The electro-responsive drug delivery from salicylic acid -loaded polyacrylamide hydrogels

The release mechanisms and the diffusion coefficients of salicylic acid -loaded polyacrylamide hydrogels were investigated experimentally by using a modified Franz-Diffusion cell at the temperature of 37 $^{0}$C to determine the effects of crosslinking ratio and electric field strength. The fabricated hydrogels retain their physical shapes and sizes during the experiments along with data reproducibility. A significant amount of salicylic is released within 48 hours from the hydrogels of various crosslinking ratios with and without electric field; the release profile follows the Q vs. t$^{1/2}$ relationship. Diffusion coefficients, as determined from the Higuchi equation, increase with electric field strength and reach maximum values at electric field strength of 0.1 V due to the electrophoresis of salicylic drug and become saturated at electric field strengths between 0.5 -- 10 V.