Separation and identification of peptide mixtures in a synthesis crude of carbetocin by liquid chromatography/electrospray ionization mass spectrometry

In order to separate and characterize the target peptide and the side-product peptide compounds of a synthesis crude of the peptide hormone carbetocin, liquid chromatography coupled to high-flow electrospray ionization mass spectrometry (LC/eS-MS) has been used. Carbetocin is an important drug with recognized therapeutical application for stimulation of uterine contractions to facilitate parturition. Stepwise solid phase peptide synthesis (SPPS) commonly results in unwanted side products associated with incomplete peptide chains. Consequently, this procedure requires extensive purification and characterization of the final synthesis crude. The linear solvation energy relationship (LSER) method has been applied to optimize the proportion of organic modifier of the mobile phase used in the established LC method. On the other hand, ES-MS has allowed rapid and reliable identification of the target peptide and the other impurities present in the carbetocin synthesis products.