Qualitative Determination of Abietic Acid Improperly Used in Prepared Chinese Medicines

Importance of the Topic

Abietic acid is a resin acid widely used as a tackifier in adhesives and other industrial applications. Its presence in prepared Chinese medicines may indicate improper addition of resin materials and pose potential health risks. Qualitative detection ensures drug safety and compliance with regulatory standards.

Objectives and Study Overview

The study aimed to develop and validate a qualitative HPLC method with photodiode array detection using the Shimadzu Nexera series to identify abietic acid in five traditional Chinese medicine preparations. The method was designed based on supplementary testing methods (NMPA bulletins BJY 201908, BJY 201909, BJY 201919, BJY 202004, BJY 202005).

Used Instrumentation

• Shimadzu Nexera HPLC system (LC-40B XR pump, SIL-40C XR autosampler, CTO-40C column oven, DGU-405 degasser, SCL-40 controller, SPD-M40 PDA detector)
• Shim-pack VP-ODS column (150 mm × 4.6 mm I.D., 5 µm)
• LabSolutions chromatography software ver. 5.97

Methodology

Sample and control solutions were prepared in methanol or ethanol to yield 2–10 µg/mL abietic acid. Samples from Nujin pills, Jiebai capsules, Chenxiang Huazhi pills, Fengshi Ershiwuwei pills, and Shensanqi Shangyao capsules were extracted via sonication and filtration. Chromatographic conditions included 0.1% formic acid (A) and acetonitrile (B) at 1.0 mL/min, 40 ℃ column temperature, 241 nm detection wavelength, with isocratic or gradient elution tailored to each sample type.

Main Results and Discussion

No abietic acid peak was detected in any of the five sample chromatograms at the retention time of the control solution. Spiked samples confirmed peak identity by UV spectra matching with similarity indices above 0.98, except for a suspected interfering peak in Chenxiang Huazhi pills with a low similarity (0.6878). Theoretical plate counts exceeded regulatory requirements (≥2000 or ≥3000), demonstrating adequate chromatographic separation and method performance.

Benefits and Practical Applications

• High sensitivity and selectivity for qualitative detection of abietic acid
• UV spectral confirmation reduces false positives and improves specificity
• Compliance with national supplementary methods ensures regulatory acceptance
• Suitable for routine quality control in pharmaceutical and herbal medicine industries

Future Trends and Opportunities

Integration of mass spectrometric detection for quantitative analysis, automation of sample preparation, expansion to other resin acids, adoption of greener mobile phases, and application of chemometric and AI-driven spectral matching systems represent promising developments.

Conclusion

The developed HPLC–PDA method on the Shimadzu Nexera platform provides a robust qualitative assay for detecting improperly used abietic acid in traditional Chinese medicines. All tested products were free of abietic acid, confirming compliance with regulatory standards and demonstrating the method’s suitability for pharmaceutical quality assurance.

Reference

• NMPA supplementary testing methods BJY 201908, BJY 201909, BJY 201919, BJY 202004, BJY 202005