title: Synthesis and preliminary biological evaluation of (3-iodobenzoyl)norbiotinamide and ((5-iodo-3-pyridinyl)carbonyl)norbiotinamide: two radioiodinated biotin conjugates with improved stability.
abstract: A new class of radioiodinated biotin conjugated is described in which the amido bond between biotin and the labeled prosthetic group is reversed. One conjugate, (3-[125I]iodobenzoyl)norbiotinamide (4c, [125I]IBB) was labeled with Na125I in one step from (3-(tributylstannyl)benzoyl)norbiotinamide (4b, TBB) via a demetalation reaction. However, the analogous reaction with ((5-(tributylstannyl)-3-pyridinyl)carbonyl)norbiotinamide (6b, TPB) failed to yield ((5-[131I]iodo-3-pyridinyl)carbonyl)norbiotinamide (6c, [131I]IPB, necessitating a two-step approach for synthesizing [131I]IPB. The binding of [125I]IBB and [131I]IPB to streptavidin in vitro was identical to that of biotinyl-3-[125I]iodoanilide, a conjugate with an amido bond with normal configuration. Both [125I]IBB and [131I]IPB were stable in serum while the first-generation compound was rapidly degraded. The biodistribution patterns of [125I]IBB and [131I]IPB in mice are consistent with limited degradation of these conjugates by biotinidase and deiodinases.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710, USA. cfoulon@acpub.duke.edu
authors.forename: C F
authors.initials: CF
authors.lastname: Foulon
authors.forename: K L
authors.initials: KL
authors.lastname: Alston
authors.forename: M R
authors.initials: MR
authors.lastname: Zalutsky
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D001710:Biotin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D004355:Drug Stability; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000493:pharmacokinetics; D019809:Streptavidin; D014018:Tissue Distribution
chemical_list: C106665:((5-iodo-3-pyridinyl)carbonyl)norbiotinamide; C106664:(3-iodobenzoyl)norbiotinamide; D001426:Bacterial Proteins; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D001710:Biotin; D019809:Streptavidin