title: Improved radioiodination of 1,2-dipalmitoyl-3-IPPA via a tributyltin intermediate.
abstract: 1,2-Palmitoyl-3-[15-(4-iodophenyl)pentadecan-3-oyl]-rac-glycerol (MIPAG) is a new agent for the clinical evaluation of pancreatic lipase activity and has demonstrated promise in preliminary clinical studies with patients affected with pancreatic insufficiency. Iodine-131-MIPAG was initially prepared via thallium-iodide displacement. Because of the need for a simple method which is amendable for the routine clinical use of MIPAG we have investigated the preparation and radioiodination of MIPAG utilizing the tributyltin precursor, 1,2-palmitoyl-3-[15-(4-tributylstannylphenyl)pentadecan-3-oy l]-rac-glycerol (TBT-MIPAG, 2). Compound 2 was prepared via the condensation of 1,2-palmitoyl-rac-glycerol with 15-(4-tributylstannylphenyl)pentadecanoic acid (TBT-PPA) prepared from 4-bromophenylacetylene. Electrophilic radioiodination using peracetic acid with sodium iodide-125 in ethanol at 80 degrees C for 60 min afforded I-125-MIPAG in 65.9% (+/- 11.5%) yield and radiochemical purity of 94% (+/- 3.0%) after C-18 Sep-Pak purification (n = 6). This improved method for radioiodination utilizing TBT-MIPAG now provides radioiodinated MIPAG for routine clinical evaluation.
authors.affiliation: Nuclear Medicine Group, Life Sciences Division, Oak Ridge National Laboratory (ORNL), TN 37831-6229, USA. phm@oml.gov
authors.forename: D W
authors.initials: DW
authors.lastname: McPherson
authors.forename: H
authors.initials: H
authors.lastname: Luo
authors.forename: J
authors.initials: J
authors.lastname: Kropp
authors.forename: F F
authors.initials: FF
authors.lastname: Knapp
mesh_terms: D005227:Fatty Acids / Q000737:chemistry; D005989:Glycerides / Q000737:chemistry; D007457:Iodine Radioisotopes / Q000737:chemistry*; D007462:Iodobenzenes / Q000138:chemical synthesis*; D007553:Isotope Labeling / Q000379:methods; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*; D014220:Trialkyltin Compounds / Q000737:chemistry*; D014280:Triglycerides / Q000138:chemical synthesis*
chemical_list: C400805:15-(4-tributylstannylphenyl)pentadecanoic acid; D005227:Fatty Acids; D005989:Glycerides; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019275:Radiopharmaceuticals; D014220:Trialkyltin Compounds; D014280:Triglycerides; C081586:1,2-dipalmitoyl-3-(15-(4-iodophenyl)pentadecanoyl)-rac-glycerol; C011559:tributyltin; C027735:palmitoyl glycerol