The purpose of this paper is to summarize the fundamentals, benefits and limitations of various models of Design of Experiments (DoE) such as 2-Level Full Factorial Design, Central Composite Design (CCD), and Box–Behnken Design (BBD) while establishing a comparison between these models by taking the Metronidazole immediate release (IR) tablets as a case study. Metronidazole IR tablets were prepared by wet granulation method. The Quality Target Product Profile (QTPP) and Critical Quality Attributes (CQA) were selected based on literature review and prior knowledge about the formulation. Critical Material Attributes (CMA) (concentration of binder, super disintegrant, and glidant), and Critical Process Parameters (CPP) (compression of the tablets) were identified based on their risk to the CQA. Screening and optimization of the CMA were performed using DoE. From the Full Factorial Design, it was observed that the disintegration time and dissolution at 30 min were significantly influenced by the selected CMAs. These significant factors were further optimized using CCD and BBD to achieve the constraints (minimum disintegration and maximum dissolution). The levels of povidone K30, crospovidone, and magnesium stearate were optimized to 10 mg, 32 mg, and 1.6 mg respectively using CCD and BBD.
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