Abstract
1844
Objectives This study aimed to evaluate the biodistribution, radiation dosimetry, and acute toxicity of 99mTc-DTPA-glipizide (DTPA-GLP) in rats.
Methods DTPA dianhydride conjugated with GLP in dimethylsulfoxide, yielded 60%. Biodistribution and planar images were obtained at 30-120 min after injection of 99mTc-DTPA-GLP (1 mg/rat) in healthy female Fischer 344 rats. Acute toxicity was studied with Fischer 344 male and female rats injected intravenously with 99mTc-DTPA-GLP (3, 10 mg/rat, 11.1 MBq/rat). Toxicity was evaluated by determination of biochemistry parameters. Radiation dosimetry projections in humans were estimated on the basis of the residence times in rats by use of the MIRDose 3.1 software package.
Results Structure of DTPA-GLP was confirmed by NMR, mass spectrometry and HPLC. Radiochemical purity assessed by ITLC was > 96%. 99mTc-DTPA-GLP showed increased pancreas-to-muscle ratios whereas 99mTc-DTPA showed decreased ratios at various time-points. Pancreas could be visualized with 99mTc-DTPA-GLP in normal rat, whereas no uptake in the pancreas was observed in rats pretreated with streptozotocin. Biochemistry results (ALT and AST, bilirubin, BUN, creatinine, and glucose levels) remained within or close to the normal ranges. The projected effective dose equivalent in humans was 0.0113 rem/mCi. Thehighest absorbed doses would be received by the kidney (0.0669 rem/mCi).
Conclusions 99mTc-DTPA-GLP is safe and feasible to assess pancreas beta cell receptor recognition.
- © 2009 by Society of Nuclear Medicine