Foscarnet Sodium API is the trisodium salt of phosphonoformic acid and belongs to the antiviral class of pharmaceutical compounds. It is a pyrophosphate analogue that inhibits viral DNA polymerases and is used in pharmaceutical formulations for antiviral therapy. Foscarnet Sodium has CAS Number 34156-56-4 in its pharmacopoeial hexahydrate form, with the molecular formula CNa₃O₅P·6H₂O and molecular weight 300.04 g/mol.
Foscarnet Sodium is also known as phosphonoformic acid, trisodium salt, hexahydrate. The anhydrous trisodium salt has the formula CNa₃O₅P and molecular weight 191.95 g/mol, while the USP drug substance is specified as the hexahydrate.
| Property | Value |
|---|---|
| CAS Number | 34156-56-4 |
| Molecular Formula | CNa₃O₅P·6H₂O |
| Molecular Weight | 300.04 g/mol |
| Anhydrous Molecular Weight | 191.95 g/mol |
| Chemical Name | Phosphonoformic acid, trisodium salt, hexahydrate |
| Appearance | White to off-white powder |
The USP monograph specifically identifies Foscarnet Sodium as the hexahydrate with molecular weight 300.04.
Foscarnet Sodium has an established USP monograph. USP specifies 98.5%–101.0% of foscarnet sodium, calculated on the dried basis. The monograph also specifies pH 9.0–11.0 and loss on drying of 35.0%–37.0%, consistent with the hexahydrate form.
Foscarnet Sodium is an antiviral pharmaceutical ingredient used particularly in the management of cytomegalovirus (CMV) infections, including CMV retinitis, and has activity against herpesviruses.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.5% – 101.0% |
| Loss on Drying | NMT 5.0% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 9.0 – 11.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |