Association Constant - A reaction between antibody and its determinant which comprises a measure of affinity. Immunoassay - A qualitative or quantitative assay method based on the measure of interplay of excessive affinity antibody with antigen used to identify and quantify proteins. High Performance Liquid Chromatography (HPLC) - An instrumental separation method used to characterize or to find out the purity of a BDP by passing the product (or its part peptides or website amino acids) in liquid kind over a chromatographic column containing a stable help matrix.