U.S. patent application number 16/823068 was filed with the patent office on 2021-10-28 for derivatives of n-desulfated glycosaminoglycans and use as drugs.
The applicant listed for this patent is Novahealth Biosystems, LLC. Invention is credited to Annamaria Naggi, Giangiacomo Torri.
Application Number | 20210332162 16/823068 |
Document ID | / |
Family ID | 1000005895420 |
Filed Date | 2021-10-28 |
United States Patent
Application |
20210332162 |
Kind Code |
A9 |
Torri; Giangiacomo ; et
al. |
October 28, 2021 |
DERIVATIVES OF N-DESULFATED GLYCOSAMINOGLYCANS AND USE AS DRUGS
Abstract
A glycosaminoglycan derivative which is obtainable by a process
that includes the steps of N-desulfation of from 25% to 100% of the
N-sulfated residues of a glycosaminoglycan, and oxidation, by
periodate at a pH of from 5.5 to 10.0, of from 25% to 100% of the
2-N-, 3-O-non-sulfated glucosamine residues, and of the
2-O-non-sulfated uronic acid residues of said glycosaminoglycan,
under conditions effective to convert adjacent diols and adjacent
OH/NH.sub.2 to aldehydes. The process further includes reduction,
by sodium borohydride, of said oxidized glycosaminoglycan, under
conditions effective to convert said aldehydes to alcohols, where
the glycosaminoglycan is heparin, low molecular weight heparin,
heparan sulfate or fractions thereof.
Inventors: |
Torri; Giangiacomo; (Milano,
IT) ; Naggi; Annamaria; (Legnano, IT) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Novahealth Biosystems, LLC |
Waunakee |
WI |
US |
|
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Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20200216577 A1 |
|
|
US 20210054108 A2 |
February 25, 2021 |
|
|
Family ID: |
1000005895420 |
Appl. No.: |
16/823068 |
Filed: |
March 18, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15032248 |
Apr 26, 2016 |
10875936 |
|
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PCT/EP2014/072707 |
Oct 23, 2014 |
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16823068 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08B 37/0075 20130101;
C08B 37/0072 20130101; C08B 37/0069 20130101; A61K 31/737 20130101;
C08B 37/0078 20130101; A61K 31/727 20130101; C08B 37/0063 20130101;
A61K 31/728 20130101; A61K 31/726 20130101 |
International
Class: |
C08B 37/00 20060101
C08B037/00; A61K 31/727 20060101 A61K031/727; A61K 31/726 20060101
A61K031/726; A61K 31/728 20060101 A61K031/728; A61K 31/737 20060101
A61K031/737; C08B 37/08 20060101 C08B037/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2013 |
IT |
LO2013A000005 |
Claims
1. A glycosaminoglycan derivative which is obtainable by the
following process: a) N-desulfation of from 25% to 100% of the
N-sulfated residues of a glycosaminoglycan; b) oxidation, by
periodate at a pH of from 5.5 to 10.0, of from 25% to 100% of the
2-N-, 3-O-non-sulfated glucosamine residues, and of the
2-O-non-sulfated uronic acid residues of said glycosaminoglycan,
under conditions effective to convert adjacent diols and adjacent
OH/NH.sub.2 to aldehydes; c) reduction, by sodium borohydride, of
said oxidized glycosaminoglycan, under conditions effective to
convert said aldehydes to alcohols; wherein the glycosaminoglycan
is heparin, low molecular weight heparin, heparan sulfate or
fractions thereof.
2. The glycosaminoglycan derivative of claim 1, wherein the process
further comprising: d) 2-O-desulfation of up to 50% of the
2-O-sulfated residues of the glycosaminoglycan, before or after
N-desulfation.
3. The glycosaminoglycan derivative of claim 2, wherein said d)
2-O-desulfation of up to 25% of the 2-O-sulfated residues of the
glycosaminoglycan.
4. The glycosaminoglycan derivative of claim 1, wherein the process
further comprising: e) partial or total deacetylation of the
N-acetylated residues of the glycosaminoglycan, before or after
N-desulfation.
5. The glycosaminoglycan derivative of claim 1, wherein the
glycosaminoglycan derivative has a molecular weight of from 3,000
to 20,000 Da.
6. The glycosaminoglycan derivative of claim 1, wherein the
glycosaminoglycan derivative has a molecular weight of from 3,500
to 12,000 Da.
7. Oligosaccharides compound which is obtainable by enzymatic or
chemical partial depolymerization of the glycosaminoglycan
derivative of claim 1.
8. A method of treating tumor metastasis or tumor in a patient,
comprising administering to the patient in need of such treatment a
pharmaceutical composition comprising a therapeutically effective
amount of the glycosaminoglycan derivative of claim 1, or a
pharmaceutically acceptable salt thereof, and at least one
pharmaceutically acceptable carrier, excipient, or diluent.
9. The method of claim 8, wherein the tumor is myeloma.
10. A derivative of N-desulfated glycosaminoglycan characterized in
that said derivative comprises the following three structures:
##STR00001## wherein each R.sub.2 is SO.sub.3.sup.- or H; R.sub.3
is SO.sub.3.sup.- or H; R.sub.4 is SO.sub.3.sup.- or H; wherein the
starting glycosaminoglycan that the derivative of N-desulfated
glycosaminoglycan is derived from is selected from a natural or
synthetic glycosaminoglycan; wherein the natural or synthetic
glycosaminoglycan is heparin, low molecular weight heparin, heparan
sulfate or fractions thereof.
11. The derivative of N-desulfated glycosaminoglycan of claim 10
further comprises the following two structures: ##STR00002##
wherein each R.sub.2 is SO.sub.3.sup.- or H; wherein R.sub.3 is
SO.sub.3.sup.- or H.
12. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein said derivative has a molecular weight selected from (a)
3,000 to 20,000 Da, or (b) 3,500 to 12,000 Da.
13. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein the natural or synthetic glycosaminoglycan is
unfractionated heparin, or heparin having a molecular weight of
from 3,500 to 8,000 Da.
14. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein the percentage, over the total of glycosaminoglycan
residues, of glycol split residues (RO), in which adjacent diols
and OH/NH.sub.2 have been converted into the corresponding aldehyde
and then into the corresponding alcohols, is between 31% and
54%.
15. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein the percentage, over the total of glycosaminoglycan
residues, of 2-O-sulfated L-iduronic acid (IdoA2S) is between 29%
and 40%.
16. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein the percentage, over the total of glycosaminoglycan
residues, of N-acetyl D-glucosamine (GlcNAc) is between 6% and
30%.
