Preparation of silk sericin beads using LiCl/DMSO solvent and their potential as a drug carrier for oral administration

Silk sericin (SS) was fabricated into beads using LiCl/DMSO solution as a solvent. Up to 30 % (w/v) of SS could be dissolved within 3 hours, and the shape of solidified SS depends on the concentration of SS. Ethanol was the best coagulant among alcohols, making beads with suitable mechanical strength for further application. SS beads swell more at a pH above the isoelectric point (pl) than below the pl. The pH and the presence of an enzyme greatly affect the dissolution rate of SS beads. Whereas only 10 % of SS beads were dissolved at pH 2.2 in the presence of pepsin, more than 45 % of SS beads were dissolved at pH 7.4 in the presence of trypsin. The release of drug was suppressed in a stomach-like environment while promoted in an intestine-like environment.