Quantitative imaging of platinum-based antitumor complexes in bone tissue samples using LA-ICP-MS.

There is a need for effective medication against bone metastases because todays drugs are not able to penetrate the bone and reach the affected areas. To analyze if current or future platinum-containing drugs are able to achieve this, a quantitative imaging method is urgently needed. In this study, the platinum distribution in thin sections of mice tibia was determined using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in a spatially resolved manner. The hard bone tissue visible in microscopic images and signals found for calcium and phosphorous recorded via LA-ICP-MS and micro X-ray fluorescence spectroscopy (μXRF) correlate well. Furthermore, the platinum concentration was quantified using polymer-based matrix-matched standards. A limit of detection of 6 μg/g and a linearity of almost three decades could be achieved. Concentrations surpassing 300 μg/g could be found in the tibia samples. The method presented herein is a powerful approach for the visualization and quantification of platinum. As such, this method is a valuable tool to unravel the mechanism of delivery and optimize the therapeutic potency of platinum-containing drugs targeting bone diseases like bone metastases.