Radioiodination and astatination of octreotide by conjugation labeling

Published

Journal Article

Octreotide was coupled to 3-iodobenzoyl and 3-iodonicotinoyl moieties to obtain [N-(3-iodobenzoyl)-D-Phe1]octreotide (IBO) and [N-(3-iodonicotinoyl)-D-Phe1]octreotide (INO), respectively. The IC50 values for the binding of IBO and INO to CA20948 rat pancreatic tumor membranes were 0.90 and 0.13 nM, respectively, compared with 0.35 nM for octreotide itself. Starting from N-succinimidyl 3-[131I]iodobenzoate and N-succinimidyl 5-[131I]iodopyridine-3-carboxylate, [131I]IBO and [131I]INO were prepared in overall radiochemical yields of 35%-50%. Likewise, {N-(3-[11At]astatobenzoyl)-D-Phe1}octreotide ([211At]ABO) was prepared in similar yield from N-succinimidyl 3-[211At]astatobenzoate. In vitro assays with AR42J rat pancreatic tumor cells demonstrated a higher retention of cell-internalized radioiodine activity for [131I]INO compared with [125I]IBO. Tissue distribution studies with both conjugates revealed low levels of activity in the thyroid suggesting that dehalogenation of these peptides was minimal. (C) 2000 Elsevier Science Inc.

Duke Authors

Cited Authors

  • Vaidyanathan, G; Affleck, D; Welsh, P; Srinivasan, A; Schmidt, M; Zalutsky, MR

Published Date

  • February 29, 2000

Published In

Volume / Issue

  • 78 / 3

Start / End Page

  • 329 - 337

International Standard Serial Number (ISSN)

  • 0162-0134

Citation Source

  • Scopus