Visible and Sub-visible Particle Formation for a Model Bioconjugate

Area of Science:

• Biopharmaceutical formulation
• Protein aggregation
• Particle characterization

Background:

• Protein-based therapeutics are susceptible to aggregation and particle formation.
• Interfacial stress during manufacturing and storage can induce these changes.
• Understanding particle formation mechanisms is crucial for drug stability.

Purpose of the Study:

• To investigate the relationship between interfacial area (IA) and particle formation (visible particles [VP] and sub-visible particles [SVP]).
• To characterize the time-course and morphology of particle formation in a model bioconjugate under varying interfacial conditions.

Main Methods:

• A model bioconjugate was agitated in glass vials at different angles (0° to 90°) to vary the air-water interfacial area (IA) up to 478 mm².
• Visible and sub-visible particle formation was monitored over time.
• Protein concentration and soluble aggregates were assessed.

Main Results:

• Particle formation (VP and SVP) significantly increased with increasing air-water IA.
• A threshold IA of approximately 305 mm² was identified, above which substantial particle formation occurred.
• Sub-visible particles initially increased then depleted, suggesting conversion to visible particles; protein concentration decreased with extended agitation.

Conclusions:

• Interfacial area is a critical factor driving both visible and sub-visible particle formation in this model bioconjugate.
• A dynamic interplay exists between sub-visible and visible particle populations.
• Manufacturing processes should control interfacial area to mitigate biopharmaceutical particle formation and ensure protein stability.