Iontophoresis delivers medication through the skin using what mechanism?

• A. Mechanical pressure
• B. Electrical current
• C. Thermal energy
• D. Acoustic waves

Answer: (B)

Iontophoresis works by using an electrical current to move charged drug ions through the skin. The applied current creates a potential gradient across the skin, so ions in the delivery solution migrate into and through the skin (electrophoresis), with the flow often aided by the solvent movement caused by the electric field (electroosmosis). This mechanism relies on charge and an electric field, not on physical pushing, heat, or sound waves.

That’s why mechanical pressure isn’t the driver here—ion movement isn’t achieved by pushing tissue or drug via forceful contact. Thermal energy would affect tissue permeability in other ways, not by electromigration of ions. Acoustic waves rely on ultrasound to enhance penetration, which is a different method altogether.