Carmustine

Carmustine is a nitrosourea alkylating agent. After decomposition in the body, carmustine releases a chloroethyl carbonium ion, a highly reactive intermediate that forms covalent bonds with DNA bases, especially at the N7 or O6 positions of guanine, thereby interfering with DNA replication and transcription, suppressing cell division, and leading to apoptosis. Carmustine can also generate isocyanate intermediates, which react with amino groups (-NH2) on proteins and alter enzyme structure and function. Carmustine can effectively cross the blood-brain barrier, so it has applications in chemotherapy settings involving central nervous system tumors.