Formulation and evaluation of a single vial lyophilized preparation of technetium-99m labeled ethylene dicysteine as a renal scintigraphic agent

99mTc labeled N-N-ethylene-L, L-dicysteine (EC) was introduced in form of multiple-step kit as an alternate renal imaging radiopharmaceutical for commonly used 99mTc-MAG3. We developed a single component lyophilized kit of EC ready to be labeled with 99mTc. We present the optimization of the components of our formulation, its evaluation in animal models, normal human volunteers and patients of various renal diseases, in comparison with 99mTc-MAG3. Efficient labeling of EC was achieved with our preparation at pH 7 to 12. The formulation at pH 8 was used further for bio distribution studies in organs of sacrificed Sprague Dawley rats and a live rhesus monkey using scintigraphy. After satisfactory bio-distribution results, the kit was then evaluated in normal human volunteers through renography. But the renogram parameters of 99mTc-EC (pH 8) were statistically inferior to 99mTc-MAG3. Surrogate kit at pH 10 was therefore developed and re-evaluated in rats for organ bio distribution. After favorable results the kit was then assessed further in normal volunteers and a group of patients with various renal disorders via scintigraphy. The EC kit developed at pH 10 gave images better than and scintigraphic parameters comparable to 99mTc-MAG3. It was concluded that single vial kit we formulated easy to prepare than three-vial kit and can be used as an alternate to 99mTc-MAG3.