17. The derivative of N-desulfated glycosaminoglycan of claim 10,
wherein the percentage, over the total of glycosaminoglycan
residues, of 2-NH.sub.2 glucosamine (GlcNH.sub.2) is between 4% and
13%.
18. Pharmaceutical composition comprising the derivative of
N-desulfated glycosaminoglycan of claim 10.
19. A method of treating tumor metastasis or tumor in a patient,
comprising administering to the patient in need of such treatment a
pharmaceutical composition comprising a therapeutically effective
amount of the glycosaminoglycan derivative of claim 10, or a
pharmaceutically acceptable salt thereof, and at least one
pharmaceutically acceptable carrier, excipient, or diluent.
20. The method of claim 19, wherein the tumor is myeloma.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application is a divisional of co-pending U.S.
patent application Ser. No. 15/032,248, filed on Apr. 26, 2016, and
claims the benefit of International Application No.
PCT/EP2014/072707, filed on Oct. 23, 2014, and of Italian
Application No. LO2013A000005, filed on Oct. 31, 2013, the entire
teachings and disclosures of which are incorporated herein by
reference thereto.
FIELD OF THE INVENTION
[0002] The invention relates to N-desulfated and optionally
2-O-desulfated glycosaminoglycan derivatives, wherein at least part
of the adjacent diols and OH/NH.sub.2 have been converted into the
corresponding aldehyde, which aldehydes have been then reduced to
the corresponding alcohol. These products are endowed with
heparanase inhibitory activity and anti-tumor activity. Said
glycosaminoglycan derivatives are obtained from natural or
synthetic glycosaminoglycan, preferably from unfractionated
heparin, low molecular weight heparins (LMWHs), heparan sulfate or
derivatives thereof. Natural glycosaminoglycans can be obtained
from any animal source (different animal species and organs can be
employed).
[0003] The invention further relates to the process for preparation
of the same and further to their use as active ingredients of
medicaments, useful in pathological conditions. In particular, said
pathological conditions comprise multiple myeloma and other cancers
(i.e. sarcomas, carcinomas, hematological malignancies), including
their metastatic form. The glycosaminoglycan derivatives of the
invention can be used as medicaments also in combination with other
therapies, either oncological therapies or not. Furthermore, the
invention relates to the use of said N-desulfated and optionally
2-O-desulfated glycosaminoglycan derivatives, preferably obtained
from heparins and low molecular weight heparins (LMWHs), in any
therapeutic indication gaining benefit from the inhibition of
heparanase (i.e. diabetic nephropathy, inflammatory bowel disease,
colitis, arthritis, psoriasis, sepsis, atherosclerosis), also in
combination with known established drugs or treatments.
[0004] The invention also relates to pharmaceutical compositions
containing as active ingredient at least one of said N-desulfated
and optionally O-desulfated glycosaminoglycan derivatives, wherein
at least part of the adjacent diols and OH/NH.sub.2 have been
converted into the corresponding aldehyde, followed by reduction to
the corresponding alcohol. Optionally the invention relates to
pharmaceutical compositions containing as active ingredient at
least one of said glycosaminoglycan derivatives in combination with
at least one other active ingredient, more preferably a therapeutic
compound. Preferably, said glycosaminoglycan derivatives are
heparin derivatives or low molecular weight heparins (LMWHs). Other
aspects, objectives and advantages of the invention will become
more apparent from the following detailed description when taken in
conjunction with the accompanying drawings.
BACKGROUND OF THE INVENTION
[0005] Multiple myeloma is the second most prevalent hematologic
malignancy and accounts for over 10% of all hematologic cancer in
Unites States, with around 20,000 new cases each year and mortality
higher than 50% (Graham-Rowe D., 2011, Multiple myeloma outlook.
Nature 480, s34-s35).
[0006] Over the last few years, promising therapies have been
developed, such as the administration of proteasome inhibitor
(Velcade), bisphosphonates, thalidomide and others. The
effectiveness of these agents is, at least in part, due to their
impact on the myeloma tumor microenvironment.
[0007] Although efficacy against myeloma has been shown by said
agents, there is need for new and improved drugs for treating
myeloma and other tumors.
[0008] Heparanase is an endo-.beta.-glucuronidase that cleaves the
heparan sulfate (HS) chains of proteoglycans (PG-HS), such as
syndecan-1, thereby releasing HS-bound growth factors.
[0009] In humans, there appears to be a single dominant functional
heparanase enzyme capable of cleaving HS. Heparanase is expressed
by many human tumors, where it significantly increases both the
angiogenic and the metastatic potential of tumor cells. Elevated
heparanase levels have been in fact correlated with advanced
progression and metastasis of many tumor types. For example, high
level of heparanase is associated with a shorter post-operative
survival time of patients. A direct role of heparanase in tumor
metastasis has been demonstrated in Profs. Vlodaysky's and
Sanderson's laboratories, where our novel inhibitors have been
tested.
[0010] In addition to its enzymatic functions, that include release
of HS-bound growth factors and degradation of the extracellular
matrix (ECM) by invasive cells, heparanase has also a non-enzymatic
function that may impact tumor behavior and its microenvironment.
Sanderson's group pioneered the study of heparanase and syndecan-1
in myeloma, establishing that heparanase acts as a master regulator
of its aggressive tumor phenotype. This occurs by promoting the
up-regulation of VEGF and MMP-9, that together stimulate tumor
growth, metastatic and osteolytic bone destruction. It was in fact
demonstrated in vivo that heparanase promotes the growth of myeloma
tumors and spontaneous metastasis to bone and that heparanase
expression by tumor cells fuels rampant osteolysis, at least
partially due to up-regulation of RANKL expression. The osteolysis
promoting effect of heparanase may be of great importance because
bone-bound growth factors are released when bone is degraded. In
addition, osteoclasts can release tumor growth promoting factors,
such as HGF. Together these factors may help establish niches
within the bone marrow that support tumor cell homing and
subsequent growth (Fux, L., et al. 2009, Heparanase: busy at the
cell surface, Trends Biochem Sci 34 (10): 511-519; Sanderson, R.
D., and Yang, Y., 2008, Syndecan-1: a dynamic regulator of the
myeloma microenvironment, Clin. Exp Metastasis 25: 149-59; Ilan N.,
et al. 2006. Regulation, function and clinical significance of
heparanase in cancer metastasis and angiogenesis, Int. J. Biochem.
Cell Biol. 38: 2018-2039). Inhibition of heparanase is thus a
feasible target of myeloma therapy, supported by the fact that
there is a single enzymatically active heparanase and by the fact
that its expression in normal tissues is rare. Furthermore, it has
been shown that heparanase knock-out mice are viable and exhibit no
visible disorders. This indicates that little or no side effect can
derive from a heparanase inhibition strategy (Casu, B., et al.
