Influence of the Structure of Alginate-Chitosan Materials on the Kinetics of Usnic Acid Release
Natalia Gorshkova, О. С. Бровко, И. А. Паламарчук, К. Г. Боголицын
Abstract
Porous materials, cryogels and aerogels, were synthesized based on a sodium alginate–chitosan interpolymer complex via freeze-drying and supercritical drying. It was shown that the specific surface area of aerogels was approximately ten times higher than that of cryogels due to the developed mesoporous structure and amounted to 260 m2/g. The polyelectrolyte nature of the obtained materials, their dimensional stability, and their high water absorption (15 and 45 g/g for cryogel and aerogel, respectively) allowed us to use the obtained materials for sorption-application therapy. To impart antimicrobial properties, the materials were impregnated with usnic acid isolated from the lichen Usnea subfloridana, which has antibacterial activity against Escherichia coli bacteria and the microorganism species Staphylococcus aureus and Bacillus subtilis. It was shown that the minimum inhibitory concentration of usnic acid for these test cultures was 0.03 mg/mL. The resulting materials are capable of a slow release of usnic acid over 5 h, while its maximum release was 60% for aerogel and 30% for cryogel. The kinetics of usnic acid release of from both materials is adequately described by the Korsmeyer–Peppas equation.