Synthesis of tritium labeled lipids

Recent achievements in the synthesis of lipids and pharmaceuticals labeled with tritium are considered. For introduction of the label into unsaturated compounds, liquid-phase methods were shown to be advantageous over gas-pha se ones. Thus, tritiation or selective tritiation of compounds with multipl e bonds may result in preparations with a specific radioactivity of 1-2 PBq /mol per one reduced bond, whereas isotope exchange with tritium gas may on ly provide preparations with a specific radioactivity of approximately 0.1 PBq/mol. Solid phase methods of labeling at temperatures above 100 degrees C are the best for saturated compounds, Isotope exchange with tritium water or chemical methods (when a high molar radioactivity of up to several PBq/ mol is necessary) may be used in the case of compounds unstable when treate d with gaseous tritium.