2.4. Characterization of freeze-casted tablets
A digital microscopic system (VH-Z100, Keyence) was used to
record the overview of morphology of the pores and tablets. The
structures of freeze-casted bodies were studied by using a scanning
electron microscope (Philips XL 30 ESEM). To get better SEM
images, samples for scanning microscopy examination were
mounted and coated with platinum in a sputter coater before
SEM measurement.
The crushing strengths of produced tablets (£ 16 mm,
h 10 mm) were measured with crushing force tester (TBH 30,
Erweka), then the tensile strengths were calculated from these
data and the geometrical parameters of tablets (Mitutoyo, Japan)
via the equation of Fell and Newton (Fell and Newton, 1970).
Porosities of tablets were determined by mercury porosimeter
Pascal 140 + 440 Series, Porotec. Dissolution profiles of tablets
were determined by a simple visible method. These methods were
presented in detail by Nguyen and Ulrich, 2014.
The measurements of crushing force are reproduced six times
and all the other measurements were carried out in triplicate