Isonicotinic acid, readily identified by its Chemical Abstracts Service (CAS) number 55-22-1, is a pivotal chemical compound that serves as a foundational intermediate in the pharmaceutical industry. Often referred to by its synonym, 4-Pyridinecarboxylic acid, this molecule holds the chemical formula C6H5NO2. Its physical form is typically a white or light brown crystalline powder, a characteristic that aids in its handling and integration into various synthesis processes. With a high purity standard of ≥99%, it is highly valued for applications where precision and minimal impurities are critical.

The primary utility of isonicotinic acid lies in its role as a precursor for synthesizing important active pharmaceutical ingredients (APIs). Most notably, it is an essential intermediate for the production of Fexofenadine, a widely prescribed antihistamine known for its efficacy and lack of sedative effects. The synthesis of Fexofenadine hydrochloride, a common salt form, requires a reliable supply of high-quality isonicotinic acid to ensure the potency and safety of the final drug product. Manufacturers seeking to buy this intermediate often look to established suppliers, including those based in China, for consistent quality.

Another critical application of isonicotinic acid is in the manufacturing of Isoniazid. This medication is a cornerstone of tuberculosis (TB) treatment regimens worldwide. The global effort to combat TB necessitates a steady and dependable supply of essential medicines, making isonicotinic acid a compound of significant public health importance. Pharmaceutical companies producing Isoniazid rely on the consistent purity and chemical integrity of isonicotinic acid to maintain efficient production cycles and meet the ongoing demand.

The physical and chemical properties of isonicotinic acid are well-defined, including a density of 1.293 g/cm³ and a melting point exceeding 300°C. These attributes, along with its low impurity levels (e.g., ≤0.01% for impurities, ≤0.5% drying loss, ≤0.1% residue), make it a robust and reliable chemical intermediate. When sourcing this compound, attention to its specifications and packaging (often in 25kg cardboard drums) is vital for maintaining its quality during transit and storage.

In conclusion, the significance of isonicotinic acid, denoted by CAS 55-22-1, in the pharmaceutical industry cannot be overstated. Its critical function as an intermediate for producing vital drugs like Fexofenadine and Isoniazid makes it a key component for manufacturers. For companies looking to secure this essential chemical, prioritizing purity and reliable sourcing from reputable manufacturers is essential for product success.