Rimegepant Sulfate is a pharmaceutical active ingredient and the sulfate salt form of rimegepant, a small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist. It is used in pharmaceutical formulations for the acute treatment of migraine and the preventive treatment of episodic migraine in adults. The current FDA-approved NURTEC ODT product contains rimegepant sulfate equivalent to 75 mg of rimegepant per orally disintegrating tablet.
Rimegepant Sulfate is identified by CAS No. 1374024-48-2 and FDA UNII 1383NM3Q0H. The sulfate API is also known as rimegepant hemisulfate sesquihydrate. FDA identifies the drug substance as a crystalline sulfate hydrate with a defined solid-state form.
Rimegepant Sulfate is supplied as a white to off-white crystalline solid and is slightly soluble in water. FDA describes the pharmaceutical substance as the hemisulfate sesquihydrate, with an empirical formula of C28H28F2N6O3 · 0.5H2SO4 · 1.5H2O and molecular weight 610.63 g/mol.
The free-base rimegepant has CAS No. 1289023-67-1, molecular formula C28H28F2N6O3, and molecular weight 534.56 g/mol.
| Property | Details |
|---|---|
| Product Name | Rimegepant Sulfate |
| API Form | Rimegepant Hemisulfate Sesquihydrate |
| CAS Number | 1374024-48-2 |
| Free Base CAS | 1289023-67-1 |
| Molecular Formula | C28H28F2N6O3 · 0.5H2SO4 · 1.5H2O |
| Molecular Weight | 610.63 g/mol |
| FDA UNII | 1383NM3Q0H |
| Free Base Molecular Weight | 534.56 g/mol |
| Category | Small-Molecule Pharmaceutical API |
| Therapeutic Class | CGRP Receptor Antagonist |
| Appearance | White to off-white crystalline solid |
| Water Solubility | Slightly soluble |
| Pharmaceutical Form | Sulfate hydrate |
Important identity note: Some chemical databases represent the sulfate hydrate using a doubled molecular formula and report approximately 1221.2 g/mol. This is the doubled stoichiometric representation of the same hemisulfate sesquihydrate. FDA's pharmaceutical labeling uses the single-molecule representation and 610.63 g/mol, which is preferable for pharmaceutical product-page data.
Rimegepant is a selective CGRP receptor antagonist. The active pharmaceutical substance contains a stereochemically defined rimegepant molecule associated with hemisulfate and water of crystallization. FDA's chemistry review states that the drug substance structure and stereochemistry were adequately characterized, including confirmation by single-crystal X-ray crystallography.
The commercial drug substance is controlled for characteristics including identity, assay, related substances, residual solvents, sulfate content, residue on ignition, water content, particle size, crystalline form and microbiological quality.
*Values shown for the doubled sulfate-hydrate representation in PubChem.
Rimegepant Sulfate is used as the active pharmaceutical substance for rimegepant-containing medicines.
Current FDA labeling identifies NURTEC ODT as a CGRP receptor antagonist indicated for:
The marketed orally disintegrating tablet contains 75 mg rimegepant, equivalent to 85.7 mg rimegepant sulfate.
Rimegepant works by blocking the CGRP receptor and thereby inhibiting CGRP-mediated signaling involved in migraine pathophysiology.
Quality control of Rimegepant Sulfate requires a combination of identity, assay, impurity, physical-property and pharmaceutical-quality tests. FDA's CMC review confirms that the commercial drug substance is manufactured under controlled conditions and that its specification includes appearance, identification, related substances, residual solvents, sulfate content, residue on ignition, water content, particle size, crystalline form and microbiological controls.
Typical analytical techniques used for characterization include:
A publicly available commercial API specification reports 99.0–101.0% assay on an anhydrous basis, NMT 2.0% loss on drying, NMT 10 ppm heavy metals, NMT 0.5% residue/sulfated ash, NMT 0.10% unspecified individual impurity, and NMT 0.5% total impurities. These values should be regarded as a commercial manufacturer specification/reference specification, not as a universally applicable pharmacopoeial monograph.
Rimegepant Sulfate is a specialized pharmaceutical API requiring stereochemical control, crystalline-form control and comprehensive impurity characterization.
A number of Rimegepant Sulfate API manufacturers with regulatory/DMF evidence are reported internationally, including manufacturers in India. Public API-directory information identifies Indian organizations with FDA Type II DMF or EU CEP-related evidence for Rimegepant Sulfate.
A reliable Rimegepant Sulfate API manufacturing program should support:
Rimegepant Sulfate should be packaged in suitable well-closed, moisture-protective and light-protective pharmaceutical containers according to the validated storage requirements of the API manufacturer.
A commercial reference source recommends storage at 2–8°C for its Rimegepant Sulfate material. This should not automatically be treated as a universal regulatory storage condition for every API batch or manufacturer.
For commercial API supply, storage and transportation conditions should be established from the validated stability program and the batch-specific manufacturer documentation.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 2.0% |
| Residue on Ignition | NMT 0.1% |
| Heavy Metals | NMT 10 ppm |
| Individual Impurity | NMT 0.20% |
| Total Impurities | NMT 0.50% |
| Water Content | NMT 1.0% |