[en] Aim: Matrix metalloproteinases (MMPs) are a family of at least 18 secreted and membrane-bound zinc endopeptidases. Collectively they function in the degradation of extracellular matrix proteins and play an important role in both normal and pathological tissue remodelling. Increased MMP activity is detected in a wide range of cancers and seems to be correlated to their invasive and metastatic potential. MMPs thus seem an attractive target for both diagnostic (SPECT tracer) and therapeutic purposes. Therefore, we synthesised a ¹²³I-labelled MMP 2 inhibitor and evaluated it in vitro. Materials and methods: The ¹²³I-labelled compound was synthesised by a Cu-assisted nucleophilic non-isotopic exchange starting from Br-BSP. After reaction, the mixture was purified by HPLC. IC₅₀ values were obtained by in vitro enzyme assays. A 1:1 mix between non-radiolabelled inhibitor (concentration range: 300 nM - 0.05 nM) and enzymes (MMP2, cMT1-MMP, cMT3-MMP) was incubated for 15 minutes at 37⁰C. The fluorescent substrate (Mca-Pro-Leu-Gly-Leu-Dap(Dnp)-Ala-Arg-NH2) was added and the increase of fluorescence versus time, due to the hydrolysis of substrate, was measured (GEMINI-XS, λ_exc = 328 nm and λ_em = 393nm). Initial velocities were calculated for different concentrations of inhibitor and the IC₅₀ values were then determined. Results: Radiochemical yield was 30% ±3%. Radiochemical purity was >95%. IC₅₀ values for inhibition of MMP2, cMT3-MMP and cMT1-MMP were 0.5 nM, 7.1 nM and 16.9 nM respectively. Conclusion: ¹²³I-BSP was synthesised with 30% ±3% yield. After HPLC the radiochemical purity was >95%. In vitro enzyme assays of I-BSP showed an inhibition of MMP2, cMT3-MMP and cMT1-MMP in the low nM range (0.5 nM, 7.1 nM and 16.9 nM respectively). In vivo studies (biodistribution, metabolizing) in mice will be performed in the near future