Excipients: QUALITY ASSESSMENT OF POLYSORBATES 80 AND 20 PHARMACEUTICAL RAW MATERIALS BY MEASURING FATTY ACIDS COMPOSITION USING HPLC WITH MASS DETECTION

Importance of the Topic

Polysorbates 80 and 20 serve as essential non-ionic surfactants in pharmaceutical and food formulations. Ensuring their purity and composition is critical to the safety and efficacy of drug products. Traditional quality control methods based on GC-FID involve hydrolysis and derivatization of fatty acids, leading to extended sample preparation and analysis times. A faster, more direct approach using HPLC-MS can significantly improve throughput and reliability in routine excipient testing.

Objectives and Study Overview

The primary goal of this study was to develop and validate a simple, rapid HPLC-MS method for determining the fatty acid profiles of polysorbates 80 and 20 without complex sample pretreatment. The work compared reaction media for hydrolysis efficiency, optimized chromatographic and mass spectrometric conditions, and demonstrated compliance with USP monograph criteria across multiple batches.

Methodology and Instrumentation

Samples of polysorbates 80 and 20 were hydrolyzed with 1 M KOH at 40 °C for 6 hours to release free fatty acids. After neutralization with formic acid and dilution with water/ethanol, the solutions were directly injected into an HPLC system. Key instrumental parameters included:

• HPLC platform: ACQUITY Arc with isocratic solvent manager
• Column: XBridge BEH C18, 4.6 × 100 mm, 3.5 µm, 60 °C
• Mobile phase: 10 mM ammonium acetate in water (A) and acetonitrile (B)
• Flow rate: 2.0 mL/min; injection volume: 25 µL
• Mass detection: ACQUITY QDa single-quadrupole detector in negative electrospray mode
• Make-up solvent: 1 mM ammonium acetate in acetonitrile/water (50:50) for signal enhancement

Results and Discussion

The HPLC-MS method achieved baseline separation of USP-specified fatty acids and detected additional positional isomers. Screening of make-up solvents identified 1 mM ammonium acetate in acetonitrile/water as optimal, yielding the highest signal and lowest RSD. Unknown peaks in polysorbate 80 were identified by high-resolution QTof MS as conjugated linoleic isomers (Δ9,11; Δ10,12) and oleic isomers (cis-vaccenic and elaidic acids). Quantitative analysis via Single Ion Recording demonstrated that the fatty acid percentages in tested batches met USP acceptance criteria for both polysorbates 80 and 20.

Benefits and Practical Applications

• Eliminates derivatization and complex sample preparation, reducing analysis time.
• Direct detection of native fatty acids and isomers enhances method comprehensiveness.
• Integration with Empower software supports compliance and routine QC workflows.

Future Trends and Opportunities

Advances in high-resolution and tandem MS promise even greater specificity for excipient profiling. Automation of sample hydrolysis and direct infusion workflows could further increase throughput. Emerging regulatory expectations for excipient characterization will drive adoption of rapid, robust HPLC-MS techniques across the pharmaceutical industry.

Conclusion

The developed HPLC-MS method provides a fast, accurate, and compliance-ready solution for assessing the fatty acid composition of polysorbate 80 and 20 raw materials. By eliminating extensive sample pretreatment and expanding the detectable analyte range, this approach streamlines quality control and strengthens excipient characterization in pharmaceutical manufacturing.

References

• Martos A, Koch W, Jiskoot W, Wuchner K, Winter G, Friess W, Hawe A. Trends on Analytical Characterization of Polysorbates and Their Degradation Products in Biopharmaceutical Formulations. J Pharm Sci. 2017;106(6):1722–1735.
• Wang Z, Wang Y, Tie C, Zhang J. A Fast Strategy for Profiling and Identifying Pharmaceutical Excipient Polysorbates by UHPLC-HRMS. J Chromatogr A. 2021;1609:460450.
• United States Pharmacopeia. Monograph for Polysorbate 80, USP–NF 2021 Issue 1. Official Monograph, May 1 2020.
• United States Pharmacopeia. Monograph for Polysorbate 20, USP–NF 2021 Issue 1. Official Monograph, May 1 2020.
• Hu M, Niculescu M, Zhang XM, Hui A. High-Performance Liquid Chromatographic Determination of Polysorbate 80 in Pharmaceutical Suspensions. J Chromatogr A. 2003;984:233–236.