The equilibrium water absorption was determined through the
immersion of pre-weighted cross-linked film samples with 20 mm
of diameter and thickness in a range of 54.4–66.0 m, into 20 mL
of solution during 24 h. After this period, films were collected from
the medium, the excess of water was removed with a filter paper,
and the hydrated weight measured. In this test, solutions with different
values of pH were used: (i) 0.1 M HCl solution at pH 1.0
simulating the gastric fluid, (ii) acetate buffer at pH 5.5 (10 mM)
simulating the pH ofthe skin, and (iii) SBF solution at pH 7.4 (50 mM
of trishydroxylaminomethane and 45 mM hydrochloric acid),