U.S. patent application number 15/008620 was filed with the patent office on 2017-08-03 for composition comprising polyglucosamine-glyoxylate solutions mixed with hyaluronan.
This patent application is currently assigned to Oligo Medic inc. The applicant listed for this patent is Oligo Medic inc. Invention is credited to Abdellatif CHENITE, Amine Selmani.
Application Number | 20170216341 15/008620 |
Document ID | / |
Family ID | 59385252 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170216341 |
Kind Code |
A1 |
Selmani; Amine ; et
al. |
August 3, 2017 |
COMPOSITION COMPRISING POLYGLUCOSAMINE-GLYOXYLATE SOLUTIONS MIXED
WITH HYALURONAN
Abstract
The present disclosure relates to a method which allows direct
formation of gel-like solutions of polyglucosamine at neutral
pH.apprxeq.7 to 8, eliminating the need of prior dissolution of
polyglucosamine in acidic environment; and to a homogeneous liquid
combination of polyglucosamine-glyoxylate with hyaluronan.
Inventors: |
Selmani; Amine; (Montreal,
CA) ; CHENITE; Abdellatif; (Kirkland, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oligo Medic inc |
Laval |
|
CA |
|
|
Assignee: |
Oligo Medic inc
Laval
CA
|
Family ID: |
59385252 |
Appl. No.: |
15/008620 |
Filed: |
January 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 9/0019 20130101;
A61K 9/06 20130101; A61K 31/728 20130101; A61K 47/34 20130101; A61K
47/36 20130101; A61K 2300/00 20130101; A61K 2300/00 20130101; A61K
31/722 20130101; A61K 31/722 20130101; A61K 31/728 20130101; A61K
9/08 20130101 |
International
Class: |
A61K 31/722 20060101
A61K031/722; A61K 31/19 20060101 A61K031/19; A61K 45/06 20060101
A61K045/06; A61K 31/728 20060101 A61K031/728 |
Claims
1. A composition comprising a polyglucosamine, glyoxylate and
hyaluronan.
2. The composition of claim 1, wherein the polyglucosamine is at
least one of chitin, chitosan, polyglucosaminoglycans, chondroitin,
heparin, keratan and dermatan.
3. The composition of claim 1, wherein the polyglucosamine is
chitosan.
4. The composition of claim 3, wherein the concentration of
chitosan ranges from 0.1% to 5.0%.
5. The composition of claim 4, wherein the concentration of
chitosan ranges from 1.0% to about 3.0%.
6. The composition of claim 3, wherein said chitosan has a degree
of deacetylation (DDA) ranging between 70% and 100% and a molecular
weight (Mw) ranging from 50 kDa to 1000 kDa.
7. The composition of claim 6, wherein said chitosan has a DDA of
80% to 99%, and a Mw of 200 kDa to 500 kDa.
8. The composition of claim 1, further comprising at least one
material or compound selected from the group consisting of cells,
stem cells, peptides, growth factors, human blood, platelet-rich
plasma, nucleotides, bone, bone-derived materials, calcium
phosphates, calcium carbonates, bioglasses, ceramics, drugs,
cytolines, osteogenic agents, osteoinductive agents and imaging
agents.
9. The composition of claim 1, wherein said composition is for
treating a tissue or organ within a mammalian or human body.
10. The composition of claim 9, wherein the tissue or organ
comprises articular cartilage, fibrocartilage, meniscus,
intervertebral discs, bone tissues, muscular tissues, nerve and
spinal cord soft-tissues, skin or dermal tissues.
11. The composition of claim 1, wherein the composition is for
treating body joint functions or cartilage defects.
12. The composition of claim 11, the composition is for treating
inflammatory joint conditions, osteoarthritis, vitreous humor of
the eye, cataract, or corneal grafts.
13. The composition of claim 12, wherein the inflammatory joint
conditions are caused by arthritis.
14-16. (canceled)
17. A method of preparing a composition of polyglucosamine,
comprising the step of dissolving the polyglucosamine in a solution
of glyoxylate at a pH between of 7 and 8.
18. The method of claim 17, wherein the polyglucosamine is at least
one of chitin, chitosan, polyglucosaminoglycans, chondroitin,
heparin, keratan and dermatan.
19. The method of claim 17, wherein the polyglucosamine is
chitosan.
