title: Preparation and evaluation of rhenium-188-pamidronate as a palliative treatment in bone metastasis.
abstract: OBJECTIVE
  Rhenium-188-hydroxyethylidene diphosphonate (188Re-HEDP) as a first generation bisphosphonate has been widely used for bone seeking radiopharmaceutical in cases of metastatic bone disease. No study has been yet reported on preparing a complex of188Re with pamidronate (3-aminohydroxypropylidene-1,1-bisphosphonic acid) (PMA) as a second generation bisphosphonate. Based on this fact, it was hypothesized that a bone-seeking188Re-PMA radiopharmaceutical could be developed as an agent for palliative radiotherapy of bone pain due to skeletal metastases.
  
  
  METHODS
  Pamidronate was labeled with188ReO4-eluted from the alumina based188W/188Re generator. Labeling was optimized, and radiochemical analysis was performed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Biodistribution of this radioconjugate was evaluated and verified further in mice.
  
  
  RESULTS
  188Re-PMA was prepared successfully in a high labeling yield (˃95%) corresponding to a specific activity of 124MBq/μmol and good in vitro stability, but it is likely to consist of multiple species. In biodistribution studies selective uptake and retention of activity in the skeletal system (0.81±0.25% ID/g and 0.57±0.16 at 4 and 48h in bone post injection respectively) followed by clearance in the soft tissues were observed.
  
  
  CONCLUSIONS
  These results show that due to its biological capabilities it would be advantageous to use188Re-PMA for bone pain palliation therapy.
authors.affiliation: Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), P.O.Box: 14395-836, Tehran, Iran. Electronic address: mgandomkar@aeoi.org.ir.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Erfani
authors.affiliation: School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, P.O.Box: 61357-33184, Ahvaz, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Rahmani
authors.affiliation: School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, P.O.Box: 61357-33184, Ahvaz, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Doroudi
authors.affiliation: Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), P.O.Box: 14395-836, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shafiei
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000556:secondary* / Q000628:therapy*; D004164:Diphosphonates / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007553:Isotope Labeling; D008297:Male; D051379:Mice; D010166:Palliative Care / Q000379:methods*; D000077268:Pamidronate; D011868:Radioisotopes / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D014018:Tissue Distribution
chemical_list: D004164:Diphosphonates; D011868:Radioisotopes; C000615081:Rhenium-188; D012211:Rhenium; D000077268:Pamidronate
keywords: (188)Re-PAM; Bone pain therapy; Pamidronic acid; Radiolabeling