Simultaneous Determination of the Five Constituents in Maiwei Dihuang Pills by the HPLC-DAD Method

Objective. The purpose of study is to establish an HPLC-DAD method for determination of the five constituents (deoxyschizandrin, γ-schizandrin, loganin, paeoniflorin, and paeonol) in Maiwei Dihuang Pills. Methods. An Agilent ZORBAX SB-C18 chromatographic column was carried out to determine the five constituents of 50% methanol extract of Maiwei Dihuang Pills. Results. It was found the chromatographic peak resolution of each component in the study sample solution was 1.5 higher than that of other peaks and no peaks appeared in the blank control solution during the same time, suggesting specificity of HPLC-DAD was well established. The linearity test indicated that deoxyschizandrin, γ-schizandrin, loganin, paeoniflorin, and paeonol were 11.6–72.3 μg/mL, 6.4–45.2 μg/mL, 35.2–237.6 μg/mL, 18.1–114.2 μg/mL, and 32.2–215.3 μg/mL, respectively, suggesting each component has a good linear relationship within its own range. Additionally, the precision of HPLC-DAD was confirmed by a precision test; the stability of the study sample solution was confirmed by a stability test; and good reproducibility of HPLC-DAD was proved by a reproducible test. The recovery rate test showed that relative standard deviation (RSD) of recovery rate in deoxyschizandrin, γ-schizandrin, loganin, paeoniflorin, and paeonol was 100.26% (1.80%), 101.39% (1.74%), 101.19% (1.76%), 102.50% (1.65%), and 102.30% (1.58%), respectively. Conclusions. HPLC-DAD used to determine the five constituents in Maiwei Dihuang Pills, and it was easier and faster to operate, showing good condition in repeatability, precision, stability, and recovery, which is a great option for quality control.