Rapid determination of ambrisentan enantiomers by enantioselective liquid chromatography using cellulose‐based chiral stationary phase in reverse phase mode

A sensitive, specific, and rapid high‐performance liquid chromatography ( HPLC ) method for the determination of ambrisentan enantiomers has been developed and validated. Six chiral columns were tested in a reversed‐phase system. Excellent enantioseparation with the resolution more than 2.5 was achieved on C hiralcel OZ ‐3 R (cellulose 3‐chloro‐4‐methylphenylcarbamate) using mixture of 20 m M sodium formate (p H 3.0) with acetonitrile (55:45; v/v). Validation of the HPLC method including linearity, limit of detection, limit of quantification, precision, accuracy, and selectivity was performed according to the I nternational C onference on H armonisation ( ICH ) guidelines. The method has an advantage of a very quick chromatographic separation (less than 6 min) and therefore is highly suitable for routine determination of ( R )‐ambrisentan in enantiopure active pharmaceutical ingredient ( S )‐ambrisentan.