title: Time-Dependent Structural Alteration of Rituximab Analyzed by LC/TOF-MS after a Systemic Administration to Rats.
abstract: Therapeutic monoclonal antibodies (mAbs) have heterogeneities in their structures. Multiple studies have reported that the variety of post-translational modifications could affect the pharmacokinetic profiles or pharmacological potencies of therapeutic mAbs. Taking into the account that the structural modification of mAbs would affect the efficacy, it is worth investigating the structural alteration of therapeutic mAbs in the blood and the relationship between their structures and pharmacological effects. Herein, we have developed the method to isolate rituximab from plasma in which endogenous IgGs interfere the detection of rituximab, and successfully developed the analytical method with a liquid chromatograph time-of-flight mass spectrometer to detect the structure of rituximab in plasma with errors less than 30 parts per millions. Eight types of carbohydrate chains in rituximab were detected by this method. Interestingly, time-dependent changes in carbohydrate chains such as AAF (G2F) and GnGn (G0) were observed in rats, although the amino acids were stable. Additionally, these structural changes were observed via incubation in plasma as in the rat experiment, suggesting that a certain type of enzyme in plasma caused the alterations of the carbohydrate chains. The present analytical methods could clarify the actual pharmacokinetics of therapeutic mAbs, and help to evaluate the interindividual variations in pharmacokinetics and efficacy.
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Otani
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.|Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Atushi
authors.identifier: http://orcid.org/0000-0002-8057-6768
authors.initials: A
authors.lastname: Yonezawa
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.|Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuda
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imai
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Ikemi
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Omura
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.|Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Yano
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Matsubara
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D002241:Carbohydrates / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D003165:Complement System Proteins / Q000276:immunology; D013058:Mass Spectrometry / Q000379:methods*; D017208:Rats, Wistar; D000069283:Rituximab / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry* / Q000302:isolation & purification; D013997:Time Factors
chemical_list: D002241:Carbohydrates; D000069283:Rituximab; D003165:Complement System Proteins