Investigation of chemically modified inulin as encapsulation material for pharmaceutical substances by spray-drying

The application of inulin as a drug carrier system for dexpanthenol in particles prepared by spray-drying was investigated in this research. First, inulin was chemically modified by esterification of free hydroxyl groups with acetic anhydride and propionic anhydride. The obtained polymers were purified by precipitation and analyzed via NMR, FT-IR, SEC and DSC. In the next step, the spray-drying and particle formation of native inulin, acetylated and propionylated inulin were investigated in order to optimize the parameters. Each material delivered smooth and spherical particles with a size range from 0.7 mm to 10 mu m. Subsequently, 1% dexpanthenol was encapsulated in each material and the release behavior with respect to chemical modification was compared. The release behavior of dexpanthenol was determined using a flow through cell (USP4) with dialysis adapter for microparticles. Inulin particles released 100% dexpanthenol after 6 h, while the use of chemically modified inulin derivatives presented a prolonged drug release. After 24 h, 60% had been released from particles with acetylated inulin and only 10% from those with propionylated inulin.