A permeable composition, a controlled release product, and methods for producing the permeable composition and controlled release product. The permeable composition includes a matrix material, a particulate filler material, and interfacial passageways between the matrix material and the particles of filler material. The matrix material may include a substrate material and a carrier material. The controlled release product is formed by coating a substrate material with at least one layer of the permeable composition. The methods include the steps of applying a degradable surface treatment material to the particles of filler material and then dispersing the surface treated filler material throughout the matrix material so that degradable interfaces are provided between the matrix material and the particles of filler material.