As pointed out throughout this review, polysaccharides
show a variability and a versatility, associated with their complex
structures, not found in other classes of polymers. This
peculiarity allows a very wide range of applications, and
derivatizations further increase their possible uses. As a
consequence an ever increasing number of publications and
patents concern hydrogels prepared from native and derivatized
polysaccharides. Nevertheless, it should be underlined that little
has been focused on the connections of the physico-chemical
characteristics in solution and the rheological properties with the features of these polymers and how they behave at a
macroscopic level that finally determine the delivery mechanism.
Indeed, parameters such as origin, culture conditions,
percentages of minor groups on the macromolecules can
dramatically influence several properties of polysaccharides,
these factors are very seldom taken into consideration in
publications related to drug delivery. Consequently, results that
are not easily reproducible when experiments are carried out by
different authors on the same polysaccharide but from a
different origin or even different batch.
This said, this overview on polysaccharide hydrogels used
for drug delivery and closely related applications, clearly
indicates how this topic involves an ever increasing number of
research workers from all over the world leading to the
preparation and characterization of numerous new types of
hydrogels with peculiar properties that make them suitable for a
wide variety of applications in the field of pharmaceutics.