''Custom'' synthesis of radioligands for RIA through activated esters. I. Testosterone

Journal Article · Tue Jan 01 00:00:00 EST 1980 · J. Immunoassay; (United States)

DOI:https://doi.org/10.1080/01971528008055780· OSTI ID:5614322

Tantchou, J K; Slaunwhite, Jr, W R

The current method labeling small molecules for radioimmunoassay by coupling iodohistamine to haptens through a mixed anhydride reaction is unacceptable to clinical laboratories. Therefore, we propose the use of a simple two-step procedure: treatment of /sup 125/I-2-iodohistamine with the activated ester of a small molecule followed by thin layer chromatography to remove unlabeled ligand. Only one radioactive substance, /sup 125/I-2-iodohistamine, need be stocked, and the availability of labeled ligands is limited only by the number of nonradioactive activated esters. This principle is illustrated by the use of testosterone. N-Hydroxysuccinimidyl esters of testosterone hemisuccinate and of testosterone-3-carboxymethyloxime were coupled to 2-iodohistamine, /sup 125/I-2-iodohistamine or to /sup 125/I-2,5-diiodohistamine. Optimum conditions required reaction of 20-50 fold molar excess of ester in 75 microL of tetrahydrofuran with iodohistamine in 75 microL of buffer at pH 8.5 for 30 min at 4 degrees. The reaction mixture was applied directly to a pre-absorbent TLC plate coated with silica gel and run in the system, benzene:ethanol:acetic acid, 75:24:1 (v:v:v). The desired radioligand was eluted in 85% yield.

• OSTI ID: 5614322
• Journal Information: J. Immunoassay; (United States), Vol. 1:1
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
59 BASIC BIOLOGICAL SCIENCES
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
IODINE 125
RADIOPHARMACEUTICALS
CHEMICAL PREPARATION
CHEMICAL REACTION YIELD
ESTERS
HISTAMINE
LABELLING
LIGANDS
RADIOIMMUNOASSAY
TESTOSTERONE
AMINES
ANDROGENS
ANDROSTANES
AZOLES
BETA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HETEROCYCLIC COMPOUNDS
HORMONES
HYDROXY COMPOUNDS
IMIDAZOLES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
LABELLED COMPOUNDS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
RADIOASSAY
RADIOISOTOPES
STEROID HORMONES
STEROIDS
SYNTHESIS
TRACER TECHNIQUES
YIELDS
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques
400702 - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials