INDIUM IN-111 OXYQUINOLINE Solution for injection Ref.[27549] Active ingredients: Indium ¹¹¹In oxyquinoline

Indium In-111 oxyquinoline (oxine) is a diagnostic radiopharmaceutical intended for radiolabeling autologous leukocytes. It is supplied as a sterile, non-pyrogenic, isotonic aqueous solution with a pH range of 6.5 to 7.5. Each mL of the solution contains 37 MBq, 1 mCi of indium In-111 [no carrier added, >1.85 GBq/µg indium (>50 mCi/µg indium)] at calibration time, 50 µg oxyquinoline, 100 µg polysorbate 80, and 6 mg of HEPES (N-2-hydroxyethyl-piperazine-N'-2-ethane sulfonic acid) buffer in 0.75% sodium chloride solution. The drug is intended for single use only and contains no bacteriostatic agent. The radionuclidic impurity limit for indium 114m is not greater than 37 kBq, 1 µCi of indium 114m per 37 MBq, 1 mCi of indium In-111 at the time of calibration. The radionuclidic composition at expiration time is not less than 99.75% of indium In-111 and not more than 0.25% of indium In 114m/114.

Chemical name: Indium In-111 Oxyquinoline.

The precise structure of the indium In-111 oxyquinoline complex is unknown at this time. The empirical formula is (C₉H₆NO)₃ In-111.

Physical characteristics

Indium In-111 decays by electron capture with a physical half-life of 67.2 hours (2.8 days). The energies of the photons that are useful for detection and imaging studies are listed in Table 1.

Table 1. Principal Radiation Emission Data*:

^* Kocher, David C., "Radioactive Decay Data

External radiation

The exposure rate constant for 37 MBq, 1 mCi indium In-111 is 8.3 × 10^-4 C/kg/h (3.21 R/h) at 1 cm. The first half value thickness of lead (Pb) for indium In-111 is 0.023 cm. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from the interposition of various thicknesses of Pb is shown in Table 2. For example, the use of 0.834 cm of lead will decrease the external radiation exposure by a factor of about 1,000.

Table 2. Radiation Attenuation by Lead Shielding*:

These estimates of attenuation do not take into consideration the presence of longer-lived contaminants with higher energy photons, namely indium In 114m/114.

To allow correction for physical decay of indium In-111, the fractions that remain at selected intervals before and after the time of calibration are shown in Table 3.

Table 3. Physical Decay Chart for Indium In-111, Half-life 67.2 hours:

^* Calibration Time