Development and validation of a new high performance liquidchromatography method for the determination of roflumilast

Roflumilast is a non-steroidal anti-inflammatory phosphodiesterase-4 inhibitor used in the treatment of chronic obstructive pulmonary disease. In this MSc thesis, it was aimed to develop and validate a novel high performance liquid chromatography method with fluorescence detection for the quantification of roflumilast in tablet formulations. Separations were achieved by a C18 analytical column (250 × 4.6 mm, 5 µm) at 40ºC. Isocratic elution was applied with a mobile phase consisting of 20% aqueous o-phosphoric acid solution (0.08%) and 80% methanol. The excitation and the emission wavelengths were 290 and 380 nm, respectively. The linear range was 1.25-10.00 μg/mL. Irbesartan was used as the internal standard. Limits of detection and quantification were 0.07 μg/mL and 0.22 μg/mL, respectively. The precision and the accuracy of the method was determined at the concentrations of 1.25, 5.00 and 10.00 μg/mL. The recovery percent was calculated by the tablet solutions spiked at low, middle and high concentrations. The robustness of the method was tested in terms of flow rate, mobile phase composition and column temperature. The proposed method was successfully applied for the determination of roflumilast in tablet formulations with high precision and accuracy.