Development of a new method based on chiral ligand-exchange chromatography for the enantioseparation of propranolol

A new chromatographic procedure was proposed for the separation of propranolol (PRN) enantiomers based upon enantioselective chiral ligand-exchange chromatography. The separation was carried out on a short C8 column leading to considerably short separation time. L-alanine and Cu2 were applied as chiral selector and central bivalent complexing ion, respectively. It was found that the kind of copper salt could influence the enantioseparation efficiency. The separation on the C8 stationary phase was more efficient than that on the C18 column. It was shown that the pH of mobile phase, organic modifier content of mobile phase, mole ratio of chiral ligand to bivalent ion and Cu(L-alanine)2 concentration in the mobile phase were important in enantioseparation efficiency. Water/methanol (70:30) mixture containing L-alanine-Cu2 (7:1) was found to be the best mobile phase condition for PRN enantioseparation. All effective parameters were optimized in order to improve the separation efficiency. The optimized HPLC method was utilized for analysis of propranolol enantiomers in spiked human blood plasma samples.