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 24h after single oral dosing. Enantiomeric resolution was achieved on a cellulose tris (3,5-dichlorophenylcarbamate) column known as Chiralpak IC, with UV detection at 240nm, 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 23.3min, respectively. Linear responses (r>0.999) were observed over the range of 0.05-50μg/mL of indapamide enantiomers, with quantitation limit of 0.05μg/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.