Analysis of Traditional Chinese Medicine Formula Granules for Quality Control

Significance of Topic

Traditional Chinese medicine (TCM) formula granules require reliable quality control through characteristic chromatograms defined by national standards. High‐performance liquid chromatography (HPLC) is the preferred technique, but variations in column selectivity and backpressure can challenge method reproducibility across laboratories. Evaluating alternative columns that meet system suitability criteria without extensive method adjustment is crucial for pharmaceutical QC.

Objectives and Study Overview

This study aimed to reproduce a standard HPLC method for a TCM formula granule derived from Desmodium styracifolium using an Agilent InfinityLab Poroshell 120 Aq-C18 column. The goal was to verify that this superficially porous 2.7 µm column meets all system suitability requirements and offers comparable performance to the original sub-2 µm column under unchanged chromatographic conditions.

Methodology and Instrumentation

• Instrumentation: Agilent 1290 Infinity II LC system with quaternary pump, flexible pump (G7104A), multisampler (G7167B), multicolumn thermostat (G7116B), and diode array detector (G7117B).
• Column: Agilent InfinityLab Poroshell 120 Aq-C18, 2.1 × 150 mm, 2.7 µm.
• Mobile phase: A) 0.1 % phosphoric acid in water; B) acetonitrile; gradient from 15 % B (0–10 min) to 16 % B (11–20 min); post-run 5 min.
• Flow rate: 1.5 mL/min; column temperature: 30 °C; injection volume: 1 µL; detection at UV 340 nm, 20 Hz.
• Sample preparation: granule dissolved in 80 % methanol per national standard.

Main Results and Discussion

The Poroshell 120 column produced chromatograms closely matching those on the vendor’s original 1.6 µm column, with half the backpressure (≈207 bar vs 452 bar). System suitability metrics met or exceeded requirements: relative retention times for seven characteristic peaks were within ±10 % of standards, and theoretical plates for peak 3 reached 21 659 (vs ≥ 10 000). Relative peak area for peak 6 was 0.56 (≥ 0.366). Adjusting flow from 0.20 to 0.22 mL/min preserved retention times, demonstrating method robustness.

Benefits and Practical Applications

• Reduced backpressure extends column lifetime and lowers maintenance in high-throughput labs.
• Superficially porous particles yield efficiency comparable to sub-2 µm phases with simpler sample preparation and less risk of clogging.
• Strong retention of polar analytes enhances detection of key TCM constituents.
• Direct compatibility with existing protocols minimizes need for revalidation when replacing columns.

Future Trends and Applications

Developments may include accelerated gradient methods, further reduction in analysis time, and coupling with mass spectrometry for enhanced compound identification. AI-driven method optimization could streamline column selection for diverse TCM formulas. Expanding the use of superficially porous columns in multi-analyte QC and process analytics will improve throughput and data consistency.

Conclusion

The Agilent InfinityLab Poroshell 120 Aq-C18 column successfully replicates a standard HPLC method for Desmodium styracifolium TCM granules, meeting all system suitability requirements with lower backpressure and high efficiency. It offers a practical, robust alternative for pharmaceutical quality control without altering established parameters.

References

• China State Food and Drug Administration. National Drug Standard YBZ-PFKL-2021054.
• Fu, R.-J.; Wei, T.-C. Analysis of Polar Compounds Using an Agilent InfinityLab Poroshell 120 Aq-C18 Column with Improved and Reliable Performance, Agilent Technologies Application Note 5994-5555EN, 2022.