2008, Non-anticoagulant heparins and inhibition of cancer;
Pathophysiol Haemost Thromb. 36: 195-203; Vlodaysky, I., et al.
2007, Heparanase: structure, biological functions, and inhibition
by heparin-derived minzetics of heparan sulfate, Curr Pharm Des.
13: 2057-2073; Naggi, A., et al. 2005, Modulation of the
Heparanase-inhibiting Activity of Heparin through Selective
Desulfation, Graded N-Acetylation, and Glycol Splitting, J. Biol.
Chem. 280: 12103-12113).
[0011] Heparin is a linear polydisperse sulfated polysaccharide of
the glycosaminoglycan family, endowed with anticoagulant and
antithrombotic activity. The saccharidic chains of heparin consist
of alternating uronic acid and D-glucosamine residues. The major
repeating unit is the disaccharide 2-O-sulfated L-iduronic acid
(IdoA2S)a(1-A) and N-, 6-O-sulfated D-glucosamine (GlcN6S). Minor
constituents are non-sulfated L-iduronic and D-glucuronic acid,
along with N-acetyl D-glucosamine and N-, 3-O-, 6-O-trisulfated
D-glucosamine (Casu, B., 2005, Structure and active domains of
heparin, In: Chemistry and Biology of Heparin and Heparan Sulfate,
Amsterdam: Elsevier. 1-28; Casu, B. and Lindahl U. 2001, Structure
and biological interactions of heparin and heparan sulfate, Adv
Carbohydr Chem Biochem 57: 159-206). Heparin, which is structurally
similar to HS, is capable of efficiently inhibiting heparanase, but
its use at high doses, in a heparanase inhibition strategy, is
impossible due to its anticoagulant activity.
[0012] Interestingly, low molecular weight heparins (LMWHs), which
are more bioavailable and less anticoagulant than heparin, appear
to prolong survival of cancer patients, probably through direct
effect on tumor growth and metastasis. This may be due, at least in
part, to inhibition of heparanase enzymatic activity (Zacharski, L.
R., and Lee, A. Y. 2008, Heparin as an anticancer therapeutic;
Expert Opin Investig Drugs 17: 1029-1037; Yang, Y. et al., 2007,
The syndecan-1 heparan sulfate proteoglycan is a viable target for
myeloma therapy; Blood 110: 2041-2048).
[0013] Effective inhibitors of the enzymatic activity of heparanase
have been selected in the prior art by studying heparanase
inhibition by non-anticoagulant heparins, most of which contain non
sulfated uronic acid residues modified by opening of the glucosidic
ring at 2-3 bond (glycol splitting). Said inhibitors differ in
their degree of 0-sulfation, N-acetylation and glycol splitting of
non-sulfated uronic acid residues both pre-existing and generated
by graded 2-O-desulfation (Naggi, A., 2005, Glycol-splitting as a
device for modulating inhibition of growth factors and heparanase
inhibition by heparin and heparin derivative, In: Chemistry and
Biology of Heparin and Heparan Sulfate, Amsterdam: Elsevier
461-481).
[0014] The term "glycol split" (gs) conventionally refers to
carbohydrate polymers that present opening of some monosaccharide
residues due to the break (glycol splitting) of one linkage between
two adjacent carbons, each bearing a hydroxyl group. The first
generation glycol split heparins, i.e. the so-called "reduced
oxyheparins" (RO-heparins), largely consisted of unmodified
polysulfated blocks occasionally interrupted by glycol split
residues corresponding to non-sulfated glucuronic acid/iduronic
acid residues that were present along the original chains (Naggi,
A., 2005, Glycol-splitting as a device for modulating inhibition of
growth factors and heparanase inhibition by heparin and heparin
derivative, In: Chemistry and Biology of Heparin and Heparan
Sulfate, Amsterdam: Elsevier 461-481). This chemical action on
heparin, modifying the glucuronic acid residues within the binding
site of ATIII, reduces or abolishes its anticoagulant activity,
making it possible to use it at high doses.
[0015] WO 92/17188 discloses anti-proliferative activity, with
respect to smooth muscle cells, of a non-anticoagulant species of
heparin. Said heparin is prepared by N-deacetylation of the
N-acetyl glucosamine units, which are a minor component of natural
heparin's chains, with a hydrazine-containing agent, followed by
periodate oxidation of diols or adjacent OH/NH.sub.2 groups to the
corresponding aldehydes. The oxidation is followed by reduction of
aldehydes to alcohols, without substantial fragmentation of the
glycosaminoglycan. The N-sulfated units are unaffected by the
oxidation-reduction.
[0016] N-desulfated heparins (Chemical Abstract Registry number
53260-52-9), also known as "heparamine" in the Merck index (14th
Editor, 2006), are known to be endowed with several effects: a
reduced anticoagulant activity, some activity against metastasis of
gastric cancer in mice, by inhibiting VEGF expression and
angiogenesis (Chen, J. L., et al. 2007, World J. Gastroenterol 21,
457-461) and prevention of hepatic/renal damage induced by ischemia
and reperfusion (Chen, J. L., et al. 2002, World J. Gastroenterol
8, 897-900). N-desulfated heparins are also known as intermediates
for the synthesis of various N-acylated heparins. The degree of
N-desulfation can range from 10% up to 100% of N-sulfated
glucosamine residues present in heparins (Huang, L. and Kerns, R.
J. 2006, Bioorg. Med Chem, 14, 2300-2313).
[0017] WO 01/55221 discloses glycosaminoglycans with a
2-O-desulfation degree not greater than 60% of the total uronic
acid units. Said glycosaminoglycans are devoid of anticoagulant
activity and show antiangiogenic activity based on the inhibition
of FGF. No activity is foreseen for inhibition of heparanase.
[0018] US 2008/0051567 discloses a compound corresponding to 100%
N-acetylated and 25% glycol split heparin, exerting little or no
anticoagulant activity and low release of growth factors from the
extracellular matrix, while inhibiting heparanase, tumor growth,
angiogenesis and inflammation in experimental animal models,
including Sanderson's model of myeloma.
[0019] Nevertheless, the need remains for providing improved
compounds with higher heparanase inhibition activity, higher
selectivity, improved bioavailability and efficacy for treating
heparanase-related pathologies, such as myeloma and other tumors.
