Radiolabelling And Bio Distribution Studies For Radio Tracer S-(-)-¹²³I BZM Utilized For Neurobrain Disease Diagnosis

The radiolabeling of S-(-)-BZM enantiomer with radio iodine ¹²³I is performed in this study with 78 % labeling yield and radio chemical purity RCP > 95 % at gentle reaction conditions using a new method to achieve the labeling process depending on Iodogen compound as a strong oxidant which converts negative ion ^-I in a mild aquatic medium at the room temperature degree during a short time to positive ion ⁺I which owns a high efficiency for electrophilic substitution with S-(-) -BZM aromatics hydrogen then simple and speed techniques are for purifying procedures so ready-made used filters are used to remove undesirable organic and radio impurities, whereas RCP were detected using Instant thin layer chromatography in presence of gamma detector to illustrate the radio spot, on the other hand the biological part of this study was accomplished utilizing from more than 15 Wistar han laboratory rats, so that a comprehensive kinetic study was carried out for radio tracer S-(-)- ¹²³I- BZM uptakes from important organs and regions inside rats body especially at the brain region, and as prospective S-(-)- ¹²³I- BZM high showed ability in brain blood barrier penetration with brain uptake ratio exceeded 2% , 1.6 % and 0.6 % from total injected dose after 0.5, 1 and 2 hours post injection respectively, in general S-(-)- ¹²³I- BZM tracer showed decreasing uptakes in the major studied parts except uptake increasing at intestine and urine du to excretion operation, but the most important part of this worke was concentrating on tracer uptake profile in brain regions which own a variable densities of dopamine D2 receptor, therefor brain kinetic study was performed and four relative regions were isolated: Striatum as high density region of dopamine receptor, Frontal cortex and Hippocampus as low density regions of dopamine receptor, also cerebellum region was segregated which is well known as a poor region with the most kinds of brain receptors so it used usually as comparative region at the majority of brain studies, S-(-)- ¹²³I- BZM showed high selectivity binding with dopamine D2 receptors and practically the ratio between the brains region uptake and cerebellums uptake was depended to assess the selective binding effectivity with D2 receptors, so 30 minutes after injection the specific binding ratio was close from 2 for three brain regions which confirms cerebellum is a poor region with D2 receptors in contrast with Striatum, Frontal that cortex and Hippocampus regions, but after 1 hour from the injection specific binding ratio was doubled and so that the selective binding effectivity with D2 receptors for Striatum region, whereas the ratio was still close from 2 for Frontal cortex and Hippocampus regions, yet after 2 hours from the injection the ratio becomes 7.4 for Striatum and still almost static around 2 for another regions, therefore radiography is usually done between the first and the second hour post injection with S-(-)- ¹²³I- BZM tracer, consequently the results emphasize on S-(-)- ¹²³I- BZM effectivity as a one of an important compounds which are used for a different Neuropsychiatric disorders investigation. (author).