Chemical Name:Darifenacin hydrobromide
CAS:133099-07-7
Synonyms:3-(2-(4-(2,2-Diphenylbutyryloxy)piperidin-1-yl)ethyl)-2,3-dihydro-1H-benzofuran-7-carbonitrile hydrobromide
Molecular Formula:C<sub>28</sub>H<sub>30</sub>N<sub>2</sub>O<sub>2</sub>·HBr
Molecular Weight:507.47 g/mol (hydrobromide salt)
Appearance:White to off-white crystalline powder
Solubility:Sparingly soluble in water; soluble in methanol, ethanol, and DMSO
Melting Point:~210–215°C (with decomposition)
pKa:~9.5 (tertiary amine)
Partition Coefficient (LogP):~3.8 (lipophilic)
Stability:Stable under recommended storage (2–8°C, protected from moisture)
Pharmacological Class:Muscarinic receptor antagonist (M<sub>3</sub> selective)
Primary Use:Treatment of overactive bladder (OAB) (urinary urgency, frequency, and incontinence)
Darifenacin Hydrobromide – Quality Control Specifications
| Test Parameter | Specification | Method (Reference Standard) |
|---|
| Appearance | White to off-white crystalline powder | Visual (EP/USP) |
| Identification | - HPLC retention time matches reference standard
- IR spectrum conforms | HPLC, FTIR (vs. USP standard) |
| Assay (Purity) | 98.0% – 102.0% (anhydrous basis) | RP-HPLC (UV detection at 210 nm) |
| Water Content | ≤ 1.0% (Karl Fischer) | Karl Fischer titration |
| Related Substances | - Single impurity: ≤ 0.5%
- Total impurities: ≤ 1.5% | HPLC (gradient, ICH Q3B) |
| Residual Solvents | - Class 1 solvents: Not detected
- Class 2/3: Meets ICH Q3C limits | GC (Headspace) |
| Heavy Metals | ≤ 10 ppm (as per ICH Q3D) | ICP-MS |
| Sulfated Ash | ≤ 0.1% | USP <281> |
| pH (1% solution) | 4.0 – 6.0 | Potentiometry |
| Particle Size | D90 ≤ 100 μm (if specified for formulation) | Laser diffraction |
| Microbial Limits | - TAMC ≤ 10³ CFU/g
- TYMC ≤ 10² CFU/g
- Pathogens: Absent | USP <61>, <62> |
| Specific Rotation | +20° to +25° (c=1 in methanol) | Polarimetry |
| Dissolution | ≥ 80% release in 45 min (pH-dependent, e.g., pH 1.2 & 6.8 buffers) | USP Apparatus II (Paddle) |
China