20-23. (canceled)
24. The method of claim 17, further comprising the step of mixing
the composition with a negatively charged polyelectrolyte.
25. The method of claim 24, wherein the negatively charged
polyelectrolyte is hyaluronan (HA) or alginate.
26. The method of claim 24, wherein the negatively charged
polyelectrolyte is hyaluronan (HA).
27. (canceled)
Description
TECHNICAL FIELD
[0001] The present description relates to a composition comprising
polyglucosamine-glyoxylate solutions mixed with hyaluronan.
BACKGROUND ART
[0002] Polyglucosamine polymers are linear amino-polysaccharides
composed of D-glucosamine and N-acetyl-D-glucosamine units linked
by (1-4) glycosidic bonds. They are produced by alkaline
deacetylation of chitin, a component of the exoskeleton of
crustaceans, the cuticles of insects and the cell walls of fungi
(Muzzarelli et al., 1986, Chitin in Nature and Technology, Plenium
Press, New York). Polyglucosamine contains free amine (--NH.sub.2)
groups and may be characterized by the proportion of
N-acetyl-D-glucosamine units and D-glucosamine units, which is
expressed as the degree of deacetylation (DDA) of the fully
acetylated polymer chitin. The properties of polyglucosamine, such
as the solubility and the viscosity, depend on the degree of
deacetylation (DDA), which represents the percentage of glucosamine
monomers, and the molecular weight (Mw).
[0003] Polyglucosamine polymers have been proposed in various
formulations, alone and with other components, to stimulate repair
of dermal, corneal and hard tissues (see for example U.S. Pat. Nos.
4,572,906; 4,956,350; 5,894,070; 5,902,798; and 6,124,273; and WO
98/22114). Biodegradability, adhesiveness, and prevention of
dehydration as well as the ability to form barrier to bacterial
invasion are the properties of polyglucosamine that are most
commonly cited as beneficial for the wound healing. The interesting
hemostatic potential of polyglucosamine has also been behind their
application to stop bleeding at grafts and wound sites (U.S. Pat.
No. 4,532,134). Some studies claim that the hemostatic activity of
polyglucosamine derives solely from their ability to agglutinate
red blood cells while others believe that the polycationic amine
character can activate platelets to release thrombin and initiate
the classical coagulation cascade. It has been proposed in U.S.
Pat. No. 5,773,033 the use of polyglucosamine as a hemostatic agent
in combination with fibrinogen and purified autologous
platelets.
[0004] The non-solubility of polyglucosamine polymers at
physiological pH constitutes the main technical difficulty limiting
their use in a solution state. Thus typically, dissolution of
polyglugosamine is achieved via the protonation of amine groups in
acidic aqueous solutions. The resulting solutions have a pH ranging
from 3.0 to 5.5 and if neutralized, the polymer remains soluble up
to a pH near 6.2. Beyond this pH value, further deprotonation of
the amino-groups reduces inter-chain electrostatic repulsion and
allows attractive forces of hydrogen bonding, hydrophobic and van
der Waals interactions to cause polymer precipitation. The
dissolution of polyglucosamine can be carried out using solution of
mineral acids, such HCl or organic acids, such as acetic acid.
[0005] However, it seems that under particular conditions, the
neutralization of polyglucosamine solution up to physiological pH
around 7 can be achieved without inducing precipitation. U.S. Pat.
No. 6,344,488 discloses a pH-dependent temperature controlled
polyglucosamine composition prepared by neutralizing, up to pH
between 6.8 and 7.2, with mono-phosphate dibasic salts of polyols
or sugars, such as sodium .beta.-glycerophosphate. U.S. patent
applications nos. 2009/0270514 and 2010/0113618 described the
preparation of thermogelling polyglucosamine solutions by using,
either a (NH.sub.4).sub.2HPO.sub.4 solution or a NaOH solution. And
more recently, U.S. patent application no. 2012/0052012 teach the
preparation of thermogelling solution of polyglucosamine,
neutralized to around 7, by glucosamine carbonate and glucosamine
phosphate.
