Synthesis of cross-linked chitosan-based hydrogel in order to investigation of loading and release rate of hydroquinone

Hydrogels are hydrophilic polymers with a three-dimensional network that can absorb and store water and aqueous solutions. These materials are initially anhydrous. But they can absorb aqueouse solution several times greater than hydrogel own weight. There are some pores in the hydrogels that can trap the drug and subsequently release the drug through a mechanism that depends on the drug distribution factor. Hydrogel-based drug delivery systems operate on the basis of a kind of stimulus. This can be a physical or chemical stimulus. Physical stimuli, include temperature, current, light, etc. While the chemical stimulant is related to PH, solvent, etc. The small change in ambient conditions such as pH causes large changes in hydrogel structure and its reversibility [1-2]. In this study, chitosan-based hydrogel was cross-linked with glutaraldehyde and the hydroquinone was trapped as a drug into the hydrogel [3]. In order to release the drug, the cross-linked polymer was inserted in the solution at pH 1-12. The concentration of released hydroquinone subsequently was determined using spectrophotometry. The results show that the release of hydroquinone in acidic pHs is greater. This is due to, the amount of water absorption in acidic pHs is higher than that of basic pHs.