SIMULTANEOUS HPLC-DETERMINATION OF NORTRIPTYLINE AND FLUPHENAZINE IN ONE MINUTE USING MONOLITHIC STATIONARY PHASE

Abstract

A simple, fast, robust, and accurate high-performance liquid chromatography (HPLC) method is described for simultaneous quantification of nortriptyline and fluphenazine in bulk powder and dosage forms. The chromatographic separation was carried out in less than one minute on Chromolith® Performance RP-18e column, which consists of monolithic rods of highly porous silica, using isocratic binary mobile phase of MeOH and 25 mM KH₂PO₄ pH 4.5 in the ratio of 70: 30 at 5 mL min⁻¹ flow rate and 40°C. The high porosity of stationary phase enables it to be used at high flow rates without problems concerning backpressure, these high flow rates in turn lead to strong reduction of analysis time. A diode array detector was used at 254 nm for detection. The method was validated for system suitability, linearity, precision, limits of detection and quantitation, specificity, and robustness. LOD were found to be 0.40 and 0.78 µg mL⁻¹ for nortriptyline and fluphenazine, respectively. LOQ was 3.125 µg mL⁻¹ for both analytes. Recovery values of this method were 98.50 and 98.00% for nortriptyline and fluphenazine, respectively, and reproducibility was within 2.36%. Robustness study was done for small changes in KH₂PO₄ concentration and pH, temperature, flow rate, wavelength of detection, % of MeOH in mobile phase, and injection volume.

Keywords:

• fast LC-determination
• fluphenazine
• monolithic column
• nortriptyline

ACKNOWLEDGMENT

H. Hashem received a two months post-doctorate Grant during this study from the German Research Society, DFG (Deutsche Forschungsgemeinschaft).

Notes

*coefficient of variation (%) = S.D. × 100/mean.

**accuracy (%) = observed concentration × 100/used concentration.

*The figures in parenthesis are the theoretical values for t- and f-test at p < 0.05.