In vitro and in vivo studies with pentavalent technetium-99m dimercaptosuccinic acid

Lam, A.S.K. and Puncher, M.R.B. and Blower, P.J. (1996) In vitro and in vivo studies with pentavalent technetium-99m dimercaptosuccinic acid. European Journal of Nuclear Medicine, 23 (12). pp. 1575-1582. ISSN 0340-6997. (The full text of this publication is not available from this repository)

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Abstract

The purpose of this investigation was to characterise the in vivo chemistry and binding mechanisms of technetium-99m dimercaptosuccinic acid [Tc-99m(V)DMSA]. Biodistribution was studied in mice by frozen section whole-body autoradiography and microautoradiography in selected tissues. Binding to bone mineral analogues was studied in vitro using various forms of calcium phosphate and hydroxyapatite under varied conditions, Similar studies with Tc-99m-hydroxymethylene diphosphonate (HDP) were also carried out for comparison. The in vivo stability of Tc-99m(V)DMSA was monitored by high-performance liquid chromate graphic analysis of blood and urine samples taken over 24 h from patients injected with the tracer, Whole-body autoradiography shows that Tc-99m(V)DMSA has highest affinity for bone (cortical rather than medullary) in mice. Substantial uptake of the tracer was also observed in the kidney (cytoplasm of cortical renal tubular cells). No specific localisation was observed in the liver at either the microscopic or the macroscopic level. While Tc-99m-HDP bound strongly to calcium phosphates under all conditions, Tc-99m(V)DMSA binding was inhibited in the presence of phosphate and was stronger at pH 6.0 than at pH 7.4. In non-phosphate buffers, however, the binding of Tc-99m(V)DMSA remained high across the pH range 4-7.4. Tc-99m(V)DMSA binds to calcium phosphates chemically unaltered, and no radioactive species other than the three isomers of Tc-99m(V)DMSA were detected in blood or urine samples taken from patients up to 24 h after injection. Tc-99m(V)DMSA is stable in vivo, and no conversion of the complex to other chemical species needs to be invoked to explain its uptake in bone metastases or soft tissue tumour. Bone affinity may be due to reversible binding of the unaltered complex to the mineral phase of bone.

Item Type: Article
Subjects: R Medicine
Divisions: Faculties > Science Technology and Medical Studies > Kent Institute of Medicine and Health Sciences (KIMHS)
Depositing User: R.F. Xu
Date Deposited: 04 Jun 2009 16:16
Last Modified: 04 Jun 2009 16:16
Resource URI: http://kar.kent.ac.uk/id/eprint/19292 (The current URI for this page, for reference purposes)
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