Direct Enantioseparation of Lorlatinib Enantiomers by Liquid Chromatography on a Chiralpak IB Column

Enantiomeric forms of many drugs are known to have different physiological and therapeutic effects. Previous studies indicated that the inhibitory activity of an enantiomer of Lorlatinib on L1196M kinase was 300 times lower than that of Lorlatinib. In this study, an analytical method for the enantioseparation of Lorlatinib was established on a Chiralpak IB column. Baseline separation was obtained within 10 min using v(n-hexane): v(2-propanol): v(diethylamine) = 85:15:0.1 as mobile phase, and a resolution higher than 2.2. Various factors of HPLC such as the effect of chiral columns, the contents of mobile phase and column temperature were thoroughly investigated. Calibration curves were plotted within the concentration range between 10 and 1000 mu g mL-1 (n = 8), and recoveries between 97.86% and 100.99% were obtained, with a relative standard deviation (RSD) lower than 1.6%. The LOD and LOQ for Lorlatinib were 10.34 and 34.49 mu g mL-1, respectively, and those for its enantiomer were 11.76 and 39.21 mu g mL-1, respectively. Validating factors such as the accuracy, precision, linear relationship, and LOD/LOQ confirmed that the method has the advantages of high efficiency, accuracy and stability and can be used to detect the enantiomeric purity of Lorlatinib. In addition, the chiral recognition mechanisms were discussed according to the thermodynamic parameters and simulation studies between racemates and CSPs.