Prilling and supercritical drying: A successful duo to produce core-shell polysaccharide aerogel beads for wound healing

• Alginate and pectin core-shell aerogel beads are produced by prilling and SAE duo.
• Fluid uptake is related to the high porosity of the aerogel polysaccharides matrix.
• Doxycycline is encapsulated into the pectin core and protected by alginate shell.
• Alginate/pectin ratio can be used to tailor doxycycline release rate.
• In situ formed hydrogels are suitable dressing to avoid removal trauma.

Bacterial infections often affect the wound, delaying healing and causing areas of necrosis. In this work, an aerogel in form of core-shell particles, able to prolong drug activity on wounds and to be easily removed was developed. Aerogel microcapsules consisted of a core made by amidated pectin hosting doxycycline, an antibiotic drug with a broad spectrum of action, and a shell consisting of high mannuronic content alginate. Particles were obtained by prilling using a coaxial nozzle for drop production and an ethanolic solution of CaCl2 as gelling promoter. The alcogels where dried using supercritical CO2. The influence of polysaccharides and drug concentrations on aerogel properties was evaluated. Spherical particles with high drug encapsulation efficiency (87%) correlated to alginate concentration in the processed liquid feeds were obtained. The release of the drug, mainly concentrated into the pectin core, was prolonged till 48 h, and dependent on both drug/pectin ratio and alginate concentration.