Rufinamide

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Cat Number

API106308445

CAS Number

106308-44-5

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Product Detail Description Scientific Support Customer Q&A

CAS Number

106308-44-5

EINECS

808-195-1

Storage

Store at room temperature

Synonyms

Inovelon; Banzel; 1-(2,6-Difluorobenzyl)-1H-1,2,3-triazole-4-carboxamide; CGP-33101; RUF 331

Molecular Formula

C10H8F2N4O

Molecular Weight

238.19

Smiles

C1=CC(=C(C(=C1)F)CN2C=C(N=N2)C(=O)N)F

Melting Point

232-234°C

Boiling Point

473.8±55.0°C at 760 mmHg (Predicted)

Relative Density

1.52±0.1 (Predicted)

General Description

Rufinamide is a triazole derivative structurally unrelated to other anticonvulsants, featuring a 1,2,3-triazole ring linked to a difluorobenzyl group. This unique scaffold imparts a distinct mechanism of action. The molecule is highly lipophilic and exhibits a low protein binding affinity. Rufinamide is a white to practically white crystalline powder with limited aqueous solubility.

Mechanism of Action

Rufinamide prolongs the inactive state of voltage-gated sodium channels, reducing sustained repetitive firing of neurons. Unlike phenytoin or carbamazepine, it has minimal effect on fast inactivation and does not alter normal neuronal excitability. The drug also modulates the activity of calcium channels and enhances GABAergic transmission at higher concentrations. Its precise binding site on the sodium channel remains incompletely defined.

Application

Rufinamide is indicated as adjunctive therapy for seizures associated with Lennox‑Gastaut syndrome in children and adults. It is particularly effective against atonic seizures, a debilitating seizure type in this syndrome. The drug is also investigated for partial‑onset seizures and other refractory epilepsies.

This Cochrane review (6 trials, 1759 participants) evaluated add‑on rufinamide for drug‑resistant focal epilepsy. Rufinamide significantly increased the rate of ≥50% seizure reduction (RR 1.79, 95% CI 1.44‑2.22; moderate‑certainty evidence) but also increased treatment withdrawal (RR 1.83) and adverse events including headache, dizziness, somnolence, vomiting, nausea, fatigue, and diplopia. Seizure freedom was not significantly improved (RR 1.32, 95% CI 0.36‑4.86). The evidence is moderate to low certainty, and long‑term use data are lacking. Rufinamide is effective as short‑term add‑on treatment but has frequent adverse effects.

Fig. 1 Study flow diagram. (Panebianco M, et al., 2020)

References

Panebianco M, et al. Rufinamide add-on therapy for drug-resistant epilepsy. Cochrane Database Syst Rev. 2020;11(11):CD011772.

Does Rufinamide require protection from light during long-term storage?

Yes, it is photosensitive. UV exposure can cause photodegradation of the triazole ring. Store in light-resistant containers, preferably original opaque packaging.

What is the recommended storage temperature for Rufinamide?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can accelerate hydrolysis of the carboxamide group.

Is Rufinamide stable under high-humidity conditions?

It is slightly hygroscopic. Under high humidity (>70% RH), it may absorb moisture and clump. Storage in tightly sealed containers with desiccant is recommended.

How is the impurity 1-(2,6-difluorobenzyl)-1H-1,2,3-triazole-4-carboxylic acid (hydrolysis product) monitored?

This degradation product is quantified using a stability-indicating HPLC method, ensuring it remains within ICH qualification thresholds.