of 50 minutes as a blank.

• Program the data processor to inhibit the peaks due to blank.

• Inject exactly 25μΙ, of system suitability solution in to the system and record the chromatogram to a run time of 50minutes.

• Calculate the resolution between high molecular weight dextran and glucose. Requirement:

The resolution, between high molecular weight dextran and glucose should not be less than 4.0.

Procedure:

• Inject exactly 25uL of each standard solution separately and record the chromatograms to a run time of 50minutes. • Inject exactly 25μΙ_, of Iron carboxymaltose complex and record the chromatogram.

• Enter the retention times and Molecular weights of standard solutions in the GPC software to generate a calibration curve.

· Calculate the correlation coefficient of calibration curve.

Note: Correlation coefficient of calibration curve should not be less than 0.98.

• Superimpose the chromatogram of the Iron carboxymaltose complex on the calibration curve.

• Record the weight average molecular weight (Mw).

The following examples are given for the purpose, of. illustrating, the present invention and should not be considered as limitations on the scope and spirit of the invention.

Examples

Example 1

Ferric chloride (61.5 gm) was dissolved in water (750 ml) and filtered to remove undissolved material. The resulting solution was cooled to 5 to 10°C.

To the above solution was added slowly sodium carbonate solution (61.5 gm dissolved in 750 ml water) at 5 to 10°C. The reaction mixture was stirred for 10 minutes at 5 to 10°C and then again stirred for 1 hour at ambient temperature. The separated solid was filtered and washed with water to obtain ferric hydroxide. Example 2

To sodium hypochlorite solution (68 gm) containing 2.79 gm of Active chlorine was added maltodextrin (50 gm, 14.2 dextrose equivalent), water (100 ml) and sodium bromide (0.35 gm). The resulting solution was stirred for 5 minutes at ambient temperature and then the pH of the reaction mass was adjusted to 11 with dilute sodium hydroxide solution, and maintained for 1 hour 30 minutes. Then added to a mixture of freshly prepared ferric hydroxide (as prepared in example 1 from 61.5g of ferric chloride) and water (100 ml). And then pH of the reaction mass adjusted to 11 with dilute Sodium hydroxide solution. The resulting mixture was heated to 50°C and maintained for 30 minutes, and then the pH of the reaction mass adjusted to 6 with dilute hydrochloric acid. The reaction mass was maintained for 30 minutes at 50°C and followed by maintained for 30 minutes at 96 to 98°C. The solution was cooled to ambient temperature to obtain iron carboxymaltose complex.

Molecular Weight = 3,00,000 Da

Example 2a

The iron carboxymaltose complex as obtained in example 2 was precipitated by using ethanol. Added iron carboxymaltose solution (50 gm) obtained above to ethanol (1400 ml) and stirred for 3 hours at ambient temperature. The solid obtained was collected by filtration, washed with ethanol and the solid dried at 50°C under vacuum for 2 hours to obtain iron carboxymaltose powder.

Molecular Weight = 2,96,580 Da

Iron content = 21% W/W

Example 3

Example 2 was repeated using maltodextrin (6 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 2,58,000 Da Iron content 25 mg/gm

Example 4

Example 2 was repeated using a mixture of maltodextrin (6 dextrose equivalent, 24 gm) and maltodextrin (14.2 dextrose equivalent, 28 gm) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 1,76,597 Da

About 50 percent of the volume was distilled from the above solution under vacuum to obtain iron carboxymaltose complex.

Iron content = 50 mg/ml

Example 5

Example 2 was repeated using maltodextrin (16 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 2,50,800 Da

Iron content = 24 mg/gm

Example 6

To a mixture of ferric hydroxide (as prepared in example 1 from 61.5 gm of ferric chloride) and water (100 ml) was added maltodextrin (50 gm, 14.2 dextrose equivalent) in water (100 ml). The pH was adjusted to 11 with dilute sodium hydroxide solution and then added sodium hypochlorite solution (70 gm) containing 3.1 gm of active chlorine and sodium bromide (0.5 gm) at ambient temperature. The reaction mixture pH was adjusted to 11 and stirred for 1 hour at ambient temperature. The mixture was heated to 50°C and maintained for 30 minutes and then the pH was adjusted to 6 with diluted hydrochloric acid and maintained for 30 minutes at 50°C. The reaction mass was heated to 96 to 98°C and maintained for 1 hour. The solution was cooled to ambient temperature to obtain iron carboxymaltose complex.

Molecular Weight = 2,78,000 Da Example 6a

The iron carboxymaltose complex as obtained in example 6 was precipitated by using ethanol ; Added iron carboxymaltose solution (50 gm) obtained above to ethanol (1400 ml) and stirred for 3 hours at ambient temperature. The solid obtained was collected by filtration, washed with ethanol and the solid dried at 50°C under vacuum for 2 hours to obtain iron carboxymaltose powder.

