Premium
Comparison of the precipitation methods (ammonium sulphate and trichloroacetic acid) to evaluate the in vivo binding of 99m Tc‐MDP on blood constituents
Author(s) -
Freitas R. S.,
Gomes M. L.,
Mattos D. M.,
Moreno S. R.,
Feliciano G. D.,
Lima E.,
LimaFilho G. L.,
Penas M. E.,
Orlando M. M. C.,
BernardoFilho M.
Publication year - 2001
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.25804401216
Subject(s) - trichloroacetic acid , chemistry , biodistribution , in vivo , ammonium , precipitation , chromatography , radiochemistry , biochemistry , in vitro , organic chemistry , physics , microbiology and biotechnology , meteorology , biology
The determination of the radiopharmaceutical binding on blood constituents is worthwhile to understand the biodistribution and to dosimetric considerations. We studied this binding of the Tc‐99m methylenediphosphonic acid ( 99m Tc‐MDP) used to bone evaluation. This radiopharmaceutical was administrated in Wistar rats and after 5 min, blood was withdrawn with anticoagulant. The samples were centrifuged, plasma (P) and blood cells (BC) separated, precipitated with trichloroacetic acid (TCA) or ammoniun sulfate (AS) in various concentrations (0.1, 0.5, 1.0, 5.0, 10 and 20%) and soluble (SF) and insoluble fractions (IF) isolated. The percent of radioactivity (% ATI) in the fractions was determined. The % ATI on P was 84.58 ± 8.16 and on BC was 15.39 ± 8.17. Concerning to TCA, (i) the highest % ATI in IF‐P was from (40.64 ± 9.81) to the 5.0% TCA concentrations and (ii) on IF‐BC, % ATI decreased significantly (p<0.01) from (78.08 ± 7.58 to 66.98 ± 8.40) with the used TCA concentrations. The % ATI, when AS was used on (a) IF‐P was not modified by the AS concentrations, and (b) on IF‐BC varied from 77.46 ± 3.47 to 38.03 ± 8.76 respectively with the AS concentrations from 0.1. to 10.0%. We can speculate that the binding of the studied radiopharmaceutical to blood elements and the precipitation effect may depend on the chemical characteristics of the radiopharmaceutical studied and the mechanisms involved in its fixation on the blood elements.