carboplatin

Other names: Paraplatin®

C₆H₁₂N₂O₄Pt

48/50 rare

Carboplatin represents a second-generation platinum-based antineoplastic agent developed to overcome the severe toxicities associated with cisplatin while maintaining therapeutic efficacy. Approved by the FDA in 1989, this compound features the same square-planar platinum(II) center coordinated to two ammonia molecules as cisplatin, but replaces the reactive chloride ligands with a bidentate dicarboxylate derived from cyclobutane-1,1-dicarboxylic acid. This structural modification creates a more stable leaving group, significantly slowing the aquation rate that activates platinum drugs. The resulting slower kinetics dramatically reduces nephrotoxicity and neurotoxicity while allowing higher doses and less aggressive hydration protocols compared to cisplatin. Like its predecessor, carboplatin's mechanism involves the formation of intrastrand DNA crosslinks, primarily between adjacent guanine bases, distorting the double helix and disproportionately triggering apoptotic pathways in cancer cells. Its distinctive cyclobutane ring structure with a quaternary carbon provides the ideal geometry for forming the stable chelate around platinum. Carboplatin appears as a white crystalline powder and is typically administered intravenously. This compound exemplifies the rational drug design approach in medicinal inorganic chemistry, demonstrating how structural modifications of a metal complex can tune pharmacokinetic properties while preserving the essential DNA-targeting mechanism that makes platinum drugs effective against various malignancies.