[0006] Muzzarelli et al. (1982, Carbohydrate Research, 107:
199-214; U.S. Pat. No. 4,835,265) describes the use of oxoacids,
such as glyoxylic acid to modify chitosan and produce
N-carboxymethyl grafted chitosan. The carboxymethyl group is
permanently grafted onto the chitosan chain. The method consists of
adding glyoxylic acid to aqueous suspensions of chitosan to cause
dissolution of chitosan and gel formation at pH between 4.5 and
5.5. Then alkaline NaOH solution is added to evidence the formation
of a Schiff base, namely N-(carboxymethylidene)-chitosan, which is
reduced by sodium cyanoborohydride at room temperature to give
N-carboxymethyl chitosan.
[0007] There is no report or publication teaching the preparation
of gel-like solutions of polyglucosamine, just by dispersing
polyglucosamine powder into a solution directly at a pH between 7
and 8.
[0008] There is still a need to be provided with a method of
preparing a gel-like solution of polyglucosamine at neutral pH,
without the need of prior dissolution of polyglucosamine in an
acidic environment, allowing the resulting dissolved
polyglucosamine to be mixed with negatively charged
polyelectrolytes to form homogenous liquid mixtures, without
inducing precipitation.
SUMMARY
[0009] In accordance with the present description there is now
provided a method of preparing a composition of polyglucosamine,
comprising the step of dissolving the polyglucosamine in a solution
of glyoxylate at a pH between of 7 and 8.
[0010] In accordance with the present description there is also
provided a composition comprising a polyglucosamine, glyoxylate and
hyaluronan.
[0011] In an embodiment, the polyglucosamine is at least one of
chitin, chitosan, polyglucosaminoglycans, chondroitin, heparin,
keratan and dermatan.
[0012] In another embodiment, the polyglucosamine is chitosan.
[0013] In an additional embodiment, the concentration of chitosan
ranges from 0.1% to 5.0%; from 1.0% to about 3.0%.
[0014] In an embodiment, the chitosan has a degree of deacetylation
(DDA) ranging between 70% and 100% and a molecular weight (Mw)
ranging from 50 kDa to 1000 kDa.
[0015] In a further embodiment, the chitosan has a DDA of 80% to
99%, and a Mw of 200 kDa to 500 kDa.
[0016] In a further embodiment, the method described herein further
comprises the step of mixing the composition with a negatively
charged polyelectrolyte.
[0017] In an embodiment, the negatively charged polyelectrolyte is
hyaluronan (HA) or alginate.
[0018] In another embodiment, the negatively charged
polyelectrolyte is hyaluronan (HA).
[0019] In an embodiment, the composition described herein further
comprises at least one material or compound selected from the group
consisting of cells, stem cells, peptides, growth factors, human
blood, platelet-rich plasma, nucleotides, bone, bone-derived
materials, calcium phosphates, calcium carbonates, bioglasses,
ceramics, drugs, cytolines, osteogenic agents, osteoinductive
agents and imaging agents.
[0020] In another embodiment, the composition is for treating a
tissue or organ within a mammalian or human body.
[0021] In another embodiment, the mammalian encompassed can be an
animal, such as a horse, a dog or a cat.
[0022] In a particular embodiment, the tissue or organ comprises
articular cartilage, fibrocartilage, meniscus, intervertebral
discs, bone tissues, muscular tissues, nerve and spinal cord
soft-tissues, skin or dermal tissues.
[0023] In a further embodiment, the composition is for treating
body joint functions or cartilage defects.
[0024] In another embodiment, the composition is formulated for
treating inflammatory joint conditions.
[0025] In an embodiment, the composition is formulated to be
injected into the patient.
[0026] In a further embodiment, the inflammatory joint conditions
are caused by arthritis.
[0027] It is also provided the use of the composition described
herein for treating inflammatory joint conditions, osteoarthritis,
vitreous humor of the eye, cataract, or corneal grafts.
[0028] It is also provided the use of the composition described
herein fin the manufacture of a medicament for treating
inflammatory joint conditions, osteoarthritis, vitreous humor of
the eye, cataract, or corneal grafts.
[0029] It is also provided the use of the composition described
herein in the manufacture of a viscoelastic ophthalmic composition
for cataract surgery.
[0030] It is also provided the use of the composition described
herein in the manufacture of a cosmetics, ophthalmology,
therapeutics delivery, wound healing or tissue engineering
composition.
[0031] It is also provided the use of the composition described
herein for treating a tissue or organ within a mammalian or human
body.