These and other advantages of the invention, as well as additional
inventive features, will be apparent from the description of the
invention provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings incorporated in and forming a part
of the specification illustrate several aspects of the present
invention and, together with the description, serve to explain the
principles of the invention. In the drawings:
[0021] FIG. 1: prevalent structures generated by periodate
oxidation and borohydride reduction of a glycosaminoglycan: (1)
disaccharidic unit of a glycosaminoglycan polymer comprising one
uronic acid (iduronic and/or glucuronic) and one glucosamine
(2-N-acetylated, 2-N-unsubstituted and/or 2-N-sulfated), in which
the hydroxyl group (R4) can be substituted by a sulphate group or
non-substituted. After N-desulfation, glycosaminoglycan polymers
can comprise disaccharidic units comprising 2-N-acetylated
glucosamines (2) and 2-NH.sub.2 glucosamines (natural and/or
N-desulfated) (3). Periodate oxidation and borohydride reduction
lead to the conversion of adjacent diols of 2-O-non-sulfated uronic
acid residues (5, 6, 8) and adjacent OH/NH.sub.2 groups of 2-N- and
3-O-non-sulfated glucosamine (7, 8) to the corresponding aldehydes
(by oxidation) and then to the corresponding alcohols (by
reduction). Note that in disaccharide units containing residues of
an N-desulfated glucosamine and a 2-O-non-sulphate uronic acid,
both residues are converted to dialdehydes and then to glycol split
residues (8).
[0022] While the invention will be described in connection with
certain preferred embodiments, there is no intent to limit it to
those embodiments. On the contrary, the intent is to cover all
alternatives, modifications and equivalents as included within the
spirit and scope of the invention as defined by the appended
claims.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention relates to novel chemically modified
glycosaminoglycans, in particular heparin and LMWHs, which strongly
inhibit heparanase and its heparan sulfate degrading activity.
[0024] The novel compounds of the present invention, endowed with
heparanase inhibitory activity, are derivatives of N-desulfated and
optionally 2-O-desulfated glycosaminoglycans, in which at least
part of the adjacent diols and OH/NH.sub.2 have been converted into
the corresponding aldehyde, which aldehydes have been then reduced
to the corresponding alcohol. The conversion to aldehydes is
preferably carried out employing periodate, in conditions suitable
for breaking both the linkage of adjacent diols of uronic acid
residues and the C.sub.2-C.sub.3 linkage of glucosamine, bearing
respectively the amine and hydroxyl substituents. The starting
compounds can also contain naturally 2-O-non-sulfated uronic acid
residues. In particular, N-desulfation occurs on the N-sulfated
glucosamine residues, while O-desulfation is on 2-O-sulfated uronic
acid residues.
[0025] Preferably, the glycosaminoglycan derivatives of the present
invention originate from natural or synthetic glycosaminoglycans,
the latter being chemically or enzymatically prepared (Naggi, A. et
al., 2001, Toward a biotechnological heparin through combined
chemical and enzymatic modification of the Escherichia coli KS
polysaccharide, Seminars in Thrombosis and Hemostasis, 27: 5437),
such as unfractionated heparins, low molecular weight heparins
(LMWHs), heparan sulfates or fractions thereof; more preferably the
glycosaminoglycan derivatives derive from natural or synthetic
heparins or LMWHs.
[0026] Specific N-desulfation of N-sulfated glucosamine residues
substantially makes said residues susceptible to conversion to
corresponding aldehydes (and then to corresponding alcohols),
provided that these residues are also 3-O-non-sulfated. In FIG. 1
all of the disaccharidic units that can be present in a
glycosaminoglycan chain and their change after N-desulfation,
oxidation, and reduction reaction, are shown in a schematic
view.
[0027] As an example, heparin chains can naturally comprise from
about 5% to about 35% of 2-O-non-sulfated uronic acid residues,
from 0% to 50% of N-acetylated glucosamine residues and from about
0% to 6% of N-unsubstituted (neither N-sulfated, nor N-acetylated)
glucosamine residues. Different compositions depend on the heparin
source (animal species, organ sources) and on the extraction
procedures.
[0028] Every non-sulfated residue, both on carbon 2 and carbon 3,
of a glycosaminoglycan is susceptible of conversion to aldehyde.
Consequently, the extensive N-desulfation comprised in the process
of the present invention provides further residues susceptible of
said conversion over the percentage of susceptible units in natural
glycosaminoglycans, with an increase in the percentage of units in
which adjacent OH/NI-12 are converted to the corresponding
aldehydes (and then to the corresponding alcohols), however
preserving the natural content of 2-O-sulfated iduronic acid
residues. Optionally, chemically induced 2-O-desulfation of
glycosaminoglycans allows to modulate the ratio of glucosamine and
uronic acid susceptible to the oxidation and reduction reactions
according to the present invention.
[0029] The invention further relates to said glycosaminoglycan
derivatives N- and optionally 2-O-desulfated, in which adjacent
diols and OH/NH.sub.2 have been converted into the corresponding
aldehyde, with opening of the ring, which aldehydes have been then
reduced to the corresponding alcohol. The invention further relates
to a process for preparing said glycosaminoglycan derivatives and
also to their use as active ingredients of medicaments for treating
pathological conditions such as multiple myeloma and other cancers,
including their metastatic forms. Furthermore, the invention
relates to the use of said glycosaminoglycan derivatives in any
therapeutic indication gaining benefit from the inhibition of
heparanase. The invention also relates to pharmaceutical
compositions containing said N-desulfated and optionally
2-O-desulfated glycosaminoglycan derivatives, in which adjacent
diols and OH/NH.sub.2 have been converted into the corresponding
aldehyde, with opening of the ring, which aldehydes have been then
reduced to the corresponding alcohol.
[0030] The N- and, optionally, 2-O-desulfated glycosaminoglycan
derivatives of the present invention are obtainable by a process
comprising:
a) N-desulfation of from 25 to 100%, preferably of from 30% to 90%,
more preferably of from 45% to 80% of N-sulfated glucosamine
residues of a glycosaminoglycan; optionally the process further
comprises 2-O-desulfation up to 50%, preferably up to 25%, of 2-O
sulfated residues of a glycosaminoglycan; the obtained product
preferably comprises from 0% to 50% of N-acetylated glucosamine
residues, from 50% to 100% of N-non-sulfated glucosamine residues;
b) conversion into the corresponding aldehydes, preferably by
periodate oxidation, of the adjacent OH/NH.sub.2 of 2N-, 3-O-non
sulfated glucosamine residues and of adjacent diols of
2-O-non-sulfated uronic acid residues (chemically desulfated as
well as the naturally present non-sulfated ones along the original
chain); the 2N-, 3-O-non sulfated glucosamine residues can be
present as from 25% to 100%; and c) reduction of said aldehydes,
preferably by sodium borohydride, into the corresponding
alcohols.
[0031] Optionally, the process further comprises partial or total
deacetylation of N-acetylated residues of the
glycosaminoglycan.
