Influence of Crosslinker on Pullulan Hydrogel for Iontophoresis Controlled Transdermal Aspirin Release

Nowadays, transdermal drug delivery system (TDDS) has been developed continuously because it solves the problem of drug level inconsistencies in the blood and prevents the drug from being destroyed in the digestive tract. However, the limitations of TDDS are the low release rate of the patch and difficult penetration of the drug to the skin. Therefore, this research aims to study drug release behavior of aspirin with and without applied electrical potential for controlled drug release from the pullulan hydrogel patch using sodium trimetaphosphate and citric acid at various concentrations as the crosslinker. The pullulan hydrogel patches prepared by the solvent casting method were studied the release behavior by using a modified franz diffusion cell with containing pH 5.5 and 7.4 buffer solution at 37 ◦C for 2 h. The amount of drug release was compared with various electrical potentials as 0, 0.5, 1, 3, and 5 V. The aspirin release behavior from pullulan hydrogel was a Non-Fickian mechanism meaning that the aspirin was released via concentration gradient combined with swelling behavior of drug matrix. The amount of drug release and releasing rate was decreased with increasing the crosslinking ratio because of the lower the swelling behavior of matrix. In addition, the applied electrical stimulation enhanced the amount of drug release and releasing rate. The maximum release of aspirin is approximately 25% within 9 min from the hydrogel patch using sodium trimetaphosphate as a crosslinker and a 5 V which is higher than that of 0 V as 16% within 12 min.