title: Production, quality control, biodistribution assessment and preliminary dose evaluation of (177)Lu-PDTMP as a possible bone palliative agent.
abstract: OBJECTIVE
  In this study, production, quality control, and biodistribution studies of a newly developed therapeutic compound have been presented and are followed by dosimetric evaluation for use in humans based on biodistribution data in wild-type rats.
  
  
  METHODS
  The Lu-1,2-propylene di-amino tetramethylenephosphonic acid (Lu-PDTMP) complex was prepared successfully using synthesized PDTMP ligand and LuCl3. LuCl3 was obtained by thermal neutron irradiation (4×10 n/cm/s) of enriched Lu2O3 samples. The radiochemical purity of Lu-PDTMP was checked by instant thin-layer chromatography. Stability studies of the complex in the final preparation and in the presence of human serum were performed for up to 72 h. The biodistribution of Lu-PDTMP and LuCl3 in wild-type rats was checked in animal tissues for up to 7 days. The absorbed dose of each human organ was calculated by means of the medical internal radiation dose method.
  
  
  RESULTS
  Lu was produced with a specific activity of 100-110 GBq/mg. Lu-PDTMP was prepared with high radiochemical purity of greater than 99% and specific activity of 278 GBq/mmol. The complex demonstrated significant stability at room temperature. The agent demonstrated major accumulation in the bone tissue and a high target/nontarget uptake ratio. Dosimetric results showed that all tissues receive an insignificant absorbed dose in comparison with bone tissue.
  
  
  CONCLUSIONS
  The results showed that Lu-PDTMP has considerably better properties compared with clinically used bone-seeking radiopharmaceuticals and therefore can be a good candidate for bone pain palliative therapy in skeletal metastases; however, further biological studies in other mammals are still needed.
authors.affiliation: Radiopharmaceutical Research and Development Lab (RRDL), Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Yousefnia
authors.forename: Amir R
authors.initials: AR
authors.lastname: Jalilian
authors.forename: Samaneh
authors.initials: S
authors.lastname: Zolghadri
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghannadi-Maragheh
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000528:radiation effects*; D004164:Diphosphonates / Q000737:chemistry / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D006801:Humans; D008187:Lutetium / Q000627:therapeutic use*; D059408:Pain Management / Q000379:methods*; D010166:Palliative Care / Q000379:methods*; D011786:Quality Control; D011854:Radiochemistry; D011868:Radioisotopes / Q000627:therapeutic use*; D011874:Radiometry; D051381:Rats; D014018:Tissue Distribution
chemical_list: D004164:Diphosphonates; D011868:Radioisotopes; C417557:propylenediaminetetramethylene phosphonate; D008187:Lutetium