Preparation of a stable /sup 99m/Tc complex of F(ab')/sub 2/-DTPA and its biodistribution in mice

Conference · Sun Jan 01 00:00:00 EST 1984 · J. Nucl. Med.; (United States)

OSTI ID:6854131

Paik, C H; Sahami, M S; Hong, J J; Phan, L N.B.; Reba, R C; Eckelman, W C

F(ab')/sub 2/ fragment was chosen for this study because it is divalent for antigen binding and it physiological t1/2 is suitable for /sup 99m/Tc. For a stable label, the authors used (Fab')/sub 2/-DTPA conjugate. A series of control experiments led the authors to a condition resulting in 85% DTPA-/sup 99m/Tc and 15% stable F(ab')/sub 2/-/sup 99m/Tc in competition with the formation of unstable F(ab')/sub 2/-/sup 99m/Tc. Free DTPA and F(ab')/sub 2/ (3.1 x 10/sup -5/ M, 155 ..mu..g)at a DTPA/F(ab')/sub 2/ ratio of 6 were incubated with Sn/sup 2+/ at a DTPA/Sn/sup 2+/ molar ratio of 1 in 0.1 M acetate buffer at pH 4.5 for 1 hr. This solution was then incubated with /sup 99m/Tc. The same condition was applied for radiolabeling the DTPA moiety of F(ab')/sub 2/-DTPA containing 2 DTPA molecules per F(ab')/sub 2/ and 4 free DTPA. Using the same amount of Sn/sup 2+/, F(ab')/sub 2/ was directly labeled with /sup 99m/Tc. /sup 99m/Tc labeled and affinity-purified F(ab')/sub 2/-DTPa (specific activities of l-2 ..mu..Ci per ..mu..g) containing 2approx. =4 ..mu..Ci was injected into the tail vein of mice in order to study their relative distributions in comparison to affinity purified F(ab')/sub 2/-DTPA-/sup 111/In. Biodistributions in %dose per g of both F(ab')/sub 2/-DTPA-/sup 99m/Tc and F(ab')/sub 2/-DTPA/sup 111/ In were similar: For F(ab')/sub 2/-DTPA-/sup 99m/Tc, lung(2.45), liver(3.28), spleen(2.24), kidney(9.10), bone (2.05), and blood(9.62). For F(ab')/sub 2/-DTPA-/sup 111/In, lung(6.27), liver(3.66), spleen(2.66), kidney(9.34), bone(l.43), and blood(19.67). Tissue accumulation of /sup 99m/Tc from directly labeled F(ab')/sub 2/ was much lower. This supports the hypothesis that stable /sup 99m/Tc labeled F(ab')/sub 2/ fragments of tumor antibody can be prepared by complexing /sup 99m/Tc with DTPA in F(ab')/sub 2/-DTPA conjugates.

• Research Organization: Radiopharmaceutical/Medicinal Chemistry Section. The George Washington Univ. Medical Center, Washington, DC 20037
• OSTI ID: 6854131
• Report Number(s): CONF-840619-; TRN: 87-010822
• Journal Information: J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ANTIBODIES
DIAGNOSTIC USES
LABELLING
DTPA
QUANTITY RATIO
RADIOPHARMACEUTICALS
CHEMICAL PREPARATION
ANTIGENS
INCUBATION
INTRAVENOUS INJECTION
LIVER
LUNGS
MICE
NEOPLASMS
RADIONUCLIDE KINETICS
TECHNETIUM 99
TRACER TECHNIQUES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHELATING AGENTS
DIGESTIVE SYSTEM
DISEASES
DRUGS
GLANDS
HOURS LIVING RADIOISOTOPES
INJECTION
INTAKE
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATORY SYSTEM
RODENTS
SYNTHESIS
TECHNETIUM ISOTOPES
USES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics