Determination of enantiomeric impurity of etodolac by capillary electrophoresis using (2-hydroxypropyl)-beta-cyclodextrin.

A capillary electrophoresis method was developed to determine the impurity of etodolac enantiomers. (2-Hydroxypropyl)-beta-cyclodextrin (HP-beta-CD) was used as a chiral selector and ketoprofen as an internal standard to improve the peak area precision. The seperation of the etodolac enantiomers was achived within 35 min at 15 degrees C and its highest resolution was about 4.0 using phosphate buffer (0.1 M, pH 6.0) with 15 mM HP-beta-CD and UV detection at 225 nm with a reference wavelength at 360 nm. This method allowed determination of 0.2% of (R)-(-)-etodolac in (S)-(+)-etodolac and method validation showed adequate linearity over the required range.