The invention relates to an article with an improved buffer layer architecture comprising a substrate having a metal surface, and an epitaxial buffer layer on the surface of the substrate. Shark cartilage extracts having anti-angiogenic, anti-tumor, anti-inflammatory and anti-collagenolytic activities have been obtained by an improved process. The flowpath diverges from centreline in a downstream direction thereof and has a cross-section area in a direction perpendicular to the centreline that remains substantially equal or decreases in the downstream direction of the flowpath.