Iontophoresis uses which pole to introduce acid preparation into the skin and close pores?

• A. Positive pole; close pores; introduce acid into the skin.
• B. Negative pole; open pores; introduce alkaline.
• C. Positive pole; open pores; introduce alkaline.
• D. Negative pole; close pores; introduce acid.

Answer: (A)

The main idea is how iontophoresis moves charged particles into the skin using electricity. The ionized drug follows the electrical field: ions are driven out of the electrode that shares their charge and into the skin from the electrode with the same polarity as the drug’s charge. An acid preparation is positively charged, so it is pushed into the skin from the positive electrode (the anode). This delivers the acid directly into the skin and helps create a slightly acidic surface that can tighten pores.

That’s why using the positive pole to introduce acid into the skin and achieve pore tightening is the best fit. Using a negative pole would deliver negatively charged ions (alkaline) instead, which isn’t the goal here, and options that pair acid with a negative pole or describe opening pores don’t align with how iontophoresis drives charged substances and the expected effect on pores.