title: MALDI-MS analysis and theoretical evaluation of olanzapine as a UV laser desorption ionization (LDI) matrix.
abstract: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) being soft ionization technique, has become a method of choice for high-throughput analysis of proteins and peptides. In this study, we have explored the potential of atypical anti-psychotic drug olanzapine (OLZ) as a matrix for MALDI-MS analysis of peptides aided with the theoretical studies. Seven small peptides were employed as target analytes to check performance of olanzapine and compared with conventional MALDI matrix α-cyano-4-hydroxycinnamic acid (HCCA). All peptides were successfully detected when olanzapine was used as a matrix. Moreover, peptides angiotensin Ι and angiotensin ΙΙ were detected with better S/N ratio and resolution with this method as compared to their analysis by HCCA. Computational studies were performed to determine the thermochemical properties of olanzapine in order to further evaluate its similarity to MALDI matrices which were found in good agreement with the data of existing MALDI matrices.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan; Dr. Panjwani Centre for Molecular Medicine and Drug Research, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan. Electronic address: musharraf1977@yahoo.com.
authors.forename: Syed Ghulam
authors.initials: SG
authors.lastname: Musharraf
authors.affiliation: H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan.
authors.forename: Mariam
authors.initials: M
authors.lastname: Ameer
authors.affiliation: H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan.
authors.forename: Arslan
authors.initials: A
authors.lastname: Ali
mesh_terms: D000818:Animals; D001569:Benzodiazepines / Q000737:chemistry*; D001665:Binding Sites; D002138:Calibration; D003373:Coumaric Acids / Q000737:chemistry; D007834:Lasers; D008956:Models, Chemical; D008968:Molecular Conformation; D008970:Molecular Weight; D000077152:Olanzapine; D010455:Peptides / Q000737:chemistry; D011522:Protons; D012984:Software; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013552:Swine; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D003373:Coumaric Acids; D010455:Peptides; D011522:Protons; D001569:Benzodiazepines; C007175:alpha-cyano-4-hydroxycinnamate; D000077152:Olanzapine
keywords: MALDI matrices; Olanzapine; Peptides; Thermochemical properties; ab-initio molecular orbital calculations