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5-Fluorocytosine (5-FC) Solution
5-Fluorocytosine (5-FC) Solution is a fluorinated cytosine analog that is used as an antifungal agent.
5-fluorocytosine (5-FC) also known as Flucytosine. 5-Fluorocytosinewas first synthesized in 1957 as anti-tumor drug. It is an antifungal medication which is used with amphotericin B against Candida infections and cryptococcosis. This drug is mainly taken by mouth and by injection into a vein.
There are different modes of reproduction in fungi such as sexual, asexual, and vegetative modes of reproduction….microbiologynote.com
Mechanism or Mode of Action of 5-Fluorocytosine
First Candida species take the 5-Fluorocytosine via the cytosine permease and once inside the cell, it is rapidly converted into 5-fluorouracil (5-FU). The 5-FU is toxic to mammalian cell, whereas 5-FC is quite safe.
This 5-FU can exert its toxic effect by adopting two different pathways inside the cell. In one pathway, 5-FU is converted into 5-Fluorodeoxyuridine monophosphate (FdUMP) which is proven to be a potential inhibitor of thymidylate synthase, an essential enzyme for biosynthesis of thymidine. As a result, DNA synthesis gets blocked in fungal cells and it is unable to go for cell division.
Another mechanism is through the conversion of 5-FU into 5-fluorouridine monophosphate and subsequently into 5-Fluorouridine triphosphate which is incorporated into RNA in place of normal uridine triphosphate. In turn, this inhibits the protein synthesis in fungal cell.
Application of 5-Fluorocytosine
- It is used for the treatment of infections caused by Candida or Cryptococcus neoformans.
- It also used for the treatment of chromomycosis (chromoblastomycosis).
Side effects of 5-Fluorocytosine
There are several side effects of 5-Fluorocytosine such as;
- The treated patient can lead to bone marrow suppression, where the production of leukocytes and erythrocytes is decreased. It also termed as myelotoxicity or myelosuppression.
- loss of appetite
- It can cause diarrhea, and vomiting.
- It can cause psychosis.
- Sometimes it’s responsible for Anaphylaxis and other allergic reactions.
5-Fluorocytosine (5-FC) Solution Preparation
To prepare 1L of 5-Fluorocytosine (5-FC) Solution the following components are require;
|5-FC (mw: 129.09 g/mol)||10 g||0.0775 M|
- Prepare 800 mL of distilled water in a suitable container.
- Add 10 g of 5-FC to the solution.
- Add distilled water until volume is 1 L.
- Vortex. Incubate for 2 h at 37°C, manually mixing the solution every 15 min until the 5-FC dissolves. Filter the solution and use it immediately. Alternatively, aliquot into sterile tubes and store at -20°C.
- “5-Fluorocytosine (5-FC) Solution Preparation.” AAT Bioquest, Inc, 30 Apr. 2021, https://www.aatbio.com/resources/buffer-preparations-and-recipes/5-fluorocytosine-5-fc-10-mg-ml.
- Candida Infections and Their Prevention – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Schematic-diagram-of-the-effect-of-5-Fluorocytosine-5-FC-on-the-fungal-cell-Genes-for_fig1_258405099 [accessed 30 Apr, 2021]