*4.1. Materials*

Polysaccharides, pectin from citrus (TCI Europe), and chitosan (Sigma Aldrich, medium molecular weight) were used for the synthesis of pectin aerogels and pectin aerogels coated with a layer of chitosan. Ethanol absolute, C2H5OH (Merck, Darmstadt, Germany) and carbon dioxide, CO2 (purity 99.5%, Messer, Ruše, Slovenia) were introduced for the solvent exchange during synthesis of gels and supercritical drying of prepared gels, respectively. Curcumin (purity ≥ 65%, Merck, Darmstadt, Germany) was used as an active substance for prepared aerogels. Chitosan was dissolved in acetic acid, CH3COOH (purity ≥ 98%, Fisher Scientific, Pittsburgh, PA, USA). Hydrochloric acid, HCl (purity 37%, Merck, Darmstadt, Germany), potassium phosphate monobasic, KH2PO4 (purity ≥ 98%, Merck, Darmstadt, Germany) and sodium hydroxide, NaOH (purity ≥ 98%, Merck, Darmstadt, Germany) were employed for the preparation of simulated gastric (SGF) and simulated intestinal fluid (SIF) for swelling and drug release studies. SGF (HCl) with pH = 1.2 was prepared by diluting 8.3 mL of 37% HCl to 1000 mL with miliQ water. SIF (phosphate buffer solution) with pH = 6.8 was prepared by mixing 250 mL of 0.2 M KH2PO4 and 112 mL of 0.2 M NaOH and diluted to 1000 mL with miliQ water.
