Methods of making components for a medicinal delivery device are described, in which a base composition comprising a polysulphone is applied to the surface of a component to create a base layer, a primer composition comprising a silane having two or more reactive silane groups separated by an organic linker group is applied to the base layer to create primed surface, and a coating composition comprising an at least partially fluorinated compound is applied to the primed surface. Corresponding coated components and a medicinal delivery device are disclosed.