When the fraction of acetylated amine groups is reduced
to 40-35%, the resultant co-polymer, (1 → 4)-2-amine-2-
deoxy-β-D-glucan and (1 → 4)-2-acetamide-2-deoxy-β-Dglucan,
is then referred to as chitosan. Chitosan is primarily
characterized by its molecular weight (MW) and the degree
of acetylation (DA). Commercially chitosan is available
with > 85% deacetylated units (DA < 15%), and molecular
weights (MW) between 100 and 1000 kDa. There is no a
specific standard to define MW, but it is accepted that Low
MW < 50 kDa, Medium MW 50 – 150 kDa, and High MW
> 150 kDa