1-Minute quality control tests for positron emission tomography radiopharmaceuticals

An ultra-fast, sensitive and versatile radio-liquid chromatographic (LC) procedure was developed and validated for quality control (QC) tests of PET radiopharmaceuticals. For a wide variety of radio-probes, the usual LC conditions were used: (1) column: Waters XBridge RP18 (50 mm × 3.0 mm ID, 2.5 μm), (2) mobile phase: a mixture of three modifiers (90% CH3CN, ammonium phosphate at pH 2.1 and pH 9.3), and (3) detection: UV absorption and NaI(Tl) scintillation. The introduction of a short column packed with small particles of 2.5 μm allowed excellent separation of target analytes within a very short run time of 1 min; only a 3% decline of radioactivity was observed during QC analysis of 11C-labelled pharmaceuticals. Combining ammonium-phosphate buffer as the mobile-phase component and low-wavelength UV detection led to an improvement in the applicability and sensitivity. All 34 pharmaceuticals investigated could be successfully applied to determine the specific radioactivity, radiochemical and chemical purity with 10-times better sensitivity than traditional LC. We could analyze different pharmaceuticals in a short period since this system utilized a common column and mobile phase. The proposed procedure fulfils the requirements for routine QC tests in terms of rapidity, sensitivity, simplicity and applicability.