Catapres® patch is an example of which transdermal patch type?

• A. Reservoir-type
• B. Matrix-type
• C. Adhesive-type
• D. None

Answer: (B)

The question is about how transdermal patches control drug release. Catapres delivers clonidine through a matrix-type system, where the drug is dispersed throughout a polymer matrix that also acts as the adhesive to the skin. The release of clonidine is driven by diffusion out of this matrix, providing a steady, controlled flow to the skin.

This differs from a reservoir-type patch, which would keep the drug in a separate reservoir separated from the skin by a rate-controlling membrane, and from a purely adhesive-type patch, where the drug is in the adhesive layer itself without a distinct matrix controlling release. The Catapres patch fits the matrix-type design because the active drug is embedded in the matrix that governs how it diffuses to the skin.