[0032] It is also provided the use of the composition described
herein in the manufacture of a medicament for treating a tissue or
organ within a mammalian or human body.
[0033] It is also provided the use of the composition described
herein for treating body joint functions or cartilage defects.
[0034] It is also provided the use of the composition described
herein in the manufacture of a medicament for treating body joint
functions or cartilage defects.
DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 shows the structures of polyglucosamine and
hyaluronic acid.
[0036] FIG. 2 shows the viscous and clear and homogeneous solution
obtained upon mixing polyglucosamine-glyoxylate with hyaluronic
acid sodium salt (HA).
[0037] FIG. 3 is a schematic illustration showing the coexistence
of polyglucosamine-glyoxylate and HA dissolved in the mixture
solution.
[0038] FIG. 4 shows the ease injectability of the mixture of
polyglucosamine-glyoxylate and HA.
[0039] FIG. 5 is a schematic illustration showing the formation of
complex precipitate upon the mixing of polyglucosamine solution
with HA solution.
DETAILED DESCRIPTION
[0040] It is provided a method and composition which allows direct
formation of gel-like solutions of polyglucosamine at neutral
pH.apprxeq.7 to 8, eliminating the need of prior dissolution of
polyglucosamine in acidic environment.
[0041] The present description is based on the finding that the
specific interaction of polyglucosamine polymers with a glyoxylate
aqueous solution (at pH.apprxeq.7 to 8), allows direct formation of
neutral gel-like solutions, eliminating the need of prior
acidification and subsequently neutralization. The gel-like
solutions described here have the ability to form clear and
homogeneous liquid mixtures, free from any precipitation, with a
negatively charged polyelectrolyte such as a hyaluronate (HA)
solution.
[0042] Polyglucosamine polymers are linear amino-polysaccharides
composed of D-glucosamine and N-acetyl-D-glucosamine units linked
by (1-4) glycosidic bonds (see FIG. 1). Polyglucosamine contains
free amine (--NH.sub.2) groups and may be characterized by the
proportion of N-acetyl-D-glucosamine units and D-glucosamine units,
which is expressed as the degree of deacetylation (DDA) of the
fully acetylated polymer chitin. The non-solubility of
polyglucosamine polymers at physiological pH constitutes the main
technical difficulty limiting their use in a solution state. Thus
typically, dissolution of polyglugosamine is achieved via the
protonation of amine groups in acidic aqueous solutions. The
resulting solutions have a pH ranging from 3.0 to 5.5 and if
neutralized, the polymer remains soluble up to a pH near 6.2.
Beyond this pH value, further deprotonation of the amino-groups
reduces inter-chain electrostatic repulsion and allows attractive
forces of hydrogen bonding, hydrophobic and van der Waals
interactions to cause polymer precipitation.
[0043] Glyoxylate is the conjugate base of glyoxylic acid, an
environmentally and toxicologically safe biochemical. It is
generally highly versatile for chemical synthesis and is therefore
produced in high market volumes. Glyoxylate is an intermediary in
glyoxylate cycle, which allows microorganisms, such as bacteria,
fungi and plants to convert fatty acids into carbohydrates.
Glyoxylate is also a by-product in the biosynthesis of amide
peptides.
[0044] The composition described herein consists on the dispersion
of polyglucosamine into a glyoxylate aqueous solution (at
pH.apprxeq.7-8), where specific interaction between
polyglucosamine's amino groups and glyoxylate anions allows the
formation of neutral gel-like solution (see FIG. 2a). Indeed, the
amino groups of polyglucosamine react with the aldehyde function of
glyoxylate to form imine bond and water. This reversible reaction
is schematised as follow.
##STR00001##
[0045] In one aspect, the present application proposes to take
benefit from the reversibility of imine bond to design injectable
polyglucosamine-glyoxylate gel-like solutions. When such solutions
are injected in vivo, the reverse reaction allows the progressive
deposition of original polyglucosamine at the injection site.
[0046] In another aspect, the resulting neutral
polyglucosamine-glyoxylate solutions have the particularity to be
mixed with solutions of negatively charged polyelectrolyte, such as
hyaluronate and alginate solutions, to form homogeneous and clear
liquid mixtures, free from any precipitate (see FIGS. 2b and 3).
