Molecularly Imprinted Electrochemical Sensor-Based Fe2O3@MWCNTs for Ivabradine Drug Determination in Pharmaceutical Formulation, Serum, and Urine Samples.

Fatehy M Abdel-Haleem,Ahmed Barhoum,Mahmoud S Rizk,Eman Gamal,Rasha M El Nashar,Hussam M Elnabawy,Ahmed S G Khalil,Badawi Anis,Adel Madbouly

doi:10.3389/fbioe.2021.648704

Abstract

Ivabradine hydrochloride (IVR) is a medically important drug because of its ability to lower the heart rate. Techniques reported for IVR determination were expensive, laborious, besides being of poor selectivity. In this study, iron oxide @ carbon nanotube (Fe2O3@MWCNTs) nanocomposite and molecularly imprinted polymer (MIP) were synthesized and used in the fabrication of carbon paste electrodes (CPEs) for the potentiometric detection of IVR in biological and pharmaceutical samples. CPEs of the best sensor were formulated from graphite (41 wt%) as a carbon source, MIP (3 wt.%) as an ionophore, Fe2O3@MWCNTs (5 wt%) as a modifier, and nitrophenyl octyl ether (NPOE, 51 wt.%) as a conductive oil so-called plasticizer. The best sensor exhibits a Nernstian slope (response) of 56 mV decade–1 within the IVR concentration range from 1.0 × 10–3 M to 9.8 × 10–8 M with high selectivity against interfering species (ascorbic, maltose, glucose, lactose, dopamine, glycine) over those reported earlier. The use of Fe2O3@MWCNTs together with MIP in the electrode formulation was found to improve the limit of detection (LOD) from 630 to 98 nM along with high reversibility, a short response time of 30 s, and a good lifetime of more than 2 weeks. The sandwich membrane (SMM) method was used to quantify the H-bonding complexing strength of the MIP binding sites for IVR with Log βILn = 11.33. The constructed sensors were successfully applied for the IVR determination in blood serum, urine, and commercial formulations (Savapran®) with high sensitivity.

Highlights

Electrochemical sensors are typically used to estimate the concentrations of many analytes in different samples
The HRTEM images (Figure 2c) show that the MWCNTs have about 20 wellgraphitized walls and are decorated with ∼10 nm Fe2O3 NPs. The fact that these NPs consist of Fe2O3, purified MWCNTs, and Fe2O3@MWCNTs nanocomposite was further examined by XRF, SEM-with elemental mapping, and XRD
A higher binding capacity observed for molecularly imprinted polymers (MIP) compared to non-imprinted polymer (NIP) indicates that the specific binding sites that are available on the as-prepared MIP particles will lead to higher binding efficiency, lower the detection limit, and improve the selectivity toward different molecules or ions that can be present in the tested matrix

Summary

Introduction

Electrochemical sensors are typically used to estimate the concentrations of many analytes (ions, neutral species, and biological molecules) in different samples. A higher binding capacity observed for MIP compared to NIP indicates that the specific binding sites that are available on the as-prepared MIP particles will lead to higher binding efficiency, lower the detection limit, and improve the selectivity toward different molecules or ions that can be present in the tested matrix.

Results

Conclusion