Moxonidine API is a centrally acting antihypertensive pharmaceutical active ingredient belonging to the imidazoline receptor agonist class. It is primarily associated with the management of hypertension and acts on receptors involved in the regulation of sympathetic nervous system activity. Moxonidine is a well-characterized small-molecule API used in pharmaceutical formulations for blood-pressure management.
Moxonidine has the molecular formula C₉H₁₂ClN₅O and a molecular weight of 241.68 g/mol. Its CAS number is 75438-57-2 and its FDA Global Substance Registration System UNII is CC6X0L40GW. The IUPAC name is 4-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-6-methoxy-2-methylpyrimidin-5-amine.
Moxonidine produces its pharmacological effects through activity at imidazoline receptors, particularly receptors involved in central regulation of sympathetic outflow. Its centrally acting mechanism reduces sympathetic nervous system activity, which contributes to a reduction in blood pressure.
Moxonidine is therefore pharmacologically distinct from conventional antihypertensive classes such as ACE inhibitors, calcium-channel blockers and thiazide diuretics.
Moxonidine is used as an antihypertensive pharmaceutical ingredient for the treatment of hypertension. Its established pharmacological activity makes it relevant to cardiovascular pharmaceutical development and formulations intended for blood-pressure management.
Moxonidine is a defined small-molecule chemical compound. PubChem identifies it as an organohalogen compound and a member of the pyrimidine class. Its chemical structure contains a chlorinated pyrimidine ring, methoxy group and imidazoline moiety.
The API should be characterized using validated analytical procedures appropriate to its applicable pharmacopoeial or approved specification.
Moxonidine is included in the British Pharmacopoeia (BP). The BP monograph includes identification, related-substances testing and assay by liquid chromatography. The monograph also specifies limits for identified and unspecified impurities.
The BP-related-substances procedure identifies impurities A and B as specified impurities, with other detectable impurities designated C and D. The monograph establishes limits of 0.3% for impurity A, 0.3% for impurity B, 0.10% for each unspecified impurity, and 0.5% for total impurities.
The BP assay for Moxonidine uses liquid chromatography and calculates the percentage content of C₉H₁₂ClN₅O with reference to assigned-content Moxonidine CRS. This provides a pharmacopoeial basis for quantitative API assessment.
The BP monograph also specifies loss on drying of not more than 0.5%, determined at 105 °C for three hours, and sulfated ash of not more than 0.1%.
Moxonidine API is relevant to pharmaceutical formulation development, analytical testing and manufacturing of oral antihypertensive products. Its defined chemical identity and established pharmacopoeial testing requirements support quality evaluation throughout API and finished-product development.
Moxonidine API should be stored and handled according to the applicable manufacturer's validated stability data, Certificate of Analysis and approved storage specification. Temperature, humidity, packaging and protection requirements should be established using appropriate stability studies rather than assumed from generic API storage practices.
For commercial pharmaceutical applications, Moxonidine should be evaluated according to the applicable BP or other recognized pharmacopoeial standard, together with the manufacturer's approved specification. Important quality attributes include identity, assay, related substances, loss on drying and sulfated ash.
Batch-specific quality should be confirmed through appropriate analytical documentation and a current Certificate of Analysis (CoA).
| Parameter | Specification |
|---|---|
| Appearance | White crystalline powder or crystals |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |