Simultaneous chemical fingerprint and quantitative analysis of saponins in Gongxuening capsule by HPLC-CAD

Abstract Background Gongxuening capsule (GXN) is a commonly used Chinese patent medicine for treating gynecological diseases in China. Currently, the available detection methods are constrained and inadequate due to the complex chemical composition of the capsule. The saponin components have a wide range of polarities and a weak response in low-band ultraviolet detection, which is compounded by numerous interference peaks. These factors make it difficult to accurately quantify the active ingredients. Objective This study aims to develop the chromatographic fingerprint of GXN using high-performance liquid chromatography in conjunction with a charged aerosol detector (HPLC-CAD) and quantitatively analyze its principal components. Methods A chromatographic separation was performed on an Acclaim C30 column (3 mm × 250 mm, 3 µm) with a gradient elution program using a mixture of acetonitrile (A) and water (B) as mobile phase: (0–5 min, 40% A; 5–20 min, 40–45% A; 20–35 min, 45–50% A; 35–45 min, 50% A). The flow rate was maintained at 0.4 mL min −1 , and the column temperature was set at 10 °C. An injection volume of 1 μL was used, and the sampling frequency was 5 Hz, with a filtration constant of 3.6 s, and an atomization temperature of 50 °C. Six batches of GXN were subjected to chromatographic fingerprinting to establish their similarity. Furthermore, the quantification of the principal components was conducted to determine their content. Results The HPLC chromatographic fingerprint of GXN was established, and 9 common peaks were identified with 6 batches of samples sharing a close similarity, which is greater than 0.960. Polyphyllin I (PPI), polyphyllin II (PPII), polyphyllin VII (PPVII), polyphyllin D (PPD), polyphyllin H (PPH) and gracillin had a good linearity with peak area within the corresponding concentration range. Correlation coefficients were >0.999, and the recovery of the method was in the range of 98.56–101.50%, with RSD values below 2.0%. Conclusion The developed method demonstrated broad applicability, high sensitivity, excellent repeatability, and strong reliability, making it suitable for detecting and controlling the quality of complex Rhizoma Paridis Saponins (RPS) in GXN.