Is a DoE-based approach superior to OFAT for HPLC robustness assessment under ICH Q14? A practical case study

Area of Science:

• Analytical Chemistry
• Pharmaceutical Development
• Method Validation

Background:

• Method robustness is crucial for reliable analytical results in pharmaceutical research.
• Traditional one-factor-at-a-time (OFAT) methods have limitations in assessing robustness.
• A systematic comparison between Design of Experiments (DoE) and OFAT for robustness evaluation is needed.

Purpose of the Study:

• To compare the effectiveness of DoE versus OFAT for assessing the robustness of a liquid chromatography method.
• To identify key factors and interactions influencing method robustness.
• To evaluate the efficiency and regulatory implications of each approach.

Main Methods:

• A liquid chromatography method's robustness was evaluated using both DoE and OFAT strategies.
• Key parameters including flow rate, temperature, and mobile phase composition were systematically varied.
• Responses were analyzed to identify significant factors, interactions, and define a design space.

Main Results:

• DoE identified organic solvent content and pH as primary factors affecting method performance and revealed critical factor-factor interactions.
• OFAT provided limited insights, required more resources, and failed to detect interactions.
• OFAT indicated robustness except at higher pH, while DoE identified additional non-robust conditions due to interactions.

Conclusions:

• DoE is superior to OFAT for robustness assessment, offering enhanced analytical understanding and efficiency.
• DoE enables the definition of a flexible, robust design space, improving regulatory compliance.
• Integrating DoE into routine robustness testing strengthens method reliability and adherence to pharmaceutical guidelines.