Abstract

A validated LC method for the enantiomeric separation of ambrisentan in bulk drug and pharmaceutical dosage forms

Author(s): Ravi Kiran Kaja, K.V.SurendhraNath, K.Babuji , P.V.V.Satyanarayana,K.Suresh Kumar

A new and accurate chiral liquid chromatographic method has been developed for the separation ofAmbrisentan and its (R)-enantiomer in bulk drugs and pharmaceutical dosage forms. Normal phase chromatographic separation was performed on an immobilized cellulose based chiral stationary phase (Chiralpak-ADH) with n-hexane: ethanol (85:15, v/v) asmobile phase at a flowrate of 1.0mLmin-1. The elution timewas approximately 15min. The resolution (Rs) between the enantiomers was greater than 3.0. The limit of detection (LOD) and limit of quantification (LOQ) for the (R)-enantiomer were 0.03 µg and 0.1 g respectively, for a 10 L injection volume. The linearity of themethod for the (R)-enantiomer was excellent (r2>0.999) over the range from LOQ to 0.3%. Percentage recovery of the (R)-enantiomer frombulk drug samples and pharmaceutical dosage forms ranged from98.5- 101.2% indicative of the high accuracy of the method. Robustness studies were also conducted. The sample solution stability and mobile phase stability studies were determined and the results were found to be satisfactory for a study period of 48 h.