A synergistic chemometric combination for whiteness and greenness assessed HPLC-DAD assay of aqueous extracts of ivy and thyme and potassium sorbate in a syrup formula

Abstract

A stability-indicating fit-for-purpose method has been developed for co-determination of hederacoside C (HC), thymol (TL), and potassium sorbate (PS) combined in a syrup dosage form. Carvacrol (CL) was separated from thyme extract (THY) with demonstrated identity at high confidence. This method was based on a reversed-phase (RP) high performance liquid chromatographic (HPLC) separation of the cited analytes. The HPLC separation was performed on a RP Zorbax Eclipse XDB-C18 analytical column [250 × 4.6 mm, 5 µm (80 Å)] and SecurityGuard C18 guard column (4 × 3 mm, 5 µm) with gradient elution system of HPLC far UV grade acetonitrile and 20 mM aqueous potassium dihydrogen phosphate buffer adjusted to pH 2.1 as the mobile phase at a flow rate of 2.5 mL min−1 and column oven was set at 50 °C. Quantitation was achieved with the photodiode array detection (DAD) with interferent peak suppression. Target Measurement Uncertainty (TMU) was determined by misclassification rates approach employing 100,000 Monte Carlo simulations (MCS). The bias and imprecision standard deviation were combined as a total analytical error (TAE) and compared via an enhanced approach linked to product specifications, process variation, and shelf-life variability for proving a fit-for-purpose analytical procedure. The robustness of the method was checked using supersaturated design constructed from Plackett-Burman design (PB-SSD) which was statistically analysed via the very recent approach of autovalidation using self-validated ensemble modelling (SVEM). The calibration graphs for each analyte were rectilinear in the range of 42.12–560.00, 3.37–47.15 and 0.51–7.07 µg mL−1 for PS, HC, and TL, respectively. The proposed HPLC-DAD method was successfully applied for the determination of the investigated analytes in a syrup formula. Moreover, the whiteness and greenness of the procedure were assessed via the most recently cited approaches.