ABSTRACT
A new method for chiral separation and purity inspection of landiolol hydrochloride and its stereoisomers was developed by ultra-performance convergence chromatography ( UPC2 ) . The mobile phase was the mixture of supercritical CO2 and methanol/n-butyl alcohol/acetonitrile (1:1:1, V/V) plus 0. 5%NH3?H2O. The separation was carried out on the Daicel CHIRALPAK? IF column (150 mm × 4. 6 mm, 3 μm) with a flow rate of 2. 8 mL/min at 50℃ using 223 nm as detection wavelength. Under the optimized experimental conditions, for R,R-stereoisomer, R,S-stereoisomer and S,R-stereoisomer, the detection limits (LOD, S/N=3) were 0. 3, 0. 4 and 0. 3 mg/L, the linear ranges were 2-300 mg/L, 5-300 mg/L and 2-300 mg/L, the recoveries of spike samples were 103. 4%±2. 5%, 91. 8%±2. 5% and 101. 7%±1. 5%, and the injection repeatabilities were 0. 06%, 0. 09% and 0. 08% (n=6), respectively. The experimental results demonstrate that the UPC2-based method can be used for the analysis and determination of landiolol hydrochloride and its stereoisomers.
ABSTRACT
The paper reports the systematic study on felodipine and its impurities in tablets, to improve its quality standards for the control of the related substances. HPLC-DAD, UPLC-MS, IR and NMR methods were used for the isolation of felodipine and its impurities in tablets, their identification and the zebrafish animal model was used for the analysis of the toxic impurities. In felodipine material and its tablets, three impurities are isolated and identified. They are impurity 1 [dimethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], impurity 2 [ethyl methyl 4-(2, 3-dichlorophenyl)-2, 6-dimethylpyridine-3, 5-dicarboxylate] and impurity 3 [diethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], separately. The result of zebrafish animal model analysis showed that the teratogenic effects of four compounds were: impurity 3 > or = felodipine > impurity 1 > impurity 2, lethal effects were as follows: impurity 2 = impurity 3 > felodipine > or = impurity 1. This study confirmed the toxicity of three impurities in felodipine. According to the results, the paper suggested the amendments to the standard of the medicine and provided the support to the control of impurities in the manufacturing process.