[0032] In preferred embodiments, the glycosaminoglycan derivatives
of the present invention are obtained from natural or synthetic
(chemically or enzymatically prepared) glycosaminoglycans,
preferably from unfractionated heparins, LMWHs, heparan sulfate or
derivatives thereof. More preferably, the glycosaminoglycan
derivatives of the present invention are obtained from heparins or
LMWHs.
[0033] In a preferred embodiment, the oxidation, preferably
periodate oxidation, is performed under conditions to cleave both
the vicinal diols of uronic acids and the bond between the C.sub.2
and C.sub.3 of glucosamine, bearing respectively amino and hydroxyl
substituents.
[0034] In a preferred embodiment, modified glycosaminoglycan
samples, preferably modified heparin or LMWH, endowed with
different degrees of N-desulfation, are subjected to periodate
oxidation and sodium borohydride reduction in aqueous media,
performed by modification of known methods. Periodate oxidation may
be performed in the presence of NTA (nitrilotriacetic acid), a
chelating and sequestering agent used to reduce depolymerization,
in the presence of NaHCO.sub.3 or pyridine to alkalinize the
solution, or in the presence of MnCl.sub.2 with or without NTA.
Preferably, periodate oxidation is performed in the presence of
NTA. Preferably, oxidation is performed at pH comprised between 5.5
and 10.0, more preferably comprised between 6.0 and 9.0.
[0035] The present invention further relates to a process for
breaking the C.sub.2-C.sub.3 linkage of glucosamine residues of a
glycosaminoglycan, comprising: oxidation, preferably by periodate,
at a pH comprised between 5.5 and 10, more preferably between 6.0
and 9.0, of said glycosaminoglycan.
[0036] Preferably, the glucosamine residues in which adjacent
OH/NH.sub.2 have been converted into the corresponding aldehyde,
which aldehydes are then reduced to the corresponding alcohols, are
from 25% to 100%, more preferably from 50% to 100%, most preferably
from 60% to 90%, of the glucosamine residues of the
glycosaminoglycan.
[0037] The glycosaminoglycan derived compounds obtainable by the
process above preferably have a molecular weight of from 800 to
30,000 Da, depending on the process conditions and on the starting
glycosaminoglycan. When unfractionated heparin is employed as
starting material, the glycosaminoglycan derived compounds
obtainable by the process above preferably have a molecular weight
of from 3,000 to 20,000 Da, preferably from 4,000 to 12,000 Da.
[0038] The novel glycosaminoglycan derivatives of the present
invention have been unexpectedly shown to be strong heparanase
inhibitors in vitro and to inhibit myeloma in animal models.
[0039] The products with the higher number of units wherein the
adjacent diols and OH/NH.sub.2 have been converted to the
corresponding aldehydes, which aldehydes have been then reduced to
the corresponding alcohols, are also less sulfated with respect to
the natural glycosaminoglycans and to their RO derivatives.
Therefore, it is expected that they display less protein
interactions and more favorable pharmacokinetics than their
analogues with lower contents of modified residues.
[0040] The present invention further relates to the compounds
obtainable by the processes described above for use as
medicaments.
[0041] In particular, the present invention relates to the
compounds obtainable by the processes described above for use as
antimetastatic agents, as antitumor, preferably as antimyeloma.
[0042] Heparin and low molecular weight heparin derivatives
prepared according to the present invention, in spite of their low
sulfation degree, have shown effective inhibition of heparanase
activity, both in vitro and in vivo, in a multiple myeloma
experimental model.
[0043] Furthermore, the derivatives of the present invention have
shown, even at low molecular weights (see examples 5, 6 and 8),
heparanase inhibitory activity higher than that of RO heparins
obtained from 2-O-desulfated heparins of similar molecular weight.
The latters are show in table 1.
TABLE-US-00001 TABLE 1 Average Heparanase % of glycol split
molecular weight, inhibition Sample uronic acids MW (kDa) IC.sub.50
(ng/ml) RO 1 Heparin 28 17 8 RO 2 Heparin 26 10 50 RO 3 Heparin 23
7 500 RO 4 Heparin 23 5 750
[0044] Data show a general trend to reduced heparanase inhibiting
activity with the lowering of the molecular weight of glycol split
heparin of RO type.
EXAMPLES
[0045] Compounds Preparation
[0046] N-desulfation of unfractionated heparin (hereinafter UFH)
disclosed in the following examples was performed by modification
of known methods (Inoue, Y. and Nagasawa, K. 1976, Selective
N-desulfation of heparin with dimethyl sulfoxide containing water
or methanol, Carbohydr Res 46 (1) 87-95). The degree of
N-desulfation was determined by .sup.13C-NMR (Naggi, A., et al.
2001, Generation of anti-factor Xa active, 3-O-sulfated
glucosamine-rich sequences by controlled desulfation of
oversulfated heparins, Carbohydr. Res. 336, 4, 283-290).
[0047] Samples of modified heparins, endowed with different degree
of N-desulfation, were subjected to periodate oxidation to give
split units with two aldehyde groups and sodium borohydride
(NaBH.sub.4) reduction in aqueous medium to give final heparin
derivatives; both reactions were performed by modification of known
methods. Periodate oxidation was preferably performed in the
presence of NaHCO.sub.3, pyridine, MnCl.sub.2, or MnCl.sub.2 with
NTA. Graded 2-O-desulfation of UFH was performed following
modification of known methods (Jaseja, M. et al. 1989, Novel regio-
and stereo-selective modifications of heparin in alkaline solution.
Nuclear magnetic resonance spectroscopic evidence, Canad J Chem,
67, 1449-1455; R. N. Rej Arthur S. Perlin 1990, Base-catalyzed
conversion of the a-L-iduronic acid 2-sulfate unit of heparin into
a unit of a-L-galacturonic acid, and related reactions, Carbohydr.
Res. 200, 25, 437-447; Casu, B. et al. 2004, Undersulfated and
Glycol-Split Heparins Endowed with Antiangiogenic Activity, J. Med.
Chem., 47, 838-848). Hereafter "RO" indicates the % of glycol split
residues in which adjacent diols and OH/NH.sub.2 have been
converted into the corresponding aldehyde and then into the
corresponding alcohols, over the total glycosaminoglycan
residues.
[0048] In Vitro Testing
[0049] Based on previous studies of Bisio et al. (Bisio, A. et al.
2007, High-performance liquid chromatographic/mass spectrometric
studies on the susceptibility of heparin specie to cleavage by
heparanase, Sem Thromb Hemost 33 488-495), heparanase inhibiting
activity was determined in vitro by the group of Prof. Vlodaysky at
the University of Haifa, Israel, according to the method described
by Hammond et al. (Hammond et al. 2010, Development of a
colorimetric assay for heparanase activity suitable for kinetic
analysis and inhibitor screening, Anal Biochem. 396, 112-6).
