Abstract |
To develop 131I-labelled m-iodobenzylguanidine (1311-
MIBG), various experiments such as synthesis of MIBG,
establishment of labelling conditions, determination of
radiochemical purity, and examination of stability were
carried out. 1) m-Iodobenzylguanidine (MIBG) sulfate
was synthesized with a total yield of 62.4% by the
condensation of m-iodobenzylamine hydrochloride with
cyanamide via MIBG bicarbonate. Its physical
properties, IR, 1H-NMR, and elemental analysis data
were nearly identical to those of literature. 2)
Freeze-dried or vacuum-dried kit vials were prepared
from the mixture so as to contain MIBG (2 mg), ascorbic
acid (10 mg), copper (II) sulfate (0.14 mg), and tin
(II) sulfate (0.5 mg) per vial. Copper (I) catalyzed
radioiodination of MIBG was carried out using kit vials
and 0.01 M H2SO4 as solvent at 100℃ for 30 min under
nitrogen atmosphere (optimal conditions). Labelling
yield was 98% and radiochemical purity was 99.5%,
respectively. 3) Solid-phase radioiodination of MIBG
was carried out at 155℃ for 30 min using the prepared
vials to contain MIBG (2 mg) and ammonium sulfate (10
mg). Duplicate reactions under the same conditions
showed labelling yield of 95% and radiochemical purity
of 99.5%. MIBG prepared either by catalytic or by
solid-phase exchange method showed radiochemical purity
of 99% even after 3 days storing at room temperature. |