Biomedical Engineering Reference
In-Depth Information
5.2.6 Arabinogalactan
Arabinogalactan is a long, highly branched natural polysaccharide
composed mostly of galactose and arabinose. Arabinogalactan is
extracted mainly from the Larix tree and is available at 99.9% purity
with reproducible Mw and physicochemical properties [44]. The
unusual water solubility (70% w/w in water), biocompatibility,
biodegradability, and ease of drug conjugation in an aqueous medium
make arabinogalactan attractive as a potential drug carrier [44].
5.2.7 Pullulan
Pullulan is neutral, homopolysaccharide consisting of α-(1,6)-
linked maltotriose residues (Figure 5.1). It is produced from starch
primarily by strains of the fungus
Aureobasidium pullulans
[45].
Pullulan's structure unique linkage pattern contributes to exceptional
physiochemical properties such as adhesiveness, water solubility,
and relatively low viscosity upon dissolving in water. Therefore,
pullulan and its derivatives have been used industrially in foods and
pharmaceuticals [45].
OH
OH
OH
OH
OH
OH
OH
OH
O
O
OH
OH
O
O
O
NH
O
NH
OH
OH
O
O
O
O
O
O
O
OH
O
OH
HO
HO
O
O
O
O
O
H
OH
HO
HO
O
O
O
O
O
O
HO
HO
O
O
HO
HO
O
O
O
O
HO
HO
NH
2
NH
2
NH
NH
HO
HO
O
O
OH
OH
O
O
O
O
n
Chitosan
n
Chitosan
m
m
n
n
m
m
n
n
Hyaluronan
Hyaluronan
Chitosan
Chitosan
Hyaluronan
Hyaluronan
Alginate
Alginate
Alginate
Alginate
OH
OH
OR
1
OR
1
OR
2
OR
2
O
O
OH
OH
O
-
O
-
O
O
OR1
OR1
O
O
O
O
O
O
HO
HO
O
O
O
O
O
O
O
O
O
O
O
O
OH
OH
O
O
O
O
HO
HO
OH
OH
NH
NH
HO
HO
HO
HO
OH
OH
O
O
R1O
R1O
R2HN
R2HN
O
O
O
O
HO
HO
n
n
OH
OH
O
O
O
O
n
n
Chondroitin Sulfate
Chondroitin Sulfate
n
n
Chondroitin Sulfate
In Chondroitin-4-Sulfate R
1
=SO
3
H and R
2
=H
In Chondroitin-6-Sulfate R
1
=H and R
2
=SO
3
H
Chondroitin Sulfate
In Chondroitin-4-Sulfate R
1
=SO
3
H and R
2
=H
In Chondroitin-6-Sulfate R
1
=H and R
2
=SO
3
H
Amylose
Amylose
Amylose
Amylose
Heparin
In the major repeating unit R
1
,R
2
=SO
3
H
Otherwise, R
1
=H or SO
3
H and R
2
=H, SO
3
HorCOCH
3
Heparin
In the major repeating unit R
1
,R
2
=SO
3
H
Otherwise, R
1
=H or SO
3
H and R
2
=H, SO
3
HorCOCH
3
In Chondroitin-4-sulfate R1=SO3HandR2=H
In Chondroitin-4-sulfate R1=SO3HandR2=H
Heparin
Heparin
In Chondroitin-6-Sulf ate R
1
=H and R
2
=SO
3
H
In Chondroitin-6-Sulf ate R
1
=H and R
2
=SO
3
H
In the major disaccharide repreating unit R
1
and R
2
=SO
3
H
Otherwise, R1=H or SO3HandR2=H, SO3HorCOCH3
In the major disaccharide repreating unit R
1
and R
2
=SO
3
H
Otherwise, R1=H or SO3HandR2=H, SO3HorCOCH3
OH
OH
O
O
O
O
O
O
HO
HO
O
O
OH
O
OH
O
HO
HO
HO
HO
OH
OH
HO
HO
OH
O
OH
O
O
O
HO
HO
O
O
HO
HO
OH
OH
HO
HO
OH
O
OH
O
O
O
OH
O
OH
O
HO
HO
O
O
HO
HO
OH
OH
OH
O
OH
O
OH
O
OH
O
n
n
O
O
Dextran
Dextran
Dextran
Dextran
HO
HO
OH
OH
OH
-Cyclodextrin
OH
-Cyclodextrin
O
n
O
n
Pulluan
Pulluan
-Cyclodextrin
-Cyclodextrin
Pullulan
Pullulan
Figure 5.1
Chemical structures of polysaccharides.
β
-Cyclodextrin structure
obtained with permission from http://www.chemblink.com
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