[Hygienic standardization of tin level in the air]. / Materialy k gigienicheskomu reglamentirovaniiu soderzhaniia olova v atmosfernom vozdukhe.

Indices reflecting the functional state of the central nervous system, peripheral blood, enzymes and gonads were used in accordance with the toxico-dynamics of substances. Besides, body mass, behavior of animals, pathomorphological and histochemical indices were studied. 5 concentrations of tin chloride were studied: 400, 80, 15, 3 and 0.5 mg/m3. On the basis of an acute experiment (6-1440 h) it has been established, that the concentration-time relationship according to a number of biochemical and physiological parameters on the graph was expressed by direct lines on the double log scale with angles to abscissa from 124.9 degrees (according to blood transaminase activity reduction) up to 138.2 degrees, which allowed to determine the class of danger, safety and cumulation coefficients, threshold and no-effect concentrations of tin chloride under inhalational exposure to it. The lowest no-effect concentration 0.05 mg/m3 is recommended as an average 24-hour MAC and approved by the USSR Public Health Ministry.

Determination of radiochemical purity and pharmacokinetic parameters of 99mTc-sulphur colloid and 99mTc-tin colloid.

Labelling yield and radiochemical purity, higher than 95%, of 99mTc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in 99mTc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of 99mTc-colloid preparations excreted by urine is 99mTcO-, the remaining past 50% being protein bound 99mTc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in 99mTc-S-colloid and 160 min in 99mTc-Sn colloid.

The paper spot test: a rapid method for quantitating stannous concentrations in radiopharmaceutical kits.

We have developed a simplified, semiquantitative test for the determination of stannous tin in pyrophosphate and other tin-containing radiopharmaceuticals, excluding those stabilized with ascorbic acid and MAA preparations. The test involves the formation and disappearance of a positive red color complex in the presence of Sn(II) and in acidified porphyrin solution. With this technique, the time of spot disappearance is directly proportional to the Sn(II) concentration spotted. The procedure is easy to use, requiring only a high-intensity light source (30-watt light bulb) and a timing device. The test is accurate, reproducible, and sensitive to Sn(II) levels as low as 40 micrograms/ml. Because the procedure is rapid (requiring less than 5 min), it can easily be incorporated into the routine radiopharmaceutical quality-control program of any nuclear medicine facility.

99mTc-DTPA(Sn) dry-kit preparation. Quality control and clearance studies.

The preparation technique for 99m-Tc-DTPA(Sn)-complex has been studied in detail in order to find the optimal conditions for preparation. The concentration of DTPA should be at least 10 mM, and that of Sn(II) less than 1 mM, in order to obtain a reproducible high-labelling yield. A dry sterile kit was prepared of 39.3 mg H-5DTPA and 2.3 mg SnCl-2 with 2H-2O in a 10 ml vial. The 99m-Tc-DTPA(Sn) was prepared by adding the 99m-Tc-eluate to the vial. After 1 min the solution was sterile-filtered and was ready for use. The plasma clearance of 99m-Tc-DTPA(Sn) in man determined by blood-sampling up to 200 minutes after administration shows a good correlation to endogenous creatinine clearance (r plus 0.93). The plasma disappearance curve studied during 24 h is, however, a sum of three exponentials corresponding to biological half-times of 18 plus or minus 8 min, 105 plus or minus 9 min and 17 plus or minus 4 h. The slow third component representing about 2% is assumed to be due to binding of 99m-Tc to plasma proteins. The absorbed radiation dose calculated for whole body is 8 mrad/mCi, kidneys 50 mrad/mCi, bladder 300 mrad/mCi, ovaries 17 mrad/mCi and testes 11 mrad/mCi. This agent is a valuable radiopharmaceutical for renovascular clinical problems. Scintigraphic imaging of the aorta, kidneys, ureters and bladder (for residual urinary volume-determination) could be performed.