Technetium Tc 99m Lidofenin Injection
» Technetium Tc 99m Lidofenin Injection is a sterile, clear, colorless solution of lidofenin complexed to radioactive technetium (99mTc) in the form of a chelate. It is suitable for intravenous injection and may contain buffers. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of 99mTc as the lidofenin chelate expressed in megabecquerels (millicuries) per mL at the time indicated in the labeling. Other chemical forms of radioactivity do not exceed 10.0 percent of the total radioactivity.
Packaging and storage— Preserve in single-dose or multiple-dose containers at a temperature between 2 and 8.
Labeling— Label it to include the following, in addition to the information specified for Labeling under Injections 1: the time and date of calibration; the amount of 99mTc as labeled lidofenin expressed as total megabecquerels (millicuries) per mL at the time of calibration; the expiration date and time; the storage temperature and the statement “Caution—Radioactive 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.
USP Reference standards 11
USP Endotoxin RS
Bacterial endotoxins 85 The limit of endotoxin content is not more than 175/V Endotoxin Units per mL of Injection, in which V is the maximum recommended total dose, in mL, at the expiration date or time.
pH 791: between 3.5 and 5.0.
Radiochemical purity— Not more than 10.0 percent of the total radioactivity is found as free 99mTc pertechnetate (TcO4), hydrolysed 99mTc and 99mTc technetium tin colloid. The presence of these impurities is determined as follows:
Unbound pertechnetate— Apply a measured volume of Injection such that it provides a count rate of about 50,000 counts per minute, about 15 mm from the end of a 100-mm × 10-mm strip of silicic-acid impregnated fiberglass paper. Dry the spot using a gentle stream of nitrogen and develop immediately using a nitrogen-purged saturated solution of sodium chloride until the solvent front has moved four-fifths of the length of the strip. Determine the distribution of radioactivity on the strip by the use of a strip-scanner or other suitable method. Unbound pertechnetate is found at an RF value between 0.5 and 1.0. Technetium Lidofenin, hydrolysed and colloidal 99mTc technetium remain at the origin.
Hydrolysed and reduced 99mTc technetium—Apply a measured volume of Injection such that it provides a count rate of about 50,000 counts per minute, about 15 mm from the end of a 100-mm × 10-mm strip of silica gel impregnated fiberglass paper. Dry the spot using a gentle stream of nitrogen and develop immediately using a solution consisting of a mixture of acetonitrile and water (3:1) until the solvent front has moved four-fifths of the length of the strip. Determine the distribution of radioactivity on the strip by the use of a strip-scanner or other suitable method. Unbound pertechnetate and Technetium Lidofenin are found at an RF value between 0.5 and 1.0. Hydrolysed and colloidal 99mTc technetium remain at the origin.
Biological distribution— Inject intravenously between 0.75 and 1.85 MBq (20 µCi and 50 µCi) of the Injection into the lateral tail vein of each of three 20-g to 25-g mice. Maintain the injected animals in clean cages with free access to food and water for 1 hour. Sacrifice the animals by carbon dioxide or ether asphyxiation and withdraw approximately 1 mL of blood. Dissect the animals and remove the liver, gallbladder, and small and large intestines. Remove the tail. Weigh the blood sample. Place the blood sample, organs, and tail in separate counting tubes and determine the activity in each. Correct for decay to the time of injection. Determine the percentage of radioactivity in each organ and blood using the formula:
100B/A
in which B is the net radioactivity in the organ, and A is the total radioactivity injected. Assume that the total blood weight is 7.0% of total body weight. If more than 5% of the injected dose is found in the tail, disregard the results from that animal. If more than one animal is rejected on this basis, repeat the entire test with three more animals. Not less than 65% of the total radioactivity is found in the gallbladder and intestines, not more than 10% of the total radioactivity is found in the liver and not more than 2% of the total radioactivity is found in the blood in two out of three mice.
Other requirements— It meets the requirements of the tests for Radionuclide identification and Radionuclide purity under Sodium Pertechnetate Tc 99m Injection. It 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 day of manufacture, and except that it is not subject to the recommendation on Volume in Container.
Assay for radioactivity 821 Using a suitable counting assembly (see Selection of a Counting Assembly), determine the radioactivity in MBq(µCi) per mL, of Injection by use of a calibrated system.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ravi Ravichandran, Ph.D.
Principal Scientific Liaison
1-301-816-8330
(SM42010) Monographs - Small Molecules 4
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
85 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
USP35–NF30 Page 4766