Ioflupane (¹²³I)

Clinical data
Trade names	Datscan, Striascan, Celsunax
Other names	Ioflupane (FPCIT); [I-123] N-ω-fluoropropyl- 2β-carbomethoxy- 3β-(4-iodophenyl) nortropane
AHFS/Drugs.com	Professional Drug Facts
License data	EU EMA: by ioflupane US DailyMed: Ioflupane
Routes of administration	Intravenous
ATC code	V09AB03 (WHO)
Legal status
Legal status	US: ℞-only[1][2] EU: Rx-only[3][4][5]
Pharmacokinetic data
Bioavailability	N/A
Excretion	Kidney and fecal
Identifiers
IUPAC name methyl (1R,2S,3S,5S)- 3-(4-iodophenyl)- 8-(3-fluoropropyl)- 8-azabicyclo[3.2.1]octane- 2-carboxylate
CAS Number	155798-07-5 N
PubChem CID	3086674
IUPHAR/BPS	7653
DrugBank	DB08824
ChemSpider	2343241
UNII	3MM99T8R5Q
KEGG	D10014 N
ChEBI	CHEBI:68855 N
ChEMBL	ChEMBL3989517 N
CompTox Dashboard (EPA)	DTXSID90935291
Chemical and physical data
Formula	C18H23FINO2
Molar mass	431.290 g·mol−1
3D model (JSmol)	Interactive image
SMILES COC(=O)[C@@H]1[C@H]2CCC(N2CCCF)C[C@@H]1C3=CC=C(C=C3)[123I]
InChI InChI=1S/C18H23FINO2/c1-23-18(22)17-15(12-3-5-13(20)6-4-12)11-14-7-8-16(17)21(14)10-2-9-19/h3-6,14-17H,2,7-11H2,1H3/t14-,15+,16+,17-/m0/s1/i20-4 Key:HXWLAJVUJSVENX-HFIFKADTSA-N
NY (what is this?)  (verify)

Ioflupane (¹²³I) is the international nonproprietary name (INN) of a cocaine analogue which is a neuro-imaging radiopharmaceutical drug, used in nuclear medicine for the diagnosis of Parkinson's disease and the differential diagnosis of Parkinson's disease over other disorders presenting similar symptoms. During the DaT scan procedure 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.^[6] The drug is sold under the brand name Datscan and is manufactured by GE Healthcare, formerly Amersham plc.

Pharmacology

Datscan is a solution of ioflupane (¹²³I) for injection into a living test subject.^[6]

The iodine introduced during manufacture is a radioactive isotope, iodine-123, and it is the gamma decay of this isotope that is detectable to a gamma camera. ¹²³I 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.^[6]

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 neurons 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^[6] and a scan should not be performed with less than 111 MBq.

Thyroid blocking via oral administration of 120 mg potassium iodide is recommended to minimize unnecessary excessive uptake of radioiodine.^[7] This is typically given 1–4 hours before the injection.^[6][8]

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.^[7][8]

Pharmacokinetics

Blood clearance of the radionuclide is rapid in healthy volunteers.^[9] Radioactivity was 4.5% of the injected amount 5 min after injection of ioflupane (¹²³I), falling to 2.2% at 30 min, 1.9% at 5 h, and declining to 1.3% at 24 h and 1.1% at 48 h after injection. Values were similar in both whole blood and plasma. Excretion was primarily renal.

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.^[6]

The radiation risks are reported as low. The committed effective dose for a single investigation on a 70 kg individual is 4.6 mSv.^[10] Pregnant patients should not undergo the test. It is not known if ¹²³I-ioflupane is secreted in breast milk however it is recommended that breastfeeding be interrupted for three days after administration.^[6]