Uptake of 99mTc(5+)-complexes in ischemic myocardial slices and their dissociable ability.
OBJECTIVE
To find how some technetium-complexes to deliver the active species, TcO4(3-), to the target tissue from a dissociable polynuclear Tc5+ species in preserved states in vivo.


METHODS
Effect of dissociation ability of the polynuclear Tc5+ complexes on their accumulation in ischemic myocardium was tested. Ability of dissociation as having an appropriate conformation to become biologically functional after entering the blood circulation was tested using a simple dilution method by thin layer chromatography (TLC) analysis. Various degree of ischemic myocardium slices of rat were incubated with 1/100 diluted 99mTc(5+)-succimer, 99mTc(5+)-GH and 99mTc(5+)-PPi.


RESULTS
The TLC patterns of 99mTc(5+)-GH and 99mTc(5+)-PPi showed the presence of a fast increasing of free Tc-species as dilution degree increased. The relative radioactivity of peak of free pertechnetate (Rf = 0.85-1.0) with 1:500 dilution was: 99mTc(5+)-succimer 0%, 99mTc(5+)-GH 28.1% +/- 1.3%, and 99mTc(5+)-PPi 46.0% +/- 2.9% respectively. The uptake of the myocardium after ischemia for 3 h was 99mTc(5+)-succimer 420% +/- 110% dose/g tissue, 99mTc(5+)-GH 710% +/- 180% dose/g tissue, and 99mTc(5+)-PPi 1295% +/- 390% dose/g tissue respectively.


CONCLUSIONS
The dissociation and myocardial uptake showed: 99mTc(5+)-succimer < 99mTc(5+)-GH < 99mTc(5+)-PPi, the uptake by the ischemic myocardium is positively correlated to their dissociation.
D000818:Animals; D004355:Drug Stability; D066298:In Vitro Techniques; D017202:Myocardial Ischemia / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D013400:Sugar Acids / Q000493:pharmacokinetics*; D016698:Technetium Tc 99m Pyrophosphate / Q000493:pharmacokinetics*