Method For Determination Of Enantiomers Research Articles

Enantioselective determination of a gastroprokinetic drug using amylose tris-(3,5-dimethylphenylcarbamate) as a stationary phase by HPLC

An enantioselective high-performance liquid chromatographic method for determination of enantiomers of mosapride citrate in bulk drugs and pharmaceuticals using UV–vis and polarimetric detectors in series has been developed. Baseline separation with resolution >2.0 was achieved on a column containing amylose tris-(3,5-dimethylphenylcarbamate) as stationary phase using a mobile phase consisting of n-hexane:ethanol:triethylamine (80:20:0.3, v/v/v) at 40 °C. The detection was carried out at UV-276 nm and enantiomers were identified by polarimetric detector. The effect of ethanol, 2-propanol, TEA, temperature and mobile phase flow rate on separation of MSP enantiomers was studied and the method was validated with respect to accuracy, precision, linearity and limits of detection and quantification. The linearity of the method was studied between 6.25 and 50 μg/ml and r 2 was >0.9997. The recoveries were in the range 99.63–100.22%, the method was suitable not only for process development of mosapride citrate but also for quality assurance of the individual enantiomers in bulk drugs and pharmaceuticals.

High-performance liquid chromatography separation and quantitation of ofloxacin enantiomers in rat microsomes

A sensitive, simple and accurate method for determination of enantiomers of ofloxacin in microsomal incubates was developed by chiral ligand-exchange RP-HPLC with fluorescence detection to examine stereoselective metabolism of ofloxacin in the glucuronidation process. The C 18 stationary phase was used as analytical column. The solution of chiral mobile phase additive was made up of 6 m M l-phenylalamine mixed with 3 m M CuSO 4 in water. Mobile phase consisted of the solution of chiral mobile phase additive–methanol (86:14).The fluorescence detector was operated at λ ex 330 nm and λ em 505 nm. The flow-rate of mobile phase was set at 1.0 ml/min. The achiral ODS column offers good separation of the two enantiomers in less than 25 min. The recovery of the assay was 97.9±6.1% ( n=10) for S-ofloxacin and 99.6±6.0% ( n=10) for R-ofloxacin. The method provides a high sensitivity and good precision (RSD<10%). The LOD was 0.6 μ M for both enantiomers and the LOQ was 5.70±0.45 μ M ( n=8) for S-ofloxacin and 5.66±0.47 μ M ( n=8) for R-ofloxacin. The standard curves showed excellent linearity over the concentration range 5.5–2078 μ M for S-(−)-ofloxacin and R-(+)-ofloxacin. The enantioselective method developed has been applied to determine the stereoselectivity of glucuronidation metabolism of ofloxacin optical isomers in rat liver microsomes.