Briefly, heparanase can cleave the synthetic pentasaccharide,
Fondaparinux, which is an antithrombotic drug, structurally
corresponding to the antithrombin binding site of heparin. After
hydrolysis by heparanase, a trisaccharide and a reducing
disaccharide are obtained. The latter can be easily quantified in
order to assess heparanase activity. In the present examples, the
assay solution comprises (100 .mu.l) 40 mM sodium acetate buffer pH
5.0 and 100 mM Fondaparinux (GlaxoSmithKline), with or without
inhibitor sample. Heparanase was added to a final concentration of
140 pM at the beginning of the assay. The plates were sealed with
adhesive tape and incubated at 37.degree. C. for 2-24 hours. The
assay was stopped by addition of 100 .mu.L of a 1.69 mM
4-[3-(4-iodophenyl)-1H-5 tetrazolio]-1,3-benzene disulfonate
(WST-1, Aspep, Melbourne, Australia) solution in 0.1M NaOH. The
plates were resealed with adhesive tape and developed at 60.degree.
C. for 60 minutes. The absorbance was measured at 584 nm (Fluostar,
BMG, Labtech). In each plate, a standard curve constructed with
D-galactose as the reducing sugar standard was prepared in the same
buffer and volume over the concentration range of 2 to 100 .mu.M.
The IC.sub.50 value was determined. Results obtained using the
above cited colorimetric assay were validated using a different
test that employs an extracellular matrix (ECM) labeled with
radioactive sulfate as substrate. Briefly, the ECM substrate is
deposited by cultured corneal endothelial cells and hence closely
resembles the subendothelial basement membrane in its composition,
biological function and barrier properties. Detailed information
about the preparation of sulfate labeled ECM and its use for the
heparanase assay can be found in: Vlodaysky, I., Current Protocols
in Cell Biology, Chapter 10: Unit 10.4, 2001.
[0050] In Vivo Testing
[0051] The antimyeloma activity in vivo was tested substantially
following the procedure described in Yang Y et al. (Yang, Y. et al.
2007, The syndecan-1 heparan sulfate proteoglycan is a viable
target for myeloma therapy, Blood 110: 2041-2048). Briefly, CB17
scid/scid mice aged 5 to 6 weeks were obtained from Arlan
(Indianapolis, Ind.) or Charles River Laboratories (USA). Mice were
housed and monitored in the animal facility of the University of
Alabama in Birmingham. All experimental procedures and protocols
were approved by the Institutional Animal Care and Use Committee.
Some 1.times.10.sup.6 heparanase-expressing CAG myeloma cells (high
or low expressing) were injected subcutaneously into the left flank
of each mouse. Ten days after injection of tumor cells, mice were
implanted with Alzet osmotic pumps (Durect Corporation, Cupertino,
Calif.) on the right flank. Pumps contained either solution of test
compounds (new heparin derivatives) or phosphate buffer (PBS) as
control. The solution was delivered continuously for 14 days. After
14 days, the animals were killed and the wet weight of the
subcutaneous tumors and the mean sera kappa level were assayed and
compared among the experimental groups by log-rank test (p<0.05
was considered statistically significant).
[0052] Weekly luciferase bioluminescence imaging provides
quantitative data on primary tumors and tracks metastasis within
bone as well as soft tissues. Notably, the SCID-hu model is unique
in that human tumor cells are injected directly into small pieces
of human fetal bone implanted subcutaneously in SCID mice, thus
closely recapitulating human myeloma.
[0053] General Procedure of NMR Analysis
[0054] Spectra were recorded at 25.degree. C. on a Bruker Avance
500 spectrometer (Karlsruhe, Germany) equipped with a 5-mm TCI
cryoprobe or with a 10 mm BBO probe. Integration of peak area or
volumes in the spectra was made using standard Bruker TopSpin 2.0
software.
N-Desulfation of Unfractionated Heparin
Example 1 (G8220)
[0055] UFH (4.01 g, lot. G3378) was dissolved in water (32 ml) and
treated under stirring with Amberlite IR 120 (H+, 144 ml). The
filtered acid solution was brought to pH 7 with pyridine, then
concentrated to dryness under reduced pressure. The resulting
pyridinium salt was dissolved in 40 ml of a mixture of
DMSO:H.sub.2O (95:5 by volume), then stirred at 25.degree. C. for
48 hours. After dilution with 40 ml of water, the solution was
dialyzed at 4.degree. C. for 16 hours against distilled water in
membrane (cut-off: 3,500 Da). Concentration under reduced pressure
and lyophilization gave: G8220 (2.7 g), yield=67% w/w, MW=19,100
Da, N-desulfation degree determined by .sup.13C-NMR=74.7% of the
total glucosamine residues, 2-0 sulfated uronic acid determined by
.sup.13C-NMR=18% of the total monosaccharides.
Example 2 (G8343)
[0056] Following the procedure described in Example 1, a sample of
UFH (0.25 g, lot. G3378) was converted in the corresponding
pyridinium salt, which was N-desulfated in a mixture of DMSO:MeOH
(95:5 by volume). After 2 hours under stirring at 25.degree. C.,
reaction mixture was processed, following the same final procedure
described in Example 1, to give G8343 (0.172 g), yield=69% w/w,
MW=18,000 Da, N-desulfation degree determined by .sup.13C-NMR=63.3%
of the total glucosamine residues, 2-0 sulfated uronic acid
determined by .sup.13C-NMR=19% of the total monosaccharides.
Example 3 (G8516)
[0057] Starting from a sample of UFH (0.25 g, lot G3378) and
following the procedure described in Example 2, but reducing to 40
minutes the N-desulfation reaction time, G8516 was obtained (0.17
g), yield=68%, N-desulfation degree by .sup.13C-NMR=49.7% of the
total glucosamine residues, 2-0 sulfated uronic acid determined by
.sup.13C-NMR=17% of the total monosaccharides.
Example 4 (G8147)
[0058] UFH (2.5 g, lot. G3378) was dissolved in water (20 ml) and
treated under stirring with Amberlite IR 120 (H+, 90 ml). The
filtered acid solution was brought to pH 7 with pyridine, then
concentrated to dryness under reduced pressure. The resulting
pyridinium salt was dissolved in 25 ml of a mixture of DMSO:MeOH
(90:10 by volume), then stirred at 25.degree. C. for 18 hours.
After dilution with 25 ml of water, the solution was dialyzed at
4.degree. C. for 16 hours against distilled water in membrane
(cut-off: 3,500 Da). Concentration under reduced pressure and
lyophilization gave: G8147 (1.9 g), yield=76% w/w, MW=18,200 Da,
N-desulfation degree by .sup.13C-NMR=60% of the total glucosamine
residues.
