Composite affinity sorbents and their cleaning in place.

Area of Science:

• Biochemistry
• Chromatography
• Materials Science

Background:

• Reusable affinity sorbents are crucial for large-scale applications.
• Sterilization methods must be effective yet preserve immobilized ligand stability.
• Common agents like sodium hydroxide can degrade macromolecular ligands.

Purpose of the Study:

• To identify effective and non-damaging cleaning-in-place (CIP) solutions for affinity sorbents.
• To evaluate the efficacy of different chemical treatments for sorbent sterilization and pyrogen removal.
• To assess the impact of CIP treatments on the biochemical activity of immobilized ligands.

Main Methods:

• Tested various aqueous solutions, including sodium hydroxide, ethanol-acetic acid, and sodium hydroxide-ethanol mixtures, for sorbent sterilization.
• Assessed inactivation of *Bacillus subtilis* spores using single-step and sequential treatments.
• Evaluated pyrogen removal capabilities of the tested solutions.
• Investigated the stability of protein ligands on silica-based affinity sorbents after treatment.

Main Results:

• A mixture of sodium hydroxide and ethanol was effective for single-step sterilization.
• Neither sodium hydroxide nor ethanol-acetic acid alone completely inactivated *Bacillus subtilis* spores.
• Sequential application of hydroxide and ethanol-acetic acid treatments proved efficient.
• All tested solutions effectively removed pyrogens from chromatographic sorbents.
• Certain affinity silica sorbents with protein ligands tolerated the treatments without significant loss of biochemical activity.

Conclusions:

• A sodium hydroxide and ethanol mixture offers an effective one-step sterilization method for reusable affinity sorbents.
• The choice of an incompressible matrix is important for sorbent stability in ethanol-containing sterilizing solutions.
• Specific affinity sorbents demonstrate robustness, maintaining activity after exposure to validated cleaning and sterilization protocols.