A Molecularly Imprinted Polymeric Sensor Based on Poly(methyldopa) for Electrochemical Quantification of Formoterol in Raw Material and Pharmaceutical Dosage Form

Abstract

<title>Abstract</title> Catechol amine-derived polymers, which include dopamine and its natural analogues, reveal desirable adhesion characteristics, great biocompatibility, and an achievable antifouling surface, by manipulating electro-polymerization procedures. Methyldopa, a synthesised substitute for dopamine which featuring several phenolic, amine, and carboxylic functional groups, a highly specific and selective molecular imprinted polymer (MIP) was utilized. The significant advancements in polymers with molecular imprints, have stimulated the addition of novel molecules as functional monomers to achieve extra precise and more selective electrochemical determination and quantification for the template analyte formoterol fumarate dihydrate (FFD), which utilized as long-acting beta2-agonist in the controlling of asthma and chronic obstructive pulmonary disease (COPD). A polymethyldopa polymer (PMD), was electro-grafted onto pencil graphite electrode (PGE) in the existence of FFD as a template, by UV spectroscopy, the interaction between poly methyldopa (PMD) and template (FFD) has been evaluated. Cyclic voltammetry was applied for electropolymerization of the MIP by scanning potential window over the range of -0.1 to 0.8 voltage versus the reference electrode Ag/AgCl in phosphate buffer at pH equal to 6.5. Indirect method was employed to measure formoterol, where a redox probe (ferrocyanide/ferricyanide) was utilized to detect the binding of FFD to the 3D binding cavities in MIP, by applying the differential pulse voltammetry. The sensor's voltammetric response was steady over a linearity range of 2×10 ^-10 M – 1 ×10 ^-9 M of FFD with a detection limit of 1.7×10 ^-11 M. The International Council for Harmonization’s (ICH) requirements were followed in the validation of the created method, The sensor’s powerful analyte selectivity and sensitivity make it suitable for quantitative evaluation of FFD in the pharmaceutical dosage formulas.