NMR method for accurate quantification of polysorbate 80 copolymer composition

Area of Science:

• Analytical Chemistry
• Polymer Chemistry

Background:

• Polysorbate 80 is a widely used non-ionic surfactant with a complex composition.
• Accurate characterization of polysorbate 80 is essential for its applications and safety.
• Existing analytical methods may not fully resolve the intricate mixture of polysorbate 80 components.

Purpose of the Study:

• To evaluate Carbon-13 Nuclear Magnetic Resonance (13C NMR) spectroscopy as a quantitative tool for analyzing polysorbate 80.
• To characterize the oligomeric composition of commercial polysorbate 80 formulations.
• To correlate polysorbate 80 composition with potential biological implications.

Main Methods:

• Quantitative (13)C NMR spectroscopy was employed using short relaxation delays and a 30° pulse width.
• Analysis focused on identifying and quantifying sorbitan polyethoxylate esters, isosorbide polyethoxylate esters, and poly(ethylene glycol) (PEG) esters.
• The degree of polymerization and end-group ratios of poly(ethylene glycol) chains were determined.

Main Results:

• Commercial polysorbate 80 is a complex oligomeric mixture, with PEG esters identified as the major component.
• The ratios of major oligomers were successfully quantified.
• Analysis revealed potential inconsistencies in raw material feed ratios and reaction conditions during polysorbate 80 production.
• Hydrophilic/hydrophobic balance, indicated by PEG chain characteristics, was analyzed.

Conclusions:

• (13)C NMR spectroscopy is a powerful and universal tool for the quantitative analysis of polysorbate 80.
• The findings highlight the need for better control over polysorbate 80 production processes.
• Accurate compositional analysis is critical for synthesizing high-quality polysorbate 80, offering insights into potential adverse biological reactions.