title: Preparation and biological evaluation of (99m)Tc-ropinirole as a novel radiopharmaceutical for brain imaging.
abstract: Noninvasive brain imaging is a process that allows scientists and physicians to view and monitor the areas of the brain. The aim of this study was to formulate a novel radiopharmaceutical for the detection of brain disorders at early stages in susceptible patients. (99m) Tc-ropinirole was prepared by the direct complexation of ropinirole with technetium-99m. The results showed that the radiochemical yield (99m) Tc-ropinirole was 92 ± 2.87% and the radiochemical yield was evaluated by paper chromatography and HPLC. In vitro studies showed that the formed complex was stable for up to 6 h. In vivo uptake of (99m) Tc-ropinirole in the brain was 4.87 ± 0.15% injected dose/g organ at 30 min post-injection, which cleared from the brain with time till it reaches 2.3% at 2 h post-injection indicating that the brain uptake of (99m) Tc-ropinirole is higher than that of the commercially available (99m) Tc-HMPAO, which is 2.25% at 30 min. Pre-dosing mice with cold ropinirole reduced the brain uptake to 0.26 ± 0.01% injected dose/g organ, so this confirms the high specificity and selectivity of this radiotracer for the assessment of the dopamine receptors.
authors.affiliation: Hot Labs Center, Egyptian Atomic Energy Authority, Cairo, Egypt.
authors.forename: M A
authors.initials: MA
authors.lastname: Motaleb
authors.affiliation: Hot Labs Center, Egyptian Atomic Energy Authority, Cairo, Egypt.
authors.forename: I T
authors.initials: IT
authors.lastname: Ibrahem
authors.affiliation: Hot Labs Center, Egyptian Atomic Energy Authority, Cairo, Egypt.
authors.forename: V R
authors.initials: VR
authors.lastname: Ayoub
authors.affiliation: Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: A S
authors.initials: AS
authors.lastname: Geneidi
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D007553:Isotope Labeling; D007700:Kinetics; D051379:Mice; D011854:Radiochemistry; D019275:Radiopharmaceuticals / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics; D011954:Receptors, Dopamine / Q000378:metabolism; D013379:Substrate Specificity; D013667:Technetium / Q000737:chemistry*; D017971:Tin Compounds / Q000737:chemistry; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D007211:Indoles; D019275:Radiopharmaceuticals; D011954:Receptors, Dopamine; D017971:Tin Compounds; C046649:ropinirole; C023599:stannous chloride; D013667:Technetium
keywords: 99mTc-ropinirole; brain imaging; receptor selectivity; stannous chloride