Famotidine EP Impurity G, chemically defined as N-Cyano-3-[[[2-[(diaminomethylidene)amino]thiazol-4-yl]methyl]sulfanyl]propanimidamide and commonly known as Famotidine Cyanoamidine, is a process-related amidine impurity of Famotidine, with molecular formula C₉H₁₃N₇S₂ and molecular weight 283.37 g/mol. Structurally, this analog shares the full guanidinothiazolylmethylthio-propanimidamide skeleton of the parent H2-receptor antagonist but carries an N-cyano group in place of the N-sulfamoyl group on the amidine. It is a by-product associated with cyanamide-type reagents or alternative amidine-forming routes used during Famotidine synthesis. Owing to its close structural similarity to the API, this impurity is a critical reference marker for chromatographic specificity, synthetic-route selectivity, and process-related purity control in Famotidine drug substance manufacturing. Manufactured at Chemicea under tightly controlled synthetic and analytical protocols, this reference standard supports impurity identification, method validation (AMV), and quality-control testing in accordance with EP monograph requirements, and is routinely applied in ANDA and DMF regulatory filings for Famotidine. Each batch is supplied with a comprehensive Certificate of Analysis supported by HPLC, ¹H-NMR, and Mass Spectrometry characterization data, ensuring dependable analytical traceability for pharmaceutical R&D and QC laboratories worldwide. CAS No. 76823-97-7 | Explore complete technical documentation, Safety Data Sheet (SDS), and pricing.