Polysaccharide-based aerogels—Promising biodegradable carriers for drug delivery systems

Biopolymer aerogels were among the first aerogels produced, but only in the last decade has research on biopolymer and biopolymer-composite aerogels become popular, motivated by sustainability arguments, their unique and tunable properties, and ease of functionalization. Biopolymer aerogels and open-cell foams have great potential for classical aerogel applications such as thermal insulation, as well as emerging applications in filtration, oil-water separation, CO2 capture, catalysis, and medicine. The biopolymer aerogel field today is driven forward by empirical materials discovery at the laboratory scale, but requires a firmer theoretical basis and pilot studies to close the gap to market. This Review includes a database with over 3800 biopolymer aerogel properties, evaluates the state of the biopolymer aerogel field, and critically discusses the scientific, technological, and commercial barriers to the commercialization of these exciting materials.

Biopolymer Aerogels and Foams: Chemistry, Properties, and Applications.

Synthesis and characterization of thermo- and pH-responsive bacterial cellulose/acrylic acid hydrogels for drug delivery

An emerging platform for drug delivery: aerogel based systems.

Aerogel technology provides high added-value lightweight materials with outstanding textural properties (i.e., high surface area and open porosity). Aerogels are obtained from wet gels by using a suitable drying technology, usually supercritical drying process, able to avoid the pore collapse phenomenon in order to keep intact the porous texture of the wet material. In this sense, the study of the kinetic profile of the gel supercritical drying is regarded as a key aspect to be considered in the specific case of the design of aerogel-based systems. In this work, the drying profile with supercritical carbon dioxide (scCO 2 ) of alcogels (in ethanol) was determined using a customized supercritical fluid extraction equipment. The drying of alcogels from different precursors (inorganic-silica-, organic-starch-), densities (silica aerogel of densities 0.08 and 0.15 g/cm 3 ) and morphologies (cylindrical monoliths, microspheres) was studied. Depending on the nature of the gel precursor, the extent of drying (i.e., drying time duration) gave significant differences in the end textural properties of the dried gel.

Supercritical drying of aerogels using CO2: Effect of extraction time on the end material textural properties

The application of aerogels as drug delivery system was successfully demonstrated for silica aerogels previously However, being biocompatible silica matrices are not biodegradable, which is a certain disadvantage for a number of pharmaceutically oriented applications For these purposes biodegradable materials are beneficial Supercritical drying of polysaccharide gels results in highly porous biodegradable aerogel matrices with large surface areas Structural properties of the polysaccharide aerogels depend on the preparation method and chemical nature of the gel phase In this work different polysaccharide precursors (starch, alginate) were used to produce aerogels, which later on were loaded with the drugs ibuprofen and paracetamol Furthermore release kinetics was studied in vitro Thereby it has been shown that the release rate depends primary on the properties of the matrix The presented results demonstrate for the first time the high potential of polysaccharide aerogels for pharmaceutical applications

U. Guenther

Papers

Polysaccharide-based aerogels as drug carriers

Hydrophilic silica aerogels as dermal drug delivery systems--dithranol as a model drug.