Controlled delivery of drug from pH sensitive chitosan/poly (vinyl alcohol) blend

The blends of chitosan (CS) and poly(vinyl alcohol) (PVA) react with tetraethoxy silane (TEOS) to give network structure and their selective crosslinking give hydrogel properties. The swelling properties against different media are changed by varying the amount of PVA in CS/PVA blend. The degree of swelling in water is decreased with increasing amount of PVA. The most significant behavior of these blends is their response against pH, exhibiting low swelling in acidic and basic pH conditions and maximum swelling at neutral pH. This unique behavior along with the biocompatibility of the components made them suitable for oral delivery of enzymes and medicines. Dexamethasone has been selected as a model drug. The released profile of dexamethasone loaded CS/PVA complex showed 9.37% of drug release over a period of 2 h in simulated gastric fluid and its transfer to simulated intestinal fluid showed consistent release of remaining drug up to 7 h.