Application of Principal Component Analysis and DoE-Driven Green Analytical Chemistry Concept to Liquid Chromatographic Method for Estimation of Co-formulated Anti-Hypertensive Drugs.

Background: The fixed-dose combination (FDC) of metoprolol succinate (MTS), cilnidipine (CDN), and telmisartan (TST) is used for the management of hypertension. Numerous reversed phase (RP)-HPLC methods have been reported in the literature for chromatographic analysis of MTS, CDN, and TST. According to the concept of green analytical chemistry (GAC), toxic organic solvents should be avoided or minimized during chromatographic method development for the safety of analysts and the protection of the environment. The reported RP-HPLC methods have been developed using acetonitrile (ACN) or methanol as an organic component of the mobile phase and diluent for sample preparation. These organic solvents are considered toxic solvents as per the International Council for Harmonization (ICH) Q3C (R6) guideline and Pfizer medicinal chemistry solvent selection (PMCSS) guide.

Objective: We aimed to develop an environment-friendly and economical RP-HPLC-photo-diode array (PDA) method for the analysis of MTS, CDN, and TST using less toxic organic solvents to support the concept of GAC.

Methods: The method development was carried out by the implementation of chemometrics and design of experiments (DoE) to avoid wastage of organic solvent. Principal component analysis (PCA) was applied as a chemometric tool for the identification of critical method risk variables (MRVs) and method performance attributes (MPAs). The identified critical MRVs and MPAs were further studied by DoE-based response surface modelling for optimization of the method.

Results: The chromatographic analysis of MTS, CDN, and TST was carried out using a Shim-pack ODS column as a stationary phase and ethanol as an organic modifier in the mobile phase. The developed method was applied to the assay of FDCs and results were found to be in compliance with the label claim. The greenness profiles of reported and present RP-HPLC methods were evaluated by national environmental method index (NEMI) and analytical greenness (AGREE) methods.

Conclusion: The developed method was found to be green, robust, and economical as compared to published methods for the analysis.

Highlights: Development and validation of an RP-HPLC method for simultaneous estimation of MTS, CDN, and TST using safe organic solvents. Implementation of a analytical quality by design (AQbD) approach in method development using PCA and DoE. Application of the method for assay of FDCs of MTS, CDN, and TST.