Technetium Tc 99m Disofenin Injection
» Technetium Tc 99m Disofenin Injection is a sterile, aqueous solution, suitable for intravenous administration, of disofenin that is labeled with 99mTc. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of 99mTc as a disofenin complex, expressed in megabecquerels (microcuries or millicuries) per mL at the time indicated on the labeling. It contains a suitable reducing agent.
Packaging and storage Preserve in single-dose or in multiple-dose containers sealed under a suitable inert atmosphere.
Labeling Label it to include the following, in addition to the information specified for Labeling under Injections 1: the time and date of preparation; the amount of 99mTc as expressed as total megabecquerels (microcuries or millicuries) and concentration as megabecquerels (microcuries or millicuries) per mL at the time of preparation; the expiration date and time; and a statement CautionRadioactive Material. The labeling indicates that in making dosage calculations, correction is to be made for radioactive decay, and also indicates that the radioactive half-life of 99mTc is 6.0 hours.
pH 791: between 4.0 and 5.0.
Radiochemical purity The determination of radiochemical purity for this Injection requires the use of two separate chromatography systems.
System A Apply a measured volume of Injection, appropriately diluted, such that it provides a count rate of about 20,000 counts per minute, about 13 mm from one end of a 10- × 51-mm thin-layer chromatographic strip impregnated with silica gel (see Chromatography 621), and immediately develop the chromatogram over a suitable period by ascending chromatography, using methanol as the solvent. Allow the chromatogram to dry. Cut the chromatogram in two along a line about 13 mm from the top. Place the top and bottom strips into separate counting containers. Determine the radioactivity of each, using a suitable ionization chamber. Hydrolyzed Tc 99m and technetium-tin colloid are located at the origin of the bottom strip (RF 0 to 0.1).
System B Pretreat a 1.3- × 51-mm strip of chromatographic paper by soaking it for 1 minute in a 0.3 M carbonate-bicarbonate buffer, pH 9.0, prepared by dissolving 0.3 g of anhydrous sodium carbonate and 1.9 g of anhydrous sodium bicarbonate in 100 mL of water. Remove the paper strip, blot lightly with absorbent paper, and dry in an oven for about 45 minutes at 85. Proceed as directed for System A using the pretreated chromatographic paper and a developing solvent of methyl ethyl ketone. Free pertechnetate is located at the solvent front (top strip). The sum of the percentage of radioactivity at the origin in System A and the percentage of radioactivity at the solvent front in System B is not greater than 10.0%.
Biological distribution Inject between 75 MBq and 111 MBq (2 mCi and 3 mCi) of Injection, in a volume not exceeding 0.1 mL, into the caudal vein of each of three 25- to 40-g male albino mice. One hour after the injection, anesthetize and then decapitate the animals. Drain the blood of each separately into pre-weighed counting containers. Dissect the animals, and place the kidneys, liver, stomach (exclusive of duodenum), and gallbladder, and intestines, of each mouse into separate counting containers. Using a suitable counting assembly, determine the radioactivity of each container. Correct all radioactivity measurements for decay. Determine the percentage of radioactivity in the kidneys, liver, stomach, and gallbladder and intestines taken by the formula:
100(A / B)in which A is the radioactivity, in counts per minute, in the organ, and B is the total radioactivity, in counts per minute, injected. Determine the percentage of radioactivity in the blood taken by the formula:
[100(C / WS)0.07(WR)] / Bin which C is the radioactivity, in counts per minute, in the specimen of blood, WS is the weight, in g, of the blood specimen, 0.07 is the assumption that the total blood weight of the mouse is 7% of the total body weight, and WR is the weight, in g, of the mouse. Not less than 70% of the injected radioactivity is present in the gallbladder and intestines, not more than 10.0% of the injected radioactivity is present in the liver, not more than 10.0% of the injected radioactivity is present in the kidneys, not more than 3.0% of the injected radioactivity is present in the stomach, and not more than 3.0% of the injected radioactivity is present in the blood, in not less than two mice.
Other requirements It meets the requirements of the tests for Radionuclide identification, Radionuclidic purity, and Bacterial endotoxins under Sodium Pertechnetate Tc 99m Injection. It also meets the requirements under Injections 1, except that it may be distributed or dispensed prior to completion of the test for Sterility, the latter test being started on the date of preparation, and except that it is not subject to the recommendation on Volume in Container.
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USP32NF27 Page 3661