Fundamental study of enantioselective HPLC separation of tapentadol enantiomers using cellulose-based chiral stationary phase in normal phase mode.

A sensitive and specific high performance liquid chromatography method for the separation and determination of tapentadol enantiomers has been developed and validated. Ten different chiral columns were tested in a normal phase system. Excellent enantioseparation with the resolution more than 2.5 for all enantiomers was achieved on Chiralpak AD-H using mixture of heptane-propan-2-ol-diethylamine (980:20:1, v/v/v). The detection was carried out using fluorescence detector at excitation wavelength of 295 nm and emission wavelength of 273 nm. The influence of mobile phase composition, namely organic modifiers, additives, aliphatic alkanes and water content in mobile phase, on retention and enantioseparation was studied. Validation of the developed method including linearity, limit of detection, limit of quantification, precision, accuracy and selectivity was performed according to the International Conference on Harmonization guidelines. The advantage of the method is a good enantioseparation, short analysis time (less than 20 min) and therefore this method is suitable for routine determination of chiral purity of (R,R)-tapentadol in enantiopure active pharmaceutical ingredient.