Fast and efficient tritium labelling of the nonsteroidal anti‐inflammatory drugs naproxen, tolmetin, and zomepirac

Fast and efficient tritium labelling of the nonsteroidal anti-inflammatory drugs naproxen, tolmetin and zomepirac is reported. Naproxen along with its (R)-enantiomer were labelled by catalytic tritium–halogen exchange of the corresponding 5-bromo derivatives providing [3H]naproxen with a specific activity of 25.4 Ci/mmol. Tolmetin and zomepirac were labelled by the hydrogen isotope exchange reaction using Crabtree's catalyst. This provided [3H]tolmetin and [3H]zomepirac with specific activities of 80.8 and 64.3 Ci/mmol, respectively. All compounds were obtained in high radiochemical purity (>98%). Copyright © 2005 John Wiley & Sons, Ltd.