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Amyvid

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Amyvid

Amyvid
(florbetapir F 18) Injection

DRUG DESCRIPTION

Amyvid contains florbetapir F 18, a molecular imaging agent that binds to β-amyloid aggregates, and is intended for use with PET imaging of the brain. Chemically, florbetapir F 18 is described as (E)-4-(2-(6-(2-(2-(2[18F] fluoroethoxy)ethoxy) ethoxy)pyridine-3-yl)vinyl)-N-methylbenzamine. The molecular weight is 359 and the structural formula is:

Amyvid (Florbetapir F 18 Injection) Structural Formula Illustration

Amyvid is a sterile, non-pyrogenic radioactive diagnostic agent for intravenous injection. The clear, colorless solution is supplied ready to use and each milliliter contains 0.1 to 19 micrograms of florbetapir and 500 -1900 MBq (13.5 -51 mCi) florbetapir F 18 at EOS, 4.5 mg sodium ascorbate USP and 0.1 mL dehydrated alcohol USP in 0.9% sodium chloride injection USP. The pH of the solution is between 5.5 and 7.5.

Physical Characteristics

Amyvid is radiolabeled with [18F] fluorine (F 18) that decays by positron (β+) emission to O 18 and has a half-life of 109.77 minutes. The principal photons useful for diagnostic imaging are the coincident pair of 511 keV gamma photons, resulting from the interaction of the emitted positron with an electron (Table 3).

Table 3: Principal Radiation Produced from Decay of Fluorine 18

Radiation Energy Level (keV) Abundance (%)
Positron 249.8 96.9
Gamma 511 193.5

External Radiation

The point source air-kerma coefficienta for F-18 is 3.74E -17 Gy m²/(Bq s); this coefficient was formerly defined as the specific gamma-ray constant of 5.7 R/hr/mCi at 1 cm. The first half-value thickness of lead (Pb) for F 18 gamma rays is approximately 6 mmb. The relative reduction of radiation emitted by F-18 that results from various thicknesses of lead shielding is shown in Table 4. The use of ~8 cm of Pb will decrease the radiation transmission (i.e., exposure) by a factor of about 10,000.

Table 4: Radiation Attenuation of 511 keV Gamma Rays by Lead Shielding

Shield Thickness cm of lead (Pb) Coefficient of Attenuation
0.6 0.5
2 0.1
4 0.01
6 0.001
8 0.0001
 

aEckerman KF and A Endo. MIRD: Radionuclide Data and Decay Schemes, 2nd Edition, 2008.
bDerived from data in NCRP Report No. 49. 1998, Appendix C

Last reviewed on RxList: 1/23/2014
This monograph has been modified to include the generic and brand name in many instances.

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Report Problems to the Food and Drug Administration

 

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


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