Which route uses a patch to deliver drugs into the systemic circulation?

Which route uses a patch to deliver drugs into the systemic circulation?

• A. Nasal route
• B. Ocular route
• C. Topical route
• D. Transdermal route

Answer: (D)

Transdermal delivery uses a patch to move drug from the skin into the systemic circulation. The patch places the drug in a reservoir or adhesive layer on the skin, and the medication diffuses through the stratum corneum and into dermal capillaries, producing systemic effects. This route bypasses first-pass metabolism in the liver, allowing more stable, prolonged plasma levels with convenient dosing intervals. Drugs chosen for transdermal delivery tend to be potent, with low molecular weight and suitable lipophilicity, so they can cross the skin barrier efficiently (examples include certain narcotics, nicotine, and hormone therapies). The nasal, ocular, and topical routes are typically used for local effects or non-patch systemic delivery, but they do not employ a patch to achieve systemic exposure.

Transdermal delivery uses a patch to move drug from the skin into the systemic circulation. The patch places the drug in a reservoir or adhesive layer on the skin, and the medication diffuses through the stratum corneum and into dermal capillaries, producing systemic effects. This route bypasses first-pass metabolism in the liver, allowing more stable, prolonged plasma levels with convenient dosing intervals. Drugs chosen for transdermal delivery tend to be potent, with low molecular weight and suitable lipophilicity, so they can cross the skin barrier efficiently (examples include certain narcotics, nicotine, and hormone therapies). The nasal, ocular, and topical routes are typically used for local effects or non-patch systemic delivery, but they do not employ a patch to achieve systemic exposure.