Dutasteride EP Impurity A, chemically defined as 3-Oxo-4-aza-5α-androst-1-ene-17β-carboxylic acid and also known as Dutasteride Acid Impurity, is a carboxylic acid intermediate impurity of Dutasteride, with molecular formula C₁₉H₂₇NO₃ and molecular weight 317.43 g/mol. Structurally, this compound is the free 17β-carboxylic acid precursor of the parent 5α-reductase inhibitor; it is converted to Dutasteride by amide coupling with 2,5-bis(trifluoromethyl)aniline, and it can also be formed by hydrolysis of the 17β-carboxamide. Its presence therefore reflects incomplete coupling or intermediate carryover, making it a key synthetic marker for monitoring coupling-reaction completeness and process purity (the same 4-azasteroid acid is also a key intermediate of Finasteride). Manufactured at Chemicea under tightly controlled synthetic and purification protocols, this reference standard supports impurity identification, method validation (AMV), and quality-control testing in accordance with EP monograph requirements for Dutasteride, and is routinely used in ANDA and DMF regulatory submissions. 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. 104239-97-6 | Explore complete technical documentation, Safety Data Sheet (SDS), and pricing.