Phenacemide is a synthetic ureide anticonvulsant also known as Phenurone, Phenylacetylurea, and Phenacetylurea. It was historically used as an antiepileptic drug for the treatment of seizures and belongs to the acetylurea class of anticonvulsant compounds. Phenacemide is structurally related to phenytoin and other ureide anticonvulsants. (pubchem.ncbi.nlm.nih.gov)
Phenacemide has the CAS Number 63-98-9, molecular formula C9H10N2O2, and molecular weight 178.19 g/mol. Its systematic chemical name is N-carbamoyl-2-phenylacetamide. These chemical identity details are supported by PubChem, NIST and CAS Common Chemistry. (pubchem.ncbi.nlm.nih.gov)
Phenacemide contains a phenylacetyl group linked to a urea functional group. Its chemical structure is represented by the molecular formula C9H10N2O2, with an exact mass of approximately 178.0742 Da. PubChem lists Phenacemide under PubChem CID 4753, ChEBI CHEBI:8049, ChEMBL CHEMBL918, DrugBank DB01121, and KEGG D00504. (pubchem.ncbi.nlm.nih.gov)
NIST independently reports the molecular weight as 178.1879 g/mol and CAS Registry Number 63-98-9. (webbook.nist.gov)
CAS Common Chemistry reports a melting-point range of 212–216°C, which is consistent with historical chemical references. (commonchemistry.cas.org)
Phenacemide was introduced historically for epilepsy treatment and was subsequently withdrawn because of toxicity concerns. It is therefore important to distinguish Phenacemide from currently marketed modern antiepileptic APIs. PubChem identifies its historical anticonvulsant use, while historical literature documents its use in difficult-to-control epilepsy. (pubchem.ncbi.nlm.nih.gov)
Phenacemide has also been used as an analytical reference compound. Published pharmaceutical research describes chromatographic methods for determining Phenacemide in tablets and biological samples. A 1982 Journal of Pharmaceutical Sciences paper reported a gas chromatographic assay for Phenacemide in tablets, while a 1986 publication described an HPLC assay for Phenacemide in tablets. (pubmed.ncbi.nlm.nih.gov)
Phenacemide can be characterized by spectroscopic and chromatographic techniques. Historical pharmaceutical analysis has used GLC and HPLC for quantitative determination. A published HPLC method was also developed for measuring Phenacemide concentrations in plasma during clinical treatment. (pubmed.ncbi.nlm.nih.gov)
For API quality control, identification can include infrared spectroscopy and chromatographic comparison. Assay and impurity testing can be performed using validated chromatographic methods suitable for the substance.
Phenacemide is an older pharmaceutical substance, and a current publicly accessible USP, Ph. Eur. or Indian Pharmacopoeia monograph with a complete set of modern numerical API-release specifications could not be verified from the authoritative sources reviewed.
Therefore, values such as 98–102% assay, individual impurity limits, total impurity limits, loss on drying, residue on ignition, heavy metals and residual solvents should not be presented as current universal pharmacopoeial requirements unless supported by the specific applicable monograph or approved manufacturer specification.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.2% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Melting Point | 212–216° |