A Fast Photoisomerization Method for the Preparation of Tritium-Labeled 9-cis-Retinoic Acid of High Specific Activity

✍ Scribed by H.J. Cahnmann

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 443 KB
• Volume: 227
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1006/abio.1995.1251

✦ Synopsis

A method is described by which tritium-labeled alltrans retinoic acid of high specific activity (up to (\sim 51) (\mathrm{Ci} / \mathrm{mmol}) corresponding to (85 %) of theoretical) is converted photolytically within a fraction of a second to a mixture of retinoic acid stereoisomers. One of these isomers, 9-cis-retinoic acid, was obtained in high radiochemical purity by reverse-phase HPLC of the stereoisomer mixture. This fast photolysis was obtained by using a high-pressure 100-W mercury lamp operated at (86 \pm \mathbf{2}) W. A copper sulfate solution was used as a light filter to eliminate short-wave ultraviolet radiation as well as much of the infrared radiation. The geometry of the experimental set-up allowed a maximal amount of the light output of the lamp to reach the retinoic acid solution. Reverse-phase HPLC of the photolytically generated retinoic acid stereoisomer mixture provided pure 9-cis-retinoic acid in (4.5 %) yield after irradiation for (0.6 \mathrm{~s}). A steady-state equilibrium of retinoic acid stereoisomers was reached when the irradiation time was extended to a total of 4-6 (\mathrm{s}(10-11 %) yield of 9 -cis retinoic acid). c 1995 Academic Press, Inc.