Example 5 (G9416)
[0059] UFH (5 g, lot. G3378) was dissolved in water (40 ml) and
treated under stirring with Amberlite IR 120 (H+, 90 ml). The
filtered acid solution was brought to pH 7 with pyridine, then
concentrated to dryness under reduced pressure. The resulting
pyridinium salt was dissolved in 100 ml of a mixture of DMSO:MeOH
(95:5 by volume), then stirred at 25.degree. C. for 18 hours. After
dilution with 100 ml of water, the solution was dialyzed at
4.degree. C. for 16 hours against distilled water in membrane
(cut-off: 3,500 Da). Concentration under reduced pressure and
lyophilization gave: G9416 (3.65 g), yield=73% w/w, MW=18,800 Da,
N-desulfation degree by .sup.13C-NMR=77% of the total glucosamine
residues.
Example 6 (68079)
[0060] UFH (1 g, lot. G3378) was dissolved in water (8 ml) and
treated under stirring with Amberlite IR 120 (H+, 90 ml) for 30
minutes. The filtered acid solution was brought to pH 7 with
pyridine, then concentrated to dryness under reduced pressure. The
resulting pyridinium salt was dissolved in 10 ml of a mixture of
DMSO:MeOH (95:5 by volume), then stirred at 25.degree. C. for 16
hours. After dilution with 10 ml of water, the solution was
dialyzed at 4.degree. C. for 3 days against distilled water in
membrane (cut-off: 3,500 Da). Concentration under reduced pressure
and lyophilization gave: G8079 (1 g), yield=100% w/w, N-desulfation
degree by .sup.13C-NMR=60% of the total glucosamine residues.
Periodate Oxidation and Sodium Borohydride Reduction of
N-Desulfated Heparins
Example 7 (G8340)
[0061] A sample of G8220 of example 1 (0.25 g, 74.7% of
N-desulfated heparin residues), dissolved in water (7.3 ml) and
cooled to 4.degree. C., was added to an equal volume of 0.2 M
NaIO.sub.4. The pH value was adjusted to 6.8 with 2M NaHCO.sub.3
(about 2.1 ml) and, under stirring in the dark at 4.degree. C.,
0.08M nitrilotriacetic acid (NTA, 10 ml) was added to the solution.
The pH value from 4.0 was brought to 6.6 by adding 2M NaHCO.sub.3
and the reaction mixture was kept under stirring at 4.degree. C.
for 8 hours. The excess of periodate was quenched by adding
ethylene glycol (0.73 ml); after 1 hour the reaction mixture was
desalted by dialysis against distilled water in membrane (cut-off:
3,500 Da) at 4.degree. C. for 16 hours. The desalted solution was
treated with NaBH.sub.4 (0.164 g, 3.4 mmoles), stirred for 3 hours
at 25.degree. C., then its pH value was brought to 4 with 1N HCl
for quenching the NaBH.sub.4 excess, and after a 10 minutes
stirring, neutralized with 0.1N NaOH. After dialysis against
distilled water at 4.degree. C. for 16 hours in membrane (cut-off:
3,500 Da), concentration under reduced pressure and freeze drying,
0.202 g of G8340 was obtained, yield=90% w/w, MW=8,400 Da. The
percentages, over the total of monosaccharide residues, of RO
(53%), IdoA2S (35%), GlcNAc (9%) and GlcNH.sub.2 (12%) were
determined by .sup.13C-NMR.
[0062] In vitro heparanase inhibition: IC.sub.50=20 ng/ml.
[0063] In vivo antimyeloma activity: 60 mg/Kg/day for 14 days: 75%
tumor inhibition and 60% serum K inhibition.
Example 8 (G8438)
[0064] Starting from G8343 of Example 2 (0.171 g of 63.3% of
N-desulfated heparin residues) and following the same procedure
described in Example 7, G8438 was obtained (91.4 mg), yield=82%,
MW=6,800 Da. The percentages of RO (38%), IdoA2S (32%), GlcNAc
(8%), GlcNH.sub.2 (4%), were determined by .sup.13C-NMR.
[0065] In vitro heparanase inhibition IC.sub.50=60 ng/ml.
Example 9 (G8588)
[0066] Starting from G8516 of Example 3 (0.171 g of 44% of
N-desulfated heparin residues) and following the procedure
described in Example 7, G8588 (0.136 g) was obtained, yield=80%,
MW=11,000 Da. The percentages of GlcNAc (30%), GlcNH.sub.2 (13%),
IdoA2S (34%), RO (37%) were determined by .sup.13C-NMR.
Example 10 (G9578)
[0067] Starting from G9416 of Example 5, following the procedure
described in Example 7, G9578 was obtained, yield=89%, MW=6,300 Da,
N-desulfation degree by .sup.13C-NMR=48% of the total glucosamine
residues. The percentages of RO (45%) and IdoA2S (35%) over the
total residues of glycosaminoglycan were determined by
.sup.13C-NMR. In vitro and in vivo testing on the inventive product
yielded the following results:
[0068] In vitro heparanase inhibition: IC.sub.50=75 ng/ml; In vivo
antimyeloma activity (60 mg/kg day for 14 days): 63% tumor
inhibition.
Example 11 (G8188)
[0069] A sample of N-desulfated heparin G8147 of Example 4 (0.25 g,
60% N-desulfated heparin residues), dissolved in water (7.3 ml) and
cooled to 4.degree. C., was added to an equal volume of 0.2M
NaIO.sub.4. The pH value was adjusted to 6.8 with 2M NaHCO.sub.3
(about 2.1 ml), under stirring in the dark at 4.degree. C. for 16
hours. The excess of periodate was quenched by adding ethylene
glycol (0.73 ml) and, after 1 hour, the reaction mixture was
desalted by dialysis against distilled water in membrane (cut-off:
3,500 Da) at 4.degree. C. for 16 hours. The desalted solution was
treated with NaBH.sub.4 (0.164 g, 3.4 mmoles), stirred for 3 hours
at 25.degree. C., then its pH value was brought to 4 with 1N HCl
for quenching the NaBH.sub.4 excess and, after a 10 minutes
stirring, it was neutralized with 0.1N NaOH. After dialysis against
distilled water at 4.degree. C. for 16 hours in membrane (cut-off:
3,500 Da), concentration under reduced pressure and freeze drying,
0.168 g of G8188 was obtained, yield=67% w/w, MW=3,460 Da. The
percentages of RO (43%), IdoA2S (40%), GlcNAc (6%) and GlcNH.sub.2
(4%) were determined by .sup.13C-NMR.
