چکیده (انگلیسی):

The aim of this study was to analyze the process of tablet
formation and the properties of the resulting tablets for 3 Ndeacetylated
chitosans, with a degree of deacetylation of
80%, 85%, or 90%. Material properties, such as water content,
particle size and morphology, glass transition temperature,
and molecular weight were studied. The process of
tablet formation was analyzed by 3-D modeling, Heckel
analysis, the pressure time function, and energy calculations
in combination with elastic recovery dependent on maximum
relative density and time. The crushing force and the
morphology of the final tablets were analyzed. Chitosans
sorb twice as much water as microcrystalline cellulose
(MCC), the particle size is comparable to Avicel PH 200, a
special type of MCC, the particles look like shells, and the
edges are bent. Molecular weight ranges from 80 000 to
210 000 kDa, the glass transition temperature (Tg) was not
dependent on molecular weight. The chitosans deform
ductilely as MCC; however, plastic deformation with regard
to time and also pressure plasticity are higher than for MCC,
especially for Chit 85, which has the lowest crystallinity and
molecular weight. At high densification, fast elastic decompression
is higher. 3-D modeling allowed the most precise
analysis. Elastic recovery after tableting is higher than for
MCC tablets and continues for some time after tableting.
The crushing force of the resulting tablets is high owing to a
reversible exceeding of Tg in the amorphous parts of the
material. However, the crushing force is lower compared
with MCC, since the crystallinity and the Tg of the chitosans
are higher than for MCC. In summation, chitosans show
plastic deformation during compression combined with high
elasticity after tableting. Highly mechanically stable tablets
result.