Orally administrable pharmaceutical iron preparation

Claim 1

AN ORALLY ADMINISTRABLE PHARMACEUTICAL IRON PREPARATION HAVING A GRADUALLY IRON-RELEASING ACIVITY WHICH CONSISTING ESSENTIALLY OF AN IRON SALT OF A WATER-SOLUBLE LINEAR POLYMER CONTAINING FROM 2 TO 16 MILLIMOLES OF CARBOXYLIC GROUPS PER GRAM OF THE POLYMER, SAID SALT CONTAINING BOUND IRON IN AN AMOUNT OF FROM ABOUT 2.5 TO ABOUT 33% BY WEIGHT BASED ON THE WEIGHT OF THE SALT, SAID POLYMER BEING SELECTED FROM THE GROUP CONSISTING OF (1) A POLYMER OF AT LEAST ONE UNSATURATED MONOMER SELECTED FROM THE GROUP CONSISTING OF ACRYLIC ACID AND METHACRYLIC ACID, (2) A COPOLYMER OF MALEIC ACID WITH AT LEAST ONE VINYL COMPOUND SELECTED FROM THE GROUP CONSISTING OF VINYL ACETATE, A LOWER ALKYL VINYL ETHER, ACRYLIC ACID A LOWER ALKYL ESTER OF ACRYLIC ACID, METHACRYLIC ACID, A LOWER ALKYL ESTER OF METHACRYLIC ACID AND VINYL ALCOHOL, AND (3) A COPOLYMER OF VINYL ALCOHOL WITH AN UNSATURATED MONOMER SELECTED FROM THE GROUP CONSISTING OF ACRYLIC ACID AND METHACRYLIC ACID, AND AT LEAST 50% BY WEIGHT OF SAID BOUND IRON BEING BIVALENT.

Claim 6

A method of preparing an orally administrable iron salt having a sustained iron-releasing activity and being free of a resin Insoluble in gastric juice or intestinal fluid, which comprises mixing in an aqueous medium a water-soluble inorganic iron salt with a water-soluble linear polymer containing 2 to 16 millimoles of carboxylic groups, said polymer being selected from the group consisting of (1) a polymer of at least one unsaturated monomer selected from the group consisting of acrylic acid and methacrylic acid, (2) a copolymer of maleic acid with at least one vinyl compound selected from the group consisting of vinyl acetate, a lower alkyl vinyl ether, acrylic acid, a lower alkyl ester of acrylic acid, methacrylic acid, a lower alkyl ester of methacrylic acid and vinyl alcohol, and (3) a copolymer of vinyl alcohol with an unsaturated monomer selected from the group consisting of acrylic acid and methacrylic acid, and thereafter separating the resulting iron salt of said linear polymer as a solid by a procedure selected from: a. maintaining the pH of the resulting mixture at 5.0-8.0, b. evaporating to dryness the resulting mixture after removing foreign anions by means of an anion exchange resin, c. adding a water-miscible organic solvent to the resulting mixture after removing foreign anions by means of an anion exchange resin,, d. salting out the resulting mixture after removing foreign anions by means of an anion exchange resin, e. or a combination of two or more of the above.

Claim 7

A method of preparing an orally administrable iron salt having a sustained iron-releasing activity and being free of a resin Insoluble in gastric juice or intestinal fluid, which comprises mixing in an aqueous medium a water-soluble inorganic iron salt with a water-soluble linear polymer containing 2 to 16 millimoles of carboxylic groups, said polymer being selected from the group consisting of (1) a polymer of at least one unsaturated monomer selected from the group consisting of acrylic acid and methacrylic acid, (2) a copolymer of maleic acid with at least one vinyl compound selected from the group consisting of vinyl acetate, a lower alkyl vinyl ether, acrylic acid, a lower alkyl ester of acrylic acid, methacrylic acid, a lower alkyl ester of methacrylic acid and vinyl alcohol, and (3) a copolymer of vinyl alcohol with an unsaturated monomer selected from the group consisting of acrylic acid and methacrylic acid, and thereafter separating the resulting iron salt of said linear polymer as a solid by a procedure selected from: a. maintaining the pH of the resulting mixture at 5.0-8.0, b. evaporating to dryness the resulting mixture after removing foreign anions by means of an anion exchange resin, c. adding a water-miscible organic solvent to the resulting mixture after removing foreign anions by means of an anion exchange resin,, d. salting out the resulting mixture after removing foreign anions by means of an anion exchange resin, e. or a combination of two or more of the above.