The absence of precipitation is due to the very low content of
charged amino groups. As seen in FIG. 5, ionic bonds are formed for
example when sodium glyoxalate has been replaced either by
glyoxylic acid or by hydrochloride acid, causing precipitation (see
FIGS. 2c and d). I
[0047] In polyglucosamine-glyoxylate solutions where the pH is
between 7 and 8, less than 17% of un-reacted amino groups can be
positively charged or protonated. In addition, it can be estimated
that more than 50% of amines should be imine-linked to glyoxylate
in order to form polyglucosamine gel-like solutions. In contrast,
for polyglucosamines dissolved in acids, the pH is usually between
4.5 and 5.5. At this level of pH, more than 90% of amino groups are
protonated, and then if such solutions are mixed to anionic
polyelectrolyte solutions, such as HA or alginate solutions,
polyelectrolyte complexes are instantaneously formed.
[0048] Typical polyglucosamines include, for example, chitin,
chitosan, and polyglucosaminoglycans which are copolymers of
N-acetylglucosamine and various glycan sugars, e.g. chondroitin,
heparin, keratan and dermatan.
[0049] Particularly, chitosan is an amino polysaccharide obtained
by partial to substantial alkaline N-deacetylation of chitin also
named poly(N-acetyl-D-glucosamine), which is a naturally occurring
biopolymer found in exoskeleton of crustaceans, such as shrimp,
crab and lobster shells. Chitosan contains free amine (--NH.sub.2)
groups and may be characterized by the proportion of
N-acetyl-D-glucosamine units and D-glucosamine units.
[0050] Chitosan is thus recognized as a biodegradable,
biocompatible, antibacterial and hemostatic biopolymer that is able
to promote wound healing, drug absorption, and tissue
reconstruction. Chitosan also has been widely explored in numerous
cosmetic and pharmaceutical applications. Therefore, considering
the great potential of chitosan, there is a continuous need to
improve the properties of known thermosensitive chitosan hydrogels
which are still considered as very promising for a wider range of
biomedical applications.
[0051] In vivo, chitosan compositions and materials have been
tested in various animal models and through several administration
routes. Chitosan has been safely studied in mouse models
(immunogenicity), rat models, guinea pig models, and rabbit models
(sub acute toxicity). No "significant toxic effects" of chitosan
were noted in acute toxicity tests in mice, no eye or skin
irritation in rabbits and guinea pigs respectively. In the same
study it was also concluded that chitosan was not pyrogenic.
Exposure of rat nasal mucosa to chitosan solutions at 0.5% (w/v)
over 1 h caused no significant changes in mucosal cell morphology
compared to control. From most studies reported it appears that
chitosan shows minimal toxic effects and this justifies its
selection as a safe material in drug delivery. Chitosan
.beta.-glycerophosphate systems have been investigated in vitro, in
vivo in animal models and in humans, and have shown a safe and
non-toxic profile (Hirano et al., 1991, Agric. Biol. Chem., 55:
2623-2625; Ono et al., 2000, J. Biomed. Mater. Res., 49: 289-295;
Azad et al., 2004, J. Biomed. Mater. Res. B Appl. Biomater., 69:
216-222; Ishihara et al., 2001, Wound Repair Regen., 9: 513-52; and
Ilium et al., 1994, Pharm. Res., 11: 1186-1189).
[0052] In humans, a phase two clinical trial involving the
percutaneous injection of chitosan-.sup.166holmium complex, for the
treatment of hepatocellular carcinoma, on patients with poor
surgical prospects, reported safe and efficacious results. The
effects of chitosan have been investigated on eighty patients with
renal failure undergoing long-term stable haemodialysis treatment.
The patients were tested after a control treatment period of 1
week. Half were fed 30 chitosan tablets (45 mg chitosan/tablet)
three times a day. Ingestion of chitosan effectively reduced total
serum cholesterol levels (from 10.14+/-4.40 to 5.82+/-2.19 mM) and
increased serum haemoglobin levels (from 58.2+/-12.1 to 68+/-9.0 g
L-1). During the treatment period, no clinically problematic
symptoms were observed. The results suggest that chitosan might be
an effective treatment for renal failure patients, although the
mechanism of the effect should be investigated further.
