Screening. In principle, all raw materials, of animal origine or produced by chemical synthesis, have to be rigourously tested and should fulfill certain quality attributes, when used for the production of biological injectables (GMP-guidelines). The characteristics which are frequently required to be described in raw materials are identity (testing, tracability, labels), purity (testing, inspection, vendor certificate of analysis), suitability for intended use (process validation, vendor audit programme, performance testing if needed), tracability (vendor audit programme, vendor certification, certificates of analysis, contractual obligations under change control, labelling, control). For more details, consult Lubiniecki and Shadle (1997) .