Application of hanging drop technique to optimize human IgG formulations

Area of Science:

• Biochemistry
• Pharmaceutical Sciences
• Protein Chemistry

Background:

• Human immunoglobulin G (IgG) is a crucial therapeutic protein requiring stable formulations.
• Early-stage screening of excipients is vital for developing effective IgG formulations.
• The hanging drop technique offers a potential method for rapid formulation assessment.

Purpose of the Study:

• To evaluate the efficacy of the hanging drop technique for screening excipients in human IgG formulation development.
• To identify optimal formulation conditions, including pH, salt concentration, and excipients, for IgG stability and solubility.

Main Methods:

• Utilized a stereomicroscope to monitor IgG microdrops undergoing vapor diffusion via the hanging drop technique.
• Prepared and characterized aqueous IgG solutions with varying pH, salt concentrations, and excipients.
• Employed dynamic light scattering, differential scanning calorimetry, and size exclusion chromatography for validation.

Main Results:

• Low concentrations of sodium/potassium phosphate or McIlvaine buffer enhanced IgG solubility.
• Sucrose addition promoted IgG stability, whereas NaCl addition increased aggregation.
• Antimicrobial preservatives exhibited complex effects dependent on buffer conditions.

Conclusions:

• The hanging drop technique is a simple and efficient method for early-stage screening of protein formulations.
• This technique facilitates the identification of excipients and conditions that promote IgG solubility and stability.
• Results support the use of hanging drop for rapid assessment in biopharmaceutical development.