Low molecular weight heparins of regular structure, their preparation and their biological uses.
AssigneeSanofi
InventorsJean-Claude Lormeau, Maurice Petitou, Jean Choay
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Abstract
The compositions of the invention are composed of fragments of heparin consisting essentially of repeated disaccharide sequences corresponding to the regular regions of heparin and possessing a MW between 4,800 and 9,000. These compositions can be used for the regulation of physiological systems.
Claims18
A composition of heparins of low molecular weight and their pharmaceutically acceptable salts, which composition is almost completely lacking anticoagulant activity and essentially consists of fragments lacking repeating disaccharide sequences of non-sulfated uronic acid glucosamine N-sulfate, the fragments having the following general Formula I:
- R--(X--Y).sub.n --R (I)
- in which
- (a) X is selected from the group consisting of a sulfated iduronic acid residue of Formula II:
- ##STR6## and a non-sulfated uronic acid residue which is selected from the group consisting of D-glucuronic acid and L-iduronic acid and which is ring-opened between the carbon atoms at positions 2 and 3 of Formula III:
- ##STR7## wherein X is the non-sulfated uronic acid residue to the extent of at least about one residue per every two fragments;
- (b) Y is a D-glucosamine residue of Formula IV:
- ##STR8## wherein R.sub.1 is selected from the group consisting of a hydrogen atom and a --SO.sub.3 -- group, R.sub.2 is selected from the group consisting of a --SO.sub.3 -- group and a --CO--CH.sub.3 group wherein R2 is a --SO.sub.3 -- group for at least 90% of all occurrences of R.sub.2 in the composition, R.sub.3 is selected from the group consisting of a --SO.sub.3 -- group and a hydrogen atom, wherein R.sub.3 is a --SO.sub.3 -- group for at least 70% of all occurrences of R.sub.3 in the composition;
- (c) R is selected from the group consisting of a hydrogen atom and a residue:
- ##STR9## wherein R.sub.1 and R.sub.2 and R.sub.3 are as defined above, and R4 is selected from the group consisting of a hydrogen atom and a uronic acid residue;
- (d) R' is selected from the group consisting of a hydrogen atom, an unmodified uronic acid residue, and a modified uronic acid residue containing aldehyde groups resulting from the cleavage of the bond between the carbon atoms C2 and C3 of uronic acid during the course of periodic oxidation and the aldehyde functions of which have been reduced to alcohols;
- and
- (e) 7.ltoreq.n.ltoreq.15 for the majority of the fragments.
A process for the preparation of compositions of heparins of low MW which comprises the steps of:
- (a) treating an aqueous solution of heparin at a final concentration of 0.5 to 5% (wt/v) with periodic acid at a final concentration of 0.5 to 4% (wt/v) at a pH between 4.5 and 6.5 and at a temperature between 0.degree. and 10.degree. C.;
- (b) depolymerizing chains of heparin thus obtained with a strong base at a final molarity of the base of 0.1 to 0.3N;
- (c) treating depolymerization fragments thus obtained with a reducing agent, removing excess reducing agent when it is in excess;
- (d) precipitating reduced fragments obtained in a solvent in which the fragments are insoluble;
- (e) redissolving the precipitate to form an aqueous solution;
- (f) treating the aqueous solution, to which a mineral salt has been added with alcohol in order to fractionate and remove low molecular weight fragments;
- (g) recovering the fragments in the form of a salt with a strong base and converting the salt corresponding to the strong base into a pharmaceutically acceptable salt.
Dependencies are inferred from the claim text.