Temozolomide is known as the alkylating agent, which is used for the treatment of brain cancer. It is classified as the oral chemotherapy drug. It is used as a first-line treatment for the glioblastoma and second-line treatment of astrocytoma. The most common side-effect caused due to temozolomide includes the bone marrow suppression.
The therapeutic benefits of this drug directly depend on the ability of the drug to methylate or alkylate the deoxyribonucleic acid (DNA). The methylation caused by this drug result in the damage to the DNA, which further triggers the death of the tumor cells.
The proposed mechanism of action of the temozolomide is based on the ability of the metabolites of the temozolomide to deposit the methyl groups on the guanine bases of DNA. After the oral administration of the drug, the prodrug temozolomide is instantly absorbed by the small intestine with better penetration of the blood-brain barrier.
This occurs due to the small size of the drug. Further, it undergoes to the spontaneous intracellular conversion, which is facilitated by the hydrolysis into a viable methylating agent that is 5-(3-methyl-1-triazeno) imidazole-4-carboxamide (MTIC).
The MTIC methylates the number of nucleobases, including guanine. This step results in the nicks or breaks formation in the DNA, followed by the process of apoptosis. This is because the cellular repair mechanisms become unable to adjust according to the methylated bases.