Development and validation of simultaneous HPLC-PDA analysis method for quality control of Hwang-ryeon-hae-dok-tang: An analytical quality by design approach

This study introduces an advanced analytical method for quality control of botanical drugs, focusing on Hwang-ryeon-hae-dok-tang (HRHDT), a traditional herbal prescription utilized for inflammation, gastritis, fever, and hypertension. Botanical drugs pose a challenge due to their complex composition, requiring reliable and robust analytical techniques. Our step-by-step procedure included defining the analytical target profile, risk assessment, screening and optimizing design of experiment, measuring the design space, and Monte Carlo simulation. The established HPLC-PDA method enables the simultaneous analysis of four major compounds (geniposide, baicalin, palmatine, and berberine) present in HRHDT. The optimized conditions involve a gradient elution with acetonitrile and water, both containing 0.1% trifluoroacetic acid, a 32 °C column temperature, 254 nm detection wavelength, and 1.0 mL/min flow rate. A successful validation demonstrated excellent linearity (R²: 0.9984–0.9989) and accuracy (recovery: 100.61%–102.44%), with precise repeatability and intermediate precision (%RSD: 0.39%–0.83%). These results further confirm the reliability and accuracy of the analytical method. Overall, our design-based approach not only facilitated the development of robust analytical methods but also allowed for flexible operation ranges. Therefore, this methodology holds significant potential for ensuring the quality of botanical drug products within the pharmaceutical industry.