Ioflupane (123I)

Ioflupane (123I) is the International Nonproprietary Name 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. 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.[2] The drug is sold under the tradename DaTSCAN and is manufactured by GE Healthcare, formerly Amersham plc. It is not marketed outside Europe and the United States.[1]

SPECT DaTSCAN showing normal Ioflupane (123I) uptake in the striatum.
Ioflupane (123I)
Clinical data
Other namesIoflupane (FPCIT);
[I-123] N-ω-fluoropropyl- 2β-carbomethoxy- 3β-(4-iodophenyl) nortropane
License data
Pregnancy
category
  • X
Routes of
administration		Intravenous
ATC code
Legal status
Legal status
  • US: Rx-only[1]
Pharmacokinetic data
BioavailabilityN/A
ExcretionRenal and fecal
Identifiers
CAS Number
PubChem CID
IUPHAR/BPS
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
Chemical and physical data
FormulaC18H23FINO2
Molar mass427.285 g/mol g·mol−1
3D model (JSmol)
 NY (what is this?)  (verify)

Pharmacology

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

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.

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[2] 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.[3] This is typically given 1-4 hours before the injection.[2][4]

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.[3][4]

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.[2]

The radiation risks are reported as low. The committed effective dose for a single investigation on a 70 kg individual is 4.6 mSv.[5] 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 is interrupted for three days after administration.[2]

See also

References
  1. "Removal of [123I]Ioflupane From Schedule II of the Controlled Substances Act". DEA Diversion Control Division. Archived from the original on 13 May 2017. Retrieved 2016-02-09.
  2. "DaTSCAN Summary of Product Characteristics" (PDF). European Medicines Agency. GE Healthcare. 25 July 2019.
  3. Darcourt, Jacques; Booij, Jan; Tatsch, Klaus; Varrone, Andrea; Vander Borght, Thierry; Kapucu, Özlem L.; Någren, Kjell; Nobili, Flavio; Walker, Zuzana; Van Laere, Koen (17 October 2009). "EANM procedure guidelines for brain neurotransmission SPECT using 123I-labelled dopamine transporter ligands, version 2". European Journal of Nuclear Medicine and Molecular Imaging. 37 (2): 443–450. doi:10.1007/s00259-009-1267-x. PMID 19838702.
  4. Djang, D. S. W.; Janssen, M. J. R.; Bohnen, N.; Booij, J.; Henderson, T. A.; Herholz, K.; Minoshima, S.; Rowe, C. C.; Sabri, O.; Seibyl, J.; Van Berckel, B. N. M.; Wanner, M. (8 December 2011). "SNM Practice Guideline for Dopamine Transporter Imaging with 123I-Ioflupane SPECT 1.0". Journal of Nuclear Medicine. 53 (1): 154–163. doi:10.2967/jnumed.111.100784. PMID 22159160.
  5. "Notes for Guidance on the Clinical Administration of Radiopharmaceuticals and Use of Sealed Radioactive Sources". ARSAC. Public Health England. 13 February 2019.
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