Preparation and characterization of pH-responsive sodium alginate/humic acid/konjac hydrogel for L-ascorbic acid controlled release

In the current work, a mixed hydrogel of sodium alginate (SA), humic acid (HA) and konjac gum (KGM) was studied by ionic coordination of Ca2+. The SA/HA/KGM hydrogel was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The ratio of SA/HA/KGM to the amount of Ca2+ was investigated by the swelling property of the gel. The pH sensitivity of the SA/HA/KGM gel was investigated using the swelling properties of the gel under different pH conditions. In vitro drug release indicated that the formed SA/HA/KGM hydrogel had a good release effect on L-AA in different pH environments, and the encapsulation and drug loading of the drug were greatly improved.