Molecular Weight = 2,73,0000 Da

Iron content = 22% W/W

Example 7

Example 6 was repeated using maltodextrin (6 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 3,10,000 Da

Iron content = 25 mg/gm

Example 8

Example 6 was repeated using a mixture of maltodextrin (6 dextrose equivalent, 24 gm) and maltodextrin (14.2 dextrose equivalent, 28 gm) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 1,380,000 Da

About 50 percent of the volume was distilled from the above solution under vacuum to obtain iron carboxymaltose complex.

Iron content = 50 mg/ml

Example 9

Example 6 was repeated using maltodextrin (16 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex. Molecular Weight

Iron content

Example 10

To a mixture of ferric hydroxide (as prepared in example 1 from 61.5 gm of ferric chloride) in water (100 ml) was added maltodextrin (50 gm, 14.2 dextrose equivalent) in water (100 ml). The pH was adjusted to 11 with dilute sodium hydroxide solution. To this mixture was added sodium hypochlorite solution (70 gm) containing 3.1 gm of active chlorine and sodium bromide (0.5 gm). The reaction mixture pH was adjusted to 11 and stirred for 1 hour at ambient temperature. The mixture was heated to 50°C and maintained for 30 minutes and then the pH was adjusted to 6 with dilute hydrochloric acid and maintained for 30 minutes. The mixture was taken in autoclave and maintained for 1 hour at 121°C and 1.1 kg/cm ² pressure. The solution was cooled to ambient temperature to obtain iron carboxymaltose complex.

Molecular Weight = 2,28,000 Da

The above solution was precipitated by using ethanol. Added iron carboxymaltose solution (50 gm) obtained above to ethanol (1400 ml) and stirred for 3 hours at ambient temperature. The solid obtained was collected by filtration, washed with ethanol and the solid dried at 50°C under vacuum for 2 hours to obtain iron carboxymaltose powder.

Molecular Weight = 2,25,000 Da

Iron content = 21% W/W

Example 11

Example 10 was repeated using maltodextrin (6 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 2,80,000 Da

Iron content = 22.3 mg/gm

Example 12 Example 10 was repeated using a mixture of maltodextrin (6 dextrose equivalent, 24 gm) and maltodextrin (14.2 dextrose equivalent, 28 gm) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight - = ■ 2,41,172 Da

Iron content = 23 mg/gm

Example 13

Example 10 was repeated using maltodextrin (16 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular Weight = 3,10,000 Da

Iron content = 24.5 mg/gm

Example 14

To a mixture of ferric hydroxide (as prepared in example 1 from 61.5 gm of ferric chloride) and water (100 ml) and was added maltodextrin (50 gm, 14.2 dextrose equivalent) in water (100 ml) and then the pH was adjusted to 11 with dilute sodium hydroxide solution. The reaction mixture was heated to 90°C and maintained for 30 minutes at 90°C. The solution was cooled to ambient temperature to obtain iron maltodextrin complex (Molecular weight : 2,40,000 Da).

To iron (III) maltodextrin complex was added sodium hypochlorite solution (70 gm) containing 3.1 gm of active chlorine and sodium bromide (0.5 gm) and then the pH was adjusted to 11. The solution was maintained for 1 hour at ambient temperature and heated to 50°C, maintained for 30 minutes. The pH was adjusted to 6 with dilute hydrochloric acid and maintained for 30 minutes at 50°C. The reaction mass was heated to 96 to 98°C and maintained for 30 minutes. The solution was cooled to ambient temperature to obtain iron carboxymaltose complex.

Molecular Weight = 1,90,000 Da Example 14a

The iron carboxymaltose complex as obtained in example 14 was precipitated by using ethanol. Added iron carboxymaltose solution (50 gm) obtained above to ethanol (1400 ml) -and stirred for 3 hours at ambient - temperature. The solid obtained was collected by filtration, washed with ethanol and the solid dried at 50°C under vacuum for 2 hours to obtain iron carboxymaltose powder.

Molecular Weight = 1,88,000 Da

Iron content = 20% W/W

Example 15

Example 14 was repeated using maltodextrin (6 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Iron maltodextrin complex molecular weight = 5,53,240 Da

Iron carboxymaltose complex molecular weight = 3,40,000 Da

Iron content = 24.8 mg/gm

Example 16

Example 14 was repeated using a mixture of maltodextrin (6 dextrose equivalent, 24 gm) and maltodextrin (14.2 dextrose equivalent, 28 gm) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex. Iron maltodextrin complex molecular weight = 2,55,569 Da

Iron carboxymaltose complex molecular weight = 2,39,612 Da

About 50 percent of the volume was distilled from the above solution under vacuum to obtain iron carboxymaltose complex.

Iron content = 50 mg/ml

Example 17 Example 14 was repeated using maltodextrin (16 dextrose equivalent) instead of maltodextrin (14.2 dextrose equivalent) to obtain iron carboxymaltose complex.

Molecular -Weight ■=· 3,70,000 Da

Iron content = 23 mg/gm