Carboxylated derivatives of glycosaminoglycans and use as drugs
The invention relates to glycosaminoglycan derivatives, endowed with heparanase inhibitory activity and antitumor activity, bearing carboxylate groups in positions 2 and 3 of at least part of the glycosaminoglycan residues, and to the process for preparing the same. The glycosaminoglycan derivatives of the present invention are generated starting from natural or synthetic glycosaminoglycans, preferably heparin or low molecular weight heparin, optionally 2-O- and 2N-desulfated by two steps of oxidation. By the first oxidation, adjacent diols and optionally adjacent OH/NH 2 of the glycosaminoglycan residues are converted to aldehydes and by the second oxidation said dialdehydes are converted to carboxylate groups. The first oxidation preferably leads to the cleavage of C 2 -C 3 linkage of the ring of oxidable residues. The invention further relates to a process for the preparation of said glycosaminoglycan derivatives and further to their use as active ingredients of medicaments. Furthermore, the invention relates to pharmaceutical compositions comprising di/tricarboxylated heparin derivatives, as active agent.
1. A process for the preparation of a glycosaminoglycan derivative inhibiting heparanase comprising:
a) oxidation of 10% to 100%, of 2-O-non-sulfated residues of a glycosaminoglycan, under conditions effective to convert adjacent diols to dialdehydes, wherein the oxidation is performed at pH 3-5 in the air;
b) oxidation of the oxidized glycosaminoglycan under conditions effective to convert said dialdehydes to carboxylate groups;
wherein the glycosaminoglycan is selected from heparin, heparan sulfate, optionally 2-O- and/or 2-N-desulfate;
wherein the oxidation in step a) is performed by periodate;
the glycosaminoglycan has a sulfation degree (SO 3 − /COO − ), determined by conductimetric titration as defined herein, of from 0.9 to 2.5;
and
the glycosaminoglycan derivative has a carboxyl increment as defined herein, of from 1.2 to 2.2.
2. The process of claim 1 wherein in step a) from 25% to 100%, of 2-O-non-sulfated residues of a glycosaminoglycan are oxidized.
3. The process of claim 1 , wherein the glycosaminoglycan is selected from unfractionated heparin or LMWH, optionally 2-O- and/or 2-N-desulfated.
4. A process for the preparation of a glycosaminoglycan derivative inhibiting heparanase comprising:
a) oxidation of 10% to 100%, of 2-O-; and 2N-, 3-O-, non-sulfated residues of a glycosaminoglycan, under conditions effective to convert adjacent diols and adjacent OH/NH2 to dialdehydes, wherein the oxidation is performed at pH 5.5-10 in the air;
b) oxidation of the oxidized glycosaminoglycan under conditions effective to convert said dialdehydes to carboxylate groups;
wherein the glycosaminoglycan is selected from heparin, heparan sulfate, optionally 2-O- and/or 2-N- desulfated;
the glycosaminoglycan has a sulfation degree (SO 3 − /COO − ), determined by from 1.2 to 2.2.
5. The process of claim 4 , wherein in step a) from 25% to 100%, of 2-O-, and 2N-, 3-O-, non-sulfated residues of a glycosaminoglycan are oxidized.
6. The process of claim 4 , wherein the glycosaminoglycan is selected from unfractionated heparin or LMWH, optionally 2-O- and/or 2-N-desulfated.