Electric field-induced release of sulfosalicylic acid from poly(vinyl alcohol) hydrogel

This study evaluated and characterized the use of poly (vinyl alcohol) (PVA) hydrogels as matrix/carriers for drug in the electrically controlled drug delivery system. The drug-loaded PVA hydrogels were prepared by solution casting using sulfosalicylic acid as the model drug and glutaraldehyde as the crosslinking agent. The mesh or pore size of the PVA hydrogels were determined using scanning electron microscopy (SEM). The mesh or pore size of PVA hydrogels decreased with increasing crosslinking ratio. The release mechanisms and the diffusion coefficients of drug from hydrogels were studied using a modified Franz-diffusion cell in acetate buffer at pH 5.5 and at the temperature of 37 degC for 48 hours, in order to determine the effects of crosslinking ratio and electric field strength. The amount of released drug was analyzed by UV-visible spectrophotometry. The plots of the amount of drug released as a function of square root of time showed a linear relationship. The diffusion coefficients of drug in PVA hydrogels decreased with increasing crosslink ratio. Moreover, the diffusion coefficients of drug in the PVA hydrogels depended critically on electric field strength between 0-5 V.