Green analytical quality by design RP-HPLC technique with fluorimetric detection for simultaneous assay of...

A green and sensitive factorial design-assisted reversed-phase high-performance liquid chromatography (RP-HPLC) approach with fluorimetric detection has been developed for simultaneous determination of cinnarizine and domperidone in pure materials, commercial single and combined tablets. Both drugs are co-formulated in one dosage form and are commonly used for the effective treatment of motion sickness in the ratio of 4 : 3 for cinnarizine and domperidone, respectively. To achieve the developed method's best performance and reliability, a 2³ full factorial design was applied during the optimization of chromatographic conditions. Subsequently, isocratic elution on a C18 column with a mobile phase mixture of methanol and 0.02 M potassium dihydrogen phosphate buffer (85 : 15 v/v, pH 3.0) was performed to achieve the best separation. Moreover, the flow rate of 0.8 ml min^-1 was applied during the analysis with fluorescence detection at λ_ex 283 nm/λ_em 324 nm. The elution process was time effective; it consumed less than 6 min for a complete run as retention time for cinnarizine and domperidone, was 4.5 and 3.5, respectively. Good linearity of the proposed method was achieved within the concentration ranges of 0.2-4.5 and 0.4-5.0 µg ml^-1 for domperidone and cinnarizine, respectively. The suggested approach was carefully validated according to the International Council for Harmonization (ICH) guidelines. Moreover, green analytical procedure index (GAPI), national environmental methods index (NEMI), analytical greenness (AGREE) and analytical eco-scale methods were applied to assess and confirm method greenness.