Aim To establish a HPLC method for the separation of the enantiomers of zolmitriptan. Methods The separations were performed on Chiralcel OJ column with hexane-ethanol-diethylamine（85：15：0.2） as mobile phase at a ...Aim To establish a HPLC method for the separation of the enantiomers of zolmitriptan. Methods The separations were performed on Chiralcel OJ column with hexane-ethanol-diethylamine（85：15：0.2） as mobile phase at a flow rate of 0.8 mL·min^-1 and detecttion wavelength of 227 nm at 35 ℃. Several related parameters for separation were studied. Results Baseline separation （Rs 〉 1.5） was easily obtained in the case, and the R-isomer impurity in zolmitriptan was determined. Conclusion The method developed in this study has been successfully applied for quality-control purposes.展开更多
Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb...Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k') and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.展开更多
We developed a chiral HPLC method for the separation and analysis ofnaftopidil enantiomers. The two enantiomers of naflopidil were separated using a Chiralpak AD-H （250 mm×4.6 mm, 5 μm） column and monitored at...We developed a chiral HPLC method for the separation and analysis ofnaftopidil enantiomers. The two enantiomers of naflopidil were separated using a Chiralpak AD-H （250 mm×4.6 mm, 5 μm） column and monitored at the wavelength of 283 nm. The isocratic mobile phase consisting of hexane-isopropanol-diethylamine （85：15：0.1, v/v/v） was pumped at a flow rate of 1.0 mL/min. Under these chromatographic conditions, R-naflopidil and S-naftopidil were well separated and had good linearity in the ranges of 0.78-50 μg/mL （r = 0.9999） and 0.84-54 μg/mL （r = 0.9998）, respectively. The relative standard deviations （RSD） of intra- and inter-day assays were no more than 0.5% and 0.7%, respectively. This improved method for the separation and quantitative determination of naflopidil enantiomers can be used for the quality control of synthesized naflopidil product.展开更多
文摘Aim To establish a HPLC method for the separation of the enantiomers of zolmitriptan. Methods The separations were performed on Chiralcel OJ column with hexane-ethanol-diethylamine（85：15：0.2） as mobile phase at a flow rate of 0.8 mL·min^-1 and detecttion wavelength of 227 nm at 35 ℃. Several related parameters for separation were studied. Results Baseline separation （Rs 〉 1.5） was easily obtained in the case, and the R-isomer impurity in zolmitriptan was determined. Conclusion The method developed in this study has been successfully applied for quality-control purposes.
基金Supported by China Postdoctoral Science Fund (20090461007)Postdoctoral Research Funding Special Plans of Hunan(2010RC4025)Graduate Innovation Research Project of Hunan (CX2010B295)
文摘Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k') and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.
基金Guangzhou Science and Technology Projects of Apecial Areas of Innovative Medicines (Grant No.2006Z2-E4011)2006 Guangdong Province Technology Projects (Grant No. 2006B35501003)
文摘We developed a chiral HPLC method for the separation and analysis ofnaftopidil enantiomers. The two enantiomers of naflopidil were separated using a Chiralpak AD-H （250 mm×4.6 mm, 5 μm） column and monitored at the wavelength of 283 nm. The isocratic mobile phase consisting of hexane-isopropanol-diethylamine （85：15：0.1, v/v/v） was pumped at a flow rate of 1.0 mL/min. Under these chromatographic conditions, R-naflopidil and S-naftopidil were well separated and had good linearity in the ranges of 0.78-50 μg/mL （r = 0.9999） and 0.84-54 μg/mL （r = 0.9998）, respectively. The relative standard deviations （RSD） of intra- and inter-day assays were no more than 0.5% and 0.7%, respectively. This improved method for the separation and quantitative determination of naflopidil enantiomers can be used for the quality control of synthesized naflopidil product.
