RESUMO
A simple and sensitive HPLC method was developed for simultaneous determination of danshensu (DSS), rosmarinic acid (RA), lithospermic acid (LA), salvianolic acid B (SAB), and hyperoside (HP) in rat plasma. This method validated was successfully applied to the pharmacokinetic study of the main active ingredients after oral administration of Radix Salviae Miltiorrhizae extract (SME), hawthorn extract (HTE), and a combination of both extracts (2.5 : 1) to rats. The results indicated that there have been great differences in pharmacokinetics between a single extract and a combination of both extracts. A combination of both extracts can enhance their bioavailabilities and delay the elimination of SAB and DSS in rats.
RESUMO
The present paper introduced the principle of clustering of variables around latent components method, and used this method in selecting spectrum range of the NIR quantitative analysis models. Taking tobacco samples as experiment materials, we dealed with 107 sample spectra, divided the spectra into 5 clusters, and explained the information reflected by each of these 5 clusters in terms of chemistry. On this basis, we chose the corresponding wavelength range to set up the quantitative models of the total sugar, reducing sugar and nicotine by PLS method. Compared with the model based on the full NIR spectral range, Rtraining of the models based on the chosen spectral range rose from 0.977 1, 0.917 2 and 0.987 4 to 0.995 5, 0.975 1 and 0.994 4; Rtest rose from 0.977 8, 0.941 2 and 0.993 2 to 0.992 7, 0.967 9 and 0.994 0; RMSECV dropped from 1.09, 1.43, 0.14 to 1.05, 1.05 and 0.13, RMSEP dropped from 0.92, 1.17 and 0.16 to 0.39, 0.63 and 0.11 and the D value dropped from 1.274%, 1.972% and 0.829% to 0.711%, 0.843% and 0.768% for the total sugar, reducing sugar and nicotine, respectively. These data indicated that this method can improve the forecasting precision and stability of the model, so offers certain guidance on practical application.
