Temozolomide is an imidazotetrazine derivative and prodrug that functions as an alkylating agent. It is primarily utilized in oncology research and pharmaceutical development for glioblastoma multiforme (GBM) and anaplastic astrocytoma. Upon metabolic activation to MTIC, it methylates DNA at the O⁶-position of guanine, triggering DNA mismatch repair failure and apoptosis in rapidly dividing cancer cells. Its lipophilicity enables penetration of the blood-brain barrier, making it ideal for central nervous system tumor models. High-purity (≥99.0% HPLC) temozolomide is employed in cell culture studies, preclinical trials, drug synthesis, and mechanistic investigations of chemotherapy resistance.