Optimizing Manufacturing Based on the Storage Stability of Pegylated Products

Abstract

PEG conjugation was carried out through integration of a carbamate (urethane) linkage, between N-atoms of the imidazole side-chain of His34 or the p-NH2 group of N-terminal Cysteine residue, or the C-NH2 group of Lysine side-chains of interferon alfa-2b and a 12-kDa mPEG-SC molecule. Secondary structure analysis of the test samples of peginterferon alfa-2b exposed to repeated freezing and thawing was conducted by CD spectroscopy in the far-UV (260-190 nm) region to assess the effect on structural integrity of protein. [...]storage conditions during various manufacturing process steps must be selected very carefully, based on the pegylation chemistry utilized, the type of protein molecule involved (i.e., single subunit vs. multiple subunits) and degree of pegylation. Another pegylated product, Pegasys (peginterferon alfa-2a) which is prepared by conjugating interferon alfa-2a with an NHS-activated, 40-kDa branched PEG molecule with stable amide linkage supplied as a liquid solution with the shelf-life of two years when stored between +2 °C and +8 °C whereas Oncaspar has a shelf-life of only eight months, due to removal of PEG from its protein backbone.