A Validated Chiral LC Method for the Enantiomeric Separation of Nateglinide and the Quantitative Determination of Its L-Enantiomer

A simple and accurate chiral liquid chromatographic method was developed for the enantiomeric purity determination of D-nateglinide and quantitative determination of L-nateglinide in bulk drug samples. Good resolution (R-s > 6.0) between D-enantiomer and L-enantiomer of nateglinide were achieved with Chiralpak AD-H (250 x 4.6 mm, 5 mu m particle size) column using hexane and ethanol (90:10 v/v) as mobile phase at 25 degrees C temperature. Flow rate was kept as 1.0 mL min(-1) and elution was monitored at 210 nm. The effects of the mobile phase composition, the flow rate and the temperature on the chromatographic separation were investigated. Developed method is capable to detect (LOD) and quantitate (LOQ) L-nateglinide to the levels of 0.3 and 1.0 mu g mL(-1) respectively, for 10 mu L injection volume. The percentage RSD of the peak area of six replicate injections of L-nateglinide at LOQ concentration was 5.2. The percentage recoveries of L-nateglinide from D-nateglinide ranged from 97.9 to 99.7. The test solution and mobile phase was found to be stable up to 24 h after preparation. The developed method was validated with respect to LOD, LOQ, precision, linearity, accuracy, robustness and ruggedness.