Research Article
Simultaneous Assay of Dexchlorpheniramine Maleate, Betamethasone, and Sodium Benzoate in Syrup by a Reliable and Robust HPLC Method
| Variation | Specific condition | Dexchlorpheniramine maleate | Sodium benzoate | Betamethasone | RSD (%) for peak area | RSD (%) for content in syrup | RSD (%) for peak area | RSD (%) for content in syrup | RSD (%) for peak area | RSD (%) for content in syrup |
| Flow rate (mL/min) | 0.8 | 0.1 | 0.4 | 0.1 | 0.4 | 0.3 | 0.4 | 1.0 (normal) | 0.2 | 0.6 | 0.2 | 0.6 | 0.4 | 0.5 | 1.2 | 0.4 | 0.4 | 0.1 | 0.9 | 0.3 | 0.8 |
| pH of 0.02 M phosphate buffer solution | 2.65 | 0.2 | 0.6 | 0.2 | 0.6 | 0.2 | 0.6 | 2.70 (normal) | 0.1 | 0.5 | 0.3 | 0.9 | 0.4 | 0.3 | 2.75 | 0.3 | 0.3 | 0.5 | 0.9 | 0.4 | 0.5 |
| Percentage of 0.02 M phosphate buffer in mobile phase | 64 | 0.1 | 0.5 | 0.2 | 0.9 | 0.2 | 0.5 | 65 (normal) | 0.1 | 0.6 | 0.3 | 0.5 | 0.3 | 0.7 | 66 | 0.1 | 0.4 | 0.2 | 1.1 | 0.5 | 0.4 |
| Wavelength of detector | 252 nm | 0.5 | 0.4 | 0.2 | 0.5 | 0.2 | 0.5 | 254 nm (normal) | 0.1 | 0.3 | 0.3 | 0.5 | 0.3 | 0.4 | 256 nm | 1.0 | 0.4 | 0.4 | 0.9 | 0.2 | 0.5 |
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