Chiral liquid chromatography resolution and stereoselective pharmacokinetic study of indapamide enantiomers in rats

This investigation describes a precise and accurate stereoselective HPLC method for the simultaneous determination of indapamide enantiomers in whole blood to follow its pharmacokinetics in rats up to 24 h after single oral dosing. Enantiomeric resolution was achieved on a cellulose tris (3,5-dichlorophenylcarbamate) column known as Chiralpak IC, with UV detection at 240 nm, and the mobile phase consisted of n-hexane and isopropanol (70:30, v/v). Using the chromatographic conditions described, indapamide enantiomers were well resolved with a resolution factor (Rs) of at least 2.0 and with retention times of 19.2 and 23.3 min, respectively. Linear responses (r > 0.999) were observed over the range of 0.05–50 μg/mL of indapamide enantiomers, with quantitation limit of 0.05 μg/mL. The mean relative standard deviation (RSD) of within-day precision and accuracy of the drug were <10%. The mean extraction efficiency was greater than 86% for each enantiomer. The assay method shows good specificity to indapamide enantiomers, and it could be successfully applied to its pharmacokinetic studies and to therapeutic drug monitoring.