Objective: To prep 20(S)-PPD (protopanaxdiol) tablets

and establish the determination and in-vitro evaluation methods. Method: The determination method was established by HPLC

using C18 liquid chromatography column at a detecting wavelength of 203 nm

and acetonitrile-water (88∶12) as the mobile phase with flowing rate of 1.0 mL ·min-1. The dissolution behavior of 20(S)-PPD tablets was investigated by paddle method (second method listed in Volume II of Chinese Pharmacopeia)

in the 0.5% SDS solution at the rotating rate of 100 r ·min-1. The parameters of drug dissolution rate were treated with nonlinear regression by SAS software and iterated by Levenberg-Marquardt algorithm (LMA) to calculate Weibull’s distribution parameters and characteristic dissolution parameters. Result: The linear range of HPLC determination was 20.4-1 020.0 mg ·L-1(r=0.999 9)

with the average recovery rate 97.0% (RSD 1.99%). In the methodology study of dissolution

the tablets were completely dissolved in 20 min

with the linear range of 10.0-80.0 mg ·L-1(r=0.999 9)and the average recovery rate 99.9% (RSD 2.13%). In Weibull’s distribution analysis

the location parameter(α) was 0.526 6

the shape parameter(m) 0.602 1 and the scale parameter(β) 2.387 2. In characteristic dissolution profile

Td was 4.766 8 min and T50 2.834 7 min. Conclusion: The determination and in vitro evaluation methods is simple

exactly and reliable. SAS system is a convenient and rapid instrument to calculate Weibull’s distribution parameters and characteristic dissolution parameters.