[0053] Chitosan was also administrated intranasal to deliver
morphine in patients following orthopedic surgery, and was shown to
offer a safe and less invasive alternative to intra venous (IV)
morphine. An clinical and pharmacokinetic study for a drug delivery
system (DDS) of gentamycin-loaded chitosan bar were carried out
with the purpose to evaluate its efficacy and giving further data
for its clinical applications. Eighteen cases of chronic
osteomyelitis were treated by surgical necrectomy with implantation
of gentamycin-load chitosan bar in the prepared bone cavity. All of
the eighteen cases were followed up for 24.8 months (in a range of
6-34 months) sixteen patients received initial cure and without any
recurrence. So, it could be concluded that the gentamycin-loaded
chitosan DDS was a simple and effective method for the treatment of
chronic osteomyelitis without the necessity to carry out a second
operation to remove the drug carrier.
[0054] In China, on twelve patients, chitosan was observed to
safely prevent or reduce elbow adhesion after elbow arthrolysis. It
was investigated again in humans to prevent knee adhesion following
patella operation (Kim et al., 2006, Clin. Cancer Res., 12:
543-548; Jing et al., 1997, J Pharm Pharmacol., 49(7): 721-723;
Stoker et al., 2008, Pain Med., 9: 3-12; and Chen et al., 1998,
Chinese Journal of Reparative and Reconstructive Surgery, 12:
355-358).
[0055] Several clinical trials involving chitosan compositions or
materials for drug delivery or medical implant purposes are ongoing
(recruiting) or terminated in the United States. Chitosan materials
are, or have been, clinically studied in patients for the
management of difficult spontaneous epistaxis and to evaluate its
healing effect on nasal mucosa, to investigate the safety and
efficacy of hemostasis of the dressing for use in dental surgical
procedures, to test a chitosan pad after diagnostic percutaneous
coronary angiography as an adjunct to manual compression to better
control vascular access site bleeding and reduce
time-to-hemostasis, to investigate a chitosan composition as a
safe, effective debridement of chronic wounds in the operating room
and inpatient ward settings and to minimize bacterial
re-colonization of wounds, to investigate the therapeutic benefits
of using a chitosan composition for the wound repair of diabetic
neuropathic foot ulcers, to compare the efficacy of a chitosan
composition versus conventional treatment in the treatment of
Diabetic Neuropathic Foot Ulcer, to investigate a new chitosan
derivative for reducing the symptoms associated with Dry Eye
Syndroma, and to investigate whether the treatment of damaged
cartilage in the knee with a chitosan composition will increase the
amount and quality of cartilage repair tissue when compared with
microfracture alone. Moreover, chitosan materials are, or have
been, clinically studied in patients to determine if chitosan, a
short-chained chitosan with a molecular weight of 40 kDa, is safe
and effective in lowering LDL-cholesterol levels in patients with
mild to moderately elevated cholesterol levels (drug), and to
compare safety and immunogenicity of two dosage levels of Norwalk
VLP Vaccine with chitosan adjuvant/excipients.
[0056] Hyaluronan (also called hyaluronic acid or hyaluronate or
HA) is a naturally occurring linear polysaccharide belonging to the
class of non-sulfated glycosaminoglycans (see FIG. 1). Its
repeating unit is a disaccharide composed of
.beta.-1,4-N-acetyl-D-glucosamine and .beta.-1,3-D-glucuronic acid.
HA is found in cartilage, synovial fluid and skin tissue. HA is
used in a variety of applications including osteoarthritis,
cosmetics, ophthalmology, therapeutics delivery, wound healing and
tissue engineering. Because HA is water-soluble and is degraded and
eliminated rapidly in vivo, the potential application for HA in
biomedical purposes have been somewhat limited.
[0057] HA is known to perform a number of functions in man and
other animals including the lubrication of the joints, the
maintenance of the gel-like character of the vitreous humor of the
eye and the contribution to the ground substance around cells where
it functions as an inter-cellular lubricant and flexible cement. HA
is well accepted by the ophthalmic community as a compound that can
protect biological tissues or cells from compressive forces.
Accordingly, HA has been proposed as a component of a viscoelastic
ophthalmic composition for cataract surgery. HA has been used to
maintain the hydration and condition of the eye during various
surgical procedures such as corneal grafts. More recently, because
of its joint lubricant function, investigations have been directed
in an attempt to use HA to alleviate the inflammatory joint
conditions such as arthritis. In animals such as the horse, it is
currently used as a method of treatment of inflammatory joint
conditions.
