Chemical reactivity of cisplatin bound to human plasma proteins

Human plasma was incubated with cisplatin over 24 h. Ultrafilterable platinum and platinum reactive with DDTC were determined at regular time intervals during incubation. At each time point more platinum reacted with sodium N,N1-diethyldithiocarbamate (DDTC) than was available as ultrafilterable platinum. At 24 h 70% of total platinum (10% ultrafiltrable platinum and 60% protein-bound platinum) reacted with DDTC. This means that cisplatin bound to plasma proteins can--at least in part--still react with strong nucleophiles.