title: [In vivo and in vitro stability of ¹³¹I-Herceptin and its form of existence in the blood of rabbits].
abstract: OBJECTIVE
  To evaluate the in vivo and in vitro stability of (131)I-Herceptin and its form of existence in the blood.
  
  
  METHODS
  Herceptin was labelled with iodine-131 using the Iodogen method. (131)I-Herceptin was stored at 4 degrees celsius for 3, 24, 48, 72 and 96 h, and the radiochemical purity (RCP) was measured by high performance liquid chromatography (HPLC). Five rabbits received injections of (131)I-Herceptin and at 1, 3, 6, 24, 48, 72, 96 and 120 h after the injection, blood samples were taken to measure the RCP of (131)I-Herceptin in the serum, and the radio count of the serum and blood cells was calculated.
  
  
  RESULTS
  The baseline RCP of (131)I-Herceptin was (94.9±2.7)%. The RCP was stable after placement at 4 degrees celsius for not over 72 h (F=15.985, P<0.001), but was significantly lowered to (82.6±2.8)% after preservation for over 72 h (t=9.971, P<0.001). Within the time of 1.0 to 96 h after injection in rabbits, (131)I-Herceptin existed mainly in the serum with a radio count of 81%-87%; 24 h after the injection, the RCP of (131)I-Herceptin in the serum was significantly lowered to (75.4±3.9)% (t=6.564, P<0.001).
  
  
  CONCLUSIONS
  Storage at 4 degrees celsius for no more than 72 h does not obviously affect the activity of (131)I-Herceptin in terms of RCP. After injection in rabbits, (131)I-Herceptin exists mainly in the serum and its radiochemical purity remains stable within 24 h, after which obvious degradation occurs.
authors.affiliation: Department of Nuclear Medicine, Second People's Hospital of Guangdong Province, Guangzhou 510317, China. fanyix06@sohu.com
authors.forename: Yi-xiang
authors.initials: YX
authors.lastname: Fan
authors.forename: Wei-min
authors.initials: WM
authors.lastname: Shi
authors.forename: Kai-ling
authors.initials: KL
authors.lastname: Huang
authors.forename: Qing-zhu
authors.initials: QZ
authors.lastname: Liu
authors.forename: Ke-bin
authors.initials: KB
authors.lastname: Li
authors.forename: Ji-zhen
authors.initials: JZ
authors.lastname: Wu
authors.forename: Rong-cheng
authors.initials: RC
authors.lastname: Luo
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000493:pharmacokinetics*; D001769:Blood / Q000378:metabolism*; D045744:Cell Line, Tumor; D004355:Drug Stability; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D011817:Rabbits; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D000068878:Trastuzumab