Hydroxyapatite chromatography: purification strategies for recombinant proteins.

The purpose of this section is to provide developmental purification strategies for recombinant proteins on a column of hydroxyapatite and then to optimize them for repeated purification cycles using effect additives. Surface neutralization solutions (SNS) (patent pending) and/or the addition of calcium ions reduce the solubility of hydroxyapatite thus extending the column lifetime. This section leads the user through purification protocol screening followed by SNS--calcium ion supplementation step gradients for purifying a monoclonal antibody from its contaminants. The section provides simple analytical tools using a 160 ml scale column to predict column life at the process scale. However, the development engineer is encouraged to test the model in a minimum-sized process column.