title: Radiochemical purity, at expiry, and radiochemical stability of iodine-131 labelled meta-iodobenzylguanidine concentrates for intravenous infusion.
abstract: OBJECTIVE
  The determination of the amount of free [131I]iodide in [131I]metaiodobenzylguanidine ([131I]MIBG) concentrates for intravenous infusion under different storage conditions derived from daily practice.
  
  
  METHODS
  The percentage of free [131I]iodide was determined in [131I]MIBG concentrates (1.6-3.9 GBq in 7.5 ml), kept on dry ice (up to expiry, 3 days after production) or, after thawing, at room temperature (up to 24 h). A validated solid phase extraction (SPE) assay was used.
  
  
  RESULTS
  Free [131I]iodide increased from 1.9% +/- 0.34% at production to 4.4% +/- 0.67% (mean +/- SD; n = 5) at expiry in 3.7 GBq per 7.5 ml [131I]MIBG infusion concentrates stored on dry ice (-78 degrees C). At room temperature, formation of free [131I]iodide was found to be dependent on the radioactive concentration of the fluid. [131I]iodide levels increased from 3.1%, immediately after thawing, to 6.6% and 16.6% at t = 5 and 24 h, respectively, for a 3.9 GBq per 7.5 ml concentrate.
  
  
  CONCLUSIONS
  The investigated formulation of [131I]MIBG concentrates, stored in its original packing containing dry ice, can generally be used up to expiry. After thawing, the undiluted concentrates should be administered to a patient within 3.5 h.
authors.affiliation: Department of Pharmacy, Stotervaart Hospital, Amsterdam, The Netherlands.
authors.forename: A R
authors.initials: AR
authors.lastname: Wafelman
authors.forename: C A
authors.initials: CA
authors.lastname: Hoefnagel
authors.forename: R A
authors.initials: RA
authors.lastname: Maes
authors.forename: J H
authors.initials: JH
authors.lastname: Beijnen
mesh_terms: D019797:3-Iodobenzylguanidine; D004355:Drug Stability; D006801:Humans; D007262:Infusions, Intravenous; D007454:Iodides / Q000032:analysis*; D007457:Iodine Radioisotopes; D007462:Iodobenzenes / Q000008:administration & dosage / Q000737:chemistry / Q000592:standards*; D013696:Temperature; D013997:Time Factors
chemical_list: D007454:Iodides; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019797:3-Iodobenzylguanidine