an article for the controlled delivery of an active substance , comprising a hollow space fully enclosed by a wall and filled in full or in part with one or more active substances , which wall is made using a biodegradable polymeric material permeable to the active substance , wherein the wall is composed mainly of a combination of at least two different polymeric materials in which one polymeric material is permeable to the active substance and is degradable and the other polymeric material is relatively poorly permeable to the active substance and is degradable and the conveyor path for the delivery of the active substance from the hollow space to the surroundings of the article is a continuous distance leading at least through the polymeric material permeable to the active substance .