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|Title:||Process for preparing mucopolysaccharide compositions having high antithrombotic activity, the compositions obtained and their use as medicaments|
|Abstract:||The invention relates to a process for preparing mucopolysaccharides having high anti-thrombotic activity compared to heparin. The mucopolysaccharides are obtained from a mucopolysaccharide composition having high anti-thrombotic activity and a ratio of YW/USP Titer higher than that of heparin by fractionation to remove, selectively, the mucopolysaccharide chains having less than six saccharide units.|
|Inventor(s):||Lormeau; Jean-Claude (Maromme, FR), Choay; Jean (Paris, FR)|
|Assignee:||D.R.O.P.I.C. (Paris, FR)|
|Filing Date:||Dec 13, 1984|
|Claims:||1. A process for the preparation of mucopolysaccharides having higher antithrombic activity and a lower ratio of YW/USP and lower YW titer than the starting mucopolysaccharides, which process comprises treating mucopolysaccharide fractions, having a high antithrombic activity and a ratio of YW/USP titers higher than that of heparin and having mucopolysaccharide chains which contain less than about 6 units with an acidic aqueous mixture which contains an inorganic salt and an organic solvent in which solvent the inorganic salt is miscible and in which aqueous mixture mucopolysaccharides which have chains of 6 units and greater are insoluble and recovering mucopolysaccharides free of mucopolysaccharide chains of less than 6 units, thereby having performed a fractionation of the starting mucopolysaccharides having an average higher molecular weight. |
2. The process of claim 1 wherein the mucopolysaccharides have a 2,5-anhydromanno-terminal structure at the reducing end.
3. The process of claim 2 wherein the 2,5-anhydromannose structure is selected from the group consisting of 2,5-anhydromannose, 2,5-anhydromannitol and 2,5-anhydromannonic acid.
4. The process of claim 1 wherein the organic solvent is an alcoholic solvent.
5. The process of claim 4 wherein the alcoholic solvent is ethanol.
6. The process of claim 1 wherein the inorganic salt is a salt miscible in the organic solvent.
7. The process of claim 1 wherein the inorganic salt is selected from the group consisting of sodium chloride and potassium chloride.
8. The process of claim 1 wherein the aqueous mixture is acidic to below a pH of 4.
9. The process of claim 8 which comprises dissolving the starting mucopolysaccharides in water, adding the inorganic salt, lowering the pH to an acidic pH and adding the organic solvent to said aqueous mixture.
10. The process of claim 9 wherein there is dissolved about 5% per weight of mucopolysaccharides in water containing 10 g/l of ethanol, adjusting the pH to about 3.8 and recovering the precipitate.
11. The process of claim 1 wherein the starting mucopolysaccharides have a ratio of YW to USP titers of at least about 10 and a YW titer of about 200 to 250 u/mg.
12. The process of claim 1 wherein the organic solvent causes the precipitation of the mucopolysaccharides which have a ratio of YW to USP titers less than 6.
13. The process of claim 9 wherein after the addition of the organic solvent, a precipitate is formed, which is recovered.
14. The process of claim 13 wherein the inorganic salt is sodium chloride and the organic solvent is ethanol.
15. The process of claim 13 which comprises washing the recovered precipitate.
16. A process for the preparation of mucopolysaccharides having YW and USP titers in a ratio of about 6 to 3, and a YW titer higher than that of heparin, of at least 180-200 u, comprises
using an heparin aqueous solution, said heparin having a YW/YSP ratio of about 1, the YW and USP titers being respectively of about 160-170,
lowering the pH to 2.5,
adding an aqueous solution of sodium nitrite, sodium nitrite being used in an amount of 15 g dissolved in 300 ml of water when using a solution of heparin containing 500 g of heparin, in the form of sodium salt, in solution in 4500 ml of water,
adjusting the pH to 2.5,
ajusting the reaction volume, the total volume being brought to 5000 ml when using said concentrations of reactants,
allowing the reaction to take place up to the total disappearance of nitrous acid,
raising to 10 the pH of the solution,
eliminating the unreacted sodium tetrahydroborate and adjusting the pH to 7.0,
adding 10 l of ethanol and recovering the insoluble products,
redissolving the precipitate in 9 l of water,
adding sodium chloride in a proportion of 100 g in view of the above concentration,
lowering the pH to 3.8,
adjusting the final volume to 10 liters,
adding 10 liters of ethanol,
precipitating a solid and recovering the solid.
17. The process of claim 11 wherein the ratio of YW to USP is about 4.