Analysis of 99mTc-labeled radiopharmaceuticals by high-performance liquid chromatography

High-performance liquid chromatography (HPLC) equiped with on line radiometric and optical detectors (i.e. radio-HPLC) have been applied to the radiochemical analysis of commonly-used 99mTc-radio pharma ceuticals with a view point to check the radiochemical purities of the compounds. Chromatographic conditions were determined by examination of the types of column, mobile phase and pH. An aqueous size-exclusion (Shim-pack Diol-300) and reversed-phase column (Zorbax-ODS) were found to be suitable for 99mTc-HSA and the other 99mTc-agents, respectively. The analysis of low molecular weight 99mTc-agents (e.g. 99mTc-DTPA, 99mTc-DMSA, 99mTc-pyrophosphate, 99mTc-phytic acid, 99mTc-MDS, 99mTc-HMDP) were done by reversed-phaseion pairing chromatography using a optimized mobile phase consisted on a mixture of 50 mM phosphate buffer (pH 7.0) and 2 mM TBA (tetra nbutyl) ammonium hydroxide) in 30 % methanol. The mobile phases for analysis of medium molecular weight 99mTc-HSA were consisted of a mixture of 50 mM phosphate buffer (ph 7.0) in 30 % methanol, and a mixtures of 1 % SDS (sodium dodecyl sulfonate) in Tris buffer (pH. 7.0), respectively. It was apparent from the radio-chromatograms obtained from these chromatographic conditions, that impurity of 99mTcO4 was observed in 99mTc-pyrophosphate, 99mTc-phytic acid, 99mTc-MDP, 99mTc-HMDP, and impurities of 99mTc-labeled species and 99mTcO4, were observed in 99mTc-HIDA, 99mTc-HIDA, 99mTc-HSA. The radiochemical impurities of the 99mTc-radiopharmaceuticals were ranged between 90 and 100 %. From these results, radio-HPLC has been shown to be suitable method for analysis of 99mTc-radiopharmaceuticals, with rapidity and excellent precision. (author)