[0058] In addition, because it is known to be a constituent of the
ground substance of cells, HA is being incorporated into various
cosmetic preparations for the skin. In this role it is proposed
that the addition of HA to the skin is able to raise the level of
HA present in the cells coats in the dermal layers thereby
improving the condition of the skin. HA is also applied to the skin
for healing wounds, burns, skin ulcers, and as a moisturizer. There
is also a lot of interest in using hyaluronic acid to prevent the
effects of aging.
[0059] It is provided a homogeneous liquid combination of
polyglucosamine-glyoxylate with HA which can be used for example in
order to significantly increase the residence time of the later in
vivo. Indeed, when such combination is injected in vivo, the
glyoxylate species are released from polyglucosamine-glyoxylate
through the reverse reaction, and thus the cationic charge density
of polyglucosamine is increased (see FIG. 3). This results into
stronger attractions with HA, thus preventing its rapid elimination
and enhancing its retention time.
[0060] The present disclosure will be more readily understood by
referring to the following examples which are given to illustrate
embodiments rather than to limit its scope.
EXAMPLE I
Preparation of a Mixture of Polyglucosamine-Glyoxylate and
Hyaluronate
[0061] The following examples describe the preparation of
homogeneous and clear mixture of polyglucosamine with hyaluronate
(HA) in presence of sodium glyoxylate.
[0062] A suspension of 0.1110 g of polyglucosamine (80%) in 5 mL of
water is added with 0.0739 g of sodium glyoxylate. A gel-like
solution is formed within 1 hour at a physiological pH.
[0063] Afterwards, 5 mL aqueous solution (2%) of hyaluronic acid
sodium salt (HA) was added and thoroughly mixed with the gel-like
solution of polyglucosamine/glyoxylate. The resulting mixture is
viscous and clear homogeneous solution free from any precipitate as
can be seen in FIG. 2a.
[0064] Further, a mass of 0.2007 g of HA is added to a suspension
of 0.1091 g of polyglucosamine (80%) in 10 mL of water, under
stirring. The stirring is continued until complete dissolution of
HA, which results in viscous solution where polyglucosamine
particles are homogeneously dispersed. Then, 0.0720 g of sodium
glyoxylate is added while maintaining stirring for about 3 to 4
hours until entire solubilisation of polyglucosamine. The resulting
mixture consists of clear and homogeneous viscous solution as shown
in FIG. 2b. The pH of the mixture is in the physiological range,
between 7 and 8. Both mixtures prepared can be easily injectable as
shown in FIG. 4.
EXAMPLE II
Preparation of a Mixture of Polyglucosamine-Glyoxylic acid with
HA
[0065] A volume of 10 mL of water is added to 0.1088 g of
polyglucosamine powder under stirring to create a homogeneous
dispersion, to which a mass of 0.2017 g of HA is then added. The
stirring is maintained for about 2 to 3 hours until complete
dissolution of HA and viscous dispersion is obtained. Then, 0.72 mL
of glyoxylic acid solution (1M) is added and the stirring
continued. The resulting mixture turned into white due to the
presence of white hydrated precipitate, as shown in FIG. 2c,
indicating an instantaneous formation of a complex between
polyglucosamine and HA. Such result can be expected by any skilled
person in the art because polyglucosamine and HA are two
polyelectrolytes of opposite charges.
EXAMPLE III
Preparation of a Mixture of Polyglucosamine-HCl with HA
[0066] A mass of 0.1092 g of polyglucosamine is dissolved in 5 mL
of HCl solution (77mM) and then mixed with 5 mL of HA aqueous
solution (2%). The mixture turned instantaneously to a white
hydrated precipitate indicating the formation of a complex between
positively polyglucosamine and negatively charged Hyaluronate (HA).
With time the precipitate clearly separate from the solution as can
be seen in FIG. 2d.
[0067] While the description has been described in connection with
specific embodiments thereof, it will be understood that it is
capable of further modifications and this application is intended
to cover any variations, uses, or adaptations of the disclosure,
including such departures from the present disclosure as come
within known or customary practice within the art to which the
disclosure pertains and as may be applied to the essential features
hereinbefore set forth, and as follows in the scope of the appended
claims.
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