In iontophoresis, which factor most directly determines the current density delivered to tissue?

• A. Current Strength
• B. Electrode Material
• C. Temperature
• D. Drug Concentration

Answer: (A)

The main idea is that current density is the amount of current delivered per unit area of tissue. In iontophoresis, the current density follows J = I/A, so the current strength being applied is what directly sets how much current per square centimeter reaches the tissue. If you keep the contact area fixed, increasing the current increases the density proportionally, while changing the area changes density inversely.

Other factors can influence how easily current or ions move (like electrode impedance, tissue resistance, or the drug’s diffusion), but they don’t establish the density itself. Electrode material and temperature may alter the actual current reaching tissue by changing resistance, and drug concentration affects transport rate, but the quantity of current per area is determined by the applied current.