Chitosan derivatives in the form of coordinated complexes with ferrous ions

Claim 2

Chitosan derivatives in the form of coordinated complexes with ferrous ions comprising chitosans of the 6-0-sulphate type (I) in which n varies from 250 to 2300, in the form of complexes in which coordinate bonds are established between Fe ++ and the amino group and hydroxyl group present respectively in position 2 and position 3 of the chitosan glucosamide ring.

Claim 3

A process for preparing chitosan derivatives in the form of coordinated complexes with ferrous ions comprising chitosans of the 6-0-sulphate type (I) in which n varies from 250 to 2300, in the form of complexes in which coordinate bonds are established between Fe ++ and the amino group and hydroxyl group present respectively in position 2 and position 3 of the chitosan glucosamide ring, characterised by being conducted in the following stages: a) dissolving the chitosan (II) in an organic acid; b) adding a ferrous sulpate solution to precipitate the coordinated complex; c) filtering, washing and drying the precipitated complex; d) sulphating the dried complex by means of an SO 3 -organic base complex, followed by treatment with a strong inorganic base.

Claim 4

A process for preparing chitosan derivatives in the form of coordinated complexes with ferrous ions comprising chitosans of the 6-0-sulphate type (I) in which n varies from 250 to 2300, in the form of complexes in which coordinate bonds are established between Fe ++ and the amino group and hydroxyl group present respectively in position 2 and position 3 of the chitosan glucosamide ring, characterised by being conducted in the following stages: a) dissolving the chitosan (II) in an organic acid; b) adding a ferrous sulpate solution to precipitate the coordinated complex; c) filtering, washing and drying the precipitated complex; d) sulphating the dried complex by means of an SO 3 -organic base complex, followed by treatment with a strong inorganic base.

Claim 5

A process as claimed in claim 2, characterised in that the chitosan is dissolved in acetic or formic acid of concentration between 1 and 5% by volume, at ambient temperature.

Claim 6

A process as claimed in claim 2, characterised in that the ferrous sulphate is added in the form of a ferrous sulphate solution of concentration between 200 and 600 g/l, operating at a pH of between 2 and 7 and at a temperature of between 5 and 25°C.

Claim 7

A process as claimed in claim 2, characterised in that the weight ratio of the chitosan to the added FeS0 4 is between 1 and 5.

Claim 8

6 A process as claimed in claim 2, characterised in that the dried complex is sulphated by using as sulphating agent a complex of sulphur trioxide with a weak base such as pyridine, trimethylamine, triethylamine or dimethylformamide, in a reaction medium consisting of anhydrous dimethylformamide.

Claim 9

A process as claimed in claim 2, characterised in that the dried complex is sulphated by using as sulphating agent a complex of chlorosulphonic acid with formamide or with dimethylformamide.

Claim 10

Pharmaceutical compositions containing chitosan derivatives in the form of coordinated complexes with ferrous ions as defined and prepared in accordance with claims 1 to 7.