Surface Cross-Linked Poly (Vinyl Alcohol) Hydrogel for Colon Targeted Drug Release

A series of surface cross-linked PVA hydrogels (previously bulk cross-linked with maleic anhydride) were prepared for different cross-linker (glutaraldehyde) concentration. FTIR-ATR study revealed the cross-linking reaction. Surface cross-linking results in contraction of pores and increase in hydrophobicity, pore tortuosity around the surface of the membrane. As a result swelling, drug release decreases with increasing glutaraldehyde concentration. After surface cross-linking swelling of the hydrogels in simulated gastric fluid (SGF) further decreased to attain half of the value as observed for only bulk cross-linked membranes. Surface cross-linking has improved the colon-targeted release characteristics of the drugs from the PVA hydrogels.