A Quality by Design Approach to the Development and Validation of a Stability-Indicating RP-HPLC Method for Itraconazole in Bulk and Capsule Dosage from

Objective: To develop and validate a stability-indicating RP-HPLC method for the estimation of itraconazole in bulk drug and capsule formulation using a Quality by Design (QbD) approach. Methods: A QbD-based RP-HPLC method was developed and optimized using a Box–Behnken design based on response surface methodology. The effects of flow rate, percentage of organic mobile phase, and wavelength were evaluated on critical quality attributes, including retention time, number of theoretical plates, and tailing factor. Chromatographic separation was achieved on a Symmetry C18 column (250 × 4.6 mm, 5 µm) using a mobile phase consisting of methanol and 0.1% formic acid (50:50, v/v). The flow rate was maintained at 0.8 ml/min, detection was carried out at 253 nm, and the column temperature was set at 40 °C. The method was validated according to ICH guidelines. Results: Itraconazole eluted at a retention time of 3.142 min. Linearity was observed over the concentration range of 2–10 µg/ml with a correlation coefficient of 0.999. The limit of detection and limit of quantification were found to be 0.62 µg/ml and 1.89 µg/ml, respectively. The method was found to be accurate, precise, and linear over the tested concentration range. Furthermore, the method was demonstrated to be stability-indicating through stress degradation studies. Conclusion: The developed QbD-based stability-indicating RP-HPLC method was validated as per ICH guidelines and found to be accurate, precise, and robust. The method is suitable for routine quality control analysis of itraconazole in bulk and pharmaceutical dosage forms.