Trifluridine (also called trifluorothymidine; abbreviation TFT or FTD) is an anti-herpesvirus antiviral drug, used primarily as prescription eyedrops. It was sold under the trade name Viroptic by Glaxo Wellcome, now merged into GlaxoSmithKline. The brand + some more technical info Trifluridine is a 5-trifluoromethyl substituted pyrimidine nucleoside analogue of thymidine that is phosphorylated intracellularly to active mono, di and triphosphate species; the triphosphate form is incorporated into viral DNA and disrupts chain elongation and base pairing, producing potent inhibition of herpes simplex virus replication in corneal epithelial cells. The marketed ophthalmic formulation was typically 1 percent solution for topical ocular use in herpes simplex keratitis; systemic uses differ and trifluridine is also a component of the oral antineoplastic combination with tipiracil where the pharmacology and safety profile are distinct from topical ocular therapy. Key physicochemical points are that trifluridine is polar, water soluble enough for aqueous ophthalmic formulations, and subject to enzymatic phosphorylation and to hydrolytic and oxidative degradation under forced conditions, which informs its formulation and storage requirements.
Parent: Trifluridine
In quality control and stability testing, related substances monitored for trifluridine include nucleoside hydrolysis products, deoxyribose cleavage products, oxidative degradation products, positional or stereoisomeric impurities and phosphorylated metabolites where applicable for biological samples. Typical analytical practice follows ICH Q3A/B concepts with reporting and qualification thresholds: a reporting threshold commonly set at 0.05 percent and a qualification threshold commonly set at 0.15 percent. Acceptance criteria used for drug substance and finished ophthalmic product testing frequently target individual unidentified impurities not to exceed about 0.2 to 0.5 percent and total impurities not to exceed about 1.0 percent, while known specified impurities have defined limits based on safety and toxicology data. Methods for related-substance testing are usually HPLC with UV or MS detection and are stability-indicating to separate and quantify these impurities.
Trifluridine is used topically as an ophthalmic antiviral for treatment of herpes simplex virus infections of the eye, primarily epithelial keratitis; it inhibits viral DNA synthesis after intracellular phosphorylation.
As a single agent in topical ophthalmic form trifluridine is an antiviral, not a systemic chemotherapy. However, trifluridine is also used systemically in combination with tipiracil as an antineoplastic agent, so the same chemical can be part of a chemotherapy regimen when formulated and dosed for systemic oncology use.
Trifluridine is a pyrimidine nucleoside analogue of thymidine and is classified pharmacologically as an antiviral nucleoside analogue that inhibits viral DNA replication after phosphorylation.
No. Zirgan is the trade name for ganciclovir ophthalmic gel, which contains a different antiviral active ingredient with a different chemical structure and dosing regimen. Trifluridine and ganciclovir are distinct drugs used to treat ocular viral infections, and they are not interchangeable without clinical guidance.
