Which statement best describes a matrix-type patch?

Which statement best describes a matrix-type patch?

• A. The drug is evenly distributed through an adhesive matrix.
• B. The drug is contained in a reservoir between layers.
• C. The patch is designed to be easily cut without affecting dose.
• D. The patch uses a rate-controlling membrane.

Answer: (A)

Matrix-type patches place the drug evenly distributed within an adhesive polymer matrix, which is the layer that sticks to the skin. The drug then diffuses out of this matrix into the skin, so the release is governed by diffusion through that adhesive matrix. This description directly captures the defining feature of a matrix-type patch. In contrast, patches that have the drug in a separate reservoir between layers rely on a rate-controlling membrane to regulate release, and statements about cutting the patch or about a rate-controlling membrane point to other designs rather than the matrix type.

Matrix-type patches place the drug evenly distributed within an adhesive polymer matrix, which is the layer that sticks to the skin. The drug then diffuses out of this matrix into the skin, so the release is governed by diffusion through that adhesive matrix. This description directly captures the defining feature of a matrix-type patch. In contrast, patches that have the drug in a separate reservoir between layers rely on a rate-controlling membrane to regulate release, and statements about cutting the patch or about a rate-controlling membrane point to other designs rather than the matrix type.