Development and Optimisation of a Stability-Indicating Analytical Method for Itraconazole in Drug Product by High-Performance Liquid Chromatography Using a QbD Approach

Background/Objectives: In this study, an analytical method by high-performance liquid chromatography (HPLC) that allows the determination of the content of the active ingredient itraconazole (ITZ), as well as the quantification of its degradation products and known impurities, is developed. Some of the existing methods, including the compendial ones, present long run times or different methods for the quantification of ITZ and the quantification of its impurities. Methods: In this article, an initial screening approach, starting on the described compendial methods, was conducted in order to establish the initial working conditions of the chromatographic method parameters. Once these parametric conditions were established, an optimisation was conducted utilising a statistical approach and a Design of Experiments (DoE), with the objective of attaining an optimised method that allows the quantification of ITZ and its related substances in one single injection. The data obtained during the DoE were processed using the Minitab® statistical programme. Once an optimised method was obtained, a short pre-validation assessment studying the selectivity, linearity and system suitability, among others, was carried out, confirming the suitability of the method for the intended use. Results: The resulting method employs an isocratic mobile phase of acetonitrile (ACN) and buffer (ammonium phosphate 10 mM at pH 4.0), utilising a stationary phase of a Poroshell EC-C18 150 × 3.0 mm, 2.7 µm column. The retention time of itraconazole is 8.5–9.0 min, with a total chromatographic run time of 15 min. Conclusions: The developed method exhibits a shorter run time and greater environmental sustainability compared to compendial methods, underscoring its improved analytical performance.