Determination of the lipophilicity of Salvia miltiorrhiza Radix et Rhizoma (danshen root) ingredients by microemulsion liquid chromatography: optimization using cluster analysis and a linear solvation energy relationship-based method.

We evaluated 26 microemulsion liquid chromatography (MELC) systems for their potential as high-throughput screening platforms capable of modeling the partitioning behaviors of drug compounds in an n-octanol-water system, and for predicting the lipophilicity of those compounds (i.e. logP values). The MELC systems were compared by cluster analysis and a linear solvation energy relationship (LSER)-based method, and the optimal system was identified by comparing their Euclidean distances with the LSER coefficients. The most effective MELC system had a mobile phase consisting of 6.0% (w/w) Brij35 (a detergent), 6.6% (w/w) butanol, 0.8% (w/w) cyclohexane, 86.6% (w/w) buffer solution and 8 mm cetyltrimethyl ammonium bromide. The reliability of the established platform was confirmed by the agreement between the experimental data and the predicted values. The logP values of the ingredients of danshen root (Salvia miltiorrhiza Radix et Rhizoma) were then predicted. Copyright © 2015 John Wiley & Sons, Ltd.

Optimization of liquid chromatographic method for the separation of nine hydrophilic and hydrophobic components in Salviae miltiorrhizae Radix et Rhizoma (Danshen) using microemulsion as eluent.

In this study, we have proposed and developed a novel, environmental-friendly and simple method for separation of nine hydrophilic and hydrophobic components in Danshen using microemulsion liquid chromatography. The proposed method was optimized via the preliminary screening experiment and the experimental design. The following factors were investigated in preliminary screening experiment: pH of mobile phase, column type, the nature of surfactant, the nature of oil phase and additives. In order to simultaneously optimize resolution and analysis time, the chromatographic optimization function (COF) was adopted to evaluate chromatograms. The central composite design (CCD) was used to create the matrix of experiments for mapping the chromatographic response surface. Finally, the COF values were fitted into a second order polynomial model and the response surface methodology (RSM) was employed to find the optimal eluent constituents. The reliability of the established model was confirmed by the good agreement obtained between experimental data and predictive values. Based on the results from the preliminary screening experiment and the CCD optimization, the optimal mobile phase was identified as a solution consisting of 6.68% (w/w) polyoxyethylene lauryl ether (Brij35), 0.84% (w/w) cyclohexane, 6.92% (w/w) n-butanol, 85.56% (w/w) phosphate buffer (pH 6.60) and 8mM cetyltrimethyl ammonium bromide (CTAB).

[Simultaneous determination of four fat-soluble vitamins by microemulsion liquid chromatography].

A novel system was developed for the rapid determination of fat-soluble vitamins A, D2, D3 and E with microemulsion liquid chromatography (MELC). The effects of operating parameters on the separation selectivity were investigated. The optimized microemulsion system consisted of 98% (v/v) of 50 g/L sodium dodecyl sulfate (SDS)-10% (w/w) n-butanol-1.0% (w/w) n-octane-84% water (w/w) and 2% (v/v) acetonitrile. The type and content of surfactant, the content of oil phase and the organic additive (acetonitrile) were found to play important roles in the separation of four fat-soluble vitamins. The four analytes were baseline separated within 20 min on a Venusil ASB C18 column (150 mm x4.6 mm, 5 microm) with a flow rate of 0. 7 mL/min and the detection wavelength of 265 nm at 40 degrees C. The relative standard derivations (RSDs, n = 5) of retention times and peak areas of the analytes were less than 2. 3% and 3. 0%, respectively. The linear ranges of vitamins A, D2, D3 and E were 22.0 - 88.0 mg/L, 20.2 - 81. 0 mg/L, 24.3 -97.2 mg/L and 125.0 -500.0 mg/L, with their correlation coefficients ( r2 ) of 0. 999 6, 0. 999 4, 0. 999 8 and 0. 999 8, respectively. The detection limits (S/N = 3) were 0. 37, 0.34, 0.41 and 2. 12 mg/L, respectively. This method was successfully applied to the determination of commercial Vitamins with Minerals Tablets (21), and the results were satisfactory.