Angiotensin II and its antagonists were selected for in vitro absorption studies of iontophoresis. The investigated factors include the solution effects and the electricity effects. In the solution, drug concentration, buffer concentration, and pH values of the solution were studied. Current density, waveform, duty cycle and frequency of the electricity effects were also explored. The hydrophobicity of angiotensin II and its antagonists were considered in the comparison of the absorption of porcine skin at different pH value of buffer solution. From the experimental results, the pH value of buffer solution and the current density play a profound role of the absorption of the porcine skin during iontophoresis. The hydrophobic angiotensin II antagonist has higher absorption than the hydrophilic peptide, and the phenomenon is more pronounced in lower pH value. The porcine skin acted as an electric capacitor and an opposite voltage was observed when the electrical field was applied.
JOURNAL OF THE CHINESE INSTITUTE OF CHEMICAL ENGINEERS