Investigation of electrical stimuli for controlled drug release from chitosan DDS

August 2013

Controlled drug release is crucial for targeted implantable smart drug delivery system (DDS). In this work, simulations and experiments are conducted to demonstrate drug release mechanism using electrical stimulus. For dyed chitosan beads (diameter 500um to 900um), a surface acoustic resonator (SAW) chip cavity which has interdigited electrode on quartz surface was used to provide electrical stimulus. Printed circuit board (PCB) and sputter coated interdigited electrodes were used to provide electrical stimulus on the chitosan film. Two simulation models (SAW resonator and chitosan film) are developed to explain the physical phenomena of drug release using finite element method (FEM). It is found that drug delivery is nonlinearly increased with applied electric field to the electrodes. The AC electro-kinetic (ACEK) force generated from electrical excitation is a factor influencing this phenomenon. Temperature rise was not significant as demonstrated in both simulations and experiments. Different control and stimulus experiments were performed to show the concepts of dye release from micro beads using electrical stimuli. Dye release has been identified visually for these experiments. Chitosan films loaded with green food coloring were also fabricated to demonstrate the drug release. Experiments were conducted with different electric fields and frequencies on chitosan fi?lm. The spectral absorbance of treated solution after the experiment is measured using a spectrophotometer to quantify the dye release. Verification of the dye release with increased applied voltage was statistically proven with 99% level of significance. This study has shown that application of electric field can be a potential candidate for controlled DDS using both chitosan micro-beads/films.