Which of the following is NOT a characteristic of iontophoresis?

• A. Requires direct current
• B. Delivers medications through the skin
• C. Uses ionizable compounds
• D. Uses alternating current

Answer: (D)

Iontophoresis relies on a steady direct current to create an electric field that drives charged drug ions through the skin, enabling transdermal delivery. The current provides unidirectional force on the ionized molecules, guiding them from the electrode toward and into the skin, and can also help move solvent via electroosmosis for a more controlled flux. Because of this, delivering medications through the skin and using ionizable compounds are inherent features of the method.

Using alternating current would reverse polarity repeatedly, causing ions to move back and forth rather than delivering a steady, net amount into or through the skin. This would drastically reduce or negate effective transdermal transport, so alternating current is not a characteristic of iontophoresis.