5 Fluorocytosine CAS 51-21-8

5 Fluorocytosine, referred to as fluorouracil, is an antimetabolic drug of pyrimidine class. It is a chemotherapy drug commonly used in clinic at present. It has an effect on each stage of proliferation, can prevent the formation of thymine, inhibit the biosynthesis of DNA, and thus inhibit the growth of cancer cells. It is clinically used to treat gastrointestinal tumors, such as gastric cancer, intestinal cancer, liver cancer, etc. It is also effective against breast cancer, ovarian cancer, lung cancer, bladder cancer, cervical cancer and pancreatic cancer.

5-fluorouracil is first transformed into 5-fluoro-2-deoxyuracil nucleotide in vivo, inhibits thymine nucleotide synthetase, and blocks the transformation of uracil deoxynucleotide into thymine deoxynucleotide, thus affecting DNA biosynthesis. At the same time, it can incorporate RNA, and directly inhibit the synthesis of RNA by blocking the incorporation of uracil and whey acid into RNA. This drug is mainly catabolic in the liver, most of it is decomposed into carbon dioxide and excreted from respiration, and very little is excreted by urine. 5 Fluorocytosine was more toxic to proliferating cells than to non-proliferating cells, but there was no significant cell cycle specificity. Resistance to fluorouracil can be the result of a lack of enzymes necessary for active action or an increase in thymidylate synthase activity.