ULTRA-TECHNEKOW FM Radionuclide generator Ref.[27727] Active ingredients: Technetium ⁹⁹ᵐTc pertechnetate

The pertechnetate ion has similar biological distribution to iodide and perchlorate ions, concentrating temporarily in salivary glands, choroid plexus, stomach (gastric mucosa) and in the thyroid gland, from which it is released unchanged. The pertechnetate ion also tends to concentrate in areas with increased vascularisation or with abnormal vascular permeability, particularly when pre-treatment with blocking agents inhibits uptake in glandular structures.^99mTc is selectively excluded from the cerebrospinal fluid.

Following intravenous administration, pertechnetate (^99mTc) is distributed throughout the vascular system from which it is cleared by three main mechanisms:

• Rapid removal, depending on the diffusion equilibrium with interstitial fluid
• Intermediate rate of removal, depending on the concentration of the pertechnetate in glandular tissues, mainly thyroid, salivary and gastric fundus glands which have an ionic pump mechanism
• Slow removal, by glomerular filtration by the kidneys, dependent on rate of urinary excretion.

Plasma clearance has a half-life of approximately 3 hours. Excretion during the first 24 hours following administration is mainly urinary (approximately 25%) with faecal excretion occurring over the next 48 hours. Approximately 50% of the administered activity is excreted within the first 50 hours. When selective uptake of pertechnetate (^99mTc) in glandular structures is inhibited by the pre-administration of blocking agents, excretion follows the same pathways but there is a higher rate of renal clearance. When pertechnetate (^99mTc) is administered in association with pre-treatment with reducing agents such as stannous/medronate which cause a “stannous loading” of red blood cells, up to approximately 95% of the administered activity is taken up by the red blood cells where it becomes bound within the cells. Any unbound pertechnetate (^99mTc) is cleared by the kidneys; radioactivity in the plasma normally constitutes less than 5% of the intravascular activity. The fate of the technetium-99m follows that of the labelled erythrocytes themselves and the activity is cleared very slowly. A small level of elution of activity from the circulating red cells is thought to occur.

There is no information on acute, subacute and chronic toxicity from single or repeated dose administration. The quantity of sodium pertechnetate (^99mTc) administered during clinical diagnostic procedures is very small and apart from allergic reactions, no other adverse reactions have been reported.

Reproductive Toxicity

Placental transfer of 99mTc from intravenously administered sodium pertechnetate (^99mTc) has been studied in mice. The pregnant uterus was found to contain as much as 60% of the injected ^99mTc when administered without perchlorate pre-administration. Studies performed on pregnant mice during gestation, gestation and lactation, and lactation alone showed changes in progeny which included weight reduction, hairlessness and sterility.