AZEDRA Solution for injection Ref.[10319] Active ingredients: Iobenguane ¹³¹I

AZEDRA (iobenguane I 131) injection, for intravenous use, is a radioactive therapeutic agent. The drug substance iobenguane I 131 is a substituted benzylguanidine with I 131 in the meta position of the benzene ring.

Iobenguane I 131 is described as I 131 meta-iodobenzylguanidine. The molecular weight is 279.1 Daltons and the structural formula is as follows:

AZEDRA (iobenguane I 131) 555 MBq/mL (15 mCi/mL) injection is a sterile, clear, colorless to pale yellow solution. Each single-dose vial contains iobenguane (0.006 mg/mL), sodium ascorbate (58 mg/mL) and sodium gentisate (23 mg/mL) in Water for Injection, USP. The pH range of the solution is 4.5 to 5.5, with specific activity of ~2,500 mCi/mg (92,500 MBq/mg).

11.1 Physical Characteristics

I 131 decays with beta and gamma emissions with a physical half-life of 8.021 days. The principal beta emission has a mean energy of 191.6 keV, and the principal gamma emission has energy of 364.5 keV.

11.2 External Radiation

The specific gamma ray constant for I 131 is 2.2 R/mCi hour at 1 cm. A 2.55 cm thickness of Pb will attenuate the radiation emitted by a factor of about 1,000.

Table 6 summarizes radioactive decay properties of I 131.

Table 6. Physical Decay Chart: Iodine I 131: Half-Life = 8.021 Days:

^a Calibration day.