Example 12 (G8189)
[0070] A sample of G8147 (0.25 g, 60% of N-desulfated heparin
residues), dissolved in water (7.3 ml) and cooled to 4.degree. C.,
was added to an equal volume of 0.2M NaIO.sub.4. The pH value was
adjusted to 6.8 with pyridine (5% v/v, about 730 .mu.l), under
stirring in the dark at 4.degree. C. for 16 hours. The excess of
periodate was quenched by adding ethylene glycol (0.73 ml) and,
after 1 hour, the reaction mixture was desalted by dialysis against
distilled water in membrane (cut-off: 3,500 Da) at 4.degree. C. for
16 hours. The desalted solution was treated with NaBH.sub.4 (0.164
g, 3.4 mmoles), stirred for 3 hours at 25.degree. C., then its pH
value was brought to 4 with 1N HCl for quenching the NaBH.sub.4
excess and, after 10 minutes of stirring, neutralized with 0.1N
NaOH. After dialysis against distilled water at 4.degree. C. for 16
hours in membrane (cut-off: 3,500 Da), concentration under reduced
pressure and freeze drying, 0.181 g of G8189 was obtained, yield=7
2% w/w, MW=5,150 Da. The percentages of RO (49%), IdoA2S (39%),
GlcNAc (7%) and GlcNH.sub.2 (7%) were determined by
.sup.13C-NMR.
Example 13 (G8217)
[0071] A sample of G8147 (0.25 g, 60% of N-desulfated heparin
residues), dissolved in water (7.3 ml) and cooled to 4.degree. C.,
was added to an equal volume of 0.2 M NaIO.sub.4. The pH value was
adjusted to 6.8 with 2M NaHCO.sub.3 (about 2.1 ml) and 30 ml of
MnCl.sub.2 0.05M (the final concentration in the solution was
0.00001M) were added under stirring in the dark at 4.degree. C. for
16 hours. The excess of periodate was quenched by adding ethylene
glycol (0.73 ml). During the night, the sample precipitated because
the pH became 8 then its pH value was brought to 6 with 1N HCl.
After 1 hour, the reaction mixture was desalted by dialysis against
distilled water in membrane (cut-off: 3,500 Da) at 4.degree. C. for
16 hours. The desalted solution was treated with NaBH.sub.4 (0.164
g, 3.4 mmoles), stirred for 3 hours at 25.degree. C., then its pH
value was brought to 4 with 1N HCl for quenching the NaBH.sub.4
excess and after 10 minutes of stirring, neutralized with 0.1N
NaOH. After dialysis against distilled water at 4.degree. C. for 16
hours in membrane (cut-off: 3,500 Da), concentration under reduced
pressure and freeze drying, 0.230 g of G8217 was obtained,
yield=92% w/w, MW=7,455 Da. The percentages of RO (31%), IdoA2S
(29%), GlcNAc (8%), and GlcNH.sub.2 (6%) on the total of
glycosaminoglycan residues were determined by .sup.13C-NMR.
Example 14 (G8219)
[0072] A sample of G8147 (0.25 g, 60% of N-desulfated heparin
residues), dissolved in water (7.3 ml) and cooled to 4.degree. C.,
was added to an equal volume of 0.2 M NaIO.sub.4. The pH value was
adjusted to 6.8 with 2M NaHCO.sub.3 (about 1.2 ml) and, under
stirring in the dark at 4.degree. C., 0.08 M nitrilotriacetic acid
(NTA, 10 ml) and 31 ml of MnCl.sub.2 0.05M were added to the
solution. The pH value was brought from 4.0 to 6.3 by adding 2M
NaHCO.sub.3 and the reaction mixture was kept under stirring at
4.degree. C. for 8 hours. The excess of periodate was quenched by
adding ethylene glycol (0.73 ml) and, after 1 hour, the reaction
mixture was desalted by dialysis against distilled water in
membrane (cut-off: 3,500 Da) at 4.degree. C. for 16 hours. The
dialyzed solution was treated with NaBH.sub.4 (0.164 g, 3.4
mmoles), stirred for 3 hours at 25.degree. C., then its pH value
was brought to 4 with 1N HCl for quenching the NaBH.sub.4 excess,
and after 10 minutes of stirring, neutralized with 0.1N NaOH. After
dialysis against distilled water at 4.degree. C. for 16 hours in
membrane (cut-off: 3,500 Da), concentration under reduced pressure
and freeze drying, 0.202 g of G8219 was obtained, yield=90% w/w,
MW=7,330 Da. The percentages of RO (54%), IdoA2S (36%), GlcNAc (9%)
and GlcNH.sub.2 (8%) were determined by .sup.13C-NMR.
Comparative Example 15 (G8092)
[0073] To a sample of G8079 (1 g, N-desulfated heparin), dissolved
in water (29.2 ml) and cooled to 4.degree. C., an equal volume of
NaIO.sub.4 (pHs) was added, and the reaction mixture was kept under
stirring at 4.degree. C. for 8 hours. The excess of periodate was
quenched by adding ethylene glycol (2.9 ml) and, after 1 hour, the
reaction mixture was desalted by dialysis against distilled water
in membrane (cut-off: 3,500 Da) at 4.degree. C. for 16 hours. The
dialyzed solution was treated with NaBH.sub.4 (0.657 g, 3.4
mmoles), stirred for 3 hours at 25.degree. C., then its pH value
was brought to 4 with 1N HCl for quenching the NaBH.sub.4 excess,
and after 10 minutes of stirring, neutralized with 0.1 N NaOH.
After dialysis against distilled water at 4.degree. C. for 72 hours
in membrane (cut-off: 3,500 Da), concentration under reduced
pressure and freeze drying, 0.643 g of G8092 was obtained,
yield=64% w/w, MW=6,064 Da. The .sup.13C-NMR analysis shows a peak
at 95 ppm of N-desulfated glucosamine. The oxidation reaction at
acidic pH does not occur.
[0074] All references, including publications, patent applications,
and patents cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0075] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) is to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. The terms "comprising,"
"having," "including," and "containing" are to be construed as
open-ended terms (i.e., meaning "including, but not limited to,")
unless otherwise noted. Recitation of ranges of values herein are
merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range,
unless otherwise indicated herein, and each separate value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0076] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Variations of those preferred embodiments may
become apparent to those of ordinary skill in the art upon reading
the foregoing description. The inventors expect skilled artisans to
employ such variations as appropriate, and the inventors intend for
the invention to be practiced otherwise than as specifically
described herein. Accordingly, this invention includes all
modifications and equivalents of the subject matter recited in the
claims appended hereto as permitted by applicable law. Moreover,
any combination of the above-described elements in all possible
variations thereof is encompassed by the invention unless otherwise
indicated herein or otherwise clearly contradicted by context.
* * * * *