Development and Validation of related Substances method for Deflazacort Suspension by High Performance Liquid Chromatography using AQbD Approach

The stability-indicating method for Deflazacort Suspension was developed using the Analytical Quality by Design (AQbD) approach, focusing on process control and understanding. A multilevel factorial design was used to optimize the gradient mode's time and mobile phase ratio. Sophisticated software like Design Expert and Minitab aided in chromatographic condition optimization. The method utilizes a Zorbax Eclipse XDB C18 column (150mm x 4.6mm, 5µm particle size), with a flow rate of 1.0 mL/min, and monitoring the analyte with a UV/PDA detector at of 245nm wavelength known for its reliability. It employs two mobile phases: A, consisting of Water, Tetrahydrofuran, and Acetonitrile (91:3:6, v/v/v), and B, comprising Water, Tetrahydrofuran, Acetonitrile, and Methanol (4:2:74:20, v/v/v/v). Statistical analysis confirms the importance of these components in achieving effective separation and detecting related substances. The validation of method was done as per ICH guidelines. Linearity, specificity, Limit of Detection (LOD), Limit of Quantification (LOQ), precision, accuracy, solution stability, and robustness parameters were validated. The method was validated to ensure reliability and accuracy, demonstrating linearity from 0.02 to 1.2ppm with a correlation coefficient (r2 > 0.99) at 245nm. This confirms the method's ability to precisely quantify related substances in Deflazacort Suspension. The stability of Deflazacort Oral Suspension was rigorously assessed, including a forced degradation study. Critical system suitability parameters, tailing factor, and theoretical plate, met acceptable limits, confirming the method's efficiency and resolution. Successful separation of degradation peaks from each other and the main peak was achieved during the study. The method's robustness was confirmed with variations under 2%, ensuring consistent and reproducible results despite minor changes in conditions. Peak purity analysis showed no co-eluting peaks, confirming the method's specificity. These findings validate the stability-indicating nature of the chromatographic method for Deflazacort Oral Suspension analysis, ensuring its reliability for quality control.