VOLUMEX Solution for injection Ref.[10323] Active ingredients: Iodine ¹³¹I human albumin

Volumex (Iodinated I 131 Albumin Injection) is a diagnostic radiopharmaceutical containing iodinated I 131 albumin for intravenous use. Each mL of sterile, nonpyrogenic, aqueous, colorless to very pale yellow solution provides approximately 10 mg protein (albumin human), 16 mg dibasic sodium phosphate, 1.6 mg monobasic sodium phosphate, not more, than 0.4 mg guanidine hydrochloride, sodium chloride for isotonicity, and 9 mg benzyl alcohol as a preservative. The stabilizer acetyltryptophanate and sodium caprylate have a concentration of less than 0.0089M. The pH has been adjusted to 7.2-7.8 with sodium hydroxide or hydrochloric acid.

Volumex was prepared from blood that was nonreactive when tested for hepatitis B surface antigen (HB_sAg). The structure of the complex is unknown.

Physical Characteristics

Iodine 131 decays by beta and gamma emissions with a physical half-life of 8.08 days.¹

Photons that are useful for detection and imaging studies are listed in Table 1.

Table 1. Principal Radiation Emission Data:

¹ Evaluated Nuclear Structure Data File of the Oak ridge Nuclear Data Project DOE (1985).

External Radiation

The specific gamma ray constant for iodine 131 is 2.2R/hour-millicurie at 1 cm. The first half-value layer is 0.24 cm lead (Pb). A range of values for the relative attenuation of the radiation emitted by this radionuclide that result from interposition of various thicknesses of Pb is shown in Table 2. To facilitate control of the radiation exposure from this radionuclide, the use of a 2.55 cm thickness of Pb will attenuate the radiation emitted by a factor of about 1,000.

Table 2. Radiation Attenuation by Lead Shielding:

To correct for physical decay of iodine 131, the fractions that remain at selected intervals before and after the time of calibration are shown in Table 3.

Table 3. Physical Decay Chart: I-131 half-life 8.08 days:

* Calibration time