title: Biodistribution and excretion of radioactivity after the administration of 166Ho-chitosan complex (DW-166HC) into the prostate of rat.
abstract: OBJECTIVE
  The objective of this study was to determine the fate of the 166Ho-chitosan complex (DW-166HC) in rats by examining its absorption, distribution and excretion after administration into the prostate.
  
  
  METHODS
  About 100 microCi of DW-166HC [containing 0.1875 mg of Ho(NO3)3.5H2O and 0.25 mg of chitosan] was administered intraprostatically. The level of radioactivity in blood, urinary and faecal excretion, and radioactivity distribution were examined. To determine the effect of chitosan in DW-166HC, 166Ho nitrate alone [0.1875 mg of Ho(NO3)3.5H2O] was administered into the prostate of male rats, and radioactivity distribution was examined using whole-body autoradiography.
  
  
  RESULTS
  After administration of DW-166HC into the prostate, cumulative urinary and faecal excretion over the period 0-72 h was 0.35% and 0.11%, respectively. The radioactivity at the administration site was extremely high at all time points up to 144 h (>98% of injected dose). The small amount of radioactivity which did transfer from the administration site distributed mainly to the liver, spleen, kidney cortex and bone. Compared with the DW-166HC group, the group that received 166Ho nitrate alone displayed three- to fourfold higher levels of radioactivity in the main tissues, including liver, spleen, kidney cortex and bone, at 24 h after administration (P < 0.05).
  
  
  CONCLUSIONS
  The results of this study show clearly that most of the administered DW-166HC remained at the administration site. It is concluded that the chitosan complex may be used to retain 166Ho within a limited area in cancer of the prostate.
authors.affiliation: Pharmacology and Toxicology Lab, Central Research Laboratories, Dong Wha Pharmaceutical Co., Ltd., Anyang, South Korea.
authors.forename: Seung Kyoo
authors.initials: SK
authors.lastname: Seong
authors.forename: Jei Man
authors.initials: JM
authors.lastname: Ryu
authors.forename: Dong Hyuk
authors.initials: DH
authors.lastname: Shin
authors.forename: Eun Jeong
authors.initials: EJ
authors.lastname: Bae
authors.forename: Akiyo
authors.initials: A
authors.lastname: Shigematsu
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Hatori
authors.forename: Junko
authors.initials: J
authors.lastname: Nishigaki
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Kyong Bae
authors.initials: KB
authors.lastname: Park
mesh_terms: D000818:Animals; D001822:Body Burden; D002686:Chitin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000652:urine; D004353:Drug Evaluation, Preclinical; D005243:Feces / Q000737:chemistry*; D006695:Holmium / Q000493:pharmacokinetics* / Q000652:urine*; D007267:Injections; D008297:Male; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000652:urine*; D011467:Prostate / Q000378:metabolism*; D011829:Radiation Dosage; D011868:Radioisotopes / Q000493:pharmacokinetics / Q000652:urine; D011874:Radiometry; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D014915:Whole-Body Counting
chemical_list: C116411:DW 166HC; D009942:Organometallic Compounds; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D002686:Chitin; D006695:Holmium