title: Quantification of endostar in rat plasma by LC-MS/MS and its application in a pharmacokinetic study.
abstract: LC-MS/MS is a promising analytical platform for the quantification of recombinant therapeutic proteins in biological fluids for pharmacokinetic (PK) studies. Herein, an absolute quantification method based on LC-MS/MS technique was developed to quantify endostar, which is modified from the recombinant human endostatin by adding a nine-amino acid sequence (MGGSHHHHH) at the N-terminal. A reproducible three-step analytical procedure was adopted: (1) Ni(2+) Sepharose was used to selectively extract endostar; (2) the signature peptide "TEAPSATGQASSLLGGR" (m/z 802.3(2+)-651.8(2+)) of endostar and a synthetic peptide "TEAPSATGQVSSLLGGR" (m/z 816.9(2+)-666.4(2+)) as internal standard (IS) were selected and analyzed in the multiple reaction monitoring (MRM) mode; (3) the proposed method was validated and applied to the pharmacokinetic study of endostar. The lower limit of quantification (LLOQ) for quantifying endostar was 50 ng/ml and this method is linear over 50-10,000 ng/ml. The accuracy was between 85% and 115%, and the intra-batch and inter-batch analytic precision and accuracy were below 15%. This LC-MS/MS approach was validated for the application to the pharmacokinetic study of endostar in rats.
authors.affiliation: State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, No. 24, Tongjiaxiang Street, Nanjing 210009, China.
authors.forename: Ying Chun
authors.initials: YC
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.forename: Zhi Yuan
authors.initials: ZY
authors.lastname: Tang
authors.forename: Ya Nan
authors.initials: YN
authors.lastname: Xiao
authors.forename: Hai Ping
authors.initials: HP
authors.lastname: Hao
authors.forename: Guang Ji
authors.initials: GJ
authors.lastname: Wang
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D000818:Animals; D002138:Calibration; D002853:Chromatography, Liquid / Q000592:standards; D004355:Drug Stability; D043169:Endostatins / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000097:blood / Q000493:pharmacokinetics; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012685:Sepharose / Q000031:analogs & derivatives / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D020533:Angiogenesis Inhibitors; D043169:Endostatins; D011994:Recombinant Proteins; D012685:Sepharose; C522911:endostar protein