SNS: An Effective Strategy for Extending Ceramic Hydroxyapatite Column Life
DENG Yi-xi;LI Ji-dong;LI Le;MENG Guo-ji;YU Yu-gen;Shenzhen Main Luck Pharmaceuticals Inc.;Bio-Rad Laboratories ( Shanghai) Ltd.;
Ceramic Hydroxyapatite( CHT) has been widely used in the manufacturing of a wide variety of monoclonal antibodies( m Abs),vaccines,and other protein therapeutics. It is an effective tool for the removal of residual host cell proteins, nucleic acids, viruses, endotoxins, and product-related contaminants such as aggregates and degradation fragments. However,damage of the CHT media and increased column back pressure are often observed at production scale-up. A transient p H excursion during elution with increased salt concentration leads to Ca~(2 +)depletion from the CHT column. In the present study,the effect of surface neutralization system( SNS) on the life cycles of CHT media is demonstrated. Following post-loading wash,a buffer with slightly elevated p H is applied onto the column so as to prevent significant p H drop during target protein elution. The level of Ca~(2 +)depletion in response to p H and salt concentration of the SNS buffer have been investigated,and the optimal buffer composition for maintaining the p H of column effluent near neutral been identified. This newly developed protocol has been validated for the polish purification of m Ab WLB304. The dynamic binding capacity of WLB304,impurity clearance efficiency,leached Ca~(2 +)level,p H excursion and column back pressure during purification process were closely monitored. Data indicate that the implementation of SNS can significantly reduce Ca~(2 +)depletion and effectively extend the life time of a CHT column,without compromising its chromatography performance.