title: An LC-MS/MS assay to determine plasma pharmacokinetics of cyclic thymic hexapeptide (cTP6) in rhesus monkeys.
abstract: A robust and simple method for absolute quantification of a novel bidirectional immunomodulatory drug candidate, cyclic thymic hexapeptide (cTP6), in rhesus monkey plasma was developed and validated by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Plasma proteins were precipitated by adding four volumes of acetonitrile. Peptides in the supernatant were separated by liquid chromatography on an Agilent Zorbax Eclipse Plus-C18 chromatographic column with gradient elution using 0.1% formic acid in water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B) at 0.2 mL/min. The analytes were identified by triple quadrupole mass spectrometry in positive ion-mode. The assay was linear over a concentration range of 10-5000 ng/mL for cTP6, with a lower limit of quantification (LLOQ) of 10 ng/mL. Intra- and inter-day precision of the assay at three concentrations were 1.51-7.70% with accuracy of 95.1-104.2%. The average recovery of cTP6 for three concentration levels was 59.6-64.0%. No significant matrix effect was observed. Peptide cTP6 was detected in plasma of live rhesus monkeys up to 6-8h after intra-muscular injection. The half-life was 2.24-2.95 h. The result revealed a nonlinear pharmacokinetic response to increasing doses of cTP6 (100, 200, 500 μg/kg). For the multiple dose study of cTP6, the drug did not accumulate during daily administration at 100 μg/kg for 7 consecutive days in rhesus monkeys.
authors: Beijing Institute of Technology, No.5 South Zhongguancun Street, Haidian District,Beijing 100081, PR China.
authors: Qingfang
authors: Q
authors: Meng
authors: Zhihang
authors: Z
authors: Chen
authors: Jinjing
authors: J
authors: Che
authors: Yiping
authors: Y
authors: Lu
authors: Huanzhang
authors: H
authors: Wang
authors: Chengqi
authors: C
authors: Shan
authors: Yunan
authors: Y
authors: Hou
authors: Hongjiao
authors: H
authors: Shi
authors: Yangjun
authors: Y
authors: Zhang
authors: Junying
authors: J
authors: Wei
authors: Xiaohong
authors: X
authors: Qian
authors: Hongwei
authors: H
authors: Peng
authors: Yuanguo
authors: Y
authors: Cheng
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D007273:Injections, Intramuscular; D008253:Macaca mulatta / Q000097:blood*; D009842:Oligopeptides / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D016305:Thymopentin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D009842:Oligopeptides; D016305:Thymopentin