2.3. Preparation of unloaded mini-capsules
Mini-capsules were prepared by ionic gelation. In particular
500ml of a CaCl2 (0.75% w/w)/CS aqueous mixture was dropped
with a syringe needle (32 G: 0.26 mm Ø 4 mm) in 50 ml of an
aqueous PEC/HA mixture. To prepare CS solution, an exact amount
of glutamic acid (to obtain a 1:1 molar ratio with chitosan
deacetylated amino groups) was added to distilled water before
chitosan dispersion. Mini-capsules were immediately separated by
vacuum filtration, freeze-dried overnight (Heto DRY WINNER1,
Analitica De Mori, Milan, Italy) and then characterized.