How are intradermal drugs delivered?

Intradermal drugs are delivered using a method that involves injection directly into the dermis, which is the layer of skin just beneath the epidermis. This method targets the skin's immune response while providing a localized effect of the medication. This route is often used for allergy testing and vaccinations, as it allows for a rapid immune response to be elicited.

The other options describe different delivery methods that do not accurately reflect the mechanism of intradermal drug delivery. Oral administration involves ingesting medication, which is absorbed through the digestive system, while transdermal patches deliver drugs through the skin over a longer period. Inhalation involves the intake of substances in a gaseous form, typically for respiratory conditions. Each of these delivery methods has its unique pharmacokinetics and applications and does not fit the definition or purpose of intradermal delivery.