Analytical quality-by-design (AQbD) approach for comprehensive analysis of bioactive compounds from Citrus peel...

The growing interest in ingredients from natural sources has expanded the need for quality assessments of plant extracts. Analytical quality-by-design (AQbD) has been increasingly applied in regulated environments such as pharmaceutical industries and, more recently, for the bioactive compounds found in botanical materials. This work aimed to obtain qualitative (overall resolution and maximum peak capacity) and quantitative performances for target analytes using AQbD principles. The analytical target profile was elaborated; critical method parameters (independent variables) that affect the critical method attributes (dependent variables) were selected from a risk assessment for a reversed-phase liquid chromatography with diode array detection (RPLC-DAD) method. YMC-Triart C18 (3.0 × 100 mm, 1.9 μm) and a gradient elution using 0.2% acetic acid and methanol:acetonitrile 1:3 (v/v) were chosen as the stationary and mobile phases, respectively. The optimal and robust conditions (temperature at 33.3 °C, flow rate of 0.68 mL.min^-1, and a gradient slope of 4.18%.min^-1) were established by the method operable design region (MODR). The validation was performed by accuracy profiles using 90% expectation tolerance intervals for the selected compounds found in Citrus spp. using C. japonica as blank matrix. The lower limits of quantification for hesperidin, bergapten, herniarin, and citropten were 5.32, 0.40, 0.49, and 0.52 mg.L^-1, respectively (acceptance limit was set at ± 20%). Nobiletin did not show an adequate quantitative performance.