PROCESS FOR THE PREPARATION OF FERRIC CITRATE
Method are provided for obtaining ferric citrate that includes the step(s) of reacting ferric chloride with a suitable base to obtain ferric hydroxide; reacting the ferric hydroxide with citric acid to obtain ferric citrate; and processing the ferric citrate to obtain ferric citrate. The resulting ferric citrate has a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g.
1 . A method for obtaining ferric citrate comprising:
reacting ferric chloride with a suitable base to obtain ferric hydroxide;
reacting the ferric hydroxide with citric acid to obtain ferric citrate; and
processing the ferric citrate to obtain ferric citrate having a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g.
2 . The method of claim 1 , wherein the ferric chloride is reacted with a suitable base in the presence of water, and wherein the suitable base comprises one or more of: sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, caesium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.
3 . The method of claim 1 , wherein the ferric chloride is ferric chloride formula IV.
4 . The method of claim 1 , wherein the ferric hydroxide is ferric hydroxide formula III.
5 . The method of claim 1 , wherein the citric acid is citric acid formula II.
6 . The method of claim 1 , wherein the ferric citrate is ferric citrate formula I.
7 . The method of claim 1 , wherein the ferric citrate obtained is in liquid form.
8 . The method of claim 7 , wherein processing the ferric citrate comprises filtering the liquid ferric citrate to obtain liquid filtrate ml of ferric citrate.
9 . The method of claim 7 , comprising isolating ferric citrate from the liquid filtrate ml of ferric citrate.
10 . The method of claim 9 , wherein isolating ferric citrate comprises adding a suitable solvent to the liquid filtrate ml of ferric citrate, slurring resulting solid material in the solvent, and drying the solid material.
11 . The method of claim 10 , wherein isolating ferric citrate further comprises passing dried ferric citrate through a sieve to obtain ferric citrate powder having surface area greater than 20 sq. m/g.
12 . The method of claim 11 , wherein isolating the ferric citrate further comprises spraying the ferric citrate powder with water, blending the mixture, drying the mixture, and passing the dried mixture through a sieve to obtain the ferric citrate having a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g.
13 . The method of claim 11 , wherein isolating the ferric citrate further comprises charging the dried ferric citrate into a solvent, blending, the mixture, drying the mixture, and passing the dried mixture through a sieve to obtain the ferric citrate having a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g.
14 . The method of claim 11 , wherein isolating the ferric citrate further comprises charging the ferric citrate powder with a solvent, stirring the reaction mass, and washing the reaction mass with the solvent.
15 . The method of claim 14 , wherein the solvent comprises at least one of: acetone, methanol, isopropyl alcohol and tetrahydrofuran.
16 . The method of claim 11 , wherein isolating the ferric citrate further comprises dividing the liquid filtrate ml of ferric citrate into at least two equal lots; charging each lot of filtrate with a suitable solvent, mixing each lot, creating a slurry comprising the at least two lots, drying the combined lots, and passing the dried combination through a sieve to obtain the ferric citrate having a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g.
17 . The method of claim 16 , wherein the suitable solvent comprises at least one of acetone, methanol, ethanol or isopropyl alcohol, tetrahydrofuran, Acetonitrile, and 1,4-Dioxane.
18 . A pharmaceutical formulation comprising the ferric citrate having a specific surface area greater than 16 sq. m/g, but less than 20 sq. m/g. obtained using the method of claim 1 .