Ioflupane (123I)

Ioflupane (¹²³I)

Systematic (IUPAC) name
methyl (1R,2S,3S,5S)- 3-(4-iodophenyl)- 8-(3-fluoropropyl)- 8-azabicyclo[3.2.1]octane- 2-carboxylate
Clinical data
Licence data	EMA:Link
Pregnancy cat.	Contraindicated
Legal status	℞ Prescription only
Routes	Intravenous
Pharmacokinetic data
Bioavailability	N/A
Excretion	Renal and fecal
Identifiers
CAS number	155797-99-2
ATC code	V09AB03
PubChem	CID 3086674
Synonyms	Ioflupane (FPCIT); [I-123] N-ω-fluoropropyl- 2β-carbomethoxy- 3β-(4-iodophenyl) nortropane
Chemical data
Formula	C18H23FINO2
Mol. mass	427.285 g/mol
SMILES	eMolecules & PubChem
Y(what is this?)  (123I) (verify)

Midbrain slice of a SPECT DaTSCAN image showing normal striatal morphology

Ioflupane (¹²³I) is the International Nonproprietary Name of a phenyltropane compound which is a neuro-imaging radiopharmaceutical drug, used by nuclear medicine physicians for the diagnosis of Parkinson's disease and the differential diagnosis of Parkinson's disease over other disorders presenting similar symptoms. It is injected into a patient and viewed with a gamma camera in order to acquire SPECT images of the brain with particular respect to the striatum, a subcortical region of the basal ganglia.^[1] The drug is sold under the tradename DaTSCAN and is manufactured by GE Healthcare, formerly Amersham plc. It is not marketed outside of Europe and the United States.

Pharmacology

DaTSCAN is a solution of ioflupane (¹²³I) for injection into a living test subject.

The iodine introduced during manufacture is a radioactive isotope, I-123, and it is the properties of this isotope that makes the solution visible to a gamma camera. I-123 has a half life of approximately 13 hours and a gamma photon energy of 159 keV making it an appropriate radionuclide for medical imaging. The solution also contains 5% ethanol to aid solubility and is supplied sterile since it is intended for intravenous use.

Ioflupane has a high binding affinity for presynaptic dopamine transporters (DAT) in the brains of mammals, in particular the striatal region of the brain. A feature of Parkinson's disease is a marked reduction in dopaminergic neurones in the striatal region. By introducing an agent that binds to the dopamine transporters a quantitative measure and spatial distribution of the transporters can be obtained.

Method of administration

The DaTSCAN solution is supplied ready to inject with a certificate stating the calibration activity and time. The nominal injection activity is 185 MBq^[1] and a scan should not be performed with less than 111MBq.

Thyroid blocking via oral administration of 120 mg potassium iodide is recommended to minimise unnecessary excessive uptake of radioiodine. One dose is given 2 hours before the injection and a further dose 24 hours later.

The most convenient way to administer the IV dose is via a peripheral intravenous cannula. The scan is carried out 3 to 6 hours post injection.

Risks

Common side effects of ioflupane (¹²³I) are headache, vertigo, increased appetite and formication. Less than 1% of patients experience pain at the injection site.^[1]

The radiation risks are reported as low. The committed effective dose for a single investigation on a 70 kg individual is 4.35 mSv.^[2] Pregnant patients should not undergo the test and breast feeding patients must cease since I-123 is secreted in breast milk.

See also

• List of cocaine analogues

References

1. ^ ^{a b c} GE Healthcare Ltd. DaTSCAN - Prescribing information
2. ^ Administration of Radioactive Substances Advisory Committee (2006). Notes for Guidance on the Clinical Administration of Radiopharmaceuticals and Use of Sealed Radioactive Sources.