ISSN:
1588-2780
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract L-3-[123I] iodo-α-methyltyrosine has been reported to have a high affinity for a transport system in the blood-brain-barrier (BBB). Synthesis of L-3-[123/131I] iodo-α-methyltyrosine was performed by direct electrophilic iodination starting with no carrier added (n.c.a)131I or123I in the presence of oxidizing agent. Different oxidizing agents have been tested and the different factors affecting the radiochemical yield of L-3-[123I] iodo-α-methyltyrosine have been investigated. A method of pharmaceutical preparation of L-3-[123I] iodo-α-methyltyrosine ready for medical applications has been described. Among the oxidizing agents tested, iodogen in phosphate buffer at pH 7 seems to be the best which gives high radiochemical yield (85%) within 5 minute reaction time at room temperature in the presence of small amount KI (0.001 μg) as a carrier. The radioactive impurities and side chlorinated by-product which have been found in case of iodination by chloramine-T (CAT), KIO3 and H2O2 methods disappear in case of iodogen method. The labelled product was separated and purified by radio high pressure liquid chromatography (HPLC) using methanol∶water∶acetic acid (20∶80∶1) as eluant at a flow rate 1.0 ml/min. According to the signals of the detectors the fractions of L-3-[123I] iodo-α-methyltyrosine were collected, evaporated to complete dryness and the residue dissolved in isotonic phosphate buffer pH 7.4. The product was sterilized by passing through 0.22 μm millipore filter and the radiopharmaceutical was now ready for nuclear medical application.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02038048
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