De Marco I., Baldino L., Cardea S., Reverchon E., 2015, Supercritical Gel Drying for the Production of Starch Aerogels for Delivery Systems, Chemical Engineering Transactions, 43, 307-312.
Supercritical fluids based processes were frequently proposed to realize new kind of supports to deliver poor water-soluble drugs. In some cases, nanostructured aerogels were used as substrates. The matrices constituting the aerogel have to present a high porosity and a high surface area. Different natural and synthetic polymers were used in form of aerogels. Natural polymer-based materials are preferable for their renewability and for environmental reasons; among them, starch is the second most abundant after cellulose and it is attractive for its low cost. In this work, different sources starches (maize, potato and wheat) aerogels were produced using a supercritical carbon dioxide based process. First, a gel is formed by an aqueous solution (hydrogel), then water is replaced by ethanol to form an alcogel; finally, a supercritical gel-drying step is proposed to form the aerogel. The different sources starches were processed and characterized from a macroscopic and a microscopic point of view. The analyses confirmed that the supercritical gel drying process is suitable to form polymeric nanostructured matrices that can be used for delivery systems.
