Roxithromycin API is a semi-synthetic macrolide antibiotic derived from erythromycin. It belongs to the 14-membered macrolide class and was developed to provide an orally active antibacterial agent with a longer duration of action than erythromycin. Roxithromycin is associated with antibacterial activity against a range of susceptible Gram-positive and selected Gram-negative microorganisms.
Roxithromycin is chemically identified by CAS 80214-83-1, with the molecular formula C₄₁H₇₆N₂O₁₅ and molecular weight 837.05 g/mol. The API is described in the Japanese Pharmacopoeia as a white crystalline powder.
Roxithromycin is an erythromycin derivative containing a characteristic 9-(E)-oxime ether side chain. Its macrolide structure enables interaction with the bacterial ribosomal system and inhibition of bacterial protein synthesis.
The API is freely soluble in ethanol (95%) and acetone, soluble in methanol and practically insoluble in water according to the JP XVII monograph.
Roxithromycin is a complex macrolide molecule containing multiple stereocenters, hydroxyl groups, glycosidic substituents and an oxime ether side chain. Because of its structural complexity, chromatographic control of related substances is an important part of API quality testing.
The pharmacopoeial impurity procedure specifically monitors several related substances and controls both individual and total related substances. The monograph also controls optical rotation on an anhydrous basis, which is particularly useful for confirming the characteristic stereochemical profile of the API.
Roxithromycin is a macrolide antibacterial API used in pharmaceutical development and manufacturing for formulations intended to treat susceptible bacterial infections.
Its antibacterial mechanism is primarily associated with binding to the 50S bacterial ribosomal subunit, thereby interfering with bacterial protein synthesis.
Historically, roxithromycin-containing medicines have been used for respiratory tract, urinary tract and soft-tissue infections caused by susceptible microorganisms.
Roxithromycin has established pharmacopoeial analytical requirements. Identification is performed by infrared spectroscopy, while potency is determined using liquid chromatography. JP XVII specifies an assay/potency range of 970–1020 mg potency per mg, calculated on the anhydrous basis.
Quality testing also includes:
The JP related-substances procedure limits the principal specified impurity to approximately 1.0%, other specified individual impurities to approximately 1.0%, and total related substances to approximately 3.0% based on the monograph's reference-solution calculation.
Manufacturing Roxithromycin API requires controlled synthesis, purification and crystallization to achieve consistent potency and impurity profiles. Because the molecule is a structurally complex macrolide, chromatographic separation and control of related substances are particularly important.
A quality-focused manufacturing process should maintain control over assay/potency, water, residue on ignition, heavy metals, related substances and stereochemical characteristics.
Roxithromycin should be packaged in tight pharmaceutical containers suitable for protecting the API from moisture and environmental contamination.
The JP XVII monograph specifies tight containers for Roxithromycin.
Storage conditions should follow the validated stability data for the specific API batch and packaging system.
Typical Roxithromycin API documentation may include:
Roxithromycin is a well-characterized macrolide antibacterial API with established pharmacopoeial testing requirements. Its defined chemical identity, controlled potency, related-substance profile, water limit, heavy-metal limit and optical-rotation requirement provide a strong analytical framework for pharmaceutical API quality.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Residue on Ignition | NMT 0.10% |
| Heavy Metals | NMT 10 ppm |
| Total Impurities | NMT 3.0% |
| Water Content | NMT 3.0% |
| Melting Point | −93° to −96° (anhydrous basis) |