LOW MOLECULAR WEIGHT HEPARINS INCLUDING AT LEAST ONE COVALENT BOND WITH BIOTIN OR A BIOTIN DERIVATIVE, METHOD FOR MAKING SAME AND USE THEREOF
The invention relates to biotinylated low molecular weight heparins comprising constituent polysaccharides having at their reducing ends at least one covalent bond with biotin or a biotin derivative, and also to the process for preparing them, to pharmaceutical compositions containing them and to their therapeutic use.
1 . A biotinylated low molecular weight heparin, comprising constituent polysaccharides having an average molecular weight of between 3000 and 7000 Da, wherein the constituent polysaccharides are covalently bonded to biotin or a biotin derivative at their reducing ends, or the pharmaceutically acceptable salts thereof.
2 . The biotinylated low molecular weight heparin according to claim 1 , wherein the covalently bonded constituent polysaccharides correspond to the formula (I):
in which:
i is equal to 0 or 1,
R1 represents a sequence of formula (a) or (b):
in which j and k, which may be identical or different, are integers that may take any value from 1 to 10,
Biot represents a biotin group or a biotin derivative,
PE represents a polysaccharide chain having the general structure of the constituent polysaccharides of heparin,
X represents H or SO 3 Na,
Y represents SO 3 Na or COCH 3 , and
the wavy line denotes a bond located either below or above the plane of the pyranose ring to which it is attached.
3 . The biotinylated low molecular weight heparin according to claim 2 , wherein i is equal to 0.
4 . The biotinylated low molecular weight heparin according to claim 2 , wherein i is equal to 1 and R1 represents a sequence of formula (a) in which j is equal to 5.
5 . The biotinylated low molecular weight heparin according to claim 2 , wherein i is equal to 1 and R1 represents a sequence of formula (b) in which j and k are identical and are equal to 5.
6 . The biotinylated low molecular weight heparin according to claim 2 , wherein Biot represents the biotin group of formula (c):
7 . The biotinylated low molecular weight heparin according to claim 1 , wherein at least 60% of the constituent polysaccharides have at their reducing ends a covalent bond to biotin or a biotin derivative.
8 . The biotinylated low molecular weight heparin according to claim 7 , wherein at least 80% of the constituent polysaccharides have at their reducing ends a covalent bond to biotin or a biotin derivative.
9 . The biotinylated low molecular weight heparin according to claim 8 , wherein at least 90% of the constituent polysaccharides have at their reducing ends a covalent bond to biotin or a biotin derivative.
10 . The biotinylated low molecular weight heparin according to claim 1 , wherein the low molecular weight heparin is chosen from enoxaparin, ardeparin, bemiparin, parnaparin and tinzaparin.
11 . The biotinylated low molecular weight heparin according to claim 1 , wherein the low molecular weight heparin is such that:
from 9% to 20% of its constituent polysaccharides have an average molecular weight of less than 2000 Da,
from 5% to 20% of its constituent polysaccharides have an average molecular weight of greater than 8000 Da,
from 60% to 86% of its constituent polysaccharides have an average molecular weight of between 2000 and 8000 Da,
the ratio between the mass-average molecular mass and the number-average molecular mass is between 1.3 and 1.6, and
the low molecular weight heparin has better bioavailability and antithrombotic activity than that of heparin and has an average molecular weight of approximately between 3500 and 5500 Da.
12 . A process for preparing the biotinylated low molecular weight heparin as defined in claim 2 , the process comprising the following steps:
a) performing a reductive amination on a low molecular weight heparin, in the presence of an amine salt and a reducing agent, at a temperature of between 20 and 80° C.; and
b) then performing an acylation with an activated group —(R1) i -Biot, in which R1, i and Biot are as defined in claim 2 , in the presence of a base, in aqueous medium or in organic medium.
13 . A process for preparing the biotinylated low molecular weight heparin as defined in claim 2 , the process comprising the following steps:
a) performing a reductive amination on a low molecular weight heparin, in the presence of an ammonium halide salt and a borohydride salt, at a temperature of between 50 and 80° C., and
b) then performing an acylation with a group —(R1) i -Biot in activated ester form, in the presence of a base in aqueous medium.
14 . A pharmaceutical composition comprising, as active principle, a biotinylated low molecular weight heparin according to claim 1 and at least one pharmaceutically acceptable excipient.
15 . A method for the treatment or prevention of thrombosis in a patient, the method comprising administering to the patient an antithrombotic effective amount of a biotinylated low molecular weight heparin according to claim 1 .
16 . The method according to claim 15 , wherein the biotinylated low molecular weight heparin is administered for treating and preventing venous thrombosis, arterial thrombotic accidents, peripheral arterial thrombosis, cerebral arterial thrombosis or strokes, the proliferation of smooth muscle cells, or angiogenesis, or as a neuroprotective agent for atherosclerosis and arteriosclerosis.
17 . The method according to claim 16 wherein the arterial thrombotic accidents involve myocardial infarction or unstable angina, and the peripheral arterial thrombosis involves arteriopathy of the lower limbs.
18 . A method for neutralizing the biotinylated low molecular weight heparin according to claim 1 , the method comprising using a neutralizing amount of avidin or streptavidin
19 . The method according to claim 15 further comprising administering avidin or streptavidin to neutralize the antithrombotic effect of the biotinylated low molecular weight heparin.