Qualitative and Quantitative Study of Tibetan Medicine Thlaspi semen / 中国药房

OBJECTIVE： To establish the qualitative and quantitative control method of Tibetan medicine Thlaspi semen. METHODS： TLC and HPLC method were used to identify and determine flavonoids isovitexin， swertisin and glucosinolates sinigrin from 15 batches of T. semen. The stationary phases identified by TLC of flavonoids and glucosinolates were polyamide film and high performance silica gel GF254. The developing agents were trichloromethane-methanol-glacial acetic acid （11 ∶ 1 ∶ 1，V/V/V） and ethyl acetate-methanol- triethylamine （4 ∶ 5 ∶ 0.5，V/V/V）. In chromatogram condition of content determination of isovitexin and swertisin， the separation was performed on CAPCELL PAK MGⅡ C18 column with mobile phase composed of acetonitrile-0.4％ glacial acetic acid solution （gradient elution） at the flow rate of 1.0 mL/min. The detection wavelength was set at 336 nm. In chromatogram condition of content determination of sinigrin， the separation was performed on CAPCELL PAK MGⅡ C18 column with mobile phase composed of acetonitrile-0.02 mol/L tetrabutylammonium hydrogen sulfate （15 ∶ 85，V/V，pH 6） at the flow rate of 1.0 mL/min. The detection wavelength was set at 227 nm. RESULTS： In TLC identification chromatogram， spots corresponding to isovitexin， swertisin and sinigrin control were detected in test samples. The linear ranges of isovitexin， swertisin and sinigrin were 1.26-79.00， 1.21-75.38， 12.80-640.00 μg/mL， respectively （all r≥0.999 5）. The limits of detection （LODs） were 0.09， 0.12， 0.15 μg/mL， and limits of quantitation （LOQs） were 0.39， 0.43， 0.54 μg/mL， respectively. RSDs of precision， stability （24 h） and reproducibility tests were all lower than 2.0％（n＝6）. The recoveries were 99.1％， 97.0％ and 98.1％， and RSDs were 1.9％， 1.8％， 1.8％（n＝6），respectively. The contents of isovitexin， swertisin and sinigrin in 15 batches of T. semen were 0.013-0.090， 0.020-0.130 and 18.92-40.75 mg/g， respectively. CONCLUSIONS： Established quality control method is simple， reproducible and stable， and can be used for the quality control of Tibetan medicine T. semen.

Forced degradation of gliquidone and development of validated stability-indicating HPLC and TLC methods

Forced degradation studies of gliquidone were conducted under different stress conditions. Three degradates were observed upon using HPLC and TLC and elucidated by LC-MS and IR. HPLC method was performed on C18 column using methanol-water (85:15 v/v) pH 3.5 as a mobile phase with isocratic mode at 1 mL.min-1 and detection at 225 nm. HPLC analysis was applied in range of 0.5-20 µg.mL-1 (r =1) with limit of detection (LOD) 0.177 µg.mL-1. TLC method was based on the separation of gliquidone from degradation products on silica gel TLC F254 plates using chloroform-cyclohexane-glacial acetic acid (6:3:1v/v) as a developing system with relative retardation 1.15±0.01. Densitometric measurements were achieved in range of 2 -20 µg /band at 254 nm (r = 0.9999) with LOD of 0.26 µg /band. Least squares regression analysis was applied to provide mathematical estimates of the degree of linearity. The analysis revealed a linear calibration for HPLC where a binomial relationship for TLC. Stability testing and methods validation have been evaluated according to International Conference on Harmonization guidelines. Moreover, the proposed methods were applied for the analysis of tablets and the results obtained were statistically compared with those of pharmacopeial method revealing no significant difference about accuracy and precision.