Chiral separation of tamsulosin by capillary electrophoresis.

Enantiomers of (+/-) 5-[2 (R,S)-{[2-(o-ethoxyphenoxy) ethyl] amino} propyl]-2-methoxy-benzenesulfonamide (tamsulosin, drug frequently used in the treatment of prostate diseases) were separated by capillary electrophoresis (CE). An acidic background electrolyte (BGE) with sulfated-beta-cyclodextrin (S-beta-CD) was used to create a chiral separation environment. Baseline separation of the isomers was achieved during 5 min using cathodic electro-osmotic flow (EOF) (countercurrent mode). The quantification limits were 5.3 x 10(-6) moll(-1) for R-isomer and 5.7 x 10(-6) moll(-1) for S-isomer. The R.S.D. values of peak area were 0.54% for R-isomer and 0.75% for S-isomer. The results achieved enable determination of 0.5% of optical impurity.