Technical Information
According to pharmacopoeias, many drugs are prescribed to be analyzed by high pressure liquid chromatography (HPLC) using conventional column dimensions and parameters. The United States Pharmacopeia (USP) and the International Harmonization of Pharmacopoeias allow for changes in LC parameters to the extent that they fulfill system suitability requirements for UHPLC.
The permissible adjustment to LC parameters under isocratic elution conditions in International Harmonization of Pharmacopoeias (Stage 4) is shown below.
| Stationary phase | Unchangeable |
|---|---|
| Particle size (dp) | L/dp is changeable in the range of −25% to +50% |
| Column length (L) |
| pH | ±0.2 |
|---|---|
| Salt concentration of buffer solution | ±10% |
| Solvent composition | The minor solvent composition is changeable in the greater of ±30% (relative) or ±2% (absolute). |
| Flow rate | F2 = F1 x [(dc22 x dp1)/(dc12 x dp2)] F1：original frow rate F2：modified flow rate dc1：original column inner diameter dc2：modified column inner diameter dp1：original particle size dp2：modified particle size When the particle sizes are changed from ≥ 3 µm to < 3 µm, F2 is changeable within the range of ±50% if the column efficiency does not decrease by more than 20%. |
|---|---|
| Temperature | ±10°C |
| Detector wavelength | Unchangeable |
| Injection volume | If the column dimension is changed, the injection volume is changeable according to the below equation. Vinj2 = Vinj1 x [(L2 x dc22)/(L1 x dc12)] Vinj1：original injection volume Vinj2：modified injection volume L1：original column length L2：modified column length dc1：original column inner diameter dc2：modified column inner diameter Even if the column dimension is not changed, the injection volume is changeable within the range fulfilling the system suitability requirements. |
*Please refer to the original article written by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH).
