Vidarabine

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Cat Number

API0231553

CAS Number

5536-17-4

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Product Detail Description Customer Q&A

CAS Number

5536-17-4

EINECS

226-893-9

Storage

Store at 2-8℃

Synonyms

Adenine arabinoside; Vira-A; Spongoadenosine; Araadenosine; Arasena-A; 9-beta-D-Arabinofuranosyladenine

Molecular Formula

C10H13N5O4

Molecular Weight

267.24

Smiles

C1=NC(=C2C(=N1)N(C=N2)[C@H]3[C@H]([C@@H]([C@H](O3)CO)O)O)N

Appearance

White to off-white powder

Melting Point

260-265℃

Boiling Point

410.43℃

Relative Density

1.3382

General Description

Vidarabine (adenine arabinoside) is a purine nucleoside analogue with antiviral activity against DNA viruses, primarily used as a topical ophthalmic preparation for herpes simplex keratitis. It was historically available in intravenous formulation for systemic herpes infections but has been largely replaced by newer agents. The drug is an analogue of deoxyadenosine that interferes with viral DNA synthesis.

Mechanism of Action

Vidarabine is phosphorylated intracellularly to the active triphosphate form, which competitively inhibits viral DNA polymerase more potently than host DNA polymerase. Once incorporated into viral DNA, it acts as a chain terminator due to the absence of a 3'-hydroxyl group on the arabinose sugar. This selective inhibition of viral DNA replication halts the production of new viral particles. The drug also has some inhibitory activity against host DNA synthesis at higher concentrations.

Application

Its current primary indication is the topical treatment of acute keratoconjunctivitis and recurrent epithelial keratitis caused by herpes simplex virus types 1 and 2. Ophthalmic vidarabine ointment is applied five times daily and is effective against acyclovir-resistant strains. Systemic use for herpes encephalitis or neonatal herpes has been superseded by acyclovir due to its superior efficacy, safety, and aqueous solubility. The ophthalmic formulation remains available but is less commonly used than trifluridine.

Does Vidarabine require refrigerated storage as a nucleoside antiviral?

Yes, it should be stored at 2-8°C for long-term stability. At room temperature, it can undergo deamination and other degradation pathways.

Is Vidarabine sensitive to light during handling and storage?

Yes, it is photosensitive. Store in light-resistant containers and handle under subdued light to prevent photodegradation.

What is the stability of Vidarabine after reconstitution for ophthalmic or intravenous use?

Reconstituted solutions have limited stability (typically 24-48 hours under refrigeration). We provide detailed in-use stability data for various diluents and storage conditions.

How is the impurity hypoxanthine arabinoside monitored during stability?

This primary deamination product is quantified using a stability-indicating HPLC method, ensuring it remains well below pharmacopoeial limits.