title: Analytics of the therapeutic peptide aviptadil by sheathless CE-MS and comparison with nanoRP-HPLC-MS.
abstract: Purification and quality control of therapeutic peptides is often performed by one single method, RP-HPLC. As usage of an orthogonal technique is highly advisable for quality assurance, capillary electrophoresis (CE) employing a coated capillary coupled via a sheathless interface to a mass spectrometer was applied in parallel. The basic therapeutic peptide aviptadil served as a model substance to study the impurity profiles revealing 15 detectable impurities using CE-MS, two were detected by an appropriate nanoRP-HPLC-MS method. None of the impurities detected by CE were observed in LC and vice versa. The LOD in CE-MS was determined in the base peak electropherogram at ∼1fmol, a value 2500 times smaller than the LOD found in nanoRP-HPLC-MS (3pmol). In nanoRP-HPLC-MS only 0.2% of the extrapolated CE-MS signal for a 25ng aviptadil load was observed. We conclude that both, the LOD as well as the impurity profile of aviptadil, as analyzed by nanoRP-HPLC are influenced by both, the ligand-derivatized silica matrix and the flow-rate. Peptides may disappear completely and their variable emergence may lead to the determination of incorrect ratios as present in the sample.
authors.affiliation: Biotech Processes and Analytics Department, PharmBioTec GmbH, D-66123 Saarbrücken, Germany. Electronic address: p.gross@pharmbiotec.de.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gross
authors.forename: Sonja C
authors.initials: SC
authors.lastname: Burkart
authors.forename: Rolf
authors.initials: R
authors.lastname: Müller
mesh_terms: D000327:Adsorption; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D004338:Drug Combinations; D004563:Electrochemistry; D019075:Electrophoresis, Capillary; D006801:Humans; D008024:Ligands; D057230:Limit of Detection; D016014:Linear Models; D013058:Mass Spectrometry; D010100:Oxygen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010646:Phentolamine / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
chemical_list: D004338:Drug Combinations; D008024:Ligands; D010455:Peptides; D014660:Vasoactive Intestinal Peptide; D012822:Silicon Dioxide; C438273:aviptadil; D010100:Oxygen; D010646:Phentolamine
keywords: Quality control; Sheathless CE-MS; Therapeutic peptides; Unspecific peptide adsorption; nanoLC-MS