Fluorouracil is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances from becoming incorporated into DNA during the "S" phase (of the cell cycle), stopping normal development and division. Fluorouracil blocks an enzyme which converts the cytosine nucleotide into the deoxy derivative. In addition, DNA synthesis is further inhibited because Fluorouracil blocks the incorporation of the thymidine nucleotide into the DNA strand. Fluorouracil is used for the topical treatment of multiple actinic or solar keratoses. In the 5% strength it is also useful in the treatment of superficial basal cell carcinomas when conventional methods are impractical, such as with multiple lesions or difficult treatment sites. Fluorouracil injection is indicated in the palliative management of some types of cancer, including colon, esophageal, gastric, rectum, breast, biliary tract, stomach, head and neck, cervical, pancreas, renal cell, and carcinoid.

10-Hydroxycamptothecin (10-HCPT), an indole alkaloid isolated from a Chinese tree, Camptotheca acuminate, inhibits the activity of topoisomerase I and has a broad spectrum of anticancer activity in vitro and in vivo. However, its use has been limited due to its water-insolubility and toxicity with i.v. administration. Prolonged elimination of 10-HCPT in vivo may have a significant impact on its therapeutic effects. 10-HCPT is metabolized to its carboxylate form and glucuronides.It was investigated that relatively low dose of 10-HCPT is able to inhibit the growth of colon cancer, facilitating the development of a new protocol of human trials with this anticancer drug.

Mureletecan is a water-soluble prodrug, consisting of camptothecin covalently linked to polymeric backbone methacryloylglycynamide, with potential antineoplastic activity. After entering tumor cells, the active moiety camptothecin is slowly released from mureletecan via hydrolysis of the ester linkage. Camptothecin, the active moiety, is an alkaloid isolatable from the Chinese tree Camptotheca acuminata. Camptothecin itself suffers from poor solubility, which is why it is often investigated with a solubilizing conjugate; such as in Mureletecan. Camptothecin binds to and stabilizes the topoisomerase I-DNA covalent complex producing potentially lethal double-stranded DNA breaks when encountered by DNA replication machinery. Camptothecin has also been shown to inhibit HIF1a. Camptothecin has been investigated with a number of solubilizing conjugates as a potential treatment in various forms of cancer.