Development and Validation of an HPLC Method for Determination of Purity of Sn-ADAM, a Novel Precursor of Serotonin Transporter SPECT Imaging Agent I-123-ADAM

A reversed-phase high performance liquid chromatography (RP-H PLC) method for the purity assay of Sn-ADAM (2-((2-((Dimethylamino)methyl)phenyl)thio)-5-(tri-n-butyltin)-phenylamine) was developed and validated. Sn-ADAM is a precursor and free ligand of I-123-ADAM (I-123-2-([2-({dimethylamino}methyl)phenyl]thio)-5-iodophenylamine) that is a SPECT imaging agent for serotonin transporters (SERTs). The chromatographic separation for Sn-ADAM was achieved on a RP-18 column with an eluent consisting of methanol-acetonitrile-ammonium acetate (pH 7.0, 10 mM; 58.8 : 39.2 : 2, v/v/v). The absorbance at 220 nm against the concentration of Sn-ADAM was linear over the range of 9.9-317.8 ppm, with a correlation coefficient (r) of 0.99997. Method validation parameters, including specificity, linearity, precision, accuracy, LOD/LOQ, stability, robustness and suitability were evaluated, indicating the potential of this method in pharmaceutical quality control. Moreover, present results of precursor to product ion transitions of Sn-ADAM and I-127-ADAM by LC/ESI/MS/MS provided evidence for identification of fragmentation ions and proposition of the pathways of Sn-ADAM, I-127-ADAM and I-123-ADAM.