Research on Preparation of the Poly (vinyl alcohol) (PVA)/Dextran Blend Hydrogel and its Drug Release

Objective: To prepare a blend hydrogel based on a physically cross-linked poly (vinyl alcohol) (PVA)/Dextran by repetitive freeze-thaw procedures and investigate its drug release behavior. Methods: Insulin-loaded blend hydrogel was created by freezing an aqueous solution of PVA/Dextran/Insulin at-20 ℃ for 8 h and thawing it at room temperature for 4 h (repeat the freeze-thaw cycle several times as needed). Insulin release kinetics from blend hydrogel was investigated by RP-HPLC in vitro. Results: Release profile of Insulin followed Higuchi equation. As PVA/Dextran ratio dropped from 100/0 to 80/20, the rate of Insulin release increased markedly, and the maximum Insulin depletion increased from 45 % to 65 % of the total loading. As the freeze-thaw cycle increased from 2 to 6, the time for Insulin release to cease increased from 24 h to 45 h, and the maximum depletion decreased from 70 % to 50 % of the total loading. The increase of release medium temperature could enhance the release rate. Conclusions: Insulin-loaded blend hydrogel made of PVA and Dextran could offer sustained release of Insulin. PVA/Dextran blend hydrogel is a potentially useful system as drug delivery carrier.